Development of GIS fault section detection system

As of the end of 2010, 639 of 731 substations were equipped with GIS systems in KEPCO. A GIS has a small footprint, is easy to install and reduces maintenance cost compared to AIS. However, one of the drawbacks in using GIS with an enclosed metal case is that it is hard to accurately ascertain where a malfunction has occurred inside the GIS. It can cause delays in the fault recovery time and diffusing defective sections. This paper introduces how a setting value of a gas pressure sensor has been decided in a proper operation when the pressure rises rapidly through failure of GIS. Also, GIS fault section detection system with SCADA is shown. The reliability was verified by energizing the actual fault current into GIS. This detection system has been applied in two KEPCO substations. We expect the fault situation to be recovered rapidly by shutting off only the fault section. Above all, we expect that this system will lighten the burden of substation operators and reduce the mal-operations.