From flexible interconnection among feeders to hybrid alternating current(AC) and direct current(DC)distribution structures of future smart distribution systems medium-voltage DC distribution centers with flexibly int...From flexible interconnection among feeders to hybrid alternating current(AC) and direct current(DC)distribution structures of future smart distribution systems medium-voltage DC distribution centers with flexibly interlinked multiple microgrids(MGs) will have wide applications on the demand side. A generic coordinated control framework based on a distributed cooperation scheme is proposed for such DC centers, as opposed to centralized control structures. A novel unified control only using local measurements is proposed for these interlinking converters. During normal power disturbances, automatic coordinated power control and mutual support among sub-systems can be realized, thereby improving DC voltage and AC frequency stability to enable multiple MGs to be treated as a real unified cluster. Moreover, with this method, interlinking converters can realize seamless transition in power dispatching mode, common DC bus voltage control mode, and MG support mode without communication and control system switching. A simplified dynamic model has been developed to verify the proposed control strategy. This work is expected to provide a new solution for flexible interconnection and operational control of large-scale MG clusters.展开更多
城市配电网的多回交流馈线通常采用闭环接线、开环运行模式,不具备线路相互之间的可控功率支持。利用背靠背多端换流器将多回10 k V线路柔性互联,可以将传统配电网的开环运行模式转变为闭环运行模式。本文针对采用直流配电中心柔性互联...城市配电网的多回交流馈线通常采用闭环接线、开环运行模式,不具备线路相互之间的可控功率支持。利用背靠背多端换流器将多回10 k V线路柔性互联,可以将传统配电网的开环运行模式转变为闭环运行模式。本文针对采用直流配电中心柔性互联的多回10 k V线路,提出了一种基于负载均衡策略的直流功率实时调制技术,即利用馈线有功功率分配系数实现有功功率偏差控制,实现了多回线路之间的负载均衡。通过PSCAD/EMTDC仿真软件构建了一个含四端混合式子模块MMC的交直流柔性互联配电系统,并在主从控制的基础上,利用基于负载均衡策略的功率调制技术、改进了直流配电中心的控制策略。仿真结果表明,在减少系统负荷测量点的情况下,所提直流功率调制策略能跟随负荷的波动实时平衡馈线之间的负载,提高交流配电网的设备利用率及运行可靠性。展开更多
基金supported by National NaturalScience Foundation of China (No. 51507109, No. 51707128)Science and Technology Project of China Southern Power Grid (No. GZKJQQ00000417)
文摘From flexible interconnection among feeders to hybrid alternating current(AC) and direct current(DC)distribution structures of future smart distribution systems medium-voltage DC distribution centers with flexibly interlinked multiple microgrids(MGs) will have wide applications on the demand side. A generic coordinated control framework based on a distributed cooperation scheme is proposed for such DC centers, as opposed to centralized control structures. A novel unified control only using local measurements is proposed for these interlinking converters. During normal power disturbances, automatic coordinated power control and mutual support among sub-systems can be realized, thereby improving DC voltage and AC frequency stability to enable multiple MGs to be treated as a real unified cluster. Moreover, with this method, interlinking converters can realize seamless transition in power dispatching mode, common DC bus voltage control mode, and MG support mode without communication and control system switching. A simplified dynamic model has been developed to verify the proposed control strategy. This work is expected to provide a new solution for flexible interconnection and operational control of large-scale MG clusters.
文摘城市配电网的多回交流馈线通常采用闭环接线、开环运行模式,不具备线路相互之间的可控功率支持。利用背靠背多端换流器将多回10 k V线路柔性互联,可以将传统配电网的开环运行模式转变为闭环运行模式。本文针对采用直流配电中心柔性互联的多回10 k V线路,提出了一种基于负载均衡策略的直流功率实时调制技术,即利用馈线有功功率分配系数实现有功功率偏差控制,实现了多回线路之间的负载均衡。通过PSCAD/EMTDC仿真软件构建了一个含四端混合式子模块MMC的交直流柔性互联配电系统,并在主从控制的基础上,利用基于负载均衡策略的功率调制技术、改进了直流配电中心的控制策略。仿真结果表明,在减少系统负荷测量点的情况下,所提直流功率调制策略能跟随负荷的波动实时平衡馈线之间的负载,提高交流配电网的设备利用率及运行可靠性。
