Gas insulated switchgear(GIS)taking SF6/N2 gas mixture as insulating medium can effectively reduce environmental pollution,and it has gradually been applied in GIS at 220 kV and below.Considering that poor contact of bus joint is a common defect,it is necessary to study the temperature distribution of bus joint of GIS with SF6/N2 gas mixture during poor contact.Firstly,a 3D simulation model of multi-physics coupling for 220 kV three-phase enclosed bus with SF6/N2 gas mixture is established.By setting a resistance film at the bus joint to simulate the poor contact state,the temperature distribution law of bus joint of different phases with poor contact is calculated and analyzed.And then,the method for diagnosing severe internal heating defects using the surface temperature differences of shell is studied.The results show that when the contact of any phase bus joint is poor,the highest temperature point will appear on the corresponding position of shell surface,and when the top two bus joints are heating and the temperature differences on shell surface reach 2.5 K,or when the bottom bus joints are heating and the temperature differences on shell surface reach 2.0 K,it could be diagnosed as a serious defect.
gas mixturepoor contacttemperature distributionmulti-physics couplingdefect diagnosis
万方数据
