Synchronizing Check Relay for Automatic Synchronizer?
Synchronizing Check Relay for Automatic Synchronizer?
(OP)
I'm looking at a Cumins Parallel Controller used in multiple Gensets.
One of the features included in the controller are:
• Automatic Synchronizer – Voltage and Phase Matching
• Permissive Synchronizing Check Relay
If you have an automatic synchronizer, why would you need the permissive Synchronizing Check Relay?
My thoughts would be a redundant system for backup protection in case the automatic synchronizer wasn't working correctly. Then you'd have the failsafe Check relay to prevent the generator from coming online during a nonsync event.
Just curious to know.
Thanks,
Maj
One of the features included in the controller are:
• Automatic Synchronizer – Voltage and Phase Matching
• Permissive Synchronizing Check Relay
If you have an automatic synchronizer, why would you need the permissive Synchronizing Check Relay?
My thoughts would be a redundant system for backup protection in case the automatic synchronizer wasn't working correctly. Then you'd have the failsafe Check relay to prevent the generator from coming online during a nonsync event.
Just curious to know.
Thanks,
Maj






RE: Synchronizing Check Relay for Automatic Synchronizer?
RE: Synchronizing Check Relay for Automatic Synchronizer?
1. As back-up of automatic synch.
2. Second for manual synch.
3. What we do, to autosynch we connect A-B phases to synch relay A-C or B-C. As Dave saied is really help in several bad cases, for example synch of generator via step-up trafo with voltage matching.
Regards.
Slava
RE: Synchronizing Check Relay for Automatic Synchronizer?
Excellent as always :)
RE: Synchronizing Check Relay for Automatic Synchronizer?
There were several problems to avoid, some being:
1) An interposing relay between the control panel and the switchgear, operated slower than expected (perhaps spomeone changed ir for a low speed operation device, rather than the high speed relay originally fitted), the synchronising occured later than expected.
2) Someone modified the panel and shorted out the synchronising close contacts. (Oh yes it happens!).
3) Someone tried to close the generator breaker locally, rather than via the synchroniser.
4) Remember, as we went from the 50's to the 60's, auto synchronisers were pretty advanced stuff! Manual synchronising, using three lights was the normal method.
5) Unless the relevant BS / IEC / ANSI specifications have changed dramatically, they call for the designer to cater for no worse than a three phase short across the generator terminals. A faulty synchronise can give forces many times higher than this.
So as we went to this new synchronising technology, the practice of fitting a check sychroniser across the breaker came in. This was a static device, with no control, just a "permit" window.
What seems to have happened, is that the auto synchroniser became more reliable, and cheaper, and often evolved into a two channnel device, each channel guarding the other, and the concept of a separate check synchroniser across the breaker was forgotten. Not in one of my power plants!
Just had a meeting last week with a lot of clever people (letters after their name - you know) I pointed to the site incomer breaker on the single line and said - is there a check synchroniser across this breaker? I got the usual "this is never going to go wrong, how could this happen? Is not this a maintenance issue?"
RE: Synchronizing Check Relay for Automatic Synchronizer?
Its right!!!! I totally agree with you.
For 6 big generators we bouth dual channel, full redandancy with additional synchrocheck option autosynch. device, but in all case in the last point we add static synchrocheck relay with additional logic, what check also autosynch, manual synchr command and all control status (no trips, dead bus situation, VT MCBs status, CB and disconnectors position, etc). And we connect it to another set of VTs. today price of synchrocheck relay is
Regards.
Slava
RE: Synchronizing Check Relay for Automatic Synchronizer?
I use Balser BE1-25 sync-check relays. I am so glad these are around these days, as they are not building smarter operators to run my generators.