Validation of a thermal model for overhead transmission lines at high conductor temperature

Incorporating a growing number of renewable energy sources into the existing transmission grids will require an optimal use of the network infrastructure. For transmission lines which are limited by a maximum conductor temperature, the maximum current capacities can be optimized by implementing a Dynamic Line Rating (DLR) scheme. In a DLR scheme the current (or predicted) weather conditions are input to a thermodynamical model of the transmission line, and the output of this model is the present (or future) maximum current capacity of the line. Nevertheless, several transmission system operators are concerned about the reliability of the thermal model at high conductor temperatures. In this contribution, the new outdoor test facility for conductors which was built in ETH is presented. Then, using data acquired in this facility, it is shown that the thermodynamical model introduced here provides a satisfactory description at high conductor temperatures.