Optical measurements for interfacial conduction and breakdown (1980)

Techniques were developed to measure the fields in transformer oil using Kerr effect and to measure the surface charge at a gas-solid interface using the Pockels effects. Measurements are supplemented by calculations of the distortion produced by selected interfacial charge distributions. The relatively pure transformer oil used showed little space charge distortion of the electric field. There also was no statistically significant preference for breakdown in the vicinity of the interface. At vacuum-solid interfaces, however, interfacial breakdown was observed and surface charging was measured. As gas is introduced into the system, the surface charge is removed so that no effect of surface charging was detected at atmospheric pressure. At pressures above atmospheric, there is evidence that surface charging may again become important.