Extended Park's vector method in early interturn short circuit fault detection for the stator windings of offshore wind doubly-fed induction generators

Abstract

To avoid dramatic economic losses and unrecoverable failures in offshore wind farms, it is necessary to accurately detect faults at the early stage of doubly-fed induction generators. The new extended Park's vector method is proposed in the study. The amplitude of the twice fundamental frequency component of the square of the Park's vector module is selected as the new fault feature to realise the early fault detection. The relationship between the extended Park's vector method and negative sequence current of the stator is also analysed in the study. The Fryze-Buchholz-Dpenbrock algorithm and the nonlinear least squares method are applied to estimate the mathematic relationship among unbalanced stator voltage, load change and the negative sequence current of the stator. The experiments were conducted and the results showed that the proposed method is robust to the effects of the unbalanced stator voltage and load change. Therefore, the proposed method can accurately detect faults at the early stage with high sensitivity and reliability.