Study Of Electromagnetic Interference Characteristics Caused By Disconnector Operation In GIS

Gas insulated substation(GIS)is widely used in EHV and UHV power systems because of its safety and small floor area.However,the operation of disconnector in GIS will produce a series of transient processes,which will excite the transient space electromagnetic field near the GIS line.At the same time,the transient current enters the grounding grid through the shell grounding lead,which will increase the potential of the grounding grid.With the deepening of the current intelligent development direction of GIS Substation,more secondary equipment and cables are placed near the GIS line,which are very vulnerable to electromagnetic interference,causing damage,and then affecting the normal operation of the power system.Therefore,it is of great significance to study the electromagnetic interference characteristics caused by the action of disconnector in GIS.The main research contents of this paper are as follows:(1)In this paper,550 k V GIS is selected as the research object,and the electrical components in GIS Substation are equivalent modeled according to Bergeron numerical calculation method.According to the selected switching operation mode,the transient circuit model is established through EMTP simulation software to calculate the ultra fast transient overvoltage and overcurrent generated by disconnector operation,and calculate the potential rise of GIS shell.At the same time,the main frequency components and distribution range of the waveform are obtained by spectrum analysis.(2)The three-dimensional calculation model of GIS Substation structure is established.According to the time domain finite integral method,the transient spatial electromagnetic field at different positions near the GIS line under the operation of disconnector is calculated.The main frequency components of electromagnetic field waveform and the variation trend of electromagnetic field with distance from the GIS line are analyzed.At the same time,the electromagnetic field distribution near the centralized control cabinet in the substation and inside the cable trench is calculated,the distribution law of the electromagnetic field is obtained,and its influencing factors are analyzed.It can provide reference for the location and installation of secondary equipment.(3)The transient rise of grounding grid potential caused by GIS disconnector operation is calculated by using CDEGS simulation software.The influence of different soil parameters and buried depth of grounding grid structure on the rise of grounding grid potential are analyzed.At the same time,the potential difference of the grounding grid at both ends of the grounding cable is considered,and the effects of the injection of transient current from different positions,the number of transient current entry points and different cable layout structures on the potential difference at both ends of the cable are analyzed to obtain its variation law,so as to provide suggestions for the layout of the cable.