Gas turbine fire detection system including cooling system upstream of aspirating smoke detector, and related method

A fire detection system for a gas turbine system including a plurality of fire risk zones, the fire detection system comprising:

• a pipe intake port proximate to each of the plurality of fire risk zones within an enclosure surrounding the gas turbine system;
• at least one manifold in fluid communication with at least one of the pipe intake ports;
• a first temperature sensor positioned in each manifold;
• a cooling system downstream of the first temperature sensor in each manifold, the cooling system configured to reduce a temperature of a gas flow in a respective manifold;
• a valve in each manifold upstream of a respective cooling system;
• an aspirating smoke detector downstream of the cooling system in each manifold, the aspirating smoke detector configured to draw a respective gas flow through a respective manifold and detect smoke in the respective gas flow;
• and
• a controller in communication with each first temperature sensor and the aspirating smoke detector, the controller configured to generate one of:
• a) a first alarm in response to any first temperature sensor detecting a temperature of the gas flow exceeding a first temperature threshold, and b) a second alarm in response to any aspirating smoke detector detecting smoke in the respective gas flow;
• and
• wherein the controller is further configured to close a respective valve and to shut off the aspirating smoke detector in response to the second temperature sensor detecting the temperature of the gas flow in the respective manifold exceeding a second temperature threshold.

A method of fire detection for a gas turbine system including a plurality of fire risk zones, the method comprising:

• generating a gas flow in a manifold from at least one of the plurality of fire risk zones using an aspirating smoke detector;
• generating a first alarm in response to a first temperature sensor in the manifold detecting a temperature of the gas flow exceeding a first temperature threshold;
• cooling the gas flow downstream of the first temperature sensor and upstream of the aspirating smoke detector using a cooling system;
• and
• generating a second alarm in response to the aspirating smoke detector detecting smoke in the gas flow.