Power System Voltage Harmonic Identification Using Kalman Filter

The intensive use of power converters and other non-linear loads in industry and by consumers in general, has produced an increasing deterioration of the power systems voltage waveforms. The presence of harmonic distortion in power lines results in greater power losses in the distribution systems, interference problem in communication systems and, sometimes, in operation failures of electronics equipments. Owing to these problems and to preserve the power quality, the active filters are used for harmonic elimination. In this filters, a perfect harmonic identification is fundamental, therefore, nowadays many identification algorithms are available, such as, DFT, Fourier series, ect. However, in this work a more robust algorithm based on Kalman filtering is presented. Also, several grid voltage models in state variable are shown, since the Kalman filter needs a model of the evaluated system (in this case, of the grid). Moreover, the advantages of this method with respect to the most used technique, FFT, are commented