The characteristics of internal partial discharge, moisturizing, surface pollution and thermal breakdown of ZnO surge arrsters were analyzed, and how to diagnosis these problems were introduced.

• 分析了避雷器内部局部放电、内部受潮、表面污秽及热破坏等现象的特点，介绍了如何根据避雷器监测结果来分析避雷器存在的问题。