Planetary gearbox torsional vibration effects on wound rotor induction generator electrical signatures

Recently, alternative non-invasive methods based on electrical signature analysis have been proposed as an effective, easy and cheap way for electrical and mechanical faults detection in complex electromechanical systems such as wind turbines and traction systems. This paper aims to study the torsional vibration effects of a planetary gearbox which is a vital component of wind turbines on the electrical signatures of a wound rotor induction generator through both numerical simulations and experiments. A lumped model of planetary gearbox which needs minimum number of mechanical parameters is linked to the classical model of wound rotor induction generator in abc reference frame. The numerical simulation results show that some of mechanical characteristic frequencies of the planetary gearbox can be identified in the electromagnetic torque and stator current signatures of wound rotor induction generator. A reduced scale wind turbine simulator based on a 5.5 kW wound rotor induction generator is used for experimental verification of the proposed model at different working conditions.