Karanji oil as a potential dielectrics liquid for transformer

Abstract

This paper presents a nonedible karanji base vegetable oil (VO) as an alternative transformer oil. The nature of biodegradability, environment friendly and easy availability makes this oil a suitable candidate for liquid insulation. The crude karanji oil (CKO) is not at all suitable for the transformer use because of the higher acid number and viscosity, it will affect negatively on the heat transfer and flowability of liquid inside the transformer. Two step transesterification process has been followed for the extraction of karanji oil methyl ester (KOME) from CKO. Characterizations like Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance ( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H-NMR) and gas chromatography-mass spectroscopy (GCMS) of the KOME are carried out to ascertain the formation of methyl ester oil. Thermophysical properties such as thermal conductivity, viscosity, density, interfacial tension, colour, flash point, pour point, chemical properties such as acid and iodine number, moisture and electrical properties such as dielectric strength, dielectric dissipation factor, and dielectric constant are measured as per standard and compared with mineral oil (MO). AC breakdown voltage (ACBDV) of the KOME is studied and the Weibull statistical analysis is carried out at 95% confidence interval to evaluate breakdown probability. Oxidative ageing of MO and KOME are performed and the effect of thermal conductivity and ACBDV with ageing are studied. It is observed from the results that the performance of the KOME is superior then MO for transformer application.