GT tripped with the Alarm of "Loss of Flame". Gt was started normally without any delay. After one month GT was tripped with the same FOut Alarm "Loss of Flame". Nothing abnormal was found this time again, and the following corrective action has been taken to avoid trip occurrence in future: (96CD) and (96FG) were calibrated, both Servo GCV (65GC) and SRV (90SR) were replaced, SRV/GCV manual stroke calibration was done with the feedback response of both LVDT.

Can anyone give advice about this trip and what action would be taken in future if happened again?

Thanks for all. My mail: foriqbal @ hotmail. com

 

Have you checked the cooling water lines and flowrate of cooling water to the flame scanners? Excessive cooling can cause condensation to build up on the lens during operation. Insufficent cooling can cause overheating of the scanner. Excessive leakage at the split line of the combustion section can also cause overheating of the flame scanners. A TIL was recently issued addressing some of these issues.

 

In our GT,s there is no Cooling water system in design and all the Flame scanners were cooled by natural air which was checked and found normal
( Flame scenner were remain cooled always)since the Loss of Flame trip happend after 30 days.
I Think Problem is somewhere else either Related in control Cards or malfucntioning of any field device.

 

Can you give more details about your turbine? I am looking for information such as:
* Model (5001A, 6001B, etc.)
* Fuel (gas, distillate, mix)

 

Generally speaking, water cooling is only used for flame detectors on units equipped with DLN combustion systems, though new standard combustor-equipped units might use water cooling for the Reuter-Stokes flame detectors if they are located in the turbine compartment instead of "outside" the turbine compartment in reliefs on the compartment enclosure walls.

 

Given below is the requested GT Model details...

Model: 5001 P-NT reference PG6371 (PA)
Speed/Frequency: 5120 RPM/50Hz
Air Flow: 440T/h with Natural Gas 10397nm3/h
design output 22 MW
MK-V (Simplex)

 

A copy of your Trip History Log would be useful to try to diagnose this one especially as you are running a Simplex machine. Any abnormality in the fuel control system could cause an immediate trip. You could try replacing both the TCQA & the TCQC cards in the <R> either together or one at a time if you can stand another trip.

Your main line of attack should be trip history to try and see what is happening first.

 

Try this and root cause of your problem will be identified:
1) Check for any diagnostic alarms in TCE1 card, such as TCE1 ground fault detected.
2) Run VIEW2 and check the output log, which will be showing you the status of assigned logic name (L28FDA etc.) with 1s sample rate. If you see alternating values of "0" and "1", you may have on base flame detector cable problem or the TCQC fault (unlikely).

Ali OZTAS