260 kV 20MVA 28 MVA Substation Power Transformer
The robust 260 kV 20/28 MVA substation power transformer, engineered for high-voltage applications in modern electrical grids. This oil-immersed unit features dual capacity ratings for flexible operation under varying loads, ensuring efficient power distribution and voltage step-down in utility substations. With advanced insulation systems and low-loss core materials, it minimizes energy dissipation while handling peak demands reliably. Ideal for integrating renewable energy sources or industrial power systems, this transformer complies with IEC 60076 standards, offering superior performance in harsh environments. Its compact design facilitates easy installation, making it a top choice for upgrading aging infrastructure or expanding grid capacity.
- Primary Voltage Ratings 220kV 230kV 260kV
- 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 regional distribution, supporting grid stability in urban power networks
- Power Rating 20MVA 28 MVA
- 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
260 kV 20MVA 28 MVA Substation Power Transformer
Technical Specifications
Accessories
| Rated Power | 20MVA 28 MVA |
| Rating Primary Voltage | 220kV 230kV 260kV |
| 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
260 kV 20MVA 28 MVA Substation Power Transformer
Tailor your 260 kV 20/28 MVA substation power transformer to meet specific project demands with a range of customizable features. Voltage configurations can be adjusted for primary and secondary windings, including options for dual-voltage setups or specialized tap changers to handle fluctuating grid conditions. Cooling systems offer choices between ONAN (oil natural air natural) and ONAF (oil natural air forced) for enhanced thermal management in high-load scenarios. Impedance levels can be fine-tuned from standard 8-12% to custom values for better fault current control and system stability. Enclosure types include weatherproof IP-rated housings or explosion-proof designs for hazardous areas, while accessories like Buchholz relays, pressure relief devices, and digital monitoring interfaces integrate seamlessly for smart grid compatibility. Material selections, such as silicon steel cores for reduced no-load losses or copper windings for superior conductivity, ensure longevity and efficiency in diverse climates.
Further customization extends to vector groups (e.g., Dyn11 or YNd1) for phase shift requirements in parallel operations, and bushing arrangements compatible with GIS or AIS substations. Noise reduction packages with sound-dampening enclosures meet urban installation standards, while eco-friendly options like biodegradable ester fluids replace traditional mineral oil for environmental compliance. Size and weight optimizations allow for skid-mounted or trailer-compatible designs, facilitating transport to remote sites. Advanced testing protocols can be incorporated pre-delivery, including partial discharge measurements or impulse testing beyond routine checks. These bespoke features not only optimize performance but also reduce operational costs, making this transformer adaptable for solar farms, wind integration, or data center backups.
Packing and Shipping
260 kV 20MVA 28 MVA Substation Power Transformer
Secure packaging is essential for transporting high-voltage 260 kV 20/28 MVA substation power transformers to prevent damage from vibrations or impacts. Units are first drained of oil if required, then encased in moisture-resistant vapor corrosion inhibitor (VCI) bags to guard against humidity during transit. Wooden crates reinforced with steel frames provide structural support, with internal cushioning using foam pads and shock-absorbing materials to stabilize the core and windings. External markings include "Fragile - High Voltage Equipment" labels, handling instructions, and center-of-gravity indicators for safe lifting by cranes or forklifts. Compliance with international standards like ASTM D4169 ensures packages withstand drop, vibration, and compression tests.
Shipping options vary based on destination and urgency, with overland transport via specialized flatbed trucks equipped with air-ride suspension to minimize road shocks. For international deliveries, containers are customized with reinforced floors and tie-down points, often using 40-foot high-cube units for oversized transformers. GPS tracking and impact recorders monitor the journey in real-time, alerting to any deviations. Insurance covers full value against transit risks, and pre-shipment inspections verify secure fastening.
Coordination with logistics partners ensures seamless customs clearance, especially for heavy-lift cargo requiring permits for oversized loads. Air freight is viable for urgent smaller units, though sea freight via roll-on/roll-off (RoRo) vessels is preferred for cost-efficiency on long hauls. On-site unloading involves heavy machinery like gantry cranes, with nitrogen purging to maintain internal dryness during extended voyages.
Post-shipping protocols include immediate visual checks upon arrival and oil refilling if drained, followed by basic electrical tests to confirm integrity. Sustainable practices incorporate recyclable packing materials, reducing environmental impact while adhering to ISO 14001 guidelines. Delivery timelines typically range from 4-12 weeks, depending on route and customs, with dedicated project managers overseeing the process for timely substation integration.
Shipping options vary based on destination and urgency, with overland transport via specialized flatbed trucks equipped with air-ride suspension to minimize road shocks. For international deliveries, containers are customized with reinforced floors and tie-down points, often using 40-foot high-cube units for oversized transformers. GPS tracking and impact recorders monitor the journey in real-time, alerting to any deviations. Insurance covers full value against transit risks, and pre-shipment inspections verify secure fastening.
Coordination with logistics partners ensures seamless customs clearance, especially for heavy-lift cargo requiring permits for oversized loads. Air freight is viable for urgent smaller units, though sea freight via roll-on/roll-off (RoRo) vessels is preferred for cost-efficiency on long hauls. On-site unloading involves heavy machinery like gantry cranes, with nitrogen purging to maintain internal dryness during extended voyages.
Post-shipping protocols include immediate visual checks upon arrival and oil refilling if drained, followed by basic electrical tests to confirm integrity. Sustainable practices incorporate recyclable packing materials, reducing environmental impact while adhering to ISO 14001 guidelines. Delivery timelines typically range from 4-12 weeks, depending on route and customs, with dedicated project managers overseeing the process for timely substation integration.
32
32 years of industry experience
Manufacturer Test
260 kV 20MVA 28 MVA Substation Power Transformer
Progress test
In the production phase of the 260 kV 20/28 MVA substation power transformer, progress testing emphasizes material and assembly validation. Silicon steel core cutting is tested for burr-free edges and low core loss via Epstein frame methods. Coil winding advancement includes impedance testing per stage to maintain design specifications. Vacuum drying processes are monitored with moisture content analysis using Karl Fischer titration, preventing insulation degradation. Bushing installation undergoes dielectric strength tests to verify seal integrity. Final active part assembly features alignment checks with laser tools for precise fitting. Adhering to ANSI/IEEE protocols, these tests facilitate iterative improvements, ensuring the transformer meets substation demands for durability and efficiency.
Design Tests
All transformers will be tested after finishing the production test items as below:
♦ 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
Factory acceptance tests for the 260 kV 20/28 MVA substation power transformer encompass routine and type evaluations per IEC 60076. Visual inspections confirm enclosure integrity and accessory mounting. Winding resistance tests measure DC values across taps, verifying material quality. Insulation resistance assessments use megohmmeter at 5 kV to detect moisture or contamination. Turns ratio tests apply low voltage to confirm winding proportions. No-load loss evaluations energize the core at rated voltage, calculating efficiency. Load loss and impedance tests simulate full current conditions. Partial discharge measurements ensure minimal internal arcing. Oil dielectric strength and dissolved gas analysis verify insulation fluid purity. These comprehensive procedures guarantee compliance and performance before shipment.
Routine Test - Induced Voltage
Purpose of Testing
The purpose of the Induced Voltage test is to simulate the electrical stress that the equipment may encounter under actual working conditions by applying an induced voltage, thereby evaluating the tolerance and stability of the equipment's insulation system. This test helps to detect the insulation performance of the equipment under high voltage conditions and ensure its safety and reliability in operation.
Testing Equipment
Induced Voltage Tester (e.g. OMICRON, Megger, HioKI, etc.)
AC voltage source, commonly 2 kV, 5 kV, 10 kV, or customized according to test requirements.
Environmental thermometer and hygrometer, used to record the temperature and humidity of the environment for appropriate test evaluation.
AC voltage source, commonly 2 kV, 5 kV, 10 kV, or customized according to test requirements.
Environmental thermometer and hygrometer, used to record the temperature and humidity of the environment for appropriate test evaluation.
Pre-Test Preparation
Disconnect all relevant power supplies and ensure that the equipment is properly grounded and discharged.
Check the connection wires and terminals to ensure they are secure and free of contamination.
Test under suitable environmental conditions: relative humidity below 75%, no rain (recommended temperature: 20-30°C).
Check the connection wires and terminals to ensure they are secure and free of contamination.
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 equipment to the appropriate terminals or bushings of the device under test, ensuring that the connections are secure and properly grounded.
Apply Test Voltage:
Select the appropriate induction voltage according to the rated voltage and standard of the equipment.
Connect the test equipment to the appropriate terminals or bushings of the device under test, ensuring that the connections are secure and properly grounded.
Apply Test Voltage:
Select the appropriate induction voltage according to the rated voltage and standard of the equipment.
Test Standard
IEC 60076 Oil-immersed power transformers
Measure and Record
Start the test and record the following parameters:
Induced Voltage
Applied Current
Voltage peak, stability and waveform (waveform analysis)
Any abnormal current or voltage changes during the measurement process.
Induced Voltage
Applied Current
Voltage peak, stability and waveform (waveform analysis)
Any abnormal current or voltage changes during the measurement process.
Temperature Correction
The measured induced voltage data is corrected to the reference temperature (usually 20°C) to ensure the accuracy of the test results.
Repeat Testing (if necessary)
If necessary, test different windings (HV, MV, LV) and bushings separately and compare the results at different test points.
Evaluation Criteria (Reference)
Inductive voltage ≤ 1% (Excellent): normally and meets safety standards.
1% < Inductive voltage ≤ 3% (Good): still within acceptable range.
Inductive voltage > 3% : faulty or not meet safety requirements and requires further analysis and repair.
1% < Inductive voltage ≤ 3% (Good): still within acceptable range.
Inductive voltage > 3% : faulty or not meet safety requirements and requires further analysis and repair.
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
In utility transmission substations, the 260 kV 20/28 MVA power transformer steps down voltage for regional distribution, supporting grid stability in urban power networks with renewable integration.
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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