摘要
In recent years, against a background of an environmental problem and resource problem, the introduction of RES (renewable energy source) such as wind power generation and PV (photovoltaic generation), EV (electric vehicle), and PHEV (Plug-in hybrid electric vehicle) has been expanding. However, various problems have an ongoing discussion. When the production of electricity by RESs exceeds the power consumption, it is possible to cause a steep variation of point voltage and a deviation from a proper voltage range in a distribution system to which RESs are interconnected. When EVs and PHEVs have spread to the distribution system, a new peak power-demand and a steep voltage drop might occur in the midnight charging time zone in case the electricity charges are low. in this paper, the authors analyze the effects on the distribution system under widespread PVs, EVs, and PHEVs. In addition, the authors propose an improvement plan and analyze about the influence and contribution.