A two-stage multi-objective optimal power flow algorithm for hybrid AC/DC grids with VSC-HVDC

A novel two-stage multi-objective optimal power flow (MOPF) approach is proposed to coordinate the economy, voltage stability, and environmental requirements for hybrid AC/DC grids with VSC-HVDC. First of all, based on the steady-state characteristics of AC/DC grids, a MOPF model considering environmental benefits and voltage stability is built. Then, a new two-stage approach incorporating multi-objective optimization and decision support is proposed for solving the model. At the first stage, NSGA-II with a hybrid coding scheme is employed to obtain the Pareto-optimal solutions; at the second stage, the obtained solutions are firstly clustered into three groups using fuzzy c-means (FCM) clustering algorithm, and then the relative efficiencies of the solutions belonging to the same group are evaluated using super-efficiency data envelopment analysis (SEDEA) to help decision-makers choose the recommended compromise solutions. And finally, the validity of the presented approach is verified based on the test results of the IEEE 14-bus system.