Influence of Series Resistance on Dry-Band Discharge Characteristics on Wet Polluted Insulators

This paper describes the current dependence of dry-band discharge. Model electrodes that simulated the dry-band was introduced. The dependence was examined on the voltage and current waveforms, emission spectra and their intensities, rotational temperature, etc. As a result, two different discharge types, continuous and intermittent discharges, were observed in a half cycle of applied ac voltage. They were characterized by continuous current and light emission, and by pulsative current and intermittent light emission, respectively. The duration of the continuous discharge decreased with the value of series resistance, while that of the intermittent discharge increased. The rotational temperatures of the continuous discharge and the intermittent discharge were about 6000 K and 1500 K, respectively. The spectral emission intensity related to the electrolyte during the continuous discharge was higher compared with the intermittent discharge, and decreased with the value of series resistance. The spectral emission intensity related to nitrogen molecule during the intermittent discharge was almost constant irrespective of the value of series resistance. The characteristics of the continuous and intermittent discharges corresponded to those of the terminated partial arc and spark (scintillation), respectively.