we are facing a problem with our MarkV simplest turbine that whenever we synchronise the machine, we receive L86S Auto Sync lock out alarm.

please help.

Regards,
[email protected]

 

Does the unit synchronize and then the auto-sych lockout is annunciated, or is it not possible to auto-synch the unit and it must then be synched manually?

How has this problem existed? What happened just before this problem started? Was there a maintenance outage or some kind of sequencing or Control Constant modification made?

 

Yes, the alarm appears after the unit is sychronized. There is no problem for synchronization, only alarm persists after sync. This problem started after Excitation system revamping work.

Thanks.

 

You should most likely consult with the company who performed the excitation revamp to discuss what changes were made which have this effect on the operation of the unit.

I've seen this problem before when breaker closure does not automatically cancel the AutoSynch command. Do you have to manually de-select AutoSynch after breaker closure?

Can you clear the alarm after AutoSynch is de-selected after breaker closure with a Master Reset?

 

Dear CSA,

We are also facing of problem L86S auto sync lockout during auto synchronization in GTG-1 When we are selecting manual sync and master reset. It is resetting.

During auto sync selection, L86S is appearing and auto sync is not happening. We are doing master reset, after that auto sync is happening. L86S is coming from L83AS frozen contact. I could not understand problem of L86S is coming.

Time delay of auto sync lock out is 0.5 Sec.

In GTG-2, Auto sync is happening with same logic and same time delay.

Kindly guide.

 

When did this problem start? After a maintenance outage? After the generator breaker was racked-out/racked-in? Was some other work done on the generator breaker--or the synch circuit wiring terminated in the Speedtronic turbine control panel?

What other alarms (Process- and Diagnostic) are present?

You didn't say what version of Speedtronic the machines use.

If it's Mark V, then the Alarm means the 25 (Auto Synch) relay does not seem to be operating--<b>OR</b>, more likely the breaker close circuit is open and even though the Auto Synch relay is being told to close there is no voltage from the breaker close circuit to the TCTG card to operate the relay. There may be another contact/permissive in the gen breaker close circuit that is not closed. Or, the secondary disconnects of the generator breaker may not be fully engaged.

Refer to the Synchronizing Circuit drawing of the Signal Flow Diagram of Appendix D of the Mark V Application Manual (HEH-6195) for details of the 25P, 25X and 25 relay circuit.

Can the breaker be closed with Manual Synchronization selected? If not--and there are no other related Process- and/or Diagnostic Alarms present, it's most likely a problem with the breaker close circuit.

Please write back to let us know how you fare--and what Speedtronic the units use.
(If it's Mark VI, refer to the TTUR, card, of the VTUR (if I recall correctly) in the Mark VI System Guide (usually Volume II), for synch circuit and generator breaker close circuit details.)

The more information you provide in your original post, the better and more concise our responses will likely be. The control.com only lets you select Mark V/Mark VI, and there's Mark IV, Mark V, Mark VI and Mark VIe. And while sometimes the differences are few, sometimes there is little or no similarity. Help us help you by providing as much information as possible in the original post.

Hope this helps!