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Hot Start

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1.0   Purpose

2.0   Overview

3.0   Procedure

3.1   Limits and Precautions

3.2   Checks and Tests

3.3   Startup

3.3.1   Hot Start Validation Checklist

3.3.2   Control Room Activity Checksheet

3.3.3  .Gas Turbine Pre-Start Checklist

3.3.4   Plant Operator Prestart Checklist

3.3.5   Start-up Procedure (Hot Start)

3.3.6   Steam Turbine Pre-Start Checklist1

3.3.7   STG Start-up1

3.4   Normal Loading1


1.0   Purpose

The purpose of this procedure is to outline the key tasks and the method that will be used to conduct a warm start of the plant. Warm start is defined as the starting of the Steam Turbine with a 1st stage or RH bowl inner-metal temperature >700F.

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2.0   Overview

The normal combined cycle Hot startup will be completed by initiating 1x1 operation and then combining the second combustion turbine/HRSG steam production together at elevated loads by opening the steam header block valves.

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3.0   Procedure

3.1   Limits and Precautions

General Plant

  • All Tagging activities must be audited and cleared prior to beginning the checklist for system operation.
  • All Hot Work should be verified completed and filed.
  • All Confined Space activities on the Units in start-up completed and filed.
  • Temporary standing orders will be reviewed and any lead lifting and jumpering activities shall be audited in accordance with PPM 5.0.
  • The operations start-up step sequence will be completed IAW 10.02. Enclosure 1.0.
  • The normal system line-ups should be verified in accordance with PPM 9.0 for any system that has been taken out of service for the shutdown.
  • All the Gas Turbine Units should be placed on turning gear 4 hours prior to starting and the CTG’s should be in cooldown mode and ready to start.
  • The Steam Turbine should be placed on turning gear 4 hour prior to operation with a minimum eccentricity reading of less than 3 mils.
  • Power and Gas nomination sheets should be submitted per the schedule prior to operations. See PPM 4.0 for Dispatching Electric Power.
  • Plant chemistry program should be placed in service and overall water availability and quality should be validated prior to starting the plant.
  • The CEMS should be operational and all daily reports verified correct and system checks completed.

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 3.2 Checks and Tests

CTG’s

  • Verify that the Units are ready to start.
  • Complete the operational checklist.
  • Sump oil temperature should be between 90 – 110 F.
  • Verify the MK V control system and the OSM are operational.
  • Verify the units are on gear and ready to start.

HRSG

  • The HRSG must be completely filled with high quality chemically treated demineralized water.
  • The entire HRSG should be walked down and vented to verify that air pockets have been eliminated during the fill process.
  • All HRSG system valves need to be properly positioned for HRSG startup.
  • All HRSG system instruments must be functional.
  • The heat tracing system must be functional.
  • All pertinent steam system prerequisites must be satisfied and the steam circuits must be available for operation with valves properly positioned for startup.
  • The cycle chemical feed system and the sampling system should be functional and ready to support operation of the HRSG.

Plant Electric System

  • The plant power system must be back fed from the 500kv system and all breakers in the normal power line-up IAW PPM 9.0.
  • Back feed demand should be limited to 12,000kv for any 15 minute period max during the starting process to stay within the agreement for purchased power.

Fuel Gas System

  • El Paso Gas System should be available and the normal line-up for the plant checked.
  • Gas operations should be notified in accordance with PPM 4.0.

Circulating Water System

  • The cooling tower level should be 35-42”. A circulating water pump should be in service with eight cells in service and tower raisers open to minimize drift effects.
  • Cooling tower chemistry should be verified with in range. All treatment systems in service.
  • Visual inspection of screens and fill should be completed if an extended shutdown was performed.

BOP Systems

  • Air compressor system operational and the lag compressors ready for service.
  • Plant water treatment in service and normal levels in all tanks.
  • Feed water system ready for service and drum levels at minimum for cold start.
  • Condensate system ready for service with hotwell level normal.
  • The Air Intake and Exhaust system is ready for operation.  Inlet and exhaust plenums and associated ducting are clean and rid of all foreign objects.  All access doors are secure.
  • All other plant systems ready for start-up in accordance with PPM 9.0.

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3.3 Startup

Once the plant conditions for a Hot Start are verified(1st stage shell or RH bowl and 1st stage inner metal temperature greater than 700F). The Pre-start checklist contained in Enclosure 1.0 shall be completed and maintained to document the required sequence and data for the start-up. The start-up is managed by the control room with individual responsibilities contained in the check sheets of Enclosure 1.0 and identified below.

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3.3.1 Hot Start Validation Checklist

Verify and Log the following conditions on the running unit prior to blending.

Activity

Pressure

Temperature

HRH

   

HP Steam

   

LP Steam

   

 

 

Date/Time Start:

______________

CRO:

_______________

 

Unit:

______________

Shift Lead:

_______________

 

Time of dispatch:

______________

   

Indicators
COLD START

Targets

Actuals

Units

Min

Max

         

1. HRH Blending Pressure

-25

25

 

PSI

2. HRH Blending Temp,  

-50

50

 

deg. F

3. HP Blending Pressure

-25

25

 

PSI

4. HP Blending Temperature

-50

50

 

deg. F

5. LP Blending  Pressure

-25

25

 

PSI

6. LP Blending Temperature

-50

50

 

deg. F

7. Time unit is ready for dispatch

     

Current Time

         

Date/Time S/U complete:

________________________

Cold start: 1st stage and RH Bowl inner-metal temperature < 400F

CRO:

________________________

Warm Start: 1st stage and RH Bowl inner-metal temperature between 400 and < 700F

PTL/O&M review:

________________________

Hot Start: 1st stage and RH Bowl inner-metal temperature > 700F

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3.3.2 Control Room Activity Check sheet

Action

Initial/Comment

Review Hot Work Binder

 

Review Confined Space Binder

 

Review LOTO for clearances that will affect Start-up

 

If maintenance was performed complete post maintenance close-out

 

Check and Verify DCS alarms and MKV

 

Review temporary standing orders and night orders, verify compliance with PPM 5.0 Lead Lifting and Jumpering

 

Ensure CEMS is in operation and clear of alarms, document in the log book by making entry.

 

Ensure Plant Fire System is in service and Auto.

 

Ensure Steam Turbine is on Turning gear and eccentricity reading is less than 3 mils.

 

Verify Plant Chemistry

 

Ensure Demin supply tanks > 60%

 

Verify Demin transfer system in service by placing 1 pump "in service", 1 pump in "auto"

 

Condensate Pump start permissives: 1 demin transfer, condensate recirc regulator open > 60%

 

Throttle condensate pump discharge valve 20% open and close BV3030/4030, start pump, upon equalization and venting of the system open the discharge valve to 100%, open BV 3030 place remaining pumps in standby.

 

Start condensate chemical injection pumps

 

Open LP feed water stop valve SGA MBV-1402/2402

 

Fill LP drum to normal level -3" and place level controls in "auto"

 

Establish condenser levels at 30”

 

Start BMS scanner blower fan place other fan in "standby"

 

Check that all the DCS startup permissives are satisfied reset GT at DCS.

 

Startup Boiler feed water pump, place other Boiler Feed water pump in standby

 

Start HRSG chemical injection pumps, fill HP drum up to -12”,IP drum up to -10” place feed water control valves in auto.

 

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3.3.3 Gas Turbine Pre-Start Checklist (Control Room Operator):

Initial Each Item as Completed

_______Perform a “Master Reset” on the MKV

_______On Mark V HMI, check all bearing drain, metal, and exhaust thermocouples are reading good quality.

_______On Mark V HMI, check Generator RTDs are reading good quality.

_______On Mark V HMI, check Generator H2 pressure and purity w/in specifications.

_______On Mark V HMI, check gas valves positions, all should be 0% open.

_______On Mark V HMI, verify all flame detector intensities are reading: 1or 0.

_______On Mark VI HMI, verify IGV control in Auto, IBH is on, IGV temp control is on, FSR Control is in Auto, and steam turbine temperature matching is off. (Temp match TBD)

_______On Mark V HMI, verify all seismic vibration probes have good readings 0.00 – 0.02

_______On Mark V HMI, check start check screen for all green except for “Control Mode equals Off”

_______On Mark V HMI, check trips screen for all green except for “Fuel Gas Hydraulic Pressure Low Trip”

_______Ensure Lube oil temperature is >90F.

_______From Mark V HMI, record all alarm drop numbers for specified unit below:

Comments:

 

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3.3.4 Plant Operator Prestart Checklist

Note: If GT readings (outside/Local) have been performed within the last 2 hours, perform only the following checklist: Otherwise, perform GT system walkdown as prescribed by operator logs.

Action

Initial/comment

Check the items below following for oil, water and containment. Verify doors closed and latched.

 

Accessory Compartment

 

Gas Compartment

 

Turbine Compartment

 

Collector End Compartment

 

Seal Oil Compartment

 

Check EX2000 Panel for alarms

 

Ensure 41AC breaker is racked in, EX2000 core breakers are energized, and fans are running.

 

Check LCI for alarms

 

Check Generator Protection Panel, ensure there are no flags on any relays and ensure all three phases are reading good voltage

 

Verify Hydrogen Purity > 98% and Scavenging Flow ~500 cc/analyzer

 

Verify Units on Turning Gear

 

Check the CO2 fire protection system for alarms, ensure manual isolation valves are open and all compartment valves are in neutral position.

 

Comments:

 

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3.3.5 Start-up Procedure (Hot Start)

_______Ensure the following MBVs are closed and in manual for the lag GT:

  • 1SGG-MBV-X001/X001 (HP Steam stop valve)
  • 1SGJ-MBV-X001/X001 (HRH isolation valve MOV)
  • 1SGH-MBVX013/X013 (LP Steam stop MOV)
  • 1SGK-MBVX012/X012 (CRH Isolation valve)

Start GT from the MKV as follows:

_______Master reset

_______Mode select AUTO,

_______Select start

_______Place all start up vents in auto/calculated set point

  • HP MCV-X139/X139
  • IP SH MCV-X314/X314
  • HRH MCV-X627/X627
  • LP MCV-X518/X518

_______Place SCR Blower in service.

_______Verify all HRSG and steam bypass Attemporators are in “auto”

Verify the following during the GT purge cycle for the starting GT:

_______Cycle all HRSG START UP drains in sequence (HP, IP, & LP), to remove any condensation from steam lines prior to opening steam isolation valves.

_______Open all steam line drains.

  • HP ABV-X141,X017,X019,X020,X001,X002,X011,X012
  • IP ABV-X004,X005,X017,X001,X002,X005,X009
  • CRH-ABV-X010,X019
  • LP ABV-X006,X022,X009

_______Perform the following prior to GT fire:

  • Open 1SGJ-MBV-X001/X001  (HRH isolation valve MOV)
  • Open 1SGG-MBV-X001/X001  (HP Steam stop valve)
  • Open1SGH-MBVX013/X013  (LP Steam stop MOV)
  • Open1SGK-MBVX012/X012  (CRH Isolation Valve)
  • Open1SGA-MBV X316/X316  (IP SH isolation valve)

_______Set/verify the IP Drum Press Control (1SGA-ACVX315/X315) at 250 psi.

Note:  If enough HP Steam Supply press is available (500psi@>300degf), commence establishing a vacuum. If  HP pressure is not available this step will be followed after GT is fired and steam quality (temp/press) exists

  • “In manual operation” Place HP to CRH bypass at 12% open
  • Continue to slowly open HP to CRH bypass up to 20% to maintain HP pressure at 750psi
  • With HP steam pressure at 725 place HP to CRH by pass in auto with set point of 750psi
  • Place steam seals in service at 3.5 psi (min 175psi in HP header with a temp. of 300°F min)
  • Open HRH start up vent (MCV-X627) to ensure steam path requirements.
  • Slowly close HRH start up vent (MCV-X627) once by passing has commenced.
  • Ensure the gland seal exhauster is running (1-BLO-X00 A/B)
  • Place both condenser vacuum pumps in service.
  • After vacuum pumps are in service, close the vacuum breaker
  • At 2.5 psia vacuum, secure one vacuum pump and place in standby
  • At 4.91 PSIA bypass operation may commence(~20” vacuum), set SGG 1008/1008(HRH bypass) to 80 in auto psi.
  • Set SGHX 1010/2010 (LP bypass) to 55 psi in auto.

_______Record GT start time in control log

  • Place start up Fuel Gas heater (X002/X002) in service.
  • Ensure all HRSG start up drains are closed after cycling.
  • Close all steam line drains and place in auto except (STG Start Permissive):
  • HP ABV-X011,X012
  • IP ABV-X001,X002,X005,X006

_______Record time GT breaker is closed.

_______Place GT MW load at 33

_______Ensure Fuel Gas performance heater temperature control regulator is operating in auto

Note: Once vacuum is established and by pass requirements are satisfied And if Fuel Gas Temperature conditions are met raise GT load to >90 MW to Support mode 6Q.

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3.3.6 Steam Turbine Pre-Start Checklist:

Control Room Operator:

Action

Initial / Comment

Ensure 86G lockouts are reset

 

On the MKV ensure that all bearing drain, metal, and exhaust thermocouples are reading good quality.

 

Check EX2000 Faults

 

Verify Hydrogen Purity > 98% and Scavenging flow > 500cc

 

Verify STG is on Turning Gear (eccentricity < 3mills)

 

Ensure all MKV, HMI permissives are satisfied.

 

Verify all Group A, B, C Drains are in “Auto” on the MKV

 

Verify Lube Oil Temp > 80 F.

 

Record Condenser vacuum, < 2.5psia required to roll

 

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3.3.7 STG Start-up

NOTE:  IF OPERATOR ROUNDS HAVE NOT BEEN PERFORMED WITHIN THE LAST 2 HOURS PLEASE RECHECK ITEMS PERTAINING TO ONLY STG IN THE OPERATOR LOG SHEETS 1-3

Roll the Steam Turbine in “Auto” as follows:

_______Reset the Steam Turbine on DCS

_______Reset the Steam Turbine on Mark V

_______Select "Auto" mode

_______Select "Start"

_______Select “Hold off”

During the roll closely monitor the following:

_______HP exhaust temperature limits

Alarm 850 degf

Trip 900degf

_______LP Temperature Limits

Alarm 400 degf

Trip 450 degf

_______Exhaust Temperature Limits

Alarm 200 degf

Trip 225 F

_______Allowable vibration

Alarm 6 mils

Trip 9 mils

_______Differential expansion limits

Alarm DEDX-1 long rotor  + 386

Trip DEDX-1 long rotor  + 486

Alarm REDX-1 long rotor  + 616

Trip REDX-1 long rotor  + 720

Alarm DEDX-1 short rotor  -260

Trip DEDX-1 short rotor  -290

Alarm REDX-1 short rotor  -287

Trip DEDX-1 short rotor  -317

_______Turbine speed will hold at 3000 RPM until lube oil temperature reaches approximately 100 degf.

_______At 3600 rpm synchronize the STG ( in auto synch mode), Record time in logbook.

_______Ramp ST (15% LOAD COMMAND) to support forward flow.

_______Place LP admission valve at 20% flow command ramp flow rate in 10% increments once 100% flow is achieved raise LP bypass  to condenser setting to 90 psi.

_______In auto forward flow mode will transfer automatically (When ST  IV’s open > 50%) at this time raise HP to CRH and HRH bypass set points to (1200 psi HP to CRH) (350 psi,RH bypass) place bypass valves in calculated set point

_______Ramp GT load if required to meet generation schedule. .

_______With HP steam pressure at 800 psi and rising select the IPC “ON” and lower IPC setpoint to 600 psi in 10% increments.Check DCS screens insure that all HRSG and Steam Turbine drains are closed, check MK V screens insure that all group A, B, and C drains are closed.

_______Record time GT reaches mode 6Q.

_______GT in Mode 6Q & 600F(TBD) catalyst temp, place SCR in service

_______Ramp drum levels to normal levels, place in 3 element control, set cascading blowdown regulators at desired position as per boiler chemistry results.

_______Ensure LP recirc temperature control regulator is in auto, start LP recirculation pump.

_______Adjust plant load as necessary to support generation schedule.

_______Check VARS

_______Align chemical injection pumps as necessary.

_______Verify HRSG in 3-element drum level control.

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3.4 Normal Loading

Maintain Generator VARS at unity at all times unless director by SRP dispatch. Normal loading is accomplished by adjusting the load set-point on the turbine overview screen.  Monitor and maintain load within the PaloVerdi congestion management set point for the day as nominated in PPM 4.0.

4.0 REFERENCES

GEK

GE Manuals Gas and Steam Turbines

NE Manuals

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