基于差动保护的多端新能源场站T接线路纵向故障判别方法

Longitudinal Fault Identification Method of Multi-Terminal Renewable Station T-Connection Line Based on Differential Protection

中文关键词:新能源场站  T型连接系统  断线故障

keywords:renewable energy stations  T-connection system  open-circuit fault

中文摘要:由于导线连接形式和一次设备的不同，T接线路相比直连传输线路更容易发生纵向断线故障，在新能源场景下，纵向故障的判别受新能源特性约束。首先，阐述了序电流判别方法应用于新能源场景中的局限性，并结合复合序网络连接图分析了故障电气量；其次，以新能源场站零序阻抗特性稳定为条件，设计故障相两端的零序电压差的幅值作为动作判据，零序电压与零序电流的相位差作为方向判据，进而提出了一种针对多端新能源T接场景的纵向故障判别方法；最后，基于专业仿真软件，验证了所提方法在不同负载工况下的有效性。所提方法对数据通道资源的消耗较低。

Abstract:Due to the differences in conductor connection modes and primary equipment，T-connected transmission lines are more prone to longitudinal open-circuit faults than directly connected transmission lines. However，the applicability of traditional methods for identifying longitudinal faults is restricted by the characteristics of new energy sources in new energy scenarios. To this end，first，the limitations of the sequence current identification method applied in new energy scenarios are elaborated，and the fault electrical quantities are analyzed according to the connection diagram of the composite sequence network. Second，on the premise that the zero-sequence impedance characteristics of new energy stations remain stable，the amplitude of the zero-sequence voltage difference at both ends of the fault phase is designed as the action criterion，and the phase difference between zero-sequence voltage and zero-sequence current is taken as the direction criterion；accordingly，a longitudinal fault identification method for the multi-terminal new energy T-connection scenario is proposed. Finally，based on professional simulation software，the effectiveness of the proposed method under different load conditions is verified，and it is also verified that the method has low consumption of data channel resources.