Fan is a kind of fluid machinery which transforms the mechanical energy of prime mover into the pressure energy and kinetic energy of the transported gas. It belongs to the category of general machinery. Fans are widely used in metallurgy, chemical industry, textile, light industry, electric power, coal, petroleum, machinery, building materials, agriculture and other production departments of the national economy. In the production practice, when the fan is not in the maintenance cycle, some faults often occur, which makes the production department have to stop for maintenance, which causes the loss of production and increases the maintenance cost. In addition, it is also possible that the fan can still operate normally in the maintenance cycle, but due to institutional reasons, it must be shut down for maintenance, resulting in the so-called "maintenance surplus", which will cause economic losses in both aspects.
In order to prevent the sudden accidents of the fan, eliminate the excessive maintenance of the equipment, and reduce the dynamic load of the fan, during the operation of the fan, the condition monitoring device is used to monitor the operation status of the fan and analyze its abnormal data regularly. In case of failure, timely measures should be taken to prevent accidents and ensure safe and economic operation of the fan.
Because the current sensor is necessary in the wind power generation system, in the actual fault diagnosis system, there is no need to install additional sensors to obtain the signal. Therefore, the electrical signal fault diagnosis method has its unique advantages in the fault diagnosis of wind turbine. This paper mainly studies the basic principle of current signal analysis to judge the fault of the main drive chain of wind turbine, and analyzes the current signal sent by the wind turbine experimental model through wavelet analysis, which proves that the fault of the main drive chain of wind turbine can be diagnosed through the current signal of the generator.
1、 Fault diagnosis principle of main drive chain of wind turbine
Since the torque transmission loss rate of large synchronous generator is about 4%, if the torque loss in the process of energy transmission is ignored, the torque TP generated by wind turbine and the electromagnetic torque TG generated by synchronous generator can be regarded as approximately equal
