Skin effect and active resistance of power transmission line wires

The study aims to analyze the skin effect as applied to the active resistance of aluminum wires using a mathematical model based on the theory of electromagnetic fields. The study uses the Elcut finite element simulation software. The simulated object includes round aluminum and cylindrical steel-aluminum wires with a cross-section of 339 mm 2 each, as well as AS 300/39 wire. The nonuniformity of a real power transmission line with steel-aluminum wires is considered. Calculations were verified in the Elcut software by dividing the aluminum wire into two components: a circle with a cross-section of 39 mm 2 and an outer ring with a cross-section of 300 mm 2 . The results of aluminum wire simulation at different harmonics have established a coincidence of the obtained skin effect coefficients with the mathematical model. This coefficient reflects an increase in the active resistance of the wire at the highest harmonic in relation to direct current resistance. For an aluminum wire with a cross-section of 339 mm 2 , the active resistance at the 5th, 7th,11th, and 13th harmonic has increased by 24, 40, 71, and 84%, respectively. This circumstance confirmed the need to consider the skin effect in the assessment of power losses in power transmission lines at higher harmonics. We propose to simulate the AS wire as a cylindrical nonuniform wire consisting of a steel circle inside an aluminum ring. For AS 300/39 wire, the error of determining the skin effect coefficient using this method is below 5% in the studied harmonic range. Thus, the proposed research method considering AS wires as round cylindrical shows the possibility of refining their mathematical model.