A sensitivity analysis of Dynamic Thermal Rating procedures using a probabilistic Monte Carlo approach

The Dynamic Thermal Rating (DTR) algorithm proposed in this paper combines the CIGRE thermal model of conductors with a complex multi-span mechanical model of the line that takes into account the mechanical interaction between spans, due to the possible rotation of strings, and that the temperature of conductors can vary span by span, for different weather conditions. The developed tool is able to forecast the time trend of conductor temperatures, tensions, sags and clearances at each span. Since the weak point of DTR algorithms is the proper forecast of weather conditions about to be present on the different spans of the line, this paper investigates the possibility of using a probabilistic approach to assess the robustness of the thermal and mechanical outputs of the DTR procedure. A sensitivity analysis of results is carried out considering many different weather scenarios, properly drawn and weighted by a Monte Carlo technique. A case study based on a 400-kV overhead transmission line is shown and discussed.