Capacitor Bank Protection

dear,

when capacitors come in to circuit, harmonics also enter in to the supply lines. Depending upon the quality of the capacitors & installation - termination quality, harmonics are generated may be of the order of THD - 15% in the capacitor feeder.

Considering the above, safe value is 2 * In, where In is the total feeder current.

e.g. for 500 KVAR capacitors of 440V grades, In = 695 Amp.

So, Capacitor feeder breaker rating = 2*695 A = 1390A,

i.e. 1600A breaker as incomer.

Similar calculations for cables also, can be done.

1600 A breaker size is for the feeder which is conneting the capacitor bank to the Panel (Say PCC or MCC). OK

but another quary was "is there any effect of the I/C rating of PCC or MCC while capacitor bank is ON.

(Output KVAR) = (total connected kvar @ Vc) *(system vltg/capacitor vltg) ²

MCCB= ((output KVAR * 1000)/ ((supply vltg)*sqrt(3)))*1.5

Where Vc is the capacitor vltg

search cr4 for wiring size.......