Use of natural vegetable oils as alternative dielectric transformer coolants

Abstract

This paper discusses the present efforts by researchers to develop and provide an alternative means of cooling and insulating transformers. These efforts are borne out of the obvious importance of transformers in electrical power supply network, and the present realisation that the existing method of cooling falls short of specifications. Most importantly, is the inability of mineral and petroleum oils to comply with environmental regulation laws. Natural vegetable oils have been found to meet the specifications since they have high flash points (300°C), high fire points (250°-300°C), lower pour points (-10°C) and have high dielectric breakdown voltage (>50KV). These are in conformity with standards like IEEE C57, IEEE 637, ASTM D6781 and IEC 60296. Their biodegradability make them safe for use in densely populated areas and close to waterways. This also makes them to be environmentally compliant and avoidance of sanctions from regulatory agencies. Since they are from renewable sources, their production and utilisation is simple and cost effective. Overall, this can ensure sustainable development. This work has also measured the properties of palm oil against the IEEE C637, and ASTM D section for possible use as a dielectric fluid. The result shows that treated palm oil has break down voltage of 75 KV/mm, flash point (>220), fire point (>220) and moisture content (0.08%). Hence this has shown the potential of palm oil as a dielectric fluid. However future work should focus on further investigation before field application