含高比例分布式光伏的主配网紧急切负荷策略研究

Research on the Emergency Load Shedding Strategy for Transmission and Distribution Networks with High Penetration of Distributed Photovoltaic

随着新型电力系统接入高比例分布式光伏和不同等级的重要负荷,传统紧急切负荷策略对于日益紧密的互联电网适应性较差,导致分布式光伏或重要负荷脱网,随即引起更严重的连锁故障。提出了一种含高比例分布式光伏的主配网紧急切负荷策略。分析提取主配电网极端运行参数,通过风险评估构建紧急场景集;在主网层提出基于事件和响应的双驱动切负荷策略,通过主网切负荷优化模型求取紧急场景各配网切负荷量,并存入离线数据库用于事件驱动模块,基于离线数据库构建的随机森林模型用于响应驱动模块;在配网层通过分析各馈线重要度,以切负荷后果严重度最小为目标构建配电网最优切负荷模型,将可中断负荷参与减载作为切负荷的第一轮次,求取切负荷量和切负荷地点;在含高比例分布式光伏的105节点系统中进行仿真分析,与另2种切负荷策略对比,验证了所提策略能够使电网风险有效下降的同时降低分布式光伏和重要负荷脱网对系统的影响。

With integration of high proportions of distributed photovoltaic and different levels of important loads into new power systems,the traditional emergency load shedding strategies have poor adaptability to increasingly tight interconnected power grids,leading to the disconnection of distributed photovoltaic or important loads,and subsequently causing more serious chain failures.This paper presents an emergency load shedding strategy for transmission and distribution networks with high-scale distributed photovoltaic.First,the extreme operating parameters of transmission and distribution networks are extracted and emergency scenarios set is constructed through risk assessment.Second,an event-based and response-based dual-drive load shedding strategy is proposed in the transmission network layer.The load shedding optimization model of the transmission network is established to calculate the load shedding amount of the distribution network in emergency scenarios,which is stored in the offline database for the event-driven module,and the random forest model based on the offline database is used for the response-driven module.Furthermore,at the distribution network layer,by analyzing the importance of each feeder,the optimal load shedding model is constructed with minimizing the severity of load shedding consequences as the goal.The interruptible load is taken as the first round of load shedding to find the optimal load shedding quantity and location.Finally,the simulation analysis of a 105-node system with high-scale distributed PV is carried out,comparing with the other two load shedding strategies,the results show that the proposed strategy can effectively reduce the risk of power network and reduce the impact of both distributed PV and important load offline on the system.