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 factory customization of 11/0.4kV, 250kVA, and 500kVA power transformers provides reliable voltage conversion solutions for industrial plants, commercial buildings, renewable energy projects, and electrical distribution systems.
We understand that every power project has different requirements. Some customers need compact transformers for limited installation spaces, while others require customized transformer designs for industrial production lines or infrastructure projects. Therefore, we focus on providing flexible transformer solutions instead of only offering standard products.
Our 11/0.4kV power transformers are designed to convert medium voltage electricity from an 11kV network into a 0.4kV low voltage output suitable for end-use equipment. With available capacities of 250kVA and 500kVA, these transformers can meet different power demands for factories, workshops, buildings, and other electrical systems.
Through professional engineering design, strict production control, and complete testing procedures, we ensure our customized distribution transformers provide stable operation, efficient performance, and long service life.
An 11/0.4kV power transformer is an electrical device used to reduce voltage from medium voltage levels to low voltage levels. In many industrial and commercial power systems, electricity is transmitted at higher voltage levels to improve transmission efficiency. Before the electricity reaches equipment and users, transformers reduce the voltage to a safer and usable level.
The term “11/0.4kV” describes the voltage conversion ratio. The primary side of the transformer receives electricity at 11kV, while the secondary side outputs electricity at 0.4kV, which is commonly used for low voltage distribution systems.
Our 250kVA and 500kVA power transformers are designed according to customer application requirements. They are suitable for systems that require stable electricity supply, efficient operation, and reliable protection.
Unlike simple electrical components, transformers need to operate continuously for many years. A reliable transformer must handle changing loads, temperature variations, and different environmental conditions. This is why we pay attention to every detail during design and manufacturing.
The working principle of our three phase distribution transformer is based on electromagnetic induction. The transformer transfers electrical energy between two circuits while changing the voltage level.
The main components include the magnetic core, high voltage winding, low voltage winding, insulation system, cooling structure, and protective accessories.
When alternating current enters 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 adjusting the number of winding turns between the two sides, the transformer can achieve the required voltage conversion.
For an 11kV to 0.4kV transformer, the high voltage side connects to the medium voltage distribution network, while the low voltage side supplies electricity to industrial machines, lighting systems, control equipment, and other electrical loads.
During operation, the transformer generates a certain amount of heat due to electrical resistance and magnetic losses. Our transformer design includes effective cooling and insulation systems to maintain safe operating temperatures.
When we manufacture power transformers, we focus on practical customer needs. A transformer should not only meet technical specifications but also provide reliable performance throughout its service life.
Different projects have different technical requirements. Installation space, voltage conditions, environmental factors, and load characteristics can vary greatly between applications.
Our factory customization service allows customers to adjust transformer specifications according to their actual needs. We can support customized solutions including transformer capacity, winding material, protection configuration, and structural design.
This flexible approach helps customers obtain transformers that better match their electrical systems.
The 11kV voltage level is widely used in industrial and commercial power distribution systems. Our transformers are designed to provide stable voltage conversion between medium voltage networks and low voltage applications.
The optimized electrical structure helps maintain reliable operation under different load conditions, reducing the risk of voltage instability and unexpected downtime.
Different facilities require different power capacities. A small workshop may need a 250kVA transformer, while a larger production facility may require a 500kVA unit.
By providing multiple capacity options, we help customers select suitable transformer solutions according to their actual power consumption.
| Transformer Capacity | Typical Application | Main Advantages |
|---|---|---|
| 250kVA Power Transformer | Small factories, workshops, commercial buildings | Compact design, suitable for medium power loads |
| 500kVA Power Transformer | Industrial plants, larger facilities, power distribution systems | Higher capacity and stronger load support |
Source: Capacity application comparison based on common industrial transformer selection practices and medium voltage distribution engineering requirements.
Energy efficiency has become increasingly important because transformers often operate continuously. Even small reductions in energy loss can create meaningful savings over many years of operation.
Our transformer design focuses on reducing unnecessary losses through optimized core materials, improved winding structures, and accurate manufacturing processes.
Insulation quality directly affects transformer safety and service life. Our transformers use reliable insulation systems to protect internal components from electrical stress and environmental influences.
The insulation structure helps maintain stable performance under different operating conditions, including temperature changes and continuous electrical loads.
Effective heat management is important for transformer reliability. Our transformer structures are designed to improve heat dissipation and maintain suitable operating temperatures.
A proper cooling system helps reduce thermal stress and supports long-term stable operation.
At Jihui Electric, we believe transformer quality comes from engineering details. From material selection to final inspection, every step affects the final performance of the product.
The transformer core plays an important role in electrical efficiency. We use suitable electrical steel materials and optimized core structures to reduce magnetic losses.
A high-quality core helps improve efficiency, reduce operating noise, and support stable transformer performance.
Depending on project requirements, our 250kVA and 500kVA transformers can be manufactured with copper or aluminum winding.
Copper winding provides excellent conductivity and strong electrical performance, while aluminum winding offers advantages in weight and cost efficiency.
We select suitable winding solutions according to customer requirements, application conditions, and project standards.
A transformer must withstand long-term operation and environmental changes. Our transformer structure is designed with mechanical strength and operational reliability in mind.
This helps ensure stable performance in industrial, commercial, and infrastructure applications.
| Item | 250kVA Transformer | 500kVA Transformer |
|---|---|---|
| Rated Capacity | 250kVA | 500kVA |
| Recommended Application | Small and medium power distribution | Medium and larger power systems |
| Load Capability | Suitable for moderate electrical loads | Suitable for higher power demand |
| Common Users | Workshops, small buildings, local distribution | Factories, industrial facilities, commercial complexes |
Source: Transformer capacity comparison based on general power distribution application requirements.
During our years of manufacturing power distribution equipment, we have learned that each industry has different requirements for transformer performance. Some customers need stable power for continuous production, while others focus on energy efficiency, safety, and long-term reliability.
Our factory customized 11/0.4kV, 250kVA, and 500kVA power transformers are designed to support different electrical applications. With flexible customization, reliable voltage conversion, and durable construction, our transformers are widely used in industrial, commercial, and infrastructure projects.
Factories depend on stable electricity to operate production equipment, automation systems, motors, and control devices. Any power interruption may affect production efficiency and increase operating costs.
Our 11kV to 0.4kV transformers provide reliable power conversion for industrial plants, workshops, and manufacturing facilities. The transformers help ensure that electrical equipment receives stable low voltage power after conversion from the medium voltage network.
They are suitable for industries such as machinery manufacturing, automotive production, electronic equipment manufacturing, metal processing, and industrial parks.
Commercial buildings require safe and stable electrical systems for lighting, elevators, HVAC systems, security systems, and daily operations.
Our customized distribution transformers are used in office buildings, shopping centers, hotels, schools, hospitals, and other public facilities where reliable power supply is important.
The flexible design allows customers to select suitable transformer capacity according to building load requirements.
The growth of renewable energy has increased the demand for reliable transformer solutions. Solar power stations, distributed energy systems, and other renewable projects need transformers to connect generated electricity with local power networks.
Our medium voltage power transformers support efficient energy transfer and stable operation for renewable energy applications.
Infrastructure projects such as transportation facilities, urban construction projects, and public utilities require dependable electrical equipment.
Our 11/0.4kV power transformers provide stable voltage conversion solutions for infrastructure systems that require long service life and reliable operation.
Modern agricultural operations use many electrical devices, including irrigation systems, storage equipment, processing machines, and automation systems.
Our 250kVA and 500kVA transformers provide practical solutions for agricultural power distribution systems that require stable electricity supply.
| Application Industry | Main Electrical Requirement | Transformer Advantage |
|---|---|---|
| Manufacturing Industry | Continuous and stable power supply | Reliable voltage conversion and durable structure |
| Commercial Buildings | Safety and efficient operation | Flexible capacity selection and stable performance |
| Renewable Energy | Efficient power transmission | Suitable for medium voltage systems |
| Infrastructure | Long-term reliability | Customized design and strong adaptability |
Source: Application classification is based on common medium voltage transformer applications and power distribution engineering practices.
At Jihui Electric, we believe a reliable transformer starts with careful manufacturing. Every stage, from design to final testing, affects the safety and service life of the product.
Before production begins, our engineering team reviews customer requirements, including voltage level, rated capacity, installation environment, operating conditions, and technical standards.
For customized 11/0.4kV transformers, we adjust the design according to actual project needs. This helps ensure the transformer matches the customer's electrical system.
The transformer core is one of the most important components because it affects efficiency and energy loss.
We use suitable electrical steel materials and accurate processing methods to produce stable core structures. A well-designed core helps reduce magnetic losses and improve operating efficiency.
The winding process requires high precision because winding quality directly affects electrical performance.
During production, we control conductor arrangement, insulation distance, and mechanical strength. Customers can choose copper or aluminum winding based on application requirements.
After core and winding production, our technicians complete transformer assembly, including internal component installation, electrical connections, and structural inspection.
Each assembly step is carefully controlled to ensure mechanical stability and reliable operation.
Before delivery, every transformer undergoes professional testing. We inspect electrical performance, insulation condition, structural quality, and appearance.
These tests help us confirm that each transformer meets technical requirements before shipment.
| Inspection Stage | Main Test Item | Quality Objective |
|---|---|---|
| Material Inspection | Core, winding, insulation materials | Ensure reliable raw materials |
| Manufacturing Inspection | Assembly accuracy and process control | Maintain consistent quality |
| Electrical Testing | Insulation, resistance, performance tests | Confirm safe operation |
| Final Inspection | Appearance and technical documents | Ensure delivery standards |
Source: Quality control procedures are based on transformer manufacturing practices and IEC 60076 series requirements.
The following table shows typical specifications for our customized distribution transformers. Specific parameters can be adjusted according to customer requirements.
| Parameter | Typical Specification |
|---|---|
| Rated Voltage | 11kV / 0.4kV |
| Capacity Options | 250kVA / 500kVA |
| Transformer Type | Three Phase Distribution Transformer |
| Winding Material | Copper / Aluminum (Cu/Al) |
| Frequency | 50Hz / 60Hz |
| Application | Industrial, commercial, infrastructure power systems |
| Customization | Available according to project requirements |
Source: Typical technical specifications based on common medium voltage distribution transformer configurations.
Choosing the right transformer supplier is important because transformer reliability directly affects the operation of the entire electrical system. At Jihui Electric, we focus on providing practical solutions, stable products, and professional support.
Jihui Electric Group Co., Ltd. specializes in medium and low voltage power transmission and distribution equipment up to 35kV.
Our products include power 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 provide integrated solutions for different electrical projects.
We operate according to international quality management requirements and have obtained ISO9001 quality management certification, ISO14001 environmental management certification, and ISO45001 occupational health and safety certification.
Our quality system covers material selection, production processes, testing procedures, and delivery inspection.
Every project has different requirements. Our factory customization service allows customers to adjust transformer specifications according to their applications.
We can provide customized solutions including:
Voltage ratio customization
250kVA and 500kVA capacity options
Copper or aluminum winding selection
Protection accessories configuration
Special installation requirements
For overseas customers, we provide complete export services including technical communication, production scheduling, inspection support, packaging, and transportation arrangement.
According to product size and destination, we select suitable transportation methods such as sea transportation, land transportation, or combined logistics solutions.
Professional packaging methods are used to protect transformers from moisture, vibration, and impact during transportation.
An 11/0.4kV transformer is used to reduce medium voltage electricity from 11kV to 0.4kV for industrial equipment, commercial facilities, and other low voltage electrical systems.
The main difference is rated capacity. A 500kVA transformer can support higher electrical loads compared with a 250kVA transformer, making it suitable for larger facilities.
Yes. We provide factory customization services based on voltage requirements, capacity, winding materials, installation conditions, and technical specifications.
Yes. We support both copper and aluminum winding solutions according to customer requirements and application conditions.
We ensure quality through strict material inspection, controlled manufacturing processes, electrical testing, and final inspection before delivery.
At Jihui Electric Group Co., Ltd., we are committed to providing safe, reliable, and efficient power distribution solutions for customers worldwide.
Our factory customized 11/0.4kV, 250kVA, and 500kVA power transformers combine flexible design, reliable performance, and professional manufacturing capability.
From industrial facilities and commercial buildings to renewable energy projects and infrastructure systems, our transformers help customers build stable and efficient electrical networks.
If you are looking for a customized 11kV to 0.4kV transformer manufacturer or need a reliable 250kVA and 500kVA power transformer solution, 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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