【作者】 刘博；

【导师】 张庆超；

【作者基本信息】 天津大学 ， 电气工程， 2012， 硕士

【摘要】 随着电力系统网络规模的不断扩大,电力系统中不对称运行的现象也越来越普遍,尤其是高压或超高压等长距离输电线路开始大量应用,由于技术和成本等原因,输电线路往往采用不换位的形式,使电力系统的不对称程度增加,对电力系统的稳定运行产生了许多不利的影响。当输电线路不换位时,输电线路的参数不满足循环对称的条件,采用传统的对称分量法不能实现输电线路三相之间解耦计算,即无法使用Fortescue变换将不换位的输电线路参数矩阵进行对角化。而采用相分量法进行故障分析等计算时计算量太大,计算效率不高。故本文应用模分量法对不对称的输电线路进行故障分析和测距等计算,该方法类似于对称分量法,它的计算模型简单,计算量小,基于分布式的线路模型计算结果更为精确。模分量法中的核心是将输电线路的参数矩阵对角化,这点与对称分量法类似,在输电线路不换位条件下,不能使用Fortescue变换矩阵,但是Fortescue矩阵依然对于精确的能使线路参数矩阵对角化的矩阵模型起决定作用。针对这个特点,本文提出了一种新的使参数矩阵对角化的方法,该方法是基于Fortescue变换的矩阵,先直接将不换位的输电线路参数矩阵进行Fortescue变换,得到其相似矩阵后进行近似处理,得到最终的变换矩阵和对角化矩阵,并应用到模分量法中对不换位的输电线路进行故障分析、测距等研究,最后从误差方面分析仿真计算的结果,并与其算法进行对比,验证了该方法在对于输电线路不对称的故障分析计算的可行性,有效的减少了计算量,提高了计算精度。更多还原

【Abstract】 With the power system network developing, the asymmetrical operation of the power system became more and more common, especially the ultra high voltage or high voltage with long distance transmission line has been widely applied. Considering the technique and the cost factors, the high voltage transmission line is often used in the form of untransposed, which increased the unbalance and it has many adverse effects on stable operation of power system. For the fault analysis of asymmetrical three-phase transmission lines, the parameter of transmission line do not satisfied the condition of cyclic symmetry. The symmetrical components method can not be decouple the three-phase transmission line. It means that the Fortescue transformation matrix will not be able to digitalization of the parameter matrices of the transmission line. If using the phase components method, the number of calculation is much larger and the computation efficiency is lower. Therefore, this paper uses the modal analysis for the fault analysis of asymmetric transmission line. This method is much similar to the symmetrical components method. It is much simpler and more accurate.The important step of modal anaylsis is made the parameter matrix of transmission line diagonalization. For the modal anaylsis of asymmetrical three-phase transmission lines, It can not use the Fortescue matrix, but the Fortescue matrix still play an important role in determining the exact modal transformation. To solve such problem, this article introduces a new method which can diagonalize the parameter matrix based on Fortescue transformation by using the properties of the similar matrix of parameter matrix to simplify the calculation process. The corrected transformation matrix we final get will be used in the modal analysis on fault analysis and fault location. The error results from simulations shows that the corrected transformation matrix is feasibility of fault analysis of weak geometry unbalances transmission line.更多还原