We have SOLAR Taurus 60 Gas turbine generator in our plant. We are facing problem with turbine start up. During start up sequence after cranking when ignition happened 'Flame out on Low Engine Temperature T5 alarm comes and machine tripped. We have carried out following checks:
1) Gas path thoroughly checked for any blockage. Found cleaned.
2) Primary fuel gas valve, secondary fuel gas valve and FGMV functionality checked and found normal.
3) Air intake filters replaced with new one and IGV opening confirmed to its minimum position.
4) All T5 temperatures found normal.
5) Spark plug checked and found normal.
6) Bleed valve also in correct position.
After all these still machine is tripping in 'Flame out in low temp T5'.
Can anyone help to resolve this issue?
Low engine temp and loss of flame would indicate insufficient fuel flow to maintain flame.
Dirty inlet filters would do the opposite--result in higher than normal engine temperatures.
I'm not familiar with the control system for the Solar units, but if it monitors fuel flow-rates then you should be able to compare readings from a trip to a good start-up.
As with all troubleshooting of problems that just started recently one must think back to what has changed since the problem started. Did it start after a trip from load? Or after a maintenance outage? If it was after a maintenance outage, what was done during the outage that might have affected the fuel flow-rate?
Does the gas fuel supply piping have any kind of filters (coalescing?) If so, have the filters been checked? Is there a y-strainer upstream of the stop valve, and if so has it been checked for cleanliness? (Differential pressure gauges can be misleading, especially if the filters for so dirty they ruptured. Also, many times the valves on differential pressure gauges are not adjusted correctly. Differential pressure switches can rupture and not give proper readings.)
Finally, some sites can be in a location on the gas supply pipeline where they can get a big slug of air after pipeline maintenance that will take a long time to get rid of just through failed start attempts. Use a hazardous has detector to check a vent close to the stop valve to be sure that gas fuel is all the way up to the stop valve.
And please write back to let us know what you discover. Often times people are distrustful of control systems when they are really correct. This could likely be one of those times.
Best of luck--and write back with your findings!
Thank Your CSA for your valuable suggestions.
Yes, you are correct we changed Fuel gas control valve (Electrically actuated) which is same in model and part number. But during trend analysis it is found that the time taken to reach light off sequence from ignition is few secs more than the other Turbines. The firing temp was also very low. Though its a new valve, we have a doubt in the valve itself as we have carried out all other inspection before and nothing significant problem found in other part of Turbine.
We called Solar Vendor and service engineer disclose that the new valve have some valve characteristic issues, and they have attended similar problem elsewhere. They have changed the minimum opening of valve to 1% more from the existing, in steps of 0.2%.
Now The Turbine is running smooth.
Thank You for your support.
I presume you have an electronic fuel valve. One of fuel control modes that Solar had was "PCD_dP" control. This was used as one of the protections of over fueling the engine in case of flameout. You might want to look at the calibration of the PCD transmitter in case it is giving you issues.
Thank You DJMBA for your feedback.
We have checked PCD transmitter and found OK. The problem we found with FGMV (Fuel gas metering valve). Its characteristics are different from the old as we have replaced the same with new one. Vendor changed the minimum opening and problem resolved.
Thanks for your support.