Evaluation of the sensitivity of measuring circuits for corona discharges detection

Partial discharges (PD) play a major role in the degradation of insulation in high voltage equipment. PD occurs when localized electrical breakdowns occur in the presence of a high electric field near an insulator. A critical aspect of PD measurement is the calibration of the measurement system. Calibration results in a scale factor (k), that is used to convert the measured signal to the apparent charge. This paper presents a comparative analysis of five different measurement circuits used for PD detection. The experiments were performed using a sphere-to-plane configuration. In addition to the conversion factor, this study also examines the signal-to-noise ratio (SNR) for each measurement system. Key words. Corona discharges, partial discharges, apparent charge, calibration, sensitivity.