微电网系统建模及其保护方案的研究

发布时间：2018-04-12 16:46

本文选题：微电网 + 微电源　；参考：《内蒙古科技大学》2014年硕士论文

【摘要】：微电网是一种新型的单一可控的配电网单元，它可以通过自身的控制策略有效的协调调度其内部的分布式微电源，最大程度的减少分布式微电源单独接入电网时所产生的弊端，从而保证分布式微电源大规模的高效利用。但是，由于微电网在不同运行模式下所表现出的故障特征有所不同，，这使得传统的依靠电流模值作为判断条件的三段式电流保护难以作为微电网保护方案，并有效满足配电网保护的四个标准即：选择性、可靠性、灵敏性、速动性。因此，微电网保护技术成为微电网取得进一步发展的关键，同时也成为微电网研究的热点问题。本文以PSCAD/EMTDC为仿真环境，以分布式微电源和微电网的建模、控制与保护为研究对象。首先，分析说明了分布式电源逆变器的数学模型以及拓扑结构，认真研究了分布式电源逆变器的P/Q控制以及基于下垂特性的V/f控制，并在PSCAD中建立了这两种分布式电源的仿真模型，仿真其输出特性，为进一步的研究打好基础。然后，完成了包含光伏发电装置，直驱式风力发电机组，蓄电池储能单元的低压微电网模型的分析与建立，并完成了如下仿真实验：改变环境因素观察微电源功率输出的改变对于微电网运行的影响，平滑转换孤岛运行与并网运行之间的运行状态以及离网状态下完成投切负荷等状况对微电网运行带来的影响，进而验证了微电网模型建立的合理性以及运行的稳定性。理论分析了微电网特殊的故障特征，并针对简单的微电网模型进行了仿真实验，验证了微电网在不同运行模式下，特殊的故障特征。最后，阐述了继电保护中的电流差动保护和反时限过电流保护的基本原理，并依靠仿真软件中的元件建立了二者的保护模块，以保护模块为基础，详细论述了微电网在联网和孤岛的不同运行状态下的馈线保护方案，并辅以仿真实验，佐证了所提出的保护模块和保护策略的合理性以及有效性。
[Abstract]:Microgrid is a new type of single controllable distribution network unit. It can effectively coordinate and dispatch its internal distributed micro-power through its own control strategy, and minimize the disadvantages of the distributed micro-power alone when it is connected to the grid.In order to ensure a large-scale and efficient use of distributed micro-power.However, due to the different fault characteristics of microgrid in different operation modes, it is difficult for the traditional three-section current protection which depends on the current mode value as the judgment condition to be used as the microgrid protection scheme.And meet the four standards of distribution network protection, namely, selectivity, reliability, sensitivity and quickness.Therefore, microgrid protection technology has become the key to the further development of microgrid, and has also become a hot issue in microgrid research.In this paper, PSCAD/EMTDC is taken as the simulation environment, and the modeling, control and protection of distributed micro-power and microgrid are taken as the research object.Firstly, the mathematical model and topology of distributed power inverter are analyzed, and the P / Q control and V / F control based on droop characteristic of distributed power source inverter are studied.The simulation models of these two distributed power sources are established in PSCAD, and the output characteristics are simulated, which lays a good foundation for further research.Then, the analysis and establishment of the low-voltage microgrid model including photovoltaic generation unit, direct-drive wind turbine and storage battery unit are completed.The following simulation experiments have been completed: changing the environmental factors to observe the influence of the power output of the micro-power supply on the operation of the microgrid.The special fault characteristics of microgrid are analyzed theoretically, and the simulation experiments on simple microgrid model are carried out to verify the special fault characteristics of microgrid in different operation modes.Finally, the basic principles of current differential protection and reverse time overcurrent protection in relay protection are expounded, and the protection modules are established based on the components in simulation software.The feeder protection scheme of microgrid in different operation states of interconnection and isolated islands is discussed in detail, and the simulation results show that the proposed protection module and protection strategy are reasonable and effective.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM727

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