Do you know about oil-immersed transformers?

Component composition:

1. Core: This is the magnetic part of The Transformer, composed of silicon steel sheets stacked together. It has two structures: core type and shell type. Currently, the widely used core type is composed of iron columns and iron yokes. The core has cooling oil channels inside, facilitating the circulation of transformer oil for heat dissipation.
2. Windings: Also known as coils, they are the conductive circuits of the transformer, made by winding copper or aluminum wires into multiple layers of cylindrical shapes. The primary and secondary windings are concentrically placed on the iron core column, with the low-voltage winding inside and the high-voltage winding outside. There is insulating material between the windings.
3. Oil tank: This is the outer shell of the transformer, used to hold oil and install other components. The oil tank of large-capacity transformers usually has heat dissipation plates or heat dissipation tubes on the outside.
4. Gas relay: Also called a gas relay, it is installed in the middle of the connection between the oil tank and the oil reservoir, serving as the main protection device for internal faults of the transformer.
5. Insulating bushing: Located on the top cover of the transformer oil tank, it is generally made of porcelain insulating bushing, maintaining good insulation between the high and low voltage winding leads and the oil tank, and fixing the leads.
6. Voltage regulating device: Set to ensure the stability of the secondary voltage of the transformer, it is divided into on-load voltage regulating device and off-load voltage regulating device.

Working principle: Based on the principle of electromagnetic induction, when the high-voltage winding is energized, a varying electromagnetic field is formed in the iron core, thereby inducing an electric potential in the low-voltage winding, achieving the transformation and transmission of electrical energy.

Cooling method: Usually, three cooling methods are adopted, namely oil-immersed self-cooling type, oil-immersed air-cooling type and forced oil circulation type. The oil-cooled self-cooling type relies on the natural convection of oil to dissipate heat. The oil-immersed air-cooled type is based on the oil-immersed self-cooling type. In addition, fans are installed to blow air into the oil tank and oil pipes to enhance the heat dissipation effect. The forced oil circulation process involves using an oil pump to draw the hot oil from the transformer and cool it outside the transformer before reintroducing it back into the transformer.

Advantages:
1. Excellent heat dissipation performance: The specific heat capacity of insulating oil is high, and its thermal conductivity is excellent. It can effectively transfer the heat from the windings and the core, ensuring stable equipment temperature.
2. Stable insulation performance: The dielectric breakdown voltage of insulating oil is high, and it can repair local discharge damage and delay insulation aging. The aging speed of its insulation system is slow, and the design life can reach 30 years.
Outstanding overload capacity: Due to the thermal capacity characteristic of the oil, it has a strong short-term overload capacity, which can flexibly cope with fluctuations in grid load or sudden peak demand.
3. Strong environmental adaptability: The oil tank has a high protection level, capable of withstanding outdoor, humid, and dusty environments, and can operate in a wide temperature range of -30℃ to 40℃.
4. Application fields:Widely used in Substations and power stations in power transmission and distribution systems, industrial sites such as factories, mines, and metallurgy, construction fields such as buildings, shopping malls, and hotels, as well as railways, subways, and power plants.