考虑暂态约束的配电网关键负荷恢复优化决策与风险限制方法研究

Major outages caused by extreme events, such as natural disasters, cascading failures, and cyber attacks, pose negative effects on the economy, society, and security of power and energy systems. This project aims at resilience enhancement for distribution systems with distributed generators (DGs). The research is focused on the theory and methodology for utilization of local sources for service restoration to critical loads. Critical loads are connected to local sources, forming electrical islands that can operate independently. When using local sources for service restoration, the effects of transient characteristics of DGs on the feasibility of restoration strategies should be considered. The risk induced by intermittent energy resources should also be taken into account. To deal with those challenges, this project will conduct research in two aspects. Firstly, the algebraic model of transient constraints will be developed, and the optimization model and algorithm considering the transient characteristics of DGs will be proposed. Secondary, the modeling method and self-learning mechanism of the probability distribution density of power generated by intermittent energy resources will be studied, and a risk-limiting operation adjustment method for electrical islands will be proposed. The research in this project can provide theoretic and technical support for the enhancement of distribution system resilience.

自然灾害、连锁故障、网络攻击等极端事件导致的长时间、大面积停电事故对经济、社会及电力能源安全造成了诸多不利影响。本项目针对含分布式电源的中低压配电网，以韧性提升为目标，研究极端停电事故场景下利用本地电源快速恢复关键负荷的理论与方法。拟连接本地电源与关键负荷，形成独立运行的配电网孤岛，通过多电源协调配合实现在故障时段中对关键负荷的持续供电。利用本地电源恢复关键负荷时，应考虑分布式电源暂态特性对恢复策略可行性的影响，以及间歇性能源出力随机性带来的运行风险。为此，本项目从两个方面展开研究：（1）研究恢复策略暂态可行性约束的代数化建模方法，提出计及分布式电源暂态特性的配电网关键负荷恢复优化建模与求解方法；（2）研究极端灾害后间歇性能源出力时空联合概率分布统一建模方法与自学习机制，提出限制风险的配电网孤岛运行方式动态调整方法。项目研究成果可为配电网韧性提升提供理论依托与技术支持。

我国电网呈现高比例可再生能源和电力电子装备接入、负荷多元化、信息-物理高度融合等特点，电网特性更加复杂。与此同时，电网面临自然灾害、恶意攻击、连锁故障等内外部安全威胁。本项目针对非常规事件导致的大面积、长时间停电事故，提出利用分布式电源和储能快速恢复配电网重要负荷的理论与方法，在以下三个方面取得了重要进展：（1）提出了基于整数变量松弛迭代的故障恢复优化模型高效求解算法，给出并证明了获得最优解的条件，且从算法原理层面保证了收敛性和收敛速度。针对中国典型配电网62节点算例，所提算法的平均计算效率相比于采用通用优化求解器直接求解MISCOP模型提升了21倍，且在约70%的场景下获得了最优解。（2）建立了逆变器接口的分布式电源的频率响应模型，构建了代数形式的暂态频率约束，实现了考虑暂态频率约束的故障恢复问题快速决策。在IEEE13节点算例上，对比加入频率约束后的恢复策略，通过实际仿真验证所提出频率约束的有效性。（3）建立了间歇性电源出力概率分布自学习机制，准确描述不确定性；提出了故障恢复策略动态调整方法，降低了配电孤岛功率失衡和能量不足的风险。针对144节点算例，自学习机制显著提升了间歇性电源出力预测置信水平，故障恢复方案动态调整策略使得累积加权负荷供电时间提升了49.8%。