A method for block loading an electrical grid with a combined cycle power plant (CCPP) includes operating a gas turbine system of the CCPP in an islanding mode with a steam turbine system of the CCPP off line with turning gear rotating only; loading the steam turbine system accordingly to temperature matching conditions of the steam turbine system, the loading of the steam turbine system includes controlling gas turbine exhaust fed to the steam turbine system and the gas turbine exhaust temperature heats the steam turbine system and to meet temperature matching conditions of the steam turbine system; wherein controlling gas turbine exhaust includes controlling fuel flow and air flow to the gas turbine system; and operating at least one of the gas turbine system and steam turbine system to block load the electrical grid from a load on at least one of gas turbine system and steam turbine system.

This single-shaft combined cycle plant comprises: a power generator; a gas turbine; a steam turbine that is driven by using waste heat from the gas turbine, and is connected to the power generator by a clutch when the rotational speed syncs with the rotational speed of the gas turbine; a steam turbine over-rotation prevention device; a gas turbine over-rotation prevention device; and a control device. The control device sets the power generator to an unloaded state and, whilst maintaining the rotational speed Ng of the gas turbine so as to be higher than the rotational speed Ns of the steam turbine and lower than the maximum rotational speed Nglim of the gas turbine, increases the rotational speed Ns of the steam turbine to the maximum rotational speed Nslim of the steam turbine (time t2-t4) and tests whether or not the steam turbine over-rotation prevention device operates normally.

A plant monitoring device (20) is provided with: a state quantity acquiring unit (211) which acquires state quantities for each of a plurality of characteristic items relating to a plant; an abnormality degree calculating unit (212) which calculates a degree of abnormality representing a degree of approach toward an abnormal side relative to a limit value that is predetermined for each characteristic item, for the state quantities acquired at a plant monitoring timing; a distance calculating unit (213) which uses a statistical technique to calculate distances representing the degrees of separation, from the normal operating state of the plant, of the state quantity and the degree of abnormality acquired at the monitoring timing; and a determining unit (214) which determines the operating state of the plant on the basis of the calculated distances.

A steam turbine plant is provided with: a boiler; a fuel valve; a low-temperature steam generation source; a steam turbine; a main steam line that guides steam generated in the boiler to the steam turbine; a main steam adjustment valve that is provided to the main steam line; a low-temperature steam line that guides low-temperature steam from the low-temperature generation source to a position closer to the steam turbine-side than the main steam adjustment valve in the main steam line; a low-temperature steam valve provided to the low-temperature steam line; and a control device. During a stopping process of the steam turbine plant, the control device sends a command to close the fuel valve, and then sends a command to open the low-temperature steam valve.

A method for improving the efficiency of a Rankine cycle by reducing cold end loss, comprising: for a Rankine cycle with a reheat-cycle, reducing temperature of reheat steam or removing a reheat steam system, and for a Rankine cycle with regenerative steam extraction-heat, reducing temperature of main steam and increasing humidity of main steam.

A CCPP includes a gas turbine, a HRSG, a steam turbine a flash tank and first and second supply lines. The gas turbine, the HRSG and the steam turbine are interconnected to generate power. The gas turbine may include an air preheating system to preheat the air supplied in the gas turbine to enable expedite combustion therein. The flash tank is fluidically connected at a cold end of the HRSG to extract waste hot water from the cold end. Further, the first supply line is configured to interconnect the flash tank and the steam turbine to supply of flash steam to the steam turbine. Furthermore, the second supply line is configured to interconnect the flash tank and the air preheating system to supply hot flash condensate thereto.

A system includes a combustion power plant for generating power and an electrolysis unit for producing hydrogen. The combustion power plant has a combustion chamber for combustion of a fuel and an offgas conduit for leading off hot offgases formed in the combustion of the fuel. The offgas conduit is thermally coupled to the electrolysis unit. A method for operating the system includes burning the fuel in the combustion power plant, forming the hot offgases in the combustion of the fuel, removing the hot offgases through the offgas conduit, feeding the thermal energy of the hot offgases from the offgas conduit to the electrolysis unit, and producing hydrogen in the electrolysis unit by using the thermal energy from the hot offgases.

A hybrid power plant system including a gas turbine system and a coal fired boiler system inputs high oxygen content gas turbine flue gas into the coal fired boiler system, said gas turbine flue gas also including carbon dioxide that is desired to be captured rather than released to the atmosphere. Oxygen in the gas turbine flue gas is consumed in the coal fired boiler, resulting in relatively low oxygen content boiler flue gas stream to be processed. Carbon dioxide, originally included in the gas turbine flue gas, is subsequently captured by the post combustion capture apparatus of the coal fired boiler system, along with carbon diode generated by the burning of coal. The supply of gas turbine flue gas which is input into the boiler system is controlled using dampers and/or fans by a controller based on an oxygen sensor measurement and one or more flow rate measurements.

Various embodiments include a system having: at least one computing device configured to monitor a combined-cycle (CC) power plant during a transient event by performing actions including: determining whether a change in an operating condition of a component of the CC power plant is unintentional, the determining including comparing control system instructions for the component of the CC power plant with a reference look-up table, the reference look-up table including correlation data for the control system instructions for the component and historical data about the operating condition of the component; and providing instructions to a control system of the CC power plant to modify the operating condition in the CC power plant in response to determining that the change in operating condition of the component is unintentional.

A level control system for controlling the liquid level in a boiler drum is provided. The level control system uses an integration parameter when operating in a non-transient condition to provide a control signal into a flow control loop controlling a level control valve for the liquid level in the boiler drum. When a transient condition is identified by a predictive controller, the integration parameter is interrupted and a gain vector is generated to modify the control constants and optionally modify feedforward to adjust control signal into the flow control loop during transient operation of the level control valve.