半波长交流输电线路三相短路谐振点研究

发布时间：2018-03-25 18:44

本文选题：半波长　切入点：交流输电　出处：《电网技术》2017年09期

【摘要】：半波长交流输电线路三相短路时刻的工频故障特性对线路绝缘、过电压抑制和暂态稳定具有重要影响。通过仿真现象提出研究问题,建立半波长单点送出系统三相短路的电路模型,理论推导短路时刻电流和最严重故障位置的计算公式,理论分析系统产生谐振的机理,研究严重故障点与系统开机台数、线路结构、电压等级的变化规律,研究短路时线路沿线电压的分布和过电压情况,并通过仿真验证理论分析结果。研究结果表明,长于1000km线路在部分长度区间发生短路时刻电流、功率可能激增,引发系统谐振,线路沿线出现严重过电压,需要采取必要的抑制措施;对于线路长度超过1000km的线路,严重故障点除应考虑首端、末端外,还应考虑离首端和末端距离为l=(π-t)/β处。对于常规长度的线路(线路长度小于1000km),不论是1000kV、750kV、500kV,线路沿线发生三相短路,系统不会产生工频谐振现象。线路发生三相短路后沿线电压最大值位于距短路点四分之一波长处;严重故障点位置与送端系统开机台数、接入系统强弱、线路结构、电压等级有关。
[Abstract]:The power frequency fault characteristics of three-phase short circuit of half-wavelength AC transmission line have important influence on line insulation, over-voltage suppression and transient stability. The circuit model of three-phase short circuit of half-wavelength single-point output system is established, the calculation formula of short-circuit moment current and the most serious fault position is deduced theoretically, the mechanism of system resonance is analyzed theoretically, and the serious fault point and the number of system booting are studied. The variation law of circuit structure and voltage grade, the distribution of voltage and overvoltage along the line during short circuit are studied, and the theoretical analysis results are verified by simulation. The results show that, When short circuit occurs in part of the length of 1000km line, the power may surge, cause system resonance, serious overvoltage along the line, need to take necessary measures; for the line length of the line over the 1000km line, The serious fault point should consider not only the first end and the end, but also the distance from the first end to the end ln (蟺 -t / 尾). For the line of normal length (the length of the line is less than 1000kmg, whether it is 1000kV or 750kV or 500kV), the three-phase short circuit occurs along the line. The maximum voltage along the line is located at the wavelength of 1/4 wavelength from the short-circuit point; the position of the serious fault point and the number of power stations of the feeder system, the strength of the access system, the circuit structure, The voltage level is related.
【作者单位】：国家电网公司;中国电力科学研究院;
【分类号】：TM75

【相似文献】