ANALYSIS OF BREAKDOWN STRENGTH AND PHYSICAL CHARACTERISTICS OF VEGETABLE OILS FOR HIGH VOLTAGE INSULATION APPLICATIONS

The success of any electrical system lies in its insulating system performance. Petroleum based mineral oils are the generally used fluids for electrical insulation and heat transfer. But they are non-biodegradable. Vegetable oils obtained from seeds, flowers and vegetables are biodegradable, non-toxic, environmental friendly and benign to aquatic or terrestrial. The objective of this paper is to analyse the breakdown strength and physical characteristics of extra virgin olive oil and castor oil under unaged and thermally aged conditions. In order to compare the results obtained for vegetable oils with mineral oil, the same aging process and tests have been carried out on mineral oil

UNDERSTANDING THE LIGHTNING DISCHARGE WITHSTAND AND BREAKDOWN CHARACTERISTICS OF NANO SiO2 MODIFIED MINERAL OIL FOR TRANSFORMER APPLICATIONS

The successful operation of electrical power system network depends on the performance of insulation provided in the high voltage power transformers. Recent output of many research works confirm that the nano modified insulation system provides enhanced dielectric and thermal characteristics when compared with conventional system. Now a days nano modified mineral oils are considered as an alternative to conventional mineral oils as a dielectric insulation fluid in power transformers, leading to the improved dielectric strength of apparatus with further reduction in the size and manufacturing cost. Since distribution transformers are mainly used in outdoor applications, understanding its lightning discharge withstand and breakdown characteristics of nano modified insulating fluid is a vital issue. In this paper laboratory experimental works are performed to understand the lightning discharge performance of mineral oil along with SiO2 nanofiller at different %wt concentration such as 0.01%, 0.05% and 0.1%. Standard lightning impulse voltage of 1.2/50 µs time period with both positive and negative polarity is used in the experiments. Results illustrate that the nano modified mineral oil significantly improves the lightning impulse withstand and breakdown strength of insulation system.Â