A Series Type BTB Converter for Controlling Voltage Profile in Loop Distribution System with Distributed Generations

Connecting Distributed Generations (DGs) into distribution system has presented challenge of controlling voltage profile in distribution system. The presence of DGs makes voltage profile non-uniform and may result in large voltage fluctuation and over-voltage 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 voltage in distribution system due to the presence of DGs, and it also realizes higher permissible power injected by DGs. In the proposed method, the configuration of distribution system is changed, firstly, from radial to loop type by tying the receiving ends of feeders. Secondly, a series type Back-To-Back (BTB) converter is installed near substation to improve voltage profile by controlling the voltages of the two nodes in the looped feeders. The effectiveness of the proposed method for improvement of the voltage profile and reduction of the converter capacity is presented.