Experimental Investigation on the Influence of AC Voltage on Positive Corona Current Pulses from DC Conductor Parallel with AC Conductor

Abstract

In this paper a DC conductor is set parallel with an AC conductor in the laboratory to study the influence of AC voltage on the characteristics of positive corona current pulse. The corona onset voltage of DC conductor and the detail characteristics of corona current pulses such as the rise time, the amplitude, the pulse width and the repetition frequency are systematically analyzed. It is found that the corona onset voltage of DC conductor decreases linearly with the increase of AC voltage. Due to the influence of AC voltage, the distribution of corona current pulses gradually forms into periodic clusters and the repetition frequency of the clusters is equal to the frequency of AC voltage. Meanwhile, the obtained results show that the average current amplitude decreases with the increase of separation distance, rise time increases with the increase of separation distance and the current width changes uniformly with separation distance. Meanwhile, AC voltage and the separation distance have an influence on the repetition of current pulses. Through the calculation of the average ionization boundary and ionization coefficient integration, the mechanism of the influence of AC voltage and separation distance on the corona of DC conductor is qualitatively analyzed.