There are strict restrictions on the temperature of contact points such as electrical equipment. For example, copper joints and silver plated cables need to be connected at a temperature 45 ℃ higher than the ambient temperature, and the actual temperature is controlled at 85 ℃. Prolonged exposure to high temperatures at the contact points can lead to insulation degradation and even electrical fires.

Due to the long-term high level operation of electrical equipment, it is easy to cause equipment aging. Some equipment is exposed to air for a long time, and due to the effects of high temperature, humidity, gas, dust, etc., it can cause scaling or corrosion on the surface of the equipment, resulting in poor contact and heat generation. External forces can also easily cause damage to equipment components, such as poor contact of equipment joints, heat generated by bolts and washers not being tightened or being too tight. The internal operation of the equipment, such as current overload or internal component failure, can cause excessive overheating and lead to equipment failure.

During long-term operation of AC high-voltage electrical equipment, if the surface temperature exceeds 50 ℃ or the relative temperature difference exceeds 20 ℃, there is a thermal hazard. Generally, timely detection and adjustment will not result in adverse consequences.

When the surface temperature exceeds 75 ℃ or the relative temperature difference exceeds 50 ℃, there is a serious thermal defect that requires timely cooling treatment.

When the surface temperature exceeds 90 ℃ or the relative temperature difference exceeds 50 ℃, it is considered a critical thermal defect, and the electrical equipment is overloaded. It is necessary to quickly stop production in a short period of time to minimize losses. If not dealt with in a timely and effective manner, serious electrical fires and safety accidents will occur.

In many scenarios, maintenance personnel are unable to visually capture the fault points of the equipment through the naked eye. Traditional five senses (visual, auditory, olfactory, gustatory, and tactile) methods are difficult to directly or indirectly grasp the temperature changes and operating status of the equipment. They are prone to overlooking temperature anomaly point detection, resulting in unplanned fault maintenance, misjudgment, and ultimately leading to maintenance decision-making errors, resulting in secondary damage to the equipment. In severe cases, It can also easily lead to economic losses caused by major maintenance and inspection errors.

Infrared thermal imaging technology mainly detects the infrared radiation of a target object, and uses signal processing, photoelectric conversion and other methods to convert the temperature distribution image of the target object into a visible image.

The vast majority of operations and maintenance of electrical equipment are difficult for the human eye to recognize, and with the assistance of infrared thermal imaging devices, temperature levels can be distinguished by real-time image colors. Power maintenance engineers only need to determine the color depth of the imaging images to make a judgment.

It should be noted that in addition to common infrared detection methods, there is also a more mature ultraviolet detection technology. Infrared and ultraviolet are used to diagnose and evaluate the operating status of charged equipment from two aspects: temperature and corona. Infrared utilizes the temperature characteristics of the device surface to determine the heating fault of the device; Ultraviolet utilizes the ultraviolet radiation generated by ionized air discharge around charged equipment to determine partial discharge faults in the equipment. These two methods complement each other and cannot replace each other. The weak heat caused by corona discharge defects cannot be effectively detected by infrared, and the temperature anomaly defects also exceed the range of ultraviolet detection.

The transformer casing is abnormally overheated, with eddy current overheating, poor connections at the upper and lower ends of the high and low voltage bushings, and defects such as oil shortage (low oil level) in the filling bushing.

Mainly due to surface fouling of ceramic columns, cracks in ceramic columns, deterioration of insulation diagrams, and poor isolation contact.

Various types of capacitors have overheating, poor oil insulation of coupling capacitors, and defects such as low oil level.

Overheating faults of the guide body caused by poor contact, moisture inside the insulation porcelain sleeve, poor contact between the dynamic and static contacts, lack of oil, poor contact between the intermediate contacts, and poor contact between the static contact base.