含柔性软开关的有源配电网故障恢复策略

Service Restoration Strategy of Active Distribution Network with Soft Open Points

随着智能配电网的发展,新型的电力电子装置柔性软开关(SOP)替代配电网中传统的联络开关(TC),可增加配电网运行控制的灵活性。分析了含SOP的有源配电网正常运行和故障情况下的SOP控制模式。对于配电网中部分失电区域由于严重故障致使无法通过联络开关连接到端电源的情况,文中将该失电区域称为失联侧子网,将其余可以通过联络开关与上级网络相连的区域称为联网侧子网,并据此提出了由SOP和分布式电源协同供电的故障恢复策略。该策略考虑了联网侧子网的转供能力,可为失联侧子网恢复运行提供相应的约束。通过设定SOP为Vf控制模式,以总失电负荷加权值最小、脱离主网分布式电源最少,以及网络损耗最小为目标函数,建立了含SOP的配电网故障恢复模型,优化变量为联络开关状态及SOP的出口电压,采用混沌蚁群联合优化算法进行求解。采用含SOP的单回IEEE 33节点系统、手拉手双回IEEE 33节点系统作为测试算例,从恢复策略和负荷波动适应性两个层面验证了所提故障恢复策略的有效性,仿真结果表明该恢复策略不仅能实现配电网失联侧最大恢复供电,还能保证配电网联网侧的正常运行。

With the development of smart distribution networks, the soft open point （SOP）, as a sort of promising electronic device in place of traditional tie switch （TC）, can improve the operating flexibility of a distribution network. This paper analyzes the SOP control modes of an active distribution network with SOPs under normal and fault conditions. For the special case that an arising serious fault prevents some regions from the contact with the grid through switches, each of the referred regions is called an unconnected subnetwork, the rest regions that can contact with the grid are called connected subnetworks. Then a service restoration strategy to restore the black-out loads by cooperating SOPs with distributed generators （DGs） is proposed. The power-transferring capability of the connected subnetwork is taken into account, which can provide the corresponding constraints for the restoration of the unconnected subnetwork. The SOP operates in a Vf mode during the service restoration. The objective function consists of the minimum weighted total loss of power load, the least DGs out of the grid and the minimum network loss. A service restoration model for the distribution network with SOPs is developed. The optimization variables are the output voltages of tie switch and SOP. Moreover, the ant colony optimization and chaos algorithm are combined to realize the restoration strategy. Finally, the case studies are conducted on a single IEEE 33-bus system with an SOP and a double IEEE 33-bus system, which show the effectiveness of the proposed service restoration strategy in both recovery schemes and load fluctuation adaptability. The simulation results show that the restoration strategy can not only realize the maximum restoration of the unconnected subnetwork, but also ensure the normal operation of the connected subnetwork.