Method for operating a combined cycle power plant

Abstract

A method for operating a combined cycle power plant, according to which shortly before the planned start-up of a parked load, the steam turbine is lowered to a very low output, the gas turbine is then operated in parked load, and next the steam turbine is powered up to a parked output. The GT operating power can be the rated power of the gas turbine. The ST operating power can be the rated power of the steam turbine.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is the US National Stage of International Application No. PCT / EP2014 / 064182 filed Jul. 3, 2014, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP13177932 filed Jul. 25, 2013. All of the applications are incorporated by reference herein in their entirety.FIELD OF INVENTION[0002]The invention relates to a method for operating a combined cycle power plant, wherein the gas turbine is operated at a GT operating power and the steam turbine is operated at an ST operating power, wherein the power of the steam turbine is reduced to an ST part power, wherein the ST part power is lower than the ST operating power.BACKGROUND OF INVENTION[0003]Combined cycle power plants are used to generate electrical energy for communal energy supply. In general, a combined cycle power plant supplies electrical energy to a supply grid, the energy requirement being dependent on the time pr...

AI Technical Summary

Benefits of technology

The invention proposes a method where a steam turbine is involved in a parked load, which helps to keep the grid stable. To reduce energy consumption, the steam turbine is operated at a very low power before the planned load. This allows the gas turbine to take over and use less heat transfer, which results in lower service life consumption. The pressure in the steam turbine is also reduced, which further reduces heat transfer and service life consumption during part load. Evacuation lines, drains, and other measures are used to achieve this reduction in pressure.

Problems solved by technology

Feeding-in of the renewable energies is subject to fluctuations, which leads to increasing demands on the conventional power plants.

However, this means that the hot components of the steam turbine are exposed to cold steam, which leads to thermal stresses.

If the parked load is then abandoned again, the steam temperatures rise again, which once again leads to thermal stresses.

This would lead to very low service life consumption.

Images