Experimental Verification of a Real-Time Program for the Determination of Temperature and SAG of Overhead Lines

An outdoor test facility was used to experimentally verify real-time overhead conductor ampacity and sag programs. The facility consists of a 213m span of 26/7 336 kcmil ACSR conductor completely instrumented ented with 13 thermocouples as well as a sag and tension device. A weather station mounted near mid-span monitors all pertinent weather conditions. The measured conductor tempetatures fluctuated significantly antly along the length of the test span. Spanwise variations in the measured instantaneous temperatures were frequently in excess of 100C for a wide variety of conductor currents and weather conditions. The conductor temperatures predicted by the real-time ampacity program ram were within°C100C of the average measured conductor temperatures for all tests. Measured conductor sags were within 5 percent of values predicted by a real-time sag program. The results of the experimental project show that accurate predictions of real-time conductor temperatures and sags can be achieved by knowing the conductor current, wind speed, wind direction and the ambient air temperature. Therefore, computer programs are capable of predicting conductor temperatures and sags with a minimum amount of weather data provided by a simple and inexpensive weather station. Instrumentation ation placed on the conductor is not necessary for execution of the ampacity and sag programs.