PD Monitoring System for HV Substations

摘要

Substations are integrated in residential, commercial and industrial areas sharing the same buildings and installations. Unexpected failures due to insulation defects appear periodically in substations and can cause large damages, loss of service supply and even blackout. Unfortunately sometimes these failures involve catastrophic fires and emission of toxic gases to the atmosphere.To assure service continuity, electrical insulation diagnosis measurements are needed in substations. Different kinds of measurements (partial discharge - PD -, C, tan, and temperature) permit to determine global or local insulation condition of electrical machines and equipment. This paper is focused on PD measurements in service applied to the three main different types of equipment installed in a substation: power transformers, GIS and bridge insulated cable systems to interconnect the power transformers to the GIS.An integrated solution consisting of a PD measuring system is presented in this paper to get comprehensive PD monitoring of a complete substation. The integrated PD monitoring system for substations has to be able to automatically remove background noise, locate PD sources, discriminate different PD sources located at the same place and identify type of each located PD source. Travelling PD attenuation, phase-resolved PD patterns of different PD sources in different devices and PD sensitivity of different PD sensors used are analyzed in the paper. Special algorithms on the basis of redundant PD data are applied to investigate type and location of different PD sources.The paper also includes real Unión Fenosa Distribución’s experiences of on-line PD measurements using the new PD approach for PD monitoring where internal defects in GIS, cable terminations and power transformers were detected, analyzed and repaired.