Abstract
In this papar, we observed a local discharge propagation on an electrolytic solution surface, which simulates the surface of wet polluted insulators, under an impulse voltage. Resistivity of the electrolytic solution was changed in the range of 85Ω•cm-3kΩ•cm. To examine a local discharge propagation, we used a Schlieren technique. A ray of light from a spark light source was transmitted to a electrode system.
As a result, we found shock waves and density changes. Shock waves were generated from tip parts of a local discharge. Velocity of the shock wave generated from a discharge during the local discharge propagation was about Mach 1.1. From a measurment of Mach angle, a local discahrge propagation velocity was obtained. That velocity at starting point of the propagation was in the range of Mach 2.5-4.7 for 85Ω•cm of the resistivity of the electrolytic solution, Mach 3.5-5.4 for 600Ω•cm, Mach 4.3-5.7 for 3kΩ•cm respectively.
