基于CSC和MMC的混合直流配电网技术研究

Research on hybrid DC distribution network based on CSC and MMC

交流配电网存在线路损耗大,供电走廊紧张,易受到分布式电源冲击,电能质量不稳定等问题。将来配电网极有可能形成传统交流配电网和直流配电网共存互联的情况。文章针对直流配电网与交流配电网连接的拓扑结构分类讨论,分析了不同场景下的直流配电网的拓扑选择。提出了一种适用于分布式电源接入的基于CSC和MMC的混合换流器拓扑结构,并研究了相应的控制策略,既发挥了CSC占用面积小,又解决了CSC产生谐波的固有缺陷。在PSCAD/EMTDC平台上搭建仿真模型。结果表明,这种混合换流器可以实现对交流侧谐波的有效抑制,稳定交流电压,增强了交直流配电网的可靠性。

There are many problems in AC distribution network, such as high line loss, tension in power supply corridor, easy to be impacted by distributed power supply, unstable power quality and so on. In the future, the distribution network is likely to form the coexistence and interconnection of the traditional AC distribution network and the DC distribution network. In this paper, the topological structure of DC distribution network and AC distribution network is classified and discussed, and the topology selection of DC distribution network in different scenes is analyzed. A hybrid converter topology based on CSC and MMC is proposed for distributed generation access, and the corresponding control strategy is studied. It not only exerts the small occupied area of the CSC, but also solves the inherent defect of the harmonic generation by CSC. The simulation model is built on the PSCAD/EMTDC platform. The results show that the hybrid converter can effectively suppress the harmonics of the AC side, stabilize the AC voltage, and enhance the reliability of AC and DC distribution network.