适于微电网可控开关无缝切换的无源网络优化设计

含可再生能源的分布式发电系统在配电网和微电网中的渗透率正日益提高,供电可靠性得到提高。但配电网和微电网中大量敏感负荷对电压质量的要求日渐严格,要求外部电网故障时微电网工作状态能"无缝切换"。针对现有微电网与外部电网连接的可控开关方案在无缝切换过程中存在的问题,文中提出了一种适于微电网可控开关无缝切换的无源网络优化设计方案。在外部电网发生电压暂降时刻实现微电网向孤岛模式的无缝切换,确保敏感负荷的可靠运行,同时也有效实现微电网公共连接点电能质量问题的综合治理。通过数学建模和数值计算确定了无源网络的优化设计方法,建立了典型算例的PSCAD/EMTDC电磁暂态仿真验证了该方法的有效性。

Passive Network Optimization Design for Seamless Switching of Controllable Switches in Microgrid

The penetration of distributed generation system with renewable energy is increasing in the distribution networks and microgrids, which improves the reliability of power supply. However, a large number of sensitive loads accessing to the distribution networks and microgrids also have increasingly strict requirements on the voltage quality. Therefore, the seamless switching of microgrid working states is required when faults occur in the external grids. Aiming at the problems of the existing controllable switching scheme between microgrids and the external grids during the seamless switching procedure, this paper proposes a passive network optimization design method for the controllable switches in the microgrid. It can not only achieve seamless switching of microgrid to island mode when voltage sag occurs, to ensure the reliable operation of sensitive loads, but also provide an effective way to comprehensively solve the power quality problems at the point of common connection of microgrid. The design method of the passive network is determined by mathematical modeling and numerical calculation and validated by electromagnetic transient simulation of typical cases in PSCAD/EMTDC.