CALCULATION OF POTENTIAL DISTRIBUTION FOR ZINC-OXIDE SURGE ARRESTER BY FINITE ELEMENT METHOD

Finite element method (FEM) is applied to the calculation of potential distribution for ZnO surge arrester with open boundary. The open boundary field problem is transformed to the bounded field problem through setting artificially truncating boundary with asymptotic boundary condition. The vitual homogeneous imposed boundary is presented to deal with a great number of floating conductors in the surge arrester. The potential distributions of 330 kV and 500 kV ZnO surge arrester are calculated and measured. The numerical results show that the method is correct and efficient. Some conclusions are also concluded as follow. The potential distribution of ZnO elements tends to be uniform with the increase of mounting height. The maximum ratio of born potential will be decreased greatly in presence of equalizer ring so that the potential distribution of ZnO elements could be improved. Compared with other methods based on simulation electric charge, our method is advantageous for its simplicity,generality and sufficient utilization of existing program. It can well satisfy the demands of engineering design and application.