3000kVA Oil Immersed Transformer
The 3000kVA Oil Immersed Transformer is a high-capacity three-phase power distribution transformer engineered for heavy-duty medium- to high-voltage step-down. Premium high-permeability cold-rolled grain-oriented silicon steel core (S13/S18 series level) significantly reduces no-load losses (typically 3500–4800W), while high-conductivity copper windings and superior mineral or ester insulating oil (IEC 60296/IEC 61099 compliant, dielectric >60kV/2.5mm) achieve low load losses (around 22–28kW at 75°C), ONAN/ONAF cooling capability for sustained overloads (up to 150–180% short-term), noise levels <65dB, and peak efficiency >99%. Conforming to energy efficiency regulations, this transformer delivers substantial energy savings, reduced transmission losses, and dependable performance in industrial, utility, and renewable applications.
- 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 Temporary Power Supply Systems, Utilities
- Power Rating 3000kVA
- 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
3000kVA Oil Immersed Transformer
Technical Specifications
Accessories
| Rated Power | 3000kVA | |
| 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 | 1930 kg | |
| Total Weight | 7100 kg | |
| Outline Dimensions（L×W×H）in. | 2520 × 2000 × 2720（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
3000kVA Oil Immersed Transformer
The 3000kVA oil immersed transformer offers comprehensive customization to match demanding grid, industrial, and renewable project specifications. Rated capacities are fixed at 3000kVA with primary voltages selectable from 11kV to 35kV (including 22kV, 33kV, 34.5kV options) and secondary voltages configurable to 0.4kV, 0.69kV, 6.3kV, 10kV, 11kV, or dual/multi-winding arrangements. Voltage regulation is available via multi-position off-circuit tap changers (±5% to ±10%) for fixed networks or advanced on-load tap changers (OLTC, 17–33 steps with motor drive) for automatic control under fluctuating loads such as renewable integration or heavy industrial cycles. Core construction choices include high-grade grain-oriented silicon steel for standard low losses or amorphous alloy for up to 70% no-load loss reduction, optimizing energy efficiency. Winding materials provide premium copper for maximum conductivity, thermal endurance, and fault tolerance or aluminum for cost-effective high-power designs.
Customization extends to cooling configurations (ONAN base with ONAF forced air/fans or pumps for extreme ambients -40°C to +55°C or prolonged overloads), insulating fluids (conventional mineral, natural/synthetic esters for fire safety, biodegradability, and IEC 61099 compliance), and tank designs featuring conservator with breather, full hermetic sealing, C5-M marine-grade anti-corrosion coatings, seismic reinforcement, or enhanced IP protection for polluted/coastal installations. Accessories include online DGA monitoring, fiber-optic hot-spot sensors, SCADA/RTU interfaces, surge arresters, gas relays, and smart metering systems. Impedance (6–10%), vector groups (Dyn11, YNd1, etc.), BIL levels (up to 200kV), frequency (50/60Hz), noise reduction enclosures, and full adherence to IEC 60076, GB1094, ANSI/IEEE, or local efficiency classes are adjustable. Our engineering team collaborates closely to deliver optimized solutions for primary substations, wind/solar farms, mining operations, petrochemical plants, or large commercial facilities, emphasizing peak efficiency, fault resilience, minimal lifecycle costs, and seamless system integration.
Packing and Shipping
3000kVA Oil Immersed Transformer
Transporting the 3000kVA oil immersed transformer requires meticulous preparation to preserve core/winding alignment, insulation quality, and oil system integrity throughout global logistics. Pre-packing inspections include tank hydrostatic/leak tests (1.5x rated pressure), bushing and terminal torque checks, oil dielectric/acidity sampling (>60kV/2.5mm, <20ppm water), and protective relay/temperature device functionality verification. Units typically ship with conservator oil-filled and nitrogen blanketed (0.02–0.06MPa positive pressure) to prevent oxidation and moisture; larger or weight-restricted shipments partially drain oil into dedicated sealed ISO-grade tanks/drums, supplied with vacuum degassing equipment and matching high-purity oil for on-site reprocessing per IEC standards.
Detached components are individually protected: radiators crated with anti-vibration foam and bracing, high-voltage bushings (RIP/porcelain) in custom shock-mounted enclosures, OLTC mechanisms locked and sealed, and control cubicles wrapped with desiccants. The main transformer body is secured to heavy steel skids or ISPM-15 compliant reinforced wooden/steel cradles featuring engineered blocking, lateral restraints, and impact-absorbing systems rated for 5–6g forces typical in multimodal transport. Packaging incorporates multi-layer weatherproof tarpaulins, volatile corrosion inhibitors (VCI), humidity/temperature recorders, and digital shock/tilt loggers for full handling traceability.
Ocean freight—the primary mode for export—utilizes flat-rack, open-top, or heavy-lift vessels with IMO-compliant lashing, salt-mist protective barriers, and full shrouding; inland road/rail transport employs specialized low-loader trailers with hydraulic suspension, weight-distributed cradles, and marked lifting lugs. Complete export documentation package includes commercial invoices, detailed packing lists, certificates of origin/conformity, routine/type test reports, dimensional/lifting drawings, oil safety data sheets, installation manuals, and HS code declarations (8504.22/8504.23 for power transformers in this capacity range).
We manage full-scope logistics coordination from factory to final destination, offering FOB/CIF/door delivery, customs clearance support, marine insurance, and value-added services such as third-party pre-shipment inspections, professional crane offloading supervision, on-site oil filtration/processing, transformer erection guidance, and commissioning assistance. This integrated process minimizes transit risks, maintains factory-calibrated performance, complies with international regulations, and ensures timely, damage-free delivery for utility, industrial, and renewable energy clients worldwide.
Detached components are individually protected: radiators crated with anti-vibration foam and bracing, high-voltage bushings (RIP/porcelain) in custom shock-mounted enclosures, OLTC mechanisms locked and sealed, and control cubicles wrapped with desiccants. The main transformer body is secured to heavy steel skids or ISPM-15 compliant reinforced wooden/steel cradles featuring engineered blocking, lateral restraints, and impact-absorbing systems rated for 5–6g forces typical in multimodal transport. Packaging incorporates multi-layer weatherproof tarpaulins, volatile corrosion inhibitors (VCI), humidity/temperature recorders, and digital shock/tilt loggers for full handling traceability.
Ocean freight—the primary mode for export—utilizes flat-rack, open-top, or heavy-lift vessels with IMO-compliant lashing, salt-mist protective barriers, and full shrouding; inland road/rail transport employs specialized low-loader trailers with hydraulic suspension, weight-distributed cradles, and marked lifting lugs. Complete export documentation package includes commercial invoices, detailed packing lists, certificates of origin/conformity, routine/type test reports, dimensional/lifting drawings, oil safety data sheets, installation manuals, and HS code declarations (8504.22/8504.23 for power transformers in this capacity range).
We manage full-scope logistics coordination from factory to final destination, offering FOB/CIF/door delivery, customs clearance support, marine insurance, and value-added services such as third-party pre-shipment inspections, professional crane offloading supervision, on-site oil filtration/processing, transformer erection guidance, and commissioning assistance. This integrated process minimizes transit risks, maintains factory-calibrated performance, complies with international regulations, and ensures timely, damage-free delivery for utility, industrial, and renewable energy clients worldwide.
32
32 years of industry experience
Manufacturer Test
3000kVA Oil Immersed Transformer
Progress Test
Progress testing for the 3000kVA oil immersed transformer begins with high-permeability silicon steel lamination inspection for thickness consistency insulation coating integrity magnetic flux density and burr-free edges via Epstein frame testing to secure ultra-low core losses then core stacking progress verifies multi-step mitered joints precise yoke clamping torque flux shielding and vibration suppression measures. Winding fabrication progress monitors oxygen-free copper conductor purity insulation paper/enamel buildup automated winding tension control turn precision and high-voltage inter-turn dielectric testing post-winding. Core-coil assembly progress confirms radial axial clearances critical barrier placement end-insulation compression and short-circuit force withstand bracing structures. Tank production progress evaluates multi-layer weld seam NDT radiography hydrostatic overpressure holds surface preparation multi-coat epoxy/polyurethane painting thickness and corrosion resistance validation pre-integration progress audits bushing radiator conservator alignment accessory mounting and initial vacuum pressure cycle simulations to identify early assembly issues ensuring smooth progression to detailed qualification phases.
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)
♦ Polarity, 1-Ph / Phase Relation, 3-Ph (Rated Voltage)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Induced Voltage
♦ Lightning Impulse
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)
Transformer Factory Acceptance Test
Load loss impedance voltage efficiency determination for the 3000kVA oil immersed transformer shorts secondary applies reduced primary voltage computes copper losses percentage impedance (6–10%) total losses at 75°C and regulation characteristics for overload assessment. Oil routine verifies dielectric strength (>60kV/2.5mm) moisture (<20ppm) acidity DGA baseline zero fault gases. Thermal indicators confirm top-oil winding temperature rise limits (<60K/<65K) through short-duration heat run simulation. Functional trials activate pressure relief devices Buchholz sudden pressure relays, temperature alarms OLTC full-cycle operation and sound power level (<65dB). Structural validation includes tank overpressure endurance, leak-free integrity bushing flashover margins wiring continuity. Detailed FAT reports with metrology-traceable certificates optional customer third-party witnessing, certify IEC 60076 GB1094 IEEE full compliance routine special test endorsement prior to shipment clearance.
Routine Test - No Load Loss Test
Purpose of Testing
The purpose of No Load Loss Test is to measure the power loss of the equipment when it is not loaded to evaluate the iron loss and other core losses. This test can help understand the energy efficiency of the equipment and help determine the performance of the transformer or motor when it is running at no load.
Testing Equipment
No Load Loss tester (e.g. OMICRON, Megger, Schneider Electric, etc.)
Voltage source (usually 230V, 400V or customized according to customer requirements to adapt to different equipment)
Power analyzer (used to measure power loss and efficiency)
Ammeter and voltmeter
Temperature and humidity meter
Voltage source (usually 230V, 400V or customized according to customer requirements to adapt to different equipment)
Power analyzer (used to measure power loss and efficiency)
Ammeter and voltmeter
Temperature and humidity meter
Pre-Test Preparation
Disconnect the power supply of the device and ensure that the device is properly grounded and discharged to ensure safe operation.
Please ensure that the test is carried out in a suitable environment with a relative humidity of less than 75% and avoid rainy days or extreme weather (recommended temperature range: 20-30°C).
Please ensure that the test is carried out in a suitable environment with a relative humidity of less than 75% and avoid rainy days or extreme weather (recommended temperature range: 20-30°C).
Test Progress
Connect the Test Instrument:
Connect the test equipment to the high voltage side of the transformer, making sure the wiring is correct and the equipment is grounded.
Apply Test Voltage:
Usually it is 110% of the rated voltage, for example, if the rated voltage of the transformer is 33 KV, apply 36.3 KV (110%).
Connect the test equipment to the high voltage side of the transformer, making sure the wiring is correct and the equipment is grounded.
Apply Test Voltage:
Usually it is 110% of the rated voltage, for example, if the rated voltage of the transformer is 33 KV, apply 36.3 KV (110%).
Measure and Record
Start the test and record the following parameters:
No Load Current
No Load Loss
Power Factor
Current
Voltage
Temperature and Humidity
No Load Current
No Load Loss
Power Factor
Current
Voltage
Temperature and Humidity
Temperature Correction
The power loss of the test results is corrected to a reference temperature (usually 20°C) to ensure an accurate evaluation.
Repeat Testing (if necessary)
Test at different rated voltages, especially when the transformer has multiple capacity levels, and perform no-load loss tests for each capacity level separately.
Evaluation Criteria (Reference)
No-load loss ≤ 0.2% rated power (excellent)
No-load loss < 0.2% ≤ 0.5% rated power (good)
No-load loss > 0.5% rated power (further inspection or corrective action required)
No-load loss < 0.2% ≤ 0.5% rated power (good)
No-load loss > 0.5% rated power (further inspection or corrective action required)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
It is suitable for various combined scenarios such as heavy-load power supply in large industrial plants and mines, voltage reduction in regional substations, voltage boosting in wind and solar power plants, power systems in ports and wharves, load centers in metallurgy and chemical industries, high-load power supply in data centers, and railway electrification hubs, achieving efficient medium-high voltage conversion and stable operation with low loss at 3000kVA.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
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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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