Electrical Rotor Fault Detection in Induction Generator under the Influence of Low Frequency Oscillations Caused by Wind Turbine Tower Shadow Effect

In this paper, a method is presented for the electrical rotor fault detection in wound rotor induction generators. The fault is a rotor electrical fault in induction generators employed for wind turbine applications. Due to the tower shadow effect, a stray fault signature is introduced in the generator current which may result in false fault detection. The method is based on the time-frequency analysis in which the frequency is transformed and the time averaging of the signal energy is obtained. The method is known as harmonics order tracking analysis. For reliable fault detection, statistic indices are used in post-processing that increase the ability to distinguish between the fault effect and tower shadow effect. The simulation results illustrate that the proposed method is effectively successful in discriminating these two effects. Finally, the harmonics order tracking analysis is evaluated using the experimental results.