Applicability of demand response to voltage control in a distribution system with large integration of rooftop PV

The capacity of installed photovoltaic (PV) generation in Japan is the world´s 3^rd largest and has been increasing rapidly due to the governmental subsidy and feed-in tariff programs. The rapid increase in PV installations drives electric utilities to various problems on how to operate the electric power systems stably. Then the utilities have to invest heavily in the systems. Under the circumstances, we are researching the possibility of implementing a demand response (DR) program as an alternative measure to the conventional power supply investment against the voltage rise problem in distribution systems with PV. We may be able to realize more efficient investment by the new solution with DR. This paper shows new findings based on our simulations of voltage control by DR in distribution systems with high integration of PV. By the simulations based on the realistic input data, we clarified the economic efficiency and the applicability of DR.