DC FAILURE 4X110 MW NTPC TANDA

RAVI PAL SINGH OPERATIONS MAIN PLANT GROUP-C

LAYOUT

•ELECTRICAL SYSTEMS

•DVR SUPPLY CIRCUITS

•C&I SYSTEMS

•BOILER TRIP

•TURBINE TRIP

•ACTIONS TO BE TAKEN

•HEALTHINESS OF DC SYSTEM

ELECTRICAL

SYSTEMS

LT SW GR MCC

• LOSS OF 220V DC FOLLOWING WILL RETAIN

THEIR POSITIONS AND BECOME

INOPERATIVE:

– INCOMER BREAKER

– TIE BREAKER

– BUS COUPLER

• HENCE THESE BREAKER NEED TO BE

CLOSED/OPENED MANUALLY FROM PANEL

• CONTROL/PROTECTION OF DRIVES PANEL

BY 230 V AC/110 V AC. HENCE IN CASE OF

220 V DC FAILIURE THESE WILL BE NORMAL.

HT SW GR MCC

• LOSS OF 220 V DC FOLLOWING

WILL RETAIN THEIR POSITIONS

AND BECOME INOPERATIVE:

– INCOMER BREAKER

– TIE BREAKER

– BUS COUPLER

– DRIVE MODULE BREAKERS

GRP: GENERATOR RELAY

PANEL

• LOSS OF 220 V DC:

– MAIN TRIPPING RELAYS WILL CONTINUE TO REMAIN IN THEIR POSITIONS.

– NO PROTECTIONS AND TRIPPING OF GENERATOR WILL OPERATE.

– ALARM SYSTEM OF UNIT#3 ONLY (GENERATOR PANELS) WILL BE LOST.(UNIT#1, 2 AND 4 ALARM PANEL IS THROUGH 24 V DC).

DVR SUPPLY CIRCUITS

AC/DC CONVERTOR

220 V DC SELECTORS

DVR

220 V DC

3 ɸ AC

DVR SUPPLY CIRCUITS CONTD...

AC/DC CONVERTOR

220 V DC SELECTORS

DVR

220 V DC

3 ɸ AC

DVR: DIGITAL VOLTAGE

REGULATOR

• LOSS OF 220 V DC WILL CAUSE

NO AFFECT ON PROTECTION

AND OPERATION CONTROL OF

DVR.

C&I

SYSTEMS

BOILER TRIP

FSSS MFT

ALL PULVERISERS TRIP

ALL FEEDERS TRIP

ALL HAGs CLOSE

HOTV CLOSE

ALL HONVs CLOSE

ALL PA FANS TRIP

TURBINE STOP VALVES CLOSE

24 V DC

TURBINE TRIP

TIP (220 V DC)

SKODA SYSTEM (24 V DC)

TTR 1 TTR 2

220 V DC

230 V AC

TTS 1

TTS 2

TTS 3

24 V DC CONVERTOR AND MAX SELECTOR

MFT GENERATOR

BREAKER OPEN

TURBINE STOP VALVES CLOSE

TTR 1/2 (220 V DC) :ENERGISE TO TRIP TTS 2/3 (24 V DC) :DE ENERGISE TO TRIP

TURBINE TRIP CONT...

• TIP TURBINE PROTECTIONS:

– CONDENSOR VACUUM VERY LOW

– LUBE OIL PRESSURE VERY LOW

– HRH TEMPERATURE VERY LOW

– AXIAL SHIFT VERY HIGH

– MAIN OIL PRESS VERY LOW

– MOP DISCHARGE PRESSURE VERY LOW

– HP AND MP CASING DIFF TEMP VERY HIGH

– GENERATOR TRIP TO TURBINE TRIP

– BOILER TRIP TO TURBINE TRIP

• SKODA SYSTEM TURBINE PROTECTIONS:

– OVERSPEED

– TRIP OIL LOSS

220 V DC LOST AND 24 V DC

AVAILABLE • FSSS:

– MFT WILL OPERATE AND FOLLOWING INTERLOCKS WILL

INITIATE:

• ALL PULVERISERS TRIP

• ALL FEEDERS TRIP

• ALL HAGS CLOSE

• HOTV CLOSE

• ALL HONVS CLOSE

• ALL PA FANS TRIP

– TRIP DUE TO LOSS OF 220 V DC ALARM WILL APPEAR.

– HOTV WILL CLOSE (220 V DC DEENERGISE TO CLOSE).

– ALL FEEDERS WILL TRIP.

– HAGS WILL CLOSE.

– HONVS WILL CLOSE.

– BOILER TO TURBINE TRIP WILL INITIATE.

– PULVERISERS WILL NOT TRIP

– PA FANS WILL NOT TRIP

220 V DC LOST AND 24 V DC

AVAILABLE CONT... • TIP AND SKODA SYSTEM:

– TIP TURBINE PROTECTIONS WILL BECOME

UNAVAILABLE

– SKODA SYSTEM TURBINE PROTECTIONS WILL BE

AVAILABLE

– IN CASE OF TURBINE TRIP BY SKODA SYSTEM

PROTECTIONS TURBINE WILL TRIP BUT TTR WILL NOT

OPERATE AND HENCE GENERATOR TRIP COMMAND

WILL NOT BE INITIATED.

– TIP SYSTEM SUPPLY FAIL ALARM WILL APPEAR

– AC EOP WILL BECOME ON.

– TTR WILL NOT OPERATE AT BOILER TO TURBINE TRIP

TURBINE STOP VALVES WILL NOT CLOSE.

GENERATOR WILL NOT TRIP.

220 V DC AVAILABLE AND 230 V AC

(FOR 24 V DC SKODA SYSTEM) LOST • FSS:

– MFT AT ALL ELEVATION SCANNER SUPPLY LOSS AND FOLLOWING

INTERLOCKS WILL INITIATE

• ALL PULVERISERS TRIP

• ALL FEEDERS TRIP

• ALL HAGs CLOSE

• HOTV CLOSE

• ALL HONVs CLOSE

• ALL PA FANS TRIP

– ALL ABOVE MENTIONED PROTECTIONS WILL OPERATE.

– BOILER TO TURBIN TRIP WILL INITIATE.

• TIP AND SKODA SYSTEM:

– ALL TIP AND SKODA SYSTEM TURBINE PROTECTIONS WILL BE

AVAILABLE.

– TTR WILL OPERATE AT BOILER TO TURBIN TRIP PROTECTION.

– GENERATOR TRIP COMMAND WILL INITIATE.

– ALL MAX AND OVATION WORKSTATIONS WILL SWITCH OFF (AT 230 V

AC LOSS). TURBINE STOP VALVES WILL CLOSE.

GENERATOR WILL TRIP.

220 V DC LOST AND

24 V DC LOST • FSSS:

– HOTV WILL CLOSE AT LOSS OF 220 V DC

– FEEDER MOTORS WILL TRIP.

– HAGS WILL NOT CLOSE.

– HONVS WILL NOT CLOSE. (EXCEPT FOR ELEV GA AND

EF)

– PULVERISERS WILL NOT TRIP

– PA FANS WILL NOT TRIP

– BOILER TO TURBINE TRIP WILL NOT INITIATE.

220 V DC LOST AND

24 V DC LOST CONTD... • TIP AND SKODA SYSTEM:

– TIP TURBINE PROTECTIONS WILL BECOME

UNAVAILABLE

– SKODA SYSTEM TURBINE PROTECTIONS WILL BE

AVAILABLE

– TURBINE WILL ONLY TRIP IF ANY SKODA SYSTEM

PROTECTIONS ACTS.

– AC EOP WILL BECOME ON.

– TTR WILL NOT OPERATE

– ALL MAX & OVATION WORKSTATIONS WILL BE RUNNING

BUT NO MONITORING AND CONTROL WILL BE

AVAILABLE.

– TIP SYSTEM SUPPLY FAIL ALARM WILL NOT APPEAR

TURBINE STOP VALVES WILL NOT CLOSE.

GENERATOR WILL NOT TRIP.

220 V DC LOST, 24 V DC LOST AND 230 V AC LOST (FOR 24 V DC TO SKODA SYSTEM) • FSSS:

– HOTV WILL CLOSE AT LOSS OF 220 V DC

– FEEDER MOTORS WILL TRIP

– HAGS WILL NOT CLOSE.

– HONVS WILL NOT CLOSE.(EXCEPT FOR ELEV GA AND

EF)

– PULVERISERS WILL NOT TRIP

– PA FANS WILL NOT TRIP

– BOILER TO TURBIN TRIP WILL NOT INITIATE.

220 V DC LOST, 24 V DC LOST AND 230 V AC LOST (24 V DC TO SKODA SYSTEM) CONTD...

• TIP AND SKODA SYSTEM:

– TTS WILL OPERATE AT LOSS OF 24V DC (BOTH

SUPPLIES).

– AC EOP WILL BECOME ON.

– TTR WILL NOT OPERATE.

– TIP SYSTEM SUPPLY FAIL ALARM WILL NOT APPEAR.

– ALL MAX AND OVATION WORKSTATIONS WILL SWITCH

OFF (AT 230 V AC LOSS).

TURBINE STOP VALVES WILL CLOSE.

GENERATOR WILL NOT TRIP.

ELECTROMAGNETIC

RELAY PANEL

• LOSS OF 220 V DC

– NRV WILL REMAIN INOPERATIVE

– TO BE CLOSED BY ISOLATING AIR SUPPLY

MANUALLY.

ACTIONS TO BE TAKEN

• IMMEDIATELY INFORM TO HOD (OPERATION), HOD

(EMD) & OTHER EMD PERSONALS ABOUT DC

FAILURE.

• PERFORM THE UNDER MENTIONED ACTIVITIES :

– TRIP TURBINE FROM FRONT PEDASTAL EPB, TO

CLOSE THE STOP VALVES.

– TRIP PULVERISERS AND PA FANS MANUALLY

FROM SW GR PANEL EPB.

– TAKE THIS UNIT ON 220KV TRANSFER BUS.

– TRIP THE BUS COUPLER BREAKER FROM MCB

CONTROL PANEL.

– GENERATOR WILL TRIP.

• IN CASE OF S/Y 220 V DC FAILURE TRIP S/Y

BREAKER BY MANUAL EPB PRESENT NEAR THE

BASE OF Y-PHASE BREAKER IN SWITCH YARD.

HEALTHINESS OF DC SYSTEM

OK DCDB

DC EOP STARTER PANEL

DC EOP EPB

DC EOP CONTROL SUPPLY

OVERLOAD RELAY OF DC EOP

HEALTHINESS OF DC SYSTEM

NOT OK DCDB

DC EOP STARTER PANEL

DC EOP EPB

DC EOP CONTROL SUPPLY

OVERLOAD RELAY OF DC EOP

VIJAY VERMA

ALEKH SINHA

ABHISHEK CHAUHAN

ASHOK KUMAR YADAV

ANIL KUMAR SRIVASTAVA

ASHISH TRIPATHI

KAMAL SHANKAR UPADHYAY

VISHNU PRATAP SINGH

PRADEEP ARYA

AWN HAIDER RIZVI

MAYANK JAIN

ANKIT KUMAR

SANJEEV KUMAR SINGH

SHYAM SUNDER RAM

SPECIAL THANKS TO

THANK YOU