I agree to above point. Specific synchronization eqquipment is normally required to synchronize groups of generators across bus-couplers circuit breakers, since the generators set notmally allows synchronizing across the generator circuit breaker only.

Is "bus-tie breaker" just a different name to "bus-coupler circuit breaker" or they are different?

Aikhh,

My understanding is that you have 2 busses : one at 415 V fed by 12 generators, each of them 1.5 MVA and a second bus at 3300 V, fed by 4 generators, each of them 1 MVA. You try to interconnect these 2 busses via a 1.5 MVA 3300/415V transformer (and at least 2 breakers: bus1 - transformer in and bus2 - transformer out). If one of the generators has to be taken off-line, the power it delivered to its bus shall be compensated from a power influx from the other bus (via transformer).

To synchronize 2 busses implies the same voltage, frequency and in-phase.

If the 2 busses are operational (hot) they might have the same frequency and the same voltage (via transformer and generator voltage regulators), but there may be a phase (time) difference and the synchronization process can be rough, especially if the difference at that moment happens to be 180 deg (max). Usually that difference is eliminated by slightly modifying the frequency.

As I see it, you may have one of the busses hot (all contributing generators are in parallel and feeding that bus) but to synchronize the second bus you would have to start the other generators one at a time ( each of them has to be synchronized individually) till all are connected in parallel to bus 2 (which is connected in parallel to bus 1 via transformer)

The synchronization procedure is basically the one described in MS response.

The regulation of the power flow between the 2 busses has also to be addressed, since there is a limitation at 1.5 MVA (the proposed transformer).

Yes. You can synchronize the system.

dhayanandhan.s,

india.