Wavelet-based method for detection of electrical and electromechanical oscillations in synchronous generators

This paper proposes a real-time wavelet-based method to detect both high-frequency electrical oscillations and low-frequency electromechanical oscillations in synchronous generators of salient poles during faults on the grid. By using the discrete wavelet transform, the spectral energy of a time-domain signal is decomposed in scaling coefficient energy and wavelet coefficient energy. Using the active power of the synchronous generator, the wavelet coefficient energy of a compact mother wavelet can provide the fault detection with no time delay, whereas the scaling coefficient energy can provide the low-frequency electromechanical oscillations. The performance of the proposed method was assessed in an experimental power system, and various mother wavelets were evaluated.