Damping Oscillation Techniques for Wind Farm DFIG Integrated into Inter-Connected Power System

摘要

According to the new international grid codes, ancillary services from renewable energy sources are essential, especially when these sources are harnessed as distributed generators. Power oscillation damping (POD) is a supplemented feature needed from wind power plants. This paper investigates different control techniques that can support wind farms based on a doubly fed induction generator (DFIG) with the proper POD. A damping control loop (DCL) is inserted into the control circuit of the back-to-back converter of DFIG to enhance system oscillation damping. The main function of DCL is similar to that of the conventional power system stabilizer. However, under congestion situations, external regulation devices such as STATCOM are required to support system performance and maintain wind farms tracking grid code requirements. A 2-area 4-machine system which consists of three thermal power plants and one wind power plant is examined. The dynamic performance of the system is investigated using power system stabilizer (PSS) as an embedded feature with the control circuit of the thermal power plants. A comparison between the PSS and STATCOM based on system dynamic performance is performed using MATLAB/Simulink. Additionally, the particle swarm optimization technique is used to enhance the performance of the proposed control techniques, taking the voltage stability margins into consideration.