An electrical authority requires for HV and MV energy meters that CT and VT are tested with primary current and voltage injection each four years.
Does any authority accept “online” or “live” calibration for CT and VT, and if such standards are developed by some certified body or lab?
This is...
In a 33 kV isolated industrial installation, there had been a trip from busbar residual voltage protection which opens the utility circuit breaker, leading to total blackout.
After busbar inspection nothing was found, so after reconnection from utility one feeder circuit breaker because of...
