【作者】 荣延泽；

【导师】 刘士荣；

【作者基本信息】 杭州电子科技大学 ， 控制理论与控制工程， 2012， 硕士

【摘要】 随着传统单向传输大电网的弊端越来越明显，以及全球性的能源与环境问题越来越凸显，人们开始考虑把分布式能源作为大电网的重要补充。分布式发电不仅具有环保、效率高、安装地因地制宜等优点，而且可节省长距离输电线路的投资成本和损耗，保障在大电网发生意外停电时，能够提供基本的能源供应。因此，很多国家都已经开始考虑在配电网的用户区建设分布式电源。然而，分布式发电的随机性、小容量、小惯性、低过载能力等缺点，以及分布式发电接入对大电网的影响等诸多因素都制约着分布式发电技术的推广和实用。于是，微电网技术的出现就是为了解决这些难题。本文以Matlab/Simulink为仿真环境，以实证性研究项目中的微电网系统为平台，围绕分布式电源和微电网的相关技术为研究目标，重点阐述和研究了分布式电源建模、分布式电源接口控制技术以及微电网控制策略和保护。首先，根据各个分布式电源的数学原理或工程模型，建立了光伏电池、微型燃气轮机、蓄电池、超级电容器等几种分布式电源的模型。通过这些模型，仿真获得了它们相关的输出特性。实验结果表明，建立的模型较好的反应了这些分布式电源的特性，可以用于将来的研究。其次，考虑到分布式电源与馈线连接都要处理好接口问题，阐述了分布式电源接口与传统的同步发电机接口的区别。接着分别对逆变接口技术中的锁相环技术、脉宽调制技术、逆变器原理及其功率控制等展开分析和仿真。最后仿真实现了三相逆变器的PQ功率控制。然后，讨论了分布式电源的PQ控制、Droop控制和V/f控制三种逆变器接口控制技术，接着，介绍了当前微电网的主要控制策略。设计了Droop控制器，利用这种控制器做了与大电网连接的仿真实验，验证了所设计控制器的正确性。并作了微电网的主动孤网和孤网运行时负荷投切情况下的仿真实验，证明在负荷波动情况下，采用合适的控制策略能满足微网内电能质量要求。然后阐述了基于PID控制的并网点潮流控制的思路和设计方法，最后仿真验证了该控制策略下的并网点的功率控制情况，证实了该策略是正确和有效的。最后，分析了分布式电源接入后对传统继电保护的挑战和影响，在此基础上，阐述了微电网在并网和孤网运行时的继电保护对策，结合实证性微网系统中的继电保护实例，阐述了微网系统的保护层次、保护逻辑以及孤岛保护等情况。更多还原

【Abstract】 Distributed Generator (DG) becomes an important supplement for power grid, when thedisadvantages of the traditional one-way power grid is more and more obvious, and the globalenergy and environment problem is more and more pressing. The Distributed Generation iseco-friendly, high efficiency and has advantage in installation location of localization. Moreover, itcan reduce the transmission and distribution line loss, lower the operation cost, guarantee basicenergy supply when the power grid power has malfunction. However, there also somedisadvantages for the distributed power generation, such as randomness, small capacity, smallinertia, low overload ability, the influence of Distributed Generation access to power grid and so on.Many factors restrict the application and promotion of distributed power generation technology.Microgrid technique is developed to solve the above problems. In this study, the simulationenvironment is Matlab/Simulink, demonstrative research project of the grid-connection Microgridsystem works as a platform. Take the relevant technology of Distributed Generator and Microgridas application background, the modeling of Distributed Generator, inverter technology ofDistributed Generator and the control strategy and protection of Microgrid is discussed.Firstly, establish the model of Photovoltaic cells, Micro-turbines, Batteries and ElectricalDouble-Layer Capacitors according to their mathematical principles or engineering models. Withthese models, we study their relevant output performance by simulations. The experimental resultsshow that these models could reflect the characteristics of above Distributed Generators, and havesignificance to future research.Secondly, considering the problem of Distributed Generator interface to feeder connections,the difference between Distributed Generator and the traditional synchronous generator is discussed.Afterward, the interface technology of inverter, including phase lock loop technique (PLL), pulsewidth modulation (PWM) technology, inverter principle and power control are simulated andanalyzed. Finally, the three-phase inverter PQ power control is realized in the simulation.And then, three-phase inverter control technologies, including PQ power control, V/f controland Droop control are discussed. The mainstream control strategy of Microgrid is introduced. TheDroop controller is designed, with which the power grid-connection simulation experiments areimplemented. These simulation results demonstrate the validity of the designed controller. Then, theMicrogrid active isolated from grid and in the state of island operation inputting or cutting loadsimulated, in which, the results demonstrate that the grid power quality requirements can besatisfied by appropriate control strategy, even there is load wave. And then, the PCC’constant power control methods based on PID control are detailed. The control strategy of PCC’constantpower is tested by simulation, which proved the validity of this strategy.At last, the influence to the relay protection when Distributed Generator is applied to thetraditional power grid is discussed. Based on the above discussion, this thesis expounds theMicrogrid relay protection approaches in the state of connection and isolated to grid. According tothe protection of the empirical Microgrid system, the Microgrid platform’s protective hierarchy,protective logic and protection in the state of island are discussed.更多还原