Load Flow Analysis for AC/DC Distribution Systems with Distributed Generations

Hybrid AC/DC distribution systems are rapidly growing due to the recent developments in power electronic technologies and increasing deployment of DC output type distributed generations (DGs) in distribution voltage levels. The presence of DGs in DC distribution systems imposes new challenges in load flow calculations. In response, this paper is dealing with the load flow calculation problem in AC/DC distribution systems in the presence of different kinds of DGs. For this purpose, mathematical models of different kinds of DGs are presented, and then, the models are incorporated into the sensitivity matrix method for using in load flow calculations. Since the large number of load buses and the high R/X ratios in the AC part of the system can lead to the divergence of Jacobian matrix based methods, the suggested method is based on backward forward sweep (BFS) method. The proposed method is simulated on a test system equipped with different kinds of DGs and converters and the results are presented.