高压直流接地极过压保护反事故措施的仿真研究

RTDS based Study on the Anti-Fault Strategies of HVDC Electrode Over-Voltage Protection

利用RTDS仿真系统分析了高肇直流输电系统"4·2"双极相继闭锁事故原因,指出现有接地极过压-开路59EL保护的设计逻辑存在缺陷,在中性母线开关跳开的情况下会出现不合适的动作出口,导致双极相继闭锁事故。通过仿真验证了拉开极线高压侧隔离开关隔离极线可以有效消除在中性母线上耦合的过电压;在中性母线开关跳开后通过合理增加59EL保护延时同时隔离故障极线路是针对"4·2"双极闭锁事故的有效反事故措施。

The ＂4·2＂one-by-one bipolar block fault of Gaopo-Zbaoqing HVDC is analyzed with the RTDS simulation system, and it is argued that there is a logic defect in the design of 59EL （the electrode over-voltage protection）. Due to the logic defect, the 59EL will be tripping incorrectly in the case of the HSNBS （High Speed Neutral Bus Switch） opening, resulting in the one-by-one bipolar block. Simulations in this paper validate that the over-voltage can be removed effectively by isolating the fault pole after the HSNBS opening, and thus an effective anti-fault strategy for the ＂4·2＂ fault is to properly increase the delay time of 59EL after the tripping of HSNBS and to isolate the fault pole at the same time.