Optimal coordinated voltage control in distribution system

Recently, renewable energy technologies such as wind turbine generators and photovoltaic systems have been introduced as distributed generation. The connection of a large amounts of distributed generation causes voltage deviation beyond the statutory range in distribution system. In this paper, we propose a methodology for voltage control using tap changing transformers in distribution system and inverters interfaced with distributed generator. In the proposed method, information about voltage and power is gathered via a network. Based on the information, the optimal reference values are calculated at control center, and sent to transformers and inverters. The proposed method accomplishes coordinated operation among control equipments and improvement against voltage profile. The effectiveness of proposed method is confirmed by simulations.