The operation of oil-immersed transformers is based on the principle of electromagnetic induction. When an alternating current passes through the primary winding, an alternating magnetic flux is generated in the core. Due to the excellent magnetic permeability of the core, almost all the magnetic flux is concentrated inside the core, forming a closed magnetic circuit. This alternating magnetic flux passes through both the primary winding and the secondary winding simultaneously. According to the law of electromagnetic induction, an electromotive force proportional to the voltage of the primary winding will be induced in the secondary winding. By rationally designing the turns ratio of the primary winding and the secondary winding, the voltage can be increased or decreased to meet the Изисквания за напрежение на различни потребители .
During this energy transfer process, energy losses are inevitable, mainly manifested as hysteresis losses and eddy current losses in the core, as well as resistance losses in the windings. These losses will be converted into heat, causing the temperature of the transformer to rise. Transformer oil plays a crucial role in this process. Transformer oil has excellent insulating properties and can effectively isolate the conductive parts between the windings and the core, as well as between the windings themselves, preventing short-circuit faults. Meanwhile, transformer oil also has a high specific heat capacity and good fluidity, which can absorb the heat generated by the windings and cores, and transfer the heat to the tank wall through natural convection or forced circulation, and then dissipate it into the surrounding environment, thus ensuring that the transformer operates within нормалния температурен диапазон .
