Equipement Cost reduction due to Reclamation work

Electrical Date : 26.11.2014

S.NO Spare Description Serviced by

Electronics cards

1 IGBT Power Module 527780 5 Nos 25000 M/s.Jerly Electronics 125000 2638900

2 Rectifier Module 156994 2 Nos 15000 OEG -HO 30000 313988

3 VFD Panel Exhaust Fan 4500 15 800 Tuticorin 12000 67500

Motor

1 109920 2 Nos 10000 Material procured by OEG 20000 109920

2 150000 1 No 8000 Jaya Engineering 8000 150000

3 39000001 No 29175 Coral rewinding works

99872 3900000

Rotor testing 1 No 70697 Coral rewinding works

4

DC System

112V Battery - Inside Plate damag 16000 5 Nos 1000 Everest Battery 5000 80000

2 Self Motor Service -Solinoid switch 25000 4 Nos 2500 Kumar AutoElectrical 10000 100000

Power cable

1 600 /Mtr 14 Nos 3100 43400 1500975

Cost of New equipement

Total No. Serviced

Cost of Service Total service

Cost Total cost of

Original equipement

BC-5 Motor - End Cover damaged

PA Fan -750KW End cover damaged

PA Fan -Rotor shaft pend rectification work

Motor coil rewinding work 0.25KW Motor to 180KW Motor

Depends upon the Capacity of Motor -Coil rewinding was done and Made ready to operate for Plant smooth running condition - Mani Electriccal -Tuticorin

300 sq.mm Power cable - damaged area cable joint Provided in 2500 Mtr

Material procured by OEG & Joint Provided by Ele Dept

2 498 /Mtr 3 Nos 2950 8850 298800240 sq.mm Power cable - damaged area cable joint Provided-600 Mtr

Material procured by OEG & Joint Provided by Ele Dept

Equipement Cost reduction due to Reclamation work

Date : 26.11.2014

Cost saving

Electronics cards

2513900

283988

55500

Motor

89920

142000

3800128

300000

DC System

75000

90000

Power cable

1457575

289950

Electrical Dept improvement works

S.NO JOB Done

1

2 UPS & Battery charger supply modification

3 Coal feeder tripping problem was rectified

4 CHP LDB shifting

5 Startup booster fan Local start/stop modification

6 MLDB Auto change over wiring

7 UPS, Non UPS supply modification to avoid any one

8 MCB provision for TVM

9 Unit-3 UAT charging

10 Boiler Feed water Pump motor-3A

11 All three units CEP motors, Crusher motors

12 Feedback wiring modification in CCW

Instrument air compressors Power supply modifications.

13 ESP transformer

14 Lighting transformer

15 All units Turbine AC Emergency Oil Pump

16 VFD Room Temperature

17 Phase shifting 3A breather

18

19 Power supply arrangement for Moisture separator

20 AVR ‘trip’ indication for unit 3 AVR panel.

21 Unit wise 1ph and 3ph supply

22 U# 3 generator DE bearing temperature modified

Stand by VFD ‘Run’ feedback indication was not given

Electrical Dept improvement works

Remarks

Previously all three instrument air compressor power source was fed through General auxiliary PMCC. Now for compressor-2&3, alternate power supply source was given from unit-1&2 auxiliary PMCC. Even if station transformer supply fails, power source will be available for compressor-2&3 through unit-1&2 auxiliary PMCC.

Previously all three unit battery chargers (2 chargers per unit) power source was fed through that individual STG MCC. Modified the power supply source so that any one battery charger supply will be available even if that individual unit UAT breaker and Tie breaker gets tripped. So all Units Battery bank will be always in charged condition.

Unit-1 coal feeders gets trip often during the initial time after commissioning without any alarm (unknown reason). Circuit was traced and found for all the coal feeders Neutral supply was not connected and body earth was used as neutral. Wiring was modified and rectified the problem.

In Coal handling plant Lighting distribution boards were mounted around BC-5 conveyor location. This was causing entry of dust into the DB and failure of MCB’s and lamps. Now three nos of DB have been shifted away from dust.

After commissioning unit-1 & 2 Startup booster fan Local start/stop was not working due to control wiring problem. Same was rectified.

Two Power sources are available for (MLDB) Main Lighting Distribution board-1&2 through General auxiliary PMCC & Emergency Diesel Generator Board. During Total black out changeover to Emergency DB has to be done manually which was taking more time. Automatic change over scheme was introduced to reduce the time.

For Unit-1&2 Turbine control panel & vibration panel only UPS supply was given. Non UPS supply was arranged as alternate power supply to avoid unit tripping during UPS failure.

Al l three units Generator Tri vector meter (Energy meter) often gets hang during the time of excitation. MCB was introduced in PT wiring. Now during excitation time, even if meter gets hang same can be rectified by reseting the MCB.

After unit-3 commissioning, Unit was tripping during Tie breaker to UAT changeover. Protection CT wiring was wrongly connected and Transformer Differential protection relay parameters were corrected. Then only, UAT was able to taken in line

Initially Differential protection was not connected for Boiler Feed water Pump motor-3A. Current transformer fixing and setting of relay parameters was done and differential protection was taken in line.

In star delta module, Delta contactor used to get fail whenever timer fails. Control wiring was modified so that when timer fails, neither Main nor Delta contactor will energize. After this modification the failures of contactor & fuses are avoided.

Fin Fan motors used to get stopped due to frequent failure of control relays. All three units Control wiring was modified to rectify the above problem

Earlier ESP transformer was connected through 72 KV tapping. Changed to 66KV to get energy saving.

Initially Breather was not present in Phase shifting transformer - 3A Conservator tank. Arranged and fixed the same

Power supply arrangement was done for the all three units Instrument air line Moisture separator

Unit-3 AVR trip indication not glowing in annunciation panel. Wiring was modified for the same.

Previously all three unit boiler side 1ph & 3ph supply arrangement not there so arranged the supply floor wise.

Earlier lighting distribution board at boiler area & ACC area incoming power supply was around 250 Volts. Reduced the Lighting transformers tap setting and General auxiliary transformer tap setting from ‘3’ to ‘2’. Now the voltage has reduced to around 240 Volts.

When both 6.6 KV Tie breaker and UAT breaker gets trip/Open due to any reason, Lubrication pump will not be available for turbine. Planned to feeder the AC Emergency Oil Pump motor power supply through General auxiliary PMCC. For this MR has been raised for procurement of a separate MCC panel.

Initially 28 tons package Air conditioner was installed in VFD Room. Room temperature was around 38°c to 40°c. Installed extra 38 tons of AC and another 16 tons are under installation. Room temperature is maintained around 32°c to 34°c. Now drive failures and malfunctions have reduced. Unwanted duct holes closed.

All units Stand by VFD ‘Run’ feedback indication were not connected. So wiring modification work was done for all the three units’ standby VFD panel.

Unit-3 generator DE bearing temperature not came in GPR panel while check RTD output one channel output not came from RTD, so wiring modified in GPR panel side RTD O/P taken from DCS & temperature scanner source.