Partial discharge patterns for silicone rubber insulators under salt-fog

The paper presents an investigation on the use of partial discharge (PD) as a means to study the development of leakage current (LC) on silicone rubber insulators in a salt-fog chamber. Simultaneous measurements of low-level LC and PD on dead-end type silicone rubber insulators are performed. Signal processing techniques are then applied to the recorded PD data, features such as the maximum and mean charge of the PD pulses are extracted, and the PD trends are obtained using the moving average technique. The results show that PD is a sensitive method for detecting the transition from corona from water droplets to dry-band arcing and an alternative to study the early ageing stage of silicone rubber insulators.