The Leakage Current and Flashover Voltage of Polyethylene Insulator with Different Contour Surfaces

This paper reports the results of research on the effect of the surface contour shape of polyethylene insulator on the leakage current and flashover voltage. Three types of insulator surface contour, namely type-A, type-B, and type-C, have been considered. The three contours possess the same creepage distance, but with different fin diameters, so that each type has a different shape factor. The rod-electrode has been used during experiment. The distribution of electric field on each contour type has been observed using finite-element method-based software. Results of experiment showed that all the three considered insulators produced highly inhomogeneous electric field distribution. The highest homogeneity level has been found on the type-A insulator, whereas the least homogeneous field condition has been produced on the type-C insulator. The most homogeneous field on the type-A insulator is related to the lowest shape factor and brings about the lowest leakage current, corona inception voltage, and flashover voltage. The flashover and corona inception voltages could also be improved using the appropriate configuration of upper and lower fins position, which would also lower the insulator leakage current level.