The impact of high temperature weather on explosion-proof electrical systems

Recently, there have been widespread occurrences of high temperatures across the country, with many regions issuing red alerts for high temperatures, with the highest temperature reaching 40 degrees Celsius. In such hot weather, it is extremely important for enterprises and institutions to ensure the safe operation of electrical equipment, take preventive measures for the safe operation of electrical equipment in summer, establish a regular inspection system for electrical equipment, and conduct preventive tests on relevant high-voltage equipment and safety tools.

Electrical equipment generates heat during operation, so it has certain requirements for environmental temperature and heat dissipation. If the environmental temperature is too high, it can cause electrical equipment to exceed the temperature limit and malfunction. Regarding the impact of temperature on electrical equipment, the parts and materials used in the product may experience softening, reduced efficiency, changes in characteristics, potential damage, oxidation, and other phenomena at high temperatures. The main impacts of high temperature environment on equipment are:

1. Softening or melting of fillers and sealing strips;

2. Lubricant viscosity decreases, volatilization accelerates, and lubrication effect decreases;

3. The stability of electronic circuits decreases and insulation is damaged;

4. Accelerate the aging of polymer materials and insulation materials, including oxidation, cracking, chemical reactions, etc;

5. The expansion of materials causes an increase in mechanical stress or wear.

In detail, there are mainly the following aspects:

01. Impact on metal materials

The temperature rises and the metal material softens. The mechanical strength will significantly decrease. For example, when copper metal materials work at temperatures exceeding 200 ℃ for a long time, their mechanical strength significantly decreases; When the short-term working temperature exceeds 300 ℃, the mechanical strength also decreases significantly. The mechanical strength of aluminum metal materials is also closely related to temperature. Generally, the long-term working temperature of aluminum should not exceed 90 ℃, and the short-term working temperature should not exceed 120 ℃.

02High indoor temperatures can cause rapid insulation aging of electrical equipment, resulting in a decrease in its service life and rated current. Due to internal losses during the operation of electrical equipment, the equipment has a certain temperature. If the indoor environment temperature is too high or the air flow is poor, the heat of the equipment cannot be dissipated in time, which will cause the equipment to trip due to overheating and even burn out the equipment. Electronic products inside the distribution box, such as residual current operated protectors and electronic meters, can affect the stability of protector performance, reliability of operation, and accuracy of measurement when operating at high temperatures. Long term operation at high temperatures can cause insulation aging of electrical equipment, leading to a decrease in its service life.

03. Impact on electronic components

High temperature is the enemy of many electronic components. For example, high temperature can cause thermal breakdown of semiconductor components. As the temperature increases, the degree of electronic activation intensifies, causing the originally non-conductive semiconductor layer to conduct; High temperature deteriorates the performance of electronic components, such as an increase in reverse conduction current and a decrease in amplification factor at higher temperatures.

04. Impact on insulation materials

If the temperature is too high, organic insulation materials will become brittle and aged, with decreased insulation performance and even breakdown, and the service life of the material will be shortened. For example, within a certain temperature range, for every 8-10 ℃ increase, the service life of insulation materials is shortened by about 50%. Therefore, it has a significant impact on motor equipment.

Excessive temperature also has a significant impact on the insulation performance of inorganic insulation materials. For example, the breakdown strength of electric porcelain is about 250kv/mm at temperatures below 80 ℃. At 100 ℃, its breakdown strength is about 100kv/mm.

05. Impact on Electrical Contact

Poor electrical contact is an important cause of many electrical equipment failures, and the temperature of the electrical contact part has a significant impact on the integrity of the electrical contact. If the temperature is too high, the surface of the conductor at the electrical contact point will oxidize violently, and the contact resistance will significantly increase, causing the temperature of the conductor and its accessories (components) to rise, and even possibly causing the contact to melt. The contact pressed by the spring, after the temperature rises, the spring pressure decreases, the stability of the electrical contact is worse, and it is more likely to cause electrical faults.

Install thermal protection devices and overcurrent protection devices to stop in a timely manner when overload occurs.