Effect of MnO2${ ext{MnO}}_{2}$ doping on AC aging characteristics of varistor in arrester

Abstract

Abstract As the core component of lightning arrester, the performance of ZnO varistor directly affects the protection level of lightning arrester. Under the action of long‐term AC voltage, the varistors are prone to AC aging, which leads to the deterioration of its performance parameters and microstructure, resulting in the failure of the varistors. In this paper, the effects of MnO2 doping on the voltammetry and double Schottky barrier characteristics of ZnO varistors under AC were studied by means of C--V, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy characteristic testing. The AC accelerated aging test was carried out for 168 h under 135∘C and 0.85 ratio of peak voltage. The results showed that the introduction of Mn4+ inhibited the migration of interstitial zinc ions to grain boundaries and decreased the AC aging rate. The aging rate was lowest when 1.5 mol% MnO2 was doped.

Keywords

• AC aging
• MnO2${ ext{MnO}}_{2}$
• Schottky‐barrier
• V–I characteristic
• ZnO varistor