Journal of Electrical Engineering and Automation

With the large-scale application of wind energy, the application of doubly-fed generator (DFIG) in wind turbines has become more and more common. However, during the long-term operation, problems such as generator shaft current have gradually become prominent, which has brought adverse effects on the stability and operation efficiency of wind turbines. The shaft current is mostly a high-frequency voltage spike generated by the converter, which is coupled to the rotor shaft by means of capacitance, thus damaging the bearing. In this paper, the shaft current and grounding problems of doubly-fed wind turbine are analyzed, and the corresponding monitoring, early warning, maintenance methods and optimization scheme of grounding system design are given. These technical measures can improve the stability and reliability of wind turbine operation.

Double-fed generator; Axial current; Shaft voltage; Generator grounding; Monitoring system; Early warning strategy