Hi to all,

All sources that I checked are expressing the necessitiy of ferroresonance suppressing resistors connected paralelly to open-delta
secondaries of instrumentation VTs. But, I haven't find anything about
sizing calculation of this resistors, yet.

I found some application examples, let's say for a 34.5 kV system a 25 ohms, 600 Watts resistor connected parallely to an instrumentation VT. I guess, typical sizing values of resistors are like that, but how come, whati is the method?

Thanks in advance for all answers.

Moris

P.S. I'm not talking about high impedance grounding transformers which are also susceptible to ferroresonance phenomenon, I'm looking just for measurement VT application solution.

All sources that I checked are expressing the necessitiy of ferroresonance suppressing resistors connected paralelly to open-delta

I found some application examples, let's say for a 34.5 kV system a 25 ohms, 600 Watts resistor connected parallely to an instrumentation VT. I guess, typical sizing values of resistors are like that, but how come, whati is the method?

Thanks in advance for all answers.

Moris

P.S. I'm not talking about high impedance grounding transformers which are also susceptible to ferroresonance phenomenon, I'm looking just for measurement VT application solution.