A newbie (not Newfie for those who know the difference) was asking if it is possible to determine or detect corrosion of an overhead transmission line porcelain insulator pin shank through infrared thermography.
Understanding where or why the corrosion starts helps to understand what tool to use to see the cause of the corrosion.
Corona causes insulator pin corrosion, corona produces nitric acid in the presence of moisture from the air, and sound, ultraviolet light, ozone, and may raise the temperature of the air locally (small ball) about 4 to 7 degrees F when the corona is really active. Corona starts and stops, dependent upon variables such as the voltage applied, atmospheric pressure, temperature, wind speed, ...
So if you want to find corrosion look for a visible indication, if you want to find the cause of the corrosion or damaged insulators use a corona camera and ultrasound, if you want to find NCI insulator damaged areas and conductor damage use corona and infrared cameras, or to do all of these inspections concurrently use a MultiCAM with ultrasound option.
The CoroCAM 504 and MultiCAM now have the UltraProbe 9000 option because, the airborne sound waves from corona typically travel in all directions (omni-directional), can be heard thru a cabinet wall (acoustic), and you can check the transformer fan motors bearings for lube (really).
The omni-directional sound waves are heard thru earphones worn by the camera operator, the camera operator upon hearing a corona or arcing sound knows to look and investigate something he may not see yet with his camera, upon locating the problem the camera operator uses one button to take a picture and store it to the camera, a second button to store an audio clip of the ultrasound and a verbal description of the pole/property/tower number and the problem.
The CoroCAM 504 has a daylight corona camera and a menu selected daylight-filter-removal from the optical path making it the most sensitive daylight and lowlight corona camera available on this planet! This is a great camera for all applications from substations thru hydro generators and into the laboratory or QA in-plant. Combined with ultrasound it is the Best Daylight Corona detection tool for those who have a good infrared camera.
The MultiCAM has a daylight corona overlaid onto long-wave infrared or color visible with the push of one button. The MultiCAM also has a Full Radiometric Long-Wave Infrared camera available with deliveries starting before August 15, 2008 and don't delay - order today. If your infrared camera is due for replacement and you need to add corona inspection then you need to look at the MultiCAM as a lowest ownership cost to "Get `er Done" and have all of the indications stored on one memory card for report preparation. Combined with ultrasound it is the Total Corona+Infrared+Visible+Ultrasound detection and recording tool for those who are ready to replace there infrared camera or who do aerial surveys. Time is money in the air and the MultiCAM gets you the info instantly.
Doing the job right takes less time when you have the right equipment and training to understand the relationship of the indications provided by the CoroCAM 504 or the MultiCAM with UltraProbe ultrasound option.