Non-contact temperature measurement method for dynamic rating of overhead power lines

Abstract

The increase in energy efficiency of power systems and the development of smart grids are strongly based on new and more accurate ways of monitoring. In overhead power line systems, the focus is on monitoring weather conditions and the main line parameters, such as the current and temperature of the conductor. Current and temperature are linked by the Joule heating effect and ampacity, which is the maximum amount of electrical current a conductor can continuously carry before sustaining deterioration given the dynamic environmental conditions. Conductor temperature is also related to another critical parameter for overhead power lines: their maximum allowable sag. These two parameters, ampacity and sag, give an idea of the importance of conductor temperature dynamic monitoring. There are several contact temperature methods on the market; however, they are expensive and challenging to implement owing to the complexity of electronic devices working in a high voltage environment related to the maintenance and life span of the instrumentation. This paper presents a novel method to estimate the temperature of overhead power lines using a non-contact infrared system. From the comparison between contact and non-contact temperature measurement methods a correction function was obtained to infer the temperature of the conductor from the infrared measurements. This option has several advantages in comparison with the current methods as it is a cheap and passive system that foregoes the need to attach electronic components to the power line, thus simplifying the maintenance and improving the safety of the operations.