A Hybrid AC/DC Power Flow Solution Including VSC Multi Terminal HVDC Systems by Flexible Unified Branch Model

The hybrid AC/DC network encompasses combination of various types of units such as renewables, conventional power sources, energy storage and loads. It can also cover land and offshore networks. Due to controllability, the hybrid AC / DC network promises high power quality, flexibility and cost-effectiveness. The unified flexible method, which is a method with greater accuracy and flexibility than the sequential method, stands out for power flow calculations in medium and large hybrid networks. Unified methods take quadratic convergence, which gives closer and faster results, but modifications need to be made in AC analysis to solve hybrid networks that include AC/DC converters. In this paper because the hybrid system in facilitating the calculation process and reducing time, the new unified system has tested in solving power flow equations instead of the sequential system and the effect of the new control method on power flow was studied. The results obtained from the study showed that despite the addition of control equipment to VSC in a new model, the new unified model contributed to reducing losses and improving stability.