Grading Structure Design of Surge Arrester for 1000-kV Ultra-high Voltage Air-insulated Substation

Since it has a great height, large volume and complicated configuration, the 1000-kV ultra-high voltage surge arrester has a very nonuniform potential distribution, which leads to the depressed service life and low safe reliability. This paper proposed the three-dimensional FEM and circuit analytic method to analyze and improve the potential distribution of the 1000-kV surge arrester. An optimal grading ring structure and parallel capacitors arrangement were proposed, the potential distribution coefficient would be controlled within ±5%. The tested results show the analysis results are very accurate.