A turbine overspeed control system for a gas turbine electrical powerplant. The
powerplant may employ an aeroderivative gas turbine engine for producing electrical
power. The overspeed control system preferably comprises a compression relief system
and an air directing system. When an overspeed condition of the gas turbine engine
is detected, the compression relief system acts to remove air from a combustion
section of the engine. Preferably, the air is removed to the atmosphere. The air
directing system operates to ensure that air entering a compressor section of the
gas turbine engine does not impinge on the blades of a compressor turbine located
therein at the optimum angle. The result of operating the compression relief and
air directing systems is a reduced combustor efficiency. Consequently, a reduced
amount of hot gases are available to drive the turbines of the gas turbine engine,
and the rotational speed thereof decreases.
