The influence of accelerated ageing on the oil impregnated paper

One of the most important parts of electric power equipment is the insulation system. Insulation system must be in a good condition for reliable and safe operation of electrical devices. During the lifetime of the electrical equipment, insulation system is exposed to various factors which could have negative influence on the properties of the insulation system. High temperature is one of the factors known to cause a degradation of the insulation system. Insulation system of transformers consists of two parts - liquid and solid. Liquid portion is represented by insulation oil and the solid one is represented by insulation paper. This paper focus on the investigation of how an accelerated ageing influences the properties of oil impregnated paper. Vegetable oil with its high flash point, high degradation rate and the reproducibility represents a potential new type of insulation oil which is expected to replace currently used mineral oils. Research of the vegetable oil properties is therefore a crucial step towards its future use. Properties such as relative permittivity, dissipation factor and the breakdown voltage will be described and analyzed.