Research on cable selection in low voltage distribution systems affected by harmonics

In low-voltage distribution circuits, when the load carried by the power supply system is a three-phase balanced load, the current in the circuit contains third harmonic, and the selection of cable cross-section needs to consider multiple factors. When the third harmonic content of the circuit reaches a certain value, when considering the cable cross-section, it is necessary to calculate the current carrying capacity, the setting value of the protective device connected to the cable, and the influence of different harmonic contents. Under different harmonic contents and equal cross-sections of neutral and PE lines, cables may be selected according to the interface of phase or neutral lines. In this article, the cable cross-sections are calculated and studied from the above three aspects, and quantitative analysis is combined with practical cases to provide reference for the selection of low-voltage cables in the power supply and distribution industry.