Wavelet-based protection assessment of the doubly-fed induction generator

Abstract

With the globalization and the rapidly increasing global energy demand, it has been seeking the sustainability guarantee because the growing concern to preserve the planet for future generations. Therefore, investments in clean and renewable energy sources, such as wind power generation, have gained space in research groups in order to overcome their drawbacks and improve the benefits. The doubly fed induction generator (DFIG) is the predominant one in the market of the wind energy. Nevertheless, considering the electrical failures inherent to this generator type and the ones in the power system (PS), the protection of its elements is an important topic that still does not have comprehensive studies. This dissertation DFIG electrical signals in case of machine terminal faults are analyzed and evaluated using the real-time stationary wavelet transform with boundary effect (RT-BSWT). Furthermore, qualitative studies on wavelet overcurrent, wavelet under-voltage, directional, and differential protections will be introduced in order to assess these new protection trends applied to wind energy conversion systems (WECS). Therefore, these protections are verified in order to analyze if they work correctly when applied to a DFIG. Furthermore, analysis applying these protections to real signals, collected by an experimental test-bench with DFIG, demonstrated which the used mathematical tools had good performances for protection against electrical faults at the common connection point (PCC).