Statistical Analysis on AC Breakdown Voltage of CNT Nanofluid with Mineral Oil and Palm Oil

Nanofluids can be regarded as next-generation heat transfer fluid that has enormous potential to enhance the performance of insulating oil in the transformer. In this study, the breakdown voltage of new colloidal mineral insulation oil and natural ester oil (palm oil) was systematically investigated and compared. Carbon nanotubes (CNT) nanofluid is formulated by dispersing CNTs in mineral and palm oil. The AC breakdown voltage test is performed accordingly to the methods and precautionary steps based on IEC 60156. For a successful forecast, instead of referring to the average and lowest possible breakdown failure data, there are few types of distributions (Weibull, normal, Gumbel and generalized extreme value (GEV)) that were used in order to represent a better probability of breakdown failure. In most cases, the experimental results followed Weibull and GEV distributions than other distributions. Thus, Weibull and GEV distributions were used to indicate the probability of breakdown failure of CNT nanofluids. The results indicated that CNT is considered as a potential material that would be possible to enhance the performance of mineral oil but with appropriate concentrations of CNTs. However, contradictory results occurred for CNT based palm oil, where the trend of breakdown voltage is lower than mineral oil value.