250kVA Single Phase Pad Mounted Transformer
NPC ELECTRIC 250 kVA single phase pad mounted transformer operates safely, reliably, and efficiently and can be installed indoors and outdoors. The industrial transformer has a rated power of 250 kVA, a primary voltage of 27600/16000V single-phase and a secondary voltage of 120/240V single-phase.The transformer has a primary loop feed and dead front primary connections.
- 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 480-240/240-120or 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, NEMA
- Application Utility, Residential areas, Commercial hubs, Transportation centers, Airports etc.
- Power Rating 250kVA
- Certificate UL/cUL, CSA, CESI
- Cooling Method ONAN, ONAN/ONAF, KNAN, KNAN/KNAF
- Oil Minerial Oil or FR3
- Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
250kVA Single Phase Pad Mounted Transformer
Technical Specifications
Accessories
| Rated Power | 250 kVA |
| Rating Primary Voltage | 11950Delta or Customized |
| Secondary Voltage | 480-240V 240-120V 277V Customized |
| Frequency | 50/60Hz |
| Vector Group | Ii0,Ii6 |
| 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 |
| Insulating Oil Weight | 325 kg |
| Total Weight | 1106 kg |
| Outline Dimensions（L×W×H）in. | 1430×1300×1250(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 | Ground Strap |
| Grounding Copper Bar | Nameplate |
| 1"'Drain Valve With 3/8" Sampler | Non-PCB decal |
| 1" Upper Fill Valve Filter Press Connection | High Voltage Warning Signs |
Customization Optional
250kVA Single Phase Pad Mounted Transformer
The optional specifications for a 250kVA Single Phase Pad Mounted transformer typically include a range of features to meet various application requirements. These options may include different primary and secondary voltage combinations, such as custom voltage settings to suit specific load demands. The transformer may offer different feed configurations, such as radial or loop feed, as well as options for primary and secondary connections, including dead front or live front setups. Additional customization options could include various enclosure types with different IP (Ingress Protection) ratings for outdoor use, overload protection devices, metering provisions, and options for added cooling systems or remote monitoring. These optional specifications enable the transformer to be tailored for optimal performance, reliability, and safety in diverse installation environments.
Packing and Shipping
250kVA Single Phase Pad Mounted Transformer
NPC ELECTRIC three-phase transformers are designed to be securely packaged for sea freight transport, ensuring safe delivery across long distances.
For this purpose, The packaging and transportation of a 250kVA Single Phase Pad Mounted transformer follow specific standards to ensure safe delivery and protection against damage during transit.
The transformer is typically packaged in a robust wooden or metal crate with secure padding to prevent physical impact and vibrations. It is essential that the transformer is placed in a way that avoids strain on electrical connections, and sensitive components are adequately shielded from environmental factors like moisture, dust, and extreme temperatures. The package will often be labeled with handling instructions, such as "Fragile" or "Keep Dry," and include weight and dimension details for proper handling.
For transportation, the transformer is usually shipped via flatbed truck or container, depending on its size and destination. The unit is securely strapped and fastened to prevent shifting during transit. If shipping internationally, the transformer may be placed in a container, with proper customs documentation and adherence to international shipping standards.
Additionally, all transportation methods comply with safety regulations, ensuring the transformer reaches its destination in optimal condition.
32
32 years of industry experience
Manufacturer Test
250kVA Single Phase Pad Mounted Transformer
Progress Test
NPC Electric manufacturer pad mounted transformer have the strict quality control. The progress test for a 250kVA Single Phase Pad Mounted transformer typically involves a series of inspections and performance checks conducted at various stages of manufacturing to ensure the transformer meets quality and safety standards. This includes verifying the electrical parameters, such as voltage ratios, insulation resistance, and load performance, as well as checking for any physical defects or manufacturing discrepancies. The test also ensures that the transformer operates efficiently under both no-load and full-load conditions. Additional tests may include temperature rise tests, mechanical strength tests, and partial discharge testing to confirm the durability and reliability of the transformer in real-world conditions. These progress tests are crucial for ensuring the transformer’s compliance with industry standards and its readiness for safe, reliable operation.
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
NPC Electric will tests made for quality control by the manufacturer on every device or representative samples, or on parts or materials as required, to verify during production that the product meets the design specifications.
The Transformer Factory Acceptance Test (FAT) for a 250kVA Single Phase Pad Mounted transformer is a comprehensive series of tests conducted at the manufacturer’s facility before the transformer is shipped to the customer. The FAT ensures that the transformer meets all specified design, performance, and safety requirements. Key tests include verifying electrical parameters such as primary and secondary voltage, load testing, insulation resistance, and dielectric strength. The transformer’s mechanical and structural integrity is also tested, including the verification of physical dimensions, grounding, and the operation of protective devices. Additionally, temperature rise tests, no-load and full-load tests, and partial discharge tests may be performed to confirm the transformer's reliability and efficiency under real-world conditions. The FAT provides assurance that the transformer is fully functional, safe, and ready for installation upon delivery.
Routine Test - Excitation & No-Load Loss (Rated Voltage)
Purpose of Testing
The purpose of testing Excitation & No-Load Loss at rated voltage is to assess the transformer's core loss and magnetizing current under normal operating conditions, ensuring efficient performance and identifying any potential issues in the core or windings. This test helps verify that the transformer operates within specified parameters and meets its design requirements.
Testing Equipment
Test equipment: Excitation Test instrument (such as OMICRON, Megger, etc.)
Voltage source: usually rated voltage (such as 230V, 400V, 660V, customized according to equipment requirements)
Temperature and humidity meter: used to record ambient temperature and humidity conditions
Voltage source: usually rated voltage (such as 230V, 400V, 660V, customized according to equipment requirements)
Temperature and humidity meter: used to record ambient temperature and humidity conditions
Pre-Test Preparation
Disconnect and make sure the device is powered off and properly grounded and discharged.
Check the device terminals and wiring to ensure that the connection is secure and not loose or contaminated.
Ensure the test environment is suitable: relative humidity below 75%, no rain, and recommended temperature is 20-30°C.
Check the device terminals and wiring to ensure that the connection is secure and not loose or contaminated.
Ensure the test environment is suitable: relative humidity below 75%, no rain, and recommended temperature is 20-30°C.
Test Progress
Connect the Test Instrument:
Connect the test equipment to the appropriate terminals of the device under test and ensure that all connection points are properly grounded to avoid current leakage during the test.
Apply Test Voltage:
Select a suitable test voltage according to the rated voltage of the equipment (for example, the rated voltage is 11kV, 33kV or others), and ensure that the applied voltage is stable.
Connect the test equipment to the appropriate terminals of the device under test and ensure that all connection points are properly grounded to avoid current leakage during the test.
Apply Test Voltage:
Select a suitable test voltage according to the rated voltage of the equipment (for example, the rated voltage is 11kV, 33kV or others), and ensure that the applied voltage is stable.
Measure and Record
No-load current
No-load loss
Excitation loss
Power factor
Voltage
Current
Ambient temperature and humidity during testing
No-load loss
Excitation loss
Power factor
Voltage
Current
Ambient temperature and humidity during testing
Temperature Correction
The measured loss values and currents are corrected to a reference temperature (typically 20°C) for an accurate evaluation.
Repeat Testing (if necessary)
If necessary, measure the no-load loss and excitation loss of different windings (high voltage, medium voltage, low voltage) and at different voltage levels for comparative analysis.
Evaluation Criteria (Reference)
No-load loss ≤ rated loss (meets specifications)
No-load loss > rated loss (further inspection or corrective action required)
No-load loss > rated loss (further inspection or corrective action required)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Utility, Residential areas, Commercial hubs, Transportation centers, Airports, industrial facilities, Corporate enterprises, Medical institutions
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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