Features of Oil Immersed Transformer
- ZHONGSHAO ‘s 10kV oil immersed distribution transformers are widely applicable in power distribution networks and industrial/mining enterprise power supply systems.
- We offer both fully enclosed and oil storage types of oil immersed transformers.
- Our 35kV three phase oil immersed distribution transformers use premium C.R.G.0. type cores with high quality oxygen free copper windings. Featuring excellent appearance and safe operation, they are widely deployed across various sectors nationwide.
- ZHONGSHAO ‘s 35kV three phase oil immersed distribution transformers comply with ANSI C57.12.00 standards, as well as IEC 60076, GB 1097 (Power Transformers), and GB/T 6451 (Technical Parameters and Requirements for Three Phase Oil Immersed Power Transformers).
- Our oil immersed transformers are also extensively used in environments contaminated by oil and chemical substances.
Professional Oil Immersed Transformer Manufacturer In China
As a professional manufacturer of oil immersed transformers in China, ZHONGSHAO ‘s oil immersed transformers feature low operational noise and a compact structure. They are widely applicable in environments susceptible to oil and chemical contamination, meeting diverse application requirements. Our 35kV three phase oil immersed distribution transformers comply with ANSI C57.12.00 standards while meeting IEC 60076, GB 1097 (Power Transformers), and GB/T 6451 (Technical Parameters and Requirements for Three Phase Oil immersed Power Transformers) specifications. Contact us immediately for a quote.

Has three-phase distribution with fully immersed, Has over 60Hz and autotransformer with continuous control.

Round coil structure and multi-winding, has wide voltage capacity for higher power.

Multi-winding coil and has wide capacity for both frequency and voltage. The material is high quality and durable.

Power distribution and has wide capacity voltages suitable. Has a three phase distribution that ensures quality results.

Wide power voltage input and has large capacity that ensures power distribution with no delay. Manufactured with anti-corrosion metal.

High-voltage capacity with very up to expectation results. Has multi-phase that is suitable for higher voltage management.

Round coil structure with great oil immersion. Made with raw high-quality materials and has three phase distribution.

Ideal for voltage conversion, has wide input and output voltage. A great cooling method that ensures no overheating and internal damages.
What is an Oil Immersed Transformer?
Oil immersed transformers use insulating oil as both a cooling medium and an insulating medium. Within these transformers, both the windings and the core are submerged in insulating oil. The advantages of using insulating oil lie in its exceptional heat absorption capacity and insulating properties. These highly efficient characteristics make it suitable for outdoor large scale equipment requiring voltage conversion, such as outdoor power applications or large-scale industrial power systems.
How Does an Oil Immersed Transformer Work?

In fact, the operational process of oil immersed transformers is not particularly unique. It similarly uses the principle of electromagnetic induction, achieving voltage transformation through varying numbers of coil turns. Its components include a core, coils, and essential insulation and cooling systems, this is also where we employ the insulating oil.
During specific operation, current flowing through the iron core generates a magnetic field. The greater the number of coil turns, the stronger the induced electromotive force becomes. The transformation of voltage is precisely achieved through the difference in turns between the primary and secondary coils.
The distinctive feature of oil immersed transformers lies in their use of insulating oil as both the insulating and cooling medium. The core and windings within the equipment are fully submerged in this liquid. During operation, the insulating oil efficiently absorbs heat generated by electromagnetic induction, preventing overheating damage to the transformer itself and ensuring its stable, normal functioning. This capability is particularly crucial in high load applications, effectively mitigating the risk of failure.
Types Of Oil Immersed Transformers
Oil Immersed Single Phase Transformer
A single phase oil immersed transformer refers to a transformer that uses a single pair of windings for voltage transformation. Compared to the three phase type, it has a simpler construction and smaller footprint, though its load capacity is correspondingly more limited. It is suitable for rural areas with lower power demands or small scale industrial settings.
Oil Immerse Three Phase Transformer
Three phase oil immersed transformers are employed to achieve voltage transformation for three phase alternating current, capable of simultaneously supplying power to three circuits. Their windings are distributed across three columns of the same iron core, maintaining a 120°electrical phase difference. This configuration enables more efficient voltage transformation and supports operation under heavier loads, making them suitable for high electricity demand applications such as industrial parks and urban power distribution systems.
Advantages Of Oil Immersed Transformers

Cheaper
Compared to dry type transformers, oil immersed transformers are more cost effective, largely due to their lower manufacturing costs. Dry type transformers, particularly epoxy resin transformers, represent a relatively recent innovation in transformer technology, while oil immersed transformers benefit from more established manufacturing processes. Additionally, their simpler structure results in lower maintenance costs compared to dry type transformers.
Better Heat Dissipation Ability
As a thermal medium, insulating oil possesses excellent thermal conductivity, enabling it to efficiently absorb heat generated by the core and windings during operation. It maintains the equipment’s normal operating temperature even under high load conditions. Therefore, compared to dry type transformers, oil immersed transformers are better suited for high load operating applications.
Better Insulating Ability
From an insulation perspective, the properties of insulating oil also play a crucial role. It effectively fills gaps between windings, providing comprehensive insulation to prevent faults caused by leakage currents. This ensures more stable transformer operation and extends its service life.
Where Can An Oil Immersed Transformer Be Used?
Urban Distribution Networks
In the city’s power distribution network system, oil immersed transformers perform the critical task of voltage conversion. Even when installed in outdoor environments, they maintain stable operation, ensuring reliable power delivery to households throughout the city by elevating and reducing electrical current levels.
Large Scale Industrial Facilities
In large scale industrial applications, oil immersed transformers provide appropriately voltage regulated power supply for high capacity electrical equipment. They support the prolonged operational demands of industrial sectors, playing a critical role in mining, manufacturing, and many other fields.
Public Constructions
Oil immersed transformers are also necessary in the power distribution systems of public buildings, including hospitals, apartments, and office buildings. These transformers possess robust power supply capabilities, enabling voltage conversion for multiple electrical systems such as lighting and air conditioning. Additionally, you may need to use distribution panels to allocate current to different equipment circuits.
New Energy
In the field of new energy, oil immersed transformers convert the voltage generated by wind or photovoltaic power, enabling long distance transmission of electricity and ensuring its successful integration into the grid system.
How to choose a proper Oil Immersed Transformer?

Load Capacity
First, you need to identify a transformer with the appropriate rated capacity based on the specific power and load requirements of your application. The rated capacity of a transformer is typically indicated in its parameter table, and measured in kVA.
You also can directly consult the customer service forthis information. At the same time, when making your selection, you need to ensure that this value should be higher than the power and load demanded by your equipment to provide sufficient current support for operation.
Rating Voltage
The rated voltage of a transformer must also match the specific requirements of the electrical equipment it powers,this needs you to confirm the input and output voltage ranges of the transformer.
ZHONGSHAO offers oil immersed transformers with rated high voltage sides of 10kV, 20kV, and 35kV. The 10kV three phase oil immersed transformer features a fully enclosed structure, suitable for industrial and agricultural 10kV distribution systems in factories, mining areas, petrochemical plants, and various environments with oil contamination or chemical substances.
The 20kV model offers higher power supply capacity compared to the 10kV ones, further reducing energy loss for enhanced energy efficiency. While the 35kV three phase oil immersed distribution transformer has broader applications and complies with multiple standards including IEC 60076 and GB 1097.
According To The Used Environment
Similarly, you must also consider the specific application environment. Generally, oil immersed transformers should be placed in well ventilated areas without direct sunlight. If your application environment unavoidably involves corrosive conditions, you may need oil immersed transformers that have undergone anti corrosion surface treatment or dust proof and explosion proof processing.
Quality Inspection Certification
Safety certification is an essential reference point, particularly in the electrical field. You must verify that the selected oil immersed transformer holds compliance certificates that meet national or international standards. This serves as a crucial guarantee for both operational safety and long term reliability.
The Price
Price is also an important consideration. You should choose products with a high cost performance ratio based on your budget.
Maintenance Of An Oil Immersed Transformer
Regular inspection and maintenance are essential for oil immersed transformers. First, you need to maintain good cleaning habits by removing the dust or debris in time. During periodic inspections, you should check all transformer components for integrity and monitor for abnormal noise or overheating during operation, as well as inspecting for oil leaks. If an oil leak is detected, what you need to do first is to stop the machine as fast as possible and replace the transformer to prevent fire hazards or other safety risks.
A fully enclosed oil immersed transformer refers to a completely sealed transformer structure where all insulating oil and the iron core are contained within a single unit, without an external oil reservoir. One advantage of this design is its simplicity and compact footprint. In contrast, oil IMMERSED transformers with external oil reservoirs require additional tanks connected to the main body and maintain balanced internal and external pressures. Their benefit lies in accommodating larger volumes of insulating oil, making them suitable for higher load operations, though they necessitate more frequent maintenance and inspections.
ZHONGSHAO offers both fully enclosed and oil immersed transformer models. Contact us for more information.
Due to the unique nature of using liquid (insulating oil), the operating environment for oil immersed transformers must also be carefully selected and maintained under suitable conditions. For example, you should avoid placing it in extremely high temperature environments, as its maximum operating temperature should not exceed 85°C. This value is relatively safe and prevents oil degradation. To maintain optimal operating conditions, we recommend an average operating temperature of around 30°C.
Similarly, due to the flammability of the oil, there are important precautions you must be aware of during use. Specifically, operations should be conducted outdoors or in areas free of open flames whenever possible. Additionally, the building should ideally meet the appropriate fire resistance rating. In the event of a fire, you must prevent leakage of the insulating oil and implement isolation and fire extinguishing measures.
We provide a two years warranty and lifetime technical support, you only need to be responsible for the cost of materials.




