含虚拟同步机的微电网频率稳定约束优化调度研究

Virtual Synchronous Machines (VSM) improve the grid integration compatibility of distributed energy resources. Therefore, there is a wide prospect for deployment of VSM in microgrids. However, traditional optimal dispatch methods are difficult to ensure a microgrid with sufficient inertial and frequency stability adequacy to withstand a major disturbance. . To fully take advantage of VSM's virtual inertial and frequency control characteristics, so as to enhance a microgrid’s resilience to withstand major frequency disturbances and also lower the operating cost, this proposed program will focus on the “Microgrid Frequency Stability Constrained Optimal Dispatch (FSCOD) With Virtual Synchronous Machines” . First, analyzing the impact mechanism of frequency stability of a microgrid enabled with mixed VSM, building analytical models of inertia, reserve and frequency stability constraints. Then, studying the corresponding FSCOD models for a microgrid operated in connected or isolated modes, proposing a reformulation approach with bound tightening and dynamic segmentation techniques to efficiently solve the models. Lastly, taking the frequency support benefits of customer owned VSM into account, building an FSCOD model with multiple decision-makers, and exploring the fast Analytical Target Cascading algorithm embedded with objective approximation and proximity operator. Results of this proposal would provide fundamental theoretical support for the optimal energy management of VSM dominated microgrids.

虚拟同步机(VSM)可有效改善分布式能源并网兼容性，在微电网中具有广阔的应用前景。传统优化调度方法难以确保微电网在扰动事件下具有足够的惯性和频率稳定裕度。为了充分利用VSM的虚拟惯量和有功调频特性，增强微电网的频率抗扰能力和运行经济性，本项目紧扣“含虚拟同步机的微电网频率稳定约束优化调度”开展研究：剖析混杂VSM交互作用对微电网频率稳定的影响机理，构建计及VSM的微电网转动惯量、旋转备用与频率稳定约束解析模型；建立不同运行模式下耦合混杂VSM运行特性的微电网频率稳定约束优化调度模型(FSCOD)，提出基于边界紧缩和多元动态分割的高效变形重构求解技术；建立激励用户私有VSM参与调频的微电网多主体FSCOD决策模型，引入目标逼近和近邻算子实现快速目标级联求解。项目预期成果可为虚拟同步机接入下的微电网能量优化管理提供基础理论支持。

含高密度分布式新能源的微电网在有功扰动事件下(如并网运行时联络线突然中断、孤岛运行时机组停运或负荷剧烈波动)易出现频率失稳。多类型虚拟同步机(VSM)的混杂并网可增加微电网运行控制的灵活性，但不同资源的功率协调控制与能量管理是含VSM的微电网需解决的关键问题。为了充分利用VSM的虚拟惯量和有功调频特性，本项目紧扣“含虚拟同步机的微电网频率稳定约束优化调度”开展研究：构建了耦合混杂VSM（光伏VSM、风机VSM、储能VSM）虚拟惯量及有功调频特性的微电网频率响应模型，量化VSM个体及聚类对微电网惯量与备用支撑的贡献度，提出了计及混杂VSM的微电网转动惯量计算方法和旋转备用容量修正计算策略；基于多层极限学习机、堆栈降噪自动编码器等数据驱动方法建立关键特征与频率变化率、暂态极值频率偏差、准稳态频率偏差等指标的非线性映射关系，实现频率稳定的在线智能化评估；给出了微电网最低惯量需求的定义，综合考虑影响微电网惯量需求的关键因素，构建了适用于并网和孤岛运行模式的微电网最低惯量需求评估模型；建立耦合VSM虚拟惯量与备用支撑的微电网频率稳定约束的解析表达式，分别考虑计划/非计划脱网事件和内部功率扰动事件，建立与并网和孤岛模式频率响应能力相适应的微电网频率稳定约束优化调度(FSCOD)模型，实现含VSM多主体FSCOD问题的优化决策。本研究可有效评价多类型VSM参与下的微电网惯量与备用需求，在满足事故暂态频率指标限制情况下对各运行时间点混杂VSM的功率基准值与荷电状态、传统机组启停状态和出力、多类型发电资源备用容量及其分布情况进行协调优化。项目成果可为VSM接入下的微电网能量优化管理提供基础理论支持，对于增强微电网频率抗扰能力、提高VSM利用率和促进分布式可再生能源友好接纳具有重要意义。