中文摘要：

现行输电线路的故障类型和故障性质判别均依据线路中电气量的变化特征被动判断，对于某些线路运行状况，往往因缺乏主动性而造成保护误动或拒动。针对这个问题，借鉴纵差保护输电线载波通信技术，分析高频信号在输电线路各种故障时的传播特性，提出了一种基于高频信号的输电线路主动式保护。该保护通过向输电线路发射高频信号，主动判断输电线路的故障类型和故障性质。仿真验证结果表明，这种输电线路主动式保护可以准确判断出输电线路中各种类型的故障，并通过延时循环判断，可靠区分瞬时性故障和永久性故障。

英文摘要：

Existing transmission line fault type and characteristic distinguishing methods are all based on variation features of electrical quantities passively, on some operation conditions, mal-operations or miss-operations are caused frequently because of lacking initiative. By drawing from power line carrier communication technology of longitudinal differential protection, and through analysis on transmission characteristics of high-frequency signal under various types of transmission line faults, an active protection scheme of transmission line based on high-frequency signal is proposed. The proposed protection scheme can distinguish fault type and characteristic actively by emitting high-frequency signal to transmission line. Results of simulation show that different types of faults can be detected by the proposed active protection scheme accurately, and through delayed cycle-judgment, temporary faults can be distinguished from permanent ones reliably.