PMSG fault identification applied to wind power

Wind farms consist in many midsize generating units. The height of equipments, their placement and the ongoing tendency to put them offshore require monitoring at distance. The technology to convert wind energy with permanent magnet generators is widely used in wind energy systems, despite the fact that this electric machine is one of most recent generators on the market. The goal of this paper is the proposal and the experimental validation of voltage and current signatures to detect incipient faults on PMSG (Permanent Magnet Synchronous Generator). The three faults discussed in this paper are the stator turn-to-turn fault, the permanent magnet demagnetization and the rotor eccentricity. The short circuit fault between turns was determined by analyzing the signature of the third harmonic voltage and its multiples. The proposed methodology is able to detect the faulty phase despite the presence of a third harmonic caused by machine asymmetries and asymmetric loads. The use of multiples of the third harmonic is essential for that. Regarding the permanent magnet demagnetization, the detection was made by measuring the voltage waveform of a stator derivation coil. The current signature method proposed can detect the static eccentricity, even in the prototype that has low inductance and large air gap, typical characteristics of midsize generating units for wind farms.