Geneartor not sychronizing Mark-V control system

We have turbine driven(Fuel gas ) generator frame-V machine and GE- mark-5 control system, the issue is Generator is not synchronizing after FSNL, can anybody explain what are the check points need to carried out for trouble shooting from Mark-5 control system?
 
We have turbine driven(Fuel gas ) generator frame-V machine and GE- mark-5 control system, the issue is Generator is not synchronizing after FSNL, can anybody explain what are the check points need to carried out for trouble shooting from Mark-5 control system?
You have to make sure that synchronizing permissifs are ok for a shot..like Voltage generator vs line matching, frequency line/generator matching...

Check the CSP file and also if you have markV studio check that synchro sequences are ok..
There are some signals and window synchro calculations in CSP file that need to be checked..

Also is that unit is /should be synhchronised to an infinite bus or grid facilities...

What is Line vs generator frequency/voltages..

James
 
We have turbine driven(Fuel gas ) generator frame-V machine and GE- mark-5 control system, the issue is Generator is not synchronizing after FSNL, can anybody explain what are the check points need to carried out for trouble shooting from Mark-5 control system?
As far as I know, synch is the same on all MKV control systems.
 

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shimat2,

There should be a synchronizing display on the operator interface (you didn't say if you were using an <I> (running IDOS) or a GE Mark V HMI (running MS-Windows and CIMPLICITY). On the synch display there should be a few little squares in a vertical line (it's usually on the left side of the display). Those little square are either red or green--and for an Automatic Synchronization to occur, all of the squares have to be green.

A VERY common problem for a lot of sites is that one or more of the Auxiliary AC motors are running when the unit reaches FSNL (Full Speed-No Load; rated speed)--and they should have shut off automatically. This includes the Aux L.O. Pump motor (88QA-1) and the Aux Hyd Pump motor (88HQ-1). Both of these must be OFF (not running) before an auto synch can be performed. So, if you have alarms that either or both pumps are running while the unit is at FSNL, then you have to stop them.

The best way to stop them is to send a person to the MCC (Motor Control Center) where the motor starters for the motors are located. Let's say the Aux Hyd Pump motor is running. Find the motor starter for 88HQ-1, and there will be an H-O-A (Hand-Off-Auto) switch on the door of the starter. Also have someone standing by at the Accessory Gauge Panel (usually in the Accessory Compartment). Everyone should have radios (walkie-talkies) and the Control Room should be listening to the conversation between everyone. Have the person in the MCC move the H-O-A switch on the 88HQ-1 motor starter to the OFF position and hold it there for a few seconds. The person in the Accessory Compartment at the gauge panel should be watching the hydraulic system pressure gauge. It should remain at its normal pressure (usually around 1500 psig), but it should not drop very much. If it drops quickly and shows no sign of increasing, the person at the gauge panel should tell the person in the MCC to release the switch and it should automatically return to the AUTO position. This would indicate there is some problem with the Main (Accessory Gear-driven) Hyd Pump which needs to be resolved.

If the Hyd System pressure remains high and normal, the person at the gauge panel can tell the person at the MCC to release the switch and it should automatically return to the AUTO position and the motor should remain in the OFF condition. If the motor re-starts, then there is something amiss with the motor starter circuit, the pressure switch monitoring the Hydraulic System pressure, or there's something wrong with the check valves or the Aux. Hyd. Pump or the relief valve, etc.

The person in the Control Room should be watching alarms, and and pump motor or system-related alarms (L.O. or Hyd.) should be broadcast to everyone.

If the system pressure remains normal, and the aux pump remains OFF after this test, then it should be possible to automatically synchronize the generator.

Finally, the synch selector on the Synch Display should be in AUTO.... kind of goes without saying.

These are the most common problems with a synch system that was working but suddenly stopped. If these arent' the problems, AND if work was recently done on the generator breaker or something related to the PT (Potential Transformer) signals or the permissives in the generator breaker close circuit. At this point, you need to get someone knowledgeable to site, if someone can't say, "Oh, yeah--we worked on those circuits and we need to check to make sure the wiring was restored correctly," and find and resolve the problem.

Please write back to let us know what you find and how you resolve the problem.
 
@shimat2,

  1. check if the unit reaches FSNL. if not refer to @CSA commands(L.O auxiliaries running feedback etc.l52qa)
  2. if the unit reaches FSNL check the exciter operation and make sure it is producing 11KV(some units Excitation will start at 14HM)
  3. in sync display, check its meet all the required parameters (between unit and grid)and no mismatch
  4. if everything ok and you are not able to close the breaker then you have to refer your site SLD for 52G or line breaker close permissive
  5. Check and make sure is the breaker has any rack in position feedback by Limit the switch and check the feedback.
  6. sometimes I see the operation team forgot to reset protection relays in the switchgear room, so kindly make sure everything is ok. and make sure the selector switch position is in AUTO.
  7. finally, if everything is ok still the problem exists then you need to provide SLD, alarm(include diagnostic alarm), and other details here. lots of senior people are here they can help only according to your details
 
shimat2,

You can attach a photo or a .pdf to threads/replies in Control.com.

Again, when something like this happens to a machine that was working, one should always ask: "What has changed?" Was some work done on the Generator Protection/Control panel? Was the generator breaker removed and reinstalled in its breaker cubicle (which means the secondary disconnects (the ones that pass the close signal to the breaker operating mechanism, and breaker status signals to the Mark V and other circuits) may not be making good contact. Often, when thinking about what work was done on the unit/machine/circuits one can think of something that may hot have been reassembled correctly or re-connected correctly.

A picture of the synchronizing display would be VERY helpful.

And, as vscontrol wrote, a list of active alarms would also be very helpful (you can take a picture of the alarm display).
 
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