An experimental evaluation of a thermal line uprating by conductor temperature and weather monitoring

Conductor temperature monitors were installed on a four-mile-long section of 115 kV transmission line and served as the basis for the dynamic thermal rating of the line during June and December of 1985. A method of detecting temperature monitor measuring errors is described, and a method to correct the thermal rating of the line is given. Of the four spans containing temperature monitors, no one span was consistently the hottest, but for each month, one span was hottest more than half the time. By accounting for variations in span orientation along the test line section, it was found that the weather data from a single weather station as far as 20 miles away could be used to predict the statistical distribution of thermal ratings for the test line. The dynamic thermal rating of the test line was above the line´s static rating some 80% to 90% of the time, being 15% to 30% higher 50% of the time. The correlation of peak contingency loading and peak dynamic thermal rating is identified as a major factor in evaluating the use of dynamic rating methods in line uprating