Estimação da contribuição harmônica de tensão em sistemas elétricos trifásicos.

Abstract

A method has been presented for the allocation of responsibilities between a utility and a customer with reference to the distortion of the voltage waveform of a 3phase electrical distribution system. The measurements necessary for the applications of this method are the voltage and current waveforms at the point of common coupling (PCC) located between the utility and the consumer. The frequencies in the measured waveforms have been estimated and the Kalman filter has been applied to track the phasors of each harmonic component. The phasors are used to estimate the parameters of the electrical system of the load, using the recursive least-squares technique. With the estimated parameters of the consumer’s electrical system and with the information of the equivalent impedance of the utility, a model of the combined electrical system composed of the utility and the consumer is set up. After the modeling of the combined system, a method has been developed that uses the zero, positive and negative sequence components, denominated Percent Harmonic Contribution in Sequence Components (PHCSC). The proposed estimates the percent contribution to the distortion of voltage waveform by the utility and the consumer at the PCC. Furthermore, it is possible to verify the contribution of the harmonic components in unbalanced systems and with more than a consumer connected to the same bus. The proposed method has been applied to waveforms of synthetic systems and also to waveforms measured in an electrical distribution system.