Damping Controller Design in Offshore Wind Power Plants to Improve Power System Stability Using Fractional Order PID Controllers Based on Optimized Exchange Market Algorithm

In this paper, the design of damping supplementary controller in VSC HVDC transmission systems, which is the interface of Offshore Wind Power Plant (OWPP) with the main power system, is studied. First, it is shown that the speed-power curve in a wind turbine affects the damping of oscillation and electromechanical modes of the power system, and depending on the operating conditions of the turbine, the extent of this effect varies. Then, to improve the dynamic stability of the power system, the use of an optimized supplementary controller in the VSC HVDC system will be proposed. The proposed controller is added as an additional loop to the converter control circuits in VSC HVDC and will amplify the damping torque in the generators by correcting the damping coefficient of the system oscillation modes. In addition, a solution is provided to use the supplementary controller in the most optimal path, so that the most controllability on the oscillation modes and the least interference with other channels between the input-output signals are provided. To design the proposed controller, a fractional order PID controller will be used whose coefficients are adjusted through an optimized exchange market algorithm. The optimization of the algorithm is done by using mutation and crossover operators in the genetic algorithm with the aim of avoiding bats being trapped at local extremum. The simulation results show that the method proposed in this paper not only improves the dynamic stability of the power system but also strengthens the voltage profile.