兼容分布式电源的直流配电系统的分析研究

发布时间：2018-01-23 20:05

本文关键词： 直流配电网电压等级拓扑结构并网接口控制分布式电源　出处：《北京交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：传统交流配电网由于三相不平衡、电压波动和闪变、频率波动、谐波等电能质量问题以及无功功率造成的送电容量限制,已逐渐无法满足用电设备的需求。而直流配电网在提高运行效率、改善供电可靠性和电能质量、实现新能源有效安全接入等配电系统面临的关键问题上有显著优势。目前各国对直流配电网的研究都还处在试验探索阶段,对其深入研究还较少,但可以预见的是直流配电网凭借着强大的技术和经济优势将有着广阔的发展前景。首先,本文结合直流配电系统中的分布式电源,介绍直流配电网的发展历程及国内外研究现状,详细论述其技术特点和优势。其次,对直流配电网的系统构架,包括中低压系统的拓扑结构、标准电压及母线结构等进行全面的阐述。最后,通过对直流配电网的控制模式及其各单元模块的研究提出了双向AC/DC、DC/DC两级式并网接口,并采用相对独立的双闭环控制策略及单闭环DC/DC直流负载控制和双闭环DC/AC交流负载控制。本文基于智能电网研究院与内蒙古电力公司的合作项目,为某实验园区用户供配电网络提供了一种直流配电网方案。选定AC/DC容量为300kW,其中光伏容量共计50kW,交流负荷66kW和直流负荷94kW。为提高直流配电网的供电可靠性,本文选择4个容量相同的l00kW的变流器作为并网接口,其中三个用来正常运行,其余一个作为备用变流器。针对低压直流配电系统交流主网三相不平衡,直流负荷突然增加及光伏出力突然降低三种不同模式下的运行情况进行了仿真研究,结果表明两级式并网接口能很好的稳定直流母线电压且负载侧电压能维持在其额定值附近,整个系统也能维持功率平衡,验证了所提出控制策略的有效性及直流配电系统的可行性。
[Abstract]:Traditional AC distribution network due to three-phase imbalance, voltage fluctuations and flicker, frequency fluctuations, harmonics and other power quality problems, as well as reactive power caused by the capacity constraints. The DC distribution network has been unable to meet the demand of the electric equipment gradually, and the DC distribution network is improving the operation efficiency, the reliability of power supply and the power quality. At present, the research on DC distribution network in many countries is still in the stage of experiment and exploration, but the deep research on it is still less. However, it can be predicted that DC distribution network will have a broad development prospect by virtue of its strong technical and economic advantages. First of all, this paper introduces the development of DC distribution network and domestic and foreign research status, discusses its technical characteristics and advantages in detail. The system architecture of DC distribution network, including the topology of the medium and low voltage system, the standard voltage and the bus structure, etc. Through the research on the control mode of DC distribution network and each unit module, the bi-directional AC / DC / DC / DC two-stage grid-connected interface is proposed. And the relative independent double closed loop control strategy, single closed loop DC/DC DC load control and double closed loop DC/AC AC load control are adopted. Based on the cooperative project between the Smart Grid Research Institute and Inner Mongolia Electric Power Company, this paper provides a DC distribution network scheme for the users in a certain experimental park. The AC/DC capacity is selected as 300kW. The total capacity of PV is 50kW, AC load 66kW and DC load 94kW. in order to improve the reliability of DC distribution network. In this paper, four 10kW converters of the same capacity are selected as grid-connected interfaces, three of them are used for normal operation and the other one is used as backup converter, aiming at the three-phase imbalance of AC main network in low-voltage DC distribution system. The simulation of three different modes of DC load sudden increase and photovoltaic force sudden reduction is carried out. The results show that the two-stage grid-connected interface can stabilize the DC bus voltage and maintain the load side voltage near its rated value, and the whole system can maintain power balance. The effectiveness of the proposed control strategy and the feasibility of DC distribution system are verified.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM721.1

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