抄録
It is already known that partial discharges in a void in insulating materials and between a polymer and a conductor, may lead to degradation of insulating materials, and finally to breakdown of the insulation system. The occurrence of the partial discharge depends on a shape of void and atmospheric condition. The object of this work is to investigate the degradation process of polymeric materials under various humidities in a void.
The characteristics of the gaseous discharge products were analyzed by Fourier Transform Infra-Red Absorption Spectroscopy during the discharge condition. At the same time, the discharge magnitude distribution was measured by a special internal discharge pulse measurement system which could analyze the discharge magnitude according to the phase angle area of the applied voltage. The effect of water on the degradation of insulating materials in void exposed to partial discharge has been investigated by the FT-IR analysis and the measurement of the discharge magnitude distribution in each phase area.
As a results, the time to breakdown for 50% humidity is shorter than at that low and high humidity conditions. The time dependency of carbon dioxide differs from the case of humidity. Carbonyl group increases, and end vinyl group decreases with the discharge deterioration time. Moreover, the discharge magnitude in all phases at 50% humidity is greater than at that low and high humidity condition.
