Study on Accumulation Effect of Multiple Lightning Impulse on Vegetable Oil-Paper Insulation

Vegetable insulation oil has been widely used as a good liquid dielectric for oil-paper insulation power equipment. During the operational life, the oil-paper insulation power equipment can suffer from hundreds of lightning impulse, which cause insulation damage. Thus, study on the accumulation effect of multiple lightning impulse on vegetable oil-paper insulation is significance. However, few literature studies on the impact of lightning impulse accumulation on vegetable oil-paper insulation. In this paper, the accumulation effects of multiple lightning impulse on vegetable oil-paper insulation are studied. The Voltage-Number (V-N) characteristics and two-parameter Weibull distribution are used to evaluate the insulation performance of rapeseed oil-paper insulation and calculate the cumulative failure probability. The dielectric properties of the oil-impregnated insulating paper were measured to analyze the insulation damage and deterioration. Results shows that dielectric constant, dielectric loss factor and volume resistivity increases with increasing cumulative number of lightning impulses.