A COMPARATIVE EVALUATION BETWEEN FREQUENCY ESTIMATION ALGORITHMS FOR POWER QUALITY ASSESSMENT IN DSP.pdf

XVIII IMEKO WORLD CONGRESS Metrology for a Sustainable Development September, 17 – 22, 2006, Rio de Janeiro, Brazil A COMPARATIVE EVALUATION BETWEEN FREQUENCY ESTIMATION ALGORITHMS FOR POWER QUALITY ASSESSMENT IN DSP IMPLEMENTATION Václav Matz1, Pedro M. Ramos2, Nuno B. Brás2 and A. Cruz Serra2 1 Faculty of Electrical Engineering, Department of Measurement, Czech Technical University, Technicka 2, 166 27 Prague,Czech Republic e-mail: matzv@fel.cvut.cz 2 Instituto de Telecomunica??es and Department of Electrical and Computer Engineering, Instituto Superior Técnico, Technical University of Lisbon, IST, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal Phone: +351-218418485 Fax: +351-218418472 e-mail: Pedro.Ramos@Lx.it.pt Abstract: Numerous frequency estimation algorithms are available for power quality assessment of frequency. In this paper, a comparative study in terms of accuracy, number of operations and memory cost is presented to select the best solution for implementation in a digital signal processor, in the context of typical power quality frequency disturbances measurements. 2. ALGORITHMS In this section, the different algorithms that will be compared are described and their main advantages and disadvantages are presented. The input power signal is digitized with an Analog to Digital Converter (ADC), with a total of samples, acquired at the sampling frequency N Keywords: Frequency estimation, power quality assessment. Sf . 2.1. FFT 1. INTRODUCTION The FFT algorithm is one of the simplest ways to estimate a signal frequency. However, when the objective is to estimate time-varying frequency, it has strong limitations because of its spectral resolution. In fact, the spectral resolution Frequency estimation algorithms for time-varying frequency signals have been analyzed due to its transversal application in electrical and electronics engineering. In particular, many algorithms were developed for power quali