“…However, when the PV systems were interconnected and operated in distribution systems, many problems related to power quality such as voltage fluctuation in distribution system have occurred [1][2][3][4][5]. Under these circumstances, the power company has installed SVR in order to keep voltages of customers within allowable voltage limits in distribution feeders with PV systems [6,7]. In addition, the distributed generations, renewable energy sources, should be kept at more than 90% of PF in accordance with the grid interconnection codes, and in case of technically necessary, the upper and lower limits of PF should be controlled according to technical guideline of the power company, and also PF of the distributed generations must not become leading PF at the point of distribution system which is lagging PF at distributed generations [8,9].…”