Can 3 phase dry type transformer be overloaded?

1. Generally, overload operation of transformer is prohibited. In special circumstances, it can be overloaded for a short time. How long can they be overloaded? Looking at the product information of the transformer manufacturer, it clearly shows that the transformer performance of different manufacturers is different. 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 3 phase dry type transformer has a certain overload capacity, and its purpose is to be as small or no load as possible in the event of a fault, not for normal use. For example, if two parallel transformers with 60% load ratio trip, all the load provided by both transformers will be transferred to the other transformer, the remaining transformers will be overloaded by a factor of 1.2, and then the load on the transformers will be reduced in the shortest possible time to normal levels.

3. The most economical operating load rate of the transformer is about 670%. The load is too low, the transformer capacity is wasted, and the reactive power is wasted. Overload operation can affect the insulation life of the transformer.

4. That is to say, the normal operation of the 3 phase dry type transformer can be used for 10 years. If the transformer is frequently overloaded, it may age in advance and be scrapped after 3 years. Therefore, it is necessary to comprehensively consider the cost of overload or transformer conversion. From practical experience, the cost of transformer retrofit is not an order of magnitude, but the cost saved by overloading. It is recommended to strictly control the transformer not to overload. No matter who owns the property rights of the transformer, it should compensate the transformer damaged by overload.

5. Under the premise of ensuring safety, no one can guarantee the safety of the transformer, which is often overloaded. The problem of insulation decline caused by overload is a process from quantitative change to qualitative change. Today, after some time, the measured temperature is still normal. Even without overloading and normal operation tomorrow, the temperature will suddenly rise a few times. A transformer that is overloaded for a long time may catch fire or even explode at any time, which is uncontrollable. 3 phase dry type transformer