Frame 5 GT flameout at 81% TNH

J

Thread Starter

JJss

Dear All

After CI, Frame 6 GT Mark V simple Cycle, flame out occurred and tripped the unit at FSNL. Activities carried out during CI

1.Duel fuel nozzle replaced

2.Liner & TP replaced

3.Cross fire tube replaced

4. SRV & GCV serviced

Observations:-
first flame out happened Can # 7 at 81% TNH
Second flame out happened Can # 3 at 99% TNH
Third flame out happened Can # 2 at FSNL
FPG2 pressure was OK all the time (at FSNL 16.5 Bar)
GCV opening was OK
IGV opening was OK
Gas flow disturbance not found.

Kindly advice what to do?
 
Which are the alarms?

If the alarm is "Lost of flame", please read the working range of temperature into the specification letter of the flame detectors and make a measurement of the flame detectors temperature before the trip. It is possible that you have a hot gas leak and this is transmitting a high temperature to the flame detectors, that is higher than the maximum working temperature of them according to flame detector specification. That will cause a trip through the malfunction of the flame detectors. Verify also the compartment cooling fan motor (88BA, 88BT or some like that)

Best regards,
Mark
 
Can you expand on "GCV & SRV serviced"? What other alarms did you get? Have you tried again since this failure? I would suggest a re-calibration of the SRV and GCV again and a check on the Start up FSR settings. If you know how, run a VIEW plot next start up as well.

Good Luck
 
glenmorangie is spot on--<b><i>based on the information provided</b></i> the most likely culprit is GCV LVDT calibration, or IGV LVDT calibration.

The title of the thread says the unit (a Frame 5) is tripping at 81% speed, which is about when variable IGVs start to move open from 34 DGA to 57 DGA. Which means the air flow through the machine starts to increase pretty quickly. If the fuel/air mixture is very lean when the IGVs open then flame could be extinguished--which would result in a "Loss of Flame" trip.

The body of the thread says the unit is a Frame 6 (Model B is presumed) and that the unit flames out when it reaches FSNL (100% speed). So, it's not really clear when the unit is tripping--and, also, as siem noted--the original poster did not provide the alarms from just before to just after the trip occurred.

If the gas valves were refurbished/repaired, then it's also a safe bet that the servo-valves were removed and reinstalled, or possibly that new servo-valves were installed as part of the refurbishment. If so, then was the polarity of the servo current to each of the servo coils verified before attempting a unit START?

But, there's not enough information--and there is conflicting information. To be of help, we need more, better, non-conflicting information.

By virtue of the fact that the original poster mentioned four flame detectors, it is presumed this unit has DLN-I combustors--but that's just a guess.
 
> glenmorangie is spot on--<b><i>based on the information provided </b></i> the most
> likely culprit is GCV LVDT calibration, or IGV LVDT calibration.
>
> What about DLN combustion characteristic change.

change in those parts (combustion) will affect the tuning variables for that particular setup.

Looking forward to thoughts...
 
Dear JJss

To complete what CSA has said <b>Conflicting information</b>: CI means Combustion Inspection but on the thread description, the CI has been extended to Liners and Transition Pieces (TP). So if, at origin, it was a CI, Why did you extend it to TP? And Did you checked/replaced the flame detectors during this Inspection?

About ambient conditions how much relative humidity is? Because high humidity combined with lean fuel gas will extinguish your flame.

Regards
Karim
 
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