Influence of partial discharges on void gas pressure

The development of void gas pressure has been measured at different levels of voltage and thermal stress. The void gas pressure typically exhibits a fluctuating behaviour in the beginning of ageing and then subsequently decreases at a constant rate that increases for increasing voltage stress. It is larger at 50°C than at room temperature. A characteristic pd-pattern was observed to develop after a certain ageing time dependent on the temperature level. The characteristic pd-pattern could to some extent be explained as an effect of indirect interaction