介绍了换流变和平波电抗器非电量保护配置情况。对近年来发生的由换流变和平波电抗器非电量保护动作导致的直流闭锁事件进行了统计，分析了换流变和平波电抗器非电量保护动作原因并提出整改建议。研究了换流变和平波电抗器非电量保护防误动的措施，从而进一步提升直流输电系统的运行可靠性。

The configurations of nonelectrical protection for converter transformer and smoothing reactor are introduced. The DC blocking accidents occuring in recent years due to nonelectrical protection for converter transformer and smoothing reactor are presented. The reasons are analyzed and the improvement measures proposed for further enhancing the reliability of the HVDC transmission system.