| The over-voltage in GIS equipment usually has high amplitude and frequency due to the compact structure.The insulation characteristics of SF6 gas not only depends on the inhomogeneity of electric field in insulation structure,but also are closely related to the steepness of the voltage source.Therefore,the research of the dynamic electric field distribution in GIS is very necessary to guide insulation design.Because of the superiority of time domain finite difference method（FDTD）,the FDTD method is used to simulate the dynamic electric field distribution in GIS.First of all,the key problems in each procedure of the FDTD simulation are discussed to improve the performance in the GIS electric field calculation.We find that the focal points include two aspects,i.e.,gridding algorithm and absorbing boundary condition.Then,we classify the GIS into coaxial bus duct and GIS equipment according to its structure characteristic,and study the key problems.In order to model the GIS coaxial bus duct,a general technology which is used to gridding the conductor and dielectric is put forward,and the key technologies of conformal grid information generation are introduced.Then we analysis the stability of the gridding technology and compare the influence of different factors.In order to calculate the electric field of complex equipment accurately and improve the computational efficiency,the non-uniform gridding method is introduced.New problems in modeling complex equipment are studied,including the generation of conformal mesh information and how to deal with singular points.Then the validity of the algorithm is verified,and the selection rules of the absorption boundary condition are given.Taking the 500kV GIS bus duct and disconnector made by Shanghai Siyuan electric company as study example,the transient electric field under very fast transient overvoltage（VFTO）and lightning wave is calculated using FDTD method,which validates the significance of calculating transient electric field. |
PDF Full Text Request