Integration of Onshore Wind Farms to a Weak AC Grid Interfacing LCC HVDC Transmission

Abstract

This chapter presents three case studies relating challenges of interfacing doubly fed induction generator (DFIG)-based onshore wind farms in weak AC grids with line-commutated converter (LCC) HVDC. The first study focuses on modeling and analysis of the impact of inertia and effective short circuit ratio on control of frequency in such weak grids. In the second study, coupling between frequency dynamics of the AC systems on both inverter and rectifier side of LCC-HVDC with the rectifier station operating in frequency control is studied, along with the presence of large DFIG-based wind farms on the weak rectifier-side grid. The third study illustrates the effectiveness of converting conventional generators to synchronous condensers to improve frequency dynamics in weak grid systems following loss of infeed from a wind farm. The effectiveness of secondary frequency control through LCC HVDC is also investigated.