Introduction  The objective is to solve the injury and destruction of the wind turbine equipment caused by the common mode interference current and avoid the long-term operation of the wind turbine with faults and the damage to the large components of the wind turbine, which will lead to the decrease of the availability of wind turbines, wind abandonment phenomenon and loss of power generation.

  Method  The article elaborated on the interference signal phenomenon from common mode current, on-site equipment damage, misoperation signal fault, overheating of the current output cable and transformer of the wind turbine caused by faults, equipment misoperation protection, abnormal vibration of the generator set, and other phenomena of a wind turbine in a certain wind farm in southern China. Taking the # 11 wind turbine in the wind farm as the detection point, on-site machine position experiment detection was conducted, and a systematic theoretical analysis of the problem was conducted combined with on-site measurement data and pictures.

  Result  The existence of common mode interference current generated by the conversion system is confirmed, which causes a series of problems such as overheating of current output cable, overheating of transformer, misoperation of protective equipment and abnormal vibration of generator set. As the wind farm project is an online power generation project that has been put into operation for many years, the equipment and cable layout have been in place and fixed, which is difficult to change or disassemble. In order to avoid affecting the normal operation of the generator set, the solution of installing anti-interference coil CoolBLUE® series on the generating busbar of the generator set is adopted without affecting the current situation of the original line.

  Conclusion  The practice shows that this improvement scheme is effective and feasible, it can provide suggestions and ideas for the prevention and improvement of such faults in the future, avoid the similar faults of the wind turbine again, increase the availability of wind power generator sets, and it can be popularized and applied.