Autonomous control of distributed storages in microgrids

Operation of distributed generators in microgrids has widely been discussed, but would not be fully autonomous, if distributed storages are not considered. Storages in general are important, since they provide energy buffering to load changes, energy leveling to source variations and ride-through enhancement to the overall microgrids. Recognizing their importance, this paper presents a scheme for sharing power among multiple distributed storages, in coordination with the distributed sources and loads. The scheme prompts the storages to autonomously sense for system conditions, requesting for maximum charging energy only when excess generation capacity is available. As generation capacity drops or demand increases, energy drawn by the storages decreases spontaneously, until full source capacity is near. At which point, the storages release their stored energy for meeting the extra load demand. The described process takes place in an automated manner with energy sharing always maintained among the storages. To verify the concepts discussed, simulation was performed with its results shown near to the end of the paper.