极端天气下多阶段主动配电网弹性评估与提升方法研究

Extreme weather events threaten the security and stability of distribution system operation in China. The development of active distribution system (ADS) provides new means to enhance the resilience of the distribution system against the extreme weather events. This proposal will deeply study the multi-stage resilience evaluation and enhancement of the ADS against the extreme weather events. Firstly, based on the extreme weather information, its spatial-temporal evolution trend will be analyzed, and then a spatial-temporal mathematic distribution line failure model for the ADS will be established. Next, the resilience evaluation index system against extreme weather events for ADS will be constructed to evaluate the effects of the resilience enhancement strategies in pre-disaster stage and the post-disaster stage. In the pre-disaster defense stage, an optimal line hardening and distributed generator siting model for ADS resilience enhancement will be built providing line hardening and distributed generator layout strategy, and the rapid solution method will be studied. In the post-disaster restoration stage, the ADS optimal operation model considering the resilience enhancement will be established and the optimal strategy of the post-disaster load restoration and system island operation will be given. It is expected that this proposal will provide new methods and ideas for the ADS to enhance its resilience against extreme weather events in China and realize the scientific decision-making of multi-stage resilience enhancement of the ADS against the extreme weather events.

极端天气的侵袭严重威胁到我国配电网安全稳定运行，而主动配电网技术的发展为增强配电网抗极端天气弹性提供了新手段。本项目将深入研究极端天气下多阶段主动配电网弹性评估与提升方法。首先，依据极端天气气象信息，分析其时空演变趋势，建立主动配电网线路故障时空特性数学解析模型；其次，构建考虑极端天气影响的主动配电网弹性指标体系，提出一种适用于极端天气情形的主动配电网弹性评估方法，用于评估灾前和灾后两阶段不同弹性提升策略的优劣；在灾前防御阶段，构建考虑主动配电网弹性提升的线路加固与电源布置决策模型，并研究其高效求解技术，给出灾前线路加固和分布式电源布置最优方案；在灾后恢复阶段，建立考虑主动配电网弹性提升的负荷恢复与孤岛运行决策模型，研究模型近似等效方法并求解，给出灾后负荷恢复和孤岛运行最优方案。期望本项目能为我国主动配电网提供抵御极端天气的新方法和新思路，实现极端天气下多阶段主动配电网弹性提升的科学决策。

本项目针对极端天气严重威胁到配电网安全稳定运行这一问题，构建了极端天气下多阶段主动配电网的弹性评估与提升方法。 .项目研究内容及主要成果如下：.(1) 基于极端天气气象信息的配电线路故障时空特性建模方法。提出台风由侵入配电网至离开配电网区域全过程中移动风场参数的仿真近似模型，将主动配电网区域的地理环境网格化，计算多调度时段内的台风中心坐标、台风10级风圈范围、台风风场移动速度参数；基于划分的坐标系建立不同时段内风场中不同位置的风速大小与风向；基于风场内最大风速概率分布，计算考虑杆塔倾倒与线路刮断的配电网线路台风期间全时段综合故障率矩阵。.(2) 考虑极端天气影响的主动配电网弹性指标体系与评估方法。对于极端自然灾害，构建相应的线路故障率模型，基于蒙特卡洛抽样方法生成若干组故障场景；围绕弹性三大核心特征，应变力、防御力和恢复力，构建交直流混合配电网弹性评价指标体系；基于熵权法求得各指标的客观权重，并得到交直流混合配电网弹性综合评价结果。.(3) 灾前考虑主动配电网弹性提升的线路加固与电源配置决策建模及其求解方法。提出一种基于两阶段分布鲁棒模型的主动配电网线路-杆塔加固优化方案，模型在第一阶段确定线路加固与杆塔改造策略，第二阶段则基于台风期间配最差故障断线概率分布确定配网中分布式发电调度运行方案；以所有概率场景下主动配电网经济损失和配置均摊成本的期望值最低为目标函数，提出了主动配电网光伏与储能的节点与容量优化配置方案。.(4) 灾后考虑主动配电网弹性提升的负荷恢复与孤岛运行决策模型及其求解方法。考虑到极端台风灾害发生后配电网线路断线并解列成多个孤岛运行，针对如何高效实现配电网网络重构、分布式电源调度以促进灾后负荷恢复的问题，将灾后配电网弹性提升策略转化为多阶段马尔可夫决策过程，以联络线开关的投切指令为控制变量，以最大化负荷恢复为优化目标，并采用近端策略优化算法进行求解。