Ampacity Calculation Method for Overhead Conductors in High-Altitude Areas Based on Numerical Simulation

Overhead transmission lines are critical carriers for power delivery, directly influencing the security of the power system. In high-altitude areas, special environmental conditions such as low air pressure and intense solar radiation significantly change the heat absorption and dissipation characteristics of conductors. Therefore, it is necessary to correct the overhead conductors’ ampacity in such areas to ensure safe operation. However, the ampacity calculation method and high-altitude ampacity correction coefficients proposed in existing standards have significant limitations, and there are also large errors in the calculation results. Therefore, based on the system of partial differential equations proposed in the “Guidelines for Calculating the Current-Carrying Capacity of Transmission Conductors at High Altitudes” and the suggestions for high-altitude meteorological parameter modifications from existing standards, this paper establishes a three-dimensional finite element model to study the ampacity calculation method for overhead conductors in high-altitude areas. The results show that a significant thermal shielding effect exists among bundled conductors, and meteorological condition variations significantly influence the temperature distribution of the conductors and their surrounding space. At altitudes of 4000~5000 m, the altitude correction coefficient for both twin-bundle and quad-bundle conductors is −0.06 A∙m−1 under specific conservative conditions.