Oil-immersed transformers are core equipment in power systems, enabling voltage transformation and energy transfer. Their working principle is based on electromagnetic induction, utilizing insulating oil for insulation and heat dissipation, ensuring stable and efficient system operation.
1. Electromagnetic Induction as the Foundation, High-Efficiency Energy Conversion
Oil-immersed transformers rely on electromagnetic induction for energy transfer. Primary and secondary windings are wound on a closed iron core. When an AC power source is applied to the primary side, an alternating magnetic flux is generated, inducing an electromotive force on the secondary side, thus achieving voltage transformation. The voltage ratio is strictly equal to the turns ratio, i.e., E₁/E₂ = N₁/N₂. This is the core principle behind the precise voltage transformation achieved by oil-immersed transformers. The iron core is made of cold-rolled silicon steel sheets, effectively reducing hysteresis and eddy current losses, and improving energy efficiency.
2. Dual Functions of Insulation and Cooling, Oil Circulation Ensures Safety
Insulating oil in oil-immersed transformers performs a dual function of insulation and cooling. As an insulating medium, it effectively isolates the windings, core, and grounding components, preventing internal short circuits. As a cooling medium, it transfers the heat generated during operation to the tank wall through convection circulation, and then dissipates it through radiators or cooling fans, maintaining stable operation of the equipment at a safe temperature.
3. Precise Coordination of Structural Components for Stable Protection System Operation
An oil-immersed transformer is composed of the transformer body, tank, cooling system, and protection devices working together. The transformer body includes the core and windings, which are often arranged concentrically or overlapping to optimize electromagnetic performance. The tank's sealed design accommodates the transformer body and insulating oil; large transformers are also equipped with cooling devices to enhance thermal management. Protection devices such as gas relays monitor fault gases and trigger alarms, while the oil conservator regulates oil level changes and prevents oxidation, collectively ensuring the long-term reliable operation of the oil-immersed transformer.
