The vital role of transformers in the power system is well known: they transfer electrical energy from one electrical circuit to another and typically, during this process, change the voltage of the electricity flowing in the circuit in a predetermined way....

Since the 1980s, Very Low Frequency (VLF) testing of cables, in which the tested cable must withstand an over rated AC voltage for a specified testing time without flashover, has been accepted as a way of significantly improving system reliability by...