中文摘要：

研究表明线路分布电压、电流经过相同的线性电路传变后，其相互关系仍符合原线路分布参数模型，工频附近的电压信号在线路上接近线性分布。在此基础上，提出一种用于远距离输电线路保护的等传变瞬时值差动保护方法，该方法从线路一次电气量到用于差动保护计算的瞬时值，电压和电流经过的传变环节基本相同。首先将电流采样值经虚拟数字CVT处理，然后对电压和电流采样值通过相同的低通滤波处理。由线路电压瞬时值分别实时计算出流入并联电抗器和流入线路Ⅱ型等值电路两侧电容的电流瞬时值，再从线路每侧电流除去这两部分电流，用得到的新电流瞬时值作常规采样值差动和故障分量采样值差动保护计算。ATP仿真表明，等传变瞬时值差动保护可靠性高、动作速度快、耐过渡电阻能力强、具有选相能力。

英文摘要：

It is revealed that the interaction between transient voltage and current still satisfies a uniform transmission line＇s distributed parameters model after distributed voltage and current pass through the same linear circuit. The distribution of voltage is a liner function along the transmission line when its frequency is near power frequency. On the basic of the analytical results, a new scheme of long transmission line current differential protection by using instantaneous value after equal transfer processes was presented. The voltage and current have equal transfer processes from primary electrical quantities to instantaneous values used by differential protection. At first the current sampling values pass through virtual digital CVTs. And then the voltage and current sampling values are processed by a low pass filter. According to the instantaneous value of transmission line voltage, the current instantaneous values of shunt reactors and 17 equivalent circuit capacitance can be calculated. After removing these two kinds of current, sampling value differential protection based on all components and fault component can be applied. The results calculated by ATP show that the proposed technique has highly reliability, a short operation time, excellent performance under high-resistance earth-fault conditions and phase selection ability.