距离保护是输电线路故障处理的重要手段之一，而过渡电阻一直是影响其保护性能的重要因素。智能电网中，对端信息易于获取，在原有距离保护投入的基础上，引入对端信息可提高距离保护耐受过渡电阻能力。本文在综述输电线路继电保护研究现状的基础上，提出一种基于双端电气量（电压和电流）距离保护耐受过渡电阻性能改善新方法，旨在解决传统距离保护存在的受过渡电阻变化影响等问题。 本文基于输电线路的1模等值电路，利用发生故障时故障点处电压相等的特点，推导出了某一特定频率下的保护原始方程；接着将保护原始方程中的双曲正、余弦函数展开成泰勒级数，并分别采取三种方法忽略高阶项进行近似，得到三种保护实用方程，利用最小二乘优化算法求解得出故障距离；最后比较三种保护实用方程的故障距离估计准确性，并综合考虑算法的计算量，从中选出最优的一种算法。级数展开与简化计算是本文工作的创新点。 为了利用所提出的新方法实现保护性能改善，在双端电气量数据采集的基础上，需要利用数字带通滤波器滤得暂态信息中的特定频率分量的信息，为此本文研究并设计了一个满足本算法需要的FIR数字带通滤波器。 本文最后选用某地区长度为300km，电压等级为500kV的双端供电的输电线路进行了线路故障EMTP仿真验证，利用MATLAB实现了所提出的保护性能改善新方法。结果表明所提出的新方法原理是可行的，并且不受过渡电阻和系统运行方式变化的影响，具有能够直接反映故障距离的特点。

Distance protection is one of important means for fault handing on transmission line. But fault resistance is an important factor to influence the distance protection performance. The opposite terminal is easy to obtain in smart grid. Based on the original input on distance protection, using the opposite terminal can improve the ability to withstand fault resistance in distance protection. This paper firstly summaries the research of the current situation on transmission line protection, then proposes a new principle to improve the ability to withstand in distance protection which based on double terminal’s electrical information, aiming to solve the problems of the traditional distance protection caused by the exist of the change of transition resistance. The paper is based on 1 mode equivalent circuit of transmission line, derive a ranging equation for protection in a particular frequency according to the characteristic of equal voltage of the point of failure.Then expands the functions of hyperbolic sine and cosine into the Taylor series in equation of distance protection. Then Ignore polynomial of high order to approximate in three methods, we can get three kinds of ranging equations for protection, using least square optimization algorithm to obtain the fault distance. Finally, the most suitable algorithm can be determined by comparing estimation accuracy of the fault distance under the three algorithms and considering the amount of computation algorithms. The Taylor series expansion and simplified calculation is the innovation of this paper. In order to actualize the improvement of protection performance using the principle which is proposed, we need to filtered the information of the specific frequency component in transient according to a Band pass filter. So in this paper a FIR digital band pass filter which meets this algorithm is studied and designed in this paper. Lastly, a double ended power supply system in which transmission line length is 300km and voltage level is 500kV is chosen and simulated in EMTP. Then the new principle of improving the ability to withstand fault resistance in distance protection which is actualized in MATLAB. The simulation results have verified the accuracy of the distance protection principle which is presented. The protection method is not only affected by the change of transition resistance or system operation, but also can directly reflect the fault location.