Power system usually have standard static ratings (SLR) that determines load constraints. It refers to the maximum allowable conductor ampacity pre-determined by worst-case conditions (high ambient temperature, maximum solar radiation, and low wind speed) of their overhead transmission lines, that rises the line’s temperature without infringing ground clearance and causing loss of conductor tensile strength. Line’s dynamic capacity is created as an alternative to standard constant rating that is designed with reference to extreme weather and load conditions. Dynamic line rating allows assets the real power line’s operating capacity using available information on weather conditions. DLR is hence often more flexible than SLR, that have a chance of extending capacity of existing power lines for some periods of time with favorable weather conditions for transportation higher electrical power capacity from production site to the load. This paper investigates the possibility of using dynamic line rating (DLR) to expand the existing power transmission capacity of overhead lines which can be implemented on 220 kV transmission lines in Vietnam, especially in some line areas with high-density of renewable energy integration. This work applies a DLR caculation models to determine the power lines’ additional theoretical ampacity obtained by using this methodology for a Ninh Thuan region with distinct conditions regarding i) weather database, ii) topography and iii) wind and solar power resource. The results show that the dynamic rating is predominantly higher than the static rating, which potentially enhances the system’s reliability. This research provides a comprehensive study of literature on dynamic line rating, current constraints on the power system based on the geography of Vietnam, and analysis in Python and Matlab environment of real-time weather databases applied to dynamic rating on a proposed case study.