Study On Typical Defect Field In GIS Interior

GIS is the core component of the electric power system.In the case of high voltage,even very small defects may lead to insulation breakdown.Therefore,for the research of GIS internal defects changing electric field is of great important.Based on GIS single-phase model and compact GIS three-phase model,and considering existence of burrs,simulation models are established.And research of field in the GIS is carried out.In this thesis,the main work is as follows:Firstly based on the electrostatic field finite element method(FEM)and SF6 gas discharge ionization theory,GIS single-phase models is studied.According to the position of the burr,there exist two types: high voltage conductor burr and ground electrode burr.The relation between electric field intensity and burr parameters is studied.Based on the theory of SF6 gas ionization discharge,relationship between electric field intensity and burr parameters is simulated.Safety area is defined.Secondly,compact GIS three-phase model is established.The influence of the burr on GIS electric field intensity is studied.By changing the parameters of burrs of the radius and height,the relation of the burr electric field intensity and the burr parameters is researched.Finally,based on GIS coaxial model,the effect of defects over basin insulator on internal GIS electric field is simulated.Electric field intensity is analyzed when burr is on the basin insulator concave and convex surface.The relation of electric field with the distance between burr and high voltage conductor is also studied.From simulations conclusions can be obtained.As for the burr of GIS single-phase model,as burr radius being constant,the electric field intensity increases with burr height;as burr height being at constant electric field intensity decreases with radius.As for compact GIS three-phase model,the electric field intensity spurts on a phase where the high voltage conductor burr exists.There is no effect on the other two phases,and the ground electrode burr only has an effect on the shell of electric field intensity in the study of this thesis.In the study of compact three-phase model,burr electric field intensity is mainly related with the burr radius.With the increase of radius of burr,the electric field intensity value decreases.For GIS basin insulator,burr's influence on the convex surface electric field intensity is bigger than that on concave;Burr nearer the high voltage conductor makes the basin insulator electric field intensity bigger,the smaller the vice.