Diagnostic Technique with UHF PD Monitoring of HV GIS in Smart Grid

High voltage gas insulated switchgear (GIS) and lines (GIL) are considered as essential elements in Transmission Smart Grids. GIS and GILs are characterized by a high degree of reliability and long lifetime. Any failure in these types of equipment directly reduces grid reliability and increases maintenance costs. The failure analysis divulges that insulation deterioration is a principal factor in most of the breakdowns of GIS. Since gas-insulated apparatus are sealed structures, it is difficult to find internal incipient faults from outside. As such, intelligent condition-based asset management tools to detect the incipient faults to avoid functional failure is mandatory. Online partial discharge (PD) detection has been proven as the most effective tool for insulation degradation diagnosis. Both ultra-high frequency (UHF) technique and acoustic means have been popularly used in PD detection to enable the reliable, cost-effective life extension of existing plants. This paper presents state of the art in GIS/GIL online UHF PD diagnostics experienced by DEWA. It also explores the advantages of online PD monitoring as persuasive condition-based techniques for timely detection of potential faults. The paper also demonstrates real-life scenarios related to PD monitoring which increases the reliabilty of the grid.