Harmonic distortions are not new problems in electrical power systems. However, electrical networks have undergone several changes in recent decades, such as the wide range of electronic devices (converters, control devices, etc.), and those equipment produce emission of harmonic currents. The investigation of the contribution of several sources of harmonics in power systems is essential, considering that it is a problem of power quality that cannot be neglected. Thispaper aims to investigate the aggregation of harmonic currents in a 230kV TBE/Eletronorte system. For this, the transmission system was modeled using MATLAB/Simulink software with the typical values provided by TBE. A vectorial analysis was performed for the three-phase system and a sum analyzes of harmonics from different sources on Phase A, to estimate the influence of those current sources on Castanhal and Guama buses, when a harmonic spectrumis present on Vila do Conde and Utinga buses. In both analyzes, a phase angle spectrum of 10 and 20 degrees was applied in the harmonic source of Utinga. The summation analyzes proved to be useful because it can estimate values that harmonic currents can assume, for different conditions, and can be very useful in the planning stage to avoid estimation errors.
