摘要
电缆-架空线混合线路的故障测距存在2个难点:电缆依频特性突出,波头不易准确捕捉;线-缆接头处波阻抗不连续,行波发生反射,增加了故障点反射波识别的难度。分析了电缆-架空线混合线路不同区段故障时,连接点处的负序电流分布特征,提出了一种电缆-架空线混合线路的故障测距新方法。对确定的电缆-架空线混合线路,于故障附加负序网络利用线路两端电气量推导线缆接头处的分布电流,藉此判断故障区段;此后,根据确定的线-缆长度所对应的行波折反射规律,剔除线缆接头处的反射波干扰;根据电流线模分量与零模分量模极大值的极性规律确定故障点反射波,实现电缆-架空线混合线路的单端故障测距。同时,揭示了线路发生单相接地故障的模量耦合现象与规律。大量电磁暂态仿真表明,不对称接地故障存在线模与零模耦合,该电缆-架空线混合线路的故障测距方法有效。
There are two difficulties in fault locating of hybrid transmission system with cables and overhead lines： the traveling wave extraction because of the frequency - dependent characteristics of power cables and the reflecting wave identification because of the discontinuous impedance. The characters of the negative- sequence current at joints are analyzed for faults in different sections and a new fault locating method is presented for hybrid transmission lines. The faulty section is identified according to the distribution of additional negative-sequence current at joints;the disturbance on reflecting wave at joints is eliminated based on the refraction law of lines with fixed length;and the reflecting wave is detected by the polarity of aerial or ground modal maximums. The single terminal fault locating of hybrid transmission lines is thus realized. The phenomena and disciplinarian of coupling between the aerial and ground modes are indicated. Electromagnetic transient simulations show the existence of aerial- ground mode coupling and the validity of this fault locating method.
出处
《电力自动化设备》
EI
CSCD
北大核心
2008年第10期1-7,共7页
Electric Power Automation Equipment
基金
国家自然科学基金资助项目(90610024
50467002
50347026)
云南省科技攻关项目(2003GG10)
云南省自然科学基金项目(2005F0005Z
2004E0020M
2002E0025M)~~
关键词
电缆
架空线
故障测距
行波
小波变换
power cable
overhead line
fault locating
traveling wave
wavelet transform
