Field studies of dynamic thermal rating methods for overhead lines

Dynamic thermal circuit rating (DTCR) is a method of monitoring and dynamically uprating existing transmission circuits. This paper describes the results from a series of field tests of the overhead line module of the software at a number of unique field test sites. This initial analysis of field data, which is essential to establishing the functionality, accuracy, and reliability of the method, addresses questions that are of interest to anyone attempting to evaluate or implement dynamic line ratings. Among the key questions considered in the paper are: (1) are real time line monitors (sag, tension, temperature) needed? (2) how many monitoring locations are necessary to rate an overhead line? (3) how are temperature and sag-tension related at high conductor temperature? and (4) which monitoring method works best under normal and emergency line load levels.