Transformer Oil Breakdown under Nanosecond Pulse

Abstract

The dielectric strength of transformer oil has been measured in the nanosecond regime under single pulse conditions. The dielectric strength of transformer oil with different DC breakdown field has been tested under nanosecond pulses. The results indicate that when the DC breakdown field of transformer oil increases the pulse breakdown field of transformer oil also increases, but the voltage rate of rise falls. The breakdown characteristics of transformer oil under pulses with different widths have been studied. The influence of electrode materials for transformer oil breakdown characteristics has been investigated. The breakdown voltage of transformer oil in aluminum electrodes is the lowest. The gap distances are ranged from 0.15mm to 1mm. The pulse generator provides less than 10 ns rise time and a 300kV peak amplitude voltage. The breakdown electric fields are measured by the umbrella probe and a 1GHz bandwidth oscillograph