基于矢量匹配法和遗传算法的频变输电线模型

发布时间：2018-03-07 19:22

本文选题：矢量匹配　切入点：遗传算法　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：当今电力系统的运行中大多数事故都是由操作过电压引起的,为了仔细分析研究过电压过程,避免过电压现象产生的危害,建立精确的频变输电线路电磁暂态模型极其重要。本文详细地介绍了频变输电线路暂态模型的建立过程,表明了建模关键在于对输电线特性导纳和传输函数的有理近似的精确度上。目前应用矢量匹配法对两者进行迭代匹配所得结果较之前提出的方法更为精确。但该方法的缺点为匹配结果受随机初始极点的影响较大。如果初始迭代极点选择不当,将会影响拟合结果的精确度并且严重影响该方法的收敛速度。为了避免矢量匹配法建立的频变输电线暂态模型易受初始迭代极点的影响,论文提出了一种将矢量匹配法与遗传算法相结合的频变输电线等值电路建模方法。借鉴生物界进化理论,利用遗传算法的全局寻优能力搜索全局最优极点。通过构造迭代极点的适应度函数,对矢量匹配过程中出现的迭代极点群体实施遗传操作,力求快速获取具有全局最优的特性导纳、传输函数的近似有理式。同时,为保证近似有理式的稳定性,采用线性约束最小二乘法实施参数拟合。并将该方法实现于仿真平台上,经过实践比较,该方法构建的频变输电线暂态模型有较高的仿真精度,并且将遗传算法和矢量匹配法相结合的这种寻优过程比单纯用遗传算法寻优收敛速度快得多,证实了该模型的实用性。
[Abstract]:Nowadays, most accidents in power system are caused by operating overvoltage. In order to study overvoltage process carefully and avoid the harm caused by overvoltage phenomenon, It is very important to establish an accurate electromagnetic transient model of frequency transformer transmission line. This paper introduces in detail the process of establishing the transient model of frequency transformer transmission line. It is shown that the key to modeling lies in the accuracy of rational approximation of transmission line characteristic admittance and transmission function. The results obtained by using vector matching method are more accurate than those of the previous method. The disadvantage of the method is that the matching results are greatly influenced by the random initial poles. The accuracy of the fitting results will be affected and the convergence rate of the method will be seriously affected. In order to avoid the transient model of frequency transformer transmission line established by vector matching method is vulnerable to the influence of initial iterative poles. In this paper, a method for modeling equivalent circuit of frequency transformer transmission line is proposed, which combines vector matching method with genetic algorithm. The global optimal pole is searched by using the global optimization ability of genetic algorithm. By constructing the fitness function of the iterative pole, the genetic operation of the iterative pole population in the process of vector matching is carried out. In order to ensure the stability of the approximate rational formula, the linear constrained least square method is used to implement parameter fitting, and the method is implemented on the simulation platform. Through practical comparison, the transient model of frequency transformer transmission line constructed by this method has high simulation accuracy, and the optimization process which combines genetic algorithm and vector matching method is much faster than that using genetic algorithm alone. The practicability of the model is verified.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM75;TM743

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