Reactive Power Management in Offshore Wind Farms by Adaptive PSO

According to the new grid codes, wind parks must operate similar to other conventional power plants. Offshore wind parks are connected to the main grid with long cables and reactive power management is a big concern to the operators in the changing wind power conditions. This paper addresses the optimal reactive power dispatch (ORPD), which is a mixed-integer nonlinear optimization problem. The integer variables in ORPD are tap positions of the transformers, switching of cables and switched reactors, if present. A new adaptive particle swarm optimization (APSO), which is free from tuning of population size and is based on different sized groups of particles called "Tribes", is used to solve the ORPD problem. The proposed APSO is embedded in the Newton-Raphson load flow program. The effectiveness of the proposed algorithm is demonstrated on a real offshore wind farm, which is currently in planning stage, in Germany.