LCC-VSC混合直流输电线路的组合型单端故障定位方法  

Combined Single-end Fault Location Method for LCC-VSC Hybrid HVDC Transmission Line

作　　者：张艳霞[1] 王海东[1] 李婷[1] 林志海 常雨晴 ZHANG Yanxia;WANG Haidong;LI Ting;LIN Zhihai;CHANG Yuqing(Key Laboratory of the Ministry of Education on Smart Power Grids,Tianjin University,Tianjin 300072,China)

机构地区：[1]智能电网教育部重点实验室天津大学

出　　处：《电力系统自动化》2019年第21期187-194,共8页Automation of Electric Power Systems

摘　　要：电网换相换流器-电压源换流器(LCC-VSC)混合直流输电线路中的故障行波传播特性有别于常规直流和柔性直流的输电线路。文中针对混合直流输电线路分析了行波折反射过程及两端边界反射角的频变特性,确定了单端法故障定位装置的合理安装侧,提出了一种组合型单端故障定位新原理。首先,利用定位精度略低的固有频率法进行故障位置初测,以此粗略计算故障点第1次反射波的大致到达时刻。然后,再利用故障点反射波与对端母线反射波的波到达时刻的对称性质在行波传播时序图中匹配找到这2种反射波的精准波到达时刻。最后,根据初始行波、故障点第1次反射波和对端母线第1次反射波到达时刻实现故障定位。仿真实验表明,固有频率法的引入有效避免了由于无法准确区分故障点第1次反射波与对端母线第1次反射波所带来的定位误差,所提方法在LCC-VSC混合直流输电系统中能实现较准确的故障定位。The propagation characteristics of fault traveling wave on line commutated converter-voltage source converter(LCC-VSC) high voltage direct current(HVDC) transmission line are different from those line commutated converter based HVDC(LCC-HVDC) or voltage source converter based HVDC(VSC-HVDC) transmission lines. Aiming at LCC-VSC HVDC transmission line, the refraction and reflection processes of traveling wave and the frequency-variation characteristic of the reflection angles at both boundaries of lines are analyzed, the reasonable installation side for the single-end fault location device is determined, and a novel location principle of combined single-end fault is proposed. Firstly, the location method of natural frequency fault whose accuracy is slightly lower is utilized to roughly locate the fault point and obtain approximate arrival time of the first reflected wave from the fault point. Then, based on the symmetry between the arrival time of the reflected wave head from the fault point and that from the opposite bus of line, the precise arrival time of these two reflected waves are found by matching in traveling wave propagation sequence diagram. Finally, the fault point is accurately located with the arrival times of the initial traveling wave, the first reflected wave from the fault point and that from the opposite bus of line. The simulation results show that the introduction of the natural frequency method effectively avoids the location error caused by the inaccurate discrimination between the first reflection wave from the fault point and that from the opposite bus of line, and the proposed method can accurately locate the fault point on the transmission lines of the LCC-VSC HVDC system.

关 键 词：电网换相换流器-电压源换流器 混合直流输电 单端行波故障定位方法 固有频率 波头识别 

分 类 号：TM7[电气工程—电力系统及自动化]