T接线路行波差动保护

由于传统的行波差动保护无法应用于T接输电线路，文中研究了一种新的行波差流表达式，理论推导了其在区内故障时的差流特征。为有效躲过线路空充等各种运行工况和区外故障引起的暂态不平衡行波差流，引入电流行波制动量，提出一种具有轻微比例制动特性的行波差动保护实用方案，在区内高阻故障时能够保持很高的灵敏度。理论分析及EMTP仿真计算表明，该方案灵敏度高，动作速度快，对装置采样和通信速率没有过高的要求，能够在现有技术条件下实现，具有较高的实用价值。

Traveling-wave Differential Protection on Teed Transmission Lines

Since the traditional traveling-wave differential protection cannot be applied to Teed transmission lines, this paper presents a novel traveling-wave differential current expression. The characteristics of differential current at the internal fault state are studied. The restraint traveling-wave is introduced to avoid transient unbalance of differential current under all kinds of operation conditions. Accordingly this paper describes a new scheme with little percentage-ratio restraint characteristic based on traveling-wave differential protection. It also retains high sensitivity for internal high-resistance fault. Theoretical analysis and EMTP simulation show that the scheme operates sensitively and rapidly. Besides, it is realizable and applicable using currently available technique, for it has no special demands on the sampling rate and transmission speed.