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  2. 2. SUBSTATION AUTOMATIONPREFACEThis report prepared during training is life’s greatest learning experience, as it is full ofobservation and knowledge. This period also provide a chance to give theoretical knowledgeinto a practical shape. Most importantly we have been given the exposure to the latesttechnology in the world of SCADA. This report is a result of five weeks training that we arehaving in BSES, New Delhi. Joining BSES as a trainee gave me a solid platform in the beginningof my professional career.We whole heartedly thank the company as well as their SCADA team for giving us theopportunities to work on the latest technology and bring out the best in us and developing ourtalents, not only in the technical field but also how to work in a team. Co-operating andassisting each other in the department helped us to explore potential and perform muchbetter. 2BSES
  3. 3. SUBSTATION AUTOMATIONACKNOWLEDGEMENTA training of such a comprehensive coverage cannot be realized without help from numeroussources and people in the organization.I am thankful to Mr. S.S. Sondhi, for providing necessary facility to carry out my training successfully.I like to take this opportunity to show my gratitude towards Mr. Tanmay Malwho helped me in bringing the project to its present form. They have been a motivator& source of inspiration for me to carry out the necessary proceedings for the project to becompleted successfully.Finally I would like to take this opportunity to thank the organization, BSES who helped me toacquire proper knowledge and success in my training.I shall cherish the memories of the co-operation and help extended by the staff of thisorganization to a trainee and shall feel honored if I could be of any help to this organization. 3BSES
  4. 4. SUBSTATION AUTOMATION TABLE OF CONTENTS 1. Company Profile- Page 1 2. About the Project (SCADA)- Page 11 3. Remote Terminal Unit (RTU560A)- Page 18 4. Communication Subsystem- Page 27 5. Control Centre Subsystem- Page 38 a) Work Station or Control Room-Page 38 b) Communication Room – PCU 400- Page 46 6. SCADA advantages- Page 48 7. Bibliography- Page 49 4BSES
  5. 5. SUBSTATION AUTOMATION COMPANY PROFILEBSES Limited is India’s premier utility engaged in the generation, transmission and distributionof electricity. Formerly known as Bombay Suburban Electric Supply Limited, it wasincorporated on 1st October 1929, for the distribution of electricity in suburbs of Mumbai, witha pioneering mission to make available uninterrupted, reliable, and quality power to customerand provide value added services for the development of power and infrastructure sectors.BSES was amongst the first utilities in India to adopt computerization in1967 to meet theincreasing work load and to improve services to its customers.As a part of active support to the privatization process, BSES has acquired an equity of 51% inDelhi’s power sector and unbundling of the Delhi Vidyut Board in July 2002, the business ofpower distribution was transferred to BSES Yamuna Power Limited (BYPL) and BSES RajdhaniPower Limited (BRPL). These two of the three successor entities distribute electricity to 25 lakhcustomers spread across 950 sq-km area – 70% of Delhi’s geographical area.Delhi’s tryst with power privatization has shown brilliant results. The unparalleledachievements of the electricity distribution sector in Delhi stand out as the most “successfulexperiment and replicable model” of Public-Private-partnership (PPP). This view has beenupheld repeatedly by ICRA and CRISIL for the Ministry of Power, Govt. of India. 5BSES Page 1
  7. 7. SUBSTATION AUTOMATION ROAD MAP TO PRIVATISATIONThe power situation in Delhi till a few years ago was yet another example of man’s incapacityto handle another form of energy. The Delhi Vidyut Board (DVB) was a State Electricity Boardset up in 1997 under the Electricity (Supply) Act, 1948, succeeding the Delhi Electricity SupplyUndertaking (DESU) which has existed since 1957 as a wing of the Municipal Corporation ofDelhi. It was an integrated utility with generation, transmission and distribution functionsserving all of Delhi except the NDMC and MES (Cantonment) areas to which it supplied powerin bulk.The creation of DVB, replacing DESU, is 1997 proved to be merely a change in the legal statusof the organization and was not followed by any real change in its structure, functioning andwork culture. Its reputation continued to deteriorate and its poor commercial performance,the best known thing about DVB perhaps being its high Transmission and Distribution (T&D)losses made it a drain on the public exchequer. Further, failure in raising the resourcesnecessary for improvement of its services made matters critical. There were unprecedented,widespread expressions of public discontent during the difficult summer of 1998.In December 1998 when the present Government came to power in Delhi, the power situationwas grim to say the least. With T & D losses as high as 50% regular power cute for 10 to 15hours and Delhi Vidyut Board accumulating liabilities of over Rs. 23,000 crores, DelhiGovernment had to come up with a fast and viable alternative. An alternative that would notonly meet people’s aspirations in terms of its end result but also be interesting enough forinvestors. And thus began a step by step process of a never-before fundamental powerreform. 7BSES Page 3
  8. 8. SUBSTATION AUTOMATIONDelhi Electricity Board Regulatory Commission (DERC) was constituted in May 1999 whoseprime responsibility was to look into the entire gamut of existing activity and search forvarious ways of power sector reforms. The DERC is even today a fully functional body whichhas since issued tariff orders for annual revenue requirement. Delhi Electricity ReformOrdinance, 2000 was a body which was promulgated in October 2000 and notified in the formof an Act in March 2001. It mainly provides for the constitution of an Electricity RegulatoryCommission, unbundling of DVB into separate generation, transmission and distributioncompanies and increasing avenues for participation of private sector.This was followed with a Tripartite Agreement which was signed by the Government of Delhi,DVB employees to ensure the cooperation of stakeholders in this reform process. Thetripartite agreement sent off very positive vibes to the people in general as well as to theinvestor community about the sincere and hassle-free objectives of power reforms.Next, a two stage competitive bidding process of Request for Qualification (RFQ) and Requestfor Proposal (RFP) was set into motion for privatization of the distribution companies.The bidders were selected on the basis of reduction of total Aggregate Technical andCommercial of losses (AT & C) a unique feature of the power sector reforms in Delhi. Thebidders were required to bid on the basis of efficiency improvement like reduction of AT & Closses that they achieve year wise over a period of five years. 8BSES Page 4
  9. 9. SUBSTATION AUTOMATIONOn July 1, 2002, The Delhi Vidyut Board (DVB) was unbundled into six successorcompanies: Delhi Power Supply Company Limited (DPCL)- Holding Company; Delhi TranscoLimited (DTL) - TRANSCO; Indraprastha Power Generation Company Limited (IPGCL) -GENCO; BSES Rajdhani Power Limited (BRPL) - DISCOM; BSES Yamuna Power Limited (BYPL) -DISCOM; North Delhi Power Limited (NDPL) - DISCOM.The Government handed over the management of the business of electricity distributions totheir private companies BRPL , BYPL and NDPL since July 1, 2002 with 51% equity with theprivate sector.(DVB itself was the successor entity to the Delhi Electricity Supply Undertaking(DESU).Of these five companies, BRPL, BYPL and NDPL are joint ventures between the DelhiGovernment and the private sector which handle the power distribution sector in Delhi. BRPLis responsible for distribution of power in Central, South and West Delhi. BYPL handles powerdistribution in East Delhi (Trans-Yamuna). NDPL distributes power in North and North-WestDelhi. The remaining two companies, DTL and IPGCL, are wholly owned by the DelhiGovernment. Delhi Transco Limited is a State Transmission Utility of the National Capital ofDelhi, whereas IPGCL is responsible for power generation.Over the years, DTL has evolved as a most dynamic performer, keeping pace with the many-fold challenges that confront the ever increasing demand-supply-power-situation andachieving functional superiority on all fronts. The Transmission losses have been brought downfrom 3.84% in 2002-03 to 0.83% in 2006-07, and are the lowest in the country. Delhi, being thecapital of India and the hub of commercial activities in the Northern Region, coupled with theprosperity of population, the load requirement has been growing at a much faster pace.Added to that, being the focus of socio-economic and political life of India, Delhi is assumingincreasing eminence among the great cities of the world. Plus the vision-2021, aiming to makeDelhi a global Metropolitan and world class city demands greater infrastructure to enrichmany services of infrastructure development.DTL has been responsibly playing its role in establishing, upgrading, operating and maintainingthe EHV (Extra High Voltage) network. DTL has also been assigned the responsibility of runningthe State Load Dispatch Centre which is an apex body to ensure integrated operations ofpower systems in Delhi. 9BSES Page 5
  10. 10. SUBSTATION AUTOMATION BSES (RAJDHANI & YAMUNA)BSES (Brihan- Mumbai sub-urban electricity supply) is an electricity distribution companysupported by Reliance Energy.BSES is responsible for electricity distribution only. It can contribute no more than it receivespower from the generating stations in Delhi and the Northern grid. To provide reliable andquality power supply to its consumers, the company has been divided into two branches thatare BSES-YAMUNA and BSES-RAJDHANI.BSES-RAJDHANI looks over the electricity distribution to West and South Delhi. Whereas BSES-YAMUNA is responsible for electricity distribution to Central and East Delhi . 10BSES Page 6
  11. 11. SUBSTATION AUTOMATION BSES Yamuna Power LimitedCovers East & Central regions 1. Yamuna Vihar 2. Krishna Nagar 3. Chandni Chowk 4. Paharganj 5. Nand Nagri 6. Mayur Vihar 7. Daryaganj 8. Jhilmil 9. Laxminagar 10. Shankar Road 11BSES Page 7
  12. 12. SUBSTATION AUTOMATION BSES Rajdhani Power LimitedCovers South and West regions 1. Nehru Place 2. R K Puram 3. Vikaspuri 4. Najafgarh 5. Alaknanda 6. Mehrauli 7. Palam 8. Nangloi 9. Nizamuddin 10. Janakpuri 11. Punjabi Bagh 12BSES Page 8
  13. 13. SUBSTATION AUTOMATION DELHI DISTRIBUTION NETWORKThe existing RELIANCE ENERGY distribution network in DELHI is being operated at 66 KV/33KV/11 KV and 0.415 KV, with bulk supply at 66 KV/33 KV/11 KV voltage levels available fromTRANSCO.Presently Delhi network is operated sub-optimally and is predominantly manual at a local levelbased on instructions conveyed from the central location at Balaji Estate through telephone /VHF radios. The decision making at the central location is based on wall mounted static mimicdiagrams of the primary network.Delhi draws power from 400kv Northern Grid at 400/220kV stations. Delhi’s transmissionsystem at 220kV consists of twenty three 220kV interconnected sub-stations.The powers from these 220/66 kV & 220/33 kV sub-stations of Transco are fed to RELIANCEENERGY Delhi area through 20 injection points at 66kV & 33 kV voltage level, which are furtherdistributed to local transformers which step down the 66kV & 33kV to 11kV which is furtherdirectly fed to industries and the local feeders where further the 11kV is step down to 440V forhouse hold appliances. 13BSES Page 9
  15. 15. SUBSTATION AUTOMATION WHAT IS SCADA?SCADA stands for supervisory control and data acquisition. It generally refers to an industrialcontrol system: a computer system monitoring and controlling a process. The process can beindustrial, infrastructure or facility-based as described below: Industrial processes include those of manufacturing, production, power generation, fabrication, and refining, and may run in continuous, batch, repetitive, or discrete modes. Infrastructure processes may be public or private, and include water treatment and distribution, wastewater collection and treatment, oil and gas pipelines, electrical power transmission and distribution, Wind Farms, civil defense siren systems, and large communication systems. Facility processes occur both in public facilities and private ones, including buildings, airports, ships, and space stations. They monitor and control HVAC, access, and energy consumption.Common system componentsA SCADA System usually consists of the following subsystems: A Human-Machine Interface or HMI is the apparatus which presents process data to a human operator, and through this, the human operator monitors and controls the process. A supervisory (computer) system, gathering (acquiring) data on the process and sending commands (control) to the process. Remote Terminal Units (RTUs) connecting to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system. Programmable Logic Controller (PLCs) used as field devices because they are more economical, versatile, flexible, and configurable than special-purpose RTUs. Communication infrastructure connecting the supervisory system to the Remote Terminal Units. 15BSES Page 11
  16. 16. SUBSTATION AUTOMATIONNEED OF SCADA IN SUBSTATIONWhat we are doing here is Substation Automation: Following aspects can be considered whichare as follows:-Requirements for System Operations: Demand Availability Shortfall System frequency Capacity of transmission lines and transformers Loading on transmission lines and transformers Transformers installed in the system Reactive loading on the network Alternative sourcesEarlier methods used to acquire data PLCC network Wireless VHF sets P&T /FWP telephones Load pattern obtained in writing PTW Book etc...Limitations of old methods Outage of telephone / PLCC network Non-clarity of speech Human factor No control on operations 16BSES Page 12
  17. 17. SUBSTATION AUTOMATION Huge time required to collect data No check on improper compliance of instructions Huge time required to pass instructionsNeed for automation Improve information availability and better visibility Reduction of Fault Restoration times and adequate response to customer query Real time and historical data for network analysisSubstation equipments generally are categorized into two domains primaryEquipments and secondary equipments. Primary equipments include transformer,Switchgear etc, while the secondary equipments include protection, control andCommunication equipments.Levels of Sub-Station Automation: Sub-station Automation systems comprise threeLevelsThe station level: It consists of the station computer with a database, operator’sworkplace, and interfaces for remote communication etc. Station Level functions referto the substation as a whole.There are two classes of station level functions namely the process related stationlevel function and the interface related station level function.The Process related functions act on the data from multiple bays or substationlevel database. These functions are used to submit the control commands for theprimary equipment (Circuit breakers) and collect the substation data like voltage,current, power factor etc. from the bay level devices. As described above, each bayincludes one primary equipment such as transformers, feeders etc. Interface relatedfunctions enable interactive interface of the substation automation system to the localstation operator HMI (Human Machine Interface), to a remote control centre or to theremote monitoring centre for monitoring and maintenance. 17BSES Page 13
  18. 18. SUBSTATION AUTOMATIONThe Bay level: It comprises of all the control and protection units and the processlevel with more or less intelligent process interfaces to the field equipments. Extendedimplementations show all three levels equipped with IEDs, There is not only verticalcommunication between the levels (e.g. between bay and station level), but alsohorizontal communication within the level (e.g. in the bay level between bay units forfunctions like interlocking).Bay level functions are using mainly one bay and acting mainly on the primaryequipment of one bay. The definition of bay level functions considers some kind of ameaningful substructure in the primary substation configuration and related to thissubstructure, some local functionality or autonomy in the secondary system.Examples for such functions are line protection or bay control. These functionscommunicate within the bay level and process level.The Process Level Function: Its main task is to extract the information fromswitchgear / CTs / VTs in the substation and to send them to upper level device,called bay level device. The other major task of process level function is to receive thecontrol command from bay level device and execute it at appropriate switch level.The initial advent of digital substations was followed by a rapid evolution ofsoftware technology. Substation automation systems formed out of distributedcomponents is a technological possibility made viable by the IEC 61850 standard“Communication Networks and Systems in Substations”.Substation automation basically consists of implementing intelligent electronicdevices (IEDs) using microprocessors to monitor and control the physical powersystem devices. These IEDs can make more data available in digital format. However,these data can be turned into information that is available in the right form, at the right place,and at the right time through automation. It is this information that is the truebenefit of substation automation.Substation automation offers implementation benefits as enumerated below:-(a) Reduced quantities of equipment, networks implemented with fiber-optic cable, industrystandard interface technology – Ethernet, Data management, Metadata management,designing toward a seamless architecture, Integration of digital information and functionality,Gradual displacement of analog devices, new digital equipment capabilities and Station HMIconsoles. 18BSES Page 14
  19. 19. SUBSTATION AUTOMATION(b) Substation automation benefits the utility staff, Maintenance staff, Planner, Assetmanagement personnel, Operators and operational planners, Protection engineers,Operations engineers, Data administrators.(c) Substation automation benefits control center operations, SCADA/EMS systems,Contingency analysis (security analysis), and intelligent alarm processing, Emergency responseetc. 19BSES Page 15
  20. 20. SUBSTATION AUTOMATIONRelay to Relay Legacy communication ArchitectureEach relay to relay requires a dedicated link and change in relay behavior requiresrewiring as shown in figure 3. Also, one cannot know the status of the links if it isworking or not unless it is used. The dedicated application can only access data fromthe IEDs. Addition of new device needs modification in the common data path suchas need to add driver specific to the new device, add an entry into tag database and tomodify the application if required. 20BSES Page 16
  22. 22. SUBSTATION AUTOMATION REMOTE TERMINAL UNITThe RTU or the Remote Terminal Unit is one of the components that comprise the SCADAsystem. It is located in the field and it acts as an interface between the CR Panels and theMaster Control Center. It gathers information that is present in the field and its sends it to theMCC. Similarly, it executes the command that come from the MCC. So, we see that it is a two-way communication device that keeps updating the status of the field continually andsimultaneously executing the commands from the Control Center.If one takes a closer look at the RTU, one can see two different types of Panels. One, housing astack of racks called the “RTU Panel” and the other housing only the MFMS or MultifunctionMeters, called the “MFM panel”.The RTU panel consists of a 1. Basic Rack 2. Extension RacksBasic Rack: - The Basic rack or the Communication Sub Rack houses the brain of the RTU. Itconsists of a number of slots. Into these slots are inserted a set of “Cards”. The Cards are theCPUs of the RTU. They help in coordinating the flow of data from and into the RTU. TheseCPUs are basically of two types:-SLI (Serial Line Interface) CardsThe SLI Card acts as an interface between the RTU and the IEDs (Intelligent Electronic Devices).It continually reads data in and out of the IEDs. These IEDs could either be Numerical Relayspresent on the CR Panel or an MFM placed on the MFM panel of the RTU It is generally placedin a slot of the Basic Rack. The SLI card has got a provision for communicating with the IEDsthrough four ports, A, B, 1 and 2. The port A and B are of the RS485 type where 1 and 2 are ofthe RS232. The SLI card has an MMI port for handling the dialogue between the web browserand the RTU. 22BSES Page 18
  24. 24. SUBSTATION AUTOMATIONETH (Ethernet) CardsThe ETH card controls the process events and communications with the Control Centers. Itcontinually reads the data from the Extension Racks, the SLI cards and sends it to the controlcenter. The ETH card has a port “E”, which is used by the RTU to communicate to the Master.The ETH is connected to the Extension Rack through port A or B, called COM A and COM B. Italso has an MMI port similar to the one present in the SLI card, for handling the dialoguebetween the RTU and the web browser.The ETH and the SLI cards communicate with each other through a dedicated communicationchannel present on the back plane of the Basic Rack.SERIAL LINE INTERFACE 560 ETHERNET ADAPTER 560 24BSES Page 20
  25. 25. SUBSTATION AUTOMATIONExtension Racks: - The Extension rack is a place, which is used to house the Input/outputModules of the RTU. Similar to the structure of the Basic Rack, the Extension rack has slots intowhich the I/O modules can be inserted (unlike CPUs in the case of Basic Rack). The extensionrack communicates only with the ETH card of the Basic Rack. In cases where there are morethan one extension racks, each communication port of the extension rack is looped with theone succeeding it. As mentioned before, the extension rack is connected to the ETH throughport A or B, called COM A and COM B.The I/O or Input/output modules are located in the Extension rack. The function of the InputModules is to send the status of the equipment present in the grid station to the MCC. Thefunction of the output modules is to control the status of the equipment from the MCC. Thus,we see that the flow of data, in the case of input modules, is from RTU to MCC and from MCCto RTU in the case of Output modules. RTU 560 RACKS 25BSES Page 21
  26. 26. SUBSTATION AUTOMATIONThe different type of I/O modules used are theDI cards – 23BE21The DI cards have 16 channels, which can be used for indications. If one takes a look at thefront face of the DI card, one can see 16 LEDs. Each LED indicates a particular status at thefield.AI cards – 23AE21The AI card on the other hand gives the analog value of the signal. It has 16 channels on whicheight signals can be configured. The input to a channel in the AI card is a 4-20ma dc current,which is proportional to the range of the analog value.DO cards – 23BA20The DO card is used to execute commands that are sent from the MCC. As soon as the DO cardgets a command from the MCC, it sends a pulse of 48v dc to the exciting terminals of thecontactor. As soon as the contactor gets this pulse it closes its contacts and the command getsexecuted. There is a contactor dedicated to execute a particular command. 26BSES Page 22
  27. 27. SUBSTATION AUTOMATIONMFM PANEL: -The MFM Panel consists of MFMs. On the Panel cutouts are made pertaining to the size of theMFMs. The MFMs are then inserted into the cutouts and are tightly clamped. As mentionedbefore, the MFM is an IED and it communicates with the MCC through the SLI card.The MFM has 12 terminals to which connections have to be provided.2 are for auxiliary supply,4 are for PT secondary, and6 are for CT secondary.Apart from these terminals, the MFM has a Communicable port and a port to which a handheld programmable and display unit can be connected.The MFM is an IED that can calculate values once the inputs from the secondary of the CTs andPTs have been given. Each MFM is dedicated to a particular panel, be it, outgoing or incoming.The MFM calculates and displays values on a hand held programming and display unit. Thesevalues depend on the programmed primary value corresponding to the CT and PT ratio,pertaining to that feeder. 27 MFMBSES Page 23
  28. 28. SUBSTATION AUTOMATIONIncreasing capabilities of decentralized control and closed-loop control solutions allows to runmore functions to be done in the station directly. The RTU560 supports this by own PLCprograms which may use for control tasks on one side and by the capability to communicatewith the external control, protection and monitoring units via serial lines on the other side.The RTU560 will distribute process information from these units on the demands for station-and network control to several network control centers (NCC).The RTU560 is using a set of communication units (CMU) and I/O boards with a goodmodularity to build up the RTU configurations optimized for the application and data pointprofile in the station. Starting with a configuration for some I/O process data points and onecommunication unit for typical small pump stations or ring main unit stations over mediumsize stations for distribution up to large stations on transmission grid level.The engineering work is a relevant cost factor that can be reduced by standardization of theprocess data model and the use of state-of-the-art engineering tools. The tool must support alltype of configurations and communication network for telecontrol which are possible by theRTU560 family and the customers demand for the distributed stations.Engineering of the process signals for the RTU560 is done by means of only one tool RTUtil560 for all stations with RTU560 units and projects. Project is here in the definition of atelecontrol network with several remote stations combined by router stations etc. RTUtil 560supports process signal routing from a small station on the lowest level up to the highest levelfor network control centers (NCC). Typically it includes the conversion from a telecontrolprotocol A to another telecontrol protocol B used on the next level. For example from DNP3.0 to IEC 870-5-104. RTUtil 560 generates all files requested to run the RTU560 units. Toreduce traveling costs and to get a higher flexibility for configuration extensions ormodifications, RTUtil 560 and the RTU560 concept allows to download the files into theRTU560 in the stations via INTRANET using WEB browser technology or via the communicationline, when the protocol supports file transfer. 28BSES Page 24
  29. 29. SUBSTATION AUTOMATION FeaturesThe telecontrol system RTU560 should be in the position to transmit nearly all kind of processinformation, derived from various units in the station, to the control centers and to marshalcommands received from the control centers to the addressed control unit within the station.Beside the acquisition and processing of the directly parallel wired process signals to theRTU560 IO-process interface, the RTU560 is designed for the link of serial communicationroutes within the station as well to the higher control level. This can be another RTU560 routerstation or a network control center. Within the station it is the connection of other existingadditional control, protection or monitoring devices (Intelligent Electronic Devices = IED) viaserial interfaces.The RTU560 concept allows the economical adaptation to the requested, different serial linksby cascading the communication and processing units (CMU=Communication Unit) accordingto the number of needed serial interfaces.Functional system features of the RTU560 to fulfill the requirements for remote controlstations:• High functional scope for telecontrol applications functions• PLC capabilities to execute control and closed loop control applications for pump stations,hydro power plants, station interlocking for electrical substations, etc..• Archiving of process and station events in a sequence of events list in the Flash memory.Accessible via Intranet or equivalent independent network.• Archiving of Integrated Totals (ITI) and Analog Measured Values (AMI) in the Flash memory.Accessible via Intranet or equivalent independent network.• Reading and archiving of disturbance files from protection relays on request of theprotection relay. Reading of the disturbance files by file transfer over a separatecommunication network (e.g. Intranet) on users demand. Independent and direct informationof available new disturbance files in the disturbance file archive to the NCC.• Possibility to build (engineer) group alarms for the typical alarm messages, beside a PLCprogram.• Marshalling and filtering process events to the connected NCCs . Decoupling transactionsequences and delay times to the different NCCs by using a separate process data base perNCC link.• Remote access for diagnostic purposes via Web-Browser and Internet or Intranet. Withdetailed information down to each process signal.• Integrated HMI (Human Machine Interface ) for process super vision and control. Via Web-Browser and Internet or Intranet. 29BSES Page 25
  30. 30. SUBSTATION AUTOMATION FIG: Typical configuration of a telecontrol system 30BSES Page 26
  31. 31. SUBSTATION AUTOMATION COMMUNICATION SUBSYSTEMThere are two types of communication we are usingINTERNAL COMMUNICATIONServer client and server-server communication is in general on a publish-suscribe and event-driven basis and uses a TCP/IP protocol, i.e. a client application subscribes to a parameterwhich is owned by a particular server application and only changes to that parameter are thencommunicated to the client application.ACCESS TO DEVICESThe data server polls the controllers at a user defined polling rate. The polling rate may bedifferent for different parameters to the data servers. Time stamping of the processparameters is typically performed in the controllers and this time-stamp is taken over by thedata server. If the controller and communication protocol used support unsolicited datatransfer then the product will support this too. The product provides communication driversfor most of common PLC’s and widely used field buses, e.g. Modbus. A single data server cansupport multiple communication protocols as it has slots for interface cards. 31BSES Page 27
  32. 32. SUBSTATION AUTOMATIONFigure below shows the protocols used for communication Modbus Field Devices like CT, PT, Remote Relay that is C & R panel Terminal Unit IEC- 104 (608705104) TCP/IP Server PCU TCP/IP Work Station It is connected through several hundred RTU’s depending upon the requirements. So there is continuous flow of data between RTU and PCU. This is called hand shaking mode. 32BSES Page 28
  33. 33. SUBSTATION AUTOMATION TYPES OF CONNECTIVITYDedicated Links: -Reserved for a specific use. In communication, a dedicated channel is the line reservedexclusively for one type of communication. This is same as a leased line or a private line. a) Leased Line/E1 interface: Leased lines are dedicated circuits provided by Basic Service Providers (BSPs), which provide permanent connectivity to the Internet. Leased lines provide the last mile access from the user premises to the ISP. They provide permanent connection as compared to the temporary connectivity through dialup access. The quality of the connection is far superior to what is normally available through dialup, thanks to digital signaling, less noise, fewer exchanges etc. Leased lines provides a scalable access method, important particularly for organizations with large user groups, including corporate, banks and financial institutions, educational and R&D organizations, government, military etc. Starting typically with 64 Kbps, it is possible to deploy a scalable architecture, with multiples of E1 (2 MBPS) pipes, providing the necessary bandwidth. In fact, leased access becomes a must for large organizations in most situations. b) Optical Fiber Connectivity: An optical fiber is made up of the core (carries the light pulses), the cladding (reflects the light pulses back into the core) and the buffer coating (protects the core and cladding from moisture, damage, etc). Together, all of this creates a fiber optic which can carry up to 10 million messages at any time using light pulses. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-optic communications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. Reliance Infocomm provides Optical Fiber Connectivity to BSES. 33BSES Page 29
  34. 34. SUBSTATION AUTOMATION c) LMDS (Local Multiple-Point Distribution service): This is a fixed wireless technology that operates in the 28 GHz band and offers line of sight coverage over distances up to 3-5 kilometers. It can deliver data and telephony services to 80,000 customers from a single node. LMDS is one solution for bringing high bandwidth services to homes and offices within the “last mile” of connectivity, an area where cable or optical fiber may not be convenient or economical. Data transfer rates for LDMS can 1.5 Gbps to 2Gbps, but more realistic value may average around 38 Mbps(downstream).SATELLITE LINK:- a) Very Small Aperture Terminal (VSAT):- VSAT is a satellite communications system that serves home and business users. A VSAT end user needs a box that interfaces between the user’s computer and an outside antenna with a transceiver. The transceiver receives or sends a signal to a satellite transponder in the sky. The satellite sends and receives signals from an earth station computer that acts as a hub for the system. VSATs access satellite in geosynchronous orbit to relay data from small remote earth stations (terminals) to other terminals (in mesh configurations) or master earth station "hubs" (in star configurations). VSATs are most commonly used to transmit narrowband data (point of sale transactions such as credit card, polling or RFID data; or SCADA), or broadband data (for the provision of Satellite Internet access to remote locations, VoIP or video). VSATs are also used for transportable, on-the-move (utilizing phased array antennas) or mobile maritime communications. b) Leased line: - A leased line connects two locations for private voice and/or data telecommunication service. Not a dedicated cable, a leased line is actually a reserved circuit between two points. Leased lines can span short or long distances. They maintain a single open circuit at all times, as opposed to traditional telephone services that reuse the same lines for many different conversations through a process called "switching." Leased lines most commonly are rented by businesses to connect branch offices, because these lines guarantee bandwidth for network traffic. So-called T1 leased lines are common and offer the same data rate as symmetric DSL (1.544 Mbps). Individuals can theoretically also rent leased lines for high-speed Internet access, but their high cost 34BSES Page 30
  35. 35. SUBSTATION AUTOMATION (often more than $1000 USD per month) deters most. Fractional T1 lines, starting at 128 Kbps, reduce this cost somewhat and can be found in some apartment buildings and hotels.A leased line is service contract between a provider and a customer, whereby the provideragrees to deliver a symmetric telecommunications line connecting two locations in exchangefor a monthly rent (hence the term lease). It is sometimes known as a Private Circuit or DataLine in the UK or as CDN (Circuito Diretto Numerico) in Italy. Unlike traditional PSTN lines itdoes not have a telephone number, each side of the line being permanently connected to theother. Leased lines can be used for telephone, data or Internet services. Someareringdown services, and some connect two PBXes.A permanent telephone connection between two points set up by a telecommunicationscommon carrier. Typically, leased lines are used by businesses to connect geographicallydistant offices. Unlike dial-up connections, a leased line is always active. The fee for theconnection is a fixed monthly rate. The primary factors affecting the monthly fee are distancebetween end points and the speed of the circuit. Because the connection doesnt carryanybody elses communications, the carrier can assure a given level of quality.An internet leased line is a premium internet connectivity product, delivered over fibrenormally, which is dedicated and provides uncontended, symmetrical speeds. It is also knownas an ethernet leased line, DIA line, data circuit or private circuit. Reference taken from Vaioni. 35BSES Page 31
  36. 36. SUBSTATION AUTOMATIONLeased line Technology presently used at BSES, DelhiThe E1 standard is followed in the European countries. The E1 interface provides a 2048 kbpsaccess rate. It can support up to 32 user channels, each of 64 Kbps access rate, though mostlyonly 30 are used as dedicated user channels. The E1 interface supports several mechanisms forsynchronization, error correction and detection, management and performance messages andsignaling. BSES SCADA PCM MLDN MODEM OFC MDF OFCROUTER ROUTER STM-1 LOCAL EXCHANGE SITE END LOCALSWITCH MTNL SWITCH LAN 36BSES Page 32
  37. 37. SUBSTATION AUTOMATION VSATThe BSES use the VSAT satellite link as a backup for its network. HECL is the service provider ofVSAT. The replying time of this satellite link is very high but it is a very reliable link. Low costbusiness terminals with small antennas (generally less than 2 meters in diameter) are oftentermed Very Small Aperture Terminals (VSAT). These are usually perceived as being two-waydata terminals, though strictly speaking many of the systems used for data broadcast are reallyone-way VSAT. Taking the USA as an example, approximately half of all installed VSAT are onlyused for one way data links. Very Small Aperture Terminal (VSAT), is a two-way satellite ground station or astabilized maritime VSAT antenna with a dish antenna that is smaller than 3 meters. Themajority of VSAT antennas range from 75 cm to 1.2 m. Data rates typically range from 56Kbit/s up to 4 Mbit/s. VSATs access satellites in geosynchronous orbit to relay data from smallremote earth stations (terminals) to other terminals (in mesh configurations) or master earthstation "hubs" (in star configurations).VSATs are most commonly used to transmit narrowband data (point of sale transactions suchas credit card, polling or RFID data; or SCADA), or broadband data (for the provision of SatelliteInternet access to remote locations, VoIP or video). VSATs are also used for transportable, on-the-move (utilizing phased array antennas) or mobile maritime communications.ConfigurationsMost VSAT networks are configured in one of these topologies: A star topology, using a central uplink site, such as a network operations center (NOC), to transport data back and forth to each VSAT terminal via satellite, A mesh topology, where each VSAT terminal relays data via satellite to another terminal by acting as a hub, minimizing the need for a centralized uplink site, A combination of both star and mesh topologies. Some VSAT networks are configured by having several centralized uplink sites (and VSAT terminals stemming from it) connected in a multi-star topology with each star (and each terminal in each star) connected to each 37BSES Page 33
  38. 38. SUBSTATION AUTOMATION other in a mesh topology. Others configured in only a single star topology sometimes will have each terminal connected to each other as well, resulting in each terminal acting as a central hub. These configurations are utilized to minimize the overall cost of the network, and to alleviate the amount of data that has to be relayed through a central uplink site (or sites) of a star or multi-star network. Initially the use of VSAT antennas at sea was for transmission of television signals. One of the first companies to manufacture stabilized VSAT antennas was SeaTel of Concord, California which launched their first stabilized antenna in 1978. Sea Tel dominates the supply of two-way VSAT stabilized antenna systems to the marine market with almost 72 per cent of the market in 2007 compared with Orbit’s 17.6 per cent. Initially maritime VSAT was using Single Channel per Carrier - SCPC technology - which suited large volume users like oil drilling rigs and oil platforms and large fleets of ships from one ship-owner sailing within one or few satellite footprints. This changed when the company iDirect launched its IP-based Time Division Multiple Access (TDMA) technology that dynamically allocated bandwidth to each ship for shared bandwidth, lowering the entry level cost for getting maritime VSAT installed, which turned out to be of key importance to small-to mid-sized fleets, and thus to the market acceptance of VSAT. VSAT’S STRENGTH VSAT technology has many advantages, which is the reason why it is used so widely today. One is availability. The service can basically be deployed anywhere around the world. Also, the VSAT is diverse in that it offers a completely independent wireless link from the local infrastructure, which is a good backup for potential disasters. Its deployability is also quite amazing as the VSAT services can be setup in a matter of minutes. The strength and the speed of the VSAT connection being homogenous anywhere within the boundaries is also a big plus. Not to forget, the connection is quite secure as they ar private layer-2 networks over the air. The pricing is also affordable, as the networks themselves do not have to pay a lot, as the broadcast download scheme (eg. DVB-S) allows them to serve the same content to thousands of locations at once without any additional costs. Last but not least, most of the VSAT systems today use onboard acceleration of protocols (eg. TCP, HTTP), which allows them to delivery high quality connections regardless of the latency. 38BSES Page 34
  39. 39. SUBSTATION AUTOMATIONVSATs DrawbacksAs with everything, VSAT also has its downsides. Firstly, because the VSAT technology utilizesthe satellites in geosynchronous orbit, it takes a minimum latency of about 500 millisecondsevery trip around. Therefore, it is not the ideal technology to use with protocols that require aconstant back and forth transmission, such as online games. Also, surprisingly, theenvironment can play a role in slowing down the VSATs. Although not as bad as one way TVsystems like DirecTV and DISH Network, the VSAT still can have a dim signal, as it still relies onthe antenna size, the transmitters power, and the frequency band. Last but not least,although not that big of a concern, installation can be a problem as VSAT services require anoutdoor antenna that has a clear view of the sky. An awkward roof, such as with skyscraperdesigns, can become problematic.Typical applications for interactive VSAT networks are:  Computer communications;  Reservation systems;  Database enquires;  Billing systems;   File transfers;  Electronic mail;  Video conferencing;  Point of sale transactions;  Credit checks and credit card verification; Stock control and management. 39BSES Page 35
  40. 40. SUBSTATION AUTOMATIONThe most common VSAT configuration is the TDM/TDMA star network. These have a high bitrate outbound carrier (TDM) from the hub to the remote earth stations, and one or more lowor medium bit rate Time Division Multiple Access (TDMA) inbound carriers.With its star configuration network architecture, interactive VSAT technology is appropriatefor any organization with centralized management and data processing.This configuration has been developed to minimize overall lifetime costs for the completenetwork including satellite transmission costs. The use of a single high performance hub allowsthe use of low cost remote VSAT terminals and optimizes use of satellite capacity. Even so, inmost VSAT networks, the cost of the VSAT terminals usually far exceeds the cost of the hub(typically a VSAT terminal is 0.1 to 0.2% of the price of the hub).In a typical VSAT network, remote user sites have a number of personal computers, dumbterminals and printers connected to the VSAT terminal which connects them to a centralizedhost computer either at the organization’s head office or data processing centre. Data sent tothe VSAT terminal from the DTEs is buffered and transmitted to the hub in packets. 40BSES Page 36
  41. 41. SUBSTATION AUTOMATIONShared Hub NetworksTo make VSAT networks more affordable it is possible to share the hub between several users,thereby spreading the cost. In this case the hub is usually owned by a service provider whoretains overall control of the network and who manages the hub itself.Each user, however, is allocated his own time slots or carriers and can so operate his ownprivate network using the shared hub facility without any loss of privacy. The operation andmanagement of these sub networks is performed by the users themselves completelyindependently of the service supplier. 41BSES Page 37
  42. 42. SUBSTATION AUTOMATION CONTROL CENTRE SUBSYSTEM WORK STATIONWork station is nothing but the control room itself. In BSES there are four monitors which areused for the display of: 1. Delhi power summary (Delhi SLDC and NRLDC Data’s from web sites) 2. Single line diagram of the grid 3. Alarms and Event list 4. OMS-Outage management 42BSES Page 38
  43. 43. SUBSTATION AUTOMATIONEVENT LISTAn event list is a historical record of events, chronologically presented, where each event has atime stamp and a description 43BSES Page 39
  46. 46. SUBSTATION AUTOMATION DESIGNING OF SINGLE LINE DIAGRAMS (DATA ENGINEERING)Single line diagram (SLD)The first step in planning a substation layout is the preparation of a one-line diagram whichshows in simplified form the switching and protection arrangement required, as well as theincoming supply lines and outgoing feeders or transmission lines. It is a usual practice by manyelectrical utilities to prepare one-line diagrams with principal elements (lines, switches, circuitbreakers, and transformers) arranged on the page similarly to the way the apparatus would belaid out in the actual station.Incoming lines will almost always have a disconnect switch and a circuit breaker. In somecases, the lines will not have both; with either a switch or a circuit breaker being all that isconsidered necessary. A disconnect switch is used to provide isolation, since it cannotinterrupt load current. A circuit breaker is used as a protection device to interrupt faultcurrents automatically, and may be used to switch loads on and off. When a large fault currentflows through the circuit breaker, this may be detected through the use of currenttransformers. The magnitude of the current transformer outputs may be used to trip thecircuit breaker resulting in a disconnection of the load supplied by the circuit break from thefeeding point. This seeks to isolate the fault point from the rest of the system, and allow therest of the system to continue operating with minimal impact. Both switches and circuitbreakers may be operated locally (within the substation) or remotely from a supervisorycontrol center.Once past the switching components, the lines of a given voltage connect to one ormore buses. These are sets of bus bars, usually in multiples of three, since three-phase electrical power distribution is largely universal around the world.The arrangement of switches, circuit breakers and buses used affects the cost and reliability ofthe substation. For important substations a ring bus, double bus, or so-called "breaker and ahalf" setup can be used, so that the failure of any one circuit breaker does not interrupt powerto branch circuits for more than a brief time, and so that parts of the substation may be de- 46BSES Page 42
  47. 47. SUBSTATION AUTOMATIONenergized for maintenance and repairs. Substations feeding only a single industrial load mayhave minimal switching provisions, especially for small installations.Once having established buses for the various voltage levels, transformers may be connectedbetween the voltage levels. These will again have a circuit breaker, much like transmissionlines, in case a transformer has a fault (commonly called a short circuit).Along with this, a substation always has control circuitry needed to command the variousbreakers to open in case of the failure of some component.Special features include: Automatic checking of all circuit connections Automatic assignment of colors to different voltage levels Zoom in and zoom out facility Group copying, deletion and movements of objects Navigation map Grid layout Easy location of a user specified equipments Functions controlled either mouse or keyboardDesigning of single line diagrams is done using software DE400, pad and WS500. Rough designis done using subnets and bays in DE400. Initial step is to select a subnet for a particular Busbar e.g. LT line, HT line. Next, bay is selected for individual elements to be connected with thebus bar such as circuit breaker, CT & PT, isolators and earthing isolators. It means bay is asubpart of subnet. For power transformers individual subnets are selected.Now this image is presented in a pad where further modification is carried out by locatingcorrect position for spring of circuit breaker, transformer connection etc. and finally it isplaced in WS500.WS500 is the user interface for the Network Manager system and is a proven tool for thedemanding real-time control of geographically distributed process. 47BSES Page 43
  48. 48. SUBSTATION AUTOMATIONIn addition, by supporting ABB’s industrial IT, the WS500 also performs Aspect and Objectnavigation. This adds more flexibility by making it possible to add object-specific userfunctionality.WS500 features: State of the art Microsoft Windows look and feel with Multi Document Interface (MDI) support. Personal online configurable menus, toolbars and color palettes included in operator settings. Unique document concept for combining traditional process displays with web pages and any ActiveX-based components as display documents. Low bandwidth requirements. Unique display sub-division and automatic run-time local cashing mechanism for fast call up times, even over serial modem connections. Support of all types of character Unicode’s. Context-sensitive help, on-line help and tool tips. 48BSES Page 44
  50. 50. SUBSTATION AUTOMATION PROCESS COMMUNICATION UNITPCU400 is used for flexible and effective data acquisition in SCADA systems.The PCU400 handles communication with RTUs, IEDs and Substation Automation System. Itprovides flexibility, performance and scalability in a cost-effective manner. PCU400 supports anumber of different protocols. Each unit connects up to 64 asynchronous communication linesat rates up to 64 Kbit/s.PCU400 features: Different protocols configured per communication channel Bit-oriented protocols with OCC2-8 hardware Cyclic scanning of RTUs and scan groups Reduces SCADA server I/O overhead Connected to servers via LAN/WAN (TCP/IP), dual LAN Performs dead-band-based report-by-exception of data to the SCADA server Data engineering with SCADA engineering tool or Excel-based toolPCU400 is the modern product when implementing effective data acquistion with NetworkManager.PCU400, Process Communication Unit 400 forms the communication interface to the networkof remote terminal units (RTUs) together with the Remote Communication Server, RCS,located in the application server of a Network Manager SCADA system. The PCU400 can beused as a SCADA front-end, communication gateway for Substation Automation systems or asa standalone protocol converter. Two parts define the Data Acquisition system: RCS Application, a software package running in the Application Server PCU400, a front-end converter that implements the protocols and connects the physical linesPCU 400 can be used in a variety of configurations to cater for different network topologiesand different levels of fault tolerance in the system. The alternatives include single orredundant PCU 400 units. 50BSES Page 46
  52. 52. SUBSTATION AUTOMATION ADVANTAGES OF SCADAAfter doing automation of grid basically we have increased the efficiency of electricitydistribution. There are some other methods which help in identifying the loss making zonesand overall improving the efficiency of distributions: 1. Automation of substation grid 2. Automated meter reading(AMR) 3. Geographical information system(GIS) 4. Energy audit and accounting 5. LT-ABC 6. High voltage distribution system(HVDS) 52BSES Page 48