Abstract
This paper describes the method of improving the interfacial region between the insulation and the semiconducting layer by using an additive. This method provides the diffusion layer of an additive at the interface. Several kinds of nonionic surfactant which were various in molecular weight distribution and HLB value were selected as additives.
The additive concentration in the insulation was measured with FT-IR having micro-beam accessory. To investigate the effect of additives on ac and impulse breakdown strengths were measured and additve content profiles in the insulation were quantitatively analyzed.
The dielectric breakdown strength at 1% Weibull breakdown probability is improved about 2.3 times in AC and about 1.2 times in impulse breakdown strength than that of the conventional materials. An additive which improves the ac breakdown strength also improves the impulse breakdown strength.
The concentration profile is affected by the kind of additive. There exists a close correlation between the weight concentration of additives and the breakdown strengths. Both AC and impulse breakdown strengths increase as the weight concentration of additives diffused in the insulation near the interface increases up to about 1%.
