Patent ID: 8057157

Claim:
A system for providing air from a multi-stage compressor to a gas turbine comprising: a gas turbine including a plurality of extraction air input ports including a high pressure input port, a medium pressure input port and a low pressure input port; a multi-stage compressor including a plurality of extraction air output including a high pressure extraction air output, a medium pressure extraction air output and a low pressure extraction air output; a first control valve provided between the low pressure extraction air output and low pressure input port and a second control valve being provided between the high pressure extraction air output and the low pressure input port, the first valve being selectively operated to fluidly connect the low pressure extraction air output with the low pressure input port during normal operating conditions and the second valve being selectively operated to fluidly connect the high pressure extraction air output and the low pressure input port during one of a turn down condition and operation below design temperature.