对某500 kV直流输电线路失效的耐张线夹进行了宏观检查、尺寸测量、射线检验以及现场模拟试验，并结合规范对试验结果进行了分析，指出压接工艺不当是线夹断裂的主要原因。该分析对耐张线夹的液压施工以及确保输电线路安全运行具有借鉴意义。

According to the standard, the strain clamp with cracking failure on 500 kV DC transmission line was investigated by the means of macroscopic examination，measured on the margins，ray inspection，chemical analysis and field test. The results show that the main reason of cracking failure is the improper process of pressure contact technique, which presents references for the strain clamp’s hydraulic construction and has significance meaning for the safe operation of transmission lines.