Uncertainty analysis applied to electrical components diagnosis by infrared thermography

摘要

This work presents a discussion on the use of infrared thermography to detect degradation of electrical components, highlighting the importance of uncertainty analysis into decision making process. Some technical standards recommend to use temperature differences between similar components as an integrity indicative (a comparative approach). Temperature measurement from infrared cameras is dependent of target surface emissivity and environmental conditions, which impact the measurement accuracy and lead comparative approaches to inconclusive results. We make laboratory experiments under controlled conditions to demonstrate how emissivity affects the temperature uncertainty. We also performed a thermographic inspection using NETA MTS-2011 for an electrical substation connector and discuss the influence that temperature uncertainty has on recommended actions suggested by this standard. Uncertainty was determined using the Guide to the Expression of Uncertainty in Measurement (GUM) and the Monte Carlo Method (MCM). We concluded that uncertainty measurement analysis of thermographic inspections is a crucial step on preventive maintenance of electrical components. (C) 2018 Elsevier Ltd. All rights reserved.