Influence of Atmospheric Attenuation: The infrared radiation energy on the surface of the electrical equipment under test is transmitted through the atmosphere to the infrared detection instrument, which is affected by the absorption attenuation of gas molecules such as water vapor, carbon dioxide, and carbon monoxide in the atmospheric composition, as well as the scattering attenuation of suspended particles in the air. The attenuation of equipment radiation energy transmission increases with the distance between the detection instrument and the equipment under test, reducing the transmittance of the equipment's radiation. Therefore, the attenuation increases with distance. This reduces the radiation contrast between the fault area and the normal area of the equipment under test, and because the infrared instrument receives less target energy, the temperature displayed by the instrument is lower than the actual temperature at the fault point, potentially leading to missed detection or misdiagnosis, especially when detecting equipment faults with low temperature rise. As the detection distance increases, the influence of the atmospheric composition becomes more significant. To obtain accurate target temperature, it is necessary to conduct detection during periods when the atmospheric environment is relatively dry and clean; shorten the detection distance as much as possible without compromising safety, and apply reasonable distance correction to the temperature measurement results to obtain the actual temperature value.
Influence of Meteorological Conditions: Adverse weather conditions (rain, snow, fog, strong winds, etc.) can have a negative impact on equipment temperature detection, often giving false fault indications. To reduce the influence of meteorological conditions, detection should be carried out as much as possible on nights without rain, fog, wind, and with relatively stable ambient temperature.
Influence of Environment and Background Radiation: During outdoor infrared detection of electrical equipment, the infrared radiation received by the detection instrument includes not only the radiation emitted by the corresponding part of the equipment under test but also reflections from other parts of the equipment and the background, as well as direct solar radiation. These radiations interfere with the temperature of the part to be measured, causing errors in fault detection. To reduce the influence of environment and background radiation, when conducting on-site infrared detection of outdoor electrical equipment, it is advisable to choose cloudy days or times without sunlight in the evening. This prevents the influence of direct, reflected, and scattered solar radiation; for indoor equipment, turning off lighting and avoiding other radiation influences can be adopted. For surfaces with high reflectivity, appropriate measures should be taken to reduce the influence of solar radiation and radiation from surrounding high-temperature objects, or change the detection angle to find an angle that avoids reflection. To reduce the influence of solar radiation and radiation from high-temperature backgrounds, appropriate shielding measures should be taken during detection, or appropriate infrared filters should be installed on the infrared measuring instrument to filter out solar and other background radiation. Select an instrument with suitable parameters and detection distance so that the part of the equipment under test is within the instrument's field of view, thereby reducing background radiation interference.
