Thermal imagers can measure the temperature of electrical equipment such switchboards, transformers, generators, etc. and analyze the situation on the spot. But can the cause be determined solely by a thermal imager? How can thermal imagers actually be useful?
1. Use and drawbacks of infrared thermal imaging
In order to obtain an infrared thermal image that corresponds to the distribution field, an infrared thermal imager uses an infrared detector and an optical imaging objective to collect the infrared radiation energy distribution pattern of the measured target and reflect it on the photosensitive element of the infrared detector. In plain English, an infrared thermal imager transforms an object's invisible infrared energy into a visible thermal image. The thermal image's various colors on top correspond to the detected object's various temperatures.
Thermal imaging cameras can measure the surface temperature of electrical equipment such switchboards, switch boxes, transformers, breakers, contactors, fuses, cables, generators, winding machinery, oil pillows, UPSs, etc. in the electrical field. The electrical equipment will be harmed or even destroyed if the temperature is too high, so the temperature sensing can serve some protection function. The thermal imager can only take photographs and record changes in the equipment's temperature. The pre-judgment function cannot precisely pinpoint the issues on the site and cannot examine the power quality of the site, and the temperature detection merely serves as a protection function.
2. Electrical reasons for temperature rise
The continuous increase in temperature during the working process of electrical equipment will damage the equipment, and even lead to fire. Harmonics are the main culprit in causing the temperature increase.
Harmonics reduce the efficiency of the production, transmission and utilization of electrical energy, overheat electrical equipment, generate vibration and noise, and age insulation, shorten its service life, and even fail or burn out. Harmonics can cause local parallel resonance or series resonance in the power system, amplify the harmonic content, and cause capacitors and other equipment to burn. Harmonics can also cause malfunction of relay protection and automatic devices, causing confusion in electric energy measurement. For the outside of the power system, harmonics can cause serious interference to communication equipment and electronic equipment.
