Comparison of the PD characteristics of epoxy resin under exponential decay pulse and sinusoidal voltages

Abstract

The saturable reactor insulation epoxy resin is subjected to exponential decay pulse voltage under normal operating conditions. It is of great importance to study the partial discharge (PD) mechanism of epoxy resin under exponential decay pulse and sinusoidal voltages for optimal insulation design. Thus, the difference in the PD behaviours under the exponential decay pulse and sinusoidal voltages is revealed in this study for the first time, and the PD characteristics of the two types of voltages are compared and analysed at 25 and 110°C. Compared to the results for sinusoidal voltage, a higher amplitude, lower repetitive PD inception voltage peak (RPDIV) and fewer PDs are obtained under an exponential decay pulse voltage. Additionally, for the same type of voltage, the RPDIV is lower, the PD magnitude is higher and the number of PDs is smaller at 110°C than those at 25°C. The experimental results can provide a new reference for the insulation redesign of a saturable reactor under an exponential decay pulse voltage.