穗东换流站交流滤波器保护误动作分析及改进措施

云广直流输电系统穗东换流站在调试、运行期间,多次发生交流滤波器电容比值不平衡保护跳闸、且两套冗余保护系统动作行为不一致的事故。文章分析了这些事故,发现保护动作行为不一致是由于滤波器不平衡支路上流过过大的冲击电流和保护内部实际延时较短未能躲过冲击所致。针对保护设计不合理之处,提出了保护延时改进措施以预防此类事故,措施的效力已被RTDS试验证实。

Analysis on the AC Filter-Protection's Misoperation and Correlative Improvement Measures at Suidong Converter Station

During the test and operation of Suidong converter station in Yunnan-Guangdong DC transmission project, the faults of capacitor ratio imbalance protection of AC filter tripping and two redundance protection systems being in conflict occurred several times. Analyzing these faults, this paper discovers that the faults were due to the exceeding impact current through the imbalance spur track and the too short time-delay in the AC filter protection to avoid the impact in fact. Aiming at the illogicality of the protection design, correlative improvement measures are proposed to prevent this kind of faults, and the effectiveness of the measures is validated by RTDS simulations.