Research on low voltage ride-through strategies for doubly-fed wind farms during asymmetric faults

Abstract

This paper addresses the issue of enhancing the low voltage ride-through (LVRT) capability of doubly-fed wind farms during asymmetric faults. This research is of critical importance for ensuring the safe and stable operation of the power grid and the sustainable development of wind power technology. Given the stricter LVRT requirements set by the latest national standards in China, existing schemes are insufficient to meet these challenges. This paper first analyzes the control performance of the rotor side converter under asymmetric fault conditions. Based on national standard requirements, the availability of STATCOM, optimized operation targets, and converter voltage and current limitations, an optimized LVRT scheme is proposed. Validation through PSCAD simulations demonstrates that the proposed scheme effectively meets the national LVRT operation requirements. It also shows significant advantages in reducing electromagnetic torque fluctuations, enhancing active power output, protecting converters, and mitigating power fluctuations during faults. The innovation of this research lies in proposing a multi-target coordinated LVRT strategy, providing a new technical approach for improving the LVRT performance of wind farms and the stability of power grid operation.

Keywords

• Asymmetric fault
• Reactive current compensation
• Low voltage ride-through
• Double-frequency fluctuations
• Doubly-fed induction generator (DFIG)