Method for Detecting Faults in DFIG Generator Slip Rings Based on Current Signature Analysis via Goertzel Algorithm
Wind Power Generation. DFIG. Current Signature. Goertzel.
In recent years, the search for electricity generation from renewable sources has grown in Brazil and worldwide. One of the electricity sources that stands out in this process is wind power. Generally, this type of generation is implemented using conversion systems based on machines such as DFIG (Doubly-Fed Induction Generator), PMSG (Permanent Magnet Synchronous Generator), or SCIG (Squirrel-Cage Induction Generator). Among these topologies, DFIG wind turbines stand out because the back-to-back converter processes only a portion of the machine's power. DFIGs are susceptible to electrical faults, including slip-ring faults, which can be diagnosed using current signature analysis techniques. The most popular method is frequency spectrum analysis obtained by FFT (Fast Fourier Transform). However, an alternative, with lower computational cost, is the Goertzel algorithm. In this context, this master's thesis proposes using the Goertzel algorithm to identify specific spectral components associated with slip-ring failures in rotors. The slip ring defect is emulated from the rotor resistance asymmetry of the DFIG. Simulation and experimental results are presented and demonstrate the effectiveness of the proposed methodology.