Climate-Driven Ampacity Analysis of High-Voltage Power Lines

This study evaluates the impact of projected climate change on the thermal performance and reliability of high-voltage overhead transmission lines in Central Europe for the 2025–2050 period, with a focus on Hungary. First, the CIGRE conductor thermal model was analyzed to quantify the sensitivity of line ampacity to meteorological input parameters. Wind speed, solar radiation, and ambient temperature were identified as the dominant drivers of line rating variability. Historical trends over the past 20 years were then assessed using data from multiple meteorological stations distributed across Hungary.

Thermal simulations were performed for five 400 kV transmission lines traversing different climatic regions of the country. Changes in ampacity were evaluated both in terms of mean values and the 5th percentile, the latter serving as a proxy for conservative static line rating

(SLR) conditions. The results reveal spatially heterogeneous trends in line ratings, reflecting regional differences in climatic evolution.

Future projections were derived using the CORDEX regional climate modeling framework, specifically the ALADIN63 model, for the period 2024–2050. Raw climate model outputs were bias-corrected against observed data using change factor method (CFM) to improve local representativeness. Ampacity simulations were conducted under two greenhouse gas concentration scenarios, RCP4.5 and RCP8.5. The projected trends reinforce the historical findings, indicating a continued increase in thermal stress on overhead lines, with extended periods of high temperatures encroaching into transitional months such as May and September.

The results highlight the growing importance of dynamic line rating (DLR) systems as a climate adaptation measure. As a practical outcome, this study demonstrates that long-term trend analysis enables the definition of region-specific ampacity zones even within a relatively small country. Three distinct ampacity zones were identified for Hungary, supporting a more gradual and informed transition between static and dynamic line rating approaches. This represents a meaningful step toward rethinking ampacity assessment practices and systematically incorporating climate change impacts into transmission system operation and planning.