Integrating flywheel energy storage system to wind farms-fed HVDC system via a solid state transformer

As the power of wind farms (WFs) considerably proliferates in many areas worldwide, energy storage systems will be required to dynamically compensate the wind energy intermittency and increase power system stability. In this paper, a backup power conditioning strategy for wind energy-fed voltage source converter HVDC transmission systems is presented. An induction machine based flywheel energy storage systems (FESS) is integrated to the HVDC system via a solid state transformer (SST). The FESS is connected in parallel with the dc-link of the grid side converter; therefore, the excess wind energy can be stored in the flywheel and then restored during the energy-shortage periods. The proposed system aims to compensate the power fluctuations caused by the intermittent nature of wind energy, levels the power-fed to the grid, and improves the quality of delivered power. The proposed system including FESS with an interfacing SST is modeled, simulated, and analyzed in MATLAB/SIMULINK environment. The results verify the effectiveness of the proposed system.