The document discusses various aspects of power system protection. It describes different types of electrical faults that can occur, such as phase-to-phase short circuits and phase-to-ground faults. The key tasks of a protection system are to protect electrical equipment from unnecessary damage, protect personnel near faults, and enable continued service in unaffected areas. Protection schemes aim to operate abnormally but securely, maintaining normal operation until a fault occurs. Requirements for protection systems include speed, selectivity, sensitivity, reliability and simplicity. The document outlines protection schemes and relay logic for generators, transformers, feeders and busbars.

1. PROTECTION OF POWER SYSTEM PREPARED BY TRAINEE ENGINEER MUDDASIR MASOOD

2. WHAT DOES PROTECTION MEANS EVERY THING IN THIS WORLD NEEDS PROTECTION AGAINST THREATS SO DOES ELECTRICAL EQUIPMENTS INTERNAL THREATS EXTERNAL THREATS DAMAGED POWER SYSTEM CRITICAL ELECTRICAL EQUIPMENT

3. TYPES OF ELECTRICAL THREATS/FAULTS PHASE TO PHASE SHORT CIRCUIT PHASE TO GROUND FAULT SHUNT FAULTS SERIES FAULT OPEN CIRCUIT

4. TASK OF THE PROTECTION SYSTEM PROTECT THE ELECTRICAL EQUIPMENT AGAINST UNESISSARY DAMAGE PROTECT THE PERSONAL IN THE VICINITY OF THE ELECTRICAL FAULT ENABLE CONTINUED SERVICE IN THE UNTROUBLED AREA OF THE NETWORK

5. PHILOSPHY OF THE PROTECTION SYSTEM ABNORMAL BUT SECURE OPERATION NORMAL NETWORK OPERATION FAULT CONDITION ABNORMAL NETWORK OPERATION

6. REQUIREMENT OF THE PROTECTION SYSTEM SPEEDY SELECTIVITY SENSITIVITY RELIABILITY SIMPLICITY

7. PROTECTION SCHEME FOR THE POWER SYSTEM PROTECTION SYSTEM IS DIVIDED INTO ZONES PROTECTION ZONES ARE DECIDED BY THE LOCATION OF CT PRIMARY PROTECTION BACKUP PROTECTION EARTH FAULT PROTECTION DIFFERENTIAL PROTECTION GT-1 CIRCUIT BREAKER POWER TRANSFORMER GENERATOR CURRENT TRANSFORMER 132KV BUSBAR

8. TYPICAL PROTECTION SCHEME TRIP COIL-1 TRIPPING MECHANISM TRIP COIL-2 DC SUPPLY TRIP CIRCUIT PROTECTION RELAY-1 DC SUPPLY TRIPING MATRIX PROTECTION RELAY-2

9. BREAKER FAILURE SCHEME INTEGRATED POWER SYSTEM G PROTECTIVE RELAY TRIP ALL PARALLEL CB M BREAKER FAILURE TIME DELAY

10. TYPE OF EARTHING SYSTEM LITTLE FAULT CURRENT EXTREME OVERVOLTAGE UNEARTHED NEUTRAL LARGE FAULT CURRENT NO OVERVOLTAGE DIRECTLY EARTHED LESS FAULT CURRENT LESS OVERVOLTAGE INDUCTOR/ TRANSFORMER GROUNDING

11. GENERATOR PROTECTION VOLTAGE RISE PROTECTION ROTOR EARTH FAULT PROTECTION DIFFERENTIAL PROTECTION IMPEDENCE PROTECTION G UNDEREXCITATION PROTECTION REVERSE POWER PROTECTION NEGATIVE PHASE SEQUENCE PROTECTION 80% STATOR EARTH FAULT R 100% STATOR EARTH FAULT

12. UNIT STEPUP TRANSFORMER PROTECTION UNIT TRANSFORMER BUCHHOLZ TRIP PRESSURE RELIEF OLTC TRIP Y OIL TEMPERATURE TRIP Y BAT ∆ ∆ TRANSFORMER EARTH FAULT PROTECTION WINDING TEMPERATURE TRIP GENERATORTRANSFORMER DIFFERENTIAL PROTECTION POWER TRANSFORMER OTHER PROTECTIONS ∆ G Y BBT Y Y R

13. PROTECTION LOGIC ADOPTED AT BLOCK-1 TWO INDEPENDANT TRIP COILS TRIP SUPERVISORY CKT 220 OR 24 VOLT POWER SUPPLY TRIPPING MATRIX +24 PROTECTION RELAY TRIP CIRCUIT TRIP RELAY OPENING MECHANISM OF CB TRIP CIRCUIT SUPERVISION TRIP ANNUNCIATION TRIP COMMAND REGISTER

14. TRIPPING MATRIX OVERCURRENT TIME PROTECTION EXCT. TRAFO UNDER EXCITATION PROTECTION WITH 2 STEP UNIT AUXILIARY TRANSFORMER DIFFERENTIAL PROTECTION LOSS OF EXCITATION PROTECTION UNIT TRANSFORMER BUCHOLZ OVERTEMP. 100% EARTH FAULT PROTECTION UNDEREXCITATION PROTECTION UNBALANCED LOAD PROTECTION REVERSE POWER PROTECTION WITH TIME DELAY EXCITATION TRANSFORMER BUCHOLZ TRIP FREQUENCY DROP PROTECTION SS TRANSFORMER BUCHOLZ OVERTEMP. OVERFLUXING PROTECTION IMPEDENCE PROTECTION T1 IMPEDENCE PROTECTION TE UNIT TRANSFORMER DIFFERENTIAL PROTECTION TRANSFORMER EARTH FAULT PROTECTION SS TRAFO OVERCURRENT TIME PROTECTION ROTOR EARTH FAULT PROTECTION 80% EARTH FAULT PROTECTION FREQUENCY RISE GENERATOR DIFFERENTIAL PROTECTION SFC EARTH FAULT REVERSE POWER PROTECTION VOLTAGE RISE PROTECTION SFC FAILURE SYNC BREAKER-1 SYNC BREAKER-2 ST SERVICE SUPPLY BREAKER EMERGENCY TRIP DE-EXCITATION SFC BREAKER EXCIT. BREAKER UNIT AUXILIARY CHANGEOVER LOCAL INDICATION REMOTE SIGNAL RESET

15. POWER SUPPLY CIRCUIT BREAKER TRIP COILS L+ 220V L-

16. GENERATOR DIFFERENTIAL PROTECTION 7TD43 G IS=I1=I2 IA=0 NO TRIPPING I1 RACTIFIER IA TRIPPING TRANSFORMER RACTIFIER IS I2 STABILIZING TRANSFORMER TM SYNCH BREAKER-1 DE-EXCITATION BREAKER SFC BREAKER UNIT AUX CHANGOVER ST SERVICE SUPPLY BREAKER EMERGENCY TRIP SYNCH BREAKER-2

17. GENERATOR DIFFERENTIAL PROTECTION PROTECTION AGAINST PHASE TO PHASE FAULT PROTECTION AGAINST PHASE TO EARTH FAULT PROTECTION ZONE DEFINED BY THE LOCATION OF CTS INSENSITIVE TO INTERTURN FAULTS INOPERATIVE TO EXTERNAL FAULTS EARTH FAULT SENSITIVITY DEPEND UPON GROUNDING SYSTEM

18. GENERATOR DIFFERENTIAL PROTECTION BLOCK Us/Un TRIP Ua/Un PICKUP CHARACTERISTIC FOR THE SINGLE INFEED FAULT

19. 100% EARTH FAULT PROTECTION 7ue21 20 HZ FREQUENCY GENERATOR CT SYNCH BREAKER TRIP MATRIX DE-EXCITATION RACTIFIER SERVICE STATION TRIP EMERGENCY TRIP MEASURING CURRENT Im COMPARATOR COMPENSATING CURRENTIc SFC LIMIT VALUE SETTER AUXILLARY CHANGEOVER IC>Im TIMMER TRIP SIGNAL

20. 100% EARTH FAULT PROTECTION EARTH FAUTL DUE TO INSULATION DAMAGE SHORT CIRCUIT DUE TO THE PHASE WITH THE CORE EARTH FAULT PROTECTION HIGHLY SENSITIVE DETECTION OF THE EARTH FAULT AT ANY LOCATION

21. 80% EARTH FAULT PROTECTION VOLTAGE INPUT MODULE 7TM36 VOLTAGE TRIGGER MODULE 7TU12 PICKUP TIMMER 7TT10 TRIP

22. ROTOR EARTH FAULT PROTECTION 7UR20 UNGROUNDED FIELD WINDING SINGLE EARTH FAULT CAUSE LITTLE CURRENT DOUBLE EARTH FAULT/ MAGNETIC UNBALANCE HIGH CURRENT AT THE FAULT LOCATION ELECTRICAL STRESS INCREASES EXCITATION SYSTEM IE

23. ROTOR EARTH FAULT CONT. DETECT BEFORE IT EFFECTS COUPLING RESISTER Rv SET VALUE Re Rc LOW PASS FILTER WAIT FOR THE STEADY STATE LIMIT VALUE GENERATOR SQUARE WAVE Rm UM ALARM <80KΩ TRIPPING <5KΩ SYNCH BREAKER-1 AND 2 DE-EXCITATION BREAKER SERVICE STATION BREAKER EMERGENCY TRIP SFC AUXILLIARY CHANGEOVER TRIPPING SIGNAL TRIPPING MATRIX

24. UNDEREXCITATION PROTECTION CAUSE HIGHLY CAPACITIVE LOAD TOO LOW EXCITATION/FIELD CIRCUIT FAULT EFFECT ROTOR OVERHEATING ASYNCHRONOUS OPERATION STEADY STATE STABILITY OF THE GENERATOR

25. UNDER-EXCITATION PROTECTION

26. UNDER-EXCITATION PROTECTION CURRENT INPUT 7TM16 TRANSDUCER 7TL41 T3 ANGLE TRIGGER(A) TRIP T2 TRIP ANGLE TRIGGER (C) VOLTAGE INPUT 7TM36 AC VOLTAGE MONITOR 7TU12 7TU14 EXCITER VOLTAGE MONITOR T1 TRIP ANGLE TRIGGER (B) SYNCH BREAKER-1 SYNCH BREAKER-2 DE-EXCITATION EMERGENCY TRIP SERIVCE STATION AUXILLIARY CHANGEOVER

27. NEGATIVE PHASE SEQUENCE PROTECTION CAUSE a ZERO SEQUENCE b c UNEVEN LOAD SERIES FAULT SHUNT FAULT POSITIVE SEQUENCE EFFECT ROTOR OVERHEATING ROTOR DISTORTION NEGATIVE SEQUENCE HEAVY VIBRATION

28. NEGATIVE PHASE SEQUENCE PROTECTION POWER SUPPLY 15V 2-17.5% 8-70% 2*(0.1-6.4) CURRENT INPUT MODULE 7TM16 LIMIT VALUE TRIGGER 7TP12 SEQUENCE FILTER 7TF20 TIMER 7TT11 TRIP THERMAL REPLICA/ INVERSE TIME CHARACTERISTIC TRIP UNBALANCE LOAD MONITORING TRIP TRIPPING MATRIX SYNCH BREAKER-1 AND 2

29. REVERSE POWER PROTECTION CAUSE FAILURE OF DRIVING TURBINE MOTORING OF GENERATOR EFFFECT COMPRESSOR LOAD SYSTEM OVERLOADED STEAM TURBINE BLADE OVERHEATING

30. REVERSE POWER PROTECTION/ DIRECTIONAL POWER RELAY CURRENT INPUT MODULE 7TM17 VOLTAGE INPUT MODULE 7TM37 POWER TRIGGER 7TM28 TRIP COUPLING MODULE 7TR20 TIMER 7TT11 TRIP TRIPPING MATRIX SYNCH BREAKER 1-2 TRIP T1 SERVICE STATION BREAKER DE-EXCITATION TRIP WITH LONG TIME UNIT AUXILLIARY CHANGEOVER

31. Frequency protection CAUSE OVER LOAD SYSTEM (UNDER FREQUENCY) LOAD SHEDDING (OVER FREQUENCY) FAULTY FREQUENCY RAGULATOR EFFECT GENERATOR/TRANSFORMER OVERHEATING

32. BUSBAR PROTECTION SCHEME IT IS IMPORTANT AT FIRST TO HAVE A KNOW HOW OF BUSBAR ARRANGMENT

33. BUSBAR PROTECTION HERE ARE SOME OF THE PROTECTION ADOPTED AT OUR SWITCHYARD TIME OVERCURRENT AND EARTH FAULT PROTECTION (IKT943) STATIC BUSBAR PROTECTION (INX5) STATIC DISTANCE RELAY (LZ92) FOR THE PROTECTION OF STEPUP TRANSFORMER, STARTUP TRANSFORMER AND AUTO TRANSFORMER ELECTROMECHANICAL DISTANCE RELAY (LH1) OVERCURRENT/UNDERVOLTAGE (IUX159) DIRECTIONAL EARTH FAULT (RE91-10)

34. PROTECTION LAYOUT OF THE FEEDERSIDE FEEDER DISTANCE PROTECTION(LZ92) DISTANCE RELAY(LH1) BUSBAR PROTECTION(INX5) DIRECTIONAL EARTH FAULT(RE91-10) MEASUREMENT OVERCURRENT/UNDERVOLTAGE(IUX159) BUSBAR B BUSBAR A

35. DISTANCE PROTECTION(LZ92) CAUSE OVERHEAD LINES SERIES/SHUNT FAULT EXTERNAL THREAT TO THE POWER UNIT EFFECT SUSEPTEBLE TO HIGH SHORT CIRCUIT CURRENT OUT OF STABILITY IMPLEMENTATION MEASURE THE IMPEDENCE OF THE FEEDING END ZONE DEFINED

36. TRANSMISSION LINE LINE IMPEDENCE LOAD DISTANCE RELAY(Zl) G SOURCE IMPEDENCE Zs FAULT IMPEDENCE Zf Uref SELECTION CIRCUIT CONSTANT TIME CURVE V TRIP AND RESISTANCE Uf I REACTANCE If I>/Z< TIMER

37. LINE CB TRIP COIL 1-2 AUTO RECLOSURE DISTANCE RELAY F11 TRIP SUPERVISION 1-2 CONSTANT CURRENT CHARACTERISTIC

38. THE END GOD BLESS U ALL