Voltage Stabilization with Reactive Power Compensation from Demand Side Equipment

―Cost-effectiveness Analysis Method under Various Sorts of Installations―

Abstract

The installed capacity of photovoltaic (PV) systems has been increasing rapidly due to the enforcement of the feed-in tariff scheme in Japan. However, reverse power flows from the roof-mounted PV systems cause voltage-rises in distribution networks. As for the voltage stabilization with reactive power compensation, SVC (Static Var Compensator) has been installed in the high-voltage distribution network until now. On the other hand, reactive power compensation from the low-voltage side using demand side equipment is proposed as a promising alternative with its cost-effectiveness. This paper proposes a method for evaluating the cost-effectiveness of the demand side equipment. We assumed following four installation schemes: (1) the demand side equipment is installed in the same order as PVs (2) the demand side equipment is installed with no relation to PVs (3) the demand side equipment is installed in reverse order of PVs (4) the demand side equipment is optimally installed so that the total capacity is minimized. The proposed method reveals a cost-boundary-value of the demand side equipment where those are widely used, and analyze the changes in the cost-boundary-value under various power system conditions.