Research of AC/DC parallel wind farm integration based on VSC-HVDC

With wind power taking up an increasingly important share of the total power generation in the system, the larger proportion of wind power have led to problems such as voltage instability, inappropriate power flows etc. The great demand of wind power requires enhanced system capacity, while securing the power quality and AC stabilization. The capacity of VSC-HVDC for fast independent active and reactive power control provides important benefits regarding power quality and successful and reliable system operation. In this paper the parallel AC-DC system for wind power generation is presented. To verify the basic operation principles of operating wind farm and advanced control strategies of VSC-HVDC transmission, the wind farm consisted of five wind turbines with pitch control systems and the VSC-HVDC transmission with relative control systems are modeled by PSCAD\EMTDC to test control algorithms, to identify problems, to investigate different modes of operation of the system and to demonstrate the unique capability of integrating large wind farm to network by VSC-HVDC. Simulation results show that VSC-HVDC transmission is an excellent tool to transmit power from wind farm to a network and at the same time it will contribute to AC stabilization and power quality.