Impact of short-circuits on overhead line temperature in curative grid operation of 110 kV distribution grids

This paper investigates the impact of short-circuits on conductor temperature in the context of curative grid operation. While previous studies have often neglected this aspect or focused on transmission grids, this work addresses the specific conditions in high voltage distribution grids, where short-circuit behaviour and conductor configurations differ significantly. A simulation-based approach is used to determine the thermal response of conductors during short-circuits, and the results are validated through a measurement in an experimental setup. The study shows that the temperature rise caused by short-circuits depends on fault magnitude, duration, and conductor type. In many cases, this heating effect cannot be neglected. Curative grid operation relies on the fact that thermal limits, not the current rating, determine the maximum line loading. Due to thermal inertia, temporary higher current loading is possible. However, if the conductor is already preheated by a short-circuit, this must be taken into account. Therefore, the paper further analyzes the relationship between permissible higher loading and prefault loading, both with and without considering short-circuit heating. It is shown how short-circuit-induced thermal stress can significantly reduce the available headroom for curative operation. Nonetheless, curative strategies still offer considerable potential for increased grid operation compared to the preventive approach.