Adaptability of Traditional Transformer Protection in Offshore Low-Frequency Wind Power Systems

The second harmonic restraint ratio differential protection is commonly used to prevent maloperation due to inrush currents. However, in offshore low-frequency transmission systems with power electronic equipment at both ends, grid faults may cause current distortion, reducing the protection’s effectiveness. This study focuses on analyzing the adaptability of this protection in offshore low-frequency wind power systems. Using the Half-Wave Fourier Algorithm, the fundamental phasors of differential and restraint currents are extracted to assess protection performance during faults. The study builds a PSCAD model of the system and validates the protection algorithm’s feasibility with MATLAB. Simulation results confirm that the protection principle operates quickly and reliably under all fault conditions in low-frequency transformers.