Electric Potential near the Tip of a Local Discharge on an Electrolytic Solution in the Low Pressure Air

Abstract

An electrolytic solution surface was used to simulate the surface of wet polluted insulators. When a local discharge propagates on the electrolytic solution under an impulse voltage, the discharge current flows in the electrolytic solution through the contacting surface between the local discharge and the electrolytic solution. Accordingly, a potential distribution occurs along the electrolytic solution. The authors examined the shape of the contacting surface between the local discharge and the solution. By using the shape of the contacting surface, an electric potential near the tip of the local discharge on the electrolytic solution was calculated. A source of the discharge current at the contacting surface is replaced by charge and the potential on the electrolytic solution is calculated with the image method. In this paper, the potential was measured along the solution in the low pressure air with a probe. The calculated values and the measured values of the potential agreed well regardless of the peak value of the applied voltage, the resistivity of the solution, and the waveform of the applied voltage.