Partial discharge characteristics of thermally aged mineral oil and eco-friendly vegetable oil under uniform electric field

Partial discharge (PD) detection plays an important role in the life assessment of liquid insulation in transformers. This paper investigates on the PD activity and characteristics in thermally aged mineral oil and eco-friendly rice bran and Sesame oils. To simulate surface discharges, plane-plane electrode configuration with pressboard of 1mm and 3mm thickness was used. The phase resolved PD patterns of thermally aged rice bran oil, sesame oil and mineral oil with pressboard were recorded and analyzed. From the results it is observed that the inception voltage of eco-friendly vegetable oils is higher than mineral oil. Also vegetable oil shows better PD characteristics hence they can be used for high voltage insulation applications.