Practical application of partial discharge measurements at epoxy impregnated coils for analyzing signal noise in the radio frequency range

In order to analyze the partial discharge signal noise in the radio frequency range, the signal characteristics of partial discharge pulses generated in a large-scale epoxy-resin impregnated coil are analyzed in this paper and compared with the partial discharge behavior at lower frequencies. Partial discharge inception voltages generally are higher when measured at radio frequency level compared to standard measurements. Two different pulse types, single and double pulses or different void types account for the variations in the partial discharge behavior.