4000kVA Oil Immersed Transformer
4000kVA Oil Immersed Transformer is designed for medium and large-scale power distribution systems that require high reliability, strong overload capacity, and long-term stable operation. The transformer adopts a fully sealed oil-immersed structure, effectively preventing moisture ingress and oil oxidation, thereby extending service life and reducing maintenance frequency. The transformer features excellent thermal performance and robust insulation strength, ensuring stable operation under continuous load or fluctuating grid conditions. Advanced oil circulation and cooling structure enhance heat dissipation, while precise manufacturing processes guarantee low noise and high mechanical strength.
- Primary Voltage Ratings 34.5-19.92/13.8-7.957, 24.94, 26.25, 33 or others
- Secondary Voltage Ratings 480/277V, 400/230V, 380/220V or customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Oil immersed distribution transformer
- BIL 30/95kV
- Standards IEEE, ANSI, NEMA, IEC, CE
- Application industrial parks, manufacturing plants, power substations
- Power Rating 4000kVA
- Certificate UL, CESI, IEEE
- Cooling Method ONAN, ONAN/ONAF, KNAN, KNAN/KNAF
- Oil Mineral Oil or FR3
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
4000kVA Oil Immersed Transformer
Technical Specifications
Accessories
| Rated Power | 4000 kVA | |
| Rating Primary Voltage | 2.4 - 34.5kV | |
| Secondary Voltage | 480/277V 400/230V 380/220V Customized |
|
| Frequency | 50/60Hz | |
| Vector Group | Dyn11, Yyn0, Dyn5 | |
| Winding Material | Aluminum/Copper | |
| Efficiency | As IEEE, Doe 2016, CAS Std or Customized | |
| Impedance Voltage | Nominal 2% or Customized 1.1 - 5.75% | |
| Altitude | ≤1,000m or Customized | |
| Color | ANSI 70 Light gray/Munsell 7GY3.29/1.5 or customized, etc | |
| Tank material | Mild Steel, 304 Stainless Steel | |
| Insulating Oil Weight | 850 kg | |
| Total Weight | 5000 kg | |
| Outline Dimensions（L×W×H）in. | 2650 × 1650 × 2450（mm) | |
| HV Bushing |
| LV Bushing |
| Tap changer |
| Oil level gauge |
| Oil temperature indicator |
| Pressure relief device |
| Pressure vacuum gauge |
| Lifting hook for complete transformer |
| Name plate |
| Radiators |
| Oil upper filtering valve |
| Oil drain valve with 3/8" sampler |
Customization Optional
4000kVA Oil Immersed Transformer
The 4000kVA Oil Immersed Transformer can be customized to meet diverse project requirements and grid conditions. Voltage ratings can be tailored according to local distribution standards, including primary and secondary voltage combinations suitable for industrial plants, substations, and utility networks. Tap changer configurations are available in off-load or on-load options, allowing flexible voltage regulation to ensure stable output under varying load conditions. Insulation class, temperature rise limits, and cooling methods can also be adjusted to align with specific operational environments.
In addition to electrical parameters, mechanical and structural customization is supported. The transformer tank can be designed with corrugated or flat-wall construction, and protective coatings can be selected for coastal, high-humidity, or high-pollution areas. Accessories such as oil level indicators, pressure relief devices, and online monitoring interfaces may be configured based on project needs. These customization options ensure the 4000kVA oil immersed transformer integrates seamlessly into different power systems while maintaining safety, efficiency, and long-term reliability.
Packing and Shipping
4000kVA Oil Immersed Transformer
Each 4000kVA Oil Immersed Transformer undergoes a strict pre-packing inspection to ensure all components meet quality and safety requirements before shipment. The transformer body is carefully cleaned, dried, and sealed to prevent contamination during transportation. Sensitive accessories are securely fixed or packed separately to avoid mechanical damage. Moisture-proof materials are applied to protect insulation performance throughout the logistics process.
For packing, the transformer is mounted on a reinforced steel or wooden base designed to support heavy loads and prevent displacement. The main body is wrapped with protective films and shock-absorbing materials to minimize vibration and impact during transit. External packing complies with international shipping standards, making it suitable for long-distance sea freight, rail transport, or road delivery. Clear handling marks and lifting instructions are displayed to ensure safe loading and unloading.
Shipping arrangements for the 4000kVA oil immersed transformer are flexible and can be tailored to customer requirements. The factory supports FOB, CIF, and other international trade terms, coordinating with experienced logistics partners to ensure timely and secure delivery. Detailed shipping documents, including packing lists, test reports, and certificates of conformity, are prepared to facilitate smooth customs clearance.
Upon arrival, guidance for unloading and on-site inspection can be provided to ensure the transformer is received in optimal condition. Proper packing and professional shipping management reduce transportation risks and help maintain the performance and integrity of the 4000kVA oil immersed transformer from factory to final installation site.
For packing, the transformer is mounted on a reinforced steel or wooden base designed to support heavy loads and prevent displacement. The main body is wrapped with protective films and shock-absorbing materials to minimize vibration and impact during transit. External packing complies with international shipping standards, making it suitable for long-distance sea freight, rail transport, or road delivery. Clear handling marks and lifting instructions are displayed to ensure safe loading and unloading.
Shipping arrangements for the 4000kVA oil immersed transformer are flexible and can be tailored to customer requirements. The factory supports FOB, CIF, and other international trade terms, coordinating with experienced logistics partners to ensure timely and secure delivery. Detailed shipping documents, including packing lists, test reports, and certificates of conformity, are prepared to facilitate smooth customs clearance.
Upon arrival, guidance for unloading and on-site inspection can be provided to ensure the transformer is received in optimal condition. Proper packing and professional shipping management reduce transportation risks and help maintain the performance and integrity of the 4000kVA oil immersed transformer from factory to final installation site.
32
32 years of industry experience
Manufacturer Test
4000kVA Oil Immersed Transformer
Progress Test
The 4000kVA Oil Immersed Transformer is subjected to a comprehensive progress test during each critical production stage. Core assembly inspection ensures precise lamination alignment to minimize losses, while winding tests verify dimensional accuracy and conductor integrity. Insulation resistance and ratio checks are conducted repeatedly to confirm electrical stability of the 4000kVA oil immersed transformer before tanking. These progress tests help identify potential issues early, ensuring consistent quality and performance throughout manufacturing.
Design Tests
All transformers will be tested after finishing the production, test items as follows:
♦ Insulation Power Factor
♦ Ratio, Polarity, and Phase Relation
♦ Winding Resistance
♦ Impulse Tests
♦ On load Loss Test
♦ No Load Loss Test
♦ Leak Test
♦ DC Insulation Resistance Test
♦ Transformer Turns Ratio/TTR (All Tap Voltages)
♦ Impedance Voltage & Load Loss (Rated Voltage)
♦ Induced Voltage
♦ Lightning Impulse
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)
Transformer Factory Acceptance Test
The 4000kVA Oil Immersed Transformer undergoes a full Factory Acceptance Test to verify compliance with technical specifications and international standards. Tests include winding resistance measurement, voltage ratio verification, insulation power factor testing, and applied voltage withstand tests. Each FAT item directly evaluates the performance of the 4000kVA oil immersed transformer, ensuring electrical safety, stable operation, and long-term reliability before shipment. No-load and load loss measurements, temperature rise simulation, and oil dielectric strength tests are performed to validate design efficiency. By completing a systematic FAT process, the manufacturer confirms that the 4000kVA oil immersed transformer is ready for installation and capable of handling demanding power distribution tasks.
Routine Test - Temperature Rise
Purpose of Testing
The purpose of the temperature rise test is to detect the temperature change of the equipment under working conditions by applying the rated load current or higher load current to ensure that the insulation performance of the equipment will not be degraded or damaged due to overheating during operation.
Testing Equipment
Temperature rise tester (e.g. OMRON, FLIR, Extech, etc.)
Heating source (e.g. electric heater, heater belt, or adjustable constant temperature heater, the specific power is selected according to the equipment requirements)
Temperature sensor (e.g. RTD sensor, thermocouple, to ensure accurate measurement)
Heating source (e.g. electric heater, heater belt, or adjustable constant temperature heater, the specific power is selected according to the equipment requirements)
Temperature sensor (e.g. RTD sensor, thermocouple, to ensure accurate measurement)
Pre-Test Preparation
Disconnect the device from the power supply and ensure that the device is properly grounded and discharged.
Ensure that the connection terminals and wiring are firm to avoid looseness affecting the test results.
Test under suitable environmental conditions: relative humidity below 75%, no rain (recommended temperature: 20-30°C).
Ensure that the connection terminals and wiring are firm to avoid looseness affecting the test results.
Test under suitable environmental conditions: relative humidity below 75%, no rain (recommended temperature: 20-30°C).
Test Progress
Connect the Test Instrument:
Connect the test instrument correctly to the electrical terminals and temperature measurement points of the device under test (such as windings, cores, oil temperature measurement elements, etc.).
Initial condition record:
Measure and record ambient temperature, humidity, and atmospheric pressure at the start of the test.
Make sure the device is cold at the start.
Connect the test instrument correctly to the electrical terminals and temperature measurement points of the device under test (such as windings, cores, oil temperature measurement elements, etc.).
Initial condition record:
Measure and record ambient temperature, humidity, and atmospheric pressure at the start of the test.
Make sure the device is cold at the start.
Measure and Record
Record the following parameters regularly:
Temperature of each winding (by resistance method or temperature sensor)
Core temperature
Oil temperature (for oil-immersed equipment)
Current, voltage and power at the equipment end
Duration of load
Record changes in ambient temperature.
Temperature of each winding (by resistance method or temperature sensor)
Core temperature
Oil temperature (for oil-immersed equipment)
Current, voltage and power at the equipment end
Duration of load
Record changes in ambient temperature.
Temperature Correction
Correct the measured winding temperature rise (equipment temperature - ambient temperature) to the reference ambient temperature (usually 20°C or as required by the standard).
Repeat Testing (if necessary)
Correct the measured winding temperature rise (equipment temperature - ambient temperature) to the reference ambient temperature (usually 20°C or as required by the standard).
Evaluation Criteria (Reference)
The maximum temperature rise of the winding should not exceed the product standard or the manufacturer's specified value (for example: Class A insulation: ≤60°C temperature rise
Class B insulation: ≤80°C temperature rise
Class F insulation: ≤100°C temperature rise)
Class B insulation: ≤80°C temperature rise
Class F insulation: ≤100°C temperature rise)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Suitable for industrial parks, manufacturing plants, power substations and large commercial complexes, providing stable and safe power conversion and distribution for medium and high load power systems.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
Product Packaging
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What is a Transformer?A transformer is an electrical device used to change the voltage of alternating current (AC). It works on the principle of electromagnetic induction, converting high-voltage current into low-voltage current or low-voltage current into high-voltage current. Transformers are widely used in power transmission, distribution systems, and various electronic devices.
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What are the main uses of a transformer?The main use of a transformer is voltage conversion. Transformers are used in power transmission systems to help transfer electricity from power plants to consumers. In addition, transformers are also used in electronic devices such as chargers, televisions, power adapters, etc., to adjust the voltage to meet the requirements of different devices.
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Do you have UL listed?Yes, our transformer has UL listed. We have exported to America many pad mounted transformer,substation transformer and HV.
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