Detailed explanation of the transformer cooling system (previous)
An electrical transformer cooling system consists of two components: an internal cooling system that ensures condensation and core heat access to the surrounding medium. An external cooling system ensures that heat flows from the medium to the transformer. Transformer capacity varies with size, medium and cycle. Transformers are cooled in different ways.
1,Oil-immersed self-cooling
Oil-immersed self-cooling cooling system without special cooling equipment, oil in the transformer natural circulation, iron core and windings issued by the heat on the oil convection effect to the tank wall or radiator. According to the size of the transformer capacity, and can be divided into three different structures:
1.1, smooth type box wall. Transformer with very small capacity adopts this structure, the box shell is welded with steel plate, the box wall is completely smooth;
1.2, heat dissipation rib type box wall. In the smooth box wall welding some heat dissipation rib, expand the area of contact with the air, suitable for slightly larger capacity transformer;
1.3, heat pipe or radiator type cooling. Larger capacity transformer, in order to increase the cooling surface of the tank, it is installed outside the tank with a number of radiators, radiators are a set of cooling tubes with upper and lower joint box, radiators are connected to the tank through the flange, is a detachable part.
2,Oil-immersed air-cooled
Oil-immersed air-cooled cooling system, also known as oil natural circulation, forced air-cooled cooling system. It is in the transformer oil tank next to each radiator installation of a to several fans, the natural convection of air to change the role of forced convection, in order to enhance the radiator's ability to dissipate heat. It is compared with the self-cooling system, the cooling effect can be increased by 150% to 200%, equivalent to the transformer output capacity increased by 20% to 40%.
When the load is small, the fan can be stopped to make the transformer run in self-cooling mode, and when the load exceeds a certain value, such as 70% of the rated load, the fan can be put into operation automatically. This type of cooling is widely used in medium capacity transformers above 10000 kva.