Method and apparatus for detecting burner blowout

A method for operating a gas turbine power plant of the type including a gas turbine engine having a burner receiving a fuel flow and compressed air, the burner for providing ignition of said fuel flow to produce an actual pressure of ignition and a jet exhaust for propelling a power turbine, the fuel flow being provided to the burner through a fuel valve when the valve is in an open position, the power turbine having a rotatable turbine shaft adapted to fixedly engage a rotatable generator shaft, said generator shaft being connected to a generator, said generator shaft having an actual rotational speed, said method comprising the steps of:

• providing ignition of said fuel flow to produce said jet exhaust;
• generating said actual rotational speed in response to the presence of said jet exhaust;
• periodically measuring said actual pressure of ignition at successive intervals of time;
• periodically measuring the actual rotational speed at said successive intervals of time;
• calculating the rate of change in said actual pressure of ignition over a successive interval of time;
• calculating the rate of change in said actual rotational speed over said successive interval of time;
• comparing the magnitude of said rate of change in said actual pressure of ignition over said successive interval of time to the magnitude of a reference pressure rate of change value;
• comparing the magnitude of said rate of change in said actual rotational speed over said successive interval of time to the magnitude of a reference speed rate of change value;
• and
• closing said fuel valve in response to the magnitude of said reference pressure rate of change value being greater than the rate of change of said actual pressure of ignition over said successive interval of time, in the presence of the magnitude of said rate of change of actual rotational speed over said successive interval of time being less than the magnitude of said reference speed rate of change value;
• thereby stopping said fuel flow to said burner.

An engine control for detecting burner blowout in a gas turbine power plant of the type including a gas turbine engine having a burner receiving a fuel flow and compressed air, the burner for providing ignition of said fuel flow to produce an actual pressure of ignition and a jet exhaust driving a rotatable generator shaft, said gas turbine engine having a pressure sensor for providing a sensed pressure signal indicative of the actual pressure of ignition, the fuel flow being provided to the burner through a fuel valve when the valve is in an open position, the generator shaft being connected to a generator, the generator shaft having an actual rotational speed, and the power plant having a speed sensor for providing a sensed speed signal indicative of the actual rotational speed of said generator shaft in response to the presence of said jet exhaust;

• wherein said engine control comprises:
• memory means for storing a reference pressure rate of change signal and a reference speed rate of change signal;
• and
• signal processing means for storing a plurality of signals representative of a blowout detection algorithm, said signal processing means being responsive to said sensed speed signal and to said sensed pressure signal to provide
• a pressure derivative signal indicative of the rate of change in said sensed pressure signal over a successive interval of time;
• a speed derivative signal indicative of the rate of change in said sensed speed signal over said successive interval of time;
• and
• a command signal to said fuel valve closing said fuel valve in response to the magnitude of said reference pressure rate of change signal being greater than the magnitude of said pressure derivative signal in the presence of the magnitude of the speed derivative signal being less than the magnitude of said reference speed rate of change signal;
• thereby stopping said fuel flow to said burner.

An assembly for use with a generator, having a rotatable generator shaft, said generator for providing electrical energy in response to rotation of said generator shaft, wherein said assembly comprises:

• a power turbine, having a rotatable turbine shaft adapted to fixedly engage said generator shaft, and having a speed sensor for providing a sensed speed signal indicative of the actual rotational speed of said turbine shaft in response to the presence of a jet exhaust;
• a gas turbine engine, having a compressor for compressing inlet air to provide a compressed air stream, a burner for receiving a fuel flow and said compressed air stream and for providing ignition of said fuel flow to produce said jet exhaust, said gas turbine engine having a pressure sensor for providing a sensed pressure signal indicative of the actual pressure of said ignition;
• a fuel system, having a fuel valve for metering said fuel flow to said burner, said valve operating between an open and a closed position, said fuel system further including an actuator for controlling the position of said fuel valve in response to a command signal;
• and
• an engine control, having memory means for storing a reference pressure rate of change signal and a reference speed rate of change signal, and including signal processing means for storing a plurality of signals representative of a blowout detection algorithm, said signal processing means being responsive to said sensed speed signal and to said sensed pressure signal to provide:
• a pressure derivative signal indicative of the rate of change in said sensed pressure signal over a successive interval of time,
• a speed derivative signal indicative of the rate of change in said sensed speed signal over said successive interval of time, and
• said command signal to said actuator in response to the magnitude of said reference pressure rate of change signal being greater than the magnitude of said pressure derivative signal in the presence of the magnitude of said speed derivative signal being less than the magnitude of said reference speed rate of change signal;
• thereby causing said actuator to close said fuel valve and to stop said fuel flow to said burner.

A gas turbine power plant, of the type for providing electricity, wherein said gas turbine power plant comprises:

• a generator, having a rotatable generator shaft having an actual rotational speed, said generator shaft rotating in response to the presence of a jet exhaust, said generator for providing electrical energy in response to rotation of said generator shaft;
• a speed sensor for providing a sensed speed signal indicative of said actual rotational speed;
• a gas turbine engine, having a compressor for compressing inlet air to provide a compressed air stream, a burner for receiving a fuel flow and said compressed air stream and for providing ignition of said fuel flow to produce said jet exhaust, said gas turbine engine having a pressure sensor for providing a sensed pressure signal indicative of the actual pressure of ignition;
• a fuel system, having a fuel valve for metering said fuel flow to said burner, said valve operating between an open and a closed position, said fuel system further including an actuator for controlling the position of said fuel valve in response to a command signal;
• and
• an engine control, having memory means for storing a reference pressure rate of change signal and a reference speed rate of change signal, and including a signal processing means for storing a plurality of signals representative of a blowout detection algorithm, said signal processing means being responsive to said sensed speed signal and to said sensed pressure signal to provide:
• a pressure derivative signal indicative of the rate of change in said sensed pressure signal over a successive interval of time,
• a speed derivative signal indicative of the rate of change in said sensed speed signal over said successive interval of time, and
• said command signal to said actuator in response to the magnitude of said reference pressure rate of change signal being greater than the magnitude of said pressure derivative signal, in the presence of the magnitude of said speed derivative signal being less than the magnitude of said reference speed rate of change signal;
• thereby causing said actuator to close said fuel valve and to stop said fuel flow to said burner.