What is the relationship between dry-type transformer temperature and service life?

GNEE Steel 3 phase dry type transformer

Temperature is a concept of the external environment. The operating environment of dry-type transformers is also affected and restricted by temperature. Without good temperature, it is impossible for dry-type transformers to operate well. For the temperature of dry-type transformers, not only It affects the operation of dry-type transformers and also affects the service life of dry-type transformers. Therefore, it is necessary to correctly grasp the temperature of dry-type transformers and operate dry-type transformers at appropriate temperatures. This will help improve the performance of dry-type transformers. service life. So what is the relationship between the two?

dry type power transformer

Most power dry-type transformers use oil-paper insulation, that is, Class A insulation. For dry-type transformers with Class A insulation, in normal operation, when the ambient air temperature is 40°C, the operating temperature of the dry-type transformer windings is 105°C. Practice and research show that if the winding can continuously maintain a temperature of 95°C, the dry-type transformer can be guaranteed to have a service life of 20 years. According to the relationship between temperature and life, a so-called 8°C rule can also be derived: Based on the life at the above temperature, for every 8°C increase in winding temperature, the service life of the dry-type transformer will be shortened by 1/2. When the insulation working temperature of dry-type transformer is 95℃, the service life is 20 years. The insulation working temperature is 105℃ and the service life is 7 years. When the insulation working temperature is 120℃, the service life is 2 years. Under the premise that the voltage is basically constant, the insulation temperature inside the dry-type transformer is mainly related to the load current. That is, the larger the load current, the higher the insulation temperature. On the contrary, the smaller the load current, the lower the insulation temperature. The temperature of the dry-type transformer is closely related to the service life of the dry-type transformer, so the temperature of the dry-type transformer must be correctly grasped.