2500kVA Three Phase Pad Mounted Transformer
NPC ELECTRIC's 2500kVA Three Phase Pad Mounted Transformer is a high-performance, oil-immersed distribution transformer engineered for reliable outdoor installation on concrete pads. Compliant with ANSI/IEEE C57, DOE 2016 efficiency standards, and IEC guidelines, this 2.5 MVA unit delivers superior energy efficiency, low losses, and robust durability in demanding utility and industrial environments. Featuring a fully sealed, tamper-resistant enclosure with dead-front or live-front design options, it ensures maximum safety, minimal maintenance, and aesthetic integration in urban settings.
- Primary Voltage Ratings 34.5-19.92/13.8-7.957/13.2-7.62/12.47-7.2, 24.94, 26.25, 33 or others
- Secondary Voltage Ratings 208GrdY/120;416GrdY/240 or Customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Loop Feed or Radial Feed
- BIL 30/95kV
- Standards IEEE, CSA, DOE
- Application BESS, Crypto mining, Industry, Wind and Solar energy
- Power Rating 2500kVA
- Certificate UL, cUL, CSA, SGS
- 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
2500kVA Three Phase Pad Mounted Transformer
Technical Specifications
Accessories
| Rated Power | 2500 kVA |
| Rating Primary Voltage | 4.16-34.5kV or customized |
| Secondary Voltage | 480GrdY/277 208GrdY/120 400GrdY/230 Customized（208Y/120 V to 4,160 V） |
| Frequency | 50/60Hz |
| Vector Group | Dyn1/Yyn0/Dyn11/Dyn5 |
| Winding Material | Aluminum/Copper |
| Efficiency | As IEEE,Doe 2016,CAS Std or Customized |
| Impedance Voltage | Nominal 3.5% 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 | 1450 kg |
| Total Weight | 4900 kg |
| Outline Dimensions（L×W×H）in. | 1730×2100×2300（mm） |
| Lifting Lug | ELSP Fuse |
| Hinged Door | BAY-O-NET Fuse |
| Parking Bracket | Tap Changer |
| Tank Cover | Oil Level Gauge |
| L.V Bushing (4-Hole ) | Pressure Relief Valve |
| Two/Four Position Load break Switch | Vacuum Pressure Gauge |
| HV Grounding Copper Bar | Terminal Block |
| Temperature Indicator | Door Handle |
| H.V Bushing Well(15kV) | Ground Strap |
| Grounding Copper Bar | Nameplate |
| 1"'Drain Valve With 3/8" Sampler | IR Window |
| 1" Upper Fill Valve Filter Press Connection | Terminal Box |
| Non-PCB decal | High Voltage Warning Signs |
Customization Optional
2500kVA Three Phase Pad Mounted Transformer
In order to better meet the needs of different customers, the 2500KVA Three Phase Pad Mounted transformer transformer provides a variety of optional specifications, enabling it to provide customized power solutions according to actual application scenarios.
Input voltage (high voltage side) - You can select different input voltages such as 10kV, 15kV, 20kV, 35kV according to the voltage level of the power grid, and flexibly respond to the needs of different regions and power systems.
Output voltage (low voltage side) - You can select different low voltage output voltages such as 400V, 415V, 480V, 600V, etc. to meet the power needs of various loads.
Cooling method - Provide cooling methods such as ONAN (oil-immersed self-cooling) and ONAF (oil-immersed air cooling). Select the most suitable cooling solution according to the load requirements to ensure that the transformer works efficiently and stably.
Input voltage (high voltage side) - You can select different input voltages such as 10kV, 15kV, 20kV, 35kV according to the voltage level of the power grid, and flexibly respond to the needs of different regions and power systems.
Output voltage (low voltage side) - You can select different low voltage output voltages such as 400V, 415V, 480V, 600V, etc. to meet the power needs of various loads.
Cooling method - Provide cooling methods such as ONAN (oil-immersed self-cooling) and ONAF (oil-immersed air cooling). Select the most suitable cooling solution according to the load requirements to ensure that the transformer works efficiently and stably.
Protection level - According to the actual use environment, provide different protection levels such as IP44, IP54, IP55, etc. to ensure that the transformer can operate stably and long-term in a humid, dusty and corrosive environment.
Transformer oil - Provide different types of transformer oil, including mineral oil, FR3 environmentally friendly oil, etc., to ensure insulation performance while improving environmental protection standards.
These optional configurations ensure that the transformer can provide efficient and reliable power in a variety of power applications, while also meeting the needs of different environments and loads.
Transformer oil - Provide different types of transformer oil, including mineral oil, FR3 environmentally friendly oil, etc., to ensure insulation performance while improving environmental protection standards.
These optional configurations ensure that the transformer can provide efficient and reliable power in a variety of power applications, while also meeting the needs of different environments and loads.
Packing and Shipping
2500kVA Three Phase Pad Mounted Transformer
The 2500kVA three phase pad mounted transformer is meticulously packed to withstand global transportation challenges and arrive in optimal condition. The transformer tank, fully assembled with core, windings, and bushings, undergoes vacuum oil filling under controlled conditions to eliminate moisture and air pockets, ensuring dielectric integrity. All external accessories, including switches, fuses, gauges, and surge arresters, are securely mounted or separately crated to prevent damage.
Primary packaging involves a robust wooden crate or steel skid base reinforced with steel bands and corner protectors. The unit is wrapped in moisture-resistant VCI (volatile corrosion inhibitor) paper and plastic sheeting, with desiccant bags inserted to maintain low humidity during transit. For oil-filled units, oil is shipped separately in sealed drums or IBC totes if partial filling is preferred for weight reduction and safety regulations. Removable bushings and radiators are protected with wooden covers and foam padding.
Export crating complies with ISPM-15 standards for heat-treated wooden materials, featuring clear markings for handling, center of gravity, lifting points, and "Fragile - Electrical Equipment" warnings. Heavy-duty lifting lugs and jacking pads are highlighted for safe crane or forklift operations. The enclosure door is locked and sealed with tamper-evident tape, while weatherproof covers protect HV/LV compartments.
Shipping options are flexible to suit project timelines and logistics. Standard delivery uses flatbed trailers for domestic transport or specialized lowboy trailers for oversized loads, with pilot cars and permits arranged for road restrictions. For international shipments, we coordinate containerized (20ft/40ft open-top or flat-rack) or break-bulk ocean freight, securing the unit with lashing chains, turnbuckles, and blocking to prevent shifting during sea voyage. Air freight is available for urgent components if required.
Upon arrival, we provide detailed unpacking instructions, including oil topping-up guidelines if shipped dry or partially filled. Insurance coverage is arranged through reputable carriers, with full value declared for comprehensive protection against transit risks. Third-party inspections or witness testing can be coordinated at origin if specified. Our logistics team tracks shipments in real-time, offering proactive updates and customs documentation support (commercial invoice, packing list, certificate of origin, test reports) to expedite clearance and minimize delays at ports.
Primary packaging involves a robust wooden crate or steel skid base reinforced with steel bands and corner protectors. The unit is wrapped in moisture-resistant VCI (volatile corrosion inhibitor) paper and plastic sheeting, with desiccant bags inserted to maintain low humidity during transit. For oil-filled units, oil is shipped separately in sealed drums or IBC totes if partial filling is preferred for weight reduction and safety regulations. Removable bushings and radiators are protected with wooden covers and foam padding.
Export crating complies with ISPM-15 standards for heat-treated wooden materials, featuring clear markings for handling, center of gravity, lifting points, and "Fragile - Electrical Equipment" warnings. Heavy-duty lifting lugs and jacking pads are highlighted for safe crane or forklift operations. The enclosure door is locked and sealed with tamper-evident tape, while weatherproof covers protect HV/LV compartments.
Shipping options are flexible to suit project timelines and logistics. Standard delivery uses flatbed trailers for domestic transport or specialized lowboy trailers for oversized loads, with pilot cars and permits arranged for road restrictions. For international shipments, we coordinate containerized (20ft/40ft open-top or flat-rack) or break-bulk ocean freight, securing the unit with lashing chains, turnbuckles, and blocking to prevent shifting during sea voyage. Air freight is available for urgent components if required.
Upon arrival, we provide detailed unpacking instructions, including oil topping-up guidelines if shipped dry or partially filled. Insurance coverage is arranged through reputable carriers, with full value declared for comprehensive protection against transit risks. Third-party inspections or witness testing can be coordinated at origin if specified. Our logistics team tracks shipments in real-time, offering proactive updates and customs documentation support (commercial invoice, packing list, certificate of origin, test reports) to expedite clearance and minimize delays at ports.
32
32 years of industry experience
Manufacturer Test
2500kVA Three Phase Pad Mounted Transformer
Progress test
In the manufacturing process of 2500KVA Three Phase Pad Mounted transformer, in order to ensure that each transformer meets high quality standards, NPC electric will conduct strict quality inspections on all key materials (such as iron cores, winding wires, insulation materials, etc.) to ensure that they meet the design and technical requirements and ensure the basic quality of the transformer. Regular inspections and tests are carried out at various production stages of the transformer (such as iron core assembly, winding processing, oil immersion treatment, etc.). Through this series of progress tests, it is ensured that every link of the transformer strictly complies with the design and safety standards, minimizes potential problems in the production process, and provides reliable quality assurance for the transformers delivered to customers.
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
♦ 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
Induced voltage test at double frequency stresses inter-turn and layer insulation for partial discharge and corona-free operation. No-load loss and excitation current are measured at rated voltage to validate core performance and efficiency compliance with DOE 2016 levels. Load loss and impedance tests at rated current determine copper losses and percent impedance for system coordination. Oil dielectric breakdown, acidity, and moisture content are analyzed per ASTM standards to ensure fluid quality. Functional checks operate all switches, fuses, gauges, and alarms, including pressure relief device simulation. Optional special tests like sound level measurement, temperature rise (heat run if witnessed), or short-circuit withstand demonstration may be included. All results are documented in certified test reports with traceable calibration data, witnessed by customer representatives if required, confirming the transformer meets or exceeds specifications for safe, efficient field deployment.
Routine Test - Temperature Rise
Purpose of Testing
The purpose of the temperature rise test is to detect the temperature change of the equipment under working conditions by applying the rated load current or higher load current to ensure that the insulation performance of the equipment will not be degraded or damaged due to overheating during operation.
Testing Equipment
Temperature rise tester (e.g. OMRON, FLIR, Extech, etc.)
Heating source (e.g. electric heater, heater belt, or adjustable constant temperature heater, the specific power is selected according to the equipment requirements)
Temperature sensor (e.g. RTD sensor, thermocouple, to ensure accurate measurement)
Heating source (e.g. electric heater, heater belt, or adjustable constant temperature heater, the specific power is selected according to the equipment requirements)
Temperature sensor (e.g. RTD sensor, thermocouple, to ensure accurate measurement)
Pre-Test Preparation
Disconnect the device from the power supply and ensure that the device is properly grounded and discharged.
Ensure that the connection terminals and wiring are firm to avoid looseness affecting the test results.
Test under suitable environmental conditions: relative humidity below 75%, no rain (recommended temperature: 20-30°C).
Ensure that the connection terminals and wiring are firm to avoid looseness affecting the test results.
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 instrument correctly to the electrical terminals and temperature measurement points of the device under test (such as windings, cores, oil temperature measurement elements, etc.).
Initial condition record:
Measure and record ambient temperature, humidity, and atmospheric pressure at the start of the test.
Make sure the device is cold at the start.
Connect the test instrument correctly to the electrical terminals and temperature measurement points of the device under test (such as windings, cores, oil temperature measurement elements, etc.).
Initial condition record:
Measure and record ambient temperature, humidity, and atmospheric pressure at the start of the test.
Make sure the device is cold at the start.
Measure and Record
Record the following parameters regularly:
Temperature of each winding (by resistance method or temperature sensor)
Core temperature
Oil temperature (for oil-immersed equipment)
Current, voltage and power at the equipment end
Duration of load
Record changes in ambient temperature.
Temperature of each winding (by resistance method or temperature sensor)
Core temperature
Oil temperature (for oil-immersed equipment)
Current, voltage and power at the equipment end
Duration of load
Record changes in ambient temperature.
Temperature Correction
Correct the measured winding temperature rise (equipment temperature - ambient temperature) to the reference ambient temperature (usually 20°C or as required by the standard).
Repeat Testing (if necessary)
If the load is unstable or the measurement is abnormal during the test, reload and repeat the test process.
Evaluation Criteria (Reference)
The maximum temperature rise of the winding should not exceed the product standard or the manufacturer's specified value (for example: Class A insulation: ≤60°C temperature rise
Class B insulation: ≤80°C temperature rise
Class F insulation: ≤100°C temperature rise)
Class B insulation: ≤80°C temperature rise
Class F insulation: ≤100°C temperature rise)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Ideal for large commercial complexes, industrial parks, and manufacturing facilities requiring stable high-capacity power distribution. Also suits urban residential subdivisions, apartment complexes, and mixed-use developments with underground cabling, providing reliable step-down from medium voltage grids while maintaining aesthetic appeal and tamper-resistant safety in high-traffic areas.
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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