Pre Commissioning for Switchyard Equipment

& PLCCBy

Md Maaz AlamEngineer(O & M) Ranchi

PLCC Commissioning

LINE TRAPSCOUPLING DEVICESCOUPLING CAPACITOR/ CAPACITOR VOLTAGE TRANSFORMER (CVT)COAXIAL CABLECARRIER TERMINALPOTECTION COUPLER

ELEMENTS OF PLCC SYSTEM

PLCC Commissioning

CARD USED IN BPL MAKE PLCC PANEL

1.95 SPIN( SPEECH INTERFACE)2.95 MODEM (MODULATION)3.95 DATA4.95 AMP (AMPLIFIER)5.95 PLF (PROGRAMMABLE LOW BAND

PASS FILTER)6.95 LINT (LINE INTERFACE)7.95 MEMRI (MEASURE & MONITOR

INDICATION)8.95 PWR INT

PLCC Commissioning

TRANSMISSION THROUGH PLCC PANELSPINDATA

MODEM AMPLIFIER PLF LINT

CO AXIALLMUCVTLINE

RECIEVING THROUGH PLCC PANEL

LINE CVT LMU CO AXIAL MODEM

SPINDATA

PLCC Commissioning

MODULES USED IN BPL MAKE PROTECTION COUPLER

1.67 PWR (POWER)2.67 OSC (OSCILLATOR)3.67 LOGIC I 4.67 REC (F1, F2, F3, F4, F5, F6)5.67 LOTS (LOOP TEST MODULE)6.67 INOP (INPUT OUTPUT

MODULE)7.67 TIME (TEST AND INTERFACE

MODULE)8.67 COUNT (COUNTER MODULE)

PLCC Commissioning

RETURN LOSS

COMPOSITE LOSS

END TO END SPEECH RESPONSE

TRIP TRANSMISSION TIME MEASUREMENT

END TO END TRIP COMMOND TRANSMISSION & RECEPTION

SNR TEST

PLCC Commissioning

C C

COMPOSITE LOSS ON LMU600 ohm

FEED 0 dB ,75 ohm AT BT I/P & MEASURE ACROSS THE 600 OHM RESISTOR WITH LEVEL METER IN HI OHMIC FOR VARIOUS FREQUENCIES FOR THE BANDWIDTH MENTIONED IN THE LMU.

THE LEVEL MEASURED SHOULD BE + 9 dB FOR IDEAL CONDITION. LEVEL LESS THAN -9 dB WILL BE CONSIDER AS LOSS IN THE LMU

PLCC Commissioning

COMPOSITE LOSS ON COAXIAL CABLE

FEED 0 dB 75 OHMS AT PLCC END AND MEASURE AT LMU END ACROSS 75 OHMS. THE LOSS WILL BE ABOUT 0.3 dB TO 0.7 dB FOR HALF KM

PLCC Commissioning

RETURN LOSS TEST

600 ohm

COAXIAL CABLE

ZX ZN SYM +10dB ,0 OHM

CC

OSC

FEEDING + 10dB , 0 ohm TO RETURN LOSS BOX , CONNECTING ‘BT’ I/P TO ZX OF THE BOX, CONNECTING 75 ohm TO ZN OF THE BOX. SWITCH PROVIDED IN THIS BOX SHOULD BE TOWARDS ‘Refl’ POSITION. CHORD PROVIDED IN THIS BOX SHOULD BE IN CONNECTED TO LEVEL METER.

LEVEL METER SHOULD MEASURE -12 dB FOR IDEAL CONDITION. THIS LEVEL CAN GO AS LOW AS POSSIBLE BUT ON THE HIGHER SIDE THE LEVEL SHOULD NOT GO ABOVE -10 dB

SPEECH RESPONSE TEST

FEED -3.5 dB ,600 OHMS AT P1,P2 FOR VARIOUS FREQUENCIES, IN THE BANDWIDTH 300 HZ TO 2400 AT ONE END IN THE OTHER END MEASURE AT P3,P4 LEVEL METER TERMINATED WITH 600 OHMS J35 JUMPER IN 95 MOTHER BOARD IN ‘A’ POSITION

FOR LEVEL OBTAINED AT 800 HZ SHOULD BE CONSIDERED AS REFERNCE LEVEL AND FOR THE OTHER FREQUENCIES THE LEVEL SHOULD BE WITHIN +1dB /-3dB OF REFERENCE

PLCC Commissioning

SIGNAL TO NOISE RATIO TESTSIGNAL TO NOISE RATIO = LEVEL RECEIVED WITH SIGNAL /

LEVELS RECEIVED WITHOUT SIGNAL

1. FEED -20 dB ,600 OHMS 2 KHZ AT P30/ GND IN STATION A2. AT STATION B MEASURE AT CO-AXIAL (HF+2 KHz) WITH HI OHMIC3. STOP FEEDING THE LEVEL AT STATION- A AND MEASURE (HF + 2 KHz) AT STATION – B IN CO-AXIAL SNR= LEVEL MEASURED AT STEP 2/LEVEL MEASURED AT STEP 3

SNR IN DATA/PROTECTION PANEL

4. FEED -20 dB ,600 OHMS 2 KHZ AT P30/ GND IN STATION A5. AT STATION B MEASURE AT P22/23 WITH J15,J16 & J17 OF MB IN ‘A’ POSITION (2KHz , ACROSS 600 OHMS6 STOP FEEDING THE LEVEL AT STATION- A AND MEASURE ( 2 KHz) AT STATION – B IN WITH J15 OF 95 MB IN ‘A’ POSITION SNR= LEVEL MEASURED AT STEP 2/ LEVEL MEASURED AT STEP 3

PLCC Commissioning

CIRCUIT BREAKER

1. DYNAMIC CURRENT RESISTANCE MEASUREMENT2. CONTACT RESISTANCE MEASUREMENT

3. TRIPPING AND CLOSING TIME

4. CAPACITANCE AND TAN DELTA MEASUREMENT

5. TRIPPING AND CLOSING COIL RESISTANCE MEASUREMENT

6. OPERATIONAL LOCKOUT CHECKING

7. POLE DISCREPANCY RELAY TESTING

6 DEW POINT & LEAKAGE TEST OF SF6

PRECOMMISSIONING TEST OF CIRCUIT BREAKER

CURRENT TRANSFORMER

PRECOMMISSIONING TEST OF CURRENT TRANSFORMER1.SECONDRY WINDING RESISTANCE OF ALL THE CORE

WINDING

2. POLARITY TEST (WITH 1.5 VOLT DC SUPPLY , CONNECT +VE AT P1 AND –VE AT P2)

3.TAN DELTA AND CAPACITANCE MEASUREMENT

4.CURRENT RATIO TEST , PRIMARY INJECTION THROUGH PRIMARY INJECTION KIT AT PRIMARY TERMINAL P1-P2 MEASURE CURRENT ON THE SECONDARY TERMINALS

5.MAGNETISING CURVES PERFORMANCE , KNEE POINT VOLTAGE

6.CONTACT RESISTANCE MEASUREMENT

CURRENT TRANSFORMER

MEASURING MAGNETIZING CURRENT CHARACTERISTIC

V

A

0-5 KV

0-500 mA APPLIED VOLTAGE IS INCREASED FROM ZERO TO RATED KNEE POINT VOLTAGE IN STEPS OF 25%, 50%, 75%, 100% & 110%. MEASURE THE CURRENT DRAWN BY THE CT SECONDARY CORE AT RESPECTIVE APPLIED VOLTAGE.

KNEE POINT VOLTAGE IS NORMALLY DEFINED AS THE VOLTAGE AT WHICH 10% INCREASE IN THE APPLIED VOLTAGE CAUSES 30 TO 50% INCREASE IN SECONDRY CURRENT.

V

CAPACITOR VOLTAGE TRANSFORMER

1.SECONDARY WINDING RESISTANCE

2.VOLTAGE RATIO TEST

3.CONTINUITY TEST OF THE WINDING

4.IR BETWEEN PRIMARY TO SECONDARY CORE , CORE TO CORE & CORE TO EARTH

5.TAN DELTA AND CAPACITANCE MEASUREMENT ACROSS STACK

TRANSFORMER

PRECOMMISSIONING TEST FOR TRANSFORMER1.INSULATION RESISTANCE

MEASUREMENT2.MEASUREMENT OF WINDING

RESISTANCE3.MAGNETIC BALANCE TEST4.FLOATING NEUTRAL VOLTAGE

MAESUREMENT5.VOLTAGE RATIO TEST6.CORE INSULATION TEST7.MAGNETISATION CURRENT TEST8.VECTOR GROUP TEST & POLARITY

CHECKING9.INSULATION RESISTANCE

MEASUREMENT OF BUSHING CTs10.SHORT CIRCUIT IMPEDENCE TEST11. FREQUENCY RESPONSE ANALYSIS

TEST12.TAN DELTA AND CAPAACITANCE

MEASUREMENT OF WINDINGS & BUSHING

13.PROTECTION AND ALARM TEST

1.INSULATION RESISTANCE MEASUREMENTHV + IV TO LV

HV + IV TO ELV TO E

MINIMUM DESIRED IR VALUE AT 1 MIN 400 KV ICT IS 500 MEGA OHM POLARIZATION INDEX = R10 / R1

2. MEASUREMENT OF WINDING RESISTANCEFOR STAR CONNECTED AUTO-TRANSFORMER THE RESISTANCE OF THE HV SIDE IS MEASURED BETWEEN HV TERMINAL AND IV TERMINAL, THEN BETWEEN IV TERMINAL AND THE NEUTRAL AT ALL TAPS

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3. MAGNETIC BALANCE TESTAPPLY SINGLE PHASE 230 V ACROSS ONE PHASE OF HV WINDING & NEUTRAL THEN MEASURE VOLTAGE IN OTHER YWO HV TERMINALS ACROSS NEUTRAL. REPEAT TEST FOR EACH OF THE THREE PHASES & IV WINDING ALSO.

THE VOLTAGE INDUCED IN THE CENTER PHASE SHALL BE 50 TO 90% OF THE APPLIED VOLTAGE. WHEN THE CENER PHASE IS EXITED THEN VOLTAGE INDUCED IN THE OUTER PHASES SHALL BE 30 TO 70% OF THE APPLIED VOLTAGE 4. FLOATING NEUTRAL VOLTAGE MAESUREMENTAPPLYING 3 PHASE 415 VOLT SUPPLY ACROSS HV WINDING OR IV WINDING (DISCONNECTING NEUTAL FROM THE GROUND). FOR HEALTHY TRANSFORMER , WHEN 3 PHASE BALANCE VOLTAGE IS APPLIED , THE VOLTAGE BETWEEN NEUTRAL & GROUND IS ZERO OR NEGLIGIBLE VOLTAGE

REACTOR

PRECOMMISSIONING TEST OF REACTOR1.INSULATION RESISTANCE

MEASUREMENT2.WINDING RESISTANCE MAESUREMENT3.MAGNETIZING CURRENT TEST4.STABILITY TEST OF DIFFERENTIAL &

REF PROTECTION5.CONTACT RESISTANCE MEASUREMENT6.TAN DELTA AND CAPACITANCE

MEASUREMENT OF BUSHING & WINDING

7.PROTECTION AND ALARM TEST8.FREQUENCY RESPONSE ANALYSIS

ISOLATOR AND EARTH SWITCH

1.INSULATION RESISTANCE VALUE OF MOTOR WINDING

2.OPERATIONAL MOTOR CURRENT

3.MEASUREMENT OF OPENING & CLOSING TIME

4.PICK UP & DROP UP VOLTAGE OF CLOSING, OPENING & INTERLOCK COIL

5.CONTACT RESISTANCE MEASUREMENT