Frequency distribution of RF energy from PD sources and its application in combined RF and IEC60270 measurements

Using an integrated measurement system, partial discharge activity has been recorded simultaneously in terms of radiated energy and IEC60270 apparent charge. Correlation between these two quantities can yield important information regarding the shape of the underlying PD pulse. It is proposed that this new measurement strategy can be further enhanced by additionally calculating the relative spectral energies of the measured RF signals. The spectral energies of radiated RF PD pulses vary depending of the topology of the defect source and therefore may serve to enhance the quality of diagnostic information. Results indicate that the frequency distribution of RF energy measured simultaneously along with apparent charge could prove useful as an additional means of defect identification and characterisation.