ANALYSIS OF COMPOUND FAULT CHARACTERISTICS OF WIND TURBINES STATOR WINDING INTER-TURN SHORT CIRCUIT AND BLADE IMBALANCE BASED ON SPATIOTEMPORAL DISTRIBUTION OF WIND SPEED

Considering the spatiotemporal distribution of wind speed caused by wind shear and tower shadow，the influence of the compound fault of the stator winding inter-turn short-circuit，and the blade imbalance on the electrical characteristics of the doubly-fed induction generator is studied. Firstly，the analytical expression and variation characteristics of rotor current under blade imbalance fault，stator winding inter-turn short-circuit，and compound fault are deduced. Then，the fault simulation model of the doubly-fed induction generator is built on the Matlab/Simulink platform. The experimental test and research are carried out on the doubly-fed induction generator fault simulation platform，which can simulate the equivalent wind speed and rotational speed characteristics. The theoretical derivation，simulation analysis，and experimental research results show that，after considering the spatiotemporal distribution of wind speed，the rotor current contains a modulation frequency of 3kP（P is the rotational frequency of the blade）when the stator winding inter-turn short-circuit fault occurs. When the blade imbalance，the rotor current has P，3kP and its coupling modulation frequency（3k ± 1）P. The rotor current has modulation frequencies P，3kP and（3k ± 1）P around（2 ± s）f and fundamental frequency when compound fault. This paper uses the equivalent wind speed to replace the average wind speed. This research is more in line with the actual operating conditions of doubly-fed induction generator in nature and can provide a reference for fault diagnosis in the actual operation of doubly-fed induction generator. © 2023 Science Press. All rights reserved.