In the power transmission and distribution system of the factory, there are a large number of contacts, switches, bushing clamps and other electrical equipment, often due to poor contact, corrosion or internal abnormalities and other reasons, there are abnormal hot spots, which seriously affect the safety of power supply.

The use of thermal imager can accurately detect hot spots, eliminate hidden dangers in time, and ensure the safety of power supply. Take a look at the actual case of testing in a factory.

Practical cases of "general defects"

The temperature rise range of "general defects" is between 10 ℃ and 20 ℃. Compared with P1 and P2 joints under the same operating conditions, the temperature rise of this joint is certain, and only slight thermal image characteristics are detected by thermal imager. In this case, attention should be paid to check whether it is caused by excessive load current, and tracking should be strengthened to prevent the deepening of defects.

In addition, it should be noted that although the relative temperature difference is small, you should pay attention to check the load condition. If the load rate is low, it means that once the load rate increases, the temperature at the defect of the electrical connector of the equipment will rise sharply.

Practical cases of "serious defects"

"Serious defect", the temperature rise range of its hot spot is between 20 ~ 40 ℃, or the actual temperature is between 60 ~ 80 ℃, or the temperature difference between phases of the equipment is between 1.5 ~ 2.0 times, the thermal image characteristics are obvious, and the defect has caused serious thermal damage, which poses a serious threat to the operation of the equipment.

After the overload condition is confirmed, the thermal defects should be monitored for a long time to avoid further deterioration. If production conditions permit or necessary, it should be adjusted in time to avoid causing major economic losses.

Practical cases of "critical defects"

"Critical defect", the temperature rise of the hot spot exceeds 60 ℃, or the maximum temperature has exceeded the maximum allowable value of the material specified in the national standard gb763-90. The temperature of phase a of capacitor connector in the figure below is 99.2 ℃ higher than that of phase C, which is a "critical defect".

After careful examination, it is found that the aging of A-phase joint leads to poor contact and abnormal high temperature due to increased resistance. The thermal image of this kind of defect is very clear, which may cause sudden accidents at any time, so it should be out of operation immediately and overhauled thoroughly.