The Influence of Ni2O3 Doping Concentration on the Alternating Current Aging Characteristics of ZnO Varistor

Abstract

When the surge arrester is subjected to the working voltage for an extended period, it undergoes alternating current (AC) aging, which degrades the arrester's parameters and affects the safety of the power grid. Ni₂O₃ is an important additive in the ZnO varistor formulation, and its doping ratio significantly influences the performance of the ZnO varistor. In this paper, varistor samples were fabricated by varying the doping ratio of Ni₂O₃ in the ZnO varistor, and accelerated AC aging experiments were conducted. The key electrical parameters and barrier parameters of the samples before and after aging were measured. The data show that as the doping ratio of Ni₂O₃ in the formulation increases, the volt-ampere characteristic curve of the arrester resistor shifts toward higher electric field strength before aging and toward higher current after aging. The E_1mA after aging increased from 303.58 V/mm to 442.53 V/mm. The barrier height of the samples before and after aging first increased, then decreased, and then increased again. The maximum difference was observed when the doping ratio reached 1.50 mol%. After the AC aging test, the Ni content in all samples decreased, with the smallest change rate observed in ZYN10 and the largest in ZYN15, at approximately −12%.