220kV 3-Phase Oil-Immersed Power Transformer – Reliable & Efficient
The 220kV 3-Phase Oil-Immersed Power Transformer is designed for high-capacity transmission and substation systems that demand long-term reliability and superior electrical efficiency. Built for modern power grids, it enables stable voltage transformation while minimizing operational losses over extended transmission distances. The oil-immersed insulation system provides excellent dielectric strength and efficient heat dissipation, supporting continuous operation under heavy electrical loads. Advanced core and winding design reduces noise and energy loss while improving voltage regulation accuracy. The robust mechanical structure enhances resistance to thermal stress and short-circuit forces, ensuring dependable performance in demanding grid environments. This transformer is ideal for utility substations, regional grid interconnections, and critical power infrastructure requiring efficient, safe, and stable high-voltage power delivery.
- Primary Voltage Ratings 220kV 230kV or Others
- Secondary Voltage Ratings 69/35/37/34.5/26.4./11/10.5/6.6/13.2 kV or others
- H.V. Tap Range ± 8×1.25% HV taps or others
- Type Oil-immersed power transformer
- BIL 900kV
- Standards IEEE, ANSI, IEC, GB
- Application national transmission grids, high-voltage substations, regional interconnection projects
- Power Rating 5000-250000kVA
- Certificate UL, ISO, CESI
- Cooling Method ONAN/ ONAF
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
220kV 3-Phase Oil-Immersed Power Transformer – Reliable & Efficient
Technical Specifications
Accessories
| Rated Power | 5000-250000kVA |
| Rating Primary Voltage | 220kV 230kV or Others |
| Secondary Voltage |
69/35/37/34.5/26.4/11/10.5/6.6/13.2 kV Customized |
| Frequency | 50/60Hz |
| Vector Group | Dyn11, YD11, YNd11 or anothers |
| Winding Material | Aluminum/Copper |
| Efficiency | As IEEE, CAS Std or Customized |
| Impedance Voltage | As IEC |
| Altitude | ≤1,000m or Customized |
| Enclosure material | Mid Steel |
| HV Bushing |
| LV Bushing |
| OLTC/NLTC |
| Lifting hook for complete transformer |
| Name plate |
| Oil temperature |
| Winding temperature |
| Radiators |
| Oil level |
| Pressure relief valve |
| CT |
Customization Optional
220kV 3-Phase Oil-Immersed Power Transformer – Reliable & Efficient
The 220kV 3-Phase Oil-Immersed Power Transformer can be extensively customized to meet specific grid planning and operational requirements. Electrical parameters such as rated voltage combinations, capacity range, impedance values, and insulation coordination can be precisely engineered to align with regional standards and network conditions. Winding configurations may be optimized for lower losses, improved thermal margins, or enhanced short-circuit withstand capability. Voltage regulation solutions, including off-circuit or on-load tap changers, can be configured with project-specific tap ranges and step resolutions to ensure stable system operation during load fluctuations. Structural and environmental customization options further enhance adaptability.
Transformer tanks can be designed for indoor or outdoor substations, with reinforced structures available for seismic zones or challenging transport routes. Surface protection systems may be selected to resist corrosion in coastal, industrial, or high-pollution environments. Cooling arrangements can be optimized according to ambient temperature, altitude, and load profile to maintain consistent thermal performance. Optional intelligent monitoring systems allow real-time tracking of oil temperature, winding temperature, pressure, and load conditions. Additional options include alternative insulating fluids, noise-reduction designs, customized paint colors, nameplates, documentation formats, and project-specific testing protocols. Each customization is supported by detailed engineering analysis to ensure compliance with international standards and long-term operational reliability.
Packing and Shipping
220kV 3-Phase Oil-Immersed Power Transformer – Reliable & Efficient
Packing and shipping of the 220kV oil-immersed power transformer are carefully planned to ensure safe transportation and preservation of performance. Before packing, the transformer undergoes final inspection and protective treatment. All openings are sealed, and sensitive components are protected against dust, moisture, and corrosion. Detachable accessories such as bushings, radiators, conservators, and control cabinets are removed when required and packed separately in reinforced crates with internal cushioning and moisture-resistant liners.
The transformer's main body is secured on a specially engineered transport base designed to evenly distribute weight and minimize mechanical stress. Shock-absorbing materials and rigid restraint systems are applied to protect against vibration, impact, and movement during transport. For long-distance or extended shipping periods, preservation measures such as oil protection procedures and desiccants are applied to maintain insulation integrity.
Transportation methods are selected based on transformer size, weight, route constraints, and destination conditions. Shipping options may include flat-rack containers, open-top containers, or break-bulk transport for oversized units. All packing materials comply with international export regulations, including ISPM-15 standards for wooden packaging. Clear handling instructions, lifting points, and center-of-gravity markings are provided to ensure safe loading and unloading.
Each shipment is accompanied by complete documentation, including packing lists, quality certificates, test reports, drawings, and operation manuals. Upon arrival, customers receive guidance for inspection, storage, and installation. Optional services such as on-site supervision, oil filling, commissioning assistance, and technical training can be provided to support smooth project execution.
The transformer's main body is secured on a specially engineered transport base designed to evenly distribute weight and minimize mechanical stress. Shock-absorbing materials and rigid restraint systems are applied to protect against vibration, impact, and movement during transport. For long-distance or extended shipping periods, preservation measures such as oil protection procedures and desiccants are applied to maintain insulation integrity.
Transportation methods are selected based on transformer size, weight, route constraints, and destination conditions. Shipping options may include flat-rack containers, open-top containers, or break-bulk transport for oversized units. All packing materials comply with international export regulations, including ISPM-15 standards for wooden packaging. Clear handling instructions, lifting points, and center-of-gravity markings are provided to ensure safe loading and unloading.
Each shipment is accompanied by complete documentation, including packing lists, quality certificates, test reports, drawings, and operation manuals. Upon arrival, customers receive guidance for inspection, storage, and installation. Optional services such as on-site supervision, oil filling, commissioning assistance, and technical training can be provided to support smooth project execution.
32
32 years of industry experience
Manufacturer Test
220kV 3-Phase Oil-Immersed Power Transformer – Reliable & Efficient
Progress test
Progress testing for the 220kV 3-phase oil-immersed power transformer is carried out through a structured inspection program at each critical manufacturing stage. Incoming materials, including magnetic steel, copper conductors, insulation components, and insulating oil, are verified against approved technical specifications. During core assembly, inspections focus on lamination stacking accuracy, clamping stability, and magnetic path continuity. Winding production is monitored for insulation thickness, conductor alignment, and dimensional accuracy.
Following winding completion, the active part undergoes controlled drying and vacuum processing to achieve specified moisture limits. Intermediate electrical checks, including winding resistance and turns ratio measurements, are conducted before tank assembly. Tank fabrication is inspected for welding quality, dimensional tolerance, and surface coating integrity. Prior to oil filling, oil tightness tests and internal cleanliness inspections are performed. All results are recorded to ensure traceability and manufacturing quality consistency.
Design Tests
All transformers will be tested after finishing the production test items as follows:
♦ Leak testing with pressure for liquid-immersed transformers
♦ Test of transformer oil
♦ Measurement of voltage ratio and check of phase displacement
♦ Measurement of winding DC resistance
♦ Measurement of d. c. Insulation resistance between each winding to earth, and check of the core and frame insulation
♦ Capacitive bushing test
♦ Measurement of dissipation factor (tan δ) of the insulation system capacitances, and determination of capacitances windings-to-earth
♦ Measurement of no-load loss and current at 90%,100%,110% of rated voltage
♦ Operation test on on-load tap-changer
♦ Measurement of short-circuit impedance and load loss
♦ Lightning impulse test
♦ Induced-voltage test with partial discharge measurement
♦ Auxiliary wiring check
♦ Current transformer test
♦ Frequency response analysis test
Transformer Factory Acceptance Test
The Factory Acceptance Test (FAT) confirms that the 220kV 3-phase power transformer meets all technical and contractual requirements. Routine electrical tests include winding resistance measurement, voltage ratio verification, vector group confirmation, polarity checks, and insulation resistance testing. Dielectric tests, such as applied voltage and induced voltage withstand tests, validate insulation strength and safety margins.
Performance testing evaluates no-load losses, load losses, impedance voltage, and temperature rise to verify efficiency and thermal stability. Partial discharge testing assesses insulation condition, while impulse tests confirm resistance to transient overvoltages. Mechanical inspections cover oil tightness, tank pressure resistance, cooling system operation, and accessory functionality. All FAT results are documented for customer approval before shipment.
Routine Test - Insulation Power Factor
Purpose of Testing
The purpose of winding resistance testing is to detect the continuity and connection quality of the internal conductors of the motor or transformer windings, and to promptly detect potential faults such as open circuits, poor contact or local heating.
Testing Equipment
Winding resistance tester (e.g. OMICRON, DV Power, Raytech, Megger, ISA, etc.)
Test voltage source (commonly used are 6V, 10V, 20V, 40V or 100V, depending on the equipment model or customer requirements)
Temperature and humidity meter (used to record the ambient temperature and humidity during the test)
Test voltage source (commonly used are 6V, 10V, 20V, 40V or 100V, depending on the equipment model or customer requirements)
Temperature and humidity meter (used to record the ambient temperature and humidity during the test)
Pre-Test Preparation
Check if the instrument has been calibrated to ensure the test accuracy.
Disconnect the electrical connection between the test cable and the equipment to ensure that there is no external current or voltage interference.
Select a suitable voltage range for testing and set the test voltage according to the equipment requirements.
Disconnect the electrical connection between the test cable and the equipment to ensure that there is no external current or voltage interference.
Select a suitable voltage range for testing and set the test voltage according to the equipment requirements.
Test Progress
Connect the Test Instrument:
Connect the test equipment to the winding terminals of the device under test, making sure the connections are secure and properly grounded to avoid measurement errors.
Apply Test Voltage:
Select the appropriate test current according to the equipment specifications (such as test current for low-voltage windings, single-phase or three-phase windings).
Connect the test equipment to the winding terminals of the device under test, making sure the connections are secure and properly grounded to avoid measurement errors.
Apply Test Voltage:
Select the appropriate test current according to the equipment specifications (such as test current for low-voltage windings, single-phase or three-phase windings).
Test Standard
IEC 60076 Oil-immersed power transformers
Temperature Correction
The measured winding resistance values are converted to a reference temperature (usually 20°C) based on a temperature correction formula to allow accurate evaluation and comparison.
Repeat Testing (if necessary)
Test the different windings (high voltage, medium voltage, low voltage) separately and make sure to record the resistance value of each winding.
Evaluation Criteria (Reference)
Resistance deviation is less than 5% (normal)
Resistance deviation is between 5% and 10% (warning)
Resistance deviation exceeds 10% (further inspection or corrective action is required)
Resistance deviation is between 5% and 10% (warning)
Resistance deviation exceeds 10% (further inspection or corrective action is required)
Measure and Record
Start the test and record the following parameters:
Winding resistance (usually expressed in units of "Ω")
Test current (A)
Test voltage (V)
Temperature (record the winding temperature before and after the test)
Winding resistance (usually expressed in units of "Ω")
Test current (A)
Test voltage (V)
Temperature (record the winding temperature before and after the test)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
This transformer is widely used in national transmission grids, high-voltage substations, regional interconnection projects, and critical infrastructure requiring reliable and efficient three-phase high-voltage power transmission.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
Product Packaging
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Transformers Packaging (2)
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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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