Evaluation of the accuracy of a thermal rating model to estimate the temperature of operational transmission lines

The CIGRE technical brochure 601 [1] provides tools for calculating the thermal rating of overhead transmission lines calculating. This brochure, which improved upon its predecessor in several aspects [2], also provides methods for dynamic line rating calculations. In order to design a dynamic rating scheme, utilities need to know what is the accuracy of the thermodynamic model of the transmission line. The present publication presents a study where the CIGRE model for line rating was used to estimate the temperature of real transmission lines in the Swiss network, and its accuracy was determined by comparing the results with three years of field data. It is shown that the accuracy of the simulation was improved when a wind cooling expression based on the IEC standard and CIGRE model was…