Assessment of Corona with Partial Discharge and Radio Interference Measurement Circuits

The paper presents how the physical phenomenon, corona discharge, can be assessed using circuits for measuring partial discharges (PD) and radio disturbances. In test circuits for PD measurement, corona discharges may also be present as a disturbing element at certain test voltages, even if all measures are taken to avoid them. The main features and differences between the PD measurement circuit and radio interference voltage measurement circuit are presented, which include the measurement systems and their calibration methods. So for the PD measurement are presented calibration of the PD circuit with the same impulse charge but using different type of filters at PD instrument (wideband and narrowband). For the radio interference voltage measurement is presented calibration of the test circuit with the same voltage but with using different frequencies at the electromagnetic interference receiver. In a test circuit simulating the occurrence of corona discharges, corona discharges were evaluated at different test voltages using the same measurement frequencies for the two systems. Differences were observed between the results obtained with the same measurement frequencies for the two systems, differences that were maintained regardless of the measurement system used. The UV spectrum and the electric field of these discharges are correlated with the applied voltage. To assess the corona discharges, the electric field generated by these discharges at the highest test voltages was also measured.