Dry Transformers Normal Temperature
The normal temperature of the dry transformers does not exceed 145°C, and it can be used normally. However, if the temperature of the dry-type transformer is too high, it will cause the insulation to age slowly. The lower the temperature of the transformer, the better.
In fact, because the actual ambient temperature of electricity consumption changes in the four seasons of each year, the summer temperature may exceed the temperature standard, and the winter temperature is usually lower than the temperature standard. But as long as the fluctuation average line of winding temperature in four seasons of each year does not exceed 145 ℃, its aging speed can also be within the normal and acceptable range.
The temperature rise of the dry transformers does not exceed 70°C. If the temperature is too high, the aging of the internal insulation parts of the equipment will be accelerated. If it is necessary to adjust the ambient temperature during transformer operation, it can be controlled below 50°C. Generally, the factory setting is 90°C to start the fan for heat dissipation, 120°C to start the high temperature alarm, and 160°C to trip the ultra-high temperature. The higher the temperature during operation, the greater the resistance value will be, the heat will increase continuously, and the efficiency will decrease significantly. This is a problem of positive feedback. If it is an F-class insulation system, the normal operation is controlled at 40-60°C more appropriate. Under normal circumstances, the temperature of a dry transformers working under normal conditions reaches 98°C, which is considered relatively high. At that point no more load can be added. Low-voltage equipment generally requires that the temperature rise not exceed 65°C. Excessive temperature will accelerate the aging of the insulation parts of the equipment and reduce its service life.
For the coils of dry transformers, when Class A insulating materials should be used, the maximum operating temperature should be less than 65K at 108°C; if Class E insulating materials are used, the maximum operating temperature should be at 121°C. The maximum temperature rise should be less than 78K; if class B insulating material is used, the maximum operating temperature should be less than 85K at 131°C; if class F insulating material is used, the maximum operating temperature is 156°C, The maximum temperature rise should be less than 105K; if class H insulating material is used, the maximum operating temperature should be less than 125K at 181°C; if class C insulating material is used, the maximum operating temperature should be at 221°C, The maximum temperature rise should be less than 155K.
