高比例新能源微电网群多尺度宽频域动态特性分析及分布式模型预测镇定控制研究

When microgrid interconnections form microgrid clusters, stability issues can escalate rapidly. Microgrid clusters with high proportion of renewable energy are prone to coupling between source and source, between source and load, and between sub-microgrid and sub-microgrid. Subsystems with wide time-scale characteristics will significantly change the dynamic behavior of the system over a wider frequency band, thus, new stability or oscillation issues are created. In this project, a multi-scale dynamic modeling method for microgrid clusters with high proportion of renewable energy is proposed, giving consideration to both multi-scale features and computational speed. From the perspective of multi-time, multi-space and wide-frequency-band scales, the new oscillation phenomenon in the microgrid clusters is discovered, and the generation mechanism and evolution law of multi-scale oscillations are revealed, and the stability quantification results are obtained. A hierarchical distributed model predictive stabilization control strategy considering scale decoupling, and strong robustness for complex and variable operating conditions and information failure is proposed to achieve effective stabilization of multi-scale oscillations of microgrid clusters. On this basis, the hardware-in-the-loop simulation experiments based on RT-LAB are completed. The research results have important scientific significance for exploring the multi-scale dynamic characteristics and suppression methods of microgrid clusters under the background of high proportion of renewable energy and high proportion of power electronics and summarizing the basic physical laws. At the same time, it will provide key theoretical basis and technical support for the safe and stable operation of microgrid clusters with high proportion of renewable energy in practical projects.

当微电网互连形成微电网群时，稳定性问题可能会迅速升级。高比例新能源微电网群内极易产生源源、源荷、子微电网之间的耦合，各种宽时间尺度特性的子系统在更宽频带范围内交互将显著改变系统的动态行为，产生新的稳定或振荡问题。本项目提出兼顾刻画多尺度特征与计算速度的高比例新能源微电网群降阶多尺度动态建模方法；从多时间、多空间和宽频带尺度视角探索发现微电网群存在的新型振荡现象，揭示多尺度振荡的产生机理和演化规律，获取其稳定性量化结果；提出尺度解耦、对复杂多变运行工况及信息失效具备强鲁棒性的分层分布式模型预测镇定控制策略，实现微电网群多尺度振荡的高效镇定；完成基于RT-LAB的硬件在环仿真实验验证。研究成果对探索认识高比例新能源与高比例电力电子背景下微电网群多尺度动态特性问题与抑制方法，归纳其中基础性物理规律具有重要的科学意义。同时，将为工程中实现高比例新能源微电网群安全稳定运行提供关键理论基础及技术支撑。

地理位置邻近的微电网由于互联互供所需形成微电网群系统。微电网群内部能量互补机制可有效缓解源荷时空差异性对单个微电网运行控制产生的压力，增强系统运行的可靠性，进一步提升可再生能源消纳水平。本项目针对微电网群低碳安全稳定运行面临的技术挑战，系统开展建模、动态特性分析及控制基础理论与关键技术研究。首先，提出了弱电网条件下双馈及直驱风电机组主动响应系统调频的自适应动态下垂控制策略，构建了新能源发电电压源参与系统调频的技术体系，进一步地，建立了高比例新能源微电网群的动态模型，基于快慢动态耦合交互的非经典奇异摄动特性，研究了两种混合动态辨识方法并提出了兼顾刻画多尺度特征与计算速度的微电网群降阶多尺度动态模型建立方法。其次，基于群系统动态模型特征根分析和多时间尺度交互分析，首次发现了微电网群内由于多时间尺度交互作用形成的混合局部/区域间振荡模式，并进一步揭示了微电网群的振荡动态行为和弱阻尼振荡机理，量化分析了系统稳定性，获取了不确定新能源发电出力下关键状态量的可达集。最后，提出了考虑直流环节动态、具备快速动态响应以及振荡抑制能力的新能源发电有限控制集模型预测控制方法，基于最优部分输出反馈控制机理设计形成了分层分布式阻尼控制策略，实现了在低通信负担下微电网群的优化控制，进一步地，基于几何测度能观可控量化分析结果设计了上下层镇定控制器控制地址及反馈信号并形成分层分布式模型预测镇定控制策略，实现了对微电网群多尺度振荡的高效抑制。本项目的研究工作探索认识了高比例新能源与高比例电力电子背景下新型电力系统运行控制机理，相关研究成果可为实现微电网群安全稳定运行以及提升可再生能源消纳能力提供关键理论基础及技术支撑。