Evaluation of overhead line and joint performance with high-definition thermography

The advantage of using computational methods to evaluate the overhead-line temperature in conjunction with high-definition thermography is analysed. A high-current-carrying transmission line served as a test site to monitor the temperature of the conductor and an overheated joint. A computational method is used to assess the conductor temperature from the operating current, the wind speed and direction, and the outdoor temperature. The technique involves determining the difference between the temperature evaluated from simulations and the actual measured temperature. Once this difference is known, the operating parameters on the thermographic system are adjusted to get a valid temperature on the conductor within a certain probability factor. On the basis of these results, an attempt is made to evaluate the joint temperature from thermographic information on the conductor next to the joint. Plausible explanations for the observed differences and difficulties are discussed