I. Product Description
The Oil-Immersed Transformer is a classic power transformation device that utilizes insulating oil as the core insulation and cooling medium. It fully immerses the high-permeability silicon steel sheet core and copper winding within a sealed oil tank, facilitating heat transfer through natural convection of the insulating oil. This transformer is capable of converting high-voltage grid voltages such as 10kV and 35kV into the commonly used low voltage of 0.4V at the user side, covering a safe capacity range from 10kVA to tens of thousands of kVA. It is currently the most widely used distribution equipment in industrial and mining power grids, outdoor substations, and large-scale power transmission and distribution scenarios. The entire series complies with the national industry standard GB/T 1094.7-2024.
II. execution standard
GB1094.1~2-1996 Power Transformers
GB1094.3~5-2003 Power Transformers
GB1094.4-2005 Power Transformers
GB/T6451-2008 Technical Parameters and Requirements for Three-phase Oil-immersed Power Transformers
III. Product Features
Excellent heat dissipation performance: Relying on the strong thermal conductivity of insulating oil, combined with external cooling fins/pipes, it achieves efficient heat exchange, ensuring stable temperature control even during long-term full-load operation, and is suitable for high-load continuous power supply scenarios.
Longer service life: Insulating oil can isolate oxygen and moisture, providing comprehensive protection for the iron core and windings, significantly delaying the aging of internal insulating materials. Under normal operating conditions, the service life can reach over 30 years.
Lower operation and maintenance costs: With a mature and reliable structure, simple troubleshooting and component replacement processes, the procurement and maintenance costs over the entire life cycle are significantly lower than those of Dry-type Transformers of the same capacity, making it suitable for remote outdoor sites.
Outstanding overload capacity: The oil-cooled thermal buffer space is ample, capable of withstanding 1.2-1.5 times the rated load impact for a short period of time, perfectly adapting to power consumption scenarios with large seasonal fluctuations such as rural power grids and industrial plant areas.
Wide range of application scenarios: Supporting outdoor pole mounting and deployment in open-air substations, from ordinary urban and rural distribution networks to large power plant step-up stations, corresponding mature models can be found, with strong technical implementation coverage.
IV. Performance characteristics
Compared with the "8" series products, the S13 series products have a 14.88% reduction in no-load loss, a 10.47% reduction in load loss, and a 11.14% reduction in total loss. The energy-saving benefits are significant, and there are good social benefits.
| Model | Material | Size |
| S9/S11/S13 | Copper/Aluminum | 150*100*150cm |
At Jihui Electric Group Co., Ltd., we specialize in the research, development, manufacturing, and supply of medium and low voltage power transmission and distribution equipment up to 35kV. Our OEM 100kVA, 200kVA, and 315kVA oil-immersed double-winding transformers are designed to provide stable, efficient, and customized power distribution solutions for industrial, commercial, renewable energy, and infrastructure applications.
As a Transformer Manufacturer, we understand that every project has different requirements. Some customers need compact transformers for small factories, while others require customized solutions for industrial production lines or power distribution systems. That is why we provide OEM transformer manufacturing services, allowing customers to select suitable specifications according to their actual applications.
Our oil-immersed double-winding transformers are designed with high voltage and low voltage windings separated by a reliable insulation system. This structure allows efficient voltage conversion while maintaining stable electrical performance during long-term operation.
The available capacity range includes 100kVA, 200kVA, and 315kVA models, covering different power requirements. These transformers are widely used in factories, commercial buildings, substations, industrial parks, and other medium voltage distribution systems.
Through professional engineering design, strict manufacturing control, and complete factory testing, we provide customers with reliable OEM oil immersed transformer solutions that support safe and continuous power operation.
An oil-immersed double-winding transformer is an electrical device that transfers electrical energy between different voltage levels through electromagnetic induction. It uses transformer oil as insulation and cooling medium, helping the transformer maintain stable operation under different load conditions.
The term “double-winding transformer” refers to the two main winding systems inside the transformer: the high voltage winding and the low voltage winding.
The high voltage winding receives electricity from the medium voltage power network, while the low voltage winding outputs electricity at a lower voltage level suitable for electrical equipment and end users.
For example, in an industrial power distribution system, electricity may enter the transformer at a medium voltage level and then be converted into a lower voltage suitable for factory machines, lighting systems, and control equipment.
Our OEM 100kVA, 200kVA, and 315kVA oil-immersed double-winding transformers are designed to provide reliable voltage conversion with excellent insulation performance, efficient cooling, and long service life.
The working principle of our Oil-Immersed Transformer is based on electromagnetic induction. Although the technology involves electrical engineering principles, the basic concept is simple: the transformer changes voltage levels while transferring electrical energy.
The transformer mainly consists of a magnetic core, high voltage winding, low voltage winding, transformer oil, tank structure, insulation components, and protection accessories.
When alternating current flows through the high voltage winding, it creates a changing magnetic field inside the transformer core. This magnetic field induces voltage in the low voltage winding.
By controlling the ratio between the number of turns in the high voltage and low voltage windings, the transformer can achieve the required voltage conversion.
During operation, electrical resistance and magnetic effects generate heat. Transformer oil absorbs this heat and transfers it to the transformer tank surface, where it is released into the surrounding environment.
This cooling method allows oil-immersed transformers to handle continuous operation and maintain reliable performance over long periods.
When we manufacture transformers, we focus on real operating conditions. A transformer should not only meet technical specifications but also provide stable performance after years of operation.
Different customers have different electrical systems, installation environments, and technical standards. A standard transformer may not always be the best solution.
Our OEM manufacturing service allows customers to customize transformer specifications according to their requirements, including capacity, voltage ratio, winding material, protection accessories, and structural design.
This flexible approach helps customers receive transformer products that better match their projects.
We provide different capacity options including 100kVA, 200kVA, and 315kVA oil immersed transformers.
The 100kVA transformer is suitable for smaller power distribution applications, while 200kVA and 315kVA models are designed for higher electrical loads.
Customers can select suitable capacity according to equipment power demand, future expansion plans, and installation conditions.
| Transformer Capacity | Typical Application | Main Advantage |
|---|---|---|
| 100kVA Oil-immersed Transformer | Small factories, workshops, commercial facilities | Compact design and reliable power supply |
| 200kVA Oil-immersed Transformer | Medium industrial facilities and buildings | Balanced capacity and efficiency |
| 315kVA Oil-immersed Transformer | Industrial plants and larger distribution systems | Higher load capability and stable operation |
Source: Capacity application classification is based on common distribution transformer selection practices used in industrial and commercial power systems.
Transformer oil plays an important role in oil-immersed transformer operation. It provides electrical insulation between internal components and helps remove heat generated during operation.
The oil cooling system improves heat dissipation performance and allows the transformer to operate reliably under continuous electrical loads.
The double-winding design provides reliable separation between high voltage and low voltage circuits.
This structure improves electrical safety and helps maintain stable voltage conversion performance during operation.
Insulation quality directly affects transformer reliability. Our transformers use reliable insulation materials and controlled manufacturing processes to reduce electrical stress and improve service life.
The insulation system helps protect internal components from moisture, temperature changes, and electrical pressure.
According to customer requirements, our OEM oil-immersed double-winding transformers can be manufactured with copper or aluminum winding.
Copper winding provides excellent electrical conductivity and strong performance, while aluminum winding provides advantages in weight and cost efficiency.
We help customers select the suitable winding material based on project requirements and operating conditions.
At Jihui Electric, we focus on improving transformer reliability through engineering design, material selection, and manufacturing accuracy.
The transformer core directly affects energy efficiency. We use optimized core structures and suitable electrical steel materials to reduce magnetic losses.
A low-loss core helps improve transformer efficiency and reduce unnecessary energy consumption during long-term operation.
Transformers often operate for many years in different environments. The mechanical structure must provide enough strength to protect internal components.
Our transformer tanks and internal structures are designed for stable operation under normal working conditions.
Our production process includes engineering review, material inspection, component manufacturing, assembly, oil filling, testing, and final inspection.
Every production stage is controlled to ensure consistent product quality.
| Item | 100kVA | 200kVA | 315kVA |
|---|---|---|---|
| Rated Capacity | 100kVA | 200kVA | 315kVA |
| Application Level | Small power systems | Medium power systems | Higher power distribution systems |
| Typical Users | Small workshops and buildings | Factories and commercial facilities | Industrial plants and larger projects |
| Main Benefit | Compact and economical | Balanced performance | Higher load support |
Source: Comparison based on common transformer capacity selection requirements in medium voltage distribution applications.
During our experience in the power equipment industry, we have worked with customers from many different fields. We understand that each application has different requirements for transformer capacity, installation conditions, operating environment, and reliability.
Our OEM 100kVA, 200kVA, and 315kVA oil-immersed double-winding transformers are designed for a wide range of medium voltage distribution applications. With stable voltage conversion, efficient cooling, and durable construction, these transformers provide reliable power solutions for industrial and commercial users.
Manufacturing facilities require continuous and stable electricity to operate production lines, motors, automation systems, and industrial equipment. Any unexpected power interruption may reduce production efficiency and increase operating costs.
Our oil-immersed distribution transformers provide reliable power conversion from medium voltage systems to low voltage equipment. They are commonly used in machinery factories, automotive production plants, electronic manufacturing facilities, metal processing industries, and industrial parks.
The oil cooling system and strong insulation structure help maintain stable transformer performance during long-term operation.
Commercial buildings require safe and reliable electrical systems for lighting, elevators, air conditioning, security systems, and other equipment.
Our OEM oil immersed transformers can be customized according to building power requirements. The 100kVA, 200kVA, and 315kVA models provide flexible choices for different project scales.
They are suitable for office buildings, shopping centers, hotels, schools, hospitals, and other public facilities that require dependable electricity supply.
The development of renewable energy has increased the demand for reliable transformer equipment. Solar power systems, distributed energy projects, and other renewable applications require transformers to connect generated electricity with distribution networks.
Our three-phase oil-immersed transformers provide stable voltage conversion and support efficient power transmission in renewable energy applications.
Distribution networks depend on transformers to transfer electricity safely between different voltage levels. Our medium voltage transformers are suitable for local substations, industrial power networks, and utility distribution systems.
The double-winding structure provides reliable separation between high voltage and low voltage circuits, helping maintain safe and stable operation.
Mining and heavy industries often operate under demanding conditions. Electrical equipment may face dust, vibration, temperature changes, and continuous load requirements.
Our oil-immersed double-winding transformers are designed with durable structures and reliable insulation systems to support challenging industrial environments.
| Application Field | Main Requirement | Transformer Advantage |
|---|---|---|
| Manufacturing Industry | Stable power for continuous production | Reliable operation and efficient cooling |
| Commercial Facilities | Safe and dependable electricity | Flexible capacity selection |
| Renewable Energy | Stable grid connection | Efficient voltage conversion |
| Industrial Infrastructure | Long service life | Durable structure and customization |
Source: Application information is based on common medium voltage transformer applications and industrial power distribution practices.
At Jihui Electric, we believe transformer quality starts from the manufacturing process. Every step, from engineering design to final testing, affects the reliability and service life of the transformer.
Before production begins, our engineering team communicates with customers to confirm technical requirements, including transformer capacity, voltage ratio, frequency, winding material, installation environment, and protection requirements.
For OEM transformers, we adjust the design according to customer specifications to ensure the final product matches the application.
The transformer core is an important component that affects energy efficiency and operating performance.
We use high-quality electrical steel materials and accurate processing methods to produce reliable core structures. The optimized core design helps reduce magnetic losses and improve transformer efficiency.
The winding process requires precision because winding quality directly influences electrical performance.
Our production team controls conductor arrangement, insulation distance, and mechanical strength during manufacturing. According to customer requirements, we provide copper or aluminum winding options.
After core and winding production are completed, our technicians assemble the transformer body, install internal components, and complete electrical connections.
The assembly process includes detailed inspections to ensure structural stability and reliable operation.
Transformer oil provides both insulation and cooling functions. During manufacturing, qualified insulating oil is filled into the transformer under controlled conditions.
The sealing process helps prevent oil leakage and protects internal components from external environmental influences.
Before delivery, every transformer undergoes professional testing. We inspect electrical performance, insulation condition, mechanical structure, and product appearance.
These tests help confirm that the transformer meets technical requirements before shipment.
| Quality Control Stage | Main Inspection Items | Purpose |
|---|---|---|
| Raw Material Inspection | Core, conductor, insulation materials | Ensure material reliability |
| Production Inspection | Winding and assembly quality | Maintain manufacturing accuracy |
| Electrical Testing | Insulation, resistance, performance tests | Verify safe operation |
| Final Inspection | Appearance and technical documents | Ensure delivery quality |
Source: Quality inspection procedures are based on transformer manufacturing practices and IEC 60076 series requirements.
Our OEM transformer solutions can be customized according to customer requirements. The following table shows typical specifications for these oil-immersed double-winding transformers.
| Parameter | Typical Specification |
|---|---|
| Transformer Type | Oil-immersed Double-winding Transformer |
| Capacity Range | 100kVA / 200kVA / 315kVA |
| Phase | Three Phase |
| Voltage Level | Medium Voltage Distribution Application |
| Winding Material | Copper / Aluminum (Cu/Al) |
| Cooling Method | Oil Natural Air Natural (ONAN) |
| Customization | OEM production available |
Source: Typical specifications based on common distribution transformer configurations.
Choosing a transformer supplier means choosing long-term reliability for your electrical system. At Jihui Electric, we focus on providing stable products, professional engineering support, and flexible manufacturing solutions.
Jihui Electric Group Co., Ltd. specializes in medium and low voltage power transmission and distribution equipment up to 35kV.
Our product range includes oil-immersed transformers, Dry-type Transformers, Cable accessories, Cable distribution boxes, ring main units, Prefabricated Substations, combination transformers, SF6 load switches, and Vacuum circuit breakers.
This complete product range allows us to support customers with integrated power distribution solutions.
We have established professional quality management procedures and obtained ISO9001 quality management system certification, ISO14001 environmental management system certification, and ISO45001 occupational health and safety management system certification.
Our quality control covers material selection, production processes, electrical testing, and final inspection.
OEM customers often have specific requirements for transformer dimensions, electrical parameters, and application conditions.
We provide customized transformer solutions including:
Capacity customization
Voltage ratio adjustment
Copper or aluminum winding selection
Protection accessory configuration
Special project requirements
For overseas customers, we provide complete export support including technical communication, production arrangement, quality inspection, packaging, and transportation coordination.
According to transformer specifications and destination requirements, we arrange suitable shipping methods including sea transportation, land transportation, or combined logistics.
Professional protective packaging is used to prevent moisture, vibration, and impact during transportation.
An oil-immersed double-winding transformer is a transformer that uses insulating oil for cooling and insulation while using separate high voltage and low voltage windings for voltage conversion.
These transformers are commonly used in factories, commercial buildings, industrial facilities, substations, and other medium voltage power distribution systems.
Yes. We provide OEM customization according to customer requirements, including voltage, capacity, winding material, structure, and accessories.
Yes. We support both copper and aluminum winding options based on customer requirements.
We guarantee quality through strict material inspection, controlled manufacturing processes, complete electrical testing, and final inspection before shipment.
At Jihui Electric Group Co., Ltd., we are committed to providing reliable and efficient power distribution solutions for customers worldwide.
Our OEM 100kVA, 200kVA, and 315kVA oil-immersed double-winding transformers combine flexible customization, reliable performance, and professional manufacturing capability.
With advanced production processes, strict quality management, and international delivery experience, we help customers build safer and more stable electrical systems.
If you are looking for an OEM oil immersed transformer manufacturer or need customized 100kVA, 200kVA, and 315kVA transformer solutions, Jihui Electric is ready to support your project with professional products and services.
JiHui Electric Group Co., Ltd , high-end website construction, foreign trade website construction, marketing website construction, website optimization, development websites, corporate network marketing, search engine promotion, wechat mini program, corporate mailbox, short video operation, etc.
No. 161 Jingliu Road, Yueqing Economic Development Zone, Yueqing City, Zhejiang Province, China
jh.power@jihuielec.com
+86 18967711966
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