Research On Fast Calculation Method And Experiment Of Power Frequency Electric Field In Substation

At present the scale of power grid has been improved gradually to the Super UHV,the demand of power increase significant and uneven,110kV and low level substationsdirectly built in the center of town, so effective evaluation the frequency electric field insubstation is very important. Because the high pressure equipments in the substation arediversity and complexity, the conventional numerical calculation methods can not solvethe problem effectively. In this paper, the new fast multipole algorithm has beenintroduced based on the boundary element method, the main research works are asfollows:①The types of charge distribution and bounding surfaces of equipments insubstation have been analyzed. The simplified physical model which is suitable forsolving will get by some reasonable assumptions, The boundary integral equation withmixed boundary conditions has been established by the use of Green function; thesubdivision using triangle or quadrilateral for the different equipments according to thefinite element division technology, the linear equations obtained using the linearinterpolation; for the limitation of large computing time and storage, the iterationmethod has been studied for solving the linear equations, the preconditioned methodintroduced to speed up the convergence. Through the analysis of spherical capacitormodel, the results show that the calculation time of Generalized Minimal ResidualAlgorithm (GMRES) is obviously less than direct solution, the preconditionedtechnology make the steps of iteration reduce.②Because the computing time and storage of the preconditioned GMRES areproportional to the power of freedom, to solve large scale problems, the fast multipolealgorithm has been studied, and using the adaptive octree structure to store thecoefficient matrix implicit, the calculation time and storage are analyzed; for the largeamount of calculation about the multipole transfer process, using the index expand formand coordinates rotating to reduce the computational complexity, the new fast multipolealgorithm and the realization process have been studied. Through the analysis ofspherical capacitor and work corridor about switch field in substation, the results showthat the fast multipole algorithm has reliable calculation precision, and the precision canbe improved by controlling the multipole expand order p; the new fast multipolealgorithm make the calculation time further reduce with a few storage added. ③the expression forms of multipole shift operator has been analyzed, according tothe regular interval distribution of the polymerization center, using the fast Fouriertransform to speed up the solving of this process, the FFT with tree structure andwithout tree structure have been analyzed, and the computational complexity of theoptimization algorithm has been studied. Through the validation of models, the resultsshow that the precision of optimization algorithm is higher than the original fastmultipole algorithm; computation time and storage are decreased obviously.④Through the measurement of electric field about the switch field at high voltageside in110kV substation, we got the electric field distribution on attention plane;modeling with the actual size of high voltage switch equipments, Firstly use the ANSYSto analyze; then use the software Patran2010to divide the bounding surfaces, use ouralgorithm to solve, and the results shown by the Tecplot. Through the comparison withthe test data, further proof our algorithm is suitable for solving the large scale problemof power frequency electric field distribution in substation.