State Criterion of Wind Turbine Generator in Operation with Using Tower Shadow Effect

Abstract

Because of low cost and maintenance free, inductron machines are widely used as the wind turbine generators. In order to get wind energy effectively, pole-change-type induction generators are adopted. Otherwise, the pole-change-type induction generator causes the voltage dips at starting and at pole changing time. To keep the power quality, it is important to know the state change of the generator operation.
In this paper a new state criterion of wind turbine generator in operation using the tower shadow effect, which is the oscillation of active power caused by a drop in rotation torque of the wind turbine when the tower of the wind turbine and the blade of the turbine overlap each other, is proposed. By using the developed method, the state of the wind turbine generator can be judged using the short period oscillation frequency of the active power of the wind turbine generator.The developed method is applied to measured data, and it is found that the developed method is effective in the state criterion of the wind turbine generator. It is also found that the moving average method is one of the efficient methods to suppress the fluctuations in the trend of error, namely, the deviation of the frequancy of the wind turbine generator.