基于特定频率电流波形特征的高压直流线路故障判别方法  

A Fault Identification Method for HVDC Transmission Lines Based on Waveform Characteristic of Specific Frequency Current

作　　者：刘剑[1] 邰能灵[1] 范春菊[1] 陈实[1] 

机构地区：[1]电力传输与功率变换控制教育部重点实验室(上海交通大学),上海200240

出　　处：《电工技术学报》2017年第1期20-31,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51377104;51407115);中国博士后科学基金(2014M560333)资助项目

摘　　要：为提高高压直流线路故障判别的可靠性,提出了一种高压直流线路单端故障判别方法。通过分析直流滤波环节的阻抗特性,选取特征谐波电流,并分析其波形特征。直流线路区内、外故障时,特征谐波电流的波动特性差异明显,据此形成直流线路故障判据。利用方差值与均值之比,即波动系数来描述电流波形的波动大小。直流线路的故障判别仅需通过计算特征谐波电流的波动系数来实现。该故障判别方法原理简单、可靠,不受系统参数及干扰的影响。对比分析显示,该故障判别方法能有效克服传统故障判别方法中仅利用单次暂态谐波幅值和频带暂态电气量进行故障识别的可靠性低和易受干扰的缺陷,并在采用较少判据的情况下,仍具有较高的可靠性。大量仿真结果表明,该故障判别方法能可靠、快速地区分直流线路区内、外故障,且能实现故障选极。A novel sing-end fault identification method is proposed to improve the reliability of fault identification for high voltage direct current （ HVDC） transmission lines. The characteristic harmonic current is selected by analyzing impedance of DC filter units. The difference of fluctuations in the harmonic current is significant when internal and external faults appear on the DC l ine, which is used for fault identification. In order to describe the fluctuations, the ratio of variance and mean of current samples are identified as fluctuation coefficient, because the faults on the direct line can be achieved by just calculating the fluctuation coefficient of the Characteristic harmonic current. The fault identification can be achieved easily. The proposed method is simple and reliable without the influence of system parameters and interference. Compared with some previous methods using values of single frequency or band electrical quantities and suffering some shortcomings like low reliability on fault identification and low stability on anti-interference can be overcame by employing the proposed method, and this method has higher reliability with fewer criterions. A lot of simulation results show that the proposed method is able to identify internal and external faults of a DC line area reliably and rapidly, and this method can also realize the fault pole selection.

关 键 词：谐波电流 波动系数 阻抗特性 方差 故障判别 

分 类 号：TM773[电气工程—电力系统及自动化]