Behavior of Energy Dispatch and Line Rating with Respect to Environmental Variables

This paper presents recommendations to the Colombian National Dispatch Center to incorporate the Dynamic Line Rating (DLR) model on energy dispatch in Colombia; these recommendations are based on the characteristics of the critical thermal span (CTS) of a transmission line. To determine the CTS, the rating of a transmission line of Colombia and the energy dispatch of a reference system, which has overloaded lines, were assessed respect to environmental variables. The DLR was the calculation method representing rating lines in relation to environmental variables. In this study, the DLR method proposed in IEEE Std. 738-2012 was programmed in LAB+i; the layer’s diagram of smart grid was a guide to develop calculations of DLR and energy dispatch. Twenty-four case studies were conducted where each of the environmental variables and line current varied and the other remained constant. These case studies were separated into two analysis, assessing the impact on line rating and on energy dispatch, respectively. Variables that have the greatest influence on the line rating (Idyn) were speed and wind incidence angles. Idyn was in a range of values between 0.66 and 2.29 times in the static line rating. Generation costs ranged up to 17.49% in relation to the minimum cost presented and from -5.41% to 11.62% in relation to the cost calculated with SLR. These data allowed establishing the characteristics of the CTS to include DLR on energy dispatch and recommendations to the Colombian National Dispatch Center were suggested.