Can dry-type transformers be overloaded?

1. Generally, overload operation of transformers is prohibited. In case of special circumstances, it can be overloaded for a short time. How much time can they be overloaded? Look at the product information of transformer manufacturers, which clearly explains that transformers from different manufacturers have different performance. The general requirements are 1.2 times/60 minutes, 1.3 times/45 minutes, 1.4 times/32 minutes, 1.5 times/18 minutes, and 1.6 times/5 minutes.
2. The transformer has a certain overload capacity, the purpose of which is to be as small or no load as possible in the event of a fault and is not used for normal use. For example, if two parallel transformers with a 60% load rate trip, all the loads supplied by the two transformers will be transferred to the other transformer, the remaining transformers will be overloaded by 1.2 times, and then the load on the transformers will be reduced to normal levels in the shortest possible time.
3. The most economical operating load ratio of transformers is about 670%. The load is too low, wasting transformer capacity and wasting reactive power. Overload operation can affect the insulation life of the transformer.
4. That is to say, the transformer with normal operation can be used for 10 years. If the transformer is often overloaded, it is possible to age prematurely and be scrapped after 3 years. Therefore, it is necessary to consider the cost of overload or transformer conversion. From practical experience, the cost of transformer retrofit is not an order of magnitude, but a cost saved by overload. It is recommended to strictly control the transformer overload. Regardless of who owns the transformer, the transformer damaged by overload shall be compensated.
5. Under the premise of ensuring safety, no one can guarantee the safety of the transformer, which is often overloaded. The problem of insulation degradation caused by overload is the process of quantitative change to qualitative change. Today, after some time, the measured temperature is still normal. Even if the temperature is not overloaded and normal operation tomorrow, the temperature will suddenly rise several times. Transformers that are overloaded for a long time can catch fire or even explode at any time, which is uncontrollable.