Outline of Grid-interconnection Technologies of Distributed Generation Systems

Grid interconnections of distributed generation systems (DG) to the existing power grid are expected to increase in future due to concerns for environmental preservation and effective energy use. In this paper, targets and status of DG introduction are explained first. Then, outline of some projects intended to promote large-scale introduction of DG is described. It is required to consider the technical requirements for grid interconnection of DG to cooperate with existing power grid. History of DG grid interconnection rules is mentioned and recent progress of standards for DG interconnection testing is explained.