A Practical Method to Identify Contributions of Harmonics in Power Systems: Method and Application

Abstract

This paper presents an approach to quantify the contribution of harmonics between the power utility and customers connected at the Point of Common Coupling (PCC). This method is based on the determination of Thevenin’s equivalent circuit at both sides of power utility and customers. This paper describes the steps of harmonic determination of such Thevenin equivalent circuit that does not depend on current injection process or downtime. The Thevenin equivalent circuit is calculated using measured voltages and currents occurring at different times at the PCC when the load changes. With the Thevenin equivalent circuit, the individual contribution of harmonics between utility and customers can be calculated in the power system. A case study of the metropolitan municipality in Johannesburg is presented to demonstrate the application of this method. Results of study conducted between a sport stadium and metropolitan Johannesburg Company indicated the presence of 5th, 7th and 11th harmonic at the PCC mainly injected by the sport stadium.