CT Internal Resistance
CT Internal Resistance
(OP)
Gents,
good morning/evening. We are in the process of specifying CTs for a 22 kV 50 Hz switchboard protection system (Incomers, feeders and bus-zones) and are trying to validate the calcs for CT ratios, burdens etc.
We were using the ABB publication:
Calculation of the Current Transformer Accuracy Limit Factor
but have come up against the need to know the internal resistances of the CTs. Can anyone suggest an easy method to evaluate short of asking the manufacturer?
Any guidance is welcome, thanks and Happy New Year.
good morning/evening. We are in the process of specifying CTs for a 22 kV 50 Hz switchboard protection system (Incomers, feeders and bus-zones) and are trying to validate the calcs for CT ratios, burdens etc.
We were using the ABB publication:
Calculation of the Current Transformer Accuracy Limit Factor
but have come up against the need to know the internal resistances of the CTs. Can anyone suggest an easy method to evaluate short of asking the manufacturer?
Any guidance is welcome, thanks and Happy New Year.






RE: CT Internal Resistance
RE: CT Internal Resistance
at the moment our local guys are on leave. We are hoping for something sooner.
RE: CT Internal Resistance
RE: CT Internal Resistance
This will be an order of magnitude value only.
If you search the SEL website, you will find several white papers by Stan Zocholl regarding CT performance in switchgear.
David Castor
www.cvoes.com
RE: CT Internal Resistance