Detection of electrical faults with infrared thermography

One of the problems that concern most often the electricians is how to determine the conditions or the state of operation of electrical systems quickly, without physical contact with the components and without disconnecting the network system. In other words, how to identify and locate latent defects that would cause unpredictable catastrophic failures, such as poor contact caused by corrosion and oxidation, loosening or bad crimp lugs, overloading of cables and transformers, imbalance phase loads, etc. Most electrical faults are characterized by loss of energy and overheating of the components and eventually by the emission of a quantity of infrared energy which varies with the temperature of the components, according to Plank's law. The detection of this radiation by the infrared thermography technique it is possible to inspect hundreds of points and identify the presence or absence of electrical faults. IR thermography is a technique that converts the IR radiation into a visual image of the temperature difference shown by the surface of the components. The image obtained is a color map more or less clear showing "hot" zones and "cold" zones filmed surfaces. The inspection and comparison of the image obtained with the IR image of the reference corresponding normal operating state permit to locate the faults undetectable by the human eye. For example, a hot electrical interconnection may indicate poor contact requiring repair. The tool used in the IR thermography is a portable camera with a pyrometric sensor capable of measuring temperatures of - 40 degrees C to 1500 degrees C, with a resolution of about 0.1 degrees C. In this article, we present infrared thermography and its application for inspection and predictive / preventive maintenance of electrotechnical and electrical systems.