Dielectric spectroscopy characteristics of new and aged high voltage insulating polymeric materials
Increased use of solid polymeric materials in the insulating structures of high voltage equipment for electric power systems over the past years has occurred despite a lack of understanding about how these materials age while in service. Therefore, studies of ageing are crucial for power system reliability and are important for both key participants of the electric power industry: utilities and consumers. The development of an accelerated ageing procedure that mimics the presence of the thermal gradient across the insulating structure is reported. A test module that applies a constant thermal gradient across a sample of insulation material has been designed, built, and tested. An additional study was conducted into evaluation protocols for ageing of polymeric materials used for outdoor applications based on the dielectric spectroscopy measurements: certain refinements to this method are proposed. A comprehensive sensitivity analysis has been developed to estimate uncertainties of the measured dielectric parameters.