Guide for the selection of weather parameters for bare overhead conductor ratings

This Technical Brochure presents the joint CIGRE and IEEE recommendations for selecting conservative weather parameters used in overhead line thermal rating calculations. Its objective is to define practical methodologies ensuring that conductor temperatures remain within safe operating limits while maintaining required clearances, mechanical integrity, and system reliability under adverse weather conditions.

The brochure is based on an extensive international literature review and utility experience, providing guidance for static ratings, study-based ratings, and variable or real-time ratings. It highlights the importance of the correlation between wind speed, ambient temperature, and solar radiation, as well as the influence of terrain and local environmental conditions on conductor…