Method for operating a gas and steam turbine installation for frequency support

Abstract

A method for operating a gas and steam turbine system having a gas turbine, a steam turbine and a waste heat steam generator is provided herein, wherein steam for the steam turbine can be generated in the exchange of heat with exhaust gas from the gas turbine. Absorption capacity of the steam turbine can be increased and pressure in the waste heat steam generator can be lowered to utilize storage reserves in the waste heat steam generator for increased generation of steam to assist the frequency in the power system starting from a steady-state operating mode. Thermal energy is fed to the waste heat steam generator wherein a power profile of the gas and steam turbine system is greater than or equal to a preceding power level of the steady-state operating mode to increase the absorption capacity of the steam turbine and reduce pressure in the waste heat steam generator.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is the US National Stage of International Application No. PCT / EP2012 / 071478 filed Oct. 30, 2012, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP11188956 filed Nov. 14, 2011. All of the applications are incorporated by reference herein in their entirety.FIELD OF INVENTION[0002]The invention relates to the frequency support operation of a gas and steam turbine installation.BACKGROUND OF INVENTION[0003]The energy market increasingly requires highly flexible power station installations which, in addition to short startup and shutdown times, can also cover a large power range and are well prepared for frequency support operation.[0004]This also includes, inter alia, the ability to free up additional power in the event of high electricity demand (what is termed peak load operation). In this context it will be expected in the future that power stations which are ope...

AI Technical Summary

Benefits of technology

The invention provides a method for improving the power reserve of a gas and steam turbine installation by using storage reserves in the waste heat steam generator to generate additional steam. This method prevents a drop in power output and allows for control power at partial and full load. It also increases flexibility and profitability of the power station installation, leading to increased revenue and making the operation more profitable. This method allows for a wider load range and flexibility in low load operation. The heat energy is supplied by increased power from the gas turbine and an increased flow of exhaust gas.

Problems solved by technology

In addition, it is not necessary to run the installation in what is termed modified sliding-pressure operation which, as a consequence of throttling back the steam turbine control valves, causes losses in power and efficiency during standby operation of the installation.

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