Electric Field And Its Inverse Problem In GIS Based On Numerical Computation Method

Along with the structural miniaturization and three-phase-in-one-tank of GIS, electric field distribution becomes more complex in GIS. It is an urgent demand to instruct the insulation design of electrical equipment by using reliable and effective numerical computational method and technology to calculate its three-dimensional electrical field. The electrical field intensity will be more evenly distributed in the whole domain and among phases in GIS through the accurate calculation of electrical field and effective optimization for GIS insulation structure, which is very important to design reasonable insulation structure for GIS.This thesis focuses working on the numerical computation of electric field and its inverse problem in GIS using the finite element method. We propose a MPCG algorithm to solve large algebraic equations and design a storage method for speeding up addressing coefficient matrix. A software is developed for assistant electrical field calculation which has practical engineering application value. Finally, RBFEM is applied to solve electric field inverse problem in GIS.Three-dimensional electric field of three-phase-in-one-tank GIS is calculated by FEM. The electric field distribution, the main factors affecting internal insulation and surface insulation of GIS and the effect of related structure parameters on electric field distribution are obtained by analysis of computation results. Based on these results, structure optimization for disk-type insulator is implemented by solving the related inverse problem.Since the order of coefficient matrix is up to hundreds of thousand after meshed, MPCG algorithm is adopted to solve the large equations. In order to reduce the computation cost and memory storage requirement, a novel mode is designed for coefficient matrix storage. With the algorithm and storage mode, calculation cost is cut down, while the convergence speed is kept close to the ICCG algorithm.An assistant software is developed to calculate electric field distribution and potential distribution for GIS using VC and ANSYS parametric design language. With this assistant calculation software, engineers or technicians with little FEM knowledge can also compute the three-dimensional electric field distribution and potential distribution for GIS conveniently. The software has compact user graphic interface and can select different working mode.When solving the inverse problem by combining FEM with random optimization method, there needs to mesh and calculate equations repeatedly, RBFEM is thus adopted to realize fast design optimization of electric field in GIS inverse problem. RBFEM calculate new potential vector by interpolation method based on generating reduced basis matrix with only one mesh. RBFEM provides fast calculation by decreasing matrix dimension and improve optimization efficiency greatly.