应用于配电网柔性互联的变换器拓扑

Exploration on Power Converter Topologies Applied in Flexible Interconnection of Distribution System

大量分布式能源的接入,以及用户负荷的多样化,将使配电网双向潮流、电压越限、馈线负荷不均衡等问题更加突出。利用电力电子技术实现配电网的柔性互联,可在不增加配电系统短路电流的条件下灵活控制潮流,是推动配电网形态结构与运行模式升级的有效方案。该文对应用于配电网柔性互联的变换器拓扑进行了探究。依据接入方式、工作原理、基本结构的差异,将多种柔性互联拓扑进行多层级分类;在充分考虑配电线路特性的基础上,建立了接入各类变换器的配电网等效电路和相量图,深入研究其潮流调节机理,并归纳相应典型拓扑的结构特点与运行方式;对比分析不同配电网柔性互联拓扑的功能性与经济性,给出了多种类型拓扑的适用场景。通过以上工作,为不同配电网应用场景下柔性互联拓扑的选取提供了参考,并指明拓扑在未来的改进方向,以期推动柔性互联方案在装备实现层面的技术进步。

The integration of distributed generation and the diversity of user’s load, lead to reverse power flow, voltage rise and feeder imbalance, which will deteriorate the operation of distribution system. Flexible interconnection that takes advantage of power converters between distribution feeders could be a feasible solution, which could control the power flow without increasing short-circuit current. In this paper, the power converter topologies applied in flexible interconnection of distribution system was explored from the perspective of power electronics. The topologies were classified based on the integration type, operation principle and basic structure. The equivalent circuits and phasor diagrams of distribution grid integrated with different power converters were established. The power flow control mechanism of different topologies was studied based on the consideration of the features of distribution feeders. The characteristics of typical topologies were concluded. The functionality and economy of topologies were compared. At last, the suitable application settings of different topologies were analyzed. Researchers can figure out the topology requirements and choose the suitable topology for the specific application environment. Furthermore, the way to improve converter topologies will be indicated, so as to promote the technological development in flexible interconnection scheme.