The characteristics of inter-line faults and the protection responses of parallel lines transmission system considering weak-infeed effect are analyzed. Due to the weak-infeed effect, phase selection element may not function in the synonym phase inter-line faults, which would cause the parallel transmission lines three-phase trip at the same time and bring about the terminal substation loss-of-voltage accident. The response characteristics of fiber differential protection and pilot distance protection using split-phase command under different faults condition are analyzed, and protection measures to avoid the incorrect phase selection in the inter-line faults are proposed. To improve phase selection reliability, the main protection scheme is presented. Finally, the effectiveness of proposed protection scheme is verified by RTDS simulation experiment based on the actual line parameters and protection apparatus.%研究了带弱馈系统的同杆线路跨线故障的电气特征和保护响应特性,在异名相跨线故障时由于弱馈端电源支撑不足,非故障相反向电流穿越等原因可能造成保护选相失败,进而导致同杆线路同时三跳,引起终端变电站失压而损失大量负荷.分析了光纤差动保护和传输分相命令的纵联距离保护在不同故障条件下的响应特性,给出了跨线故障下保护误选相的处理措施,提出了提高选相可靠性的主保护配置方案.基于实际线路参数和主流厂家保护进行的RTDS仿真试验论证了保护方案的有效性.
展开▼
