分布式电源对配电网电压暂降的影响

发布时间：2018-11-28 11:59

【摘要】：人类社会发展的脚步愈来愈快,对地球上各类自然能源如煤、石油等的消耗日益增多。那么发掘新的可供人们使用的资源,并且将其运用到发电系统中是现代社会的当务之急。分布式电源(DG)种类众多,在配电网中普遍应用的是利用风能的风力发电和利用太阳能的光伏发电。在集中发电和大电网运行的基础上,现代电力系统正逐步向含有分布式电源的新型电网发展。然而,随着DG对配电网渗透率不断提高,电网的电压质量不可避免的受到影响,需要引起人们的重视。本文根据DG的发电特点叙述其并网后给系统电压质量带来影响的机理,之后对DG的三种并网方式和两种常用的分布式电源进行建模,并网方式主要有同步发电机并网,异步发电机并网和逆变器并网。风力发电模型主要由风速和风力机两大块组成,太阳能发电模型主要包括并网数学模型和逆变器控制方法。对DG并网理论分析后,本文对含分布式电源的配电网电压质量问题,以及分布式供电系统电压—功率特性展开讨论。对于电压暂降问题,文章列举了三类常用的电压暂降随机预估方法,并对比后选择蒙特卡罗模拟法。该方法需要建立故障特征的随机模型,其作用是用来产生随机的故障信息,从而对实际电力系统进行有效模拟。文章采取仿真的形式来研究配电网的电压暂降问题以及DG接入配电网是如何造成影响的。按照蒙特卡罗法在PSCAD软件中搭建模型,以一个27节点的中压配电网为测试对象,并考虑DG在不同类型、容量、接入位置和控制方式的情况下并网以及故障特征的随机模型,采取电压暂降评估指标即系统平均方均根值变化频率进行评估。仿真结果表明通过合理调整DG在以上四个方面的配置能够降低电压暂降的发生频次,这为DG在配电网中的配置优化和缓解配电网电压暂降提供理论依据。
[Abstract]:With the rapid development of human society, the consumption of all kinds of natural energy such as coal and oil on the earth is increasing day by day. Therefore, it is an urgent task for modern society to discover new resources that can be used by people and apply them to power generation systems. There are many kinds of distributed power generation (DG), which is widely used in distribution network by wind power generation and solar photovoltaic power generation. On the basis of centralized generation and operation of large power grid, modern power system is gradually developing to a new type of grid with distributed generation. However, with the increasing permeability of DG to the distribution network, the voltage quality of the power network is inevitably affected, which needs to be paid more attention to. According to the characteristics of DG power generation, this paper describes the mechanism of its influence on the voltage quality of the system after being connected to the grid, and then models the three grid-connected modes of DG and the two commonly used distributed power sources. The main grid-connected modes are synchronous generator and grid-connected. Asynchronous generator grid-connected and inverter grid-connected. Wind power model consists of wind speed and wind turbine. Solar power model mainly includes grid-connected mathematical model and inverter control method. After the theoretical analysis of DG grid connection, this paper discusses the voltage quality problem of distribution network with distributed generation, and the voltage-power characteristics of distributed power supply system. For voltage sag, this paper enumerates three kinds of stochastic estimation methods of voltage sag, and then selects Monte Carlo simulation method. This method needs to establish a stochastic model of fault characteristics, which is used to generate random fault information, so as to effectively simulate the actual power system. In this paper, the voltage sag of distribution network and how the DG is connected to the distribution network are studied in the form of simulation. According to Monte Carlo method in PSCAD software, taking a 27 bus medium voltage distribution network as the test object, and considering the random model of DG network connection and fault characteristics under different types, capacity, access location and control mode. The evaluation index of voltage sag, that is, the change frequency of the average square root value of the system, is adopted to evaluate the voltage sag. The simulation results show that the frequency of voltage sag can be reduced by adjusting the configuration of DG in the above four aspects, which provides a theoretical basis for the configuration optimization of DG in distribution network and the mitigation of voltage sag in distribution network.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM714.2

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