Fault Diagnosis of Stator Inter-Turn Short Circuit in Doubly Fed Induction Generator of Wind Turbine

A model-based method for the diagnosis of the Stator Inter-Turn Short Circuit (SITSC) fault in Doubly Fed Induction Generator (DFIG) of wind turbine is proposed in this paper. The state space model of the generator with taking into account the SITSC fault is presented in the stationary reference frame noted (alpha, beta). The proposed diagnosis approach has the advantage to not only allow the fault detection but also the identification of the affected stator phase and the determination of the fault level. The fault is detected by generating and analyzing the residual signals of stator electrical currents. The residuals are the estimation errors between the DFIG currents given by the model and the currents estimated by the Linear Kalman Filter (LKF), since the established model of DFIG is a Linear Parameter Varying (LPV) model. The opened feedback loop of the LKF is used for fault identification. Firstly, the impact of the studied fault on the stator currents, the rotor currents and the mechanical speed of the generator is presented in this paper. The main contribution of this paper is the use of a single Kalman observer for accomplishing the three diagnosis steps of the Stator ITSC fault. The simulation results show the effectiveness of the proposed approach in the diagnosis of a small and a high value of the ITSC fault in the generator stator windings.