Stressed power system conditions such as power swing, voltage instability and load encroachment may influence the secure operation of conventional backup protection at their third zone (zone 3). In this paper, a new integrated backup protection algorithm for distance relay is proposed based on wide-area measurements to distinguish the fault-stress conditions in the presence of offshore wind farm (WF). Presence of WF creates problem for distance relay due to varying wind speed and wide fluctuations in voltage and current signal during fault condition. In this work, two criteria are proposed to analyze and to identify the events. The first criterion compares the positive-sequence bus voltages in order to identify the faulty bus. According to second criterion, the absolute positive-sequence impedance angle difference between the lines connected to that faulty bus is computed to identify the faulty line. Numerous test cases with the WSCC 3-machine, 9-bus and IEEE 39 bus power system models have been simulated using EMTDC/PSCAD software. Results for different fault cases, power swing, load encroachment and voltage instability, and various non-fault cases like capacitor switching, demonstrate the efficacy of the wide-area backup protection scheme. Comparative assessment reports with the existing methods are also presented.

诸如电力摆幅，电压不稳定性和负载侵害之类的紧张电力系统状况可能会影响常规备用保护装置在其第三区域（区域3）的安全运行。本文提出了一种基于广域测量的距离继电器集成备份保护新算法，以区分存在海上风电场的故障应力条件。由于风速的变化以及故障情况下电压和电流信号的较大波动，WF的存在给距离继电器造成了问题。在这项工作中，提出了两个标准来分析和识别事件。第一个标准比较正序母线电压，以识别故障母线。根据第二个标准，计算连接到该故障总线的线路之间的绝对正序阻抗角度差，以识别故障线路。使用EMTDC / PSCAD软件对WSCC 3机，9总线和IEEE 39总线电源系统模型的大量测试案例进行了仿真。针对不同故障情况，功率摆幅，负载侵入和电压不稳定以及各种非故障情况（例如电容器切换）的结果证明了广域备用保护方案的有效性。还介绍了与现有方法的比较评估报告。以及电容器切换等各种非故障情况，证明了广域备用保护方案的功效。还介绍了与现有方法的比较评估报告。以及电容器切换等各种非故障情况，证明了广域备用保护方案的功效。还介绍了与现有方法的比较评估报告。