The components in high voltage cabinet will form operating temperature when they are running, that is to say, the temperature rise is often said in professional terms. The over expenditure of temperature rise will cause great damage to the characteristics of insulating layer parts and the service life of machinery and equipment. Long term over expenditure of temperature rise will lead to the reduction of dielectric strength energy, which will lead to the safety accident of thermal breakdown of insulation layer. So, what is the key reason for the temperature rise of high-voltage cabinet? The manufacturer of metal material watch box summarized the following five points.

1. The statistical data measured in the experiment is generally carried out in the laboratory, with a delay time of not more than 8 hours, which does not have the effect of temperature rise and accumulation, and can not be equivalent to the long-term operation and continuous burning of machinery and equipment.

2. The swelling effect of different metal materials is different. The thermal expansion coefficient of metal material of steel bolt is much smaller than that of copper (chemical equation Cu) and aluminum (AL) bus, especially in the connection head of bolt type machinery and equipment, with the change of load current and temperature during operation, the expansion and closing level of aluminum or copper and iron will be different, resulting in stress relaxation, that is to say, the metal material will slowly plasticity under the effect of in-situ stress The whole process of deformation and stress relaxation is also closely related to the temperature at the interface.

3. The working pressure of tightening bolts at connection position (composition: brain and screw rod) is poor. Some installation or repair workers feel that the tighter the connecting bolt is, the better it is. When the working pressure of nut reaches a certain critical value, if the compressive strength of raw materials is poor, and then the poor working pressure is raised again, a part of the surface will be deformed and protruded, on the contrary, the total contact area will be reduced, the touch resistance will be extended, and then the actual effect of conductor touch will be damaged.

4. The conductivity of pure water of the conductor raw material does not meet the requirements, most of which is attributed to the lack of purity of the conductor raw material.

5. Other factors on the spot, such as improper installation, repair and processing technology, such as untimely, uneven and uneven surface treatment of the bus bar touching metal surface during the whole process of production, connection and installation, and no special electric power engineering grease is applied, resulting in the reasonable total area of touch falling, touch resistance expanding and burning.

Because the temperature in the high-voltage switchgear is too high, which leads to the thermal breakdown safety accident of insulation parts and the damage of the service life of the high-voltage switchgear machinery and equipment, therefore, it is necessary to pay attention to the change of temperature in the high-voltage switch cabinet during installation and operation