The reason behind testing the tan delta at rated voltage or high voltage is the result can get effected due to partial discharge(if any)and will be actual value at rated voltage.But I agree that 11kv test is ok provided the trf does not have pds beyond limits.
Yes thanks scottf.Incidently meters manufactures here in India confirm that the meters are designed to withstand 10 times the rated current for 5 seconds. I do not know about static or microprocessor base meters i.e their capability of withstand high currents.We are trying to educate the...
144x-
It is not possible unfortunately to design the saturable core for very low VA of 1.2.For satuaration factor of even 10 it will not be possible to design the core without exceeding the errors limits.
Hence only alternative is to use the resistor or transducer. You may use few resistors of...
scottf
If 144x can provide the details of ratio,accuracy, rated and actual burden and STC level,rated voltage etc practical solution can be worked out with saturable reactor.
1)The error of the CT if .2 class can swing betwwen +0.2% to -0.2% at rated current with variation of VA from 0.00 to...
144x
1)The core for metering porpose should saturate if the fault current exceeds predetermined value(Instrument Security Factor- IEC Standards).This factor may be 5 or 10.
You may use the saturable core across the secondary winding which will draw negligible current at rated overloaded current...
