Accurate measurement of original current pulses because of positive corona in the coaxial cylindrical arrangement

Current pulse because of positive corona discharge is a main source of radio interference (RI). An accurate measurement of the original corona pulse is necessary to study corona-generated RI. However, the corona pulse is likely to be distorted by either LC oscillation or reflection. In this study, an experiment system with single corona source is built which can provide a nearly free-reflection path for the current pulses, and measurements are carried out in the system. The magnitude of the measured waveform is close to one half of the original pulse, which proves the accuracy of the measurement method. In order to obtain the original current pulse, a comprehensive model for the current pulses' path, taking the stray capacitance and stray inductance into consideration, is established. Based on the model, an inversion method to derive the original pulse is proposed. In combination with the obtained original pulse, the model gives the calculated results for other experimental conditions. The calculated results agree well with the measured results, which provide solid validation for the accuracy of the measurement. Another advantage of the proposed measurement method is that the long cables enable the accurate measurements to be achieved under any terminal conditions.