GE turbine frame 9E. Normal time taken from 0 to FSNL is about 15 min but now it took about 20 min. The delay starts at above 80% TNH. Below that speed the speed curve is normal. Please help.
Is this a one-time event or has it been occurring each time the turbine is being started?
Is the unit being started on gas- or distillate fuel?
Does the unit operate normally after breaker closure (that is, does it reach Base Load at its typical FSR value, or a higher or lower FSR value than normal)?
What did the exhaust temperature look like during the start-up? Was it excessively high, high enough to cause Exhaust Temp Control FSR (FSRT) to limit the fuel via the FSR Min. Value select function?
Did this start occurring after some kind of maintenance outage?
Does the turbine use a Mk IV- or Mk V SpeedTronic turbine control system?
Were there any Diagnostic Alarms annunciated during the "extended" start-up?
If the problem is not mechanical- or fuel-related, then something is preventing the fuel from being increased during start-up/acceleration. Monitor all the inputs to the FSR Min. Value select function to determine what is limiting the fuel during the period the turbine is accelerating slowly.
If you have a Mk V <I> or HMI you can trend/plot several values during start-up: TNHA, TNHAR, TNH, FSRACC, FSRSU, FSR.
