Nynas Naphthenies - AB, SE-۱۴۹ ۸۲ Nynashamn Sweden

Insulating oil in service is subjected to heat, oxygen and electrical discharge, which may lead to chemical breakdown. This severely limits the oil to carry out its primary functions of insulating and heat transfer as breakdown products reduce electrical properties and cooling efficiency. Oxidation products, such as acids and sludge, are also detrimental to paper insulation. Therefore, monitoring and maintaining oil quality is essential in ensuring the reliable operation of oil-filled electrical equipment. Much greater difficulties exist ill deciding frequency of testing and permissible oil degradation levels. This paper describes guidelines and a code of practice for in-service insulating oil based on the results of research on insulation ageing. The paper also seeks to show the best compromise between technical requirements and economic considerations.

Insulating oil, oil maintenance, oil ageing, paper ageing, oil management