Hello,

What are the immediate steps a control engineer needs to perform after a GAS TURBINE TRIP (Mark V)? What are the basic troubleshooting tips?

 

Hello,

The absolute first thing to do is make sure there is a hard (paper) copy of the Process Alarms which occurred before and after the trip. The Trip History display should also be printed for review. The Trip History has the 64 alarms before the trip occurred and the alarms for a few seconds after the trip as well as some operating data. I believe the Trip History Display is documented in the Mark V Operators Manual, GEH-5979 (even if the operator interface is a GE Mark V HMI the Operator's Manual still has relevant information about the Trip History Display).

Because the GE standard is that any condition which trips the turbine must have a Process Alarm to go with it to be able to say exactly what caused the trip. The problem with GE is that when a turbine is tripped many times other trip conditions are detected after the original cause of the trip--and they are <b>NOT</b> blocked from being displayed or printed. This leads to much confusion about what the actual cause of the trip was when there are two or more trip alarm messages.

It shouldn't cause confusion--but it does. Because the first alarm trip message <b>chronologically</b> is <b>THE</b> cause of the trip. So all that needs be done is review the alarm printout to find the oldest trip message and that's the cause of the trip.

If the original trip is 'LOSS OF FLAME - TRIP' that means that flame was lost BEFORE any condition that would trip the turbine was detected. That means fuel flow was insufficient to maintain flame. That could be because the stop valve closed prematurely (failure of solenoid; loss of trip oil pressure; low fuel supply pressure or low fuel supply flow-rate; etc.). A 'Loss of Flame -Trip' from load usually is preceded by a fast reduction in load.

But, generally trips are usually preceded by some (alarm) warning that a trip is impending, that wasn't heeded or was overlooked. Sometimes several Diagnostic Alarms can be the warning, though Diagnostic Alarms do not cause the trip.

If you want help, you will need to provide a LOT more information about the type of Mark V, the fuel being burned, the alarms (Process & Diagnostic) BEFORE the trip, and the alarms annunciated at the time of the trip as well as for 15-30 seconds after the trip. Also, please provide the battery voltage readings with respect to ground as measured with a voltmeter between the <PD> PTB1-1 and ground, and <PD> PTB1-3 and ground.

GE-design heavy duty gas turbines never just trip without an alarm--the 'Loss of Flame - Trip' alarm ensures that doesn't happen. SIFT (Software-Implemented Fault Tolerance) on a TMR Mark V won't let that happen--on a properly-configured, well-maintained Mark V.

There might be a Mark V Process Alarm that reads "GAS TURBINE TRIP" but I strongly suspect that message came from a DCS or other control system--not a Mark V. The Mark V could be driving a discrete (contact) output to a DCS or other control system that results in that message, but it would be the result of something specific which would be logged to the printer and to the Trip History Display.

Please write back with more information and details.

 

Hello,

Thank you for your detailed reply CSA. I was asking a GENERAL question about 'gas turbine tripping' caused by ANYTHING. What are the immediate steps an engineer needs to do after gas turbine trip for any reason. What I get from your reply is that after a trip, an engineer should immediately:

1) get hard copy of the process alarms
2) save trip history record

What other measures should be taken apart from the above mentioned if i got it right.

Thanks!