具有方向判别能力的输电线路故障识别办法  

A Fault Identification Method for Transmission Lines with Directional Discrimination Ability

作　　者：虎俊 张智 丁鹂 李富 王栋 于大川 HU Jun;ZHANG Zhi;DING Li;LI Fu;WANG Dong;YU Dachuan(Wuzhong Power Supply Company,State Grid Ningxia Electric Power Co.,Ltd.,Wuzhong 751100,Ningxia,China;Tongxin County Power Supply Company,State Grid Ningxia Electric Power Co.,Ltd.,Wuzhong 751100,Ningxia,China;Qingdao University of Science and Technology,Qingdao 266061,Shandong,China;Chongqing University,Chongqing 400044,China)

机构地区：[1]国网宁夏电力有限公司吴忠供电公司,宁夏吴忠751100 [2]国网宁夏电力有限公司同心县供电公司,宁夏吴忠751100 [3]青岛科技大学,山东青岛266061 [4]重庆大学,重庆400044

出　　处：《电网与清洁能源》2023年第9期106-115,共10页Power System and Clean Energy

基　　金：国网宁夏电力有限公司科技项目(5229WZ21N002);山东省自然科学基金(ZR2020QE213)。

摘　　要：在电力系统中,针对模块化多电平换流器(modular multilevel converter,MMC)的高压直流输电技术目前已经被广泛应用。在一般情况下,MMC-HVDC输电线路通常采用以ABB或SIEMENS技术为核心的行波保护原理来完成主保护,其通过对单端电压、电流行波的变化量或变化率进行检测从而识别故障,因其不具备故障方向识别能力,在发生区外故障的情况时可能会导致误动。同时,为了获取较为明显的行波突变,实际工程中多选择在线路出口安装平波电抗器,这进一步提升了建设成本。据此,提出了一种具有方向判别能力且无需平波电抗器提供边界的MMC-HVDC输电线路纵联行波方向保护原理。分析了MMC-HVDC输电线路行波折射、反射特性,基于行波的瞬时功率提出了故障方向识别判据及故障极识别判据;对±500 kV直流输电系统进行了PSCAD/EMTDC软件建模和仿真。根据所建模型计算出不同故障条件下各参数变化情况,并将计算结果与理论结果和试验数据对比分析。模拟结果表明:所提出保护方法具有方向的判别能力,且不依赖平波电抗器提供边界特性,该保护方法在各因素(如不同故障位置、不同故障电阻及不同故障类型等)的影响下均可可靠地动作。Currently,the high voltage DC transmission technology based on modular multilevel converters is widely utilized in actual power grids.In general,the MMC-HVDC transmission line usually adopts the traveling wave(TW)protection principle with ABB or SIEMENS technology as the core to complete the main protection.Essentially,this protection identifies faults by detecting the changes or rates of single terminal voltage and current traveling waves.Due to its lack of fault direction recognition ability,it may cause misoperation in the event of out-of-zone faults.Besides,in order to obtain TW with obvious mutation features,many actual MMC-HVDC projects choose to install the smoothing reactor on the transmission line outlet,which leads to increased investment.To overcome these shortcomings,this paper proposes a principle of longitudinal traveling wave directional protection for MMC-HVDC transmission lines with directional discrimination capability and without the need for a flat wave reactor to provide a boundary.Firstly,The refraction and reflection characteristics of special traveling waves in MMC-HVDC transmission lines are analyzed.Secondly,the paper proposes a fault direction identification criterion and a fault pole identification criterion based on the instantaneous power of the traveling wave.Thirdly,using PSCAD/EMTDC,a±500kV MMC-HVDC simulation model is constructed.Finally,a series of simulations prove that the new traveling wave protection is not affected by different fault locations,different fault resistances and different fault types.

关 键 词：行波 纵联方向保护 输电线路 瞬时功率 

分 类 号：TM77[电气工程—电力系统及自动化]