Power line dynamic rating: forecasting potential period of low wind speed is crucial

The replacement and building of new electrical power lines (50 000 km in Europe) can’t cope with the growth of RES development in EU for the ten upcoming years. New solutions have to be found to manage such power transmission needs. Dynamic Line Rating (DLR) systems are part of the global solution. They allow to increase the power line capacity by an average 20% over the static rating (which is defined as the maximum current-carrying capacity as designed). The ampacity or thermal rating, is calculated thanks to (i) sensors installed directly on the power line conductors, like Ampacimon, (ii) weather data, and (iii) standard thermal models (IEEE, CIGRE). However, in order to be fully effective and to allow an efficient use of assets, ampacity calculation in real-time is not enough; it has to be forecasted as well. Beyond 6h-forecast, weather forecasts are necessary to compute the line ampacity up to two days ahead, as needed by network operation. As wind convection has a major impact on conductor cooling, even low wind speeds (2m/s up to 5m/s) allow a huge ampacity increase (the actual rating can be doubled). Therefore, low wind speed forecast up to 2-days ahead finds a major application in dynamic rating of overhead transmission and distribution lines