Statistically determined static thermal ratings of overhead high voltage transmission lines in the Rocky Mountain region

Static thermal ratings of overhead high voltage transmission lines are fundamental and indispensable components in assessing the capability of an electrical network to assure its reliable operation. Traditional methods of determining static thermal ratings hinge on the presumption of specific weather combinations. The results are conservative static thermal ratings without a strong correlation to the prevailing weather patterns in a region. This paper delineates an adaptable methodology for establishing overhead static thermal ratings based on a statistical analysis of historical weather observations. Use of the methodology adds practical knowledge and understanding to the development of static thermal ratings, and the resultant static thermal ratings have a realistic relationship to the weather patterns in a region. Use of the methodology also allows the system to be designed and operated to a specific level of risk.