Ratio correction or interposing CTs
Ratio correction or interposing CTs
(OP)
We are stuck with a situation where protection CTs (class 10P10, 10VA, 500/5) are used for metering - is this a problem?
The 500/5 amp ratio is too large for our current readings, we want use interposing/ratio correction CTs such that our metering is at 200/5 amp scale. What considerations do I have to follow to specify this ratio correction CT?
The 500/5 amp ratio is too large for our current readings, we want use interposing/ratio correction CTs such that our metering is at 200/5 amp scale. What considerations do I have to follow to specify this ratio correction CT?






RE: Ratio correction or interposing CTs
RE: Ratio correction or interposing CTs
RE: Ratio correction or interposing CTs
Hope this helps
RE: Ratio correction or interposing CTs
RE: Ratio correction or interposing CTs
RE: Ratio correction or interposing CTs
RE: Ratio correction or interposing CTs
ANSI/IEEE Std C57.13-1978 An American National Standard IEEE Standard Requirements for Instrument Transformers
RE: Ratio correction or interposing CTs
If you are in fact using programmable electronic metering, the CT ratio should not be a problem, as you would simply program the actual ratio. Perhaps you should consider replacing the metering rather than adding the interposing CTs, which will add complexity and further measuring errors to your circuit. If you are stuck with using analog metering, consider replacing the 5A full scale deflection meters (by the way, are we talking ammeters here or energy metering?) with meters scaled for 2A FSD.