In Reference to the Simulation of Partial Discharges in Solid Dielectrics

Abstract

Partial discharge simulation is usually carried out using equivalent circuits. The accuracy of the simulation mostly depends on the number of elements representing the physical processes in insulation. The paper presents the simulation results of partial discharges in a sample of solid insulation made of cross-linked polyethylene. A resistance-capacitance equivalent circuit was taken as a model, in which the capacitance of the air cavity at the moment of the partial discharge ignition is shunted by the active resistance of the spark. The moment of a partial discharge ignition is determined by the ignition voltage, and the moment of extinction is determined by the magnitude of the current. The circuit takes into account the active resistances of insulation and air cavity. A number of results have been obtained with the use of MATLAB® Simulink. The results allow evaluating the averaged characteristics of partial discharges in the insulation sample, the influence of the defect size on the apparent and true charges magnitudes. The work evaluates the diagnostic magnitudes of the apparent and true charges, presents the results of their relationship with the cavity parameters.