针对一起变电站铸造铝合金接线板开裂事件，从其化学成分、力学性能、显微组织、断口形貌、结构设计等多方面出发，综合分析了接线板开裂原因并提出防范措施，以避免同类事故的重复发生。结果表明：失效铝合金接线板中铁元素含量高于标准ZL108铝合金的，基体组织中有大量脆性β（Al-Fe-Si）相及孔洞缺陷，显著降低了材料的力学性能；接线板结构设计不合理导致垂直板与底板交界处形成应力集中，在含氧、硫的腐蚀介质作用下产生应力腐蚀开裂，服役过程中铝合金与电容式电压互感器（CVT）钢板通过腐蚀介质接触发生电偶腐蚀，使铝合金强度进一步降低，加速了裂纹的扩展，最终导致接线板断裂。

The causes of terminal board cracking in a substation were analyzed comprehensively from the aspects of chemical composition, mechanical property, microstructure, fracture morphology and structural design. And preventive measures were proposed to avoid the recurrence of similar accident. The results show that the content of iron in the failed aluminum alloy terminal was higher than that in the standard aluminum alloy ZL108. A lot of brittle β phases (Al-Fe-Si) and hole defects existed in the microstructure of substrate, which significantly reduced the mechanical strength of the material. The unreasonable design of the terminal board structure caused stress concentration at the junction of vertical plate and bottom plate. And stress corrosion cracking was induced with cooperation of the oxygen and sulfur corrosion medium. The galvanic corrosion between the aluminum alloy and the capacitive voltage transformer (CVT) steel plate occurred through corrosive medium during service, which further reduced the strength of the aluminum alloy, accelerated the crack propagation, and finally led to the terminal board fracture.