5000kVA Three Phase Pad Mounted Transformer
NPC ELECTRIC's 5000kVA Three Phase Pad Mounted Transformer (5 MVA) is a robust, liquid-immersed compartmental distribution transformer built for high-capacity outdoor pad-mounted installations on concrete foundations. Compliant with updated DOE energy conservation standards (post-2024 amendments, targeting high efficiency levels around 99.68% for 5000 kVA units), ANSI/IEEE C57.12.00, C57.12.34, C57.12.90, and related CSA/IEC norms, this transformer delivers top-tier energy efficiency, minimal no-load and load losses, and exceptional reliability in utility-scale, industrial, and commercial power systems. The tamper-resistant, weatherproof steel enclosure (dead-front or live-front) with NEMA 3R-equivalent protection ensures safety, reduced maintenance, and seamless blending into urban, suburban, or remote environments.
- 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, ANSI, NEMA, ASTM
- Application EV Charging
- Power Rating 5000kVA
- Certificate UL
- 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
5000kVA Three Phase Pad Mounted Transformer
Technical Specifications
Accessories
| Rated Power | 5000 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 | 3500 kg |
| Total Weight | 9700 kg |
| Outline Dimensions（L×W×H）in. | 2880×2200×2100（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
5000kVA Three Phase Pad Mounted Transformer
The optional specifications of the 5000kVA Three Phase Pad Mounted transformers provide a variety of customization options to meet different application scenarios and customer-specific needs, further improving the performance and adaptability of the transformer. Different voltage levels (such as 10kV, 13.8kV, 24kV, 33kV, etc.) can be customized according to customer needs to meet the requirements of various power systems.
Provides natural oil circulation cooling (ONAN) or forced air cooling (ONAF) to optimize heat dissipation performance according to actual load and environmental conditions. Optional transformer with load tap changer to facilitate voltage regulation and maintain stable voltage output.
Different types of insulating oils such as mineral oil, environmentally friendly vegetable oil or silicone oil can be selected according to application requirements to ensure environmental protection and high temperature performance. Optional reinforced insulation design is available to adapt to special environmental conditions such as high humidity, high pollution or high altitude areas.
Provides natural oil circulation cooling (ONAN) or forced air cooling (ONAF) to optimize heat dissipation performance according to actual load and environmental conditions. Optional transformer with load tap changer to facilitate voltage regulation and maintain stable voltage output.
Different types of insulating oils such as mineral oil, environmentally friendly vegetable oil or silicone oil can be selected according to application requirements to ensure environmental protection and high temperature performance. Optional reinforced insulation design is available to adapt to special environmental conditions such as high humidity, high pollution or high altitude areas.
An optional remote monitoring system can be used to monitor the transformer's temperature, oil level, load, partial discharge and other operating data in real time, so as to detect problems in advance and conduct intelligent operation and maintenance. A variety of protective devices such as lightning arresters, gas relays, pressure relief valves, oil level gauges, etc. can be equipped according to needs to further improve the safety and reliability of the transformer.
These optional specifications enable the 5000kVA three-phase box-type transformer to be customized according to specific application scenarios and customer needs, ensuring its stable and reliable operation in various environments.
These optional specifications enable the 5000kVA three-phase box-type transformer to be customized according to specific application scenarios and customer needs, ensuring its stable and reliable operation in various environments.
Packing and Shipping
5000kVA Three Phase Pad Mounted Transformer
The 5000kVA three phase pad mounted transformer is expertly packaged to endure rigorous handling and long-distance transport while preserving factory-fresh condition. Core-coil assembly undergoes vacuum drying and oil impregnation in a sealed, moisture-controlled process before tank closure, safeguarding dielectric strength. Where feasible, bushings, radiators, switches, fuses, and gauges ship factory-installed; otherwise, they are individually crated with vibration-dampening foam and supports.
The unit rests on a heavy-duty steel skid or reinforced export-grade wooden base, wrapped in volatile corrosion inhibitor (VCI) paper, multi-layer shrink film, and desiccant pouches to control humidity and prevent oxidation. Full oil-filled transport uses nitrogen blanketing for positive pressure; partial filling with separate sealed IBCs or drums lightens load (dry weight ~8000-10000 lbs, total ~22000-25000 lbs) and satisfies hazmat regulations. Removable bushings and fittings gain protective wooden enclosures and bracing.
Packaging follows ISPM-15 heat-treated lumber standards with steel strapping, edge reinforcements, and high-visibility labels indicating weight (approx. 10-12 tons filled), center of gravity, lift points, dimensions (~96-100" W x 96-108" D x 94-112" H), and warnings ("High Voltage Equipment - Specialized Handling Required"). Compartment doors lock with tamper-evident seals; weatherproof covers shield HV/LV bushings and accessories.
Domestic shipping employs lowboy trailers or extendable flatbeds for oversize loads, complete with permits, pilot/escort vehicles, and pre-planned routes to navigate restrictions. International options include 40ft open-top or flat-rack containers, or break-bulk/Ro-Ro ocean freight, with certified lashing (chains, turnbuckles, timber blocking) to secure against maritime forces. Real-time GPS tracking monitors progress; full cargo value insurance protects against loss or damage.
At destination, detailed instructions guide safe unloading via lifting lugs/jacking points, pad leveling, oil replenishment (if partial), grounding, and commissioning checks. Customs facilitation includes commercial invoices, packing lists, certificates of origin, test reports, and compliance documentation for efficient clearance. Pre-shipment third-party inspections or customer witnessing can be coordinated for added verification. Our logistics ensure regulatory compliance, reduced transit risks, and transformer arrival in optimal state ready for installation.
The unit rests on a heavy-duty steel skid or reinforced export-grade wooden base, wrapped in volatile corrosion inhibitor (VCI) paper, multi-layer shrink film, and desiccant pouches to control humidity and prevent oxidation. Full oil-filled transport uses nitrogen blanketing for positive pressure; partial filling with separate sealed IBCs or drums lightens load (dry weight ~8000-10000 lbs, total ~22000-25000 lbs) and satisfies hazmat regulations. Removable bushings and fittings gain protective wooden enclosures and bracing.
Packaging follows ISPM-15 heat-treated lumber standards with steel strapping, edge reinforcements, and high-visibility labels indicating weight (approx. 10-12 tons filled), center of gravity, lift points, dimensions (~96-100" W x 96-108" D x 94-112" H), and warnings ("High Voltage Equipment - Specialized Handling Required"). Compartment doors lock with tamper-evident seals; weatherproof covers shield HV/LV bushings and accessories.
Domestic shipping employs lowboy trailers or extendable flatbeds for oversize loads, complete with permits, pilot/escort vehicles, and pre-planned routes to navigate restrictions. International options include 40ft open-top or flat-rack containers, or break-bulk/Ro-Ro ocean freight, with certified lashing (chains, turnbuckles, timber blocking) to secure against maritime forces. Real-time GPS tracking monitors progress; full cargo value insurance protects against loss or damage.
At destination, detailed instructions guide safe unloading via lifting lugs/jacking points, pad leveling, oil replenishment (if partial), grounding, and commissioning checks. Customs facilitation includes commercial invoices, packing lists, certificates of origin, test reports, and compliance documentation for efficient clearance. Pre-shipment third-party inspections or customer witnessing can be coordinated for added verification. Our logistics ensure regulatory compliance, reduced transit risks, and transformer arrival in optimal state ready for installation.
32
32 years of industry experience
Manufacturer Test
5000kVA Three Phase Pad Mounted Transformer
Progress test
During 5000kVA pad mounted transformer production, core flux density validation optimizes magnetic performance to minimize hysteresis and eddy losses. Insulation drying in vacuum ovens logs temperature and vacuum profiles for complete dryness before oil contact. High-voltage lead positioning and clearance checks comply with BIL levels for surge resilience. Initial post-tanking oil fill allows low-voltage dielectric and excitation proving. Accessory functional progress cycles load-break switches, fuses, tap changers, gauges, and alarms repeatedly for reliability. Paint application measures dry film thickness, cure status, and adhesion for long-term environmental protection. Pre-acceptance audits verify nameplate accuracy, labeling, color consistency, and overall assembly readiness. Cumulative progress testing enables swift corrections, ensuring smooth advancement to full factory acceptance and dependable long-term service.
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
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
♦ Dielectric Withstand (Hipot)
Transformer Factory Acceptance Test
Factory acceptance testing (FAT) for the 5000kVA three phase pad mounted transformer complies with IEEE C57.12.90, C57.12.00, and client protocols to confirm performance before release. Routine visual/mechanical inspections review enclosure welds, paint quality, nameplate data, accessory mounting, and tamper-resistant elements. Winding resistance across all taps at reference temperature verifies conductor uniformity and loss calculations. Turns ratio (TTR) testing on every position ensures ratio accuracy within 0.5% and proper vector group. Polarity and phase relation checks align with specified connections. Insulation resistance at 5kV megger evaluates winding-to-winding/ground paths for high megohm values. Applied potential withstand applies one-minute test voltage to HV/LV per BIL class without breakdown or corona.
Routine Test - DC Insulation Resistance Test
Purpose of Testing
The purpose of DC insulation resistance testing is to measure the insulation resistance of a device by applying a DC voltage, thereby evaluating the health of the insulation material and the voltage withstand capability of the electrical device. This test helps detect potential insulation aging, moisture or damage, preventing electrical failures in the device.
Testing Equipment
Insulation resistance tester (e.g. Megger, Fluke, Hioki, Klein Tools, etc.)
Voltage source (usually 500V, 1000V, 2500V, or customized according to customer requirements)
Temperature and humidity meter (used to record the ambient temperature and humidity during the test to ensure that the test conditions meet the standard requirements.)
Voltage source (usually 500V, 1000V, 2500V, or customized according to customer requirements)
Temperature and humidity meter (used to record the ambient temperature and humidity during the test to ensure that the test conditions meet the standard requirements.)
Pre-Test Preparation
Make sure the device is properly grounded and fully discharged to prevent residual charge in the device from affecting the test results.
Perform the test under suitable environmental conditions. It is recommended to have a relative humidity below 75%, no rain, and a temperature range of 20-30°C to avoid moisture or temperature fluctuations affecting the test results.
Perform the test under suitable environmental conditions. It is recommended to have a relative humidity below 75%, no rain, and a temperature range of 20-30°C to avoid moisture or temperature fluctuations affecting the test results.
Test Progress
Connect the Test Instrument:
Connect an insulation resistance tester to the high voltage terminal of the device under test and to ground.
Apply Test Voltage:
Select an appropriate test voltage based on the rated voltage of the equipment .
Connect an insulation resistance tester to the high voltage terminal of the device under test and to ground.
Apply Test Voltage:
Select an appropriate test voltage based on the rated voltage of the equipment .
Measure and Record
Start the test and record the following parameters:
Insulation resistance value (MΩ)
Applied voltage
Ambient temperature and humidity during testing
Insulation resistance value (MΩ)
Applied voltage
Ambient temperature and humidity during testing
Temperature Correction
The measured insulation resistance values are corrected to a reference temperature (usually 20°C) for accurate evaluation.
Repeat Testing (if necessary)
Measure different windings (high voltage, medium voltage, low voltage) or each bushing separately, and conduct comparative analysis to ensure the insulation status of all parts.
Evaluation Criteria (Reference)
nsulation resistance ≥ 1000 MΩ (excellent)
500 MΩ ≤ Insulation resistance < 1000 MΩ (good)
100 MΩ ≤ Insulation resistance < 500 MΩ
Insulation resistance < 100 MΩ
500 MΩ ≤ Insulation resistance < 1000 MΩ (good)
100 MΩ ≤ Insulation resistance < 500 MΩ
Insulation resistance < 100 MΩ
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Perfect for large-scale industrial plants, petrochemical refineries, mining sites, and heavy manufacturing requiring substantial medium-voltage power distribution. Also fits expansive commercial campuses, hospitals, universities, stadiums, and urban mixed developments with underground cabling, providing secure, low-maintenance, tamper-resistant transformation in high-occupancy or regulated zones.
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
15kVA Completely self-protected(CSP) Single Phase Pole Mounted Transformer
NPC ELECTRIC the production of 15 kVA single-phase overhead transformers, meticulously engineered to meet international standards such as IEEE C57.12.00, IEEE C57.12.20, DOE-2016 Efficiency, CSA C2.1, and CSA C2.2. These certifications underscore to delivery products that are both safe and reliable. NPC electric transformers are designed to comply with the DOE 2016 efficiency standards, ensuring optimal energy efficiency and reduced operational costs. Understanding the diverse needs of our clients, NPC Electric offers a wide range of customizable voltage levels to suit various applications. Perfect manufacturing processes enable us to maintain short production cycles, ensuring timely delivery.
250kVA Three Phase Pad Mounted Transformer
The 250kVA Three Phase Pad Mounted Transformer is a compact, liquid-immersed, self-cooled (ONAN) distribution transformer optimized for efficient, underground power delivery in residential, light commercial, and small industrial applications. Fully compliant with IEEE C57.12.34, ANSI C57.12.00, DOE 2016 efficiency standards, and UL-listed, this compartmental-type unit features dead-front 200A high-voltage bushing wells (loadbreak inserts), radial or loop feed options, and a sealed tank using non-PCB mineral oil or FR3 natural ester fluid for improved fire safety and environmental performance.
35kV 46kV Power Transformer
NPC ELECTRIC's 35kV and 46kV power(electrical) transformer complies with international standards such as IEC and ANSI, and features high efficiency, low loss, and strong insulation. This product is widely used in power grid main transformers, power plants, industrial and mining enterprises, and large infrastructure projects. Key features include mineral oil or FR3 natural ester insulation (ONAN/ONAF/ODAF cooling options), copper or aluminum windings, primary voltages 35kV or 46kV (grounded wye or delta, with dual-voltage configurations), secondary voltages 6.6kV, 11kV, 13.8kV, 33kV, or custom (e.g., 13.8kV/480V or 35kV/11kV), BIL ratings 200–650kV depending on voltage class, impedance typically 8–12%, ±2×2.5% or ±5% off-load tap changer (OLTC optional), conservator tank or sealed tank design, Buchholz relay, pressure relief device, oil temperature gauges, winding temperature indicators, and ANSI 61 gray or custom tank finish.
5000kVA Dry Type Transformer
The NPC ELECTRIC 5000kVA Dry Type Transformer is a high-capacity, reliable power solution designed for large-scale industrial and commercial operations. With a robust 5000kVA rating, it features advanced dry-type insulation technology for enhanced safety, low maintenance, and long-lasting performance. Engineered for demanding environments, this transformer ensures stable, efficient, and quiet operation while minimizing environmental impact. It achieves efficiencies around 99.48% at 35% load per DOE 2029 levels for three-phase low-voltage dry-type at 5000 kVA (aligned/interpolated from published tables showing progressive gains and 20% loss reduction from prior baselines), accommodates high harmonics, overloads, and ensures long-term reliability with reduced environmental footprint and operational expenses.
380kV Oil-Immersed Power Transformer
NPC Electric 380kV Oil-Immersed Power Transformer is engineered for the most demanding extra-high voltage (EHV) transmission networks, providing a robust link between power generation and regional distribution. Utilizing a multi-step core stacking method with high-grade, laser-scribed silicon steel, this unit minimizes eddy current losses and vibration. The internal active part is submerged in high-dielectric-strength mineral oil, which serves both as a superior insulator and a high-efficiency coolant. Designed with a vacuum-proof, reinforced corrugated or radiator-type tank, it ensures hermetic integrity under extreme thermal cycling. With advanced electrostatic shielding and a focus on mechanical stability, this transformer offers unparalleled reliability for national grid backbones, ensuring continuous power flow with minimal maintenance requirements even in harsh environmental conditions.
50kVA Oil Immersed Transformer
50kVA Oil Immersed Transformer is usually pole mounted or installed in a distribution station for daily lighting and factory power, whose an LV output up to 0.4kV. The corrugated tank has thermal expansion and contraction components that enable the transformer oil to be completely isolated from the atmosphere. A distribution transformer can be manufactured according to the requirements of the client. This transformer is optimally designed by patented technology and software.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