A New Algorithm for Energy Measurement at Positive Sequence of Fundamental Power Frequency, Under Unbalanced Non-Sinusoidal Conditions

Abstract

A new algorithm for energy measurement at positive sequence of fundamental power frequency under unbalanced non-sinusoidal conditions is presented. Extraction of a generalized positive sequence from the three-phase signals in time domain is performed first. Then, an accurate extraction of fundamental power frequency tones is obtained taking advantage of Hanning windowing together with interpolation of the FFT results. Active and reactive power for energy measurements are finally calculated via traditional formulas. Errors due to fundamental power frequency desynchronization are analyzed for the proposed algorithm and for two alternative traditional algorithms. Finally, numerical applications to simple case studies demonstrate the usefulness of the proposed approach and the importance of considering the positive sequence of the fundamental power frequency for a correct billing of the energy supplied to the costumers.