Patent ID: 6324829
Filing Date: 2001-12-04
Classification: F01K,Y02E,Y02P

Abstract:
An operating method of a steam cooled system in a combined cycle power plant comprising a combination of a gas turbine plant and a steam turbine plant, said combined cycle power plant including:a gas turbine, said gas turbine including a turbine cylinder and a high temperature portion;a steam turbine;a waste heat recovery boiler for generating steam turbine driving steam using waste heat of said gas turbine;a steam cooled system using steam for cooling said high temperature portion of said gas turbine; anda steam recovery system for recovering superheated steam coming from said steam cooled system into said steam turbine;wherein said operating method comprises:providing a high temperature control valve at a cooling steam outlet of said high temperature portion; andcontrolling said high temperature control valve so as to perform cooling steam temperature control so that the temperature of cooling steam coming out of said high temperature portion is set to a predetermined value and to perform cooling steam pressure control, which is preferential to cooling steam temperature control, so that pressure of the cooling steam coming out of said high temperature portion may not become lower than pressure in said turbine cylinder of said gas turbine.