Laboratory investigation of treated coconut oil as transformer liquid insulation

This paper presents laboratory investigation of treated coconut oil as alternative to liquid insulation of power transformers. Thirteen different virgin and treated coconut oil samples consisting three different brands were used for the investigation. Frequency Dielectric Spectroscopy measurements were conducted on the samples at room temperature and at high temperature of 65°C. The conductivity, loss tangent, permittivity and the activation energy were calculated and used for the analysis. It was found that the conductivity improved slightly with heat treatment and neutralization process. However, during one week ageing, the conductivity improved significantly. It suggested that with proper treatment, coconut oil can be used as alternative transformer liquid insulation.