What is through fault in power system?

Answer: A through fault is one which is beyond the protective zone of the equipment but is fed through it is called through fault.
Try to explain with an example, suppose a fault occur at a feeder that is fed by a transformer now because of fault in the feeder heavy current flow through the Transformer although there was not any problem in transformer. This is the reason that we called it through fault.
I hope that you understand it.

You are welcome to read more Important Interview Questions and MCQs.