Research of electrophysical properties of oil-paper insulation

The transformer plays an important role in providing a reliable and efficient electricity supply and is one of the most critical equipment in electric power transmission and distribution systems. The mineral oil paper insulation system is successfully used in transformers for many years. Today great emphasis is accentuated on the use of materials environmentally friendly. Natural ester is considered to be a substitute of mineral oil. This paper is focused on electrophysical properties of rapeseed oil - paper and mineral oil - paper insulation system. Dissipation factor and breakdown voltage of paper impregnated by mineral oil and natural ester were measured. Properties of mineral oil paper insulation and rapeseed oil paper insulation are compared.