37kV 10000kVA(10MVA) Three Phase Duplex Winding Oil Immersed Power Transformer
The 37kV 10000kVA (10MVA) Three Phase Duplex Winding Oil Immersed Power Transformer is designed for high-reliability medium-voltage distribution and industrial applications. Featuring 99.95% electrolytic copper duplex windings, advanced ONAN/ONAF cooling, and ±8×1.25% on-load tap changer (optional), it delivers ultra-low no-load and load losses (S11/S13 series). Fully compliant with IEC 60076, GB/T 1094, and ANSI/IEEE standards, it withstands 170–200 kV lightning impulse and PD <10 pC. Corrugated tank or detachable radiator design ensures excellent heat dissipation and mechanical strength. Standard voltages 37±8×1.25%/11kV, 37/6.3kV or custom. Vacuum oil processing and nitrogen sealing guarantee 30+ years service life with minimal maintenance. Trusted by utilities, EPCs, and heavy industries worldwide.
- Primary Voltage Ratings 35kV, 34.5kV, 33kV, 46kV or others
- Secondary Voltage Ratings 13.8kV 6kV 10kV or others
- H.V. Tap Range ±8×1.25% or others
- Type Oil-immersed power transformer
- BIL 37kV
- Standards IEEE, ANSI, NEMA, IEC, CE
- Application industrial substations, steel & cement plants, oil refineries, mining operations
- Power Rating 10000kVA
- Certificate UL, CESI, IEEE
- Cooling Method ONAN/ONAF
- Oil Mineral Oil or FR3
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
37kV 10000kVA(10MVA) Three Phase Duplex Winding Oil Immersed Power Transformer
Technical Specifications
Accessories
| Rated Power | 10000kVA | |
| Rating Primary Voltage | 37 kV | |
| Secondary Voltage |
6.6kV 10kV 13.8kV 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 | |
| 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
37kV 10000kVA(10MVA) Three Phase Duplex Winding Oil Immersed Power Transformer
Customers can specify capacity 8000–12500kVA, full copper or copper-aluminum hybrid windings, S11/S13/S20 low-loss series, voltage ratios 37±8×1.25%/11kV, 37/13.8kV, 37/6.9kV, or tertiary winding options. Tap changer includes off-circuit ±5% or on-load ±8×1.25%/±10×1%. Vector group Dyn11, YNd11, or custom. Cooling ONAN, ONAF with auto-control fans, or forced oil circulation.
Additional options: built-in CT/PT, gas relay with alarm/trip, pressure relief valve, winding/oil temperature monitoring with 4–20 mA & fiber optic, online oil regeneration system, IP55 protective housing, high-altitude (>3000 m) compensation, seismic design 0.4g, low-noise version (<60 dB), and SCADA-ready RTU interface. All customizations maintain IEC 60076 compliance with type/special test reports available.
Packing and Shipping
37kV 10000kVA(10MVA) Three Phase Duplex Winding Oil Immersed Power Transformer
fter FAT, the transformer is vacuum-dehydrated and filled with dry nitrogen to 0.03 MPa positive pressure to prevent oil contamination during transit.
All 37kV bushings, conservator, radiators, OLTC diverter, cooling fans, and instruments are dismantled and packed in separate IPPC-fumigated wooden crates with high-density foam and desiccant. The main tank (~45–52 tons) is welded onto a heavy-duty steel skid, fully enclosed in a reinforced marine-plywood crate with steel framing and double waterproof wrapping. Clear markings “37kV 10000kVA Three Phase Duplex Winding Oil Immersed Power Transformer”, lifting points, and shock indicators are applied.
Transport uses hydraulic modular trailers inland and DNV-certified 40ft flat-rack or break-bulk under-deck for sea freight, secured with Φ28 mm wire ropes and classification-society-approved lashing. Eight shock recorders monitor impact and tilt.
Full documentation (packing list, fumigation & origin certificates, nitrogen report, 110% insurance) accompanies every shipment, ensuring safe, damage-free global delivery and immediate site readiness.
All 37kV bushings, conservator, radiators, OLTC diverter, cooling fans, and instruments are dismantled and packed in separate IPPC-fumigated wooden crates with high-density foam and desiccant. The main tank (~45–52 tons) is welded onto a heavy-duty steel skid, fully enclosed in a reinforced marine-plywood crate with steel framing and double waterproof wrapping. Clear markings “37kV 10000kVA Three Phase Duplex Winding Oil Immersed Power Transformer”, lifting points, and shock indicators are applied.
Transport uses hydraulic modular trailers inland and DNV-certified 40ft flat-rack or break-bulk under-deck for sea freight, secured with Φ28 mm wire ropes and classification-society-approved lashing. Eight shock recorders monitor impact and tilt.
Full documentation (packing list, fumigation & origin certificates, nitrogen report, 110% insurance) accompanies every shipment, ensuring safe, damage-free global delivery and immediate site readiness.
32
32 years of industry experience
Manufacturer Test
37kV 10000kVA(10MVA) Three Phase Duplex Winding Oil Immersed Power Transformer
Progress Test
Throughout manufacturing, the 37kV 10MVA transformer undergoes rigorous, client-witnessable Progress Tests at every critical stage to ensure zero defects before final FAT.
Stage 1 – Core & Coil Assembly
- Winding DC resistance measurement on all taps (HV & LV duplex windings)
- Insulation resistance between HV-LV-core-tertiary and ground (PI ≥ 2.5 at 130 °C after drying)
- Core grounding current (<100 mA) and preliminary no-load loss verification
- Turns ratio check on random coils and magnetic balance test
Stage 2 – Before Tanking
- Voltage ratio at principal and extreme taps (deviation ≤ ±0.5 %)
- Vector group confirmation (typically Dyn11 or YNd11) and polarity
- Zero-sequence impedance and winding power frequency withstand pre-test
All raw data, charts and photographs are compiled into an official Progress Test Report and submitted for client or third-party approval before proceeding to Factory Acceptance Test, fully guaranteeing every 37kV 10000kVA transformer meets the highest quality and reliability standards.
Design Tests
All transformer will be test after finished the production, test items as below:
♦ 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
Conducted per IEC 60076 with full client/third-party witness: winding resistance at all taps, ratio & polarity at extreme taps (≤ ±0.5%), vector group Dyn11/YNd11, no-load loss/current at 90–110% voltage, load loss & impedance at 75 °C, separate-source & induced withstand with PD <10 pC, lightning impulse 170–200 kV peak, insulation resistance/PI (≥ 2.5)/tanδ, oil test ≥ 70 kV, OLTC 10 full-load + 50 auxiliary cycles, cooling & protection function, sound level, final inspection. Signed protocol guarantees 100% readiness.
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
Ideal for 35–37kV industrial substations, steel & cement plants, oil refineries, mining operations, large commercial complexes, data centers, wind/solar farm grid connection, and urban ring-main networks requiring reliable 11kV/6.3kV step-down supply.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
Product Packaging
Transformers Packaging (1)
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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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