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A two shaft gas turbine drives gas compressor equipped with Speedtronic markII control system experiencing a high exhaust temperature after after complete sequence and during manual raise command for increase NHP so that the exhaust temperature increases rapidly and the high pressure speed can't reach 95% of unit rated speed,which is 11140, due to Temp. Fuel
The unit is not equipped with inlet guide vane, there is only one bleed valve.
Before the new conditions take place, The unit was running at rated speed 7 full loaded with relatively high exhaust temperature about 525 0C, ALARM SET POINT IS 540 0C before cleaning axial compressor
so a clean for axial compressor was done but the result was negative and the unit condition became worst than before, as described earlier and couldn't reach rated speed due to temperature limit.
It was observed during a start up trial that intrvalve pressure, P2,down stream pressure of SRV exceeds 10.5 bar to reach 15 bar while fuel gas pressure down stream gas control valve, gcv, reaches 6 bar
The following were checked and replaced where necessary:
- Air inlet filters
- fuel gas transmitter, 96FG
- comp. discharge press. transmitter 96CD
- Servovalves for speed/ratio & gas control valves
- LVDT'S for SRV & GCV
- Bleed valve
- speed sensor 77HC
- fuel gas valve's trim (plug & seat)was inspected
nothing abnormal is found, null bias of servo valves are ok, (0.2-0.6)
LVDT feed back (0.74 min- 3.25max)are ok
No positive result has been giving and still in the same condition of high exhaust temp.
would you please help what the problem could be?
The unit is not equipped with inlet guide vane, there is only one bleed valve.
Before the new conditions take place, The unit was running at rated speed 7 full loaded with relatively high exhaust temperature about 525 0C, ALARM SET POINT IS 540 0C before cleaning axial compressor
so a clean for axial compressor was done but the result was negative and the unit condition became worst than before, as described earlier and couldn't reach rated speed due to temperature limit.
It was observed during a start up trial that intrvalve pressure, P2,down stream pressure of SRV exceeds 10.5 bar to reach 15 bar while fuel gas pressure down stream gas control valve, gcv, reaches 6 bar
The following were checked and replaced where necessary:
- Air inlet filters
- fuel gas transmitter, 96FG
- comp. discharge press. transmitter 96CD
- Servovalves for speed/ratio & gas control valves
- LVDT'S for SRV & GCV
- Bleed valve
- speed sensor 77HC
- fuel gas valve's trim (plug & seat)was inspected
nothing abnormal is found, null bias of servo valves are ok, (0.2-0.6)
LVDT feed back (0.74 min- 3.25max)are ok
No positive result has been giving and still in the same condition of high exhaust temp.
would you please help what the problem could be?