Combined cycle electric power plant with coordinated plural feedback turbine control
First Claim
1. A control system for controlling a combined cycle electric power plant, said plant having a plurality of gas turbines, at least one steam turbine, a heat recovery steam generator connected to deliver steam to said steam turbine, and at least two afterburners connected to receive exhaust gas from responsive gas turbines and deliver heated exhaust gas to said steam generator, said control system comprising:
- a. a plurality of control modes for controlling a selected configuration of said turbines and afterburners;
b. means for operator selection of one of said control modes for controlling each of said turbines and afterburners;
c. plant monitoring means interconnected with said control system, said system having means for automatically switching the selected mode control configuration as a function of monitored plant operating conditions;
d. said plurality of control modes providing respective levels of automatic control, the highest level mode comprising a first control path for determining gas turbine load control signals for control of said gas turbines as a function of the difference between plant load demand and the steam turbine load, a second control path for determining a setpoint control signal for control of said afterburners, and a third path generating a plant load error signal as a function of the difference between monitored plant load and desired plant load, and means for incorporating said error signal into said first and second paths to modify the respective determined control signals.
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Accused Products
Abstract
A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. The steam generator includes a superheater tube through which a fluid, e.g. water, is directed to be additionally heated into superheated steam by the exhaust gas turbine gases. An afterburner further heats the exhaust gas turbine gases passed to the superheater tube. The temperature of the gas turbine exhaust gases is sensed for varying the fuel flow to the afterburner by a fuel valve, whereby the temperatures of the gas turbine exhaust gases and therefore of the superheated steam, are controlled. A plant load demand error signal is utilized for correcting a coordinated gas turbine load reference and for trimming a feedforward afterburner control signal derived from the sensed gas turbine exhaust temperatures.
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Citations
12 Claims
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1. A control system for controlling a combined cycle electric power plant, said plant having a plurality of gas turbines, at least one steam turbine, a heat recovery steam generator connected to deliver steam to said steam turbine, and at least two afterburners connected to receive exhaust gas from responsive gas turbines and deliver heated exhaust gas to said steam generator, said control system comprising:
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a. a plurality of control modes for controlling a selected configuration of said turbines and afterburners; b. means for operator selection of one of said control modes for controlling each of said turbines and afterburners; c. plant monitoring means interconnected with said control system, said system having means for automatically switching the selected mode control configuration as a function of monitored plant operating conditions; d. said plurality of control modes providing respective levels of automatic control, the highest level mode comprising a first control path for determining gas turbine load control signals for control of said gas turbines as a function of the difference between plant load demand and the steam turbine load, a second control path for determining a setpoint control signal for control of said afterburners, and a third path generating a plant load error signal as a function of the difference between monitored plant load and desired plant load, and means for incorporating said error signal into said first and second paths to modify the respective determined control signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification