直流配电网电能质量扰动及污染源定位研究

With the advantages of power availability, controllability, efficiency, reliability and adaptation for integrating renewable energy, DC distribution system is a development tendency for future distribution systems. The DC power quality problem is a core issue for the planning, designing and operation control of DC distribution systems. However, it appears new features due to the fluctuation of source and load, the diversity of disturbance and the sensibility of power conversion equipment. Aiming at the key problems including the generation of power quality disturbances in DC distribution network, its propagation in multi-level distribution network and the localization of pollution source, the research will study the generation mechanism of DC power quality pollutions under the continuous emitting and short-term disturbing situations to analyze the coupling relationship between different DC power quality phenomena. Afterward, according to the investigations of the voltage transforming characteristic and the ride-through operating limit of DC transformer suffering the different forms of power quality disturbance, in combination of the emission models of source and load of DC power quality pollutions, the propagation law of power quality disturbance components with different frequencies will be revealed in multi-level DC distribution networks. Based on the system propagation model of DC power quality and the selection of state variables, the dynamic state estimation method of power quality in multi-level DC distribution networks will be proposed to trace the pollution sources. Furthermore, to deal with the information uncertainties of dynamic localization, the fusion localization strategy of power quality pollution source can be designed by using the combination of the static section location and the dynamic source tracking. As an intended outcome of this research, the theoretical supports can be provided for the system construction of DC power quality, the design and operation specification of DC transformer and the operation, maintenance and management of DC distribution network.

直流配电网以供电能力强、可控性好、高效可靠和适应可再生能源接入等优势，已成为未来配电系统的发展方向。直流电能质量是其规划、设计、运行和控制的核心问题之一，但源荷波动性、扰动多样性和功率变换设备敏感性使它呈现新的特点。针对直流配电网电能质量扰动的产生、多级配电网间传递、污染源定位等关键问题，本项目研究持续发射和短时扰动下直流电能质量污染产生机理，据此分析不同直流电能质量现象间的耦合关系；从扰动激励下直流变压器的电压转换特性及不脱网运行极限入手，结合直流电能质量污染的源荷发射模型，探索不同频率分量下多级配电网中的电能质量传递规律。在系统传递模型及状态量选取的基础上，提出多级直流配电网电能质量动态估计方法，再考虑动态定位可能出现的信息不确定性，设计静态区段定位和动态溯源相结合的污染源融合定位策略。本项目的实施为直流电能质量体系构建、直流变压器设计运行规范和直流配电网运维管控提供理论支持。

直流电能质量分析是直流配电网可靠运行的基础。本项目针对直流配电网电能质量扰动的产生机理、传递计算、污染源定位等需求，建立直流电能质量污染持续发射及短时扰动模型，提出其对配电设备影响的严重度评估方法；揭示了不同直流电能质量现象间的耦合关系，构建了直流配电网电能质量质量指标体系。分析直流电能质量污染传播过程，构建以直流变压器为枢纽的直流电网仿真模型，分析正常和极限条件下直流变压器电压转换关系，建立多级直流配电网电能质量指标传递模型；提出直流变压器传递模型的参数估计方法，建立多级直流配电网电能质量动态估计模型及算法；将直流电能质量污染的区段定位和动态估计相结合，提出直流电能质量污染源的静动态融合定位策略；研究了不同电力电子设备对直流配电网电能质量指标的抑制特性，从“源-网-荷-储”不同角度出发，提出了直流配电网极间不平衡电压、电压偏差、电压波动、谐波等的污染治理方法。搭建了具有多种典型拓扑结构模拟功能的直流配电网实验平台，验证模型及方法的可行性和实用性。本项目的顺利实施为智能配电网的电能质量控制和管理功能提供理论和技术支撑，为我国建设坚强智能电网以及保障电网稳定运行、用户可靠供电提供重要的工程应用价值。