Study on waveform parameters of impulse test voltage and on-site docking method for EHV/UHV GIS

GIS (gas-insulated metal-enclosed switchgear) is one of the important components in modern electrical power systems. Compared with traditional open switching devices, GIS has many advantages such as compact structure, smaller occupied area, little influence from environment as well as safe and reliable operation [1-3]. Statistical data show that equipment failure rate of GIS is only 20%-40% of traditional open switching devices. However, as GIS is designed as a fully enclosed structure, once something goes wrong, the diagnosis process is much more complex and the time necessary for fault repair becomes much longer [4-5]. For instance, a severe short circuit fault occurred in Jiangsu Power Grid, China in 2014 due to the development of cracks on a disc insulator. In the same year, abnormal discharges occurred in GIS substations because of a disconnector fault that led to large economic loss and undesired social impacts. Much work had, therefore, been done on analyzing transient events in gas insulated installations in China and internationally [6-9].