Circuit Breakers for Generators - Islanded Generation

[NickParker]

Is it okay to apply the normal circuit breaker instead of GCB's provided the delaying of circuit breaker tripping time?
What are the pro's and con's of doing this?
If done, what are the possible issues to be taken care of?

 

[crshears]

I'm not sure I understand the question . . .

What's your objective? Are you trying to avoid the added expense of using GCBs rated for 2PU withstand voltage across open contacts?

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[bacon4life]

I saw one case of regular distribution class breakers instead of GCBs being used. The distribution class breakers met all the electrical parameters, but they mechanically wore out within a few years. The generators at this plant were started/stopped much more often than a typical distribution circuit is opened.

 

[FreddyNurk]

ScottyUK has some pretty emphatic opinions on doing this sort of thing.

Not something I'd advocate for at 11kV either. I'm presuming that you're looking at delaying the opening time to avoid rating the switchgear for prospective fault currents as a result of proximity to the generators?

EDMS Australia

 

[RRaghunath]

Delaying the circuit breaker opening when there is a fault, I don't think it is a good idea.
I think you can use standard distribution CBs provided DC component interrupting capability is met. For this purpose, you may have to choose a higher Ampere rating than that required by the rated generator current.
It is the DC component interrupting capability that differentiates the Generator CB from standard distribution CB.