The Simultaneous Influence of the Skin Effect, Environmental Conditions and Variable Resistivity on Current and Temperature Distribution in Overhead Conductors

摘要

In the present work, we have theoretically analyzed the heat conduction of alternating current that flows in a circular electric conductor, taking into account variations of electric resistivity with temperature, which leads to a coupled thermo-electric model. In this approach, we have considered the presence of the skin effect that yields important radial differences of temperature by solving numerically the corresponding Maxwell's equations for the pass of the electrical current, together with the heat conduction equation to predict the radial variations of temperature. The results are presented in dimensionless form in order to reduce the number of physical variables. It is well-known that these high-voltage transmission lines are constructed with aluminum conductors that are composed by strands of the same material. For this reason, trapped-air between these strands complicates the analysis of these phenomena. In this direction, the mathematical model for the heat conduction equation, therefore, takes into account that the air-aluminum system is represented by a porous media. Finally, the imposed thermal boundary conditions reveal that the environmental conditions are a fundamental factor to control the above effects.