Performance Analysis of Dielectric Properties of Blended Neem and Olive Oils using TOPSIS and Fuzzy TOPSIS Methods for Power Transformer

A power transformer is the power distribution system's essential component that must be contractually monitored. The electricity supply has to be uninterrupted to keep a harmonious balance between consumer demand and supply, which depends on the reliability of the transformer. Also, liquid insulation that offers efficient cooling and insulation is very much crucial to the lifespan of the transformer. Conventionally, mineral oil is being used as a coolant and insulation medium for power transformers, which is a derivative of petroleum. The objective of this proposed investigation is to reduce reliance on fossil fuels that are increasingly scarce and to upsurge the use of oils derived from renewable sources. Thereby, to overcome the limitations of mineral oil, such as its poor biodegradability and weak flash and fire point, recent research has concentrated on natural ester liquid, environmentally acceptable insulating oil with commendable dielectric properties. In this paper, investigations were conducted to examine the functionality of olive oil, neem oil, and its blended samples at different proportions to replace mineral oil employed as liquid insulation in power transformers. The characteristics investigated are breakdown voltage, viscosity, moisture content, and oxidation stability of blended samples per IEC and ASTM standards. The multi-objective optimization tools such as TOPSIS and fuzzy TOPSIS were employed to optimize and choose the suitable natural ester for power transformers. Among the samples, NM50+OL50 presents a higher breakdown voltage of 59.96 kV with an induction time of 1.26 hrs and a viscosity of 42.92 cSt at room temperature. It was found that TOPSIS and Fuzzy TOPSIS methods have computational robustness in selecting NM50+OL50 as a suitable alternative to power transformers among the blended samples.