Research on VSC-HVDC system to mitigate power output fluctuation caused by wind farms

With global environment problems increasing, wind power as a renewable energy is concerned worldwide, many wind farms are designed recently, however, the power output of wind farms is fluctuant which is determined by the intermittent and random of wind speed. With the increase of wind farm capacity and the percentage of wind power in the whole power system, the influence of the power output fluctuation of wind farms for the system stability will be more remarkable. The paper describes the use of VSC-HVDC technology to mitigate power output fluctuation caused by wind farms based on doubly fed induction generators (DFIGs) which dominate in large capability wind generators, stator flux oriented vector control technology and capturing maximal wind energy are adopted, the independent control of active and reactive power is realized and wind generation by capturing maximal wind energy with efficiency is also obtained. The coordinated control strategy between wind farms and VSC-HVDC system is presented, the active power and reactive power fast regulation of VSC-HVDC system keeps the injection power of AC system a stable value according to the system needs. The simulations performed in PSCAD/EMTDC to verify the proposed control strategy.