中压电网容性电流测试方法的研究

发布时间：2018-01-27 03:07

本文关键词： 配电网容性电流信号注入法 IIR滤波器　出处：《西安科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,随着负荷密度区配电网规模的扩大和电缆线路的大量应用,配电网对地容性电流达到一个较高的水平。当配电网发生单相接地故障时,故障点流过过大的容性电流,导致故障点易于产生电弧,进而引起弧光过电压,弧光过电压会引起线路绝缘薄弱处损坏。在配电网中,当容性电流超过规定值时,为了使故障接地点电弧迅速熄灭,避免事故的扩大,需在配电网的中性点装设消弧线圈。因此,为了减小配电网容性电流的危害,确定配电网的运行方式,确定是否需要安装消弧线圈及确定消弧线圈的容量,准确的测量配电网的容性电流是十分必要的。深入研究现有的配电网对地容性电流测量方法,并对各种测量方法进行了仿真,分析各种测量方法的测量精度、适用范围和优缺点。最终采用具有较多优点的注入信号向量法,进行进一步深入研究。对向量法注入信号的选择进行深入研究,研究表明合理地选择注入信号的强度和频率可减小测量误差,并最终确定选择注入“一高一低”的频率。其次,在仿真环境中搭建含有自噪声、电弧炉和变频器模型的不对称系统,仿真分析非线性负荷、系统不对称等对注入信号向量法的影响。最后,对注入信号向量法的信号提取进行研究,设计IIR滤波器,从含有噪声、50Hz工频干扰的信号中提取信号,仿真结果表明IIR滤波器能准确提取信号,能使容性电流测量结果具有较高的精度。
[Abstract]:In recent years, with the expansion of distribution network size in load density area and a large number of applications of cable lines, the distribution network capacitive current to the ground reaches a higher level, when the single-phase grounding fault occurs in the distribution network. Fault points flow too large capacitive current, which leads to the fault point easily produce arc, and then cause arc over-voltage, arc over-voltage will lead to the line insulation weak damage, in the distribution network. When the capacitive current exceeds the specified value, arc suppression coils should be installed at the neutral point of the distribution network in order to extinguish the arc at the fault location quickly and avoid the expansion of the accident. Therefore, in order to reduce the harm of the capacitive current in the distribution network. Determine the operation mode of the distribution network, determine whether it is necessary to install the arc suppression coil and determine the capacity of the arc suppression coil. It is very necessary to measure the capacitive current of distribution network accurately. The existing methods of measuring capacitive current of distribution network to ground are deeply studied, and various measuring methods are simulated, and the measuring accuracy of various measuring methods is analyzed. Application range, advantages and disadvantages. Finally, the injection signal vector method with many advantages is used to further research. The selection of vector injection signal is studied deeply. The results show that selecting the intensity and frequency of the injection signal reasonably can reduce the measurement error, and finally determine the frequency of injection "one high and one low". Secondly, the self-noise is built in the simulation environment. The effects of nonlinear load and system asymmetry on the injection signal vector method are simulated and analyzed. Finally, the signal extraction of the injection signal vector method is studied. The IIR filter is designed to extract the signal from the signal with 50 Hz power frequency interference. The simulation results show that the IIR filter can extract the signal accurately and make the capacitive current measurement results have higher accuracy.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM933.1

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