含微网的配电系统继电保护研究

发布时间：2018-04-02 11:10

本文选题：微网　切入点：分布式发电　出处：《华中科技大学》2014年硕士论文

【摘要】：现如今，环境问题和能源问题越来越凸显，开发清洁可再生能源资源已经成为各国经济及社会可持续发展的重要战略。微网可以降低馈线损耗、增加本地供电可靠性、提高能源利用的效率，越来越受到各国的重视。但是微网由于接入了多个储能装置和分布式发电，使配电系统的故障特征发生改变，故障后电气量的变化变得非常复杂，影响了传统的保护原理和故障检测方法，可能导致故障位置无法准确定位。因此对配电网的保护进行重新配置是微网大量应用的关键。微网由分布式电源、负荷、储能装置和控制装置构成，它有两种运行模式，即并网运行和离网运行。本文首先分析了微网的控制模式及微网在并网和离网两种运行模式下DG逆变器的控制模式，并网运行时，微网内的各个DG逆变器的控制一般采用P/Q控制方式。离网运行时，微网内部需要某个或者某几个DG采用U/f和Droop控制策略来保持电压和频率的额定值。据此建立微网并网运行时逆变型DG的等效模型，在分析常规配电网结构和继电保护配置的基础上在PSCAD/EMTDC中建立了含微网的配电系统的仿真模型。然后在分析DG故障特性的基础上，详细分析了微网对常规配电网继电保护的影响，包括引起保护误动、拒动，灵敏性降低以及对重合闸的影响等。最后提出了一种基于通信的继电保护配置方案，并考虑了重合闸装置，利用在PSCAD/EMTDC中建立的仿真模型，验证了继电保护新方案的有效性。
[Abstract]:Nowadays, environmental and energy problems are becoming more and more prominent, and the development of clean and renewable energy resources has become an important strategy for the sustainable development of economy and society.Microgrid can reduce the loss of feeder, increase the reliability of local power supply and improve the efficiency of energy utilization.However, due to the access of multiple energy storage devices and distributed generation, the fault characteristics of the distribution system are changed, and the change of electrical quantity becomes very complicated after the fault, which affects the traditional protection principle and fault detection method.The fault location may be unable to locate accurately.Therefore, reconfiguration of distribution network protection is the key to a large number of microgrid applications.The microgrid is composed of distributed power source, load, energy storage device and control device. It has two operation modes, that is, grid-connected operation and off-grid operation.In this paper, we first analyze the control mode of microgrid and the control mode of DG inverter in grid-connected and off-grid mode. In grid-connected operation, the control mode of DG inverter in microgrid is generally P / Q control mode.In off-grid operation, one or more DGs are required to maintain the voltage and frequency ratings by using U- / f and Droop control strategies.On the basis of this, the equivalent model of the inverter DG is established. Based on the analysis of the conventional distribution network structure and relay protection configuration, the simulation model of the distribution system with microgrid is established in PSCAD/EMTDC.Then, based on the analysis of DG fault characteristics, the influence of microgrid on the relay protection of conventional distribution network is analyzed in detail, including the maloperation of protection, the rejection of protection, the reduction of sensitivity and the influence on reclosure.Finally, a relay protection configuration scheme based on communication is proposed, and the reclosing device is considered. The effectiveness of the new scheme is verified by using the simulation model established in PSCAD/EMTDC.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM77

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