Patent ID: 8904803
Filing Date: 2014-12-09
Classification: F02C,F05D,F23N,F23R,Y02T

Abstract:
1. A method for controlling an operating point of a gas turbine that includes a compressor, a combustor and at least a turbine, the method comprising: determining an exhaust pressure at an exhaust of the turbine; measuring a compressor pressure discharge at the compressor; determining a turbine pressure ratio based on the exhaust pressure and the compressor pressure discharge; calculating a primary to lean-lean mode transfer threshold reference curve as a function of the turbine pressure ratio, wherein the primary to lean-lean mode transfer threshold curve includes operating points of the gas turbine at which an operation of the gas turbine is changed between a primary mode and a lean-lean mode; and controlling the gas turbine to change between the primary mode and the lean-lean mode; wherein the primary mode is defined as providing more than half of the fuel to primary burners of the combustor and igniting the provided fuel in a primary region of the combustor only, the primary region being adjacent to a secondary region; and wherein the lean-lean mode is defined as providing fuel to both the primary burners and the secondary burner and burning the provided fuel both in the primary region and the secondary region.