A Study on Multi-Factor Ageing of Insulation Systems

Electrical insulation is an important component of high voltage equipments and it affects strongly the reliability of whole systems. But generally the enduring properties of insulating materials for thermal and mechanical stresses are inferior to those of main constructing materials of machines such as copper and iron. Then the ageing characteristics of insulation systems has been investigated for long time as an important subject by many reseachers, and the most of these investigations have been done as single factor ageing so far, such as thermal, voltage and mechanical ageing. But in recent trend of larger unit of power equipments, the demand of higher stress design of insulation has become larger, and consequently it has become more important to clarify the multi-stress ageing characteristics of insulation systems, and now they are being studied in the whole world. This paper describes an analytical method to derive the multi-factor ageing characteristics of insulation systems b