含分布式电源的配电网故障定位研究

发布时间：2018-05-05 21:34

本文选题：配电网 + 分布式电源　；参考：《太原理工大学》2017年硕士论文

【摘要】：随着全球能源互联的不断发展,以清洁能源为主的分布式发电由于低污染、低能耗等特点得到了迅速的发展。分布式电源(Distributed Generation简称DG)的接入使得传统配电网由辐射型网络变为了电源和用户互联的复杂多电源网络,使得适用于传统配电网故障定位方法的准确性和适应性降低。研究含分布式电源的故障定位方法对于提高配电网的供电可靠性以及促进分布式电源发展均具有重要意义。根据配电网建设及故障定位发展现状,分析了DG接入对配电网传统故障定位方法的影响,通过调整DG接入点上游各开关定值,使其可以区分系统侧主电源提供的最小正向短路电流和DG提供的最大反向短路电流,以使得传统故障定位方法在含DG的配电网中仍具有一定的适用性;同时分析了DG接入容量过大、供电距离过长时,架空线配电网的故障定位方法;通过算例仿真分析了该开关定值调整策略的可行性和局限性。针对DG接入容量过大和供电距离过长时,传统故障定位方法的局限性,提出了含DG的改进矩阵算法。该算法根据配电网各运行方式下正常潮流流向定义开关正方向,自动修正网络描述矩阵;只根据FTU上传的n?1阶故障信息矩阵快速获得n?1阶故障判断矩阵;根据电网结构特点和基尔霍夫定律,改进T节点区域故障判据;提出了FTU上传信息不完备或畸变等情况下的故障定位方法,提高馈线各区域内的单重故障和多重故障的定位准确度;从而解决了传统矩阵算法需要根据电源数假定多个正方向进行多次故障定位、故障判定规格化处理计算量大、T节点区域故障定位准确率低等问题。通过算例仿真,验证了改进矩阵算法的准确性和容错性。由于配电网实际故障定位时,FTU上传信息易受外界环境,天气等因素的影响而发生畸变,当FTU畸变数较多时,改进矩阵算法容错性大幅降低,针对这种问题,引入遗传算法进行含DG的配电网故障定位。针对DG接入配电网后,传统遗传算法不能适应DG的不同投切情况,造成故障定位准确性和稳定性降低的问题,本文提出一种改进的遗传算法来适应多变的配电网网络结构。该算法通过改进交叉和变异算子加快算法收敛速度并避免陷入局部寻优;通过改进开关函数和适应度函数,使其更好的适应DG的投切,提高故障定位的稳定性和效率;针对大规模配电网故障定位计算速度问题,引入了分级处理思想,加速故障定位的速度。通过算例仿真,验证了改进遗传算法在含DG的配电网系统出现单一故障和多重故障情况下故障定位的有效性,同时针对实际运行中FTU上传信息畸变和丢失的情况,比较了改进遗传算法和传统遗传算法以及改进矩阵算法在不同故障情况下的稳定性、准确性和容错性,算例分析证明了改进遗传算法具有更好的稳定性和容错性。
[Abstract]:With the continuous development of global energy interconnection, distributed generation based on clean energy has been developed rapidly because of its low pollution and low energy consumption. The access of distributed Generation makes the traditional distribution network change from radiative network to complex multi-source network, which makes the accuracy and adaptability of fault location method for traditional distribution network reduced. It is of great significance to study the fault location method with distributed power supply for improving the reliability of distribution network and promoting the development of distributed power generation. According to the current situation of distribution network construction and fault location, the influence of DG access on the traditional fault location method of distribution network is analyzed. It can distinguish the minimum forward short-circuit current provided by the main power supply on the system side and the maximum reverse short-circuit current provided by DG, so that the traditional fault location method still has certain applicability in the distribution network containing DG. At the same time, the fault location method of overhead distribution network is analyzed when the DG access capacity is too large and the power supply distance is too long, and the feasibility and limitation of the switch setting adjustment strategy are analyzed by simulation. Aiming at the limitation of the traditional fault location method when the DG access capacity is too large and the power supply distance is too long, an improved matrix algorithm with DG is proposed. The algorithm automatically modifies the network description matrix according to the normal power flow direction of the distribution network under the normal power flow direction, and acquires the first order fault judgment matrix quickly only according to the first order fault information matrix uploaded by FTU. According to the characteristics of power network structure and Kirchhoff's law, the fault criterion of T-node region is improved, and the fault location method under the condition of incomplete or distorted FTU uploading information is proposed. The location accuracy of single fault and multiple fault in each region of feeder is improved, thus solving the problem that the traditional matrix algorithm needs to assume multiple positive directions of fault location according to the number of power supply. Some problems such as low accuracy rate of fault location in T-node region with large amount of calculation in fault determination and normalization are discussed. The accuracy and fault tolerance of the improved matrix algorithm are verified by an example. Due to the distortion caused by the external environment, weather and other factors, the fault tolerance of the improved matrix algorithm is greatly reduced when the number of FTU aberrations is large, so the fault tolerance of the improved matrix algorithm is greatly reduced when the distribution network is located in the actual fault location, which is due to the influence of the external environment, weather and other factors. Genetic algorithm is introduced for fault location of distribution network with DG. In view of the problem that the traditional genetic algorithm can not adapt to the different switching conditions of DG after DG is connected to the distribution network, the accuracy and stability of fault location are reduced. In this paper, an improved genetic algorithm is proposed to adapt to the changeable distribution network structure. The algorithm improves the crossover and mutation operators to speed up the convergence of the algorithm and avoid falling into local optimization. By improving the switching function and fitness function, the algorithm can better adapt to DG switching and improve the stability and efficiency of fault location. To solve the problem of calculating speed of fault location in large-scale distribution network, the idea of hierarchical processing is introduced to accelerate the speed of fault location. The simulation results show that the improved genetic algorithm is effective in the case of single fault and multiple faults in the distribution network system with DG. At the same time, the distortion and loss of FTU uploading information are analyzed. The stability, accuracy and fault tolerance of the improved genetic algorithm, the traditional genetic algorithm and the improved matrix algorithm in different fault cases are compared. The example shows that the improved genetic algorithm has better stability and fault tolerance.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM711

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