MEDIÇÕES DE POTÊNCIA SEGUNDO AS TEORIAS DE POTÊNCIA CONSERVATIVA (TPC) E IEEE 1459-2010 IMPLEMENTADAS COM REDUZIDA TAXA DE AMOSTRAGEM

Abstract

This paper presented two modern power theories: Conservative Power Theory (CPT) and IEEE 1459-2010 Power Theory, aiming for the improvement of the algorithms responsible for power calculations using reduced sample rate, lower than 300 Hz. In order to achieve such sample rate that incurred calculation with acceptable accuracy and precision, it was necessary to build a project. Within computer simulations made with 8 kHz sample rate, it was noticed errors lower than 5 percent, hence, calculation were made to discover a sample rate lower than 300 Hz, even though, with the same amount of samples of 8 kHz. Beyond active and reactive power, new power measurements were included, considering unbalanced loads and waveform distortions, and their mathematical methods were described as well. Computer simulations were performed using the theories in discrete time domain for an unbalanced RL three-phase circuit and for an unbalanced non-linear three-phase circuit. Afterwards, hypotheses testing were done for each power measurement, that assured acceptable accuracy and precision using a sample rate lower than 300 Hz. Among the thirty one power measurements, the mean percentage errors were smaller than 5% in 70% of the cases and smaller than 2% in 61,3% of them. Hence, a computational cost drop was fulfilled for power calculations.