Transformer runtime core loss and winding loss and the additional loss, etc. The loss on the one hand, reduce the efficiency of transformer, on the other hand into heat, make the temperature rise of transformer on part. Due to temperature difference exists between the transformer parts with the surrounding medium, just heat to the surrounding media. When the heat generated by the equals the heat transformer temperature to reach a stable value of each part. When the transformer in a certain part of the difference between the temperature and the cooling medium temperature around that part of the temperature rise (The highest temperature regulation in our country environment is 40 ℃. To stabilize transformer temperature rise time, due to the transformer capacity size and cooling methods vary. Small capacity of oil-immersed and dry type transformer, run after 10 h would be able to reach the r think stable temperature rise. Large transformer should pass the 24 h to reach stable temperature rise. Usually oil-immersed transformer cooling process is as follows: first of all, by conduction effect will winding and iron core internal heat to the surface. Then heat by natural convection of transformer oil is constantly to oil tank wall and pipe wall, and then through the oil tank wall and wall conduction effect of the heat from their inner surface to the outer surface, and finally by radiation and convection heat into the surrounding air. The rise of temperature of the transformer directly affects its load capacity and service life, in order to guarantee the safe operation of the transformer. Measures must be taken to reduce the temperature rise of transformer.
