防止距离III段保护因过负荷误动方法的分析与改进

摘要

Research on the scheme to prevent zoneIII distance protection from incorrect operation caused by non-fault overload—the power flow transferring identification method based on DC sensitivity factors is carried out. According to the features of transfer power flow sensitivity factors matrix, the disadvantage of this scheme is proposed which may identify incorrectly due to the only criterion of active power when fault occurs. In order to improve its performance, the criterion of impedance angle is put forward. The concept of power flow transferring characteristics (PFTC) is introduced and is applied to the improved flow transferring identification scheme. The improved scheme can identify non-fault overload reliably and block zoneIII distance protection to prevent cascading trips effectively. The simulation results of IEEE 10-machine 39-bus system have proved its superiority and practicality. This work is supported by National Natural Science Foundation of China (No. 50777016) and Fundamental Research Funds for the Central Universities (No. 12MS110).%深入研究了防止距离III段保护因过负荷误动作的方法——基于转移潮流灵敏度因子的潮流转移识别方案。在归纳转移潮流灵敏度因子矩阵特征的基础上，指出了该方案仅依靠有功潮流判据可能导致故障和过负荷误判断的缺陷，深入分析了错误产生的原因。补充了阻抗角附加判据以改善原有方案的性能，引入潮流转移特征量的概念并应用于提出的改进方案。该方案在发生潮流转移过负荷时能可靠闭锁距离III段保护，有效预防连锁跳闸。对新英格兰10机39节点系统的仿真结果验证了改进方案的优越性和实用性。