Breakdown Characteristics of Oil Impregnated Insulation Paper with Different Ageing Condition under the Composite Electric Field

There are many researches about the effect of oil/paper proportion, testing temperature, AC/DC ratio and other effects on the breakdown characteristics of oil-paper insulation under the composite electric field. However, the breakdown characteristics of oil-paper insulation under the composite electric field in the process of ageing are rarely reported. In this paper, the breakdown characteristics of the oil impregnated insulation paper with different ageing condition under the composite electric field were investigated. Results show that there is no necessary link between the breakdown characteristics and the ageing degree of oil-paper insulation. The breakdown voltage value decreased with the rise of the AC component under the composite electric field. The breakdown voltage with aged paper changed by new paper is slightly higher than that of the aged oil being changed by new oil.