Comparison of partial discharge activity in mineral oil and bio-degradable oil

This paper investigates the partial discharge activity and characteristics in mineral oil and bio-degradable oil. Both types of oils tested are commercial products and commonly used in transformers. Tests were done on laboratory models using paper insulated conductor sections to simulate transformer windings and needle-plane configuration to simulate corona in transformer. The laboratory models are insulated with both types of oils, with and without moisture. The overall partial discharge activity was analysed in terms of the phase resolved distribution. Also the individual partial discharge waveforms were analysed in the time and frequency domain.