Analysis and Improvement of Potential Distribution of 1000-kV Ultra-High-Voltage Metal–Oxide Arrester

This paper presents the study on the potential distribution of the ac 1000-kV ultra-high voltage metal-oxide arrester (MOA). Based on the idea of field-circuit combination, the 3-D finite-element method (FEM) and circuit-analytic method are applied to analyze and improve the potential distribution of the 1000-kV MOA. The 3-D FEM is used to obtain the 1000-kV MOA´s potential distribution and stray capacitances to build the equivalent circuit of the MOA. With the equivalent circuit, the method to improve the potential distribution of the MOA by adding parallel capacitors is analyzed. A scheme to obtain the recommended values of parallel capacitors is achieved to improve the potential distribution coefficient within plusmn 5%. In addition, the influences of the grading ring and mounting height of the MOA on the potential distribution are also discussed. The potential distribution of the developed 1000-kV surge arrester was tested by the photoelectricity measurement method, which is close to the analysis results.