基于DDC的直流微电网接入技术研究

以直流配电中心(DC Distribution Center,DDC)为核心构建的柔性互联配电网能够实现多回馈线闭环运行,对提升配网可靠性运行水平和对新能源的消纳能力具有重要意义。文中基于DDC重点研究了以DAB为核心的直流微网接入技术。首先分析了DAB的基本结构和工作原理,并设计了相应的控制策略；然后对含有光伏、直流负载的简单直流微网及相关模型进行介绍；最后利用PSCAD/MTDC搭建了四端交直流柔性互联配电系统,验证通过DAB实现直流微网与DDC互联的技术可行性。结果证明直流配电中心系统能够稳定运行,直流变压器能够满足直流微网接入的技术需求；在稳态及受到扰动时,系统能够维持稳定运行,直流负荷供电不受影响。

Research on DC Microgrid Access Technology Based on DDC

The flexible interconnected distribution network with DC distribution center (DDC) as the core can realize closed-loop operation of multiple feedback lines, which is of great significance for improving the reliability operation level of distribution network and the ability to absorb new energy. Based on DDC, this paper focuses on the DC micro-network access technology with DAB as the core. Firstly, the basic structure and working principle of DAB are analyzed, and the corresponding control strategies are designed. Then, the simple DC micro-grid and related models with photovoltaic and DC loads are introduced. Finally, the four-terminal AC-DC flexible interconnection is built by using PSCAD/MTDC. The power distribution system verifies the technical feasibility of interconnecting the DC microgrid with the DDC through DAB. The result proves that the DC power distribution center system can operate stably, and the DC transformer can realize the technical requirements of DC microgrid access. When the steady state and the disturbance are disturbed, the system can maintain stable operation and the load power supply is not affected.