基于杰卡德相似度一体化判据的柔直线路纵联保护

基于双端法的柔直线路纵联保护通讯量大、动作时间长，并且受噪声干扰等因素影响较大，致使其整定困难。基于此，提出了一种基于杰卡德相似度一体化判据的柔直线路纵联保护方法。首先分析了柔直线路区内外故障电压电流变化率的故障特征，并分别构建了模拟量至逻辑量的转换关系，进而提出基于0.5ms数据窗下逻辑量比较的杰卡德相似度模型，基于区内故障的高相似度构建一体化判据实现故障类型的判别，无需故障启动及故障选极判据。最后双端基于逻辑量比较的纵联保护方案，实现柔直线路的快速保护，该保护方法原理简单，动作速度快，易于实现。利用PSCAD/EMTDC搭建的四端柔直输电系统模型，分别验证了区内外不同故障类型、高阻接地、噪声干扰等多种场景下的保护有效性。

Pilot protection of flexible DC line based on Jaccard similarity integration criterion

The flexible line protection based on the double-ended method has a large amount of communication and a long action time, and is greatly affected by factors such as noise, which makes it difficult to set. Based on this, a pilot protection method of flexible DC line based on jaccard similarity integration criterion is proposed. The fault characteristics of the change rate of fault voltage and current inside and outside the flexible line area are analyzed, and the conversion relationship between analog quantities and logical quantities is constructed respectively, and a Jaccard similarity model based on the comparison of logical quantities under the 0.5ms data window is proposed. The integrated criterion is constructed with high similarity to realize fault type identification, and no fault start and fault pole selection criteria are required. Finally, the double-ended longitudinal protection scheme based on the comparison of logical quantities realizes the rapid protection of the flexible line. The protection principle is simple, the action speed is fast, and it is easy to implement. Using the four-terminal flexible straight model built by PSCAD/EMTDC, the protection effectiveness in various scenarios such as different fault types, high-resistance grounding, and noise interference inside and outside the zone were verified.