42MVA 220kV Three Phase Oil Filled Transformer for Substation
The 42MVA 220kV Three Phase Oil Filled Transformer is specifically engineered for high-voltage transmission substations and utility grid applications. Featuring 99.9% electrolytic copper windings, advanced ONAN/ONAF cooling, and ±8×1.25% on-load tap changer, it ensures ultra-low no-load and load losses (SZ13 series available). Fully compliant with IEC 60076, GB/T 6451, and ANSI/IEEE standards, it successfully passes 460 kV lightning impulse, PD level below 10 pC, and induced test at 1.5Um/√3. Robust corrugated tank and conservator design provide excellent thermal and mechanical performance in extreme climates. Ideal for 220/33kV, 220/11kV, or 220/6.6kV step-down configurations. Vacuum oil processing and nitrogen blanketing guarantee long-term reliability and 35+ year service life. Trusted by national grids worldwide. Contact us for datasheet, pricing, and customization options.
- Primary Voltage Ratings 34.5-19.92/13.8-7.957/13.2-7.62/12.47-7.2, 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 transformer
- BIL 220kV
- Standards IEEE, ANSI, NEMA, IEC, CE
- Application transmission substations, step-down grid, backbone power grid
- Power Rating 42MVA
- 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
42MVA 220kV Three Phase Oil Filled Transformer for Substation
Technical Specifications
Accessories
| Rated Power | 42 MVA | |
| Rating Primary Voltage | 2.4 - 220kV | |
| 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 | |
| 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
42MVA 220kV Three Phase Oil Filled Transformer for Substation
The 42MVA 220kV Three Phase Oil Filled Transformer offers comprehensive customization to meet specific grid and substation requirements. Clients can choose copper or aluminum windings, ONAN, ONAF, or ODAF cooling methods, tap range of ±8×1.25%, ±10×1%, or special dual-ratio OLTC, and vector groups such as YNd11, Dyn11, or custom connections. Voltage combinations include 220±8×1.25%/33kV, 220/110/11kV tertiary, 220/35kV, or non-standard configurations. Impedance can be adjusted from 10% to 20%, with options for ultra-low-loss SZ13/SZ14 series, noise levels below 65 dB, or high-efficiency amorphous core designs.
Additional features include built-in current/voltage transformers, forced-air fan auto-control systems, online DGA and oil filtration interfaces, fiber-optic winding temperature monitoring, sudden pressure relay with trip/alarm, and full SCADA/RTU integration. Special adaptations cover high-altitude operation (>4000 m), seismic qualification up to 0.5g, extreme temperature (-50°C to +50°C), and heavy anti-corrosion C5-M/C5X painting. All customizations remain fully compliant with IEC 60076 and are supported by type/special test reports, ensuring seamless integration into any 220kV transmission project worldwide.
Packing and Shipping
42MVA 220kV Three Phase Oil Filled Transformer for Substation
To ensure the 42MVA 220kV Three Phase Oil Filled Transformer arrives at any 220kV substation worldwide without damage, we strictly execute the highest international heavy-transformer transportation standards (IEC 62271-207, IMO/ILO/UN packing codes, and CCS/DNV-GL guidelines).
Immediately after FAT approval and client sign-off, the transformer is vacuum-dehydrated to below 1 mbar and filled with ultra-dry nitrogen to 0.03–0.04 MPa positive pressure, effectively isolating insulation oil from air and moisture. All 220kV porcelain bushings, neutral bushings, conservator, detachable radiators, OLTC drive mechanism, cooling fans, Buchholz relay, and instruments are professionally dismantled, shock-proof packed in individual IPPC-fumigated plywood crates with multi-layer foam, desiccant bags, and dedicated shock/tilt indicators.
The main tank (gross weight approx. 85–95 tons) is welded onto a reinforced heavy-duty steel skid with 20 certified lashing points and four lifting lugs tested to 150% load. The body is then fully enclosed in a robust sealed wooden/steel composite crate using 30 mm marine plywood and 120×120 mm steel framing, double-wrapped with a waterproof membrane and aluminium-foil barrier. External surfaces carry clear bilingual markings (“42MVA 220kV Three Phase Oil Filled Transformer”), centre-of-gravity, lifting instructions, “No Hook”, “Keep Dry”, and IMO labels. Ten high-precision digital shock recorders and GPS real-time tilt monitors are installed for full traceability.
Transportation employs only licensed ultra-heavy haulage solutions: inland via 24–32 axle hydraulic modular trailers with route survey and escort; ocean freight as break-bulk under-deck or on DNV 2.7-1 certified 80ft heavy-lift flat-racks secured with Φ36 mm wire ropes and classification-society-approved lashing plans. Complete documentation—including detailed packing list, Form A/E origin certificate, fumigation certificate, nitrogen pressure report, insurance policy (110% value), and installation manual—is shipped together. These rigorous measures guarantee every 42MVA 220kV Three Phase Oil Filled Transformer reaches site in perfect condition, ready for immediate erection and commissioning.
Immediately after FAT approval and client sign-off, the transformer is vacuum-dehydrated to below 1 mbar and filled with ultra-dry nitrogen to 0.03–0.04 MPa positive pressure, effectively isolating insulation oil from air and moisture. All 220kV porcelain bushings, neutral bushings, conservator, detachable radiators, OLTC drive mechanism, cooling fans, Buchholz relay, and instruments are professionally dismantled, shock-proof packed in individual IPPC-fumigated plywood crates with multi-layer foam, desiccant bags, and dedicated shock/tilt indicators.
The main tank (gross weight approx. 85–95 tons) is welded onto a reinforced heavy-duty steel skid with 20 certified lashing points and four lifting lugs tested to 150% load. The body is then fully enclosed in a robust sealed wooden/steel composite crate using 30 mm marine plywood and 120×120 mm steel framing, double-wrapped with a waterproof membrane and aluminium-foil barrier. External surfaces carry clear bilingual markings (“42MVA 220kV Three Phase Oil Filled Transformer”), centre-of-gravity, lifting instructions, “No Hook”, “Keep Dry”, and IMO labels. Ten high-precision digital shock recorders and GPS real-time tilt monitors are installed for full traceability.
Transportation employs only licensed ultra-heavy haulage solutions: inland via 24–32 axle hydraulic modular trailers with route survey and escort; ocean freight as break-bulk under-deck or on DNV 2.7-1 certified 80ft heavy-lift flat-racks secured with Φ36 mm wire ropes and classification-society-approved lashing plans. Complete documentation—including detailed packing list, Form A/E origin certificate, fumigation certificate, nitrogen pressure report, insurance policy (110% value), and installation manual—is shipped together. These rigorous measures guarantee every 42MVA 220kV Three Phase Oil Filled Transformer reaches site in perfect condition, ready for immediate erection and commissioning.
32
32 years of industry experience
Manufacturer Test
42MVA 220kV Three Phase Oil Filled Transformer for Substation
Progress Test
The 42MVA 220kV Three Phase Oil Filled Transformer is subject to strict in-process Progress Tests at critical stages to guarantee exceptional quality:
- Active part completion: winding DC resistance at every tap, insulation resistance between HV-LV-core (PI ≥ 3.0), core earth current (<80 mA), and no-load loss preliminary measurement.
- Pre-vacuum stage: turns ratio & polarity at all taps (tolerance ≤ ±0.5%), vector group verification, zero-sequence impedance, and winding dielectric power factor.
- Post-processing stage (after 130°C vapor-phase drying and hot oil circulation): final insulation resistance (>10,000 MΩ), tanδ ≤ 0.0030 (20°C), partial discharge <10 pC at 1.5Um/√3, and oil dielectric strength >75 kV/2.5 mm.
- Final assembly: 24-hour oil static leakage test and 0.45 bar overpressure/vacuum tightness test for 24 hours each.
All test data are documented and submitted for client or third-party witness approval prior to Factory Acceptance Test, ensuring every 42MVA 220kV Three Phase Oil Filled Transformer meets the highest 220 kV transmission 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
Performed according to IEC 60076 series and client technical agreement, fully witnessed:
- Measurement of winding resistance at all OLTC positions (corrected to 75 °C)
- Ratio, polarity and phase displacement test at rated, +max and -max tap (tolerance ≤ ±0.5%)
- Vector group verification and magnetic balance test
- No-load loss & no-load current at 90 %, 100 %, 110 % rated voltage
- Load loss and impedance voltage at 75 °C, rated current on principal tap
- Zero-sequence impedance on all three phases
- Applied potential test (separate source AC withstand)
- Induced AC withstand test with PD monitoring (<10 pC at 1.5Um/√3, <5 pC at Um/√3)
- Lightning impulse full wave and chopped wave (950 kV peak on 220 kV side)
Complete FAT report with raw data and calibration certificates is signed off, ensuring the 42MVA 220kV Three Phase Oil Filled Transformer is 100 % qualified for immediate shipment and long-term reliable operation in 220 kV transmission networks.
Routine Test - Lightning Impulse
Purpose of Testing
The purpose of the lightning impulse test is to simulate the performance of the equipment when it is subjected to lightning or high voltage transient pulses, so as to evaluate its lightning resistance and insulation performance.
Testing Equipment
Lightning Impulse Tester. Usually a high voltage DC power supply, used to simulate lightning impulse waves. The voltage range can be adjusted according to the test standards and equipment requirements. Common voltages are 200 kV, 500 kV or higher. The specific voltage is customized according to customer requirements.
Pre-Test Preparation
Disconnect the device from the power supply and ensure that the device is properly grounded and discharged.
Check all terminals and connections to ensure they are secure and free of contamination.
Perform the test under suitable environmental conditions: relative humidity less than 75%, temperature between 20-30°C, no rain.
Check all terminals and connections to ensure they are secure and free of contamination.
Perform the test under suitable environmental conditions: relative humidity less than 75%, temperature between 20-30°C, no rain.
Test Progress
Connect the Test Instrument: Connect the lightning impulse test equipment to the high-voltage terminal or bushing of the device under test. Apply Test Voltage: According to the rated voltage of the equipment and the test standard, select the appropriate test voltage.
Measure and Record
Start the test and record the following parameters: Applied impulse voltage (kV)
Current waveform Impedance
Reaction voltage waveform
Ambient temperature and humidity during testing
Current waveform Impedance
Reaction voltage waveform
Ambient temperature and humidity during testing
Temperature Correction
The measured test data is temperature corrected according to the ambient temperature during the test, usually with a reference temperature of 20°C, to ensure the accuracy of the test results.
Repeat Testing (if necessary)
Repeated testing of different windings (high voltage, medium voltage, low voltage) or bushings under different test conditions ensures that the insulation performance of each part meets the standards.
Evaluation Criteria (Reference)
The lightning impulse test did not produce breakdown or irreversible damage: qualified
The voltage waveform meets the standard requirements, and the equipment does not have abnormal discharge or local breakdown: good
Obvious damage or non-standard waveform during the test: Further inspection or corrective measures are required
The voltage waveform meets the standard requirements, and the equipment does not have abnormal discharge or local breakdown: good
Obvious damage or non-standard waveform during the test: Further inspection or corrective measures are required
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
220kV transmission substations, step-down to 110kV/33kV grid, national backbone power grid interconnection, large-scale renewable energy integration (wind/solar farms), heavy industrial complexes (steel mills, petrochemical plants), urban high-voltage ring network supply, pumped-storage hydropower stations, railway traction substations (25kV feeding)
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
Product Packaging
Transformers Packaging (1)
Transformers Packaging (2)
Transformers Packaging (3)
Transformers Packaging (4)
Transformers Packaging (5)
Transformers Packaging (6)
Transformers Packaging (7)
Transformers Packaging (8)
Related Products
45kV 2500kVA Weatherproof & Oven-Proof Oil-Immersed Power Transformer
The 45kV 2500kVA Weatherproof & Oven-Proof Oil-Immersed Power Transformer is engineered for demanding outdoor applications requiring high durability, stable voltage transformation, and long-term operational reliability. Designed with premium cold-rolled silicon steel, high-conductivity copper windings, and a reinforced oil-immersed cooling system, the transformer ensures excellent thermal stability and resistance to overheating. Its oven-proof construction allows the unit to withstand high ambient temperatures, while the weatherproof enclosure provides protection against rain, dust, humidity, and corrosive environments. With advanced insulation, strong short-circuit endurance, and compatibility with both off-load and on-load tap changers, this 45kV outdoor transformer is ideal for substations, industrial facilities, renewable energy sites, and long-distance power distribution systems. Built in accordance with IEC 60076 standards, it delivers efficiency, reliability, and lifespan required for critical grid infrastructure.
1500kVA Three Phase Pad Mounted Transformer
NPC ELECTRIC's 1500kVA Three Phase Pad Mounted transformer is designed with high-quality silicon steel sheets and insulating oil, in compliance with international standards such as IEC and ANSI, ensuring efficient and stable operation. It is suitable for a variety of scenarios such as urban power distribution, residential areas, commercial parks and industrial facilities. Whether it is ring network power supply or radial power supply, it can be flexibly applied to help achieve efficient and intelligent power transmission and distribution solutions.
20kV Three-Phase Oil-Immersed Power Transformer 50-2500kVA Copper
The 20kV Three-Phase Oil-Immersed Power Transformer 50-2500kVA Copper adopts high-purity electrolytic copper windings, Class A insulation, and advanced ONAN cooling design. Available in energy-saving S11/S13/S20 series with no-load loss reduced by up to 40%. Fully sealed corrugated tank or conservator type effectively prevents oil aging and moisture ingress. It complies with IEC 60076, GB/T 1094, and can be equipped with ±5% or ±2×2.5% off-circuit tap changer. Low noise (<55 dB), strong short-circuit withstand capability, and overload capacity make it ideal for industrial parks, commercial buildings, and renewable energy projects. Vacuum oil filling and nitrogen sealing ensure insulation performance for over 30 years. Factory supports full third-party inspection (SGS/BV) and provides type test reports.
315kVA Oil Immersed Transformer
The 315kVA Oil Immersed Transformers are essential devices that convert electrical energy from one voltage level to another, enabling the efficient transmission and distribution of power across various systems. Oil-immersed transformers, in particular, have become industry favorites due to their superior cooling and insulation capabilities, which extend their lifespan and reduce maintenance requirements. The integration of renewable energy sources, such as wind and solar, requires transformers that can handle the variable output of these sources. 315kVA Oil Immersed Transformers are well-suited for this task due to their robustness and adaptability.
50kV 1000kVA Outdoor Three-Phase Oil-Immersed Power Transformer for Distribution
The 50kV 1000kVA Outdoor Three-Phase Oil-Immersed Power Transformer for Distribution is engineered to deliver high efficiency, stable voltage regulation, and long-term service reliability in medium-voltage distribution networks. Designed for outdoor installation, the transformer features a robust oil-immersed cooling system, high-grade silicon steel core, and pure copper windings to ensure excellent thermal performance and low-loss characteristics. Its rugged, weatherproof construction withstands harsh climates, ensuring continuous operation in industrial plants, utility grids, mining sites, and renewable energy distribution stations. With optimized insulation, superior dielectric strength, and advanced protection configurations, the transformer offers enhanced safety and reduced maintenance. This unit is ideal for step-down power distribution scenarios requiring consistent performance and dependable energy delivery.
50kVA Conventional Type Single Phase Pole Mounted Transformer
The 50kVA Conventional Type Single Phase pole Mounted transformer produced by NPC ELECTRIC has a rated capacity ranging from 10kVA to 333kVA, meeting the standards of ANSI/IEEE C57, IEC60076, etc. Its main function is to convert high-voltage power (such as 10kV, 11kV, etc.) into low-voltage power (such as 220V, 240V) through the transformer for use in homes, shops, industrial equipment, etc. It is suitable for residential areas, commercial areas, rural power grids, agricultural facilities and small industrial power supply.FAQ From Customers
-
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.
-
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.
-
Do you have UL listed?Yes, our transformer has UL listed. We have exported to America many pad mounted transformer,substation transformer and HV.
Welcome your inquiry
Honesty, Integrity, Frugality, Activeness and Passion