EVALUATION OF THERMAL RATING METHODS BASED ON THE TRANSMISSION LINE MODEL

Electric power consumption has been growing continuously, especially in the last years. Therefore, implementation of new advanced technologies such as the overhead line thermal monitoring is topical for improvement of the existing transmission line network in order to increase its throughput capacity and reliability of power supply. In general, the real-time thermal monitoring systems are designed based on the existing methods using the limiting conditions for ampacity determination of high-voltage overhead lines. The paper considers commonly used methods for thermal rating estimation which include computation of the conductor temperature and of the conductor sag. Comparative analysis was performed for the measured and calculated steady-state conductor temperatures and line sagging, based on which the thermal rating methods were tested. The experimental measurements were conducted for three cases using special monitoring equipment. The study has been carried out based on the existing line model of the Latvian transmission grid.