高压直流输电线路的双端行波频差比值故障测距  

A Novel Fault-location Method for HVDC Transmission Lines Based on the Ratio of Two-terminal Traveling Wave Frequency Difference

作　　者：束洪春[1] 杨竞及 张广斌[1] SHU Hongchun;YANG Jingji;ZHANG Guangbin(Kunming University of Science and Technology,Kunming 650500,Yunan Pronvince,China)

机构地区：[1]昆明理工大学电力工程学院,云南省昆明市650500

出　　处：《中国电机工程学报》2022年第18期6715-6726,共12页Proceedings of the CSEE

基　　金：国家自然科学基金项目(52037003);云南省重大科技专项项目(202002AF080001)。

摘　　要：高压直流架空输电线路通常距离较长、故障率高、电晕损耗大、雷击干扰和谐波干扰严重、线路实际长度有变化,使得对其进行准确的故障测距难度加大。研究发现,线路故障行波或者自由振荡分量自然频率之等间隔频谱的频差与其故障距离具有明确的数学关系,且该频差不受直流输电线路边界条件、不同次频率下的波速不一致等因素的影响。借此提出一种基于双端行波频差比值的高压直流输电线路故障测距方法,消除了波速衰减的影响,实现无需线路两侧时钟同步的双端测距。该方法突破了惯常在时域中对行波波头进行甄别、对行波波到时刻进行标定的瓶颈,原理上,其测距可靠性和精度不受行波色散、雷击电晕、谐波干扰、线长变化等因素影响。大量仿真和现场实录数据验证表明,测距结果精确、方法稳健,对弱故障具鲁棒性;其稳健性和精度不受线路边界元件影响,对高阻故障耐受能力好。High voltage direct current(HVDC) overhead transmission lines have the characteristics of long length, high failure rate, large corona loss, and serious disturbance caused by lightning and harmonic waves;and the true value of line length also varies. As a result, it is more difficult to perform accurate fault locating. The study indicates that both the equal interval frequency difference of the natural frequency spectrum of the fault traveling wave and the free oscillation components have the exact mathematical expression related to the fault distance. And the frequency difference is not affected by the boundary conditions of DC transmission or the inconsistent wave velocity at different sub-frequency. A fault location approach for HVDC transmission lines based on the frequency difference ratio of the two-terminal traveling wave was proposed. The fault locating equation has eliminated the influence of traveling wave velocity’s attenuation, and is independent of two-terminal clock synchronization. The proposed method made a breakthrough in identifying the traveling waves’ wavefront in time domain and precisely calibrating the arrival time of traveling waves. The reliability and accuracy are not affected by traveling wave dispersion,lightning corona, harmonic interference, line length variation or other factors. Massive digital simulation and field data record test show that the proposed method is precise and robust, which is not affected by physical boundary components of the line,and has good tolerance to high impedance faults.

关 键 词：自然频率 频差 高压直流输电 故障定位 行波 输电线路 

分 类 号：TM77[电气工程—电力系统及自动化]