Switching Surge Testing of Transformers

In this paper, the authors discuss the desirability of introducing a switching surge test on transformers having system voltages 400 kV and above. A practical method for executing such tests is described, one which utilizes impulse-voltage testing techniques. This method is illustrated by test results from transformers. It is shown that the duration of the surges can be extended by making use of flux reversal in the core. Also, a method for calculating obtainable waveforms is given, and proposals are made on the characteristics of a standard waveform.