考虑多元源荷深度互动的交直流混合配电网谐波耦合特性与传播规律研究

交直流混合配电网可有效结合交流供电与直流供电的优势，是我国智能配电网未来较长时间的主导供电形态。在大规模分布式新能源和多元负荷深度互动场景下，交直流混合配电网中的谐波呈现出新特征。一是谐波源种类大幅增加、谐波具有更强的分散性、随机性和时变性，二是多谐波源之间的耦合程度进一步增强。针对多电压等级交直流混合配电网中谐波扰动的产生、传播和溯源等关键问题，本项目通过分析典型多元源荷的谐波扰动发射机理与谐波动态特性，研究多个谐波源之间的相互耦合影响并阐明谐波扰动与电压波动的相互关系；以交直流变换器与直流变压器为关键节点，研究交直流混合配电网中不同频率谐波的传播规律与耦合机理；探究交直流混合配电网中的谐波源辨识与责任划分方法，建立配电网谐波扰动的分级预警机制。本项目将全面分析交直流混合配电网中谐波的动态特征、传播规律及责任评估，为多元源荷深度互动场景下有效控制交直流混合配电网的谐波水平提供决策依据。

Since the hybrid AC/DC distribution network has both the advantages of AC and DC supply system, it will be the dominate power supply form in the future smart distribution network for a long period in China. With the high penetration of distributed renewable resources and multiple flexible loads, the harmonics in the hybrid AC/DC distribution system have some new features. Firstly, the types of the harmonic sources increase greatly, and the harmonics generated in the system are widely distributed. Harmonics in the distribution system are random and time varying. Secondly, the harmonic coupling degree between the multiple harmonic sources is more serious than ever before. Aiming at the harmonic generation, propagation and identification in the multi-voltage level hybrid AC/DC distribution network, the dynamic harmonic generation mechanism and characteristics of the typical harmonic sources will be firstly studied. Then the coupling relationship among the multiple harmonic sources will be analyzed, and the interaction between the harmonics and voltage fluctuation will be studied. After that, the harmonic propagation mechanism and coupling degree under different harmonic frequencies will be researched by analyzing the key system components of AC/DC converters and DC/DC transformers. Finally, in hybrid AC/DC distribution network, the harmonic source identification and harmonic contribution division will be explored, and a hierarchical harmonic pre-warning mechanism will be proposed. This project will comprehensively analyze the mechanism of harmonic generation, propagation and evaluation of the harmonic sources in the hybrid AC/DC distribution network. The results will provide basis for the comprehensive management and control strategies of the harmonic pollution in systems with high penetration of renewable resources and flexible loads.