基于网源荷柔性多端互联直流配电中心的城市配电网运行控制技术研究

For an intelligent distribution network, it is vital to transform the static operation structure to the intelligent structure of flexible and active operation by improving the observability and controllability of the power distribution system. Although the wide application of DFACTS technology has greatly increased the controllability of distribution network, the control model used to be the way of single component and single parameter, and the controllability still cannot be increased by comprehensive multi-controls..This project proposes a topological structure of closed loop operation of city distribution network based on flexible multi-terminal DC distribution center with connected with DGs and loads, which can accommodate the flexible connections of DG, energy storage, electric vehicle, and strengthen the operation of city distribution network for a long run..Its main research contents include:.1) The topology of the flexible multi terminal DC interconnected distribution center based on grid, generations and loads, and the coordinated controls of multi converters. Then the optimal management of energy integration on different time scale has been realized for distribution network, DG, energy storage and charging facility of electric vehicle. .2) Economic operation of city distribution network based on flexible multi terminal DC distribution center connected with grid, generations and loads, including optimal power flow control, optimal operation of distribution network and voltage / reactive power control..3）Optimize configuration technology of flexible interconnection power electronics switch of city distribution network, in which several feeders , DG and loads are interconnected with the flexible multi terminal DC distribution center.

提高配电系统的能观性和能控性，把配电网从静态运行结构转变为灵活的、可主动运行的“智能”结构，是实现智能配电网的关键。DFACTS技术的广泛应用极大提高了配电网的可控能力，但仍停留于单元件、单一控制方面，难以从多个方面同时提高配电网的可控能力。本项目提出一种基于网源荷柔性多端互联直流配电中心的城市配电网闭环运行拓扑结构，以适应分布式电源、储能设备、电动汽车充电设施的柔性接入，提高城市配电网的运行水平。其主要研究内容包括：.1）网源荷柔性多端互联直流配电中心拓扑结构及多电能变换器间协调控制策略，用以实现配电网、分布式电源、储能设备、电动汽车充电设施多时间尺度能量融合优化管理；.2）基于网源荷柔性多端直流配电中心的城市配电网经济运行控制技术研究，包括最优潮流控制、配电网优化运行、电压/无功控制。.3）基于网源荷柔性多端直流配电中心配电网中的柔性互联电力电子开关优化配置技术研究。

（1）背景. 现有配电网采用以供方主导、单向辐射供电为主的运行模式，未形成馈线间实时功率互济、高渗透率分布式电源和大容量冲击性负载网级承载的闭环供电模式，是制约能源结构调整、供给侧改革及绿色发展的技术瓶颈。在上述因素的推动下，配电网将从静态结构转变为灵活的、主动的“智能”结构，形成分布式可再生能源和微电网为重点的多元电力供应、“网源荷储充”深度融合的新形态。.（2）研究内容. 为了解决多能流接入传统交流配电网后的多端直接耦合造成的系统复杂性急剧上升，稳定性下降的关键技术难题，本项目组提出了一种基于直流配电中心的网源荷储充柔性互联的新型配电体系，攻克了协调控制、优化运行、优化调度、优化配置等方面的关键技术，并将其应用于实际工程中，实现了风、光、储、充及网的多能流解耦和能源综合利用，建设了国际首个五端柔性互联交直流配电网示范工程，引领了配电网未来形态演变进程。.（3）重要结果和关键数据：. 1）提出了一种基于DDC的柔性互联架构及供电体系，实现了“网源荷储充”在物理结构上互联互济；. 2）提出了基于多馈线均衡的分布式电源、集中式储能、大容量充电站的面消纳技术，有效提升了配电网的运行控制水平和间歇式源荷的承载水平。. 3）提出了基于直流配电中心的不停电转供技术，并在实际工程实现了非计划不停电转供，奠定了高可靠供电的理论和应用技术基础。