Overheating of the power transmission lines can cause faults, leading to interruptions on the power distribution system. This temperature rise may cause more significant failures in the medium and long term. Symptoms of these faults occur early in the transmission line with small temperature increases or changes in current/voltage values. Current/voltage changes in very high-, high-and medium-voltage lines may not be detected in cases caused by uninterrupted failures. Electrical, insulation, and mechanical failures occurring in the power transmission line cause an increase in the temperature. Although the temperature change occurring on the line is generally neglected within the tolerance values, it may lead to significant failures and cause material and labour losses. In this study, the temperature of a power transmission line was measured by a line-inspection robot, transmitted to a remote control center, and time, location, and temperature changes were recorded along the line. The temperature profile of the line was created using these data and made it possible to predict any faults that may occur in the future. It helps to detect situations such as overload, environmental factors, and physical wear and take precautions. It is the first example in the literature where the temperature of the transmission line is measured and mapped instantly by a robot. In the experiment, an artificially heated part of the line is detected and shown in a temperature map.