Voltage transformer signals for Synch check

[NickParker]

Should I compare the VT-C signal to the VT-A signal for sync check ? or VT-E in comparison to VT-A?
Similarly for VT-D to be compared with VT-B for sync check? or VT-F to be compared with VT-B?

Only at CB-C and CB-D locations it is possible to alter the speed/voltage using the speed/voltage adjustment selector switch?
Is there anything else that needs to be taken care of?

 

[waross]

First impression;
You are missing VTs at the DGs.
The DGs will not be able to sync to a live bus.
That may not be an issue.
It looks like a usable scheme.
As well as sync check, you may want to check phase rotation.
Sync check needs one VT on each side of the breaker.
Phase check needs at least two VTs at each side of the breaker.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[cranky108]

If the tie feeders are short, I would not bother with VT-c and VT-D, but attempt to sync the two buses.

 

[bacon4life]

I would have a sync check element for all circuit breakers that could be used to tie any two out of sync systems. This SEL aurora paper explains the details as to why. I have found it a bit easier to think of aurora mitigation as out-of-sync block rather than as sync check, as the settings may be significantly different. For example out-of-sync blocking for aurora mitigation may allow for 0.01 Hz difference and a 30 degree angle, whereas the sync check function that supervises the synchronizer function may have a setting of 0.1 Hz and a 10 degree angle.

Note that the sync check function is a different feature than a synchronizing function. The sync check relay only verifies that the frequency and phase angle differences are within acceptable limits. The synchronizing function actually adjusts the speed/voltage of the generator until an acceptable window occurs.