Fault-tolerant control of a wind turbine with a squirrel-cage induction generator and stator inter-turn faults

Abstract

Faults of wind turbine generator electromechanical parts are common and very expensive. This paper introduces a fault-tolerant control scheme for variable-speed variable-pitch wind turbines that can be applied to any type of generator. We focus on generator stator isolation inter-turn fault that can be characterized before triggering the safety device. A simple extension of the conventional control structure is proposed that prevents the fault propagation while power delivery under fault is deteriorated as less as possible compared to healthy machine conditions. Presented fault-tolerant control strategy is developed taking into account its modular implementation and installation in available control systems of existing wind turbines to extend their life cycle and energy production. Simulation results for the case of a 700 kW wind turbine are presented.