Abstract: In a method for controlling a waste heat recovery steam generator of the once-through steam generator type in a combined cycle power plant, the flow volume of the feedwater into the steam generator is controlled based on a measured steam temperature at the outlet of a superheater and on a set-point value for the steam temperature for a steam turbine. A degree of superheating at the outlet of a high-pressure evaporator, a degree of subcooling at the inlet into the high-pressure evaporator, and the measured current flow volume of the feedwater are integrated in the control system in a plurality of control steps. For an optimum operation during rapid load changes, the method especially comprises additional controlling of the degree of subcooling of the flow medium at the inlet into the high-pressure evaporator.

Abstract: A method for starting-up a steam turbine of a combined-cycle power plant is provided. The combined-cycle power plant includes a gas turbine and a steam power generation system having a steam turbine. The combined-cycle power plant activates at least one electric generator connectable to an electric grid. The gas turbine includes a compressor, such that, during starting-up of the steam turbine, both the gas turbine and the steam turbine are in operation. The steam turbine adjusts its load as a function of the load of the gas turbine in such a way that the sum of the load provided by the gas turbine and of the load provided by the steam turbine is equal to the auxiliary power demand of the plant. The load exported to the grid is equal to zero.

Abstract: The disclosure refers to a method for providing a frequency response for a combined cycle power plant connected to an electric grid. The combined cycle power plant includes a gas turbine engine and a steam turbine engine. The steam turbine engine includes a boiler, a steam turbine, a pump, a condenser, a bypass for the steam turbine, a steam admission control valve. The steam turbine engine operates with the bypass closed or at least partly open to supply steam from the boiler to the condenser bypassing the steam turbine, and/or with the steam admission control valve at least partly open. The method comprises regulating the output load of the combined cycle power plant by regulating the steam admission control valve and/or by regulating the steam flow through the bypass in response to a frequency change of the electric grid. The output of the gas turbine can also be adjusted, such that steam generated by the boiler is sufficient to achieve the target load for the steam turbine.

Abstract: Method for operating a combined-cycle power plant is provided. The plant includes at least a gas turbine and at least a steam power generation system. The plant activates at least one electric generator connectable to an electric grid, wherein the gas turbine includes a compressor. The steam power generation system includes a steam turbine, a heat recovery steam generator and a bypass line. The method is such that the gas turbine de-loads to a condition, where the compressor operates at its nominal speed. The method is such that the steam turbine de-loads in coordination with the de-load of the gas turbine, to a condition where the total load exported by the plant to the grid is substantially equal to zero, being both the gas turbine and the steam power generation system connected.

Abstract: The invention relates to a method for operating a steam power plant, particularly a combined cycle power plant, which includes a gas turbine an a steam/water cycle with a heat recovery steam generator, through which the exhaust gases of the gas turbine flow, a water-cooled condenser, a feedwater pump and a steam turbine. A cooling water pump is provided for pumping cooling water through said water-cooled condenser. Evacuating means are connected to the water-cooled condenser for evacuating at least said water-cooled condenser. The method relates to a shut down and start-up of the power plant after the shutdown.

Abstract: A combined cycle system where steam discharged from a water separation unit is routed through a high pressure outlet line to a set of super-heaters and discharged from the set of super-heaters through a main outlet line of a heat recovery steam generator to be introduced into the steam turbine. An attemperating line is connected between the high pressure outlet line and the main outlet line of the heat recovery steam generator to introduce a portion of steam that is discharged from the water separation unit into the steam discharged from the set of super-heaters. The pressure difference across a control valve for steam temperature remains low in low load and/or high load applications of the combined cycle system.

Abstract: A reliable and flexible black start network restoration for a combined cycle power plant can be achieved by synchronizing a steam turbine and ramping that steam turbine up to an operating point where a maximum power increase is achieved. The resulting steam turbine load change can be compensated by the gas turbine. The increase in the demanded load can be provided by the steam turbine. The load of the steam turbine can also be gradually reduced to increase its load-increasing capacity.

Abstract: The method for operating a power plant including a gas turbine and a steam power generation system that activate, or drive, at least one electric generator, wherein the gas turbine produces flue gases that are supplied into a boiler of the steam power generation system. In a steady operation, the gas turbine generates a first output power greater than zero, the steam turbine generates a second output power greater than zero, and a total generated power is a sum of the first and second output powers and is substantially equal to a house load of the power plant.

Abstract: The invention relates to a method for operating a steam power plant, particularly a combined cycle power plant, which includes a gas turbine an a steam/water cycle with a heat recovery steam generator, through which the exhaust gases of the gas turbine flow, a water-cooled condenser, a feedwater pump and a steam turbine. A cooling water pump is provided for pumping cooling water through said water-cooled condenser. Evacuating means are connected to the water-cooled condenser for evacuating at least said water-cooled condenser. The method relates to a shut down and start-up of the power plant after the shutdown.

Abstract: A method for primary regulation of a combined gas and steam turbine installation in network operation, wherein the combined gas and steam turbine installation includes a gas turbine and a steam turbine arranged along at least one shaft includes operating at least one steam turbine actuating valve on a restricted basis along a working steam supply line to at least one pressure stage of the steam turbine so as to provide a steady-state steam turbine reserve power, wherein the at least one steam turbine actuating valve is changed to a less restricted state if a network frequency decreases so as to require network frequency support.

Abstract: A method for starting-up a steam turbine of a combined-cycle power plant is provided. The combined-cycle power plant includes a gas turbine and a steam power generation system having a steam turbine. The combined-cycle power plant activates at least one electric generator connectable to an electric grid. The gas turbine includes a compressor, such that, during starting-up of the steam turbine, both the gas turbine and the steam turbine are in operation. The steam turbine adjusts its load as a function of the load of the gas turbine in such a way that the sum of the load provided by the gas turbine and of the load provided by the steam turbine is equal to the auxiliary power demand of the plant. The load exported to the grid is equal to zero.

Abstract: Method for operating a combined-cycle power plant is provided. The plant includes at least a gas turbine and at least a steam power generation system. The plant activates at least one electric generator connectable to an electric grid, wherein the gas turbine includes a compressor. The steam power generation system includes a steam turbine, a heat recovery steam generator and a bypass line. The method is such that the gas turbine de-loads to a condition, where the compressor operates at its nominal speed. The method is such that the steam turbine de-loads in coordination with the de-load of the gas turbine, to a condition where the total load exported by the plant to the grid is substantially equal to zero, being both the gas turbine and the steam power generation system connected.

Abstract: The disclosure refers to a method for providing a frequency response for a combined cycle power plant connected to an electric grid. The combined cycle power plant includes a gas turbine engine and a steam turbine engine. The steam turbine engine includes a boiler, a steam turbine, a pump, a condenser, a bypass for the steam turbine, a steam admission control valve. The steam turbine engine operates with the bypass closed or at least partly open to supply steam from the boiler to the condenser bypassing the steam turbine, and/or with the steam admission control valve at least partly open. The method comprises regulating the output load of the combined cycle power plant by regulating the steam admission control valve and/or by regulating the steam flow through the bypass in response to a frequency change of the electric grid. The output of the gas turbine can also be adjusted, such that steam generated by the boiler is sufficient to achieve the target load for the steam turbine.

Abstract: A method is provided for operating a combined cycle power plant. Flue gas of a gas turbine is used for producing steam for a steam turbine. A reliable and flexible black start network restoration is achieved by: a) in island mode, supplying internal consumers by the gas turbine, the operating point of which is selected so that a minimum steam temperature is achieved; b) in island mode, the steam turbine is synchronized and ramped up to an operating point where a maximum power increase is achieved, the resulting steam turbine load change is compensated by the gas turbine; c) consumer loads are connected blockwise; d) the increase in the demanded load being provided by the steam turbine; e) the load of the steam turbine is gradually reduced increasing its load-increasing capacity; and steps c)-e) are repeated until the power plant's base load is achieved.

Abstract: The method for operating a power plant including a gas turbine and a steam power generation system that activate, or drive, at least one electric generator, wherein the gas turbine produces flue gases that are supplied into a boiler of the steam power generation system. In a steady operation, the gas turbine generates a first output power greater than zero, the steam turbine generates a second output power greater than zero, and a total generated power is a sum of the first and second output powers and is substantially equal to a house load of the power plant.

Abstract: In a method for controlling a waste heat recovery steam generator of the once-through steam generator type in a combined cycle power plant, the flow volume of the feedwater into the steam generator is controlled based on a measured steam temperature at the outlet of a superheater and on a set-point value for the steam temperature for a steam turbine. A degree of superheating at the outlet of a high-pressure evaporator, a degree of subcooling at the inlet into the high-pressure evaporator, and the measured current flow volume of the feedwater are integrated in the control system in a plurality of control steps. For an optimum operation during rapid load changes, the method especially comprises additional controlling of the degree of subcooling of the flow medium at the inlet into the high-pressure evaporator.

Abstract: A method for primary regulation of a combined gas and steam turbine installation in network operation, wherein the combined gas and steam turbine installation includes a gas turbine and a steam turbine arranged along at least one shaft includes operating at least one steam turbine actuating valve on a restricted basis along a working steam supply line to at least one pressure stage of the steam turbine so as to provide a steady-state steam turbine reserve power, wherein the at least one steam turbine actuating valve is changed to a less restricted state if a network frequency decreases so as to require network frequency support.

Abstract: After the economizer, an injection water pipe branches off the connecting pipe between economizer and evaporator in order to control the steam temperature. The injection water pipe is provided with a control device for controlling the injection water flow. The injection water flowing through the injection water pipe is injected into the steam coming from the evaporator at a mixing point located before the superheater. In order to control the position of the control device in the injection water pipe, the enthalpy at the superheater outlet is calculated from the parameters pressure and temperature and is compared with a desired enthalpy resulting from the desired parameters.

Abstract: The device for precontrolling the feedwater quantity of a cooling-air temperature controller (1) for a once-through cooling-air cooler (2) in combined power plant systems comprises a function element which has as inputs the signals corresponding to the air-outlet desired temperature (.THETA..sub.a soll), the air-inlet temperature (.THETA..sub.e), the air volume flow (M), the main steam pressure (p) and the water-inlet temperature (.theta..sub.e), and as outputs the signals of the approximated precontrolled feedwater volume flow (m.sub.FFO) and the controller gain (VR). A correcting quantity depending on the load (L) and the ambient temperature (T.sub.U) is additionally introduced for operation in the unsaturated temperature range.