基于多维度相互校验的线路电流差动保护自校正同步策略

Multi-dimensional Cross-checking Based Self-correcting Synchronization Strategy for Line Current Differential Protection

针对目前线路电流差动保护普遍使用的基于内部时钟同步方法,分析了基于乒乓原理测量通道时延的内部时钟同步方法在出现通道路由不一致时,会造成差动保护不正确动作的可能性。提出了一种自适应的异常差流监视手段,同时结合线路两侧的电气量同步判据,能够可靠识别出线路电流差动保护同步异常的情况。在内部时钟同步的基础上,提出了一种结合电气量判据及外部时钟的自校正同步策略,该策略能够自动完成同步状态辨识,提高了差动保护抗通道收发路由不一致的能力。实验验证表明,所提出的基于多维度相互校验的电流差动保护自校正同步策略能够提高线路电流差动保护抗通道扰动的能力。

In view of the inner-clock synchronization method normally used in the line current differential protection,the possibility of differential protection mal-operation is analyzed when there is an inconsistence of the sending and receiving routing in measuring the channel delay based on the Ping-Pong theory. By combining the synchronization criteria of the electrical variables on both sides of the line,an adaptive abnormal differential current monitoring method is proposed for identifying the synchronization abnormality in the line current differential protection. A self-correcting synchronization strategy is then given which combines the inner-clock system,external clock system and electrical variables criteria. The strategy is able to automatically realize the synchronization status identification and improve the capability in solving the routing inconsistency of differential protection. Testing results show that the proposed multidimensional cross-checking based self-correcting synchronization strategy can increase the robustness of line differential current in the routing inconsistency situation.