The Multifactor Aging Characteristics and Aging State Assessment of Epoxy Composites for GIS

Epoxy and its composites are widely used as raw materials for the solid insulations in gas-insulated switchgear (GIS) worldwide due to their excellent dielectric properties, thermal stability, corrosion resistance, and ease of processing. These insulation materials show aging phenomena under multiple stresses of electrical, thermal, and vibration during GIS operation, which reduces the electrical and mechanical strength of solid insulation, and further leads to operational failures in GIS. Therefore, it is crucial to study the aging characteristics of epoxy composite under the influence of multiaging-factor and assess their aging state. To explore the inherent characteristics of epoxy composites, this article designs a recessed-type specimen and the corresponding testing platform for multifactor aging experiments and aging state parameter tests. The epoxy composites are aged by different combinations of electrical, thermal, and vibration stresses. The dielectric parameters and partial discharge (PD) voltages are measured in selected time intervals. And the aging characteristics and aging state assessment of the epoxy composites under multiple aging factors are discussed, which has certain guiding significance for the maintenance and retirement of solid insulations in GIS.