Industry News

What is the max working temperature of dry-type transformer? What's the lifespan?

2020-08-21

The dry-type transformer can be used normally if the normal temperature does not exceed 145℃. However, if the temperature of a dry-type transformer is too high, the insulation will gradually age, so the lower the temperature of the transformer, the longer lifespan will be. Under normal use, dry-type transformers can be used for about 20 years.


In fact, since the actual electrical environment temperature changes in the four seasons of the year, the temperature in summer may exceed its temperature standard, and the temperature in winter is usually lower than the temperature standard. However, as long as the average line of the winding temperature fluctuations in the four seasons of each year does not exceed 145°C, the aging speed can also be within the normal acceptable range.

The temperature rise of a dry-type transformer should not exceed 70°C, because too high of its temperature will accelerate the aging of the internal insulation of the transformer. Therefore, it is necessary to adjust the ambient temperature of the transformer during operation, and it is best to control it below 50°C. In order to cool the transformer, the transformer produced by ABOT Power will be equipped with two fans. When the transformer starts to work, the fan will run to cool the transformer.



The higher the temperature of the transformer during operation, the greater its resistance value will be, the heat generation will continue to increase, the efficiency will be significantly reduced, this is a problem of positive feedback. If it is a Class F insulation system, it is more appropriate to control the normal operation at 40℃~60℃. If the temperature of a dry-type transformer that works under normal conditions reaches 98°C, then it is already a relatively high value, so the load should not be increased anymore. Low-voltage equipment generally requires the temperature rise not to exceed 65°C. Too high temperature will accelerate the aging of the insulation parts of the equipment and reduce its lifespan




For dry-type transformer coils, when Class A insulation materials should be used, the maximum operating temperature should be less than 65K when the maximum operating temperature is 108°C; when Class E insulation materials are used, the maximum operating temperature is 121°C. The maximum temperature rise should be less than 78K; if class B insulation material is used, its maximum operating temperature is 131℃, and the highest temperature rise should be less than 85K; if class F insulation material is used, its maximum operating temperature is 156℃, The maximum temperature rise should be less than 105K; if class H insulating material is used, its maximum operating temperature is 181℃, and the highest temperature rise should be less than 125K; if class C insulating material is used, its maximum operating temperature is 221℃, The maximum temperature rise should be less than 155K.




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