Patent ID: 8528314

Claim:
A combined cycle power plant startup system comprising: a steam turbine, the steam turbine comprising a turbine section; a heat recovery steam generator operably connected to the steam turbine for providing steam to the steam turbine, the heat recovery steam generator comprising a reheater; a condenser; and a bypass system configured to adjust the steam pressure downstream of the reheater by routing steam downstream of the reheater to the condenser, the bypass system comprising a plurality of bypass lines, a plurality of control valves operably connected to the plurality of bypass lines, a pressure gauge configured to monitor the steam pressure downstream of the reheater, and a controller programmed to communicate with the pressure gauge and operate the plurality of control valves in sequence, wherein operating the plurality of control valves in sequence comprises opening the plurality of control valves when steam downstream of the reheater reaches a fixed pressure limit, setting a first control valve to auto-control, and setting a second control valve to auto-control when the first control valve reaches a fixed valve stroke limit, and wherein setting one of the first control valve or the second control valve to auto-control comprises setting the control valve to an adjustable stroke setting, such that a stroke of the control valve automatically adjusts in order to adjust or maintain the pressure of steam downstream of the reheater at a pressure range suitable for admission to the turbine section, the steam pressure being adjusted to a pressure range suitable for admission to the turbine section.