Influence of defect pressure on insulation characteristics of molded transformer model

This paper discusses the influence of pressure in a defect on time evolution of Partial discharge (PD) characteristics and lifetime characteristics of an insulation model of a molded transformer. Experimental results show that the time evolution of PD characteristics for a defect at atmospheric pressure is different from that for a defect at a reduced pressure. Secondly, the lifetime of a sample with an atmospheric pressure defect is short, since samples containing a defect at atmospheric pressure can lead to breakdown with a small amount of PD charge.