LVRT Test Bench for Wind Turbines Based on Virtual Voltage Divider

With high penetration of wind energy, the low voltage ride through (LVRT) ability of wind turbines (WTs) connected to the grid is included in recent grid codes. A novel LVRT testing method for full scale power converter WTs and the corresponding control strategies are proposed in this paper, which can emulate different types of grid faults. A virtual voltage divider is presented to realize linear control of the point of common coupling (PCC) voltage during the asymmetrical fault and makes the PCC voltage fit the standard LVRT voltage profile accurately. To validate the control strategies, a regular 2MW permanent magnet synchronous generator (PMSG) with the full scale power converter connected to the VSC-based test bench is modeled in PSCAD/EMTDC. The simulation results have shown that LVRT testing for wind turbines under different grid faults can be realized by utilizing the proposed bench.