Thermal Imaging Detection Device Based on Infrared Photoelectric Sensor and Its Application in Fault Detection of Transformer Bushing Insulation

Abstract

Due to the unique advantages of infrared thermal imaging system compared with visible light, infrared photoelectric sensors can convert the perceived infrared light into electrical signals, which can help people to observe and analyze. Thermal imaging detection devices are developing towards miniaturization, low power consumption and high resolution. According to this requirement, the hardware design of thermal imaging detection system for infrared detection is carried out, and 640×512 uncooled infrared focal plane array is adopted. ADV7390 is selected as the video coding chip, and the low power consumption characteristics of this device are optimized. Selecting reference source+digital potentiometer+operational amplifier as analog bias scheme can make the output analog bias within a certain voltage range. The signal processing method of the detector is improved, that is, divide the voltage and form a differential signal with VREF, and then send it to the ADC chip. In the experiment, DC/DC switching power supply, LDO output voltage and ripple are tested. The results show that the measured voltage value is close to the standard voltage value, the signal voltage is basically around 2 V, and the signal voltage is lower than the signal range fluctuation, which is in line with expectations. It is used to detect transformer bushing insulation defects, and an infrared thermal imaging device is designed to capture bushing insulation defects. Combined with the feature point matching method, the infrared feature distribution of bushing insulation defects is obtained, and the infrared spectrum of the outside of transformer bushing can be obtained through continuous tracking to determine the abnormal temperature position.