1. SOUTHERN REGIONAL LOAD DESPATCH CENTER POWERGRID, BANGALORE Data Acquisition & Communication Abhimanyu Gartia Chief Manager,SCADA-IT SRLDC

2. Instrumentation For SCADA Transducers Transducers Transducers RTU RTU RTU Current Transformer Current Transformer Current Transformer Current Transformer Capacitor Voltage Transformer Capacitor Voltage Transformer Capacitor Voltage Transformer Capacitor Voltage Transformer

3. TRANSDUCER Device converts one form of energy to another form. Device converts one form of energy to another form. Energy form viz. electrical, mechanical, chemical etc. Energy form viz. electrical, mechanical, chemical etc. Transforms High level to Low level Transforms High level to Low level Input – Hundreds of volt Input – Hundreds of volt Output – Few milliamperes Output – Few milliamperes Measures field parameters like voltage, frequency, current, 3 phase bi directional active & reactive power and transformer tap position Measures field parameters like voltage, frequency, current, 3 phase bi directional active & reactive power and transformer tap position Accuracy : +/- 0.2% class for frequency transducers and +/- 0.5% class for other transducers Accuracy : +/- 0.2% class for frequency transducers and +/- 0.5% class for other transducers

4. TRANSDUCER TYPICAL RATING TYPICAL RATING Transducer Input Output Transducer Input Output Voltage 0-110 V 0-10 mA Voltage 0-110 V 0-10 mA Current 0-1 Amp 0-10 mA Current 0-1 Amp 0-10 mA 0-5 Amp 0-5 Amp Frequency 4-20 mA Frequency 4-20 mA MW 4-12-20mA MW 4-12-20mA MVAR 4-12-20mA MVAR 4-12-20mA

5. Remote Terminal Unit The RTU performs the data acquisition and supervisory control over the substation for the SCADA system. The RTU performs the data acquisition and supervisory control over the substation for the SCADA system. As a minimum, the RTU collects, processes and transmits the data from the substation to the control- centers. As a minimum, the RTU collects, processes and transmits the data from the substation to the control- centers. The following data are generally acquired from the sub- station:- The following data are generally acquired from the sub- station:- Analog- Power, Reactive Power, Voltage, Frequency, Current. Analog- Power, Reactive Power, Voltage, Frequency, Current. Digital- Circuit Breaker Status, Isolator Status,SOEs Digital- Circuit Breaker Status, Isolator Status,SOEs The RTU also receives and processes digital and analog commands. The RTU also receives and processes digital and analog commands.

6. RTU: MAIN FUNCTIONS SCADA SCADA Local Control Local Control Data Logging Data Logging Process Control Process Control

7. HARDWARE CONNECTIVITY DIAGRAM FOR SCADA AT SUBSTATION / GEN.STATION MAIN CPU BOARD PSU COMMN BOARD A N A L O G I / P D I G T A L I / P C O N T R O L O/P TERMINAL BLOCK TERMINAL BLOCK TERMINAL BLOCK REMOTE TERMINAL UNIT TRANSDUCER O/P TERMINAL MVARVOLTMW TRANSDUCER I/P TERMINAL P T SEC 110VAC CT SEC 1 AMPS FROMSWITCHYARD-FIELDFROMSWITCHYARD-FIELD EVENT LOGGER PANEL DRIVERDRIVER RELAYRELAY TRANSDUCER PANEL RS232 PORT

8. SCADA HARDWARE CONNECTIVITY WITH COMMUNICATION SYSTEM(PLCC) AT SUB-STN/GEN ST RTU N S K 5 modem PLCC T x / R x SPEECH / DATA PANEL RS 232 CONNECTIVITY PLCC INDOOR EQUIMENT

9. TRANSDUCERS CLASSIFICATION CLASSIFICATION SELF POWERED/AUXILARY POWERED SELF POWERED/AUXILARY POWERED INPUT INPUT VOLTAGE/CURRENT/POWER/POSITION VOLTAGE/CURRENT/POWER/POSITION OUTPUT OUTPUT 0-10mA, 4-20mA, 0-5mA 0-5v,0-10v 0-10mA, 4-20mA, 0-5mA 0-5v,0-10v OUTPUT IMPEDANCE OUTPUT IMPEDANCE 500Ω,1000Ω,2000Ω 500Ω,1000Ω,2000Ω ACCURACY ACCURACY 0.2 CLASS, 0.5 CLASS, CLASS 2 AND ABOVE 0.2 CLASS, 0.5 CLASS, CLASS 2 AND ABOVE

10. A/D CONVERSION AT RTU LEVEL (16 BIT ADC). FOR MW / MVAR TRANSDUCER: INPUT: PT SEC PHASE TO PHASE : 110VAC CT SEC TWO PHASE CURRENT (R & B): 1 AMPS. OUTPUT : 4 – 20mA(TRANSDUCER OUTPUT) IN ADC: AT 4mA = 6553 Count AT 20mA = 32767 Count 12mA IS THE CENTRE POINT. (+/- 0.1% IS THE ACCEPTABLE RANGE OF ERROR ON FULL SCALE) ( Ref Calculation Sheet for all type of Measurand)

11. TRANSDUCERS Measures field parameters like voltage, frequency, current, 3 phase bi directional active & reactive power and transformer tap position. Measures field parameters like voltage, frequency, current, 3 phase bi directional active & reactive power and transformer tap position. Rating Rating Vol: 110/115 volts phase to phase Vol: 110/115 volts phase to phase Current : 1 A Frequency: 45-55 Hz Output : 4 – 20 ma / 500 ohms Output : 4 – 20 ma / 500 ohms External power supply External power supply IEC 688 IEC 688 Accuracy : +/- 0.2% class for frequency transducers and +/- 0.5% class for other transducers Accuracy : +/- 0.2% class for frequency transducers and +/- 0.5% class for other transducers

12. SALIENT FEATURES OF ULDC RTU A small rugged computer A small rugged computer CPU, volatile & non-volatile memory, power supply module, I/O module CPU, volatile & non-volatile memory, power supply module, I/O module Communication ports & maintenance ports Communication ports & maintenance ports Allows the central SCADA master to communicate with the field devices Allows the central SCADA master to communicate with the field devices Acquires the data from the field devices/equipment and transfers the data to the SCADA system Acquires the data from the field devices/equipment and transfers the data to the SCADA system Distributed Processing Technology Distributed Processing Technology Main processor is 32-Bit 16Mhz and sub modules are 8- bit. Main processor is 32-Bit 16Mhz and sub modules are 8- bit. Real time clock Real time clock Access via PC-Based Configuration. Access via PC-Based Configuration. Password Protected. Password Protected. Database configured via a PC and can be downloaded Database configured via a PC and can be downloaded

13. SALIENT FEATURES OF ULDC RTU Switch mode converter power supply module which provides power for mother board, VME cards, I/O modules and peripherals. Input voltage – 241 V AC, 50 Hz. Outpit voltage +/-5V DC, +/- 12 V DC, +/- 24 V DC Switch mode converter power supply module which provides power for mother board, VME cards, I/O modules and peripherals. Input voltage – 241 V AC, 50 Hz. Outpit voltage +/-5V DC, +/- 12 V DC, +/- 24 V DC 32 Analog inputs per module,15 bit resolution. 32 Analog inputs per module,15 bit resolution. Conversion rate 660 ns for all 32 inputs. Conversion rate 660 ns for all 32 inputs. 64 status inputs per status module,1ms scan time for 64 inputs,1ms SOE resolution. A simple status input/SOE input/accumulator input can be connected. LED indicators for each input. Contact wetting voltage supplied by power supply module. 64 status inputs per status module,1ms scan time for 64 inputs,1ms SOE resolution. A simple status input/SOE input/accumulator input can be connected. LED indicators for each input. Contact wetting voltage supplied by power supply module. 32 control output per control module. Two master relays for each output. One for close and one for trip. 32 control output per control module. Two master relays for each output. One for close and one for trip. Through the maintenance port, we can download the database, view data and Communications specific to each peripheral board and trouble shoot. Through the maintenance port, we can download the database, view data and Communications specific to each peripheral board and trouble shoot. Advanced diagnostic capabilities Advanced diagnostic capabilities Time synchronisation of RTU done at every 1 minute. Time synchronisation of RTU done at every 1 minute.

14. Scan Cycles All the analog data are scanned every 10/12 seconds All the analog data are scanned every 10/12 seconds Status information are reported by exception Status information are reported by exception All status information are scanned for integrity check every 10 minutes All status information are scanned for integrity check every 10 minutes The SOE datas are time stamped at 1 ms resolution The SOE datas are time stamped at 1 ms resolution Time synchronisation is done every 10 minutes Time synchronisation is done every 10 minutes

15. Current Transformer A current transformer is a measurement device designed to provide a current in its secondary coil proportional to the current flowing in its primary. A current transformer is a measurement device designed to provide a current in its secondary coil proportional to the current flowing in its primary. The current transformer isolates measurement and control circuitry from the high voltages typically present on the circuit being measured. The current transformer isolates measurement and control circuitry from the high voltages typically present on the circuit being measured. Common secondary are 1 or 5 amperes. For example, a 4000:5 CT would provide an output current of 5 amperes when the primary was passing 4000 amperes. Common secondary are 1 or 5 amperes. For example, a 4000:5 CT would provide an output current of 5 amperes when the primary was passing 4000 amperes.

16. Capacitor Voltage Transformer Capacitor Voltage transformers (CVTs) are used for metering and protection in high- voltage circuits. They are designed to present negligible load to the supply being measured and to have a precise voltage ratio to accurately step down high voltages so that metering and protective relay equipment can be operated at a lower potential. Capacitor Voltage transformers (CVTs) are used for metering and protection in high- voltage circuits. They are designed to present negligible load to the supply being measured and to have a precise voltage ratio to accurately step down high voltages so that metering and protective relay equipment can be operated at a lower potential.

17. Basic Function Of the CVT Where CHF is the equivalent rated capacitance for carrier communication Where CHF is the equivalent rated capacitance for carrier communication * C1 : High Voltage capacitor * C1 : High Voltage capacitor * C2 : Intermediate Voltage * C2 : Intermediate Voltage Capacitor Capacitor * C1 / C2 ratio is such that the required intermediate voltage can be achieved * C1 / C2 ratio is such that the required intermediate voltage can be achieved L : Inductance of the choke which is designed to L : Inductance of the choke which is designed to * Prevent carrier signals from flowing into the transformer circuit. * Prevent carrier signals from flowing into the transformer circuit. * Resonate with the capacitor unit at 50 Hz which is the rated frequency. * Resonate with the capacitor unit at 50 Hz which is the rated frequency. D : Damping burden which is provided across one of the secondary windings to prevent terroresonance oscillations. D : Damping burden which is provided across one of the secondary windings to prevent terroresonance oscillations. Tr : Transformer designed to provide the required output voltage at the desired burden Tr : Transformer designed to provide the required output voltage at the desired burden Metering Protection D 1a 1n 2a 2n HV C1 C2 Tr L CHF

18. COMMUNICATION REQUIREMENTS FOR SCADA

19. Communication media should have: Communication media should have: * High Reliability * High Reliability * High Availability * High Availability * Rapid Response * Rapid Response * Transparency * Transparency * Economy * Economy * Flexibility * Flexibility * Maintainability * Maintainability

20. Modes of Communication Modes of Communication PLCC PLCC PLCC Leased Telephone circuits Leased Telephone circuits Leased Telephone circuits Leased Telephone circuits Microwave Communication Microwave Communication Microwave Communication Microwave Communication Fibre Optics Communication Fibre Optics Communication Fibre Optics Communication Fibre Optics Communication Satellite Communication Satellite Communication Satellite Communication Satellite Communication

21. PLCC High voltage lines themselves are used as communication links. High voltage lines themselves are used as communication links. Carrier Frequency: 50-300 KHz. Carrier Frequency: 50-300 KHz. 3 channels are used generally: 3 channels are used generally: Main-Channel -> Main-Channel -> speech channel – 300 Hz to 2000 Hz speech channel – 300 Hz to 2000 Hz Telemetring- 2000 Hz to 3400 Hz Telemetring- 2000 Hz to 3400 Hz Protection-Channel-I -> Protection-Channel-I -> speech channel – 300 Hz to 2000 Hz speech channel – 300 Hz to 2000 Hz Teleprotection- 2000 Hz to 3400 Hz Teleprotection- 2000 Hz to 3400 Hz Protection-Channel-II (Backup-Protection)-> Protection-Channel-II (Backup-Protection)-> speech channel – 300 Hz to 2000 Hz speech channel – 300 Hz to 2000 Hz Teleprotection- 2000 Hz to 3400 Hz Teleprotection- 2000 Hz to 3400 Hz

22. PLCC Advantages: 1. High reliability 2. All channels are available for dedicated use by power-utility alone power-utility aloneDisadvantages: 1. Cost of insulating communication equipment is high 2. High noise level due to Corona 3. High speed data-transfer not possible because of Bandwidth limitations. Bandwidth limitations.

23. Applications of PLCC Voice Communication Voice Communication Fascimile Transmission Fascimile Transmission Tele-Protection Tele-Protection Tele-Metering Tele-Metering

24. Types of Couplings 3 coupling schemes to couple voice, fax, tele-protection and tele-metering to the high-voltage transmission line: 3 coupling schemes to couple voice, fax, tele-protection and tele-metering to the high-voltage transmission line: Phase-to-Ground Coupling Phase-to-Ground CouplingPhase-to-Ground CouplingPhase-to-Ground Coupling Phase-to-Phase Coupling Phase-to-Phase CouplingPhase-to-Phase CouplingPhase-to-Phase Coupling Inter-Line Coupling Inter-Line CouplingInter-Line CouplingInter-Line Coupling

25. STATION-B PLCC PANELS STATION-A LMU ES LA DC CC WT PLCC PANELS ESLA DC CC WT PHASE-TO-GROUND COUPLING ES=Earth Switch DC=Drainage Coil WT=Wave Trap LA=Lightening Arrester LMU=Line Matching Unit CC=Coupling capacitor

26. STATION-B PLCC PANELS STATION-A LMU ES LA DC CC WT PLCC PANELS ESLA DC CC WT PHASE-TO-PHASE COUPLING ES=Earth Switch DC=Drainage Coil WT=Wave Trap LA=Lightening Arrester LMU=Line Matching Unit CC=Coupling capacitor BT=Balancing Transformer WT LMU BT LMU CC WT CC

27. STATION-B PLCC PANELS STATION-A LMU ES LA DC CC WT PLCC PANELS ESLA DC CC WT INTER-LINE COUPLING ES=Earth Switch DC=Drainage Coil WT=Wave Trap LA=Lightening Arrester LMU=Line Matching Unit CC=Coupling capacitor BT=Balancing Transformer LMU BT LMU CC

28. Microwave Communication Line-of-sight communication Line-of-sight communication Requires repeaters at 50-60 kms. Intervals Requires repeaters at 50-60 kms. Intervals Provides sufficient bandwidth to meet the needs of power utility Provides sufficient bandwidth to meet the needs of power utility Higher availability than PLCC, availablity not affected by maintenance or faults on the power lines Higher availability than PLCC, availablity not affected by maintenance or faults on the power lines Suffers from multipath-fading effect Suffers from multipath-fading effect In India, WPC (wireless planning & co-ordination) wing has assigned 2.3-2.5 GHz and 2.8-5 GHz bands to power sector usage. In India, WPC (wireless planning & co-ordination) wing has assigned 2.3-2.5 GHz and 2.8-5 GHz bands to power sector usage.

29. Digital Microwave Systems

30. Leased Telephone Circuits Simple solution, no need to develop own dedicated communication facility by power utility Availability of this mode of communication at remotely located substations is the deciding factor

31. Fiber-Optic Communication Fiber-optic communication is a method of transmitting information from one place to another by sending light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information Fiber-optic communication is a method of transmitting information from one place to another by sending light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information The process of communicating using fiber-optics involves the following basic steps: Creating the optical signal using a transmitter Relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak Receiving the optical signal and converting it into an electrical signal Analog/Digital Interface Voltage to Current converter Light Source Source to Fiber Interface Fiber to Light Detector Interface Light Detector Current to Voltage converter Analog/Digital Interface OUTPUT INPUT Optical Fiber

32. Fiber Optic Communication Advantages: Advantages: The ability to carry much more information and deliver it with greater fidelity than either copper wire or coaxial cable. The ability to carry much more information and deliver it with greater fidelity than either copper wire or coaxial cable. Fiber optic cable can support much higher data rates, and at greater distances Fiber optic cable can support much higher data rates, and at greater distances The fiber is totally immune to virtually all kinds of interference, including lightning, and will not conduct electricity. It can therefore come in direct contact with high voltage electrical equipment and power lines. The fiber is totally immune to virtually all kinds of interference, including lightning, and will not conduct electricity. It can therefore come in direct contact with high voltage electrical equipment and power lines. POWERGRID uses overhead fiber optic communication: POWERGRID uses overhead fiber optic communication: OPGW (optical ground wire cable) OPGW (optical ground wire cable)OPGW ADSS (all dielectric self supporting cable) ADSS (all dielectric self supporting cable)ADSS WRAP AROUND WRAP AROUNDWRAP AROUNDWRAP AROUND

33. Fibre Optic Systems

34. OPGW FODP OLTE ADD DROP MUX 2 MB/S MICROWAVE RADIO TERMINAL 2 MB/S INTEGRATION OF DIGITAL & ANALOG NETWORKS PLCC VOICE CARD DATA CARD

35. OPGW OPGW (optical ground wire) replaces shield wires OPGW (optical ground wire) replaces shield wires Provides lightning protection Provides lightning protection Provides communication Provides communication Lightning short circuit damage Lightning short circuit damage Installation requires long term outage Installation requires long term outage Expensive Expensive Superior performance Superior performance

36. ADSS F.O ADSS (all dielectric self supporting) which ADSS (all dielectric self supporting) which is mounted at various locations, typically 3 is mounted at various locations, typically 3 to 10 meters below the phase conductors. to 10 meters below the phase conductors. ADSS costs less than OPGW ADSS costs less than OPGW Higher fiber count than Wrap type. Higher fiber count than Wrap type. Can be installed on towers not designed for shield wires. Can be installed on towers not designed for shield wires. Suitable for hot line installation Suitable for hot line installation

37. WRAP AROUND F.O Wrap-type which is wound around shield wires and, in some instances, around energized conductors Wrap-type which is wound around shield wires and, in some instances, around energized conductors Hot-line installation is difficult Hot-line installation is difficult Cost more than ADSS, but less than OPGW Cost more than ADSS, but less than OPGW Need a shield wire Need a shield wire No operation problem is observed No operation problem is observed

38. OPGW WRAP ADSS OVERHEAD CABLES FOR POWER UTILITIES

40. FIBRE OPTIC CABLE INSTALLATION OPGW WRAP AROUND ADSS AD\AS\RKG\JP\FIBINST

41. SATELLITE COMMUNICATION A geostationary satellite is used as an active repeater. A geostationary satellite is used as an active repeater. Modulated signals are send from earth VSATs in 6 GHz band to the satellite. Modulated signals are send from earth VSATs in 6 GHz band to the satellite. Signals are beamed back to earth in 4 GHz band. Signals are beamed back to earth in 4 GHz band. Roundtime propagation delay of 540ms exists Roundtime propagation delay of 540ms exists Communication is interrupted during eclipses. Communication is interrupted during eclipses.

42. WHAT IS SCADA S upervisory C ontrol A nd D ata A cquisition is the system which enables us to S upervisory C ontrol A nd D ata A cquisition is the system which enables us to “ supervise, control, optimise and manage the Power Systems in an efficient manner to provide stable, secure and reliable power to the end consumer”.

43. FUNCTIONS OF SCADA DATA ACQUISITION DATA ACQUISITION PROCESSING OF ACQUIRED DATA. PROCESSING OF ACQUIRED DATA. LIMIT / STATUS MONITORING & ALARMING. LIMIT / STATUS MONITORING & ALARMING. NETWORK STATUS PROCESSOR. NETWORK STATUS PROCESSOR. SEQUENCE OF EVENT RECORDING. SEQUENCE OF EVENT RECORDING. INFORMATION STORAGE & RETRIEVAL. INFORMATION STORAGE & RETRIEVAL. DATA EXCHANGE DATA EXCHANGE SUPERVISORY CONTROL. SUPERVISORY CONTROL.

44. SCOPE FOR DATA-ACQUISITION UNDER ULDC SCHEMES in INDIA All generating stations of 50MW or All generating stations of 50MW or above(10 MW or above in case of NER) above(10 MW or above in case of NER) All 400 KV Sub-Stations. All 400 KV Sub-Stations. All 220 KV Sub-Stations. All 220 KV Sub-Stations. All 132 KV Sub-Stations operated where All 132 KV Sub-Stations operated where Inter-State lines are located. Inter-State lines are located. Important 66 KV Sub-Stations (NER only). Important 66 KV Sub-Stations (NER only).

45. Andhra Pradesh Karnataka Kerala Tamilnadu UT of Pondy Vijayawada Warangal HYDERABAD Ghanapur Chinkampalli CHENNAI Pondy Madurai Kannur-B KALAMASSERY Vydyuthi Bhavanam Erode MW Link FO Link State owneed Link Sub-LDC SLDC RCLDC Lingasugur Davangere Bangalore Information Flow to Control Centres Satellite Ramagundam

46. Lingasugur

47. Sembatti Madurai 400 Trichy 400 Paramakudi Samayapuram Madurai North Kodayar PH2 Madurai Sub LDC Karaikudi Tanjore 230 S R Pudur Pariyar PH Theni Kayathar E Sathur TTPS Podukotta C Echengodu Adanakottai Peramballur Kovilvenni Pugalur Thiruvarur Tuticorin Auto Trichy 230 Chennai Sub-LDC (NLC TS-I) Erode Sub-LDC (Erode) Wideband Channel Routing for Madurai Sub-LDC Orthonadu Sivagangai Existing RTU – 9 nos. Existing RTU integrated New RTUs – 13 nos. PLCC Link MW Link

48. ChalakudyT. NorthKozhikode -BKannur-B Kalamassery Pallom KayamkulamKundraParipallyTrivendrum North Vidyuthi Bhavanam RSCC,Bangalore (Udumalpet) Wideband Routing from Sub-LDC to SLDC,(Kalamassery) COMMUNICATION NETWORK FOR KERALA MW Link FO Link