多端纵联差动保护突变量数据自愈同步算法

Mutation Data Self-healing and Synchronization Algorithm for Multi-terminal Longitudinal Differential Protection

为了消除采样值在数据链路中的延时误差对纵联差动保护装置的影响,本文提出一种基于突变量的保护数据自愈同步算法。首先实时计算各端采样数据的突变量,当超过突变量阈值时,判定多端系统发生短路故障。然后根据采集的电流波形的突变特征计算出各端数据的故障突变时刻,再以某一端的故障时刻为基准,自动补偿其他端与该端之间的时间差,形成新的采样序列,采用重新同步后的采样序列计算故障后差动电流和制动电流值以确保保护装置正确动作。通过理论分析和算例仿真,验证了本算法的正确性和有效性,且本算法有利于提高智能保护装置动作的可靠性,可实现多侧差动和广域差动等原理保护。

To eliminate the influence of time delay of the sampling values in the data link on a longitudinal differential protection device,a protection data self-healing and synchronization algorithm based on mutation is put forward in this paper.First,the mutations of sampling data at multiple terminals are calculated in real time,and when the mutations are larger than the threshold,it can be determined that a short-circuit fault has occurred in the multi-terminal system.Then,according to the mutation characteristics of the sampled current waveform,the fault time of every terminal is cal?culated;based on the fault time at one terminal,the automatic compensation for the time differences between this termi?nal and others are realized,thus a new sampling sequence is formed.The resynchronized sampling sequences are used to calculate the differential current and braking current after fault to ensure the correct action of the protective device.Through theoretical analysis and simulations of a numerical example,the correctness and effectiveness of the proposed algorithm are verified;in addition,it is shown that this algorithm can improve the reliability of actions by the intelligent protection device,thus realizing protections such as multi-terminal differential,wide-area differential,etc.