Alstom Technology Limited

Ansaldo Energia Switzerland Ag

Herbert Fuchs

Anton Nemet

Hans Wettstein

Jürgen Gerhard Hoffmann

Jürgen Hoffmann

A gas turbine and method are disclosed by which the gas turbine can be safely operated at nominal speed with reduced margin to a surge limit of a compressor. The gas turbine, via a directly driven generator which generates alternating current with an operating frequency and which is connected in a frequency-coupled manner to an electricity grid, can deliver electric power to this grid. In the case of an underfrequency event the compressor of the gas turbine is unloaded by controlled, fast closing of the variable compressor guide vanes (VGV) and as a result maintains a sufficient margin to the surge limit of the compressor.

Gas turbine and method for its operation

A method is provided for operating a gas turbine plant, in which compressed air is extracted from a compressor and for cooling is directed in an internal cooling passage through thermally loaded components to the combustion chamber and/or to the turbine, then re-cooled, and added to the compressor main flow in the compressor. At least a portion of the recirculated air is supersaturated, or partially saturated, with drops of water during or before recirculation into the compressor and a cooling mist is created. A gas turbine plant is provided with a closed cooling circuit which, for implementing the method, includes an injection arrangement for introducing water into the recirculated cooling air.

Method for cooling a gas turbine plant and gas turbine plant for implementing the method

A method for controlling a gas turbine, including during transient operating states, and such a gas turbine are provided. The gas turbine includes a compressor for compressing inducted combustion air, a combustion chamber for generating hot gas by combusting a fuel with the aid of the compressed combustion air, and a multistage turbine for expanding the generated hot gas and performing work. The controlling of the gas turbine is carried out in accordance with the hot gas temperature which is derived from a plurality of other measured operating variables of the gas turbine. A reliable controlling of the gas turbine is achieved, even during rapid changes, by pressure measurements being gathered exclusively at different points of the gas turbine for derivation of the hot gas temperature.

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Nussbaumen, Switzerland

Herbert Fuchs