Integration of a DFIG-based Offshore Wind Farm and a PMSG-based Offshore Wind Farm Connected to a Power Grid through a VSC-HVDC Link

This paper presents the stability simulation results of an integration of an offshore wind farm (OWF) based on doubly-fed induction generator (DFIG) and an OWF based on permanent-magnet synchronous generator (PMSG) connected to a large power grid through a high-voltage direct-current (HVDC) link based on voltage-source converter (VSC). These two OWFs are connected to the same AC bus through individual step-up transformers and transmission lines. A damping controller located at the converter station of the proposed VSC-HVDC link is designed by using pole-assignment approach to contribute adequate damping to the studied two OWFs under various operating conditions. A systematic approach using a frequency-domain method and a time-domain scheme is performed to examine the effectiveness of the proposed control scheme. It can be concluded from the simulation results that the proposed VSC-HVDC link joined with the designed damping controller located at the converter station can not only render appropriate damping to the modes of the studied OWFs under various operating conditions but also effectively mitigate inherent fluctuations of the power injected to the power grid.