SVG及其对电力系统电压稳定性影响的研究

发布时间：2018-12-13 22:33

【摘要】：随着工业的发展及社会的进步,用电负荷逐渐增加,大规模电力系统逐步形成,电能质量的要求也越来越高,而电压是电能质量的重要指标之一,电力系统的电压稳定性问题不仅仅是一个供电的问题,同时还是关系到大电网安全运行的重要问题,因此越来越多的学者开始投入到对系统电压稳定性这一问题的研究中。系统的电压水平是电力系统无功功率供需平衡情况的具体体现,在传输的过程中,无功功率的损耗会直接的影响到电压的降落,而为了保持电压的稳定,就要进行无功补偿。随着科技的发展,静止无功发生器(Static Var Generation,简称SVG)成为目前最先进的无功功率补偿装置,因此,深入研究SVG对电力系统电压稳定性的影响,具有重大的理论与现实意义。本文的研究内容主要包括以下几个方面:1.本文采用无功优化中的一种算法来确定电力系统的补偿容量,通过现阶段常用的几种无功优化算法的比较采用了小生境遗传混合算法,首先介绍了这种算法的数学模型与工作流程,然后用这种算法来对本文所选用的标准系统进行无功容量的确定,即为无功补偿装置的容量。2.在上述工作基础上,设计了一种级联多电平的SVG,主电路采用6个H桥级联的多电平逆变器的拓扑结构;控制策略上采用了三相电流的比例谐振PR(Proportion-Resonant,PR)控制,比例谐振控制器能够在静止坐标系下对工频电流进行无静差调节,无须dq旋转坐标变换,无须正负序分解,因此减少了电流检测中dq变换这一部分,使SVG的控制更为方便些,也节省了无功补偿动作的时间。3.通过无功优化对系统容量的确定以及本文所设计的SVG,将其投入到所选系统中来研究SVG对电压稳定性的影响,本文选择了两个标准系统来进行分析,分别是三机九节点系统与IEEE33节点系统。通过仿真分析了SVG对电压稳定性的影响,且得出并验证了SVG对系统的电压稳定性的提高及SVG在电力系统中的应用价值。
[Abstract]:With the development of industry and the progress of society, the electric load increases gradually, the large-scale power system is gradually formed, the requirement of power quality is higher and higher, and the voltage is one of the important indexes of power quality. The voltage stability of power system is not only a power supply problem, but also an important problem related to the safe operation of large power grid. Therefore, more and more scholars have begun to study the voltage stability of power system. The voltage level of the system is the concrete embodiment of the supply and demand balance of reactive power in power system. In the process of transmission, the loss of reactive power will directly affect the voltage drop, but in order to maintain the stability of the voltage, reactive power compensation should be carried out. With the development of science and technology, the static Var Generator (SVG) has become the most advanced reactive power compensation device. Therefore, it is of great theoretical and practical significance to study the influence of SVG on the voltage stability of power system. The research content of this paper mainly includes the following aspects: 1. In this paper, an algorithm of reactive power optimization is used to determine the compensation capacity of power system. This paper first introduces the mathematical model and workflow of the algorithm, and then uses this algorithm to determine the reactive power capacity of the standard system selected in this paper, that is, the capacity of the reactive power compensator. Based on the above work, a cascaded multilevel SVG, main circuit using 6 H-bridge cascaded multilevel inverters is designed. In the control strategy, the proportional resonance PR (Proportion-Resonant,PR) control of three-phase current is adopted. The proportional resonance controller can adjust the power frequency current without static error in the static coordinate system, without the dq rotation coordinate transformation and the positive and negative sequence decomposition. Therefore, the part of dq transform in current detection is reduced, the control of SVG is more convenient, and the time of reactive power compensation is also saved. Through the reactive power optimization to determine the system capacity and the SVG, designed in this paper into the selected system to study the impact of SVG on voltage stability, this paper selected two standard systems for analysis. It is a three-machine nine-bus system and a IEEE33 node system. The effect of SVG on voltage stability is analyzed by simulation, and the improvement of voltage stability of SVG system and the application value of SVG in power system are obtained and verified.
【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM712

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