【作者】 张良；

【导师】 王树东； 庞晓东；

【作者基本信息】 兰州理工大学 ， 电气工程（专业学位）， 2021， 硕士

【摘要】 随着近年来光伏发电、风力发电等分布式发电规模日益扩大,越来越多的分布式电源接入电力系统,给以火力发电为主的传统电力系统带来新的特点和挑战,并给研究人员提出了大量的研究课题。分布式电源的接入势必会对电网安全以及用户用电可靠性造成影响。本文对分布式电源接入配电网后带来的电压影响进行研究,并建立相应的配电网风险评估体系,研究改进风险评估方法并使用算例验证改进后的方法的有效性和优越性。首先,对分布式电源的发电原理进行阐述,建立了光伏发电和风力发电的输出功率模型,并建立负荷的有功功率和无功功率的随机分布概率模型,为下文的计算做好铺垫。其次,就分布式电源的接入对配电网节点电压的影响进行详细研究。分析了单个分布式电源接入时,不同容量和不同位置对配电网电压影响的规律。前人对多个分布式电源同时接入的情况研究较少,于是分析了多个分布式电源同时接入的情况。阐述了不同的接入数量、容量和位置与各区间电压变化趋势的关系,进而总结出多分布式电源同时接入下对配电网电压影响的规律。为了改善这种影响,研究了接入以电动汽车为代表的典型可控负荷的解决方案,并采用IEEE33节点配电系统为算例对以上规律进行验证,比较了不同的电动汽车接入方案,得出了最佳解决方案。然后,对目前常用的配电网风险评估方法进行比较。比较了解析法和蒙特卡洛模拟法的各自特点,针对蒙特卡洛模拟法建模较为复杂、要求变量服从一定的概率分布、需要反复迭代、计算量较大等特点,对蒙特卡洛模拟法的两个重要使用技巧—等分散抽样法和重要抽样法进行结合,形成了改进的蒙特卡洛模拟法。改进后的方法很大程度上克服了原来这两种方法缺点并兼具它们的优点。最后,基于分布式电源对配电网电压的影响,建立了配电网风险评估体系,并运用改进后的蒙特卡洛法、重要抽样法和等分散抽样法对IEEE33节点配电系统进行风险评估,对比三种方法的计算结果,验证了改进方法的有效性和优越性。更多还原

【Abstract】 With the increasing scale of distributed power generation such as photovoltaic power generation and wind power generation in recent years,more and more distributed power sources are connected to the power system,bringing new characteristics and challenges to the traditional power system dominated by thermal power Researchers put forward a large number of research topics.The access of distributed power sources will inevitably affect the security of the power grid and the reliability of users’ electricity.This thesis studies the voltage impact caused by distributed power sources connected to the distribution network,and establishes a corresponding distribution network risk assessment system,studies and improves the risk assessment method,and uses examples to verify the effectiveness and superiority of the improved method.Firstly,the principle of power generation of distributed power is explained,the output power model of photovoltaic power generation and wind power generation is established,and the random distribution probability model of active power and reactive power of the load is established to pave the way for the following calculations.Secondly,a detailed study is made on the influence of the access of distributed power sources on the node voltage of the distribution network.When a single distributed power source is connected,the law of the influence of different capacities and different locations on the voltage of the distribution network is analyzed.Predecessors have rarely studied the simultaneous connection of multiple distributed power sources,so they analyzed the simultaneous connection of multiple distributed power sources.The relationship between the number,capacity and location of different connections and the changing trend of the voltage in each section is described,and then the law of the influence of multiple distributed power sources on the voltage of the distribution network is summarized.In order to improve this influence,the solution to connect to typical controllable loads represented by electric vehicles is studied,and the IEEE33-node power distribution system is used as an example to verify the above rules,and different electric vehicle access schemes are compared.Came up with the best solution.Then,compare the currently commonly used risk assessment methods for distribution networks.Comparing the respective characteristics of the analytical method and Monte Carlo simulation method,the Monte Carlo simulation method is more complicated in modeling,requires variables to obey a certain probability distribution,requires repeated iterations,and has a large amount of calculation.The combination of two important use techniques of Equal Dispersion Sampling and Importance Sampling has formed an improved Monte Carlo simulation method.The improved method largely overcomes the shortcomings of the original two methods and has their advantages.Finally,based on the influence of distributed power sources on the voltage of the distribution network,a risk assessment system for the distribution network was established,and the improved Monte Carlo method,importance sampling method,and other decentralized sampling methods were used to conduct risk assessment on the IEEE33 node distribution system.,Comparing the calculation results of the three methods to verify the effectiveness and superiority of the improved method.更多还原