The influence of temperature on high and low voltage switchgear

The low-voltage electrical appliances in the mine switchgear are composed of fuses, AC contactors, residual current-operated protectors, capacitors, and meters. These low-voltage electrical appliances are designed and manufactured in accordance with the "Basic Standards for Low-Voltage Electrical Appliances", and their normal working conditions are specified accordingly: the upper limit of the ambient air temperature does not exceed 40. The average value of the ambient air temperature for 24 hours does not exceed 35, and the lower limit of the ambient air temperature is not less than -5 or -25. The switchgear modified by the rural power grid is operated outdoors. It not only generates high temperature due to direct sunlight, but also generates heat during operation. Therefore, in the high summer season, the temperature inside the switchgear box will reach 60 or more. The temperature greatly exceeds the specified ambient temperature of these electrical appliances, and then failures caused by overheating of electrical components in the switch cabinet will occur.