On the basis of the introduction of commutation failure principle,analysis of commutation failure in Three Gorges-Guangdong HVDC system Echeng station is made according to the transient fault record.

• 在简要介绍换相失败基本原理的基础上,根据现场的暂态故障录波图,对三广直流鹅城换流站发生换相失败的原因进行了详细分析。