Cold start method of gas-and-steam combined cycle power generating unit

Abstract

The invention relates to a cold start method of a gas-and-steam combined cycle power generating unit. The cold start method specifically comprises the following steps that 1, under dragging of a static variable-frequency starting device, the rotating speed of a gas turbine is stabilized at m rpm; 2, steam is fed from adjacent machines, specifically, a turbine conducts impulse starting on a warmingturbine through an intermediate-pressure cylinder, at this time, a high-pressure cylinder forwards or reversely feeds steam, the rotating speed of the turbine is stabilized at m rpm, an SSS clutch begins to be engaged in place, the steam fed from the adjacent machines conducts impulse starting on the turbine, and the gas turbine is driven by the SSS clutch; 3, the output of the static variable-frequency starting device of the gas turbine is reduced to be 0, the quantity of the steam fed from the adjacent machines is increased, and the rotating speed of the medium-speed warming turbine is maintained for turbine warming; 4, when the calculation temperature of an intermediate-pressure shaft in the turbine is larger than 200 DEG C, the medium-speed warming turbine stage is finished, or the turbine warming time of the medium-speed warming turbine stage is determined according to the actual on-site working conditions; and 5, after the medium-speed warming turbine stage is finished, the output of the static variable-frequency starting device of the gas turbine is gradually increased, the quantity of the steam, fed from the adjacent machines, of the turbine is gradually decreased to be 0,the turning states of the gas turbine and the turbine are restored, or the turbine is controlled to be smaller than the gas turbine in ignition rotating speed, the gas turbine slows down to directlyignite, and then the combined cycle power generating unit is started in a warm or hot start mode.

Description

technical field [0001] The invention relates to the field of generator sets, and more specifically, to a cold-state starting method of a gas-steam combined cycle generator set. Background technique [0002] V94.3A gas-steam combined cycle generator set with a unit unit capacity of 390 MW. The gas-steam combined cycle generator set includes steam turbine, gas turbine and generator, among which the steam turbine is the model H30-25, E-30-25-1×12.5 (TCF1) jointly developed by SAIC and Siemens, triple pressure, reheat, double cylinder Condensing steam turbine, steam turbine, gas turbine and generator are coupled through SSS clutch to form a complete single-shaft configuration. The steam turbine includes a high pressure cylinder, a medium and low pressure synthesis cylinder. [0003] The cold start process of the above gas-steam combined cycle generator set is as follows: [0004] Trigger the start command, and the gas turbine cranking device starts to trip. After a short peri...

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Problems solved by technology

[0007] However, the V94.3A gas-steam combined cycle generator set takes a long time to start in cold state. It takes 7h to 8h for the unit to start from cold state to normal with full load. Compared with GE or Mitsubishi units of the same F class, it cannot meet the requirements of quick start to support the power grid

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