Use of demand response for voltage regulation in power distribution systems with flexible resources

In low‐voltage power distribution systems with high penetration of photovoltaics (PVs) generation and electric vehicles (EVs), the over‐voltage problem arises at times because of large PV generation, and under‐voltage problem also arises sometimes because of simultaneous charging of massive EVs. Over‐ and under‐voltage problems lead to more difficulties in achieving voltage regulation. Demand response (DR) is expected to be promising and cost‐effective in promoting smart grids, and hence, the utilisation of flexible resources (FRs) through DR can be helpful for distribution system voltage regulation. This study introduces a hierarchical control structure of a community energy management system (CEMS) and multiple sub‐CEMSs to apply an FR‐based two‐stage voltage regulation technique. In the first stage, i.e. the day‐ahead scheduling stage, each sub‐CEMS optimises the FRs’ schedules for minimising customers’ electricity cost and network voltage violation times. In the second stage, i.e. the real‐time operation stage, the voltage sensitivity‐based FRs’ shifting method is proposed to eliminate network voltage violations caused by errors of estimated day‐ahead data. The proposed models and methods are verified based on a realistic distribution system in Japan, where voltage violations, customer electricity cost and a number of on‐load tap changer tap operations are proved to be reduced.