Evaluation of LVRT Control Strategies for Offshore Wind Farms

The penetration of offshore wind farms (OWF) connected to the electric utility grid through voltage source converter-based high-voltage DC (VSC-HVDC) increased year by year in some countries. However, penetration of HVDC-connected OWF affects electric power system voltage and frequency stability during a grid disturbance, which enforces system regulators to update their grid code regulations for secure and stable operation. Low voltage ride through capability (LVRT) for OWF ensures that OWF stays grid connected during a voltage disturbance and supports the electric grid during such low-voltage fault events instead of direct tripping. Several LVRT strategies for HVDC connected OWF are reported in the literature, however, without considering a critical factor of active power recovery (APR) ramp rate requirements. In this paper, three LVRT strategies have been investigated to comply LVRT and APR requirements. The different LVRT strategies for OWF considered in this study were tested under different scenarios in IEEE 39 bus benchmark system, and a comparative analysis of these LVRT strategies has been reported in this paper.