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Gas Turbine Hazardous Gas Detector

GE Global Power Plant Systems Department

Zhenhai Power Generation

GT – 298516, 298517

MS9001FA

Hazardous Gas Detector

Detect hazardous concentrations of gas and immediately notify the operator of the situation so that the appropriate response can be taken.

1. Monitor the gas valve compartment and turbine compartment for the presence of natural gas.

2. Monitor the generator collector compartment and generator terminal enclosure for the presence of hydrogen.



DetectorsMonitor

Inside turbine compartment and fuel moduleMounted in PEECC(packaged electrical and electronic control center)


Detector housing

Splash Guard

Detector

Hazardous Gas DetectorWhen a new alarm is received, the digital LED display and one of the front panel status indicators (A1 or A2) will begin to flash. The flashing LED display will indicate either an actual alarm (gas detected) condition, or a malfunction “fault”. Fault conditions are indicated by one of the following codes, which will be shown on the flashing LED display.

F1 Open analog signalF2 Failed to complete calibrationF3 Software checksum errorF4 Sensor connections openF5 Not usedF6 Low supply voltageF7 EEPROM verification failureF8 Failed to complete setupF9 Calibration period exceeded

Hazardous Gas DetectorDESCRIPTION ALARM ACTIONS SETPOINT

HIGH ALARM A1 Supplemental (Follow –up) Actions VERIFY actual alarm condition PERFORM check to verify actual

hazardous condition Do not allow access to compartment

> 10% LEL

HIGH-HIGH ALARM A2 Supplemental (Follow –up) Actions

VERIFY actual alarm condition PERFORM check to verify

hazardous condition Do not allow access to compartment If level reaches 60% LEL, initiate a

manual shutdown of the turbine

> 25% LEL

Hazardous Gas Detector1 out 3 High – Alarm

2 out of 4 High-High –Alarm & Trip

High – Alarm

High-High –Alarm

High 7% LEL

High-High 17%

High 10% LEL

High-High 25%LEL –Lower Explosive Limit

Routine System Maintenance

Detectors

• The gas detection system requires periodic (weekly) inspection of the detectors. Inspect the detectors for lost dust sleeves and loose mounting.



Detectors

• System calibration should be done every 90 days, use a known calibration gas. Refer to the device summary for HI and HI-HI alarm values.

• If the sensor is installed where it may be subjected to dirty environment or adverse gases, more frequent calibration based severity of conditions is recommended.

• Refer to instruction manuals for calibration procedures.



Detectors

• A re-calibration should be performed if a detector has registered an alarm condition. Exposure of sensor to high concentration of gases can introduce stresses in the sensing element. Replace if necessary.

• It is recommended a log book be kept showing calibration dates and dates of sensor replacement.



Monitor

• Daily inspect Monitor panel for gas level readings and/or faults.

• Periodically (when detectors calibrations are checked) verify system functions.

• Annual – Clean modules; check power supply output voltages


Education

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