Impacts of dynamic line rating on power dispatch performance and grid integration of renewable energy sources

The potential benefits of employing dynamic line rating (DLR) for the grid integration of variable renewable energy sources (RES), such as wind and photovoltaic (PV) units, are presented and analyzed. Unlike nominal line rating (NLR), DLR takes advantage of the fact that the physical power transmission capacity of overhead lines is a function of ambient conditions (temperature, wind speed, wind angle and solar insolation). DLR is hence often less conservative than NLR, which assumes more challenging ambient conditions. A simulation study has been performed on a functionally modeled six-node benchmark power system loosely based on the German power system. Simulations with high time resolution were accomplished using a predictive power dispatch scheme that directly incorporates line constraint information. Historic load demand, wind and PV in-feed profiles, as well as scaled-up profiles for high RES scenarios are used. Dispatch impacts of line constraints derived via DLR and NLR are compared and their effect on RES grid integration is assessed.