分布式电源对配电网继电保护的影响研究

发布时间：2018-03-01 18:53

本文关键词： 分布式电源继电保护短路电流准入容量配电网　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,分布式电源作为可靠、高效、经济的发电方式得到广泛的关注。分布式电源和电网结合被电力、能源专家们认为是节能降损、节省投资、提高电力系统的灵活性和可靠性的主要方式。分布式电源的研究和应用给电力系统带来了活力,也带来了挑战。传统的配电网大多为单电源、辐射状结构,保护的整定也是基于此设计的。配电网中接入分布式电源后使网络结构、电网潮流以及短路电流发生变化,从而影响保护的正常运行。首先,对配电网的三段式电流保护的原理和整定,自动重合闸与保护的配合进行介绍。对分布式电源的定义、分类、特点以及并网方式进行研究,建立了分布式的电源并网的仿真模型。分析分布式电源不同接入点和接入容量对继电保护与重合闸的影响,配电网由单电源变为多电源系统,短路电流的分布和大小发生变化,从而引起保护以及重合闸的拒动或误动。电网发生故障时,还有可能形成非计划孤岛。其次,分析接入分布式电源短路电流的计算方法,从保护协调性的角度出发,采取串联电抗器和限制准入容量来消除分布式电源与保护协调性的问题。短路时,利用电抗的高阻抗特性限制分布式电源所提供的短路电流。建立分布式电源的准入容量模型,以线路故障时不影响保护正常动作为约束,研究单个和多个分布式电源最大准入容量及其对保护的影响,算例验证上述方法的有效性。最后,针对配电网现有的保护方案,通过修改整定值、装设方向元件和采取差动保护等对原方案加以改进。
[Abstract]:In recent years, distributed power generation, as a reliable, efficient and economical way of generating electricity, has received wide attention. The combination of distributed generation and power grid is considered by energy experts as energy saving and investment saving. The main way to improve the flexibility and reliability of power system. The research and application of distributed generation bring vitality and challenge to power system. The setting of protection is also based on this design. The network structure, power flow and short-circuit current are changed after the distribution network is connected to the distributed generation, which affects the normal operation of the protection. First of all, the principle and setting of three-section current protection in distribution network, the cooperation of automatic reclosing and protection are introduced. The definition, classification, characteristics and grid-connected mode of distributed power generation are studied. The simulation model of distributed power supply connection is established. The influence of different access points and access capacity of distributed power source on relay protection and reclosing is analyzed. The distribution network changes from a single source to a multi-source system, and the distribution and size of short-circuit current change. This will cause protection and reclosure failure or misoperation. Unplanned islands may also be formed when the power network fails. Secondly, the calculation method of short-circuit current in distributed power supply is analyzed. From the point of view of protection coordination, series reactor and limited access capacity are adopted to eliminate the problem of coordination between distributed power supply and protection. By using the high impedance characteristic of reactance to limit the short circuit current provided by distributed power supply, the admission capacity model of distributed power supply is established, which is constrained by the fact that the line failure does not affect the normal operation of the protection. The maximum access capacity of single and multiple distributed power sources and its effect on protection are studied. The effectiveness of the proposed method is verified by an example. Finally, according to the existing protection scheme of distribution network, the original scheme is improved by modifying the setting value, installing directional elements and adopting differential protection.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM77

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