Evaluation of lifetime of air-insulated switchgear versus service conditions in MV substations

Air-insulated switchgears are particularly sensitive to environmental conditions of the substation where they are installed. In order to establish the relationship between the state of switchgears and service conditions in substations, it is important to assess the actual service conditions. The three most important parameters influencing the lifetime of switchgears are relative humidity, condensation generated by the temperature instability, as well as the pollution level. The aim of this study is to give some indication based on a return of 30 years of field in typical utility environment, in order to assess the expected and remaining lifetime of switchgear installed in DSO's substations.