Development of a resilient hybrid microgrid with integrated renewable power generations supplying DC and AC loads

Abstract

This paper presents an experimental study with a pilot hybrid microgrid system that is proposed and implemented in Tagajo campus of Tohoku Gakuin University, Japan. The developed microgrid system is designed to be able to supply power to both DC and AC loads simultaneously by renewable power sources such as PV and wind power generations, etc. Meanwhile, in case that the renewable power is insufficient to supply both these loads, a diesel generator is automatically actuated as backup power source. For the purpose of power balance and voltage stabilization, two types of energy storage devices with different response characteristics and cost, which are secondary battery and EDLC (Electrical Double-layer Capacitor) respectively, are introduced into this system. In this work, a coordinated control strategy for these energy storages were proposed and verified by a series of experimental studies with the developed hybrid microgrid system. The purpose of the experimental study addressed in this paper is to confirm the islanded operation properties of this system for stable power supply to both AC and DC loads, even in case with considerable power fluctuation of renewable sources and significant power change in loads. As a result of this study, it is illustrated that the developed hybrid microgrid and its control systems can work properly and resiliently as being designed.