Characteristics of transient electric field induced by VFTO based on field measurement

The transient overvoltage will be produced inside GIS (Gas Insulated Switchgear) when disconnector switches operate because the speed of disconnector is very slow and it does not have the arc extinction ability. The VFTO will lead to the electromagnetic interference for the smart devices in substation which will damage these devices. A transient electric field detection system is established in this paper. Based on this system, the field test is carried out. The transient electric field signals excited by VFTO are measured when the disconnectors and switchgears operate. Analyzed by time-frequency method, the detection results show the frequency of transient electric field caused by disconnector operation is higher than that of switchgear operation. The electric field strength is stronger when the disconnector switches out than switches on. The frequency distribution of electric field caused by disconnector switches off is below 80 MHz and concentrates on 16, 23, 31, 46, 56, and 80 MHz. For the disconnector switch on, the frequency is below 50 MHz and concentrates on 6, 10,16,23,31, and 46 MHz. The detection results in this paper provide the basic data for the analysis of interference caused by VFTO.