Dielectric Characteristics of Turn-to-Turn Insulation Models of Gas-Insulated Transformer under Very Fast Transient Voltages

Abstract

This paper deals with the partial discharge inception voltage (PDIV) and breakdown voltage (BDV) characteristics of turn-to-turn insulation models for SF₆ gas-insulated transformers under steep front short pulse voltages, of which waveforms are 35/65 ns and 50/370 ns. It was found out that PDIV under nano-second pulses were 1.05_??_1.15 times higher than those under standard impulse voltages and BDV under nano-second pulses were about 1.4 times higher than those under standard impulse voltages. The ratio of impulse PDIV to ac PDIV is 1.40_??_1.48 for standard impulse voltages and 1.32_??_1.37 for switching impulses.