ELECTRICAL SYSTEM (LT) INSTALLATION , PRE-COMMISSIONING , COMMISSIONING OF DIFFERENT LTMCC -ABC OF THERMAL POWER PLANT PART -II

415 Volts LT switch gear consists of two bus sections A&B with a bus coupler between them. The two sections are fed from two individual power transformers 1A and 1B in case of switchboard & up stream breakers in case of MCCs & ACPs.The Transformers get their supplies from 11 KV unit switchgear feeders TRF1 & TRF2.  415 Volts Unit service switchboard feeds the boilers and turbine auxiliaries,(MCCS) Soot blower MCCs,Battery chargers(220 V ,24 V DC) Emergency switch gear and other unit auxiliaries.The single line diagram of the Unit service switchboard is given below :

LT SWITCHGEARS in typical 500 mw Project:     

I.SWITCHBOARDS

1.  Unit emergency switchboard

2.  Unit Service Switchboard

3.  ESP-1 to 4 LT Main switchboard

4.  Station service switchboard

5.  Ash system compressor switchboard

6.  Ash water Power House switchboard

7.  Off side plant services switchboard

8.  Switch yard Service Switchboard

9.  CHP Switchboard-1

10.    CHP Switchboard-3

11.    CWPH Switchboard

12.    ADM Bldg. Switchboard

13.    Raw Water Pump House Switchboard

14.    Ash Water Re circulation Service switchboard

15.    Sea Water Power House switchboard

16.    Bunker service switchboard

17.    Sweet Water Makeup Power House switchboard

II Motor Control Centres

1.  Turbine MCC

2.  Turbine valves MCC

3.  Coal mill MCC

4.  Boiler MCC

5.  Boiler Valve MCC

6.  Boiler Damper MCC

(

7.  Boiler AC Distribution Board

8.  Track Hopper MCC

9.  PT MCC

10.    DM Plant MCC

11.    CMB MCC

12.    ETP MCC

13.    Hydraulic Generation Plant MCC

14.    Chimney lighting MCC

15.    Emergency Chimney board

16.    ESP Area MCC

17.    ESP A/C & Vent MCC

18.    Ash SILO MCC ()

19.    Air Washer MCC

20.    AC & Vent MCC (

21.    Aux. Boiler MCC

22.Station AC Distribution Board

III.Aux Control Panels:

ESP – 1 to 4 Aux Control Panels 

FOUNDATION OF MCC ROOM WHERE PANEL WILL BE INSTALLED . PANELS ARE BEING SHIFTED FOR ERECTION. TRAYS FOR CABLE IS RUNNING BELOW THE  PANEL.

LOCATION OF MCC ROOM IN THE POWER HOUSE 

PANEL LINED UP FOR ERECTION.

Every 415 V LT  switch gear consists  of a number of equipment and it is proposed that these will be checked individually using standard check lists and test procedures which will be recorded in the testing schedule. Items like transformers (LT and HT side) , Breaker and its circuit, different type of relays and their settings , Bus bars etc. If these equipments are checked individually then commissioning of the particular system will take very less time. All organisation prepared detailed documentation for checking the same . Some of the organisation also outlined about the IMTE required for the testing and also tools are required to do testing work.

STATUS OF THE PLANT.

All panels are erected , aligned and individually tested for any mechanical damage . Also check all the power contractors ( a waring was issued in last despatch.

Testing equipment required.

1. Variable 03 phase 415 v AC supply and also 220 v DC supply.

2. Insulation tester (megger) hand operated / electronically operated 500V

3 Digital multimeter ( 3 and half digit).

4. Analogue multimeter , Ampere meter , voltmeter 

5. Phase sequense meter.

6. Injection test kit for injecting current /voltage to relays for testing cut in and cut out

7. Micro ohm meter 

8. Battery operated continuity tester .

9. Hand tools of standard size and make.

All IMTE must calibrated and certificate should be available with leader .Cross reference to be mentioned in the testing report.

continued to PART -III