Finite element calculation and experiment of potential distribution for a 500 kV porcelain zinc oxide arrester

Chargeability is a crucial parameter for the design of ZnO arrester. For a 500 kV porcelain ZnO arrester, its potential distribution is calculated with finite element method, where reasonable boundary is set to simplify the solution of the open boundary field problem, and the strategy of coupled degrees of freedom is adopted to deal with the floating conductors. Then the potential distribution of the arrester is tested with optical fiber-current measurement method under the maximum continuous operating voltage. Compared with the calculation results, the validation of the proposed method is verified. Finally, the influences of the size of calculation boundary, the parameters of grading ring and the mounting height on potential distribution are analyzed, and the results demonstrate that the potential distribution coefficient of the upper and lower sections of MOA can be improved through increasing mounting height, and the lower grading ring has more significant influence on the potential distribution.