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Protective Device Coordination Protective Device Coordination Document Transcript

  • PROTECTIVE DEVICE COORDINATION Héctor Rivera
  • POYTECHNIC UNIVERSITY OF PUERTO RICO ELECTRICAL ENGINEERING DEPARTMENT HATO REY, PUERTO RICO PROTECTIVE DEVICE COORDINATION GROUP 28 Rivera, Héctor J. Page 2 of 263
  • Table of Contents Table of Pictures ............................................................................................................................. 5 Chapter 1: General Information ...................................................................................................... 8 1.1 Abstracto ..................................................................................................................... 10 1.2 Abstract ....................................................................................................................... 11 1.3 Introduction ................................................................................................................. 12 1.4 Objectives ................................................................................................................... 14 1.5 Constraints .................................................................................................................. 15 Chapter 2: ETAP User Guide ....................................................................................................... 16 2.1 Basic ETAP User Guide ............................................................................................. 18 2.1.1 Creating a new ETAP Project. ............................................................................. 22 2.1.2 Opening an ETAP existing Project. ..................................................................... 23 2.1.3 Building New one-line Diagrams. ....................................................................... 25 2.1.4 Connecting Elements. .......................................................................................... 28 2.1.5 Adding a Protective Device to your One-Line. ................................................... 28 2.1.6 Verify if the element is connected. ...................................................................... 29 2.2 Advance ETAP User Guide ........................................................................................ 30 2.2.1 How to configure the elements in the one-line diagram. ..................................... 34 A) Utility ................................................................................................................. 34 B) High Voltage Circuit Breakers ........................................................................ 36 C) Low Voltage Circuits Breakers ....................................................................... 39 D) Protective Relay ................................................................................................ 44 E) Fuses Ratings .................................................................................................... 49 F) Transformer Properties: .................................................................................. 54 G) Load Properties: ............................................................................................... 57 H) Bus ...................................................................................................................... 58 2.2.2 Perform a Fault Analysis; .................................................................................... 59 Chapter 3: Transformer Case Study.............................................................................................. 61 3.1 Diagrams ..................................................................................................................... 64 3.2 Equipment Data .......................................................................................................... 66 3.3 Calculations ................................................................................................................ 68 3.4 Coordination Using ETAP Program ........................................................................... 73 3.5 Fault Simulation .......................................................................................................... 77 Page 3 of 263
  • 3.6 Settings and Results .................................................................................................... 81 Chapter 4: Bayamón WWTP Coordination Study........................................................................ 84 4.1 Scope ........................................................................................................................... 88 4.2 Electrical System Oneline Diagram ............................................................................ 90 4.3 Imput Data Report ...................................................................................................... 94 4.4 Calculations ................................................................................................................ 97 4.5 Short Circuit Study ................................................................................................... 138 4.6 Power Fuses Selection for Power Transformers T1, T2, T3, T4, T5, T6 and T7 ..... 160 4.7 Protection Relay Settings for ................................................................................. 173 Distribution Feeders ..................................................................................................... 173 4.8 Relay Settings ........................................................................................................... 178 4.9 Results ....................................................................................................................... 181 Chapter 5: Protective Device Coordination Project Results ....................................................... 186 5.1 Alternatives Considered ............................................................................................ 188 5.2 System Specifications ............................................................................................... 191 Operation .................................................................................................................... 193 Protective relay ........................................................................................................... 193 Distance relay ............................................................................................................ 195 Magazine Article............................................................................................................. 197 5.4 Budget ....................................................................................................................... 198 5.5 Bibliography ............................................................................................................. 199 5.6 Conclusion ................................................................................................................ 201 Chapter 6: Administrative Section .............................................................................................. 202 6.1 Protective Device Coordination Project Proposal..................................................... 205 Work Schedule ............................................................................................................ 217 Progress Report ............................................................................................................... 222 Work Schedule ................................................................................................................ 241 Appendix ..................................................................................................................................... 246 Tables and Curves ........................................................................................................... 247 Protection Relay Settings for Generators ........................................................................ 252 A.3 General Information ................................................................................................. 255 Page 4 of 263
  • Table of Pictures Fig. 2.1: Create New Project Panel.................................................................................................... 22 Fig. 2.2: User Information Panel ....................................................................................................... 22 Fig. 2.3: Starting up window ............................................................................................................. 23 Fig. 2.4: Open Panel .......................................................................................................................... 24 Fig. 2.5: Selecting Project.................................................................................................................. 24 Fig. 2.6: Mode Toolbar ...................................................................................................................... 25 Fig.2.7: ETAP Elements .................................................................................................................... 27 Fig. 2.8: Connecting Elements .......................................................................................................... 28 Fig. 2.9: Open Panel .......................................................................................................................... 28 Fig. 2.10: Elements not connected..................................................................................................... 29 Fig. 2.11: Power Grid Editor Window .............................................................................................. 34 Fig. 2.12: High Voltage Circuit Breaker Editor Window .................................................................. 36 Fig. 2.13: Circuit Breaker Library ..................................................................................................... 37 Fig. 2.14: Low Voltage Circuit Breaker Window ............................................................................. 39 Fig. 2.15: Low Voltage Circuit Breaker library ................................................................................ 41 Fig. 2.16: Overcurent Relay Editor Window ..................................................................................... 44 Fig. 2.17: Overcurrent Settings Panel ................................................................................................ 45 Fig. 2.18: Instantaneus Settings Panel ............................................................................................... 46 Fig. 2.19: Fuse Editor Window ......................................................................................................... 49 Fig. 2.20: Fuse Library Window ....................................................................................................... 51 Fig. 2.21: Winding Transformer Editor Window .............................................................................. 54 Fig. 2.22: Transformer Rating Editor Window ................................................................................. 55 Fig. 2.23: Transformer Tap Editor Window ...................................................................................... 56 Fig. 2.24: Lumped Load Editor Window........................................................................................... 57 Fig. 2.25: Bus Editor Window ........................................................................................................... 58 Fig. 2.26: Fault Simulation ................................................................................................................ 59 Fig. 2.27: Select Sequence Viewer to find fault analysis results ....................................................... 60 Fig. 2.28: Results Window ................................................................................................................ 60 Fig. 3.1: Transformer Protection Diagram……………………………………………………....... 65 Fig. 3.2: Selected Fuse…………………………………………………………………………….. 67 Fig. 3.3: Selected Relay…………………………………………………………………………… 67 Fig. 3.4: Table of Current Transformer Specifications…………………………………………… 67 Fig. 3.5: Table of Power Fuse Rating……………………………………………………………... 71 Fig. 3.6: Overcurrent Relay Settings at Transformer……………………………………………... 74 Fig. 3.7: Overcurrent Relay Settings at Load 1,2…………………………………………………. 75 Fig. 3.8: Fuse Settings…………………………………………………………………………….. 76 Fig. 3.9: ETAP Simulation of Fault at Bus 1……………………………………………………… 78 Fig. 3.10: Sequence of Operation Events at Bus 1………………………………………………... 78 Fig. 3.11: ETAP Fault Simulation at Bus 2……………………………………………………….. 79 Fig. 3.12: Sequence of Operation Events at Bus 2………………………………………………... 79 Fig. 3.13: ETAP Fault Simulation at Load 1……………………………………………………… 80 Fig. 3.14: Sequence of Operation Events at Load 1………………………………………………. 80 Fig. 3.15: Relay and Fuse Settings………………………………………………………………... 83 Fig. 3.16: Results of Short Circuit Analysis………………………………………………………. 83 Fig. 4.1: Power Transformer Characteristics Table……………………………………………….. 89 Fig. 4.2: Generator Characteristics Table…………………………………………………………. 89 Fig. 4.3: Original Oneline Diagram of Bayamón WWTP………………………………………… 92 Fig. 4.4: Suggested Oneline Diagram of Bayamón WWTP………………………………………. 93 Fig. 4.5: Lines Cables……………………………………………………………………………... 95 Page 5 of 263
  • Fig. 4.6: Existing Transformer Line Cable. …………………………………………………….... 95 Fig. 4.7: Generator Cables………………………………………………………………………… 95 Fig. 4.8: Positive Sequence impedance Diagram at Bus 1……………………………………....... 99 Fig. 4.9: Three Phase Fault at Bus 1…………………………………………………………… 102 Fig. 4.10: Positive Sequence Impedance Diagram at Bus 2…………………………………… 103 Fig. 4.11: Three Phase Fault at Bus 2 …………………………………………………………… 104 Fig. 4.12: Positive Sequence Impedance Diagram at Load 1……………………………………. 105 Fig. 4.13: Three Phase Fault at Load 1…………………………………………………………... 106 Fig. 4.14: Positive Impedance Diagram at Load 5………………………………………………. 107 Fig. 4.15: Three Phase Fault at Load 6…………………………………………………………... 108 Fig. 4.16: Positive Sequence Impedance Diagram at Bus 1 for a Line to Ground Fault………... 109 Fig. 4.17: Cero Sequence Impedance Diagram at Bus 1……………………………………........ 109 Fig. 4.18: Line to Ground Fault at Bus 1………………………………………………………… 110 Fig. 4.19: Positive Sequence Impedance Diagram at Bus 2 for a Line to Ground Fault………... 111 Fig. 4.20: Cero Sequence Impedance Diagram at Bus 2………………………………………… 111 Fig. 4.21: Line to Ground Fault at Bus 2………………………………………………………… 112 Fig. 4.22: Positive Sequence Impedance Diagram at Load 1 for a Line to Ground Fault………. 113 Fig. 4.23: Cero Sequence Impedance Diagram at Load 1……………………………………….. 113 Fig. 4.24: Line to Ground Fault at Load 1……………………………………………………….. 114 Fig. 4.25: Positive Sequence Impedance Diagram at Load 5 for a Line to Ground Fault………. 115 Fig. 4.26: Cero Sequence Impedance Diagram at Load 5……………………………………….. 115 Fig. 4.27: Line to Ground Fault. At Load 5……………………………………………………... 116 Fig. 4.28: Positive Sequence Impedance Diagram at Generator Bus……………………………. 117 Fig. 4.29: Positive Sequence Impedance Diagram at Bus 2 using Generators………………….. 118 Fig. 4.30: Positive Sequence Impedance Diagram at Load 1 using Generators………………… 119 Fig. 4.31: Positive Sequence Impedance Diagram at Load 5 using Generators………………… 120 Fig. 4.32: Positive Sequence Impedance Diagram at Generators Bus for a Line to Ground Fault. 121 Fig. 4.33: Cero Sequence Impedance Diagram at Generators Bus………………………………. 121 Fig. 4.34: Positive Sequence Impedance Diagram at Bus 2 Using Generators for a Line to Ground Fault……………………………………………………………………………………………… 122 Fig. 4.35: Cero Sequence Impedance Diagram at Bus 2 Using Generators……………………... 123 Fig. 4.36: Positive Sequence Impedance Diagram at Load 1 Using Generators for a Line to Ground Fault……………………………………………………………………………………………… 124 Fig. 4.37: Cero Sequence Impedance Diagram at Load 1 Using Generators……………………. 124 Fig. 4.38: Positive Sequence Impedance Diagram at Load 5 Using Generators for a Line to Ground Fault……………………………………………………………………………………………… 125 Fig. 4.39: Cero Sequence Impedance Diagram at Load 5 Using Generators……………………. 125 Fig. 4.40: Fault Simulation at Primary Side of 38KV/4.16KV Utility Transformer of BWWTP. 140 Fig. 4.41: Sequence of Operations Events at Primary Side of T1……………………………….. 141 Fig. 4.42: Fault Simulation at Bus 1 of BWWTP………………………………………………... 144 Fig. 4.43: Sequence of Operation Events at Bus 1………………………………………………. 145 Fig. 4.44: Fault Simulation at Bus 2 of BWWTP………………………………………………... 148 Fig. 4.45: Sequence of Operation Events at Bus 2………………………………………………. 149 Fig. 4.46: Fault Simulation at Load 1 of BWWTP……………………………………………… 152 Fig. 4.47: Sequence of Operations Events at Load 1……………………………………………. 153 Fig. 4.48: Fault Simulation at Load 6 of BWWTP……………………………………………… 156 Fig. 4.49: Sequence of Operation Events at Load 6……………………………………………... 157 Fig. 4.50: Recommendations to Fuse Protection………………………………………………… 161 Fig. 4.51: Time Fuse 1 and 5 Coordination……………………………………………………… 162 Fig. 4.52: Characteristics Curves for Fuse 1 and 5……………………………………………… 163 Fig. 4.53: Fuse 1 and 5 recommended…………………………………………………………… 164 Page 6 of 263
  • Fig. 4.54: Time Fuse 2 and 6 Coordination……………………………………………………… 165 Fig. 4.55: Characteristics Curves for fuse 2 and 6………………………………………………. 166 Fig. 4.56: Fuse 2 and 6 Recommended………………………………………………………….. 166 Fig. 4.57: Time Fuse 3, 4, 7 and 8 Coordination………………………………………………… 167 Fig. 4.58: Characteristics Curves for fuses 3, 4, 7 and 8………………………………………… 168 Fig. 4.59: Fuse 3, 4, 7 and 8 Recommended……………………………………………….......... 169 Fig. 4.60: Time Fuse 9 Coordination……………………………………………………………. 170 Fig. 4.61: Characteristics Curves for fuse 9……………………………………………………... 171 Fig. 4.62: Fuse 9 Recommended………………………………………………………………… 172 Fig. 4.63: Relay 351A Settings…………………………………………………………………... 179 Fig. 4.64: Overcurent Relay Settings for Generator……………………………………………... 180 Fig. 4.65: Undervoltage, Overvoltage, Frequency of Power Relay for Generator………………. 180 Fig. 4.66: Three Phase Fault Results…………………………………………………………….. 183 Fig. 4.67: Line to Ground Fault Results…………………………………………………………. 184 Fig. 4.68: Three Phase Fault Results Using Generators…………………………………………. 185 Fig. 4.69: Line to Ground Fault Results Using Generators…………………………………........ 185 Fig. 6.1: Protective Devices……………………………………………………………... 213 Fig. 6.2: Budget to Complete Design……………………………………………………. 218 Fig. 6.3: Salary Cap……………………………………………………………………… 218 Page 7 of 263
  • Chapter 1: General Information Page 8 of 263
  • Contents 1.1 Abstracto……………………………………………………………………………... 10 1.2 Abstract………………………………………………………………………………. 11 1.3 Introduction…………………………………………………………………………... 12 1.4 Objectives…………………………………………………………………………….. 14 1.5 Constraints…………………………………………………………………………..... 15 Page 9 of 263
  • 1.1 Abstracto La protección de los sistemas de potencia es uno de los campos más importantes dentro del área de potencia en la ingeniería eléctrica. A través del tiempo se han creado muchísimos programas de computadora con el fin de analizar diseños eléctricos. Nuestro proyecto consiste en preparar una guía de usuario fácil de entender acerca de un programa existente, llamado ETAP, diseñado para realizar análisis de protección de sistemas de potencia. Esta guía de usuario debe incluir como crear un diagrama monolineal, como configurar los equipos de protección, y también la forma correcta de hacer un análisis de fallas y de corto circuito. Finalmente, nosotros preparamos una guía de usuario avanzada con explicaciones detalladas sobre aplicaciones especiales y conceptos técnicos manejados en el programa ETAP. También, como requisito de nuestro proyecto se analiza un caso estudio de un sistema de potencia y se realiza la coordinación de protección del mismo. Page 10 of 263
  • 1.2 Abstract Power Protection is one of the most important fields in Power Electrical Engineering. Through time many software’s has been created to analyze electrical designs. Our project consist of prepare a user guide easy to understand of how to use an existing power protection analysis program calling ETAP. This user guide must include how to create a one-line diagram, how to configure power system devises, and an explanation of the right way to perform a short and fault analysis. Finally, we prepare an advance user guide with detailed explanations of special features and technical concept of ETAP program. Also, as a requirement of our project, we analyzed a case study of power system and perform the protective device coordination of it. Page 11 of 263
  • 1.3 Introduction Electricity has been a subject of scientific interest since at least the early 17th century. Probably the first electrical engineer was William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity. However it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise on Electricity and Magnetism. They are the fathers of electrical engineering and the electric systems. Today, power system protection is that part of electrical power engineering that deals with protecting the electrical power system from faults by isolating the faulted part from the rest of the network. Any electric power system involves a large amount of auxiliary equipment for the protection of generators, transformers, and the transmission lines. Circuit breakers are employed to protect all elements of a power system from short circuits and overloads, and for normal switching operations. The principle of a protection scheme is to keep the power system stable by isolating only the components that are under fault, even as leaving as much of the network as possible still in operation. Thus, protection schemes must apply a very pragmatic and pessimistic approach to clearing system faults. For this reason, the technology and philosophies utilized in protection schemes are often old and well-established because they must be very reliable. In much the same way as the early computers of the 1950s and 1960s were a precursor to the computational capabilities of today’s computers. Specialized hardwire systems were developed for locally monitoring the operation of power plants and for remotely monitoring and controlling switches in transmission substation. The Remote Terminal Units of these early monitoring systems were implemented with relay logic, while Page 12 of 263
  • the master station consisted primarily of large banks of annunciator panels with red and green light indication the state of the points being monitored with flashing light indication a change in state or an alarm condition. The impact of computers has nowhere been more revolutionary than in electrical engineering. The design, analysis and operation of electrical and electronic systems has become completely dominated by computers, a transformation that has been motivated by the natural ease of interface between computers and electrical systems, and the promise of spectacular improvements in speed and efficiency. Our project consists of develop a protective device coordination using a graphical software program to add features and flexibility in the area of electrical system protection. Also, this graphical software program it’s going to be using for all kind of element that used these. We will select the software program, analyze all types of element protection that are utilizing in electrical systems, and simulate the program using various management studies. Page 13 of 263
  • 1.4 Objectives • To make a research about technical references of fuses, relays and breakers. • Understand technical data format of protection devices. • To learn how to use the protective device coordination program. • Create a user guide easy to understand about how to use software program. • Build an advance use guide to explain additional features of software program. • Perform a case study with the software program. • Establish the system coordination of a case study with the program. Page 14 of 263
  • 1.5 Constraints • How to install ETAP program. • Ways to use library of ETAP program. Start by understanding. • Interpret results in the program. • Establish coordination of a protection system. • Run the program with all kind of requisites. • Find right protective devices for design coordination. • Understand how to program protective devices settings of equipments to use. Page 15 of 263
  • Chapter 2: ETAP User Guide Page 16 of 263
  • Contents Basic ETAP User Guide………………………………………………………………………... 18 Creating a new ETAP Project………………………………………………………………….. 22 Opening an ETAP existing Project..……… ………………………………………… 23 Building New one-line Diagram. ……………………………………………………... 25 Connecting Elements……………………………………………………………… 28 Adding Protective Device to your One-Line………………………………………. 28 Verify if the element is connected………………………………………………… 29 Advance ETAP User Guide…..…………………………………………………………... 30 How to configure the elements in the one-line diagram…………………………… 34 Utility……………………………………………………………………… 34 High Voltage Circuit Breakers……………………………………………... 36 Low Voltage Circuit Breaker………………………………………………. 39 Protective Relay……………………………………………………………. 44 Fuses Ratings………………………………………………………………. 49 Transformer Properties………………………………………………..……. 54 Load Properties…………………………………………………………….. 57 Bus…………………………………………………………………………. 58 Perform a Fault Analysis…………………………………………………………... 59 Page 17 of 263
  • 2.1 Basic ETAP User Guide Page 18 of 263
  • Page 19 of 263
  • Contents Creating a new ETAP Project. ...................................................................................................... 22 Opening an ETAP existing Project. .............................................................................................. 23 Building New one-line Diagrams. ................................................................................................ 25 Connecting Elements. ................................................................................................................... 28 Adding a Protective Device to your One-Line. ............................................................................ 28 Verify if the element is connected. ............................................................................................... 29 Page 20 of 263
  • Table of Figure Fig. 2.1: Create New Project Panel .................................................................................................... 22 Fig. 2.2: User Information Panel ....................................................................................................... 22 Fig. 2.3: Starting up window ............................................................................................................. 23 Fig. 2.4: Open Panel .......................................................................................................................... 24 Fig. 2.5: Selecting Project.................................................................................................................. 24 Fig. 2.6: Mode Toolbar ...................................................................................................................... 25 Fig.2.7: ETAP Elements .................................................................................................................... 27 Fig. 2.8: Connecting Elements .......................................................................................................... 28 Fig. 2.9: Open Panel .......................................................................................................................... 28 Fig. 2.10: Elements not connected..................................................................................................... 29 Page 21 of 263
  • 2.1.1 Creating a new ETAP Project. Open the program and select new project. Write the name of the new project and select ok. Fig. 2.1: Create New Project Panel Write the name of the project user and select the access level permissions. Fig. 2.2: User Information Panel Page 22 of 263
  • 2.1.2 Opening an ETAP existing Project. Select open on the ETAP screen. Fig. 2.3: Starting up window To open an existing project must be selected the icon showed. Click the icon and select the project that you want to run in program. Page 23 of 263
  • For example, select document named Protection System Devices and wait until in the next page appears (Fig. 2.5) Fig. 2.4: Open Panel Select icon that has the ETAP symbols. Then click open to see the project at ETAP main window. Fig. 2.5: Selecting Project Page 24 of 263
  • 2.1.3 Building New one-line Diagrams. To build or edit a one-line diagram in ETAP, you must be in Edit Mode. Click the Edit button on the Mode toolbar. Fig. 2.6: Mode Toolbar AC Elements: = Pointer = Bus = 2 winding transformers = 3 winding transformers = cable = Transmission Line = Reactors, Current-Limiting = Impedance = Power grid = Generator = Wind turbine Generator = Induction Machine = Synchronous Motor = Lumped Load = MOV = Static Load = Capacitor = Harmonic Filter = Remote Connector = Static Var Compensator = HV DC Transmission Link = AC Composite Motor = Composite Network = Fuse = Contactor = High Voltage Circuit Breaker = Low Voltage circuit Breaker = Single Throw Switch = Double Throw Switch = Instrumentation = Ground Grid = Display options Page 25 of 263
  • = Schedule Report Manager = Current Transformer (CT) = Potential Transformer (PT) = Voltmeter = Ammeter = Multi-meter = Voltage Relay = Reverse Power Relay = Frequency Relay = MV solid State Trip Relay = Motor Relay = Overcurrent Relay = Overload Heater = Multi-Function Relay = Tag Link DC Elements: = Pointer = Bus = DC Cable = DC Impedance = DC-DC Converter = Battery = DC Motor = DC static Load = DC Lumped Load = Composite CSD = DC Composite Motor = Composite Network = DC Circuit Breaker = DC Fuse = DC Single Throw Switch = DC Double Throw Switch = Un-Interrupted Power System = Variable Frequency Drive = Charger = Inverter Page 26 of 263
  • You can select the element that your project requires for run the short circuit analysis. In the columns you can see all the elements that ETAP program has. Select the elements and drop to the board to complete your diagram. Fig.2.7: ETAP Elements Page 27 of 263
  • 2.1.4 Connecting Elements. To connect the elements in the one-line. Use the mouse pointer over the connection pin of an element, and it will turn red. Then click and drag to the connection pin of another element. Follow this procedure to connect all the elements on the one-line. In the case of buses, the entire element graphic functions as a connection point. Fig. 2.8: Connecting Elements 2.1.5 Adding a Protective Device to your One-Line. To connect the element between two elements does not require delete the line connecting the elements. The element will automatically connect to the line. As shown in the diagram. Fig. 2.9: Open Panel Page 28 of 263
  • 2.1.6 Verify if the element is connected. To check if an element is energized click on the continuity icon ( ) located in the project toolbar. All elements that are not energized will be grayed out. For example, with the continuity check on, open CB4. As shown in the figure to the right, CB4 and elements downstream are grayed out. Fig. 2.10: Elements not connected Page 29 of 263
  • 2.2 Advance ETAP User Guide Page 30 of 263
  • Page 31 of 263
  • Contents How to configure the elements in the one-line diagram. .............................................................. 34 A) Utility ............................................................................................................................. 34 B) High Voltage Circuit Breakers ....................................................................................... 36 C) Low Voltage Circuits Breakers ...................................................................................... 39 D) Protective Relay ............................................................................................................... 44 E) Fuses Ratings .................................................................................................................... 49 F) Transformer Properties: ................................................................................................. 54 G) Load Properties: .............................................................................................................. 57 H) Bus ..................................................................................................................................... 58 Perform a Fault Analysis; ............................................................................................................. 59 Page 32 of 263
  • Table of Figures Fig. 2.11: Power Grid Editor Window .............................................................................................. 34 Fig. 2.12: High Voltage Circuit Breaker Editor Window .................................................................. 36 Fig. 2.13: Circuit Breaker Library ..................................................................................................... 37 Fig. 2.14: Low Voltage Circuit Breaker Window ............................................................................. 39 Fig. 2.15: Low Voltage Circuit Breaker library ................................................................................ 41 Fig. 2.16: Overcurent Relay Editor Window ..................................................................................... 44 Fig. 2.17: Overcurrent Settings Panel ................................................................................................ 45 Fig. 2.18: Instantaneus Settings Panel ............................................................................................... 46 Fig. 2.19: Fuse Editor Window ......................................................................................................... 49 Fig. 2.20: Fuse Library Window ....................................................................................................... 51 Fig. 2.21: Winding Transformer Editor Window .............................................................................. 54 Fig. 2.22: Transformer Rating Editor Window ................................................................................. 55 Fig. 2.23: Transformer Tap Editor Window ...................................................................................... 56 Fig. 2.24: Lumped Load Editor Window........................................................................................... 57 Fig. 2.25: Bus Editor Window ........................................................................................................... 58 Fig. 2.26: Fault Simulation ................................................................................................................ 59 Fig. 2.27: Select Sequence Viewer to find fault analysis results ....................................................... 60 Fig. 2.28: Results Window ................................................................................................................ 60 Page 33 of 263
  • 2.2.1 How to configure the elements in the one-line diagram. A) Utility Rated kV Enter the rated voltage of the power grid in kilovolts (kV). Fig. 2.11: Power Grid Editor Window Generation Categories This group is used to assign the different power settings to each of the ten generation categories for this power grid. Each grid can be set to have a different operating power level for each generation category. Depending on the operation mode, some of the values become editable as follows: • Swing Mode: %V and angle • Voltage Control Mode: %V and MW • Mvar Control: MW and Mvar • Power Factor Control: MW and PF Page 34 of 263
  • SC Rating MVAsc Specify the short-circuit MVA for three-phase and single-phase (line-to-ground) faults. As you enter or modify MVAsc or X/R, ETAP recalculates the corresponding short-circuit impedance values. Page 35 of 263
  • B) High Voltage Circuit Breakers How to change the Rating • Click on either the ANSI or IEC option button to select that standard. Fig. 2.12: High Voltage Circuit Breaker Editor Window Page 36 of 263
  • Library Info To access ANSI standard library data, click on the ANSI selection and then click on the Library button. Use the same procedure for accessing IEC standard library data. As you change the standard from ANSI to IEC, the data fields change accordingly. Rating, ANSI Standard Click on ANSI to enter high voltage circuit breaker ratings according to the ANSI standards. Select the manufacturer and breaker model. Fig. 2.13: Circuit Breaker Library Max kV Select the rated maximum kV of the high voltage circuit breaker in rms kV or select the rating from the list box. Continuous Amp Select the continuous current rating of the high voltage circuit breaker in amperes or select the rating from the list box. Standard Select the high voltage circuit breaker type as Symmetrical or Total rated from the list box. Page 37 of 263
  • Cycle Select the rated interrupting time for AC high voltage circuit breakers in cycles from the list box. CB Cycle Description 2 2-cycle ac high voltage circuit breakers with 1.5-cycle Minimum Contact Parting Time 3 3-cycle ac high voltage circuit breakers with 2-cycle Minimum Contact Parting Time 5 5-cycle ac high voltage circuit breakers with 3-cycle Minimum Contact Parting Time 8 8-cycle ac high voltage circuit breakers with 4-cycle Minimum Contact Parting Time Rated Interrupting Enter the rated short-circuit current (rated interrupting capability) at the rated maximum kV in rms kA or select the rating from the list box. Maximum Interrupting Enter the maximum symmetrical interrupting capability in rms kA or select the rating from the list box. C & L RMS Enter the closing and latching capability of the high voltage circuit breaker in asymmetrical rms kA. This value is equal to 1.6 times the maximum interrupting capability. C & L Crest Enter the closing and latching capability of the high voltage circuit breaker in crest kA. This value is equal to 2.7 times the maximum interrupting capability. Page 38 of 263
  • C) Low Voltage Circuits Breakers Standard Click on either the ANSI or IEC option button to select that standard. Note: once the breaker is selected from the breaker Library Quick Pick the standard is set based on the library entry and is display only. Type Select a type from the drop-down list and display the type of breaker. Low voltage circuit breakers include Molded Case, Power, and Insulated Case breakers. Once the breaker is selected from the breaker Library Quick Pick, the LVCB type is set based on the library entry and is display only. Fig. 2.14: Low Voltage Circuit Breaker Window Page 39 of 263
  • CB and Trip Device library The low voltage circuit breaker data for a selected standard and type can be selected by clicking on the Library button. Standard Click on either the ANSI or IEC option to select that standard. Note that the Standard selection in the breaker library Quick Pick (and hence the breaker models displayed) will be defaulted to the selection. AC/DC Displays that the LV breaker is AC. This option is grayed out and is not available for editing. Type Select from the drop down list and display the breaker type. The LV breaker types include Molded Case, Power and Insulated Case breakers. Note that the Type selection in the breaker library Quick Pick (and hence the breaker models displayed) will be defaulted to the selection made for the breaker type on the Rating page. The breaker type selection can be changed on the Quick Pick if desired. Page 40 of 263
  • Manufacturer Name This displays a list of all AC LV breaker manufacturers included in the library for the selected breaker standard and type. To choose one, just select the manufacturer name. Fig. 2.15: Low Voltage Circuit Breaker library Reference This displays the Manufacturer reference, if available. For example, Westinghouse is the reference for Cutler Hammer. Page 41 of 263
  • Model Name The Model section displays list of all models for the selected standard, breaker type and breaker manufacturer. The models are displayed in the form of Model – Max kV – Pole, which forms a unique record name in the breaker library. Select the Model – Max kV – Pole by highlighting it. ANSI Short-Circuit data When ANSI standard is selected, the short-circuit data shows the applied voltage in kV, short-circuit interrupting current for the applied voltage in kA, and test power factor in %, for all breaker types. The short-circuit parameters are explained in more detail in the Ratings section. Select a desired applied voltage and short-circuit data by highlighting it. Size This displays a list of all sizes available for the selected Model, Max. kV, and Pole record for the breaker. To select a size from the Library Quick Pick, highlight the size. Ratings, ANSI Standard Click on ANSI standard button and choose the breaker type to enter the ratings for LV circuit breaker in accordance with the ANSI/IEEE standards. When a breaker is selected from Library Quick Pick, all parameters shown below will be set to their corresponding values chosen from the Quick Pick. With the exception of Size, changing the values after selecting a breaker from Library Quick Pick will turn the header blue to indicate that the substituted library data has been modified. Size Select an item from the drop-down list to display the size in amperes for the selected breaker. Page 42 of 263
  • Continuous Amp Select an item from the drop-down list or enter the continuous current rating for the low voltage circuit breaker in amperes. The Continuous Amp value will be set equal to the breaker size when a breaker is selected from the breaker Library Quick Pick. Rated kV Select an item from the drop-down list or enter the rated kV rating for the low voltage circuit breaker in kV. When a breaker is selected, the rated kV value will be set equal to the applied kV selected from Library. Test PF This is the power factor of test equipment on which the rating of the circuit breaker has been established. When a breaker is selected, the Test PF is set to the Test PF value selected from Library. Fused For all breaker types, select fused or unfused by clicking on the provided selection box. Note that when a breaker is selected from library, the Fused checkbox is set to the status as selected from the Quick Pick. The value of Test PF will change appropriately for fused or unfused type, in case of Power breakers. Interrupting kA Select from drop down list or enter the Interrupting kA rating for the low voltage circuit breaker in kA. Note that when a breaker is selected, the interrupting kA value will be set equal to the kA value for selected applied kV from library Quick Pick. Page 43 of 263
  • D) Protective Relay Fig. 2.16: Overcurent Relay Editor Window Library To access the Overcurrent relay library data, click on the Library button. Clicking the Library button displays the relay library Quick Pick. From the Library, select the relay by highlighting the Manufacturer name and Model name. Then click on the OK button to retrieve the selected data from the library and transfer it to the editor. OC level Overcurrent relays can have multiple Time overcurrent (TOC) and/or Instantaneous overcurrent (IOC) elements that can simultaneously and independently set in the relay library. The OC level displays a drop down list of the maximum number of overcurrent levels that are available for the selected relay. Page 44 of 263
  • Overcurrent (51) Settings The Time overcurrent settings available for Phase, Neutral, Ground, Sensitive Ground and Negative Sequence are described below. Fig. 2.17: Overcurrent Settings Panel Pickup Range Select from drop down list and display the Time overcurrent Pickup range for the selected curve. The pickup range can be specified in amperes of the secondary or primary current rating. It can also be in multiples/percent of the CT secondary. Pickup Setting For the selected pickup range, select or enter the Time overcurrent pickup setting. The pickup setting can be discrete values or continuously adjustable. Relay Amps This field displays the relay secondary current in amperes, for the selected pickup setting. Prim. Amps This field displays the relay primary current in amperes, for the selected pickup setting. Page 45 of 263
  • Time Dial Select and display the Time Dial for the selected curve type. The time dial can be discrete values or continuously adjustable. Instantaneous (50) Settings The Instantaneous settings available for Phase, Neutral, Ground, Sensitive Ground and Negative Sequence are described below. Fig. 2.18: Instantaneus Settings Panel Page 46 of 263
  • Curve Type This field with a drop down list of curves is available only if the selected relay has Short time feature and if the Short time is selected. Select from the drop down list and display the Short time curve type for the selected model. Pickup Range Select from the drop down list and display the Instantaneous Pickup range (for the selected curve in case of Short time). The pickup range can be specified in amperes of the secondary or primary current rating. It can also be in multiples/percent of the CT secondary or 51 pickup. Pickup Setting For the selected pickup range, select or enter the Instantaneous pickup setting. The pickup setting can be discrete values or continuously adjustable. Relay Amps This field displays the relay secondary current in amperes, for the selected pickup setting. Prim. Amps This field displays the relay primary current in amperes, for the selected pickup setting. Delay Range This field is available only if the relay has Instantaneous function. Select from the drop down list and display the Instantaneous Delay range. The delay range could either be in seconds or cycles. Delay Select or enter the intentional delay for the instantaneous. The Delay can be in seconds or cycles, depending on the selection of relay. The delay can be in the form of discrete values or continuously adjustable. Page 47 of 263
  • Time Dial This field is available only if the selected relay has Short time feature and if the Short time is selected. Select or enter the Time Dial for the selected curve type. The time dial can be discrete values or continuously adjustable. Page 48 of 263
  • E) Fuses Ratings Standard Click either the ANSI or IEC button option to select that standard. Once the fuse is selected from the Library Quick Pick - Fuse, the standard is set based on the library entry and is display only. Rating, ANSI Standard Click on ANSI standard to enter the ratings for Fuse in accordance with the ANSI/IEEE standards. When a Fuse is selected from library Quick Pick, all parameters shown below will be set to their corresponding values chosen from the Quick Pick. With the exception of Size, changing the value(s) after selecting a fuse from library Quick Pick will turn the header to blue color indicating that the substituted library data has been modified. Fig. 2.19: Fuse Editor Window Page 49 of 263
  • kV Select from drop down list or enter the rated kV rating for the Fuse in kV. When a Fuse is selected, the Rated kV value will be set equal to the Max. kV selected from library Quick Pick. Size Select from the drop-down list and display the size in amperes for the selected fuse. Note: the Size field will be empty when no fuse is chosen from Library Quick Pick. Continuous Amp Select from drop down list or enter the continuous current rating for the Fuse in amperes. The Continuous Amp value will be set equal to the fuse size when a fuse is selected from library Quick Pick. Interrupting Select from the drop-down list or enter the Interrupting kA rating for the Fuse in kA. Note: when a Fuse is selected, the interrupting kA value will be set equal to the kA value for selected fuse size from Library Quick Pick. Test PF Enter the power factor of test equipment on which the rating of the fuse has been established. When a fuse is selected, the Test PF is set to the Test PF value selected from library Quick Pick. Page 50 of 263
  • Library (Quick Pick) To select a fuse from the library, click the Library button and the Library Quick Pick – Fuse dialog box will appear. From the dialog box, select a fuse by selecting the Manufacturer name and the desired fuse Model, Max kV, and Speed. This represents a unique record. Select the desired size and short circuit interrupting kA. Then click the OK button to retrieve the selected data from the library and transfer it to the editor. Fig. 2.20: Fuse Library Window Standard Click on either the ANSI or IEC option to select that standard. Note that the Standard selection in the Fuse library Quick Pick (and hence the fuse models displayed) will be defaulted to the selection made for the standard on the Rating page. The standard selection can be changed on the Quick Pick if desired. Page 51 of 263
  • Manufacturer Manufacturer Name Displays a list of all AC Fuse manufacturers included in the library for the selected standard. Select the manufacturer by highlighting the manufacturer name. Reference Displays a manufacturer reference, if available, for selected manufacturer. For example, Siemens is the reference manufacturer for ITE. Model Name The Model section displays list of all fuse models for the selected standard and fuse manufacturer. The models are displayed in the form of Model – Max kV – Speed, which forms a unique record name in the fuse library. Select the Model – Max kV – Speed by highlighting it. Cont. Amp This displays the ampere value corresponding to each size for the selected fuse model. Int. kA (ANSI Standard) This displays the short-circuit interrupting rating in kA corresponding to each size for the selected ANSI fuse model. Model Info Class This displays the class (E-rated, for example) for the selected fuse model. Page 52 of 263
  • Type This displays the type (Power Fuse, for example) for the selected fuse model. Brand Name It shows the brand name, if available, for the selected fuse model. Reference It demonstrates the reference, if available, for selected fuse model. Application Present the application for the selected fuse model. Page 53 of 263
  • F) Transformer Properties: You can open the editor for T2 and go to the Rating page. On the rating page you can enter the value of the primary kV, secondary kV, primary winding rating in kVA or MVA, and the maximum transformer rating. Additionally, you can enter the impedance or substitute typical values for the transformer. Fig. 2.21: Winding Transformer Editor Window Page 54 of 263
  • Transformer Ratings Fig. 2.22: Transformer Rating Editor Window Rating of Transformer: Enter the rating of KV primary and secondary. Enter the rating of MVA. Enter the Typical X/R. Enter the Z variation and Z Tolerance. You may select the typical rating. Page 55 of 263
  • Transformer Tap The Transformer Tap Optimization calculation optimizes a unit transformer tap, or equivalently, its turn ratio, to ensure that the generator unit voltage remains within its upper and lower variation range (typically 95% to 105%), while producing its full MW and Mvar capability under the system voltage variation. Fig. 2.23: Transformer Tap Editor Window Page 56 of 263
  • G) Load Properties: In this part you can go to the Nameplate page. The available fields in the rating section depend on the Model Type selected. In the Ratings section enter the lumped load rating in MVA or MW. Furthermore, the % loading for various loading categories can be specified here. Fig. 2.24: Lumped Load Editor Window Page 57 of 263
  • H) Bus Nominal kV Enter the nominal voltage of the bus in kilovolts (kV). In/Out of Service The operating condition of a bus can be selected by choosing either the In Service or Out of Service option. Fig. 2.25: Bus Editor Window Page 58 of 263
  • 2.2.2 Perform a Fault Analysis; Star View: Click Star Protective Device Coordination. Fig. 2.26: Fault Simulation Page 59 of 263
  • Select Sequence Viewer to find the result of the Protective Device Cordination. Fig. 2.27: Select Sequence Viewer to find fault analysis results It will show the results to be show in the report. The sequence of operation is on order to the parameters of the system. Fig. 2.28: Results Window Page 60 of 263
  • Chapter 3: Transformer Case Study Page 61 of 263
  • Contents Diagrams………………………………………………………………………………… ..64 Equipment Data……………………………………………………………………………66 Calculations………………………………………………………………………………..68 Coordination Using ETAP Program……………………………………………………….73 Fault Simulation……………………………………………………………………………77 Results………………...……………………………………………………………………81 Page 62 of 263
  • Table of Figures Fig. 3.1: Transformer Protection Diagram……………………………………………………....... 65 Fig. 3.2: Selected Fuse…………………………………………………………………………….. 67 Fig. 3.3: Selected Relay…………………………………………………………………………… 67 Fig. 3.4: Table of Current Transformer Specifications…………………………………………… 67 Fig. 3.5: Table of Power Fuse Rating……………………………………………………………... 71 Fig. 3.6: Overcurrent Relay Settings at Transformer……………………………………………... 74 Fig. 3.7: Overcurrent Relay Settings at Load 1,2…………………………………………………. 75 Fig. 3.8: Fuse Settings…………………………………………………………………………….. 76 Fig. 3.9: ETAP Simulation of Fault at Bus 1……………………………………………………… 78 Fig. 3.10: Sequence of Operation Events at Bus 1………………………………………………... 78 Fig. 3.11: ETAP Fault Simulation at Bus 2……………………………………………………….. 79 Fig. 3.12: Sequence of Operation Events at Bus 2………………………………………………... 79 Fig. 3.13: ETAP Fault Simulation at Load 1……………………………………………………… 80 Fig. 3.14: Sequence of Operation Events at Load 1………………………………………………. 80 Fig. 3.15: Relay and Fuse Settings………………………………………………………………... 83 Fig. 3.16: Results of Short Circuit Analysis………………………………………………………. 83 Page 63 of 263
  • 3.1 Diagrams Page 64 of 263
  • 3.1.1 Transformer Case Study Diagram: Fig. 3.1: Transformer Protection Diagram Our Transformer Case Study has the following components: a) One transformer 38/4.16 KV of 7.5/11.3 MVA. b) Two feeders. Protection has to be able to extinguish faults that affect the system. It scheme consist of protective relaying and fuses. Coordination criteria have 22 cycles between protection levels. We considered selectivity, reliability and simplicity to accomplish with a scheme protection safety. Page 65 of 263
  • 3.2 Equipment Data Page 66 of 263
  • Equipment Data: Specification of electric fuse Fuse Continuous Maximum Fuse Name Size Type Amperes KV Cutler Hammer Standard 150E 150 17 BA-200 Speed Fig. 3.2: Selected Fuse Relay settings Relay TOU IOU Location Relay Name 51 & Curve 50 & 50N 51N ABB 51D 0.5-80; 0.5-80; Extremely Feeder with 50 0.1 steps 0.1 steps Inverse (60Hz) ABB 51D Main 0.5-80; 0.5-80; Very with 50 Breaker 0.1 steps 0.1 steps Inverse (60Hz) Fig. 3.3: Selected Relay Selected current transformer Current Transformer Location CTR Type Main 2,500/5 MR C400 Breaker Load 800/5 MR C400 Fig. 3.4: Table of Current Transformer Specifications Page 67 of 263
  • 3.3 Calculations Page 68 of 263
  • Power System Coordination calculation: 1) Calculating the short circuit current: 375MVA ISC = = = 5, 697.53 A 3(38 KV ) 7.5MVA IBASE = = 113.95 A 3(38 KV ) 5, 697.53 I pu = = 50.0 pu 113.95 1 Z pu = = 0.02 pu 50.0 1∠00 ISC = = 11.11 p 0.02 + 0.07  38  IBASE = (113.95)   = 11,564.3 A  4.16  Page 69 of 263
  • 2) Calculating the multiples of the relay in the load, to verify the necessary time dial in the curves: 11, 565.3 M= = 13.6 850 3) Obtaining the pick-up current for the relay in the transformer: Pickup = (1568.28)(1.2) = 1881.93A 4) The multiples of the current transformer (CTM) in the transformer: 11,565.3 M= = 6.14 1,881.93 5) The calculation for choose the CTR: CTR = 2000/5 11.3MVA IFL = = 1, 568.28 A ISC = 11,565.04 3(4.16 KV ) a) CTR > 1,568.28(1.2) = 1,881.93A b) ISC/CTR < 100 A 11,565.04/400 < 100 Page 70 of 263
  • 6) Calculation for choosing fusible: Using the standard Speed curve Step 1: Full load Current 11.3MVA 7.5MVA IFL = = 171.68 A INM = = 113.95 A 3(38 KV ) 3(38 KV ) Data: 46 Kv Power Fuses (Show & Standard Speed) Rating Continuous Current Operating Time 100E 165 See curves… 125E 181 See curves… Fig. 3.5: Table of Power Fuse Rating F1 ≥ 125E Step 2: Inrush Current IINRUSH = 113.95(12) = 1,367.48 A @ 6 cycles F1 ≥ 100E Step 3: Short circuit current 11,564.3 ISC = = 1, 266.1A @ 43.2 cycles F1 ≥ 175E  38     4.16  Step 4: Turning Ratio  I NOMINAL  FR =   > 1.5 < 3  I NOMINAL TRANS.   213  =  = 1.86 1.5 < 1.86 < 3  113.95  The fuse chosen is 175E because it complied with the parameters of the design. Fuse will be 175E and can handle 213 Amps. Page 71 of 263
  • Using the Slow Speed curve: Step 1: Full load Current 11.3MVA IFL = = 171.68 A 3(38 KV ) Data: 46 Kv Power Fuses (Slow & Standard Speed) Rating Continuous Current Operating Time 100E 165 See curves… 125E 181 See curves… Fig. 3.5: Table of Power Fuse Rating F1 ≥ 125E Step 2: Inrush Current IINRUSH = 113.95(12) = 1,367.48 @ 6 ciclos F1 ≥ 80E Step 3: Short circuit current 11,564.3 ISC = = 1, 266.1A @ 43.2 ciclos F1 ≥ 125E  38     4.16  Step 4: Turning Ratio  I NOMINAL  FR =   > 1.5 < 3  I NOMINAL TRANS.   181  =  = 1.58 1.5 < 1.58 < 3  113.95  The fuse chosen is 125E because it complied with the parameters of the design. Page 72 of 263
  • 3.4 Coordination Using ETAP Program Page 73 of 263
  • Overcurrent: To protect our transformer power system we choose a relay distributed by ABB with overcurrent and instantaneous settings. This setting for overcurrent was given using a Definite Time Curve. The pick range is specified by 5 amperes of the secondary or primary rating. Using this setting the relay will operate when primary current exceed 2,500A. Time dial of overcurrent relay is given by curve type and changing it by time required. In the other side, to operate instantaneous relay is necessary select a pick up according to short circuit current. These input settings are introduced at ETAP window showing below. Overcurrent Relay settings in the transformer: Fig. 3.6: Overcurrent Relay Settings at Transformer. In this case the curve selected was Definite Time. Page 74 of 263
  • Another section of our power system that required protection are load 1 and 2 feeders. To protect these feeders we select an ABB instantaneous and overcurrent relay. The overcurrent settings were chosen by a Definite Time Curve. The pick range is specified by 5 amperes of the secondary side of relay. Using this setting the overcurrent will operate when line current exceed 850A. Time dial is given by relay curve according to time required for current magnitude. In the other side, to operate instantaneous relay is necessary select a pick up according to short circuit current. When current reach 11,568; instantaneous protection must operate. These input settings are introduced at ETAP window showing below. Overcurrent relay setting at load 1,2: Fig. 3.7: Overcurrent Relay Settings at Load 1,2 Page 75 of 263
  • Fuse Setting: In order to perform good protective device coordination is necessary implement use of almost one fuse. The fuse selected by us is S&C, SMU-20. It is modeling by an standard speed curve with short circuit current of 10KA. Also it has a maximum rated voltage of 38KV. Finally, the size of fuse is 200E with a 200 continuous amperes. Fig. 3.8: Fuse Settings Page 76 of 263
  • 3.5 Fault Simulation Page 77 of 263
  • Short circuit results: Fig. 3.10: Sequence of Operation Events at Bus 1 Fig. 3.9: ETAP Simulation of Fault at Bus 1 Protection in the system can not protect for a fault at bus 1. It should be protected by other protective device out of our system. Page 78 of 263
  • Figures below show short circuit results at bus 2 when operate the instantaneous relay 2. The instantaneous relay work to open the circuit and if it does not operate fuse 1 operate to disconnect system. Relay 2 operates at 2.75 cycles after a fault occurs. If relay 1 does not work, fuse 1 is going to operate at 52.56 cycles. Fig. 3.12: Sequence of Operation Events at Fig. 3.11: ETAP Fault Simulation at Bus 2 Bus 2 Page 79 of 263
  • In figures below you can see short circuit results at load 1. Instantaneous relay 3 will open first. If it does not operate, time overcurrent relay 2. But, if it also does not work, fuse 1 must open with a time delay. Fig. 3.14: Sequence of Operation Events at Load 1 Fig. 3.13: ETAP Fault Simulation at Load 1 ETAP program gives results of short circuit. Short circuit current is 21,570 at load 1. With this current we choose settings for relay 3. Short circuit at load 1 is the same results at load 2. Sequence operation work with a sequence coordination of 22 cycles approximated. Relay 3 operates at 7.74 cycles covered by relay 2 witch operates at 28.86 cycles like primary protection. Page 80 of 263
  • 3.6 Settings and Results Page 81 of 263
  • Settings and Results We perform protective device coordination for a transformer and two loads. In order to express our results and recommendations clearly, we organized all data in tables. These tables include devices and fuse settings. In the figure 3.15 you can find curves type, pick-up and time dial to obtain better results with the protective device coordination. In the other side, three phase fault table contents short circuits results in different section of system. The figure 3.16 shows short circuit current magnitude in different parts of system. First, the table presents a three phase fault at feeder #1. Short circuit current at this point is 11,564A. With this fault feeder relay will operates at 2.76 cycles like primary protection. If the feeder relay does not operate, main breaker feeder will operate at 25.86 cycles. When system has a fault at primary side of transformer #1, the fuse will operate at 52.56 cycles. Relays in our system use definite time curve. It is use to chose time dial of relay operation. In the other way, fuse 1 is modeling with a standard speed curve. Using these settings the protection is complete according with coordination criteria. Page 82 of 263
  • Equipment Settings Equipment Settings Time Equipment Curve Pick-up Dial Feeder Definite 2,500 1.895 Relay Time Main Definite Breaker 850 1.895 Time Relay Standard Fuse X X Speed Fig. 3.15: Relay and Fuse Settings Fault Results Three Phase Fault Short Operation Protection Devices Localization Circuit Feeder Main Fault Current Relay Breaker Fuse (51) Relay (51) Feeder #1 or 11,564 2.76 25.86 52.56 #2 A 11,566 Bus #2 X 2.76 52.56 A 10,500 T1 Primary X X 52.56 A T1 Secondary 9,950 A X X X Fig. 3.16: Results of Short Circuit Analysis Page 83 of 263
  • Chapter 4: Bayamón WWTP Coordination Study Page 84 of 263
  • Contents Scope……………………………………………………………………………………….. 88 Electrical System Oneline Diagram……………………………………………………….... 90 Imput Data Report………………………………………………………………………… 94 Calculations………………………………………………………………………………... 97 Short Circuit Study………………………………………………………………………. 138 Power Fuse Selection for Power Transformer T1, T2, T3, T4, T5, T6 and T7………….. 160 Protection Relay Settings for Distrbution Feeders………………………………………. 173 Relay Settings……………………………………………………………………………. 178 Results……………………………………………………………………………………. 181 Page 85 of 263
  • Table of Figure Fig. 4.1: Power Transformer Characteristics Table………………………………………………... 89 Fig. 4.2: Generator Characteristics Table…………………………………………………………. 89 Fig. 4.3: Original Oneline Diagram of Bayamón WWTP………………………………………… 92 Fig. 4.4: Suggested Oneline Diagram of Bayamón WWTP………………………………………. 93 Fig. 4.5: Lines Cables……………………………………………………………………………... 95 Fig. 4.6: Existing Transformer Line Cable. ……………………………………………………… 95 Fig. 4.7: Generator Cables………………………………………………………………………… 95 Fig. 4.8: Positive Sequence impedance Diagram at Bus 1………………………………………... 99 Fig. 4.9: Three Phase Fault at Bus 1……………………………………………………………... 102 Fig. 4.10: Positive Sequence Impedance Diagram at Bus 2……………………………………... 103 Fig. 4.11: Three Phase Fault at Bus 2 …………………………………………………………… 104 Fig. 4.12: Positive Sequence Impedance Diagram at Load 1……………………………………. 105 Fig. 4.13: Three Phase Fault at Load 1…………………………………………………………... 106 Fig. 4.14: Positive Impedance Diagram at Load 5………………………………………………. 107 Fig. 4.15: Three Phase Fault at Load 6…………………………………………………………... 108 Fig. 4.16: Positive Sequence Impedance Diagram at Bus 1 for a Line to Ground Fault………... 109 Fig. 4.17: Zero Sequence Impedance Diagram at Bus 1……………………………………........ 109 Fig. 4.18: Line to Ground Fault at Bus 1………………………………………………………… 110 Fig. 4.19: Positive Sequence Impedance Diagram at Bus 2 for a Line to Ground Fault………... 111 Fig. 4.20: Zero Sequence Impedance Diagram at Bus 2………………………………………… 111 Fig. 4.21: Line to Ground Fault at Bus 2………………………………………………………… 112 Fig. 4.22: Positive Sequence Impedance Diagram at Load 1 for a Line to Ground Fault………. 113 Fig. 4.23: Zero Sequence Impedance Diagram at Load 1……………………………………….. 113 Fig. 4.24: Line to Ground Fault at Load 1……………………………………………………….. 114 Fig. 4.25: Positive Sequence Impedance Diagram at Load 5 for a Line to Ground Fault………. 115 Fig. 4.26: Zero Sequence Impedance Diagram at Load 5……………………………………….. 115 Fig. 4.27: Line to Ground Fault. At Load 5……………………………………………………... 116 Fig. 4.28: Positive Sequence Impedance Diagram at Generator Bus……………………………. 117 Fig. 4.29: Positive Sequence Impedance Diagram at Bus 2 using Generators………………….. 118 Fig. 4.30: Positive Sequence Impedance Diagram at Load 1 using Generators………………… 119 Fig. 4.31: Positive Sequence Impedance Diagram at Load 5 using Generators………………… 120 Fig. 4.32: Positive Sequence Impedance Diagram at Generators Bus for a Line to Ground Fault 121 Fig. 4.33: Zero Sequence Impedance Diagram at Generators Bus……………………………… 121 Fig. 4.34: Positive Sequence Impedance Diagram at Bus 2 Using Generators for a Line to Ground Fault……………………………………………………………………………………………… 122 Fig. 4.35: Zero Sequence Impedance Diagram at Bus 2 Using Generators……………………... 123 Fig. 4.36: Positive Sequence Impedance Diagram at Load 1 Using Generators for a Line to Ground Fault……………………………………………………………………………………………… 124 Fig. 4.37: Zero Sequence Impedance Diagram at Load 1 Using Generators……………………. 124 Fig. 4.38: Positive Sequence Impedance Diagram at Load 5 Using Generators for a Line to Ground Fault……………………………………………………………………………………………… 125 Fig. 4.39: Zero Sequence Impedance Diagram at Load 5 Using Generators……………………. 125 Fig. 4.40: Fault Simulation at Primary Side of 38KV/4.16KV Utility Transformer of BWWTP. 140 Fig. 4.41: Sequence of Operations Events at Primary Side of T1……………………………….. 141 Fig. 4.42: Fault Simulation at Bus 1 of BWWTP………………………………………………... 144 Fig. 4.43: Sequence of Operation Events at Bus 1………………………………………………. 145 Fig. 4.44: Fault Simulation at Bus 2 of BWWTP……………………………………………….. 148 Fig. 4.45: Sequence of Operation Events at Bus 2………………………………………………. 149 Fig. 4.46: Fault Simulation at Load 1 of BWWTP……………………………………………… 152 Page 86 of 263
  • Fig. 4.47: Sequence of Operations Events at Load 1……………………………………………. 153 Fig. 4.48: Fault Simulation at Load 6 of BWWTP……………………………………………… 156 Fig. 4.49: Sequence of Operation Events at Load 6……………………………………………... 157 Fig. 4.50: Recommendations to Fuse Protection………………………………………………… 161 Fig. 4.51: Time Fuse 1 and 5 Coordination……………………………………………………… 162 Fig. 4.52: Characteristics Curves for Fuse 1 and 5……………………………………………… 163 Fig. 4.53: Fuse 1 and 5 recommended…………………………………………………………… 164 Fig. 4.54: Time Fuse 2 and 6 Coordination……………………………………………………… 165 Fig. 4.55: Characteristics Curves for fuse 2 and 6………………………………………………. 166 Fig. 4.56: Fuse 2 and 6 Recommended………………………………………………………….. 166 Fig. 4.57: Time Fuse 3, 4, 7 and 8 Coordination………………………………………………… 167 Fig. 4.58: Characteristics Curves for fuses 3, 4, 7 and 8………………………………………… 168 Fig. 4.59: Fuse 3, 4, 7 and 8 Recommended……………………………………………….......... 169 Fig. 4.60: Time Fuse 9 Coordination……………………………………………………………. 170 Fig. 4.61: Characteristics Curves for fuse 9……………………………………………………... 171 Fig. 4.62: Fuse 9 Recommended………………………………………………………………… 172 Fig. 4.63: Relay 351A Settings………………………………………………………………….. 179 Fig. 4.64: Overcurent Relay Settings for Generator……………………………………………... 180 Fig. 4.65: Undervoltage, Overvoltage, Frequency of Power Relay for Generator………………. 180 Fig. 4.66: Three Phase Fault Results…………………………………………………………….. 183 Fig. 4.67: Line to Ground Fault Results…………………………………………………………. 184 Fig. 4.68: Three Phase Fault Results Using Generators…………………………………………. 185 Fig. 4.69: Line to Ground Fault Results Using Generators…………………………………........ 185 Page 87 of 263
  • 4.1 Scope Page 88 of 263
  • Scope Develop a short circuit study for Power Transformers and relay settings for a waste water treatment plant and the protective devices associated. The Bayamón Waste Water Treatment Plant has seven large power transformers with their respective protective devices (power fuses or protective relaying) in service. The intention of this short circuit study is to verify the appropriated protective device coordination and recommended the appropriated changes if any. For this plant we will cover the relay coordination and settings for the protective device associated. The short circuit current available at Bayamón Waste Water Treatment Plant, with 38 kV connection tap, is submitted by Puerto Rico Electric Authority (PREPA). Three phase short circuit current is 20,000 A and 11,547 A for phase to ground. The ETAP Power Simulation computer program, version 5.5 from Operation Technology, Inc was used for all the short circuit studies and simulations. The following tables detail information available for the electrical Fig. 4.1: Power equipment from the electrical drawings for Bayamón Waste Water Transformer Treatment Plant. This information will be the data base for the short circuit Characteristics Table study. Power Transformer # T1 T2 T3 T4 T5 T6 T7 Characteristics 1 Voltage in kV 38/4.16 4.16/0.48 4.16/0.48 38/4.16 4.16/0.48 4.16/0.48 4.16/0.48 2 Capacity in MVA 5 1.5 1.5 5 1.5 1.5 0.15 3 Impedance in % 6.21 3 3 6.21 3 3 2.5 4 Connection D-Y D-Y D-Y D-Y D-Y D-Y D-Y # Generator (1 to 2) Value Units SEL 300G Characteristics 1 Terminal Voltage 4.16 kV 2 Capacity 2500 KW 3 Power Factor 0.8 Fig. 4.2: Generator Characteristics 4 Full Load 347.37 Amps Table. 5 Synchronous Reactance 2.14 6 Transient Reactance 0.19 7 Substransient Reactance 0.14 8 Negative Sequence Reactance 0.19 9 Zero Sequence Reactance 0.05 Page 89 of 263
  • 4.2 Electrical System Oneline Diagram Page 90 of 263
  • Diagrams We were required to perform an analysis for choose necessary equipment to protect electric power system o Bayamón Waste Water Treatment Plant. After analizing the system, we decided to use following coordination equation; t2 = 1.3t1 +15. Using it, we set next coordination level between 23 to 25 cycles. In order to find the best devices to perform a good protective device coordination, we analized a lot of different devices. The selected devices are commonly used in power systems. It help very much to find devices information. Selected fuses were exclusive to accomplish all requirements. Chosen devices and results are showed through next pages. Page 91 of 263
  • Bayamón WWTP Case Study Fig. 4.3: Original Oneline Diagram of Bayamón WWTP. This is the original oneline diagram given to us with the objective of perform the protective device coordination. It does not include any protective device. Page 92 of 263
  • Bayamón WWTP Sugested Oneline Diagram Fig. 4.4: Suggested Oneline Diagram of Bayamón WWTP. Above diagram shows all suggested protective devices for power system of Bayamón WWTP. Each device was selected to guarantee the best protective device coordination. Shortly we present complete analysis of this coordination. Page 93 of 263
  • 4.3 Input Data Report Page 94 of 263
  • Data: Lines cables 500 MCM TRXLPE Z+ =(32+j36) µΩ/ft Z0 =(104+j18) µΩ/ft Lines Distance R+ X+ R0 X0 L1 120’ 0.00384 0.00432 0.01248 0.00216 L2 120’ 0.00384 0.00432 0.01248 0.00216 L3 1000’ 0.032 0.036 0.104 0.018 L4 15’ 0.032 0.036 0.104 0.018 L5 15’ 0.00048 0.00054 0.00156 0.00027 L6 15’ 0.00048 0.00054 0.00156 0.00027 L7 15’ 0.00048 0.00054 0.00156 0.00027 L8 15’ 0.00048 0.00054 0.00156 0.00027 Fig. 4.5: Lines Cables. This table includes power system feeders’ parameters. Line cable 2/0 AWG Cu TRXLPE Z+ =(103+j44) µΩ/ft Z0 =(400+j25) µΩ/ft Lines Distance R+ X+ R0 X0 L9 100’ 0.0103 0.0044 0.04 0.0025 Fig. 4.6: Existing Transformer Line Cable. The figure presents cable characteristics of an existing transformer. Generators cables 350 MCM TRXLPE + Z =(42+j38) µΩ/ft Z0 =(154+j20) µΩ/ft Lines Distance R+ X+ R0 X0 LG1 75’ 0.00315 0.00285 0.01155 0.0015 LG2 75’ 0.00315 0.00285 0.01155 0.0015 Fig. 4.7: Generator Cables. Table above shows parameters of cables using for generators. Page 95 of 263
  • Project: ETAP Page: 1 5.5.0C Location: Date: 04-16-2007 Contract: SN: BETA-ELECT Engineer: Revision: Base Study Case: SM Filename: JHD-CS Config.: Normal 2-Winding Transformer Input Data Transformer Rating Z Variation % Tap Setting Adjusted Phase Shift ID MVA Prim. kV Sec. kV %Z X/R + 5% - 5% % Tol. Prim. Sec. %Z Type Angle T1 5.000 38.000 4.160 6.21 12.14 0 0 0 0 0 6.2100 Std Pos. Seq. -30.0 T2 1.500 4.160 0.480 3.00 7.10 0 0 0 0 0 3.0000 Std Pos. Seq. -30.0 T3 1.500 4.160 0.480 3.00 7.10 0 0 0 0 0 3.0000 Std Pos. Seq. -30.0 T4 5.000 38.000 4.160 6.21 12.14 0 0 0 0 0 6.2100 Std Pos. Seq. -30.0 T5 1.500 4.160 0.480 3.00 7.10 0 0 0 0 0 3.0000 Std Pos. Seq. -30.0 T6 1.500 4.160 0.480 3.00 7.10 0 0 0 0 0 3.0000 Std Pos. Seq. -30.0 T7 0.150 4.160 0.480 2.50 20.00 0 0 0 0 0 2.5000 Std Pos. Seq. -30.0 2-Winding Transformer Grounding Input Data Grounding Transformer Rating Conn. Primary Secondary ID MVA Prim. kV Sec. kV Type Type kV Amp Ohm Type kV Amp Ohm T1 5.000 38.000 4.160 D/Y Solid T2 1.500 4.160 0.480 D/Y Solid T3 1.500 4.160 0.480 D/Y Solid T4 5.000 38.000 4.160 D/Y Solid T5 1.500 4.160 0.480 D/Y Solid T6 1.500 4.160 0.480 D/Y Solid T7 0.150 4.160 0.480 D/Y Solid Page 96 of 263
  • 4.4 Calculations Page 97 of 263
  • Impedance: Distance at lines. Line1 = Line2 = 120 ' Line3 = Line4 = 1000 ' Line5−8 = 15' Line9 = 100 ' LineG1 = LineG 2 = 75' The cable used is TRXLPE 500 MCM. µΩ Z + LINE1−2 = (32 + j 36) (120 ') ft Z + LINE1− 2 = (0.00384 + j 0.00432)Ω µΩ Z 0 LINE1−2 = (104 + j18) (120 ') ft Z 0 LINE1− 2 = (0.01248 + j 0.00216)Ω  Ω  Z 0 LINE1− 2 =  (1.04 + j 0.18)   1000 '  Z 0 LINE1− 2 = (0.1248 + j 0.0216)Ω  µΩ  Z + LINE 3− 4 =  (32 + j 36)  (1000 ')  ft  Z + LINE 3− 4 = (0.032 + j 0.036)Ω  µΩ  Z 0 LINE 3−4 =  (104 + j18)  (1000 ')  ft  Z 0 LINE 3− 4 = (0.104 + j 0.018)Ω µΩ Z + LINE 5−8 = (32 + j 36) (15') ft Z + LINE 5−8 = (0.00048 + j 0.00054)Ω µΩ Z 0 LINE 5−8 = (104 + j18) (15') ft Z 0 LINE 5−8 = (0.00156 + j 0.00027)Ω µΩ Z + LINE 9 = (103 + j 44) (100 ') ft Z + LINE 9 = (0.0103 + j 0.0044)Ω µΩ Z 0 LINE 9 = (400 + j 25) (100 ') ft Z 0 LINE 9 = (0.04 + j 0.0025)Ω Page 98 of 263
  • Generators and Cable Equipment Electrical Specification: The cable used is TRXLPE 350 MCM. Ω Z + LINE −G1 = Z + LINE −G 2 = (42 + j 38) (75') 1000 ' Z + LINE −G1 = Z + LINE −G 2 = (0.00315 + j 0.00285)Ω Ω Z 0 LINE −G1 = Z 0 LINE −G 2 = (154 + j 20) (75') 1000 ' Z 0 LINE −G1 = Z 0 LINE −G 2 = (0.01155 + j 0.0015)Ω Page 99 of 263
  • Calculating 3φ Short Circuit MVA with the utility: Positive sequence impedance diagram for determine the fault current at the bus 1: Fig. 4.8: Positive Sequence impedance Diagram at Bus 1 The shtort circuit current from utility: ISCH = 20,000 A S SCH = 3(VL − L )( I SCH ) S SCH = 3(38kv)(20, 000 A) = 1316MVA Finding base current: SBASE = 5 MVA VBASE = 38 KV S I BASE = BASE 3VBASE 5MVA I BASE = = 76.05 A 3(38kV ) Converting short circuit current in per unit: I I pu = real I BASE 20, 000 A I pu = = 263 pu 76.05 A Page 100 of 263
  • Calculating the per unit current to per unit impedance. 1∠0 Z pu = = 3.8022*10−3 pu 263 pu Simulating a short circuit at secondary side of transformer: (V ) 2 Z BASE = BASE S BASE (38Kv) 2 Z BASE = = 289Ω 5MVA The base impedance at the other side of the transformer. (289Ω) Z BASE = 2 = 3.46Ω  38kV     4.16kV  Calculating the line one impedance in per unit: Z Z L1 pu = real Z BASE 0.00144Ω Z L1 pu = = 0.416*10−3 pu 3.46Ω Calculating short circuit current at the bus 1: 4.16 I BASE = (76.05 A)( ) = 698.68 A 0.48 1∠0o I SCH pu = ZTH pu 1∠0o I SCH = = 15.07 pu (3.8022*10−3 ) pu + (0.0621) pu + (0.416*10−3 ) pu Changing per unit current to real current: I SCH p = (15.07 pu )(694.68 A) = 10, 468.83 A Page 101 of 263
  • Fig. 4.9: Three Phase Fault at Bus 1 Analysis For the short circuit showed above, the device that operates are the instantaneous (50) and back-up relay (51). If relay does not operate, fuse 1 will operate likes back up. This coordination has approximately a 25 cycles different to the other coordination. Transferring current to the other side of transformer 1: I SCHprimary I SCH sec ondary = a (10, 468.83) I SCH sec ondary = = 1,146.06 A  38     4.16  Page 102 of 263
  • Positive sequence impedance diagram for current fault at the bus 2: Fig. 4.10: Positive Sequence Impedance Diagram at Bus 2 Converting line three impedance to per unit: 0.012Ω Z L 3 pu = = 0.003468 pu 3.46Ω Doing a short circuit at the bus 2: 1∠0o I SCH = = 14.33 pu (3.8022*10−3 ) pu + (0.0621) pu + (0.416*10−3 ) pu + (0.003468) pu Changing the current in amperes: I BASE = 694.68) A I SCH = (14.33 pu )(694.68 A) = 9,954.76 A Page 103 of 263
  • ETAP Short circuit results: Fig. 4.11: Three Phase Fault at Bus 2 Analysis For this short circuit the device that operates as primary protection is fuse 2. If fuse does not operate, relay (51) will operate as back up with approximately 25 cycles of different to the other coordination. Page 104 of 263
  • Doing a short circuit at load 1: Positive sequence impedance diagram for current fault at the load 1: Fig. 4.12: Positive Sequence Impedance Diagram at Load 1 Calculating line five per unit impedance: 0.00027Ω Z L 5 pu = = 0.078*10 −3 pu 3.46Ω Changing transformer impedance: 5MVA Z newT 3 = 0.03 pu ( ) = 0.1 pu 1.5MVA 1∠0o I SCH = = 5.89 pu (3.8022*10 ) pu + (0.416*10 ) pu + (0.0621) pu + (0.003468) pu + (0.078*10−3 ) pu + (0.1) pu −3 −3 Transferring current in secondary side of transformer: 4.16kV I BASE = (694.68 A)( ) = 6014 A 480 I SCH = (6014 A)(5.89 pu ) = 35, 461.1A Page 105 of 263
  • ETAP Short Circuits Results: Fig. 4.13: Three Phase Fault at Load 1 Analysis A fault at transformer 2 or 3 has a protection in secondary side. Fuse 3 will operates like a back up with 25 cycles of different between primary protection. If fuse 3 does not operate, fuse 2 will operate with 25 cycles different between the fuse 3. Page 106 of 263
  • Doing a short circuit at load five: Positive sequence impedance diagram for a short circuit current at the load 5: Fig. 4.14: Positive Impedance Diagram at Load 5 Calculating new impedance of transformer 7: 5MVA Z newT 7 = 0.025 pu ( ) = 0.833 pu 0.15MVA Changing line impedance to per unit impedance: 0.0044Ω Z Line9 = = 0.001272 pu 3.46Ω 1∠0o I SCH = = 1.11 pu (3.8022*10−3 ) pu + (0.416*10−3 ) pu + (0.0621) pu + (0.001272) pu + (0.833) pu The real current in amperes: I SCH = (1.11 pu )(6020.56) = 6, 682.82 A Page 107 of 263
  • ETAP Short circuits results: Fig. 4.15: Three Phase Fault at Load 6 Analysis Transformer 7 has a protection in the secondary side as a protection to faults as showing above. Fuse 9 will operates like a back up with 9 cycles of different between primary protection. Page 108 of 263
  • Calculating line to ground Short Circuit MVA: Positive sequence impedance diagram for determine the short circuit curremt at the bus 1: Fig. 4.16: Positive Sequence Impedance Diagram at Bus 1 for a Line to Ground Fault. ZTH ( + ) = (3.8022*10 −3 + 0.0621 + 0.416 *10−3 ) pu = 0.066318 pu Cero sequence impedance diagram for determine the short circuit curremt at the bus 1: Fig. 4.17: Zero Sequence Impedance Diagram at Bus 1 0.000720 Z L1(0) = = 0.208*10−3 pu 3.36 ZTH (0) = (0.208*10−3 + 0.0621) pu = 0.062308 pu Short circuit at the bus1:  1∠00  I0 =  (+) (−)   ZTH 2 + ZTH   1∠00  I0 =   = 5.12 pu  ((0.066318)2 + 0.0837) pu  I SCH = (5.12 pu )(3) = 15.38 I SCH = (15.38 pu )(694.68 A) = 10, 684.17 A Page 109 of 263
  • ETAP Short circuits Results: Fig. 4.18: Line to Ground Fault at Bus 1 Analysis When a line to ground fault occurs at bus 1 the instantaneous (50N) and back-up relay (51N) must operate. If they do not operate, then fuse 1 will operate likes back up. This coordination has approximately a 25 cycles different to other coordination. Page 110 of 263
  • Short circuit at the bus 2: Positive sequence impedance diagram for determine the short circuit curremt at the bus 2: Fig. 4.19: Positive Sequence Impedance Diagram at Bus 2 for a Line to Ground Fault. Z ( + ) = (3.8022*10−3 + 0.0621 + 0.416*10−3 + 0.003468) pu = 0.06978 pu Cero sequence impedance diagram for determine the short circuit curremt at the bus 2: Fig. 4.20: Zero Sequence Impedance Diagram at Bus 2. 0.006 Z L 3(0) = = 0.001734 pu 3.46 Z (0) = (0.208*10−3 + 0.0621 + 0.001734) pu = 0.06404 pu  1∠00  I0 =   = 4.9 pu  (0.06978)2 + 0.06404) pu  I SCH = (4.9 pu )(3 A) = 14.7 A I SCH = (14.7 pu )(694.68) = 10, 211.79 A Page 111 of 263
  • ETAP Short Circuit Results: Fig. 4.21: Line to Ground Fault at Bus 2. Analysis For this short circuit the device that operates as primary protection is fuse 2. If fuse does not operate, relay (51N) will operate as back up with approximately 25 cycles of diffe different to the other coordination. Page 112 of 263
  • Short circuit at the load 1: Positive sequence impedance for determine the short circuit current at the load 1: Fig. 4.22: Positive Sequence Impedance Diagram at Load 1 for a Line to Ground Fault. Z ( + ) = (3.8022*10−3 + 0.0621 + 0.416*10−3 + 0.003468 + 0.27 *10−3 + 0.1) pu = 0.17005 pu Cero sequence impedance for determine the short circuit current at the load 1: Fig. 4.23: Zero Sequence Impedance Diagram at Load 1. 0.135*10−3 Z L 5(0) = = 0.039*10−3 3.46 Z (0) = 0.1 pu The short circuit current:  1∠00  I0 =   = 2.27 pu  (0.17005)2 + 0.1) pu  I SCH = (2.27 pu )(3) = 6.81 pu I SCH = (6.81 pu )(6020.56 A) = 41, 039 A Page 113 of 263
  • ETAP Short Circuits Results: Fig. 4.24: Line to Ground Fault at Load 1. Analysis Transformer 2 has a protection in secondary side. The fuse 3 will operates like a back up with 25 cycles of different in between primary protection. If fuse 3 does not operate, fuse 2 will operate with 25 cycles different between the fuse 3. Page 114 of 263
  • Short circuit at the load 5: Positive sequence impedance for determine the short circuit current at the load 5: Fig. 4.25: Positive Sequence Impedance Diagram at Load 5 for a Line to Ground Fault. Z ( + ) = (3.8022*10−3 + 0.0621 + 0.416*10−3 + 0.0044 + 0.833) pu = 0.9037 pu Cero sequence impedance for determine the short circuit current at the load 5: 0Z Transformer 7 Fig. 4.26: Zero Sequence Impedance Diagram at Load 5. Z (0) = 0.833 pu The short circuit current:  1∠00  I0 =   = 0.3787 pu  (0.9037)2 + 0.833) pu  I SCH = (0.3787 pu )(3) = 1.13 pu I SCH = (6020.56)(1.13 pu ) = 6,803.23 A Page 115 of 263
  • ETAP Short Circuit Results: Fig. 4.27: Line to Ground Fault. At Load 5 Analysis Transformer 7 has a protection in the secondary side against line to ground faults. If a fault of this type happens, fuse 9 will operates like a back up with 9 cycles of different between primary protection. Page 116 of 263
  • Calculating 3φ Short Circuit with generators: Simulating a short circuit at bus 1: Positive sequence impedance to determine the short circuit current at the generator bus: Fig. 4.28: Positive Sequence Impedance Diagram at Generator Bus. Finding the new impedance of the generators: 2 V  S  Z NEW = Z puold  BASEOLD   BASENEW   VBASENEW   S BASEOLD  2  4.16kV   5MVA  −3 Z NEW = 0.19     = 4.55*10 pu  38kV   2.5MVA  Changing the generators impedance to per unit impedance: 0.00285Ω Z LG1 = Z LG 2 = = 0.824*10−3 pu 3.46Ω The impedance at the bus 1: 2  VBASE   S BASENEW  Z NEW G1 = Z NEW G 2 = Z puold      VBASENEW   S BASEOLD      2  4.16   5MVA  −3 Z NEW G1 = Z NEW G 2 = 0.19    2.5MVA  = 4.55*10 pu  38    Z G1+ LG1 // Z G 2+ LG 2 Z G1+ LG1 // Z G 2 + LG 2 = 2.687 *10−3 pu Calculating the short circuit current: 1∠0 1∠0 I SCH = = ZTH Z G1+ LG1 // Z G 2 + LG 2 1∠0 I SCH = = 372.16 pu 2.687 *10−3 pu Changing the per unit current to real current: I BASE = 694.68 A I SCH = (372.16 pu )(694.68 A) = 258,532.1A Page 117 of 263
  • Positive sequence impedance to determine the short circuit current at the bus 2: Fig. 4.29: Positive Sequence Impedance Diagram at Bus 2 using Generators. Doing a short circuit at the bus 2: 1∠0 1∠0 I SCH = = ZTH Z LG1 // Z LG 2 + Z L 3 1∠0 I SCH = = 162.46 pu (2.687 *10 + 3.468*10−3 ) pu −3 Changing the per unit current to real current: I SCH = (162.46 pu )(694 A) = 112,864.33 A Page 118 of 263
  • Positive sequence impedance to determine a short circuit current at the load 1: Fig. 4.30: Positive Sequence Impedance Diagram at Load 1 using Generators. Doing a short circuit at the load 1: 1∠0 1∠0 I SCH = = ZTH Z G1+ LG1 // Z G 2 + LG 2 + Z L 3 + Z L 5 + ZT 2 1∠0 I SCH = = 9.41 pu (2.687 *10 + 3.468*10−3 + 0.078*10−3 + 0.1) pu −3 Converting the per unit current to real current: I BASE = 6020.56 A I SCH = (9.41 pu )(6020.56 A) = 56, 673.16 A Page 119 of 263
  • Positive sequence impedance to determine a short circuit current at load 5: Fig. 4.31: Positive Sequence Impedance Diagram at Load 5 using Generators. Doing a short circuit at the secondary size of transformer 7: 1∠0 1∠0 I SCH = = ZTH Z G1+ LG1 // Z G 2 + LG 2 + Z L 4 + Z L 9 + ZT 7 1∠0 I SCH = −3 = 1.19 pu (2.687*10 + 0.001272 + 0.833) pu Changing the per unit current to real current: I SCH = (1.19 pu )(6020.56 A) = 7,193.37 A Page 120 of 263
  • Fault line to ground using the generators: Positive sequence impedance to determine a short circuit current at the generator bus: Fig. 4.32: Positive Sequence Impedance Diagram at Generators Bus for a Line to Ground Fault. ZTH + = 2.687 *10 −3 pu Cero sequence impedance to determine a short circuit current at the generator bus: Fig. 4.33: Zero Sequence Impedance Diagram at Generators Bus. Finding the new impedance of the generators: 2  VBASEOLD   S BASENEW      0 Z = Z puold NEW  VBASE   S BASE   NEW   OLD  2  4.16kV   5MVA  Z 0 NEW = 0.05    −3  = 1.198*10 pu  38kV   2.5MVA  Page 121 of 263
  • The impedance at the bus 1: 0.015Ω Z 0 LG1 = = 4.34*10 −3 pu 3.45Ω Z G1+ LG1 = Z 0 G 2+ LG 2 = (1.198*10 −3 + 0.434 *10 −3 ) pu = 1.632*10−3 pu 0 Z 0TH = Z G1+ LG1 // Z G 2+ LG 2 = 0.816 *10−3 pu Calculating the short circuit current: 1∠0 I0 = 2( Z TH ) + ZTH 0 + 1∠0 I0 = = (161.5 pu )3 = 484.65 pu  2(2.687 *10 ) + 0.816 *10 −3  pu  −3  Changing the per unit current to real current: I SCH = (484.65 pu )(694.68 A) = 336, 678.51A Positive sequence impedance to determine a short circuit current at the bus 2: Fig. 4.34: Positive Sequence Impedance Diagram at Bus 2 Using Generators for a Line to Ground Fault. Z +TH = Z G1+ LG1 // Z G 2 + LG 2 + Z L 3 + Z L 5 = (2.687 *10−3 + 3.468*10−3 ) pu = 6.155 pu Page 122 of 263
  • Cero sequence impedance to determine a short circuit current at the bus 2: Fig. 4.35: Zero Sequence Impedance Diagram at Bus 2 Using Generators. Z 0TH = Z G1 // Z G 2 + Z L 3 + Z L 5 = (0.816*10−3 + 1.734 *10 −3 ) pu = 2.55*10 −3 pu Doing a short circuit at the bus 2: 1∠0 I0 = = 67.29 pu [ 2(0.006155) + 0.00255] pu I SCH = (67.29 pu )(3) = 201.88 pu Changing the per unit current to real current: I SCH = (201.88 pu )(694.68 A) = 140, 244.95 A Page 123 of 263
  • Positive sequence impedance to determine a short circuit current at the load 1: Fig. 4.36: Positive Sequence Impedance Diagram at Load 1 Using Generators for a Line to Ground Fault. ZTH + = (6.155*10−3 + 0.078*10−3 + 0.1) pu = 0.1062 pu Cero sequence impedance to determine a short circuit current at the load 1: Fig. 4.37: Zero Sequence Impedance Diagram at Load 1 Using Generators. Doing a short circuit at the load 1: Z 0TH = ZT 2 = 0.1 pu The short circuit current: 1∠0 I0 = = 3.2 pu [ 2(0.1062) + 0.1] pu I SCH = (3.2 pu )(3) = 9.6 pu Converting the per unit current to real current: I SCH = (9.6 pu )(6020.56 A) = 57,815.87 A Page 124 of 263
  • Positive sequence impedance to determine a short circuit current at the load 5: Fig. 4.38: Positive Sequence Impedance Diagram at Load 5 Using Generators for a Line to Ground Fault. Z + TH = Z G1+ LG1 // Z G 2+ LG 2 + Z L 4 + Z L 9 + Z T 7 = (0.816 *10−3 + 1.272 *10−3 + 0.833) pu = 0.835 pu Cero sequence impedance to determine a short circuit current at the load 5: Fig. 4.39: Zero Sequence Impedance Diagram at Load 5 Using Generators. Z 0TH = ZT 7 = 0.833 pu Doing a short circuit at the secondary side of the transformer 7: 1∠0 I0 = = 0.39 pu [ 2(0.835) + 0.833] pu I SCH = (0.39 pu )(3) = 1.19 pu Changing the per unit current to real current: I SCH = (1.19 pu )(6020.56 A) = 7,164.46 A Page 125 of 263
  • Selecting the fuses: Fuse at transformer 3: Using the slow speed curve 1) Step 1: Nominal Current 1.5MVA I No min al = = 208.4 A 3(38kV ) F ≥ 300 E 2) Step2: Inrush current I Inrush = (208.42)(12) = 2,501A @ 6 cycles F ≥ 300 E These fuses hold 9,546 A. 3) Step 3: Short circuit current I SCH = 4, 090 A Looking in the graph total clearing time. The fuse opens at 0.396s or 23.76 cycles. Fuse at the bus 3: Using the Time-delayed fuse 1) Step 1: Nominal current 3MVA I No min al = = 416 A 3(4.16kV ) F ≥ 600 2) Step 2: Inrush current I Inrush = (208)(12) + 208 = 2, 704 A @ 6 cycles F ≥ 600 These fuse hold 7,037 A at 6 cycles. 3) Step 3: Short circuit current I SCH = 9,950 A Using the graph total clearing time the fuse will open at 0.027s or 1.62 cycles. Page 126 of 263
  • The fuses at the transformer number 7. Using the standard speed curve 1) Step 1: Nominal current 0.15MVA I No min al = = 20.8 A 3(4.16kV ) F ≥ 30 E 2) Step 2: Inrush current I Inrush = (20.8)(12) = 250 A @ 6 cycles F ≥ 30 E These fuse hold 1,015 A at 6 cycles. 3) Step 3: Short circuit current I SCH = 772 A Finding the graph total clearing time the fuse will open at 0.133s or 7.98 cycles. Fuse at the Utility: Using the very slow speed curve 1) Step 1: Nominal current 5MVA I No min al = = 75.97 A 3(38kV ) F ≥ 100 2) Step 2: Inrush current I Inrush = (76)(12) = 912 A @ 6 cycles F ≥ 100 These fuse hold 3,754 A at 6 cycles. 3) Step 3: Short circuit current I SCH = 20, 000 A Finding the graph total clearing time the fuse will open at 0.025s or 1.5 cycles. Page 127 of 263
  • Calculating Relays: Selecting the CTR for the transformers: a) The CTR has to comply with all the methods: I N = 695 A  695 A  CTR ≥ 1.2    5  1200  695 A  ≥ 1.2   5  5  240 ≥ 167 The CTR complied with the equation. I SC b) ≤ 100 A CTR 3, 460 ≤ 100 A 240 14.4 ≤ 100A The ratio between the short circuit and the CTR complied with the requirement. CTRvoltage c) Burden( z ) = 20 I N 1200 Burden( z ) = = 0.086Ω 20(695 A) The burden could not exceed 0.086Ω. Page 128 of 263
  • Selecting the CTR for the generators: a) I N = 695 A  695 A  CTR ≥ 1.2    5  7000  695 A  ≥ 1.2   5  5  1400 ≥ 167 The CTR complied with the equation. I SC b) ≤ 100 A CTR 133, 248 A ≤ 100 A 7, 000 5 95 ≤ 100A The ratio between the short circuit and the CTR complied with the requirement. CTRvoltage c) Burden( z ) = 20 I N 7, 000 Burden( z ) = = 0.5Ω 20(695 A) The Burden could not exceed 0.5Ω. Page 129 of 263
  • Equation Curve: Relay 351A: Three phase fault at the bus 1 using utility: Setting Overcurrent Relay: Element 50 I SCH = 10,104 A The multiple to use in the ETAP Program: I M = SCH CTR 10,104 A M= = 42.1 Instantaneous operation time 1, 200 5 Element 51 Pick − up = 1.2 I FL Pick − up = 1.2(695 A) = 834 A Aproximated in ETAP program 816A . I SCH M= Pick − up 9, 950 M= = 12.19 816 Time Operation Equation TPRELAY = 0.344 s  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  0.344 = TD 0.0352 +   12.192 − 1  TD = 4.67 Using the Extremely Inverse Curve Page 130 of 263
  • Line to ground fault at the bus 1 using utility: Setting for Overcurrent Relay. Element 50N I SCH = 10,104 A Multiple used in the ETAP program. I M = SCH CTR 10,104 A M= = 42.1 1, 200 5 Instantaneous operation time Element 51N I SCH = 10, 729 A 834 A Pick − up = 1.2(695 A) = = 278 A 3 The multiple used in the ETAP program. The multiple used in the curves. I I SCH M = SCH M= CTR Pick − up 278 A 10, 729 M= = 1.15 steps = 0.01 M= = 37.25 1200 288 5 Operation Time Equation: TPRELAY = 0.335s  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  0.335 = TD 0.0352 +   37.252 − 1  TD = 8.53 Using the Extremely Inverse Curve Page 131 of 263
  • Generation Operation Overcurrent Relay: Relay 300G: Three phase fault at the bus G using generators: Primary protection 3φ Short circuit at the bus of the each generator: 258,532.1A I SCH = = 129, 266.05 A 2 The multiple to be used the relay curve. 129, 266.05 M= = 310.10 416.84 Element 51 The pick-up current for the relay. I FL = 347.37 A Pick − up = 1.2 I FL Pick − up = 1.2(347.37 A) = 416.84 A Finding the operation time relay.  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  TPR ELAY = 8.48 0.0352 +  = 0.298s  310.10 2 − 1  TPR ELAY = 0.298s Using extremely inverse curve. Page 132 of 263
  • Element 50 Multiple used in ETAP program. 100, 000 M= = 71.42 7, 000 5 Element 51N The pick-up current for the relay. I FL = 347.37 A 1.2 I FL Pick − up = 3 1.2(347.37 A) Pick − up = = 130.95 A 3 Short circuit Line to ground at the bus of the generator: 336, 678.51A I SCH = = 168,339.25 A 2 Finding the multiple to be used in the ETAP program: 168, 339.25 M= = 1, 285.52 130.95 Finding operation time relay. TD = 8.52  5.67  TPR ELAY = 8.52 0.0352 + 2  = 0.299 s  1, 285.52 − 1  TPR ELAY = 0.299 s Using extremely inverse curve Element 50N The multiple used in ETAP program. I SCH = 200, 000 A 200, 000 M= = 142.85 7, 000 5 Page 133 of 263
  • Generator Relay working as backup protection. Doing a 3φ Fault at the bus 2: Element 51 The pick-up current for the relay. Pick − up = 416.84 A The short circuit current of each generator. 112,864.3 I SCH = = 54, 432.15 2 The multiple to be used in the Relay curve. 54, 432.15 M= = 135.38 416.84 Finding the operation time relay.  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  TPR ELAY = 8.48 0.0352 +  = 0.29 s  135.382 − 1  TPR ELAY = 0.29 s Using extremely inverse curve Page 134 of 263
  • Doing a Line to ground fault at the bus 2: Element 51N The pick-up current for the relay. 416.84 A Pick − up = = 138.94 A 3 The schort circuit current . 140, 244.95 A I SCH = = 70,122.47 A 2 The multiple to be used in the Relay curve. 70,122.47 M= = 504.67 138.94 Finding the operation time relay.  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  TPR ELAY = 8.52 0.0352 +  = 0.30 s  504.67 2 − 1  TPR ELAY = 0.30 s Using extremely inverse curve Page 135 of 263
  • Doing a 3φ Fault at the load 1: Element 51 Short circuit current at load 1. I SCH = 56, 673.16 A Transferring short circuit current to generators side. 56, 673.16 A I SCH = = 6,539.21A 4.16 0.48 Current contribution of each generator. 6, 539.21A I SCH = = 3, 296.6 A 2 The pick-up current for the relay. Pick − up = 416.84 A Multiple to be used in Relay curve. 3, 296.6 M= = 7.84 416.84 Finding operation time relay.  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  TPR ELAY = 8.48 0.0352 +  = 1.093s  7.842 − 1  TPR ELAY = 1.093s Using extremely inverse curve Page 136 of 263
  • Doing a Line to ground fault at the load 1: Element 51N The pick-up current for the relay. 416.84 A Pick − up = = 138.94 A 3 The short circuit current . 57,815.87 A I SCH = = 6, 671.06 A 4.16 0.48 The short circuit current of each generator. 6, 671.06 I SCH = = 3,335.53 A 2 The multiple to be used in the Relay curve. 3, 335.53 M= = 24 138.94 Finding the operation time relay.  5.67  TPR ELAY = TD 0.0352 + 2   M −1  5.67  TPR ELAY = 8.52 0.0352 + 2  = 0.38s  24 − 1  TPR ELAY = 0.38s Using extremely inverse curve Page 137 of 263
  • 4.5 Short Circuit Study Page 138 of 263
  • Short Circuit Study A. Single Line Short circuit SM Report - Short Circuit Study for the Power Transformers T1, T2, T3, T4, T5, T6 and T7. The section VI. A. contains the ETAP computer program output single line short circuit cases and SM reports, detailing the short circuit current available in each distribution voltage buses. The following table contains the power transformer characteristics and short circuit summary. # Power Transformers T1 T2 T3 T4 T5 T6 T7 Characteristics 1 Voltage in kV 38/4.16 4.16/0.48 4.16/0.48 38/4.16 4.16/0.48 4.16/0.48 4.16/0.48 2 Capacity in MVA 5 1.5 1.5 5 1.5 1.5 0.15 3 Impedance in % 6.21 3 3 6.21 3 3 2.5 4 Connection D-Y D-Y D-Y D-Y D-Y D-Y D-Y Secondary Winding Short 5 Circuit Three Phase Current 20,000 4,090 4,090 20,000 4,090 4,090 772 (A) at High Side Secondary Winding Short 6 Circuit Three Phase Current 10,520 35,440 35,440 10,520 35,440 35,440 6,690 (A) at Low Side Secondary Winding Short 7 Circuit Line to Ground 0 0 0 0 0 0 0 Current (A) at High Side Secondary Winding Short 8 Circuit Line to Ground 10,730 41,060 41,060 10,730 41,060 41,060 6,850 Current (A) at Low Side Each simulation page includes the incoming short circuit current magnitude from the 38 kV PREPA’S electric power system (20000 amps for three phase and 11547 amps for phase to ground) and the secondary current at distribution voltage busses at Bayamón Waste Water Treatment Plant. Page 139 of 263
  • 4.5.1: Three phase fault at utility Fig. 4.40: Fault Simulation at Primary Side of 38KV/4.16KV Utility Transformer of BWWTP *Note: The presented fault is the same at T4 primary side. Page 140 of 263
  • Fig. 4.41: Sequence of Operations Events at Primary Side of T1. When a three phase fault arise at primary side of 38KV/4.16KV transformer (T1) the fuse 1 will operate at 1.50 cycles (24.9ms) as shown above. Page 141 of 263
  • Project: Protective Device Coordination ETAP Page: 1 5.5.0C Location: WWTP, Bayamon Date: 04-16-2007 Contract: SN: BETA-ELECT Engineer: Hector, Jose, Daniel Revision: Base Study Case: SM Filename: JHD-CS Config.: Normal SHORT- CIRCUIT REPORT Fault at bus: BTP-2 Prefault voltage = 38.000 kV = 100.00 % of nominal bus kV ( 38.000 kV) = 100.00 % of base kV ( 38.000 kV) Positive & Zero Sequence Impedances Contribution 3-Phase Fault Line-To-Ground Fault Looking into "From Bus" From Bus To Bus %V kA % Voltage at From Bus kA Symm. rms % Impedance on 100 MVA base ID ID From Bus Symm. rms Va Vb Vc Ia 3I0 R1 X1 R0 X0 BTP-2 Total 0.00 20.000 0.00 173.21 173.21 0.000 0.000 3.79E-001 7.59E+000 BTS-2 BTP-2 0.00 0.000 100.00 100.00 100.00 0.000 0.000 Utility 1 BTP-2 100.00 20.000 0.00 173.21 173.21 0.000 0.000 3.79E-001 7.59E+000 Bus-1 BTS-2 0.00 0.000 100.00 100.00 100.00 0.000 0.000 Bus-2 Bus-1 0.00 0.000 100.00 100.00 100.00 0.000 0.000 Bus-1 Bus7 0.00 0.000 100.00 100.00 100.00 0.000 0.000 # Indicates fault current contribution is from three-winding transformers * Indicates a zero sequence fault current contribution (3I0) from a grounded Delta-Y transformer Page 142 of 263
  • Analysis When the system has a Three Phase Fault the impedance view is only the utility impedance. The impedance is founded by Puerto Rico Electric Authority (PREPA). We can find the short circuit current in the line asking to PREPA which is the short circuit current at that point of the system. However when the system occur a Line to Ground Fault the transformers configuration is Delta at the primary winding and the circuit impedance is open by the configuration. For these reason the short circuit current is zero amperes. Page 143 of 263
  • 4.5.2: Three phase fault at bus 1 Fig. 4.42: Fault Simulation at Bus 1 of BWWTP *Note: The presented fault is the same at bus 6. Page 144 of 263
  • Fig. 4.43: Sequence of Operation Events at Bus 1 Analysis For the short circuit showed above, the device that operates are the instantaneous (50) and back-up relay (51). If relay does not operate, fuse 1 will operate likes back up. This coordination has approximately a 25 cycles different to the other coordination. Page 145 of 263
  • Project: Protective Device Coordination ETAP Page: 1 5.5.0C Location: WWTP, Bayamon Date: 04-16-2007 Contract: SN: BETA-ELECT Engineer: Hector, Jose, Daniel Revision: Base Study Case: SM Filename: JHD-CS Config.: Normal SHORT- CIRCUIT REPORT Fault at bus: Bus-1 Prefault voltage = 4.160 kV = 100.00 % of nominal bus kV ( 4.160 kV) = 100.00 % of base kV ( 4.160 kV) Positive & Zero Sequence Impedances Contribution 3-Phase Fault Line-To-Ground Fault Looking into "From Bus" From Bus To Bus %V kA % Voltage at From Bus kA Symm. rms % Impedance on 100 MVA base ID ID From Bus Symm. rms Va Vb Vc Ia 3I0 R1 X1 R0 X0 Bus-1 Total 0.00 10.522 0.00 98.93 99.13 10.729 10.729 1.07E+001 1.31E+002 1.05E+001 1.24E+002 BTS-2 Bus-1 0.10 10.522 0.14 98.98 99.09 10.729 10.729 1.07E+001 1.31E+002 1.05E+001 1.24E+002 Bus-2 Bus-1 0.00 0.000 0.00 98.93 99.13 0.000 0.000 BTP-2 BTS-2 94.24 10.522 97.02 100.00 97.14 10.729 10.729 * 1.06E+001 1.31E+002 1.02E+001 1.24E+002 BTP-4 Bus-2 0.00 0.000 0.00 98.93 99.13 0.000 0.000 BTP-6 Bus-2 0.00 0.000 0.00 98.93 99.13 0.000 0.000 Utility 1 BTP-2 100.00 1.152 100.00 100.00 100.00 0.678 0.000 3.79E-001 7.59E+000 BTS-4 BTP-4 0.00 0.000 57.23 57.12 100.00 0.000 0.000 BTS-6 BTP-6 0.00 0.000 57.23 57.12 100.00 0.000 0.000 Bus-1 Bus7 0.00 0.000 0.00 98.93 99.13 0.000 0.000 # Indicates fault current contribution is from three-winding transformers * Indicates a zero sequence fault current contribution (3I0) from a grounded Delta-Y transformer Page 146 of 263
  • Analysis For this system occurred a Three Phase Fault at the bus-1. The systems see the utility impedance, the transformer impedance and the line impedance. For this fault the short circuit is 10,522 A at the bus-1. However when the system occur a Line to Ground Fault we have to consider the zero sequence impedance. The connection for the transformer 1 is Delta-Wye. For this configuration we have to open the second winding at the primary side. The zero sequence is diagram is open by the configuration. For these reason the short circuit current is 10,729 A at the bus-1. Page 147 of 263
  • 4.5.3: Three phase fault at the bus 2 Fig. 4.44: Fault Simulation at Bus 2 of BWWTP *Note: The presented fault is the same at bus 3. Page 148 of 263
  • Fig. 4.45: Sequence of Operation Events at Bus 2 Analysis For this short circuit the device that operates as primary protection is fuse 2. If fuse does not operate, relay (51) will operate as back up with approximately 25 cycles of different to the other coordination. Page 149 of 263
  • Project: Protective Device Coordination ETAP Page: 1 5.5.0C Location: WWTP, Bayamon Date: 04-16-2007 Contract: SN: BETA-ELECT Engineer: Hector, Jose, Daniel Revision: Base Study Case: SM Filename: JHD-CS Config.: Normal SHORT- CIRCUIT REPORT Fault at bus: Bus-2 Prefault voltage = 4.160 kV = 100.00 % of nominal bus kV ( 4.160 kV) = 100.00 % of base kV ( 4.160 kV) Positive & Zero Sequence Impedances Contribution 3-Phase Fault Line-To-Ground Fault Looking into "From Bus" From Bus To Bus %V kA % Voltage at From Bus kA Symm. rms % Impedance on 100 MVA base ID ID From Bus Symm. rms Va Vb Vc Ia 3I0 R1 X1 R0 X0 Bus-2 Total 0.00 9.954 0.00 95.69 102.22 10.176 10.176 1.68E+001 1.38E+002 3.05E+001 1.27E+002 Bus-1 Bus-2 6.65 9.954 8.97 98.87 99.31 10.176 10.176 1.68E+001 1.38E+002 3.05E+001 1.27E+002 BTP-4 Bus-2 0.00 0.000 0.00 95.69 102.22 0.000 0.000 BTP-6 Bus-2 0.00 0.000 0.00 95.69 102.22 0.000 0.000 BTS-2 Bus-1 6.75 9.954 9.10 98.92 99.26 10.176 10.176 1.07E+001 1.31E+002 1.05E+001 1.24E+002 BTS-4 BTP-4 0.00 0.000 59.02 55.25 100.00 0.000 0.000 BTS-6 BTP-6 0.00 0.000 59.02 55.25 100.00 0.000 0.000 BTP-2 BTS-2 94.57 9.954 97.07 100.00 97.42 10.176 10.176 * 1.06E+001 1.31E+002 1.02E+001 1.24E+002 Bus-1 Bus7 6.65 0.000 8.97 98.87 99.31 0.000 0.000 # Indicates fault current contribution is from three-winding transformers * Indicates a zero sequence fault current contribution (3I0) from a grounded Delta-Y transformer Page 150 of 263
  • Analysis The Three Phase failure that occurred at the bus-2 is adding the line impedance three. The short circuit current is 9.954A. When we compare the short circuit at the bus-1 is less because the impedance magnitude has changed. For a Line to Ground Fault the system have the same change in the zero sequence impedance. The systems consider the zero sequence impedance at the line three at this fault. The short circuit current is 10,176 A at the bus-2. Page 151 of 263
  • 4.5.4: Three phase fault at load 1 Fig. 4.46: Fault Simulation at Load 1 of BWWTP *Note: The presented fault is the same at the Loads 2, 4, 5. Page 152 of 263
  • Fig. 4.47: Sequence of Operations Events at Load 1 Analysis A fault at transformer 2 or 3 has a protection in secondary side. Fuse 3 will operates like a back up with 25 cycles of different between primary protection. If fuse 3 does not operate, fuse 2 will operate with 25 cycles different between the fuse 3. Page 153 of 263
  • Project: Protective Device Coordination ETAP Page: 1 5.5.0C Location: WWTP, Bayamon Date: 04-16-2007 Contract: SN: BETA-ELECT Engineer: Hector, Jose, Daniel Revision: Base Study Case: SM Filename: JHD-CS Config.: Normal SHORT- CIRCUIT REPORT Fault at bus: BTS-4 Prefault voltage = 0.480 kV = 100.00 % of nominal bus kV ( 0.480 kV) = 100.00 % of base kV ( 0.480 kV) Positive & Zero Sequence Impedances Contribution 3-Phase Fault Line-To-Ground Fault Looking into "From Bus" From Bus To Bus %V kA % Voltage at From Bus kA Symm. rms % Impedance on 100 MVA base ID ID From Bus Symm. rms Va Vb Vc Ia 3I0 R1 X1 R0 X0 BTS-4 Total 0.00 35.438 0.00 92.90 93.28 41.060 41.060 4.47E+001 3.36E+002 2.79E+001 1.98E+002 BTP-4 BTS-4 58.93 35.438 77.20 100.00 77.66 41.060 41.060 * 4.47E+001 3.36E+002 2.79E+001 1.98E+002 Bus-2 BTP-4 58.93 4.089 77.20 100.00 77.66 2.735 0.000 1.79E+002 7.10E+001 Bus-1 Bus-2 61.22 4.089 77.73 100.00 79.48 2.735 0.000 1.79E+002 7.10E+001 BTP-6 Bus-2 58.93 0.000 77.20 100.00 77.66 0.000 0.000 Bus-1 Bus7 61.22 0.000 77.73 100.00 79.48 0.000 0.000 # Indicates fault current contribution is from three-winding transformers * Indicates a zero sequence fault current contribution (3I0) from a grounded Delta-Y transformer Page 154 of 263
  • Analysis A Three Phase Fault is happened in the secondary side of the transformer 7 (BTS-12). The transformer capacity is 0.15 MVA and the connection is Delta-Wye. The impedance viewed at this point is by the utility, two transformers and lines. The short circuit current is 6,687A. When the Line to Ground Fault occur the zero sequence impedance is open by the primary side of the transformer 7 (BTS-12). The short circuit current at the secondary side of the transformer is 6,855A. Page 155 of 263
  • 4.5.5: Three phase fault at Load 6 Fig. 4.48: Fault Simulation at Load 6 of BWWTP Page 156 of 263
  • Fig. 4.49: Sequence of Operation Events at Load 6 Analysis Transformer 7 has a protection in the secondary side as a protection to faults as showing above. Fuse 9 will operates like a back up with 9 cycles of different between primary protection. Page 157 of 263
  • Project: Protective Device Coordination ETAP Page: 1 5.5.0C Location: WWTP, Bayamon Date: 04-16-2007 Contract: SN: BETA-ELECT Engineer: Hector, Jose, Daniel Revision: Base Study Case: SM Filename: JHD-CS Config.: Normal SHORT- CIRCUIT REPORT Fault at bus: BTS-12 Prefault voltage = 0.480 kV = 100.00 % of nominal bus kV ( 0.480 kV) = 100.00 % of base kV ( 0.480 kV) Positive & Zero Sequence Impedances Contribution 3-Phase Fault Line-To-Ground Fault Looking into "From Bus" From Bus To Bus %V kA % Voltage at From Bus kA Symm. rms % Impedance on 100 MVA base ID ID From Bus Symm. rms Va Vb Vc Ia 3I0 R1 X1 R0 X0 BTS-12 Total 0.00 6.687 0.00 98.84 98.70 6.855 6.855 9.45E+001 1.80E+003 8.32E+001 1.66E+003 BTP-12 BTS-12 92.65 6.687 96.34 100.00 96.18 6.855 6.855 * 9.45E+001 1.80E+003 8.32E+001 1.66E+003 Bus6 BTP-12 92.67 0.772 96.33 100.00 96.20 0.457 0.000 8.97E+002 1.56E+002 BTS-3 Bus6 92.68 0.772 96.34 100.00 96.21 0.457 0.000 8.96E+002 1.56E+002 Bus-3 Bus6 92.67 0.000 96.33 100.00 96.20 0.000 0.000 Bus10 Bus6 92.67 0.000 96.33 100.00 96.20 0.000 0.000 # Indicates fault current contribution is from three-winding transformers * Indicates a zero sequence fault current contribution (3I0) from a grounded Delta-Y transformer Page 158 of 263
  • Analysis A Three Phase Fault is happened in the secondary side of the transformer 7 (BTS-12). The transformer capacity is 0.15 MVA and the connection is Delta-Wye. The impedance viewed at this point is by the utility, two transformers and lines. The short circuit current is 6,687A. When the Line to Ground Fault occur the zero sequence impedance is open by the primary side of the transformer 7 (BTS-12). The short circuit current at the secondary side of the transformer is 6,855A. Page 159 of 263
  • 4.6 Power Fuses Selection for Power Transformers T1, T2, T3, T4, T5, T6 and T7 Page 160 of 263
  • V. Protective Device Selection A. Power Fuses Selection Power Transformers T1, T2, T3, T4, T5, T6 and T7 The Power Fuse Time Coordination show the analysis for the short circuit simulations at the utility side and the power plant side for the T1, T2, T3, T4, T5, T6 and T7. The fuse coordination complies with time (12-30cycles) permitted by each coordination. The following table shows the power fuse summary for the transformers. # Power Transformer Recommended Power Fuse Curve 1 T1 38/4.16 SMD-2C-100E Slow Speed 2 T2 4.16/0.48 SMU-40-300E Slow Speed 3 T3 4.16/0.48 SMU-40-300E Slow Speed 4 T4 38/4.16 SMD-2C-100E Slow Speed 5 T5 4.16/0.48 SMU-40-300E Slow Speed 6 T6 4.16/0.48 SMU-40-300E Slow Speed 7 T7 4.16/0.48 SMU-40-30E STD Speed 8 Main Feeder Fault Fiter-600 Time-delayed Fig. 4.50: Recommendations to Fuse Protection *Note: The fuse curves are in the appendix. Page 161 of 263
  • Treatment power Plant Power Transformer 1-2 Time Fuse Coordination Project: Bayamón Waste Water Treatment Plant Voltage (kV): 38/4.16 Connection (Type): DELTA-WYE Capacity (MVA): 5 Impedance (Z%): 6.21 @ 5 MVA IFL (Amps High Side): 76.05 @ 5 MVA IINRUSH CURRENT = (IFL *12): 912.16 ISC (AEE): 20,000 Fig. 4.51: Time Fuse 1 and 5 Coordination Page 162 of 263
  • Fig. 4.52: Characteristics Curves for Fuse 1 and 5 The fuse chosen has the capacity to break the short circuit at 0.475 A or 28.5 cycles. Page 163 of 263
  • S&C SMD-2C The next figures show the operation of different fuses by ours recommendation and alternatives options. The fuses are operating like a back up protection to accomplish to our protection criteria. Curve Fuse 65E 80E 100E 125E 150E STD Speed Minimum 4.39 9.28 10.92 18.06 27.00 Melting Time Total clearing 8.52 11.58 16.50 24.78 36.06 Time Curve Fuse 65E 80E 100E 125E 150E Slow Speed Minimum 7.02 12.12 20.58 33.30 51.48 Melting Time Total clearing 11.70 17.82 28.32 44.28 67.32 Time Curve Fuse Recommended Slow Speed 100 E Fuse Fig. 4.53: Fuse 1 and 5 recommended Alternative STD Speed 125 E Fuse Page 164 of 263
  • Treatment power Plant Main Feeder Time Fuse Coordination Project: Power Treatment Plant Voltage (kV): 4.16 IFL (Amps High Side): 416.85 Fig. 4.54: Time Fuse 2 and 6 Coordination Page 165 of 263
  • Fig. 4.55: Characteristics Curves for fuse 2 and 6 The fuse chosen has the capacity to break the arch at 0.84s or 50.4 cycles. Fault Fiter The fault fiter fuse has the same curves for the other fusible. That makes the option to select the best operation time in the case that has to operate the fuse Curve Fuse 400 600 Time Delayed Minimum 22.62 43.8 Melting Time Total clearing 26.34 50.4 Time Fig. 4.56: Fuse 2 and 6 Recommended Page 166 of 263
  • Treatment power Plant Power Transformer 2-3, 5-6 Time Fuse Coordination Project: Power Treatment Plant Voltage (kV): 4.16/0.48 Connection (Type): DELTA-WYE Capacity (MVA): 1.5 Impedance (Z%): 3 @ 1.5 MVA IFL (Amps High Side): 208.45 @ 1.5 MVA IINRUSH CURRENT = (IFL *12): 2,501.45 Fig. 4.57: Time Fuse 3, 4, 7 and 8 Coordination Page 167 of 263
  • Fig. 4.58: Characteristics Curves for fuses 3, 4, 7 and 8 The fuse selected has the capacity to break the arch at 0.395s or 23.7 cycles. Page 168 of 263
  • S&C SMU-40 The next figures show the operation of different fuses by ours recommendation and alternatives options. The fuses are operating like a back up protection to accomplish to our protection criteria. Curve Fuse 200E 250E 300E 400E STD Speed Minimum 3.27 4.65 7.14 11.76 Melting Time Total clearing 7.20 8.88 14.28 20.22 Time Curve Fuse 200E 250E 300E 400E Slow Speed Minimum 6.72 10.20 14.94 24.96 Melting Time Total clearing 11.40 15.54 23.76 33.36 Time Curve Fuse Recommended Slow Speed 300 E Fuse Alternative STD Speed 400 E Fig. 4.59: Fuse 3, 4, 7 and 8 Recommended Fuse Page 169 of 263
  • Treatment power Plant Power Transformer 7 Time Fuse Coordination Project: Power Treatment Plant Voltage (kV): 4.16/0.48 Connection (Type): DELTA-WYE Capacity(MVA): 0.15 Impedance (Z%): 2,5 @ 0.15 MVA IFL (Amps High Side): 20.84 @ 1.5 MVA IINRUSH CURRENT = (IFL *12): 250.11 Fig. 4.60: Time Fuse 9 Coordination Page 170 of 263
  • Fig. 4.61: Characteristics Curves for fuse 9 The fuse chosen has the capacity to break the short circuit at 0.155s or 9.30 cycles. Page 171 of 263
  • S&C SMU-40 The next figures show the operation of different fuses by ours recommendation and alternatives options. The fuses are operating like a back up protection to accomplish to our protection criteria. Curve Fuse 20E 25E 30E 40E 50E STD Speed Minimum 1.08 1.75 2.15 3.53 5.27 Melting Time Total clearing 6.66 7.50 7.98 9.66 11.76 Time Curve Fuse 20E 25E 30E 40E 50E Slow Speed Minimum 1.40 1.86 3.24 6.66 10.80 Melting Time Total clearing 7.08 7.62 9.30 13.44 18.40 Time Curve Fuse Recommended Slow Speed 30 E Fuse Fig. 4.60: Fuse 9 Recommended Alternative STD Speed 40 E Fuse Page 172 of 263
  • 4.7 Protection Relay Settings for Distribution Feeders Page 173 of 263
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  • 4.8 Relay Settings Page 178 of 263
  • Relay 351A: Relay 351A Operation Protection Devices Element Pick-up Extremely Inverse Curve M TD 51 816 A 12.19 4.67 50 10,104 A X X Extremely Inverse Curve 51N 278 A 37.25 8.53 50N 10,104 A X X Directional Power Relay Pick-up (pu) Time 32 0.57 0.5 Fig. 4.63: Relay 351A Settings After finish all necessary calculations by hand to reach al requirements of coordination using 23 to 25 cycles between coordinaion levels we found setings specifications for Relay 351A. These setting are shown above. The coordination was performed with ETAP software. Relay 351A is used for protect transformer 1 an 2. The elements in the relay are 50, 51, 50N, 51N, 32. Page 179 of 263
  • Relay 300G: Relay 300G Operation Protection Devices Element Pick-up Extremely Inverse Curve M TD 51 416.84 A 188.47 8.48 50 80,000 A X X Extremely Inverse Curve 51N 138.95 A 565.39 8.52 50N 80,000 A X X Fig. 4.64: Overcurent Relay Settings for Generator Relay 300G Operation Protection Devices Element Voltage Under voltage Overvoltage 27/59 4,160 V 4,035 V 4,285 V Frequency Relay Frequency Over Frequency Under Frequency 81 60 Hz 61.2 Hz 58.8 Hz Fig. 4.65: Undervoltage, Overvoltage, Frequency of Power Relay for Generator Relay 300G is used to protect generator. The relay components are overcurrent protection (50, 51, 50N, 51N), overvoltage (59) and underoltage (27), frequency protection (81). After finish calculations with necessary coordination levels and criteria we select the settings presented in tables above. Page 180 of 263
  • 4.9 Results Page 181 of 263
  • Results We realized a three phase fault through BWWTP power system using PREPA connection. Our evaluation criteria to all faults were 23 to 25 cycles of difference between coordination levels. Figure 4.60 shows the short circuits magnitudes at the points analyzed. It also includes operation time for each equipment. Page 182 of 263
  • Fault using the utility: Three Phase Fault Operating Short Localization Voltage Circuit Operation Protection Devices Time (Cycles) Fault (kV) Current Fuse1/5 Fuse2/6 Fuse3/4/7/8 Fuse9 Relay(50) Relay(51) T1, T4 Primary 38 20,000A 1.44 -------- -------- -------- -------- -------- T1, T4 4.16 10,504 A 44.70 -------- -------- -------- -------- -------- Secondary Bus1, Bus 6 4.16 10,500 A 44.82 -------- -------- -------- 0 19.5 Bus2, Bus 3 4.16 9,950 A 49.62 1.62 -------- -------- -------- 23.64 T2, T3, T5, T6 4.16 9,950 A -------- 1.62 5.88 -------- -------- 23.64 Primary T2, T3, T5, T6 0.48 35,440 A -------- 50.4 23.76 -------- -------- 75.78 Secondary T7 Primary 4.16 9,950 A 49.62 1.62 -------- -------- -------- 23.64 T7 Secondary 0.48 6,690 A -------- -------- -------- 7.98 -------- -------- Fig. 4.66: Three Phase Fault Results Page 183 of 263
  • The figure below shows line to ground fault at different areas of system. This kind of fault change operation time of devices. However, protective device coordination still working the same. All points reach coordination criteria of 23 to 25 cycles between coordination levels. Results was verified with manual calculations and using ETAP software. Line to ground Fault Operating Short Localization Voltage Circuit Operation Protection Devices Time (Cycles) Fault (kV) Current Fuse 1/5 Fuse 2/6 Fuse 3/4/7/8 Fuse 9 Relay(50) Relay(51) T1, T4 Primary 38 0A -------- -------- -------- -------- -------- -------- T1, T4 4.16 0A -------- -------- -------- -------- -------- -------- Secondary Bus1, Bus 6 4.16 10,730 A -------- -------- -------- -------- 0 23.10 Bus2, Bus 3 4.16 10,180 A -------- 1.62 -------- -------- 0 23.10 T2, T3, T5, T6 4.16 10,180 A -------- 1.62 5.7 -------- -------- 23.10 Primary T2, T3, T5, T6 0.48 41,060 A -------- -------- 48.78 -------- -------- -------- Secondary T7 Primary 4.16 10,730 A -------- -------- -------- -------- 0 23.10 T7 Secondary 0.48 6,850 A -------- -------- -------- 14.34 -------- -------- Fig. 4.67: Line to Ground Fault Results Page 184 of 263
  • When Bayamón WWTP is working with generators is possible that faults could happen. For that reason we made protective device coordination for BWWTP using generators. For a three phase fault at generators the overcurrent relay operates. If a fault occurs in system far from generators, protective devices work faster than when using utility. It reduces time between coordination devices. Coordination results are showing in table below. Fault using the generators: Three Phase Fault Operated Localization Short Circuit Voltage Operation Protection Devices Time (Cycles) Fault Current (kV) Fuse Fuse Fuse Fuse 9 RelayG(50) RelayG(51) 1/5 2/6 3/4/7/8 Bus1, Bus 6 4.16 258,532.1 A -------- -------- -------- 0 0 17.91 Bus2, Bus 3 4.16 112,864.33 A -------- 0 -------- -------- -------- 18.06 T2, T3, T5, T6 0.48 56,673.16 A -------- 0.78 5.4 -------- -------- 65.58 Secondary T7 Secondary 0.48 7,193.37 A -------- -------- -------- 1.8 -------- -------- Fig. 4.68: Three Phase Fault Results Using Generators. Line to ground Fault Localization Operated Short Circuit Fault Voltage Current Operation Protection Devices Time (Cycles) (kV) Fuse 1/5 Fuse 2/6 Fuse Fuse 9 Relay(50) Relay(51) 3/4/7/8 336,678,51 A -------- -------- -------- 0 0 18.0 Bus1, Bus 6 4.16 140,244.95 A -------- 0 -------- -------- -------- 18.0 Bus2, Bus 3 4.16 T2, T3, T5, T6 57,815.87 A -------- 33.6 5.58 -------- -------- 33.6 0.48 Secondary T7 Secondary 7,164.46 A -------- -------- -------- 1.8 -------- -------- 0.48 Fig. 4.69: Line to Ground Fault Results Using Generators Page 185 of 263
  • Chapter 5: Protective Device Coordination Project Results Page 186 of 263
  • Contents Alternatives Considered…………………………………………………………………. 188 System Specification…………………………………………………………………….. 190 Magazine Article………………………………………………………………………… 195 Budget…………………………………………………………………………………… 196 Bibliography……………………………………………………………………………... 197 Conclusions……………………………………………………………………………… 199 Page 187 of 263
  • 5.1 Alternatives Considered Through the capstone project appears many questions with multiple solutions. That moved us to realize brainstorming to find the best way of action. We analyzed each possible solution as a great alternative and visualized their advantages and disadvantages. Then, we chose the best answer. There is a summary of alternatives considered. I. Protective Devices There are a lot of protective devices at market today. It gives us many alternatives to considered. However, to choose a protective device, first we have to look system capacity, localization and kind of charge connected to it. II. Manufacturer Selection Every manufacturer offers different protective devices to perform the same thing in a power system. For that reason we have a lot of alternatives about which protective device should be used. Each device does not work at same way. According to this, we prefer to use most commonly used manufacturers and devices in Puerto Rico. III. Compatibility of Devices As part of protective device coordination each protective device has to work as a team with other devices. But, unfortunately, some devices are not compatible with devices produced by others manufacturers. It force us to considerate the alternative of use devices of same manufacturer of existing devices in power system. If we do not considered this alternative, protective device coordination will not be complete. IV. Fault Analysis There are many things that could make a system fault. In field of power system, these faults are classified in four categories. These are: phase to phase, single phase to ground, double phase to ground and, three phase fault. A fault can occur everywhere at any time. Also, is possible that occur more than once at in power system at the same Page 188 of 263
  • time. Is very important remember this detail. If we do it, then we could realize a better contingency, which means best protective device coordination. In our design the short circuit study give us the information to select the appropriate protective devices. With the faults magnitude in the different parts of the system our devices operates with our coordination criteria (23 to 25 cycles) and protect the equipments of damage. V. User Guide: a. One user guide. The option of write only one user guide was very tempting. It represents less work for us. But, write one manual with an explanation of all elements in program, data required, and possible mistakes made by user, could make it too long. A long user guide can make that people do not want to read it. Also, we thought in busy engineers who do not have time to read a long manual. They need something short and easy to read. For that reason we discard the idea. b. Two user guides. We realized the idea of create two user guides, basic one and advance one. The basic user guide has the purpose of give an explanation step by step of how to use ETAP program. It covers from how to build a one-line diagram to how to perform a short circuit analysis. Also, this guide is written to be easy to read and understand. Busy engineers can perform a power system simulation fast and without problem. At this time, we thought that some people may ask for more information. For them, we prepared a second user guide, an advance user guide. In this guide we give more specific details of some features of ETAP program. For example, we include a case study solution as a model of how made a simulation with program. Also, it includes equipment data requirements, and technical terms uses by ETAP software. Page 189 of 263
  • We chosen this second alternative, because we understand it is more practical for today’s engineers. Page 190 of 263
  • 5.2 System Specifications Circuit Breaker A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear designed to protect high voltage circuits feeding an entire city. Fig. 5.1: Vacuum Circuit Breaker Fuse In electronics and electrical engineering a fuse, short for 'fusible link', is a type of overcurrent protection device. Its essential component is a metal wire or strip that melts when too much current flows. When the metal strip melts, it opens the circuit of which it's a part, and so protects the circuit from excessive current. A practical fuse was one of the essential features of Edison's electrical power distribution system. An early fuse was said to have successfully protected an Edison installation from tampering by a rival gas-lighting concern. Fuses (and other overcurrent devices) are an essential part of a power distribution system to prevent fire or damage. When too much current flows through a wire, it may overheat and be damaged or even start a fire. Wiring regulations give the maximum rating of a fuse for protection of a particular circuit. Local authorities will incorporate national wiring Page 191 of 263
  • regulations as part of law. Fuses are selected to allow passage of normal currents, but to quickly interrupt a short circuit or overload condition. Fig. 5.2: Power Fuse Relay A relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered to be, in a broad sense, a form of an electrical amplifier. Fig. 5.3: Protective Relay Page 192 of 263
  • Operation When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned by a force approximately half as strong as the magnetic force to its relaxed position. Usually this is a spring, but gravity is also used commonly in industrial motor starters. Most relays are manufactured to operate quickly. In a low voltage application, this is to reduce noise. In a high voltage or high current application, this is to reduce arcing. If the coil is energized with DC, a diode is frequently installed across the coil, to dissipate the energy from the collapsing magnetic field at deactivation, which would otherwise generate a spike of voltage and might cause damage to circuit components. Some automotive relays already include that diode inside the relay case. Alternatively a contact protection network, consisting of a capacitor and resistor in series, may absorb the surge. If the coil is designed to be energized with AC, a small copper ring can be crimped to the end of the solenoid. This "shading ring" creates a small out-of-phase current, which increases the minimum pull on the armature during the AC cycle. By analogy with the functions of the original electromagnetic device, a solid-state relay is made with a thyristor or other solid-state switching device. To achieve electrical isolation an optocoupler can be used which is a light-emitting diode (LED) coupled with a photo transistor. Protective relay A protective relay is a complex electromechanical apparatus, often with more than one coil, designed to calculate operating conditions on an electrical circuit and trip circuit breakers when a fault was found. Unlike switching type relays with fixed and usually ill- defined operating voltage thresholds and operating times, protective relays had well- established, selectable, time/current (or other operating parameter) curves. Such relays were very elaborate, using arrays of induction disks, shaded-pole magnets, operating and Page 193 of 263
  • restraint coils, solenoid-type operators, telephone-relay style contacts, and phase-shifting networks to allow the relay to respond to such conditions as over-current, over-voltage, reverse power flow, over- and under- frequency, and even distance relays that would trip for faults up to a certain distance away from a substation but not beyond that point. An important transmission line or generator unit would have had cubicles dedicated to protection, with a score of individual electromechanical devices. The various protective functions available on a given relay are denoted by standard ANSI Device Numbers. For example, a relay including function 51 would be a timed overcurrent protective relay. These protective relays provide various types of electrical protection by detecting abnormal conditions and isolating them from the rest of the electrical system by circuit breaker operation. Such relays may be located at the service entrance or at major load centers. Design and theory of these protective devices is an important part of the education of an electrical engineer who specializes in power systems. Today these devices are nearly entirely replaced (in new designs) with microprocessor-based instruments (numerical relays) that emulate their electromechanical ancestors with great precision and convenience in application. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these "silent sentinels" are still protecting transmission lines and electrical apparatus all over the world. Overcurrent relay An "Overcurrent Relay" is a type of protective relay which operates when the load current exceeds a preset value. The ANSI Device Designation Number is 50 for an Instantaneous OverCurrent (IOC), 51 for a Time OverCurrent (TOC). In a typical application the overcurrent relay is used for overcurrent protection, connected to a current transformer and calibrated to operate at or above a specific current level. When the relay Page 194 of 263
  • operates, one or more contacts will operate and energize a trip coil in a Circuit Breaker and trip (open) the Circuit Breaker. Distance relay It is a protective relay used to protect power transmission and distribution lines against different fault types. The relay monitors line impedance by measuring line voltage and current. Once a fault occurs, the voltage drops to zero and thus the measured impedance become less than the setting value ``reach``. As a result the relay issues a trip command. Transformer A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled wires. A changing current in the first circuit (the primary) creates a changing magnetic field; in turn, this magnetic field induces a changing voltage in the second circuit (the secondary). By adding a load to the secondary circuit, one can make current flow in the transformer, thus transferring energy from one circuit to the other. The secondary induced voltage VS is scaled from the primary VP by a factor ideally equal to the ratio of the number of turns of wire in their respective windings: By appropriate selection of the numbers of turns, a transformer thus allows an alternating voltage to be stepped up — by making NS more than NP — or stepped down, by making it less. A key application of transformers is to reduce the current before transmitting electrical energy over long distances through wires. Most wires have resistance and so dissipate electrical energy at a rate proportional to the square of the current through the wire. By transforming electrical power to a high-voltage, and therefore low-current form for transmission and back again afterwards, transformers enable the economic transmission Page 195 of 263
  • of power over long distances. Consequently, transformers have shaped the electricity supply industry, permitting generation to be located remotely from points of demand. All but a fraction of the world's electrical power has passed through a series of transformers by the time it reaches the consumer. Transformers are some of the most efficient electrical 'machines', with some large units able to transfer 99.75% of their input power to their output. Transformers come in a range of sizes from a thumbnail-sized coupling transformer hidden inside a stage microphone to huge units weighing hundreds of tones used to interconnect portions of national power grids. All operate with the same basic principles, though a variety of designs exist to perform specialized roles throughout home and industry. ETAP Software This software is designed to perform power system simulations. It is a very advance program capable to simulate most of power system analysis. Unfortunately, it is a little hard to understand. To run the software you need at least 1 Mb RAM processor with Windows XP or higher. Page 196 of 263
  • Magazine Article Page 197 of 263
  • 5.4 Budget Table A. Materials required developing the data base Amount Description Price p/u Total 1 Laptop $800.00 $800.00 1 ETAP software $4000.00 $4000.00 1 Logbook $23.00 $23.00 Total $4823.00 Table B. Professional Service Cost Job Title Number of Salary per Weekly Monthly 6 Month Employers Hour Hours Hours Salary Research & Development 3 $15.00 15 60 $16,200 Team Page 198 of 263
  • 5.5 Bibliography • Power System Protection, [Online]. Available: http://en.wikipedia.org/wiki/Protection_and_monitoring_of_the_electrical_energy_t ransmission_networks • Electrical Engineering History, [Online]. Available: http://www.history.com/encyclopedia.do?articleId=208367 • Electricity, [Online]. Available: http://www.eia.doe.gov/kids/history/timelines/electricity.html • Short Circuit Analysis, [Online]. Available: http://www.answers.com/topic/short- circuit?cat=technology • General Electric: (www.ge.com/products_services/electrical_distribution.html). • ABB: (http://www.abb.com/ProductGuide/Alphabetical.aspx) • Cutler Hammer: (http://www.eaton.com/EatonCom/Markets/Electrical/Products/SwitchingDevicesan dDisconnects/EnclosedCircuitBreakers/index.htm) • Siemens: (http://w1.siemens.com/en/us/entry.html) • Square D: (http://www.squared.com/us/squared/corporate_info.nsf/unid/ECA90110AB7098C A85256A3A007091D7/$file/productsa2zFrameset.htm) • ETAP Program, [Online] Available: www.etap.com • International Electric Power Encyclopedia, 1998 Per Wel, Publishing Company, Tulas, UK. • International Electric Power Encyclopedia, 1999 Per Wel, Publishing Company, Tulas, UK. • Zaberszky, John; Rittenhouse, Joseph W.; Electric Power Transmission, The Ronald Press Company, 1954. • T. Davies C., Protection of Industrial Power Systems; Pergamon Press, 1984. • Duncan Glober, J.; Sarma Mulukutla; Power System Analysis and Design; PWS- KENT Publishing Company, Boston. • Anderson, P.M.; Power System Protection; McGraw Hill, 1998. Page 199 of 263
  • • Circuit Breakers, suitehged, substations and fuses, Ed. 1995; IEEE standards Collection. Page 200 of 263
  • 5.6 Conclusion In this project we work with computer software, called ETAP, to analyze the protection coordination of an electrical design. We started analyzing and searching information about how to use the program. We prepared two User guides to help in the use and comprehension of the program. Our purpose was preparing something easy for reading and understanding. When the user guide was complete, we make an example design and utilize the program to corroborate the protective device coordination of the power system. In the final part, we analyzed a new design, a real develop. All the coordination of the system was make manually and in the ETAP program. Page 201 of 263
  • Chapter 6: Administrative Section Page 202 of 263
  • Contents Protective Device Coordination Project Proposal……………………………………….. 203 Capstone Design 1 Proposal Presentation….…………………………………………..... 214 Progress Report………………………………………………………………………….. 220 Work Schedule…………………………………………………………………………... 239 Page 203 of 263
  • Table of Figures Fig. 6.1: Protective Devices……………………………………………………………... 213 Fig. 6.2: Budget to Complete Design…………………………………………………… 218 Fig. 6.3: Salary Cap……………………………………………………………………... 218 Page 204 of 263
  • 6.1 Protective Device Coordination Project Proposal Page 205 of 263
  • POYTECHNIC UNIVERSITY OF PUERTO RICO ELECTRICAL ENGINEERING DEPARTMENT HATO REY, PUERTO RICO CAPSTONE DESIGN COURSE 1 EE 5002 - 22 PROF. ASDRUBAL MORALES COLÓN PROPOSAL PROTECTIVE DEVICE COORDINATION GROUP 28 Laporte Plaza, Daniel J. 0108949 Pagán Hernández, José A. A0000002020 Rivera Alejandro, Héctor J. 0109470 SEPTEMBER 25, 2007 Page 206 of 263
  • Problem Definition The power protection analysis is one of the main criteria’s in the electrical design. Different kinds of programs have been created to analyze the coordination of protection in electrical systems. Some of protection programs do not provide a database with sufficient information about relays and others protection equipments. In our project we will work to improve the database of an existent program. Searching information about different power relays, fuses and other protection mechanism we will work to analyze the behavior of these and improve the database of the program. The equipments utilized in electric system are very expensive. The electrical systems must be very reliable and the protection of these is one of the principle fields in electrical engineering. Our projects talks about different topics in electrical engineering like protection coordination, database for programs, power engineering, power relays, protection equipment and others fields in power. Page 207 of 263
  • Introduction Electricity has been a subject of scientific interest since at least the early 17th century. Probably the first electrical engineer was William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity. However it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise on Electricity and Magnetism. They are the fathers of electrical engineering and the electric systems. Today, power system protection is that part of electrical power engineering that deals with protecting the electrical power system from faults by isolating the faulted part from the rest of the network. Any electric-distribution system involves a large amount of supplementary equipment for the protection of generators, transformers, and the transmission lines. Circuit breakers are employed to protect all elements of a power system from short circuits and overloads, and for normal switching operations. The principle of a protection scheme is to keep the power system stable by isolating only the components that are under fault, even as leaving as much of the network as possible still in operation. Thus, protection schemes must apply a very pragmatic and pessimistic approach to clearing system faults. For this reason, the technology and philosophies utilized in protection schemes are often old and well-established because they must be very reliable. In much the same way as the early computers of the 1950s and 1960s were a precursor to the computational capabilities of today’s computers. Specialized hardwire systems were developed for locally monitoring the operation of power plants and for remotely monitoring and controlling switches in transmission substation. The Remote Terminal Units of these early monitoring systems were implemented with relay logic, while the master station consisted primarily of large banks of annunciator panels with red and green light indication Page 208 of 263
  • the state of the points being monitored with flashing light indication a change in state or an alarm condition. The impact of computers has nowhere been more revolutionary than in electrical engineering. The design, analysis and operation of electrical and electronic systems has become completely dominated by computers, a transformation that has been motivated by the natural ease of interface between computers and electrical systems, and the promise of spectacular improvements in speed and efficiency. Our project consists of develop a protective device coordination using a graphical software program to add features and flexibility in the area of electrical system protection. Also, this graphical software program it’s going to be using for all kind of element that used these. We will select the software program, analyze all types of element protection that are utilizing in electrical systems, and simulate the program using various management studies. Page 209 of 263
  • Objectives • To make a research about technical references of fuses, relays and breakers. • Understand technical data format of protection devices. • To learn how to use the protective device coordination program. • Create the database of a graphical software program. • Build a library to graphical system to represent every fuses, relay and breaker. • Perform a case study with the improved software program. • Establish the system coordination of a case study with the improved program. Page 210 of 263
  • Constraints • Ways to use library of ETAP program. Start by understanding. • How to create the monolineal diagram of the design in this program. • Method on building the protection diagram of it design. • Understand how to work a short circuit test in the program. • Interpret results in the program to establish the coordination of a protection system. • Run the program with all kind of requisites. Page 211 of 263
  • Expected Results • Find the technical data of relays, fuses and breakers. • Understand clearly the operation of the protection devices. • Domain the use program to perform analyze of the system. • Create a set of easy drawings to selection with the system protection symbols. • Improve the graphic system with the greatest quantity of protective equipment. • Develop a case study with the program completely improved. • Expand database to allow user realize a simulation with the most parts of the equipment available in market. • Prepare the protection coordination of an electric design and test it, in the program. Page 212 of 263
  • Procedure 1. Search information about relays. 2. Make a research of breakers. 3. Find information about fuses. 4. Understand most of concepts of power system protection. 5. Learn how to perform a short circuit analysis. 6. Create a suppliers list. 7. Understand technical data format of the operation mechanism of relays. 8. Comprehend operation mechanism of breakers. 9. Know how work fuses. 10. Obtain program to work with the protection systems. 11. Learn how to use the program. 12. Discover the way to create a database. 13. Develop a database with the available information. 14. Create a library with the graphic system of protection equipment. 15. Perform the mathematic justification of a case study. 16. Make a drawing of an electrical design. 17. Perform a short circuit analysis with the computer program. 18. Realize the protection coordination justification of the design. 19. Create protection coordination with the computer program. 20. Prepare tables of coordinate studies. Page 213 of 263
  • Design Specifications Improve an existing power system program to make these most efficient. The work will consist in develop the database of the program and establish protection coordination of any scheme protection. In addition, it will include a created electrical design to make a short circuit test to prove it. Relay Hardware The relay hardware for electronic relays consists of both analog and digital devices. The input signals are analog and require, at very minimum, a conversion to digital form. Therefore, the relays design is often a mixture of analog electronic devices and digital hardware. The relays may also contain transformers or other components that are also found in electromagnetic and electromechanical protective devices. Induction relays are available in many variations to provide accurate pickup and time- current responses for a wide range of simple or complex system conditions. Induction relays are basically induction motors. The moving element, or rotor, is usually a metal disk, although it sometimes may be a metal cylinder or cup. Electronic relays require less power to operate than their mechanical equivalents, producing a smaller load burden on the CT’s and PT’s that supply them. The most frequently used relay is the over current relay, combining both instantaneous and inverse-time tripping functions. Page 214 of 263
  • Over current Relays Fig. 6.1: Protective Devices Protective Devices The protective system device usually consists of several elements that are arranged to test the system condition, make decision regarding the normally of observed variables, and take action as required. Over current time unit have characteristics such that its operation time vary inversely with the current flow in the relay. These characteristics are available generally in three types of curves, Inverse, Very Inverse, and Extremely Inverse. Other protective device is fuses. Fuses are designed for many different applications and with variety of characteristics to meet the requirements both routine and special situations. Fuses have different curves to realize these requirements. The minimum melting curve is an average melting time measured in low voltage test where arcing does not occur. Other curve is total clearing curve should be used in coordinating against the minimum melting characteristics of a larger fuse, located toward the power source. Distribution fuses links are given voltage ratings of 7.2, 14.4, and 17 KV nominal, or 7.8, 15, and 18 KV maximum for use in open-link cutouts. Page 215 of 263
  • Computer Engineering The Power-flow computer program is the basic tool for investigating power system operation requirement. Power-flow programs compute the voltage magnitudes, phase angles, and transmission- line power flows for a network under steady-state operating conditions. The computers have sufficient networks for more than 200 buses and 2500 transmission lines. Short circuit programs are used to compute three-phase and line-to- ground faults in power- systems network in order to select circuit breakers for fault interruption, select relays that detect faults and control circuit breakers and determine the relay settings. Short-circuit currents are computed for each relay and circuit breaker location, and for various system-operation conditions such as lines or generating units out of service, in order to determine minimum and maximum fault currents. ETAP Program ETAP seamlessly integrates the analysis of power control circuits within one electrical analysis program. The control system diagram simulates the sequence of the operation control devices such as solenoids, relays, controlled contacts multi-sequence contacts and actuators including inrush conditions. The control system diagram has the capability of determine pick-up and dropout voltage, losses and current flows at any time instance as well as overall margin and critical alerts. A large library of equipment enables engineers to quickly model and simulate the action of relays associate with the control interlocks after given time delays. Page 216 of 263
  • Work Schedule Page 217 of 263
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  • Budget Table A. Materials required developing the data base Amount Description Price p/u Total 1 Laptop $800.00 $800.00 1 ETAP software $4000.00 $4000.00 1 Logbook $23.00 $23.00 Total $4823.00 Fig. 6.2: Budget to Complete Design Table B. Professional Service Cost Job Title Number of Salary per Weekly Monthly 6 Month Employers Hour Hours Hours Salary Research & Development 3 $15.00 15 60 $16,200 Team Fig. 6.3: Salary Cap Page 220 of 263
  • References • [Online]. Available: http://en.wikipedia.org/wiki/Protection_and_monitoring_of_the_electrical_energy_t ransmission_networks • [Online]. Available: http://www.history.com/encyclopedia.do?articleId=208367 • [Online]. Available: http://www.eia.doe.gov/kids/history/timelines/electricity.html • [Online]. Available: http://www.answers.com/topic/short-circuit?cat=technology • General Electric: (www.ge.com/products_services/electrical_distribution.html). • ABB: (http://www.abb.com/ProductGuide/Alphabetical.aspx) • Cutler Hammer: (http://www.eaton.com/EatonCom/Markets/Electrical/Products/SwitchingDevicesan dDisconnects/EnclosedCircuitBreakers/index.htm) • Siemens: (http://w1.siemens.com/en/us/entry.html) • Square D: (http://www.squared.com/us/squared/corporate_info.nsf/unid/ECA90110AB7098C A85256A3A007091D7/$file/productsa2zFrameset.htm) Page 221 of 263
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  • Tables and Curves Page 247 of 263
  • Fig. A.1: NEC Fuse Table Our design was performed considering NEC requirements. Page 248 of 263
  • Relays Setting Calculations: Multiple Curve: Fig. A.2: Relay Extremely Inverse Curve Page 249 of 263
  • Fig. A.3: Relay 300G Curves Page 250 of 263
  • Fig. A.4: Connection Diagrams Page 251 of 263
  • Protection Relay Settings for Generators Page 252 of 263
  • VII. Protection Relay Settings for the Generators The generator relay coordination and setting were selected following the IEEE Tutorial on the Protection of Synchronous Generators. The selected relay settings are for the generator capacity available for the loads. For the maximum three phase fault cases the coordination relay setting selected is approximated 24 cycles as a backup protection. Also there is an instantaneous overcurrent protection adjusted to the maximum short circuit available at the generators bus. For a ground fault the coordination relays has the approximated 24 cycles between as a backup protection. The instantaneous over current protection adjusted to the maximum short circuit at the generator bus. Protective Relay settings for generators 1. Generator 1 2. Generator 2 Page 253 of 263
  • IEEE Tutorial on the Protection of Synchronous Generators Abstracting is permitted with credit to the source. For copying, reprint, or republication permission, write to the IEEE Copyright Manager, IEEE Operation Center, 445 Hoes Lane, Piscataway, NJ 08855-1331. All rights reserved. Copyright 1995 by The Institute of Electrical and Electronics Engineers, Inc. First Printing July 1995 Second Printing October 1995 Third Printing July 1997 Fourth Printing August 1999 IEEE Catalog Number: 95TP102 Additional copies of this publication are available from IEE Operations Center P. O. Box 1331 455 Hoes Lane Piscataway, NJ 08855-1331 USA 1-800-701-IEEE 1-732-981-0060 1-732-981-9667 (FAX) Email: customer.service@ieee.org Page 254 of 263
  • A.3 General Information Page 255 of 263
  • Fault Fiter Electronic Power Fuses: Fault Fiter® Electronic Power Fuses are a major advancement in circuit-interruption technology. They integrate state-of-the-art electronics with an advanced-design high-continuous-current fuse. The electronics provide current sensing, time-current characteristics, and control power. No remote relaying or external power is required. Fault Fiter provides unsurpassed high- speed interruption of fault currents to 40,000 amperes RMS symmetrical. Fault Fiters are maintenance-free, maintenance-proof. Fault Fiter Electronic Power Fuses offer superior coordination with source-side overcurrent relays and load-side feeder fuses. They offer unmatched high-speed circuit- interrupting performance without producing excessive voltage surges, and they respond more quickly to high-current faults than conventional fuses. They're ideal for: • Service-entrance protection and coordination, • Transformer protection • Overdutied device protection. Fuse Protection Fig. A.7: Fault Fiter Fuse Page 256 of 263
  • SMU-40 300E, 30E and SMD-2C 100E Fuses Specifications: In accordance with procedures described in ANSI Standard C37.41-1981, minimum melting time-current characteristic curves for S&C power fuses are based on tests starting at no initial load. When in service, of course, every fuse will be carrying a load that may approach or even exceed the ampere rating. This preloading reduces the heat-dissipating ability of the fusible element, and hence reduces its melting time. This effect has been minimized in S&C power fuses by designing their fusible elements to melt at current levels not less than 200% of rating. Fig. A.8: Fuse Units Page 257 of 263
  • Fault Interruption — SM-20, SML-20, and SMU-40 Power Fuses Fast, positive fault interruption is achieved in the SMU Fuse Unit through high-speed elongation of the arc in the solid-material-lined bore, and by the efficient deionizing action of gases generated through thermal reaction of the solid material due to the heat of the confined arc. Here's how it works: • Overcurrent melts the silver fusible element. The strain wire severs, initiating arcing. • Released force of drive spring accelerates arcing rod upward, causing rapid elongation of the arc in the solids-material-lined bore. Under maximum fault conditions, heat from confined arc causes solid material in the large-diameter lower section of the arc-extinguishing chamber to undergo thermal reaction, generating turbulent gases and effectively enlarging the bore diameter so that the arc energy is released with a mild exhaust. Under low-to-moderate fault conditions, arc is extinguished in small-diameter up-per section of the arc-extinguishing chamber, where deionizing gases are effectively concentrated for efficient arc extinction. • Continued upper travel of the arcing rod after arc extinction causes actuating pin to penetrate the upper seal, resulting in projection of the brilliant-red blown-fuse target from the upper end fitting. Fig. A.9: SMU-40 Fuse Page 258 of 263
  • SMD-2C Fig. A.10: SMD-2C Fuse Units Fig. A.11: SMD-2C Fuse Page 259 of 263
  • Protection for Small- and Medium-Sized Generator Machines Applications: Fig. A.12: SEL 300G • Connect the SEL-300G Relay across large generators for complete primary and backup protection. Adding the neutral voltage connection provides 100 percent stator ground protection for most machines, based on third-harmonic voltage measurements. Connecting the neutral current input provides protection for solidly grounded or resistance grounded machines. • Apply sensitive percentage-restrained current differential elements and an unrestrained element, along with synchronism check and volts-per-hertz elements, across the entire unit to protect both the generator and the step-up transformer. • Replace auxiliary meters at the generating station by taking advantage of accurate internal metering. • Monitor and record generator utilization with internal hour meters that record stopped time, and full load hours. Connecting Diagram Fig. A.13: SEL 300G Installation Page 260 of 263
  • SEL-351A Fig. A.14: SEL 351A The SEL-351A includes a robust set of phase, negative sequence, residual, and neutral overcurrent elements. Each element type has six levels of instantaneous protection (four of these levels have definite-time functions). The relay provides directional control for each of these overcurrent elements. Overcurrent Elements for Phase Fault Detection Phase and negative-sequence overcurrent elements detect phase faults. Negative sequence current elements ignore three-phase load to provide more sensitive coverage of phase-to- phase faults. Phase overcurrent elements detect three-phase faults that do not have significant negativesequence quantities. Directional Protection for Various System Grounding Practices Current channel IN, ordered with the optional 0.2 A secondary nominal rating, provides directional ground protection for the following systems: • Ungrounded systems • High-impedance grounded systems • Petersen Coil grounded systems • Low-impedance grounded systems Under- and Overfrequency Protection Six levels of secure under- (81U) or overfrequency (81O) elements detect true frequency disturbances. Use the independently time-delayed output of these elements to shed load or trip local generation. Phase undervoltage supervision prevents undesired frequency element operation during faults. Page 261 of 263
  • Functional Overview Fig. A.15: SEL 351A Overview Page 262 of 263
  • ABB vacuum circuit breakers Ratings ADVAC is available in the full range of ANSI ratings through 15 kV, with interrupting ratings to 1000 MVA and continuous currents through 3000 A (self-cooled). The ADVAC series of vacuum circuit breakers is a complete line of ANSI- rated circuit breakers offering power distribution system customers the advantages of the latest vacuum circuit breaker technology. Operating Mechanism ADVAC uses a simple, front-accessible stored-energy operating mechanism designed specifically for use with vacuum technology. This provides the benefits of dependable vacuum interrupters with advanced contact design and proven reliability, without the complexity of mechanisms and linkages found in previous generation circuit breakers. Ratings The switchgear shall be rated at (4.76, 8.25, 15) kV maximum continuous voltage, (250, 350, 500, 750, 1000) MVA nominal interrupting capacity, and (1200, 2000, 3000) amps continuous current, as shown in the “Rating Structure” table (page 40), with required and related capabilities in accordance with referenced ANSI standards. Fig. A.16: ABB Vacuum Circuit Breaker Page 263 of 263