2. If
the computer has been de-energized， close the computerbreaker，start the computer， and enter time of day. Under normal conditions， the computer is left running continuously.
3. Place maintenance switches to ..Auto...
4. Acknowledge any alarm condition.
5. Check that all lockout relays are reset.
6. Position ...emote-.ocal.. switch to desired position.
Startu. description.When the unit is prepared to start， the ...eady toStart.. lamp will be lit. With local control， operating one of the following push buttons will initiate a start:
1. .oad minimum start.
2. .oad base-start.
3. .oad peak-start.
The master contactor function will accomplish:
1. Secondary auxiliary lube pump starter energized.
2. Instrument air solenoid valve energized.
3. Combustor-shell pressure transducer line drain solenoid valve energized.
When the auxiliary lube pump builds up sufficient pressure， the circuit to close the turbine gear starter will be completed. Thirty seconds are allowedfor the lube pressure to buildup， or the unit will shutdown. With the signalthat the turning-gear line-starter is pickedup， the sequence will continue..ext， the starting-device circuit is energized if lube oil pressure is sufficient. The turning-gear motor will be turned off at about 15% speed. When theturbine has reached firingspeed， the turbine overspeed trip solenoid and vent solenoid will be energized to reset. With the build up of overspeed tripoil pressure， the ignition circuit is energized.
The ignition will energize or initiate:
1. Ignition transformers.
2. Ignition time function (30 seconds allowed for establishing flame on both detectors or the unit will be shut down after several tries).
3. Appropriate fuel circuits (as determined from mode of fuel selected).
4. Atomizing air.
5. Ignition time function (to de-energize ignition at the proper time).
At approximately 50%speed， as sensed by the speed channel， the start-ing device is stopped. The bleed valves are closed near synchronousspeed， each at a particular combustor-shell pressure. After fuel is introduced and ignition confirmed， the speed reference is increased at a preset variable rate and will determine the fuel valve position set point. The characterized speed reference and compressor inlet temperature will provide a feed-forward signal that will approximately position the fuel valves to maintain the desired acceleration. The speed reference will be compared with theshaft-speed signal， and any error provides a calibration signal to ensure that the desired acceleration is maintained. This mode of control will be limited by maximum blade path and exhaust temperatures corresponding to the desired turbine inlet temperatures. If desired acceleration is notmaintained， the unit must be shut down. This control avoids many major turbine failures.
With the advance of the turbine to idlespeed， the turbine is ready tosynchronize， and control is considered in synchronization. Both manual andautomatic synchronizing are available locally. The unit is synchronized， and the main breaker closed. The speed reference will be switched to become a load reference. The speedjload reference will be automatically increased at a predetermined rate so that the fuel valve will be at the approximate positionrequired for the desired load. For maintenance scheduling， the computer will count the number of normal starts and accumulate the number of hours at the various load levels.
Shutdown. .ormal shutdown shall proceed in an orderly fashion. Either a local or remote request for shutdown will first reduce the fuel at a predetermined rate until minimum load is reached. The main and fieldbreakers and the fuel valves will be tripped. In an emergency shutdown， the main and field breakers and fuel valves will be tripped immediately without waiting for the load to be reduced to minimum. All trouble shutdowns are emergency shutdowns. The turbine will coast down and as the oil pressurefrom the motor-driven pump drops， the DC auxiliary lube oil pump willcome on. At about 15%speed， the turning-gear motor will be restarted， andwhen the unit coasts to turning-gear speed (about fiverpm)， the turning-gearover-running clutch willengage， allowing the turning-gear motor to rotatethe turbine slowly. Below ignitionspeed， the unit may be restarted; however， the unit must be purged completely of any fuel. This is accomplished by moving through the turbine at least five times its total volume flow.
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本文链接地址：燃气涡轮工程手册 Gas Turbine Engineering Handbook 3(39)
