Abstract

This paper presents a study that focuses on the evaluation of the analysis of harmonic currents emitted by loads and the harmonic impedance of a real electrical network using the Norton model. The primary advantage of employing this model lies in its ability to address scenarios where the complete network configuration, particularly from the distribution side, is not known. By calculating currents and voltages at the supply-side for two different operating conditions, the harmonic current content and the network impedance can be evaluated. To induce variations in operating conditions, a switching shunt capacitor is utilized. The results show that the fifth and the seventh harmonics clearly appear with values of 189.382 A and 135.073 A, respectively, while the other harmonics have values close to zero. The harmonic impedance also shows the presence of the fifth and the seventh harmonics with values of 1865.681 Ω and 4289.3 Ω, respectively. The main contribution of this paper focuses on converting the real electrical network into numerical data that can be accepted by the software. The components of the network model have to be carefully selected to understand the harmonic analysis and to success the simulation, which is conducted using the EMTP-ATPDraw program. The results of this investigation can be used as a database for electrical transmission and distribution companies in case of making any changes in the network, such as installation of new loads or cables, or in case of making measurements.

Key words: Harmonic current; Harmonic impedance; Norton model, Switching capacitor.