针对变电站构架避雷针普遍出现锈蚀失效这一现象，采用扫描电镜、离子色谱、X射线衍射及电化学测试等手段，观察了避雷针的腐蚀形貌，分析了锈样成分，考察了其电化学特性，进而剖析避雷针的腐蚀过程及失效原因。结果表明：避雷针外壁腐蚀轻微，但中空的内壁发生严重锈蚀，腐蚀破坏是由内向外发展的。雨水由焊接缺陷点渗入且不易排出，导致避雷针内壁长时间处于潮湿环境，是诱发内壁基材高速腐蚀的主因；而生成的Fe₃O₄锈层具有大阴极作用，可促进基体腐蚀，从而进一步加快了内壁失效速率。避雷针腐蚀失效集中于内壁，具有很强的隐蔽性，需引起足够重视。

In order to solve the corrosion failure problem of lightning rod in a transformer substation, scanning electron microscopy, ion chromatography, X-ray diffraction and electrochemical tests were used to observe the corrosion morphology of the lightning rod and to analyze the rust components and their electrochemical properties. The results showed that the outer wall of the lightning rod was slightly corroded, but the inner wall of the hollow lightning rod was seriously corroded, and the corrosion damage developed from the inside to the outside. Rainwater infiltrated into welding defects and could not be easily discharged, resulting in the inner wall of the lightning rod being in a damp environment for a long time, which was the main cause of the high-speed corrosion of the inner wall substrate. Fe₃O₄ rust layer had a large cathodic effect and could promote corrosion of the matrix, further accelerating the inner wall failure rate. Corrosion failure of lightning rod was focused on the inner wall with strong concealment, where enough attention should be paid.