Switchgear information

[HienN]

Dear all,

In one switchgear manual that written:

1. Out-of-phase current switching capability
2. Out-of-phase Synchronizing

What do they mean? Does it imply that the switchgear is used for Power Generator?

If I turn on the switchgear with out-of-phase current? 3.What will happen to the Generator?

Thanks

Regards,

HienN

 

[ScottyUK]

1 & 2: possibly for generator service, but could also be on the transmission system. It is difficult to say for sure with only a fragment of the information.

3. Bad things, or sometimes very bad things. Possibly "buy a new generator" bad. Anything from winding movement to bits of generator and turbine scattered across the neighbourhood.


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If we learn from our mistakes I'm getting a great education!

 

[Kiribanda]

HienN,

Any generator circuit breaker should be given the rating "OUT OF PHASE SWITCHING CAPABILITY".Because a generator can go off line due to (a)out of step (b)wrong synchronizing.Therefore,both (1) & (2) refers to the same rating.

Therefore,if the subject breaker is used for generator switching, then per ANSI/IEC "OUT OF PHASE SWITCHING CAPABILITY" should be given on the name plate.Per ANSI that rating corresponds to 90 degree out of phase switching at rated maximum voltage.Per IEC it is at 120 degree.(This is not normally applicable to general purpose circuit breakers which are designed for X/R=17 unless specification calls for that rating).