柔性互联微网模式紧急切换平滑控制策略

Smooth Control Strategy for Emergency Switching of Interconnected Microgrids via FMS

微电网与柔性多状态开关构成的柔性互联多微网是构建以分布式电源为主的新型配电网的主要途径之一。为解决互联微网紧急状态下模式切换产生的冲击,提出微网和柔性多状态开关协调控制的平滑切换策略。分析功率调节、过渡状态、紧急控制3个阶段的特点,提出微网储能自适应下垂系数控制方法,解决切换时延过程源荷失衡造成的电压与频率稳定问题,提出协同相角补偿-协同控制切换-预同步的柔性多状态开关平滑切换方法,平抑切换瞬间柔性多状态开关初始相角和控制方式突变造成的冲击。利用PSCAD/EMTDC建立柔性互联微网仿真模型,验证所提策略可有效抑制微网模式紧急切换冲击,实现微网的持续安全稳定运行。

The flexible interconnected multi-microgrids composed of microgrids and flexible multi-state switches(FMS) are one of the main ways to construct active distribution network with high proportion of distributed generation(DG).To solve the mode switching impact of flexible interconnected microgrids in the emergency state, a smooth switching strategy for the coordinated control of the microgrids and the flexible multi-state switch was proposed. The characteristics of the three stages of the power regulation, transition state, and emergency control were analyzed, and an adaptive control method of the droop coefficient of the energy storage system(ESS) was proposed to solve the voltage and frequency stability problems caused by the imbalance of the source and load during the switching time delay. A smooth switching method of collaborative phase angle compensation,collaborative control switching and pre-synchronization was proposed to smooth out the instantaneous impact of switching caused by the sudden change of the initial phase angle and control mode of FMS. A simulation model of flexible interconnected microgrids was established through PSCAD/EMTDC, and the proposed strategy was verified to effectively suppress the impact of emergency switching of microgrid mode and thus realizing the continuous safe and stable operation of the microgrids.