Abstract
We investigated creepage discharge propagation characteristics on PET films by applying an impulse voltage in SF6 gas under the influence of surface charging. Experimental results revealed that the impulse creepage discharges on the charged surface with -4 to -12kV extended to distance at maximum 20 times longer than the case of uncharged surface. It was also found that the flashover voltage VFO had a power law dependence on the capacitance Cs of the sample, i.e. for Cs=11.3 pF/cm2, VFO decreased 2/3 as a result of charge formation with -12kV surface potential in comparison with uncharged case. Further, to discuss the mechanisms of creepage discharges with and without surface charges, measurements of light emission and current flowing through the back electrode were also performed when creepage discharge occurred. As a result, the existence of the surface charging proved to remove the pulsive component of the waveforms of the current and light emission on part of the wavetail. The results suggested that the surface charging causes the creepage discharge to extend to longer distance than for uncharged case.
