Abstract
Traditionally, thermal current rating of transmission line is considered as a constant. It is defined considering the most severe weather condition of the season. Actual weather condition, however, changes from time to time. Therefore, actual thermal rating should be changed from time to time. It leads to the concept of “dynamic rating". Short term rating of the transmission line may be changed dynamically from time to time according to the power flow and weather condition in the concept of dynamic rating. Detailed calculation method of dynamic rating is discussed in this paper. Furthermore, new subtransmission system operation method based on the dynamic rating of transmission lines is proposed in this study. The effects of the proposed operation on supply reliability and transmission line life are also evaluated.
