Work Instructions

Start-Up After 8 Hours of Shutdown ( Hot start-UP)

Unit condition

1	At least 2 BCW pump in Serrvice
2	Both SAPH and PAPH Running
3	Turbine : On Barring (AOP,JOP,SOP, HPCF in service)
4	Generator: PW system, Seal Oil system, Gas system

TDBFP LOP protection and Auto Start

1. LOP A running if trips, LOP B takes start

2. LOP A running and LO dis Hdr manifold pr  LT 8.4 ka, LOP takes start

3. LOP A running and LO dis pr at brg inlet LT 1.8 ka, LOP B takes start

4. If LO dis Pr at Brg inlet LT 1 ka, DCEOP starts

SCED Features

SCED Features

• NLDC has opened a separate bank account called ‘National Pool Account (SCED)’. All payments to/from the generators and to the Discoms on account of SCED flow to/from the said National Pool Account (SCED)

Power Terminology

Power Terminology

• 100MW for 24 Hrs = 2.4 MU (Million Units)
• Ancillary services refer to functions that help grid operators maintain a reliable electricity system.
• Ancillary services maintain the proper flow and direction of electricity, address imbalances between supply and demand, and help the system recover after a power system event

RH Metal Temp Optimization

RH Metal Temp Optimization

• Causes of Rh Tube Fail:  

(a) COAL ASH CORROSION FOR TUBING
(b) UNEVEN TEMPERATURE DISTRIBUTION ACROSS THE BOILER

Dry Ash system : 500 MW

Dry Ash system : 500 MW

• Ash is oxidised form of the mineral matters present in coal
• Typical ash composition : SiO2, Al2O3, Fe2O3, CaO, MgO etc
• Coal with more SiO2 & Al2O3, Ash MP > 1400ºC

NTPC Rihand Shift Rota : Year 2020

Shut-Down Procedure: 500 MW (Planned Shutdown)

Shut-Down Procedure: 500 MW

• Reduce load from 500 MW to 400 MW
• Gradualy Reduce Pr SP from 170 ksc to 130 ksc, Load is still 400 MW
• Take unit of TFM

New Regulation: Real Time Market Power Trading

Hydrogen Purging

Pre-Purging checklist:

1. The generator may be on barring gear or at standstill. Preferably be on barring speed of around 50-80rpm (without condenser vacuum).
 At least 60 CO2 filled cylinders should be available in the unit where purging is to be done.
 Arrangement for filling hot water on CO2 cylinder / lines (to avoid freezing) is to be ready.

Loss of Instrument Air

Loss of Instrument Air
Anticipated Problems:

1. No oil burner can be taken in service. Oil guns, oil/steam valves will remain inoperative.
The igniter will not get advance.

Vacuum Pulling Process

Vacuum Pulling Process
1 Ensure permit cancellation on Vacuum pump/Flash Tank related MOV/Condensate system & Clearance for vacuum pulling.

Mill Fire

Mill Fire
a) Fire in mill under shut down:
 Isolate the mill totally from air side by closing cold/hot air dampers & gates and mill seal air valves.

Shutdown Instructions

Shutdown Instructions
1 Ensure UT change over before tripping of boiler/ turbine.
2 Ensure 400 KV breaker are opened after unit tripping.

UPS Failure

UPS Failure

CONSEQUENCES OF 240 VOLT UPS SUPPLY FAILURE:-

 All LVS supplies from main UPS will not be available but from mini UPS supply will be
available for around 2 hours .

Boiler forced Cooling

Boiler Forced Cooling

1 In case of Tube leakage

1.1 After Tripping the boiler ,stop FD fan and keep ID fan running at
minimum load and ensure furnace pressure negative inside boiler.

CC(BCW) Pump Isolation & Purging

CC(BCW) Pump Isolation & Purging

1. ISOLATION OF CC PUMP REMARKS

1.1 Remove from Stand by mode if it is in auto
1.2 Stop CC pump if running

Bunker fire : Prevention

Bunker fire

PREVENTION OF BUNKER FIRE

 Ensure Feeder outlet gate closes on auto when Feeder stopped/tripped. Otherwise give
a close command for closing.

ACW pump house

Condenser : One Pass Isolation

1 Ensure the availability of both condenser de-watering pumps.
2 Decrease the load to 300 – 350 MW
3 Ensure that both CW interconnection valve are opened
4 Start Stand by Vacuum pump

Generator Air tightness Test

TEST PROCEDURE: -
1) Air Filling valve is to be opened for flushing of line & removal of moisture in atmosphere.
2) Chemistry is to take sample for dew point measurement. After chemistry clearance , Filling process
has to be continued.
3) Close the waste gas (vent) valves.

APH Hot Washing

1 Water washing of air heaters should be carried out in hot condition after boiler shutdown.Flue gas inlet temperature should be between 200 deg C to 150 deg C
2 Both FD/ID/PA fans should be in stopped condition
3 All APH flue gas outlet damper should be closed

Stopping one FD Fan

1 Reduce the load to 400 MW & then remove from CMC
2 Before Unloading FD Fan (to be stopped ),The following
Permissive & Protection to be kept bypassed :
“FD Fan ON & Discharge Gate close” permissive to be given
“FD Fan ON & Discharge gate auto open” to be bypassed.

Stopping one PA Fan

1 Reduce the load to 300 MW & then remove from CMC
2 Keep 4 consecutive Mills in service. If required , take oil guns in service

Stopping one ID Fan

1. Reduce Load to 300MW
2. Start Unloading corresponding FD fan & increase loading of other FD Fan through blade pitch.

Stopping one PAPH

• Reduce Load to 300MW
• Slowly close flue gas outlet damper for PAPH which has to be stopped

Stopping one SAPH

• Reduce Load to 300MW
• Slowly close flue gas outlet damper (2 in no. )for APH which has to be stopped
• Adjust other PAPH/SAPH flue gas outlet damper
• Close flue gas inlet damper
• Close SCAPH inlet , outlet & bypass damper. During Closing , Observe Air Flow.
• Close SAPH air outlet damper (2 in no.)
• Stop the SAPH motor once flue gas inlet temperature reduced below 150deg C
• Close Air motor main isolating valve & bypass isolating valve

LIGHT UP CHECK POINTS

BEFORE LIGHT UP ACTIVITIES

BOILER SIDE

• MAN ,MATERIAL REMOVED AND BOILER IS READY FOR LIGHT UP.
  

Water-chemistry: 500 MW

Recommended Parameter Values
1. Boiler Water – pH = 9.1-9.4
2. Boiler Water – Specific Conductivity < 20.0 μs/cm
3. Boiler Water – Silica < 100 ppb
4. Boiler Water - Phosphate = 1-2 ppm
5. Boiler Water - Chloride < 0.5 ppm