Medium Voltage Capacitor Nameplate Data

[wirenut1980]

Hello, A serviceman today measured the capacitance of one of our distribution capacitors to see if it might be faulty. The capacitor is made by Cooper and is 7,200 V single phase with three of them hooked up in a wye configuration. This particular one is a 150 kVAR unit. The capacitance reading came out to be 7.89 uF. I calculate the resulting reactive power to be 154.2 kVAR. So it seems the capacitor is in good shape. My question is about the nameplate data on the capacitor.

The name plate reads: CRDT:7.67 uf

CACT:7.91 uf

DEV: +3

S/P 3/3

Anyone have any idea what this all means? Apparently we do not get any literature from Cooper with these things. I also tried looking on their website for a manual, but all I could find were catalog information which did not help. Thanks!

 

[steve66]

A wild guess:

Crdt is the design value, or the capactiance they attempted to make.

Cact is the actual value of the capactior (what it tested at when it left the factory).


The Cact is about 3% higher than Crdt. That might be the "Dev".

Steve

 

[wirenut1980]

Good guess!...Thanks!