基于电力电子变压器的配电网无功优化关键技术研究

发布时间：2018-07-05 17:50

  本文选题：电力电子变压器 + 配电网　； 参考：《沈阳农业大学》2017年硕士论文

【摘要】：无论是过去的配电网还是如今的智能配电网,电压都是衡量系统稳定性与否的非常重要的元素,也就是说对配电网进行无功优化是十分重要的。就国内的配电网而言,大多数都是处于无功不足的网络,所以其网损非常恶劣,这样大大消耗了国家的财力和物力。现今的配电网越来越复杂,对其的无功优化所选取的方法不能再居于传统的一系列形式。传统无功优化的几种方法已经很难应对现今的复杂系统,面对复杂问题很容易就收敛到局部最优解更有甚者有不收敛的可能性。本文主要以寻找新的算法来针对配电网的无功优化问题进行相应改进,从而更有效的解决如新复杂的配电网优化问题。降低网损对整个电网而言有着非常重要的意义,不仅是节省财力和物力,更对社会人文生活提供了更加优越的环境。配电网的主要构成有:线路、变压器、电容器、负荷等。由这些器件所构成的网络称为配电网络,其中变压器在输配电环节又是重中之重。对于现今的配电网而言,想要做到无功合理分配基本有这几种方式:运用调相机调节(发出和吸收无功,但基本淘汰)、有载调压变压器的分接头调压、小电容器大规模成组投切系统中、静止无功补偿装置等等。本文主要针对于有载调压变压器的分接头调压这种无功优化手段进行改进分析,主要通过将有载调压变压器(OLTC)替换为新型的电力电子变压器(EPT),总结电力电子变压器的优缺点,从而分析替代的可行性。分析配电网首要就是潮流计算,不改变系统运行的前提下通过潮流计算可对各个节点的电压情况、各个支路分布功率的情况以及网络功率损耗的情况。对于配电网的无功优化问题,提出新的改进后的遗传算法,其应对现今复杂配电网的能力尤为突出,并予以实例分析证明其可行性。针对配电网无功优化问题改进的遗传算法全局搜索能力强,速度迅捷,可更为有效的搜寻到最优解。将改进的遗传算法应用于配电网的无功优化中,在配电系统中用EPT代替OLTC后,对某市的实际电网算例进行无功优化,并且对比了含有传统有载调压变压器的配电网的优化和含有电力电子变压器的配电网的优化。系统受到小扰动时对简化的两节点系统做仿真实验,通过分析仿真结果证明电力电子变压器可提高系统稳定性。
[Abstract]:Whether in the past or today, voltage is a very important element to measure the stability of the distribution network, that is to say, reactive power optimization is very important. As far as the domestic distribution network is concerned, most of them are in the network with insufficient reactive power, so the network loss is very bad, which consumes the national financial and material resources greatly. Nowadays, the distribution network is becoming more and more complex, and the method of reactive power optimization can no longer live in a series of traditional forms. Several traditional reactive power optimization methods have been difficult to cope with the current complex systems. In the face of complex problems, it is easy to converge to the local optimal solution and even have the possibility of non-convergence. In this paper, a new algorithm is found to improve the reactive power optimization problem of distribution network, so as to solve the new complex distribution network optimization problem more effectively. Reducing network loss is of great significance to the whole power network, not only to save financial and material resources, but also to provide a better environment for social and human life. The main components of the distribution network are: lines, transformers, capacitors, loads and so on. The network composed of these devices is called distribution network, in which transformers are the most important in transmission and distribution. For today's distribution network, there are several ways to achieve rational distribution of reactive power: adjusting (emitting and absorbing reactive power, but basically eliminating) by using a camera, adjusting voltage by tap of on-load voltage regulating transformer, In the large-scale group switching system of small capacitors, static var compensator and so on. This paper mainly focuses on the improvement and analysis of tap regulator of on-load voltage regulating transformer, and summarizes the advantages and disadvantages of power electronic transformer by replacing OLTC with a new type of power electronic transformer (EPT). Thus, the feasibility of substitution is analyzed. The power flow calculation is the most important part of the distribution network. Without changing the operation of the system, the voltage of each node, the distribution power of each branch and the power loss of the network can be calculated by power flow calculation. For the reactive power optimization problem of distribution network, a new improved genetic algorithm is proposed, which is especially capable of dealing with complex distribution network, and its feasibility is proved by an example. The improved genetic algorithm (GA) for reactive power optimization problem of distribution network has strong global search ability and fast speed, and can search the optimal solution more effectively. The improved genetic algorithm is applied to the reactive power optimization of the distribution network. After replacing OLTC with EPT in the distribution system, the reactive power optimization is carried out for the actual power network in a certain city. The optimization of the distribution network with the traditional on-load voltage regulating transformer and the distribution network with the power electronic transformer are compared. The simplified two-node system is simulated when the system is subjected to small disturbance. The simulation results show that power electronic transformer can improve the stability of the system.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM714.3
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本文编号：2101157