| The Gas Insulated Switchgear (GIS) equipment have been widely used in all the levels ofsubstation. The superior performance of GIS is based on the structure that the high-voltageequipment is completely sealed by a strong metal shell. This structure keeps the innerhigh-voltage equipment free from the external environmental interference, and the SF6gaswithin the GIS keeps the electrical equipment from being oxidized, which makes theprobability of GIS breaking down reduce to the minimum. Although the strong and sealedshell provides good protection for the GIS, it also brings problems on maintaining andmonitoring. The inner equipment may occur insulation fault in the production, transportation,installation and normal operation period, which will lead to partial discharge (PD) in the GIS.The existence of shell makes the operating crew hard to discover the defects inside the GIS,while the development of PD will probably lead to a serious insulation breakdown orshort-circuit accident. The high-cost and time-consuming repairing work of GIS, becomes amajor threat of the power grid safety.In order to realize the condition-based maintenance of the220kV GIS equipment inDieling substation, the Power Supply Bureau of Yangjiang has established and applied aLBPD-2100GIS PD online monitoring and fault diagnosing system. The system based on theUltra High Frequency (UHF) technology can execute real-time supervision of PD inside GIS,an alarm will be hit once PD is detected and the analyzing and diagnosing program will beproceeded. The practical operating instance in which the system guided the repairing crew toeliminate defects inside GIS by giving an alarm and locating the PD spot, proves that theLBPD-2100system can achieve condition-based maintenance of GIS. The system also givesfalse alarms caused by external electromagnetic interference, indicating its anti-interferencemeasures should be upgraded. |
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