Application of UHF-based partial discharge detection and analysis of tar-polluted insulator of a wet ESP unit

Abstract

This paper investigates partial discharges occurring on the tar-polluted surface of a porcelain insulator through UHF-based non-conventional partial discharge measurements. First a sample is extracted from an actual tar-polluted porcelain insulator, and the UHF signals arising due to partial discharges on the tar-polluted surface are recorded and analyzed. The patterns manifested by the surface discharges are studied and the respective signals are analyzed in time and frequency domain. Once this is accomplished, pertinent findings are validated on an actual porcelain insulator installed in a wet electrostatic precipitator unit. It is expected that the results from the test sample and on-site validation may help in improving existing maintenance strategies, thereby minimizing procedures hazardous to the environment and human life. At the least, the typical response of tar and its influence on the condition of the porcelain insulator must be determined in the macroscopic scale, which still requires deeper investigation.