2010年12月，兴仁换流站发生了一起由于阀冷控制保护逻辑设计缺陷造成的直流系统强迫停运的恶性事件。为避免类似事件的发生，对云广特高压阀冷控制保护逻辑进行了排查，取消了“冗余的2个传感器均故障跳闸”逻辑，提高了云广特高压直流系统运行的可靠性。

A forced outage incident of the DC system had happened in xingren convertor station, due to a logic defect in valve cooling control and protection system, on December 10, 2010. In order to avoid similar accidents, this paper deeply analyzed all the valve-cooling control protection logic in Yunnan-Guangdong UHVDC transmission project. An improvement for protection logic was proposed, which was to cancel the fault trip logic for two redundant sensors. The result shows that the reliability of Yunnan-Guangdong UHVDC transmission project is greatly increased.