Controlling voltage profile in loop distribution system with Distributed Generation using series type BTB converter

Connecting distributed generations (DGs) into distribution system has presented a challenge of controlling voltage profile in distribution system. In the presence of DGs, voltage profile of distribution system becomes non-uniform and may result in large voltage fluctuation at loads. Therefore, there is need for strict limitation on power injected by DGs. This paper proposes an effective method to overcome the problem of increase/decrease of voltages in distribution system due to the presence of DGs, and it also results in higher permissible power injected by DGs. The proposed method solves the problems by firstly, changing radial to loop distribution configuration. Then secondly, by using series type back-to-back (BTB) converter to control voltage profile of the resulting loop distribution system. Two control nodes in the loop distribution system are used to control the voltage profile. The series type BTB converter is installed at the sending end voltage node of loop feeder. The effectiveness of the proposed method is shown by the improvement of voltage profile and the small size of series type BTB converter. Theoretical analysis is discussed and simulation results are shown to verify the proposed method.