Arc Flash is much different from the conventional shock hazard in the sense that it doesn’t involve direct contact of human beings with the live or energized part. The arcing energy involves high temperature of up to or beyond 20000K. This paper presents a case study of arc flash hazard analysis carried out in older industrial plant and the technological and work procedure changes that can be incorporated to reduce the incident energy level and thus provide a safer environment for the working personnels in plant.
Practical Medium and High Voltage Testing of Electrical Equipment for Enginee...Living Online
Testing is an essential activity in any engineer's career. Whatever your role in industry (electrical designer, purchase engineer, manufacturer, installation contractor or maintenance engineer) a solid knowledge of tests to be carried out on a given piece of electrical equipment and interpretation of results obtained is a necessity.
This manual is designed to familiarise you with various aspects of testing general electrical equipment and high voltage testing in particular. Examples are cited from various international standards regarding the procedure for conducting of tests and interpreting the test results. The need for keeping proper records of tests conducted both in the initial stages and later during routine maintenance is discussed. Some of the tests are too complex to be performed on a routine basis or may require specialised equipment which may not be normally available to user industries or even manufacturers. This is where the services of an independent and accredited test lab is useful. The role of such labs is briefly discussed.
MORE INFORMATION: http://www.idc-online.com/content/practical-medium-high-voltage-testing-electrical-equipment-engineers-and-technicians-47?id=138
The webinar focused on the guideline differences associated with low voltage systems. Al Archambault, Director of Sales, used the installation of low voltage Adjustable Speed Drives (ASDs) to demonstrate to owners, operators and consulting engineers how the differences between the 1992 guideline vs the 2014 version can affect their designs when specifying and installing low voltage ASDs.
FUNDAMENTALS OF POWER SYSTEM PROTECTION
FUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTION
This Presentation is about l.v switch gear design, presented during the graduation project final discussion 15/7/2018.
It presented a good summary of switch gear components and types and practicing on AL.HAMOOL W.T.P M.D.B design using SIEMENS SIVACON S8
Schneider Electric Services_Modernization and Upgrade Solutions.pptxSchneider Electric
When considering whether to replace or upgrade existing switch gear, there are a number of factors to consider.
• Operating environment • Availability of spare parts • Impact of downtime • Cost of ongoing maintenance • Need to increase fault or continuous current rating • Desire to upgrade to current technology
Practical Medium and High Voltage Testing of Electrical Equipment for Enginee...Living Online
Testing is an essential activity in any engineer's career. Whatever your role in industry (electrical designer, purchase engineer, manufacturer, installation contractor or maintenance engineer) a solid knowledge of tests to be carried out on a given piece of electrical equipment and interpretation of results obtained is a necessity.
This manual is designed to familiarise you with various aspects of testing general electrical equipment and high voltage testing in particular. Examples are cited from various international standards regarding the procedure for conducting of tests and interpreting the test results. The need for keeping proper records of tests conducted both in the initial stages and later during routine maintenance is discussed. Some of the tests are too complex to be performed on a routine basis or may require specialised equipment which may not be normally available to user industries or even manufacturers. This is where the services of an independent and accredited test lab is useful. The role of such labs is briefly discussed.
MORE INFORMATION: http://www.idc-online.com/content/practical-medium-high-voltage-testing-electrical-equipment-engineers-and-technicians-47?id=138
The webinar focused on the guideline differences associated with low voltage systems. Al Archambault, Director of Sales, used the installation of low voltage Adjustable Speed Drives (ASDs) to demonstrate to owners, operators and consulting engineers how the differences between the 1992 guideline vs the 2014 version can affect their designs when specifying and installing low voltage ASDs.
FUNDAMENTALS OF POWER SYSTEM PROTECTION
FUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTIONFUNDAMENTALS OF POWER SYSTEM PROTECTION
This Presentation is about l.v switch gear design, presented during the graduation project final discussion 15/7/2018.
It presented a good summary of switch gear components and types and practicing on AL.HAMOOL W.T.P M.D.B design using SIEMENS SIVACON S8
Schneider Electric Services_Modernization and Upgrade Solutions.pptxSchneider Electric
When considering whether to replace or upgrade existing switch gear, there are a number of factors to consider.
• Operating environment • Availability of spare parts • Impact of downtime • Cost of ongoing maintenance • Need to increase fault or continuous current rating • Desire to upgrade to current technology
Lessons Learned of AC Arc Flash Studies for Station Auxiliary Service SystemsPower System Operation
Substation auxiliary service systems are important to supply continuous and momentary power to electrical equipment inside a substation, such as lighting, HVAC, transformer fans, circuit breaker motors, etc. [1]. As a result, station service equipment must be frequently operated or maintained. Either operation or maintenance could trigger an arc flash incident if a fault occurs simultaneously. In order to minimize potential arc flash hazards, AEP Transmission uses ASPEN to model station service systems and calculate incident energy at identified risk locations using an embedded arc flash hazard calculator based on IEEE-1584 [2]. This paper discusses various lessons learned from AEP studies with a focus on project processes and a sensitivity analysis of input data. Knowledge from these lessons learned allows arc flash studies to be more accurate, efficient, and less burdensome to station projects.
An adaptive protection scheme to prevent recloser-fuse miscoordination in dis...iosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Redundant power supply architecture for self healing substation using ultraca...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Photo Voltaic Cell Integrated DVR for Power Quality ImprovementIJMTST Journal
Grid integration of distributed energy resources (DERs) is increasing rapidly. Integration of various types of energy storage technologies like batteries, ultra capacitors (UCAPs), superconducting magnets and flywheels to support intermittent DERs, such as solar and wind, in order to improve their reliability is becoming necessary. Of all the energy storage technologies UCAPs have low energy density, high power density and fast charge/discharge characteristics. They also have more charge/discharge cycles and higher terminal voltage per module when compared to batteries. All these characteristics make UCAPs ideal choice for providing support to events on the distribution grid which require high power for short spans of time. UCAPs have traditionally been limited to regenerative braking and wind power smoothing applications. The major contribution of this dissertation is in integrating UCAPs for a broader range of applications like active/reactive power support, renewable intermittency smoothing, voltage sag/swell compensation and power quality conditioning to the distribution grid. Renewable intermittency smoothing is an application which requires bi-directional transfer of power from the grid to the UCAPs and vice-versa by charging and discharging the UCAPs. This application requires high active power support in the 10s-3min time scale which can be achieved by integrating UCAPs through a shunt active power filter (APF) which can also be used to provide active/reactive power support. Temporary voltage sag/swell compensation is another application which requires high active power support in the 3s-1min time scale which can be provided integrating UCAPs into the grid through series dynamic voltage restorer (DVR). All the above functionalities can also be provided by integrating the UCAPs into a power conditioner topology.
Effects of the Droop Speed Governor and Automatic Generation Control AGC on G...IJAPEJOURNAL
In power system, as any inequality between production and consumption results in an instantaneous change in frequency from nominal, frequency should be always monitored and controlled. Traditionally, frequency regulation is provided by varying the power output of generators which have restricted ramp rates. The Automatic Generation Control AGC process performs the task of adjusting system generation to meet the load demand and of regulating the large system frequency changes. A result of the mismatches between system load and system generation, system frequency and the desired value of 50 Hz is the accumulation of time error. How equilibrium system frequency is calculated if load parameters are frequency dependent, and how can frequency be controlled. Also, how do parameters of a speed governor affect generated power. The transient processes before system frequency settles down to steady state. Finally, AGC in what way is it different from governor action. This paper presents new approaches for AGC of power system including two areas having one steam turbines and one hydro turbine tied together through power lines.
Underwater Target Tracking Using Unscented Kalman FilterIJAPEJOURNAL
Unlike conventional active sonar, that transmits the sound signals and revealing their presence and position to enemy forces. The probable advantage of passive sonar is that it detects the signals emitted by the target, leads to improve localization, target tracking, and categorization. The challenging aspect is to estimate the true bearing and frequency measurements from the noisy measurements of the target. Here in this paper, it is recommended for the Unscented Kalman Filter (UKF) to track the target by using these noisy measurements. The Target Motion Analysis (TMA), which is the way to find the target’s trajectory by using frequency and bearing measurements, is explored. This method provides a tactical advantage over the classical bearing only tracking target motion analysis. It makes the observer maneuver unnecessary.
Investigation of Dependent Rikitake System to Initiation PointIJAPEJOURNAL
In this paper we investigate depending of the Rikitake system to initiation point, and monitor changing behavior of this system. We will have 4 initiation points in Cartesian system. We at 4 positions, will monitor behavior of this system, while holding constant other values, and after per position, will draw operation of system on axes of x, y, z and 3-D plot. We want to know, what is the effect of initiation point on Rikitake system? Numerical simulations to illustrate the effect of initiation point are presented, and at the end conclusions and comparing the states together are obtained.
Optimization of Economic Load Dispatch with Unit Commitment on Multi MachineIJAPEJOURNAL
Economic load dispatch (ELD) and Unit Commitment (UC) are significant research applications in power systems that optimize the total production cost of the predicted load demand. The UC problem determines a turn-on and turn-off schedule for a given combination of generating units, thus satisfying a set of dynamic operational constraints. ELD optimizes the operation cost for all scheduled generating units with respect to the load demands of customers. The first phase in this project is to economically schedule the distribution of generating units using Gauss seidal and the second phase is to determine optimal load distribution for the scheduled units using dynamic programming method is applied to select and choose the combination of generating units that commit and de-commit during each hour. These precommitted schedules are optimized by dynamic programming method thus producing a global optimum solution with feasible and effective solution quality, minimal cost and time and higher precision. The effectiveness of the proposed techniques is investigated on two test systems consisting of five generating units and the experiments are carried out using MATLAB R2010b software. Experimental results prove that the proposed method is capable of yielding higher quality solution including mathematical simplicity, fast convergence, diversity maintenance, robustness and scalability for the complex ELD-UC problem.
Impact of Buried Conductor Length on Computation of Earth Grid ResistanceIJAPEJOURNAL
Effective design of substation earth grid implies achieving low earth grid resistance and fulfillment of the safety criteria at the lowest possible cost. This paper presents an evaluation of IEEE Standard 80-2000 Equations 50 to 52 to determine the impact of buried conductor length on computation of earth grid resistance. Calculated results indicated that a saturation point is reached beyond which further addition of more conductor length does not significantly reduce the earth grid resistance but incurs more economic implications. These were validated by earth grids designed using CDEGS where good agreement between the calculated and simulated results was found.
Enhancing Photoelectric Conversion Efficiency of Solar Panel by Water CoolingIJAPEJOURNAL
Photovoltaic solar cell generates electricity by receiving solar irradiance. The electrical efficiency of photovoltaic (PV) cell is adversely affected by the significant increase of cell operating temperature during absorption of solar radiation. This undesirable effect can be partially avoided by cooling the back side of the photovoltaic panel using water absorption sponge which was fixed on of PV panel and maintain wet condition by circulation of drop by drop water. The objective of the present work is to reduce the temperature of the solar cell in order to increase its electrical efficiency. Experiments were performed with and without water cooling. A linear trend between the efficiency and temperature was found. Without cooling, the temperature of the panel was high and solar cells were achieved an efficiency of 8–9%. However, when the panel was operated under water cooling condition, the temperature dropped maximally by 40C leading to an increase in efficiency of solar cells by 12%.
PMU-Based Transmission Line Parameter Identification at China Southern Power ...IJAPEJOURNAL
China Southern Power Grid Company (CSG) recently developed and implemented an online PMU-based transmission line (TL) parameter identification system (TPIS). Traditionally, TL parameters are calculated based on transmission tower geometries, conductor dimension, estimates of line length, conductor sags, etc. These parameters only approximate the effect of conductor sag and ignore the dependence of impedance parameters on temperature variation. Recent development in PMU technology has made it possible to calculate TL parameters accurately. The challenges are that such application requires highly accurate PMU data while the accuracy of PMU measurements under different working/system conditions can be uncertain. With a large number of PMUs widely installed in its system, CSG plans to improve and update the EMS database using the newly developed TPIS. TPIS provides an innovative yet practical problem formulation and solution for TL parameter identification. In addition, it proposes a new metric that can be used to determine the credibility of the calculated parameters, which is missing in the literature. This paper discusses the methodologies, challenges, as well as implementation issues noticed during the development of TPIS.
Investigation of Electric Field Distribution Inside 500/220 kV Transformation...IJAPEJOURNAL
This study depicts the electric field distributions inside a typical 500/220 kV open distribution substation under actual loading conditions and during different working conditions, Hot-Stick position and Bar-Hand position. The electric field is investigated for different workers heights of 1m, 1.5m and 1.8m above ground during normal working condition (Hot-Stick position) inside this substation. This in addition to assessment of the electric field at a height levels of 8m, 11m, 14m and 17m above ground as positions for live line maintenance under 220 kV Busbars, 500 kV Busbars, 220 kV Incoming and Outgoing feeders and 500 kV Incoming and Outgoing feeders respectively. In this study the simulation results of the electric field obtained using three dimensional (3D) computer model for existing typical high voltage transformation substation are compared with field values measured inside this typical substation and presented and discussed not only in the form of contour maps but also in the form 3D surface and wireframe maps. The simulation results are good matched and agreed with measured values. This in addition to the electric field will be tabulated and compared to international guidelines for personnel exposure to electric field. This study will serve for planning service works or for inspection of equipment inside high voltage (HV) power transformation substations.
Economic Load Dispatch for Multi-Generator Systems with Units Having Nonlinea...IJAPEJOURNAL
Economic Load Dispatch aims at distributing the load demand between various generation stations in a system such that the total cost of generation is minimum. This is of vital importance since it not only reduces the operation cost of the generation utility but also helps in conserving fast dwindling energy resources. Modern day power systems are large interconnected systems with a large number of generator units each having its own cost curve. Ideally the cost function of a unit is a quadratic function of the power generated by the unit and the cost curve obtained is a smooth parabola. But in practice cost curves deviate from the idealised one due the several reasons such as valve point effect, multi fuel operation, existence of forbidden zones etc. and as such may not be continuous or analytic. Also for a large interconnected system it becomes essential to consider the effect of transmission losses. Conventional numerical method based approaches work well with systems without losses but for large systems with losses obtaining convergence becomes difficult as the number of iterations required as well as the computational time are very high. These methods fail entirely if non ideal cost curves are considered. Hence soft computing based methods become essential. Here Gravity Search Algorithm(GSA) has been used to for finding economic load scheduling in a multi generator system, given a certain load demand, and taking into consideration the effects of practical constraints on the idealised load curve. The algorithms for finding the economic scheduling has been written in Matlab and has provided satisfactory results based on the given tolerance values. Also the traditional and soft computing based approaches have been compared to demonstrate the advantages of one over the other.
Improving Light-Load Efficiency by Eliminating Interaction Effect in the Grid...IJAPEJOURNAL
A wind turbine equipped with doubly-fed induction generator (DFIG) is used in wind power plant industry. This paper studies the maximum power extraction of DFIG via evaluation of state-space equations in closed loop control condition for improving light-load efficiency. The DFIG state-space equations have been considered in the form of a multi-input- multi output (MIMO) system. Also, the tracing table has been used to determine the speed which the generated power will be proportional to the maximum load. The tracing table input is the generator speed, and its output is the optimum active power that has been considered as the reference power of the active power control system of the convertor. A controller is presented for the tracing table and the extracted power is able to follow the reference power with minimum ripple. Then, the results are compared with the single-input and single-output (SISO) case, for the values up to 0.2 times of the rated load. Therefore, in MIMO modeling, in the case that the DFIG connected to the grid, by eliminating the interaction effect, the efficiency in light-load can be increased
An Application of Ulam-Hyers Stability in DC MotorsIJAPEJOURNAL
In this paper, a generalization to nonlinear systems is proposed and applied to the motor dynamic, rotor model and stator model in DC motor equation. We argue that Ulam-Hyers stability concept is quite significant in design problems and in design analysis for the class of DC motor’s parameters. We prove the stability of nonlinear partial differential equation by using Banach’s contraction principle. As an application, the Ulam-Hyers stability of DC motor dynamics equations is investigated. To the best of our knowledge this is the first time Ulam-Hyers stability is considered from the applications point of view.
Implementation of Hybrid Generation Power System in PakistanIJAPEJOURNAL
A solar-wind hybrid power generation system has been presented here. The application based system illustrated in this paper is designed on the basis of the solar and wind data for Pakistan. The power generated by the system is intended for domestic use. The most common source of unconventional power in homes is battery based UPS (Uninterrupted power supply) inverter. The UPS inverter charges the battery with conventional grid power. This system will charge the battery of UPS inverter by using only wind and solar power, which will make the system cost effective and more reliable. The reason for using both solar and wind is that recent studies have proven that combined system can be more productive and consistent and other thing is that neither of them can be used for continuous power generation. In the system illustrated in this paper the solar-wind system provides power periodically which is controlled by electronic methods and a microcontroller is used to monitor the power from both the inputs. The switching action is provided from the microcontroller to the battery charging based on the power received from solar photovoltaic panel and wind generators. In this paper, an efficient system has been presented comprising of solar panel, wind generator, charge controller and charge storage unit (battery). Solar panel is selected as the main input and the wind resource will be used only in the absence of the solar photovoltaic (PV) output.
Modeling and Simulation of SVPWM Based ApplicationIJAPEJOURNAL
Recent developments in power electronics and semiconductor technology have lead to widespread use of power electronic converters in the power electronic systems. A number of Pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply from a three-phase voltage source inverter. Among the different PWM techniques proposed for voltage fed inverters, the sinusoidal PWM technique has been popularly accepted. But there is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization, reduced harmonics, reduced switching losses and better dc bus utilization. This project focuses on step by step development of SVPWM technique. Simulation results are obtained using MATLAB/Simulink software for effectiveness of the study.
Comparison of FACTS Devices for Two Area Power System Stability Enhancement u...IJAPEJOURNAL
Modern Power Transmission networks are becoming increasingly stressed due to growing demand and restrictions on building new lines. Losing stability is one of the major threat of such a stressed system following a disturbance. Flexible ac transmission system (FACTS) devices are found to be very effective in a transmission network for better utilization of its existing facilities without sacrificing the desired stability margin. The static synchronous compensator (STATCOM) and Static Var Compensator (SVC) are the shunt devices of the flexible AC transmission systems (FACTS) family. When system voltage is low, STATCOM generates reactive power and when system voltage is high it absorbs reactive power whereas the Static Var compensator provides the fast acting dynamic compensation in case of severe faults. In this Paper, the performance of SVC is compared with the performance of STATCOM. Proposed controllers are implemented using MATLAB/SIMULINK. Simulation results indicate that the STATCOM controller installed with two machine systems provides better damping characteristics in rotor angle as compared to two machine system installed with SVC. Thus, transient stability enhancement of the two machine system installed with STATCOM is better than that installed with SVC.
Influence of Static VAR Compensator for Undervoltage Load Shedding to Avoid V...IJAPEJOURNAL
In the recent years, operation of power systems at lower stability margins has increased the importance of system protection methods that protect the system stability against various disturbances. Among these methods, the load shedding serves as an effective and last-resort tool to prevent system frequency/voltage instability. The analysis of recent blackouts suggests that voltage collapse and voltage-related problems are also important concerns in maintaining system stability. For this reason, voltage also needs to be taken into account in load shedding schemes. This paper considers both parameters in designing a load shedding scheme to determine the amount of load to be shed and its appropriate location .The amount of load to be shed from each bus is decided using the fixed step size method and it’s location has been identified by using voltage collapse proximity index method. SVC is shunt connected FACTS device used to improve the voltage profile of the system. In this paper impact of SVC on load shedding for IEEE 14 bus system has been presented and analyzed.
Assessment of Electric Field Distribution Inside 500/220 kV Open Distribution...IJAPEJOURNAL
The high level electric field intensity produced by high voltage (HV) equipments inside 500/220 kV substations is harmful for the human (staff) health. Therefore the minimum health and safety requirements regarding the exposure of workers to the risk arising from electric fields produced inside these substations is still considered as a competitive topic for utility designers, world health organization (WHO) and biomedical field researchers. It is very important to have knowledge about levels distribution of electric field intensity within these high voltage substations as early stage in the process of substation design. This paper presents results of investigation 50Hz electric field intensity distribution inside 500/220 kV power transmission substations in Cairo, Egypt. This paper presents a method for assessment the distribution of 50HZ electric field intensity distribution inside this substation, this method of analysis is based on the charge simulation technique (CSM). This study will serve for planning service works or for inspection of equipment on HV power transmission substations.
Towards An Accurate Modeling of Frequency-dependent Wind Farm Components Unde...IJAPEJOURNAL
Frequency dependence complete model is set up for describing the lightning transient behavior of the wind turbines (WTs).To get an appropriate wind turbine model, a high frequency models of surge arrester protecting the boost transformer, transformer and ground electrode soil ionization are implemented. The transient responses and Ground Potential Rise (GPR) can be obtained at different locations in the WTs and connected grid in the time domain as well as in the frequency domain using Fast Fourier Transform (FFT). To check the validity of the model, Surge arresters protection level at different locations, at i.e. LV, MV and HV, is compared with ABB manufacture data sheet, Also a comparison has been made between simple and frequency dependence model of overall wind farm components using ATP/EMTP. This paper provides an accurate simulation of wind farm components under transient condition.
Hybrid Generation Power System for Domestic ApplicationsIJAPEJOURNAL
This work presents the plan and model of the control strategy for the interconnection of the hybrid energy system able to regulating this load’s voltage and controlling the energy generation with the energy options. The control strategy contains controlling the energy generated through each energy source, in a hierarchical mode using sliding/dropping mode control, while consuming consideration elements that have an impact on each electrical power source and transform the energy generated in order to suitable circumstances for lower power and domestic programs. The cross alternative energy system consists of photovoltaic cellular material, fuel cellular material and battery packs. A numerical equation in order to estimate the perfect voltage involving photovoltaic systems for virtually every solar irradiance and temperature circumstances is suggested. Simulations of a single or a lot more systems interconnected towards the load with the entire proposed control scheme, under different ecological and weight conditions, usually are introduced to indicate this efficiency with the procedure.
Ash Cooler Heat Recovery Under Energy Conservation SchemeIJAPEJOURNAL
A healthy fluidization state in circulating fluidized-bed combustion (CFBC) combustor is attributed to proper quantity of hot bed material (ash), which acts as a thermal fly-wheel. It receives & stores thermal energy from the burning of fuel (lignite) & distributes uniformly throughout the combustor & helps in maintaining a sustained combustion. The quantity of bed ash inside the combustor or size of the bed, depends upon boiler load & subsequently upon combustor temperature, lignite feed rate and ash % in lignite. As these parameters varies during process continuously, sometimes it becomes necessary to drain out the ash from the combustor. As & when differential pressure across the bed is increased from a justified level, draining of hot bed ash starts into Ash Coolers. Bed ash is drained at very high temperature of 850 oC & it also contains burning particles of lignite. This paper describes the heat recovery from bed ash, unloaded from the combustor into ash cooler, by pre-heating the condensate water of turbine cycle in a 125 MW CFB boiler of Surat Lignite Power Plant in India. The thermal performance of ash cooler was derived by doing a heat balance calculation based on the measured temperature of ash and cooling water with different load. From the heat balance calculation influence of ash temperature and ash amount on heat transfer coefficient is determined. Simulation is carried out around main turbine cycle indicates improved thermal economy of the unit, higher plant thermal efficiency, lower plant heat rate and reduce fuel consumption rate. Also simulation result shows that the heat transfer coefficient increase with ash amount and decreases with increase in ash temperature.
Harmonic Voltage Distortions in Power Systems Due to Non Linear LoadsIJAPEJOURNAL
Harmonics are found to have deleterious effects on power system equipments including transformers, capacitor banks, rotating machines, switchgears and protective relays. Transformers, motors and switchgears may experience increased losses and excessive heating. Shunt filters are effective in minimizing voltage distortions. This paper describes the voltage distortions generated by non linear loads. The harmonic specifications such as harmonic factor, characteristic harmonic and non-characteristic harmonic are considered while explaining the paper. ‘MiPower’ software is used to compute the harmonic distortions in a sample power system. Accurate harmonic models are established for a non linear load. To reduce the harmonic voltages impressed upon specific parts of the sample power system, passive filters are installed at two buses. With the implementation of a passive filter at the bus with non linear load, the harmonics are greatly reduced. For the specified power system, at all the buses the total harmonic distortion has been evaluated.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
The Internet of Things (IoT) is a revolutionary concept that connects everyday objects and devices to the internet, enabling them to communicate, collect, and exchange data. Imagine a world where your refrigerator notifies you when you’re running low on groceries, or streetlights adjust their brightness based on traffic patterns – that’s the power of IoT. In essence, IoT transforms ordinary objects into smart, interconnected devices, creating a network of endless possibilities.
Here is a blog on the role of electrical and electronics engineers in IOT. Let's dig in!!!!
For more such content visit: https://nttftrg.com/
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
2. ISSN: 2252-8792
IJAPE Vol. 3, No. 1, April 2014 : 23 – 32
24
voltage and source feed, if not already done. A spreadsheet should be made and following data should be
captured in that.
a. Generator
i. Rating (MVA)
ii. Sub-transient reactance
iii. Bus to which connected
b. Transformer
i. Rating (MVA)
ii. Voltage Ratio
iii. Percentage impedance
iv. Bus to and from
c. Transmission Line
i. Length (km)
ii. Type of Conductor
iii. Impedance (Ω/km)
iv. Number of lines in parallel
d. Motor
i. Rating (kW)
ii. Type of motor
iii. Ratio of starting current to rated current
e. Cable
i. Size of cable
ii. Material
iii. Make
iv. Rating (A)
v. Length of cable
vi. Number of runs
vii. Bus to and from
f. Relay
i. Type (Electromechanical/Solid state/Numerical)
ii. Setting range
iii. Setting (PSM, TMS/Set current, time)
g. CT
i. Ratio
ii. Secondary rating
h. Breaker
i. Breaking capacity
ii. Trip units, if any
i. Bus
i. Names
ii. kV Level
iii. Design Fault withstand levels
iv. Conductor gaps
v. Switchgear type (Box or Open)
The data captured above can be used to prepare an updated single line diagram incorporating the
ratings of equipment and the relay settings. Also, various configurations of operation of Power system should
be mentioned on the SLD (Single Line Diagram) indicating the status of breakers, transformers etc. during
these configurations. Separate SLDs can be made for this purpose.
There should be a listing of jobs being carried out in plant at various times including any switching
operations, maintenance jobs, testing etc.
The listing should also include the nature of job i.e. whether it is to be done online/offline. Most of
the jobs to be carried out in a substation can be done in de-energized state thus making the job safe for the
workers. For further insurance of safety for such kind of jobs, prior to carrying out the job, the de-energized
state should be confirmed by a tested voltage detector. This will avoid human errors like working on the
neighboring compartment, any breaker accidentally remaining closed etc. Also the voltage detector should be
tested near any live equipment every time it is being used to ensure it does not give erroneous indication.
Proper grounding should be provided not by insulation stick but by fixed clips to ensure the system is
grounded while carrying out the job. The removal of grounding should be ensured before restoration of
supply (to be incorporated in check sheet).
3. IJAPE ISSN: 2252-8792
Remediation of Old Substations for Arc Flash Hazard (Zakir Husain)
25
Thus, Jobs to be done in live state are very limited. Out of these, the remote operation and remote
racking of breakers can further reduce the exposure level of workers. The remote operation can be
implemented by making simple changes in the control circuit of the equipment while it is taken out for
maintenance. Remote racking, while not always physically possible in existing plants, can always be
considered a possibility and retrofitting feasibility should be checked. Such Jobs require bare minimum
change to the existing equipment and are most economical. They should be identified from the list of jobs
and changes should be planned in a phase wise manner during their scheduled outage.
Fig. 1. Remote Power Racking Unit
Only those jobs should be highlighted which cannot be done in de-energized condition. The fault
levels at these job locations should be calculated by carrying out Short circuit study. It should be ascertained
that the Buses/cables/Breakers/CT secondary are designed for withstanding these fault levels as in any old
substation many loads are added later on or the buses are extended without paying much attention to the
design withstand fault levels. Relay coordination for the existing relay settings should be confirmed before
carrying arc flash analysis. Any adjustments in relay settings, if required, should be made at this point.
The arc fault current levels should be calculated at the identified job locations as per IEEE 1584.
The time of operation as per the relay settings for the arc fault current should be determined.
The incident energy and flash protection boundary can then be calculated by the empirical equations
given by IEEE 1584 and the areas with energy levels > 1.2 cal/cm2 are to be identified.
At this point, the identified locations with incident energy levels > 1.2 cal/cm2 should be checked
for these points, if applicable, to bring down the energy levels:
1. While carrying out any switching actions there should be well documented procedures/ checksheets
marking even the switch and compartment number to avoid human mistakes.
2. During maintenance of a breaker if any check on live bus bar is to be made to check pitting, it should be
made by two-pronged shutter lifter made of insulator.
3. Only Trained Personnels should be allowed for such jobs in presence of a standby person to avoid
errors. Personnels should be given live demo on spare on decommissioned equipment.
4. Provision of viewing window with better emissivity for jobs like thermography so that the panel
compartment is not required to be opened
5. Provision of Maintenance bypass switch to incorporate an alternate set of relay settings for
instantaneous operation of relay in the event of fault while working on the system. These settings
should be normalized after the job is finished.
6. Retrofitting to arc resistant switchgears in specific problematic areas.
7. Use of Category III or IV multimeter.
8. If there is a load mixup of areas in MCCs, this should be rectified in any scheduled outage so that it
does not cause heartburn.
9. Provision of fused incoming and change fuses of normal type with current limiting type (class RK1).
10. In earlier designs the LV motors are provided with only short-circuit (cleared by fuses) and thermal
protection (cleared by contactor). While for faults involving two phases and single-phase ground, the
fuse will take a lot of time for clearing the fault. Thus the cost vs benefit for providing additional relay
protection on high rating motors for fast isolation should be carefully considered. For this, the LV
4. ISSN: 2252-8792
IJAPE Vol. 3, No. 1, April 2014 : 23 – 32
26
contactors breaking capacity in case of faults should be checked. Other Solutions - Temporary Reduced
Settings, Arc Sensing Relays, Zone Selective Interlocking, Arc Containment Device and PPEs. The
temporary reduced settings of relay requires specific capable trip systems and does not provide
protection if the event does not occur during the planned activity. The provision of light sensors along
with current input from CT and Zone selective interlocking can also be used for instantaneous tripping
purpose for the arc fault. However for higher hazard risk category jobs even the 3-cycle time to be
taken by breaker to clear the fault will not be acceptable. Thus in such cases, arc containment device
can be used. The last line of defense can be PPE to be used while working. In market as of now even
40cal/cm2 suits are available. But these suits are very bulky and may lead to difficulty in carrying out
the job. Thus, after reducing the energy levels as much as possible by other means as described above,
the PPE should be chosen. After this, as per The National Electrical Code (NEC), Section 110.16, a Arc
Flash Hazard Warning label should be placed on the equipment to warn the qualified persons of
potential electric arc hazards. It should be placed so as to be clearly visible, should include the Hazard
risk category, flash protection boundary and recommended PPEs required if work is to be done in
normal working distance. Here for study a sample single line diagram is taken where the bolted fault
levels and protective device ratings are calculated for different possible configurations for operating the
Power System. Other Solutions - Temporary Reduced Settings, Arc Sensing Relays, Zone Selective
Interlocking, Arc Containment Device and PPEs. The temporary reduced settings of relay requires
specific capable trip systems and does not provide protection if the event does not occur during the
planned activity. The provision of light sensors along with current input from CT and Zone selective
interlocking can also be used for instantaneous tripping purpose for the arc fault.
However for higher hazard risk category jobs even the 3-cycle time to be taken by breaker to clear
the fault will not be acceptable. Thus in such cases, arc containment device can be used. The last line of
defense can be PPE to be used while working. In market as of now even 40cal/cm2 suits are available. But
these suits are very bulky and may lead to difficulty in carrying out the job. Thus, after reducing the energy
levels as much as possible by other means as described above, the PPE should be chosen. After this, as per
The National Electrical Code (NEC), Section 110.16, a Arc Flash Hazard Warning label should be placed on
the equipment to warn the qualified persons of potential electric arc hazards. It should be placed so as to be
clearly visible, should include the Hazard risk category, flash protection boundary and recommended PPEs
required if work is to be done in normal working distance. Here for study a sample single line diagram is
taken where the bolted fault levels and protective device ratings are calculated for different possible
configurations for operating the Power System.
3. SAMPLE SYSTEM FAULT CALCULATION
The Single Line diagram for the sample system is as shown below:
Fig. 2. ingle Line Diagram of a Sample system
5. IJAPE ISSN: 2252-8792
Remediation of Old Substations for Arc Flash Hazard (Zakir Husain)
27
The Sample system consists of a plant having Captive Power Generation of 31.5MVA in order to
self-sustain the plant along with running it in parallel with the grid for improved reliability.
The Power from grid is being received by the plant at 33kV level and then is being step down to
11kV, 6.6kV and 415V for subsequent distribution to loads.
At each distribution level there are 2 transformers each individually capable of feeding the load. The
extra capacity is provided for future usage.
Now short circuit study is carried out on the given system to calculate bolted fault current levels.
Here, Different operating configurations and their impact on Bolted fault current and arc flash levels is
considered. The different cases considered are:
Case 1: T1, T3, T5 in line
Case 2: T1, T3, T4, T5, T6 in line
Case 3: T1, T2, T3, T5 in line
Case 4: All Transformers in line
Thus bolted fault current levels of the buses are as given in Table I. Here Bus 1 is not considered as it
is directly connected to the grid and any work on it will be done after disconnecting from the grid.
TABLE I. FAULT CURRENT WHEN SYSTEM RUNNING IN PARALLEL WITH GRID
Bus Name
Voltage
level (kV)
Bolted Fault Current (kA)
Case 1 Case 2 Case 3 Case 4
Bus 2 11 16.87 22.47
Bus 3 6.6 10.93 15.2 11.42 16.5
PCC 0.415 28.9 54.32 29.39 56.02
As can be seen the fault levels vary widely with different operating configurations and also with the
rating of different equipment like transformer, generator chosen during system design. The least fault level of
system is there when only one transformer is operated. But this will decrease the reliability of the system as
this transformer failure can lead to complete loss of power. Further even with one transformer operation the
fault current levels will change with system operation in parallel with grid or in isolated condition (as shown in
Table II).
Case 5: Isolated + T3, T5 in line
Case 6: Isolated + All Transformers in line
TABLE II. FAULT CURRENT WHEN SYSTEM RUNNING IN ISOLATED CONDITION
Bus Name Voltage level (kV)
Bolted Fault Current (kA)
Case 5 Case 6
Bus 2 11 11.25
Bus 3 6.6 6.4 9.55
PCC 0.415 28.012 51.19
Thus, a compromise has to be reached between reliability and fault level of system. The design of the
system as well as the configuration in which it is operated has a major impact on the arc flash levels. The study
should be carried out for arc flash current levels and energies keeping all the scenarios of system operation in
mind so as to ascertain the best operating scenario.
4. PROTECTIVE DEVICE COORDINATION
Relays provided at different levels, their settings and characteristics data for the SLD given is
determined based on the load data, fault levels, relay coordination [6] etc. The coordination curves are as given
below. As of now, arc flash protection is not taken into consideration and calculations are done only for bolted
fault current levels.
6. ISSN: 2252-8792
IJAPE Vol. 3, No. 1, April 2014 : 23 – 32
28
Fig. 1. Relay Coordination of 415V system before arc flash calculations are taken into consideration
Fig. 2. Relay Coordination of 6.6kV system before arc flash calculations are taken into consideration
During the relay selection and coordination when arc flash current is not taken into account, the two
most important features to be kept in mind are that the selective coordination should be strictly followed i.e.
the breaker closest to the fault should operate first and if it fails to operate, only then the upstream breaker
should operate and in the event of starting of highest rating motor while other connected loads are running,
the relay should have a time delay greater than the starting time of the machine so as to avoid erroneous
operation of the protection system when there is no fault.
7. IJAPE ISSN: 2252-8792
Remediation of Old Substations for Arc Flash Hazard (Zakir Husain)
29
5. ARC FLASH CALCULATION
Many methods for Arc fault Hazard level calculation have been given till now. Ralph Lee’s method is
one of the first methods but it gives conservative results and is only referred for voltage levels beyond 15kV
for which the tests by IEEE were not carried out. The IEEE 1584 method till now is the most accurate method
as it has been found out on the basis of regression analysis of the experimental data obtained by carrying out
the test.
As per IEEE 1584 [1], the empirical equations for arc flash levels are as given below:
a. Arc Fault Current and Clearing time
For PCC (< 1kV system),
Arc Fault Current,
Ia = 10 (K + 0.662 log (I
bf
) + 0.0966V + 0.000526G + 0.5588V log (I
bf
) – 0.00304G log (I
bf
))
Where, K = -0.153 for open configuration and -0.097 for box configuration
V = system voltage in kV,
G = conductor gap in mm
I
bf = Bolted Fault Current
I
a = Arc fault Current
For Voltages >1kV and < 15kV,
Ia = 10 (0.00402 + 0.983 log (I
bf
))
The fault clearing time for Ia and 85% of Ia can be checked from the relay operation curve.
From this calculated arc fault current and the fault clearing time, the incident energy at a distance of
610mm from the source of arc is ca lculated as given below:
b. Normalized Incident Energy and Incident energy at working distance
Normalized Energy,
En = 10 (K1 + K2 + 1.081 log Ia + 0.0011G)
Where,
K1 = -0.792 for open configuration and
-0.555 for box configuration,
K2 = 0 for ungrounded and high resistance grounding and
-0.113, grounded system
En is in J/cm2
(5 J/cm2
= 1.2 cal/cm2
)
Incident energy, E = 4.184CfEn (t/0.2) (610x
/Dx
)
Where, Cf = calculation factor
= 1, > 1kV
= 1.5, <= 1kV
x = 1.473, switchgear (<1kV)
= 0.973, switchgear (>5 – 15 kV)
D = working distance in mm
En = normalized incident energy
For V> 15kV, Ralph Lee’s method [2] is used for Incident energy calculation
E = 2.142 X 106
V Ibf (t/D2
)
The arc flash current, its clearing time, incident energy released at working distance are provided in the
Table III, IV and V for different buses at various bolted fault current levels for configurations considered
above.
8. ISSN: 2252-8792
IJAPE Vol. 3, No. 1, April 2014 : 23 – 32
30
TABLE III. INITIAL ARC FLASH LEVELS AS PER IEEE 1584 (BUS 2)
Bus No.
Voltage
(kV)
Case
Bolted Fault
Current (kA)
Arc Fault
Current (kA)
100% and
85%
Time of clearing
arc fault current
(sec)
Incident Energy
released at
working distance
(cal/cm2)
Bus 2 11
1 16.87
16.23 0.1 2.184
13.79 0.1 1.832
2 16.87
16.23 0.1 2.184
13.79 0.1 1.832
3 22.47
21.51 0.1 2.962
18.28 0.1 2.484
4 22.47
21.51 0.1 2.962
18.28 0.1 2.484
5 11.25
10.9 0.1 1.42
9.26 0.1 1.191
6 11.25
10.9 0.1 1.42
9.26 0.1 1.191
TABLE IV. INITIAL ARC FLASH LEVELS AS PER IEEE 1584 (BUS 3)
Bus No.
Voltage
(kV)
Case
Bolted Fault
Current (kA)
Arc Fault
Current (kA)
100% and
85%
Time of
clearing arc
fault current
(sec)
Incident Energy
released at working
distance (cal/cm2)
Bus 3 6.6
1 10.93
10.59 0.2232 2.72178
9 0.2382 2.4367
2 15.2
14.65 0.1982 3.4312
12.45 0.21 3.0498
3 11.42
11.06 0.2196 2.8056
9.4 0.234 2.5079
4 16.5
15.88 0.1928 3.6419
13.5 0.204 3.2326
5 6.4
6.26 0.2801 1.9341
5.32 0.3038 1.7597
6 9.55
9.28 0.2353 2.4859
7.88 0.252 2.2334
TABLE V. INITIAL ARC FLASH LEVELS AS PER IEEE 1584 (PCC)
Bus No.
Voltage
(kV)
Case
Bolted Fault
Current (kA)
Arc Fault
Current (kA)
100% and
85%
Time of
clearing arc
fault current
(sec)
Incident Energy
released at working
distance (cal/cm2)
PCC 0.415
1 28.9
14.16 0.6608 19.9886
12.04 0.7137 18.1105
2 54.32
23.73 0.5345 28.2471
20.17 0.5689 25.2211
3 29.39
14.36 0.6567 20.1637
12.2 0.7088 18.2563
4 56.02
24.33 0.5295 28.7558
20.68 0.5633 25.6626
5 28.012
13.8 0.6686 19.6742
11.73 0.7226 17.8383
6 51.19
22.604 0.5444 27.3
19.21 0.58 24.3988
From the above tables, it can be clearly seen that the most favorable scheme of operation under
normal condition is Case 1 with one transformer only in operation. When work is to be done on energized
equipment, the best mode of operation is Case 5 i.e. in isolated condition with only one transformer in
operation to feed each bus.
Any changes in the setting of the relay to bring down the clearing time so as to lower the incident
energy in older plants with limited range of settings in the existing electromechanical relays results in Relay
coordination disturbance and may lead to operation of the relay even under through fault conditions and
isolation of even normal areas.
Under these limitations two possible actions that can be taken are:
9. IJAPE ISSN: 2252-8792
Remediation of Old Substations for Arc Flash Hazard (Zakir Husain)
31
Zone Selective Interlocking
Zone Selective Interlocking (ZSI) can be incorporated in such a case so that if the breaker nearest to
the fault senses it will give locking command to the upstream breaker and will clear the fault without any
intentional time delay irrespective of the setting of the relay.
Temporary Reduced Setting
Another feasible solution for this is by providing maintenance bypass switch which will provide a
different set of relay settings during any maintenance activity thus giving instantaneous clearance of arc fault
or by providing unit differential protection on the bus, the fault current levels and thus the incident energy
can be reduced substantially. The levels thus reduced are given in Table VI.
TABLE VI. FINAL ARC FLASH LEVELS AS PER IEEE 1584 BY LOWERING CLEARING TIME
Bus
No.
Voltage
(kV)
Bolted Fault
Current (kA)
Arc Fault
Current
(kA)
Time of clearing
arc fault current
(sec)
Incident Energy
released at working
distance (cal/cm2)
Bus 2 11 16.87 16.2283 0.1 2.184
Bus 3 6.6 10.93 10.5921 0.1 1.22
PCC 0.415 28.9 14.1615 0.1 3.025
The Flash Protection Boundary is defined as an approach limit at a distance from live parts that are
uninsulated or exposed within which a person could receive a second degree burn (IEEE 1584[1]). It can be
calculates as.
c. Flash Protection Boundary
DB = [4.184Cf En (t/0.2) (610x
/EB)] 1/x
Or by Lee’s method,
DB = [2.142 X 106
V Ibf (t/EB)]1/2
Where,
EB = 5 J/cm2
for bare skin (second degree burns, curable)
= 33.33 J/cm2
for PPE of 8 cal/cm2
Thus, flash protection boundary i.e. safe working distance for bare skin and with PPE of 8 cal/cm2
[5] before and after remediation is shown in Table VII and VIII.
TABLE VII. FLASH PROTECTION BOUNDARY BEFORE REMEDIATION
Bus No. Voltage (kV)
Flash Protection Boundary (m)
IEEE 1584
1.2 cal/cm2
(bare skin) 8 cal/cm2
(PPE)
Bus 2 11 1.68 0.24
Bus 3 6.6 2.1 0.3
PCC 0.415 3.4 1.065
TABLE VIII. FLASH PROTECTION BOUNDARY AFTER REMEDIATION
Bus No. Voltage (kV)
Flash Protection Boundary (m)
IEEE 1584
1.2 cal/cm2
(bare skin) 8 cal/cm2
(PPE)
Bus 2 11 1.68 0.24
Bus 3 6.6 0.925 0.132
PCC 0.415 1.071 0.337
As can be seen from above the approach distances and incident energies reduced considerably for
the 415V PCC system and 6.6kV Bus. With PPEs of 8 cal/cm2, the work can be safely done without any
harm to the operators.
10. ISSN: 2252-8792
IJAPE Vol. 3, No. 1, April 2014 : 23 – 32
32
Arc Containment Device [6]
Another solution that can be used is the arc containment device [6] which is essentially an enclosure
containing electrodes. With the help of trigerring through light sensors and CT input the plasma gun can be
used to divert the arc from the switchgear to this device with impedance lower than the arcing impedance.
Thus arc current starts passing through this chamber and the interruption of arc takes place in 7-8ms as
compared to almost 100ms taken by the breaker. This leads to drastic reduction of the arc energy and safety
of workers. The calculations are shown in Table IX with a clearing time of 10ms.
TABLE IX. FLASH PROTECTION BOUNDARY AFTER REMEDIATION WITH THE HELP OF ARC CONTAINMENT
DEVICE
Bus No. Voltage (kV)
Flash Protection
Boundary (m)
IEEE 1584
1.2 cal/cm2
(bare
skin)
Bus 2 11 0.158
Bus 3 6.6 0.087
PCC 0.415 0.263
But prior to using the arc containment device, its effect on the BIL of the system or any other
harmful effects during normal operation of the Power system should be considered. Care should be taken so
that this unit does not operate under normal switching operations. For this test should be carried out after
commissioning and before taking into line. Also, there should be provision of checking the condition of
electrodes and replacement if required during routine maintenance or after failure.
7. CONCLUSION
Safety of working personnel is paramount while carrying out any job on electrical equipment and
any mistake could lead to damage to both personnel working in the vicinity and equipment. To avoid such
occurrences, As much as possible, the maintenance work on any electrical system should be carried out after
de-energizing the equipment to be taken for maintenance and proper work procedures and checks should be
put into practice prior to starting the job. However, if it is impossible to avoid working on live panels like in
case of Thermography etc., It has been found from the above calculations that by minor changes in the
Protection logic of the existing system the safety of the working personnel can be ensured.
REFERENCES
[1] IEEE Guide for Performing Arc Flash Hazard Calculations, IEEE Std 1584-2002.
[2] R. H. Lee. “The Other Electrical Hazard: Electric Arc Burns”, IEEE Power Systems Protection Committee Annual
Conf. and Record, Philadelphia, PA, Oct. 5-9,1981.
[3] Doughty,R.L.,Neal,T.E.,and Floyd,H.L. “Predicting incident energy to better manage the electric arc hazard on
600-V power distribution systems”, IEEE Transactions on Industry Applications, Vol/Issue: 36(1). Pp. 257-269,
2000.
[4] NFPA 70E, Electrical Safety in Workplace, 2009.
[5] J.C. Das. “Protection planning and system design to reduce arc flash incident energy in a multivoltage level
distribution system to 8 cal/cm2 (HRC2) or less-Part 1. Methodology”, In conf. record, IEEE Pulp and Paper
Industry Conference, San Antonio, 2010.
[6] Roscoe, G. Papallo T. and Marcelo Valdes P.E. Arc Flash Energy Mitigation by Fast Energy Capture.