Abstract
This paper treats the problem of voltage control and balancing of the unbalanced three-phase loads in distribution systems with Distributed Generators (DG) and tap change transformers. The DGs considered in this paper are supposed to be Photovoltaic (PV) generators, due to the growing demand of renewable energies. Unbalanced three-phase loads operation can have undesirable effects on the distribution system components, beside making the voltage control more difficult. For that reason, the proposed method aims to balance the unbalanced three-phase loads and control the voltage using the available reactive power generated from the DG through the inverters interfaced with PV modules. The Newton Raphson method is used solve the unbalanced three phase power flow equations of the distribution system, while the three phase elements models are considered. Twenty-four-hour data are used to simulate a 14-bus distribution system with unbalanced three-phase loads in 7 nodes to verify the effectiveness of the method. The simulation results show that the node voltages are balanced and kept within the statutory range.