基于柔性多状态开关互联的配电网平滑转供策略

Smooth Transfer Strategy for Distribution Networks Based on Flexible Multi-State Switch Interconnection

配电网主要以“闭环设计、开环运行”为主,一旦上级馈线发生故障,就极易造成分布式电源脱网和负载停电,影响配电网安全稳定运行。针对传统基于交流联络开关的配电网转供方式难以避免短时停电和转供冲击的问题,提出一种基于柔性多状态开关(Flexible Multi-State Switch,FMSS)互联的配电网平滑转供策略,建立FMSS互联配电网转供模型,设计ESS协同FMSS的配电网平滑转供控制策略,FMSS由并网模式的恒功率控制切换至离网模式的恒频恒压控制,ESS采用全过程下垂控制,平抑切换过程中的频率电压波动。在PSCAD/EMTDC建立基于柔性多状态开关互联的配电网模型,对比无ESS和无平滑手段的方式,验证所提策略平抑转供冲击的有效性。

The distribution network in China is mainly based on"closed-loop design and open-loop operation".Once there is a fault in the upstream feeder line,it is highly probable to cause disconnection of distributed generation and power supply interruption,which affects safe and stable operation of distribution network.The traditional distribution network transfer method based on AC interconnecting switches is difficult to avoid short-term power outages and transfer impacts.This paper proposes a smooth distribution network transfer strategy based on flexible multi-state switch(FMSS)interconnection.The FMSS interconnection distribution network transfer model is established,and smooth transfer control strategy with ESS coordinated FMSS is designed.FMSS switches from constant power control under grid-connected mode to constant frequency and constant voltage control under off-grid mode,and ESS adopts full-process droop control to alleviate frequency and voltage fluctuations during the switching process.A distribution network model based on flexible multi-state switch interconnection is established in PSCAD/EMTDC,and comparative analysis against method without EES and method without smoothing is performed,confirming the effectiveness of the proposed strategy in smoothing transfer impacts.