1250kVA Oil Immersed Transformer
NPC ELECTRIC's 1250kVA oil-immersed transformer adopts advanced design and manufacturing technology and complies with international power equipment standards (such as IEC, ANSI, IEEE, etc.). Its high-quality materials and strict quality control ensure the long-term reliability and safety of the equipment. The transformer has high efficiency and stable power transmission performance and is widely used in industrial, commercial, and power systems.
- 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 480/277V, 400/230V, 380/220V or customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Oil immersed distribution transformer
- BIL 30/95kV
- Standards IEEE, ANSI, NEMA, IEC, UL
- Application Industrial, Commercial and Power Systems
- Power Rating 1250kVA
- Certificate UL, CESI, CE
- 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
1250kVA Oil Immersed Transformer
Technical Specifications
Accessories
| Technical Specifications | ||
| Rated Power | 1250 kVA | |
| Rating Primary Voltage | 2.4 - 34.5kV | |
| Secondary Voltage | 480/277V 400/230V 380/220V Customized |
|
| Frequency | 50/60Hz | |
| Vector Group | Dyn11, Yyn0, Dyn5 | |
| 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 | 750 kg | |
| Total Weight | 4000 kg | |
| Outline Dimensions（L×W×H）in. | 2550 × 1600 × 2400（mm) | |
| HV Bushing |
| LV Bushing |
| Tap changer |
| Oil level gauge |
| Oil temperature indicator |
| Pressure relief device |
| Pressure vacuum gauge |
| Lifting hook for complete transformer |
| Name plate |
| Radiators |
| Oil upper filtering valve |
| Oil drain valve with 3/8" sampler |
Customization Optional
1250kVA Oil Immersed Transformer
NPC ELECTRIC's 1250kVA oil-immersed transformers offer a variety of optional specifications to meet the needs of different customers. The rated voltage of the transformer can be customized according to customer requirements, with common high-voltage and low-voltage combinations to adapt to different power transmission environments. In order to improve efficiency and safety, the transformer is equipped with an adjustable temperature control device to ensure its stable operation under various working conditions. The oil tank is made of high-strength steel, which has excellent corrosion resistance and pressure resistance, ensuring durability in long-term use. The optional temperature protection system and overload protection device can cut off the circuit in time when the equipment is abnormal to prevent damage.
Customers can also choose different types of cooling methods, such as natural air cooling and forced air cooling, to adapt to different ambient temperature requirements. The insulation system of the transformer is made of high-quality materials, which can effectively improve its short-circuit resistance and service life. In addition, an intelligent monitoring system can be configured according to needs to monitor the operating status of the equipment in real time, provide early warning information, and ensure the safe operation of the equipment.
Packing and Shipping
1250kVA Oil Immersed Transformer
NPC ELECTRIC's 1250kVA oil-immersed transformers are packed and transported with strict standards to ensure the safety and integrity of the equipment during transportation.
First, the transformer body is fixed with heavy wooden pallets to ensure that it will not move during transportation. The oil cylinder and electrical parts of the transformer are strictly sealed to avoid oil leakage and external contamination. All key components, such as bushings and oil pillows, are disassembled and packed separately to avoid damage during transportation. The outside of the transformer is protected by high-strength wooden boxes or steel frames to ensure that external impacts will not affect the equipment. Clear lifting instructions are marked on the packaging to ensure that the operator lifts correctly. The outside of the transformer is also covered with a moisture-proof and rust-proof protective film to effectively prevent moisture intrusion.
All transportation documents, such as packing lists, commercial invoices, bills of lading, and certificates of conformity, are prepared together with the goods to meet the requirements of the customs of the importing country. During transportation, special slings and lifting rings that meet the standards are used for lifting to ensure the stable lifting of the equipment. During transportation, the transformer will be transported by land using flatbed trucks or containers to ensure transportation efficiency and safety.
During long-distance transportation, the transformer will be strictly fixed and reinforced to avoid any damage caused by bumps. After arriving at the destination, the unloading will be carefully carried out according to the operating manual to ensure the smooth placement of the transformer. We provide detailed installation and commissioning guides to help customers successfully complete the installation and commissioning of the equipment.
Through this carefully designed packaging and transportation process, NPC ELECTRIC ensures that the 1250kVA oil-immersed transformer can reach customers safely and quickly to meet their usage needs.
First, the transformer body is fixed with heavy wooden pallets to ensure that it will not move during transportation. The oil cylinder and electrical parts of the transformer are strictly sealed to avoid oil leakage and external contamination. All key components, such as bushings and oil pillows, are disassembled and packed separately to avoid damage during transportation. The outside of the transformer is protected by high-strength wooden boxes or steel frames to ensure that external impacts will not affect the equipment. Clear lifting instructions are marked on the packaging to ensure that the operator lifts correctly. The outside of the transformer is also covered with a moisture-proof and rust-proof protective film to effectively prevent moisture intrusion.
All transportation documents, such as packing lists, commercial invoices, bills of lading, and certificates of conformity, are prepared together with the goods to meet the requirements of the customs of the importing country. During transportation, special slings and lifting rings that meet the standards are used for lifting to ensure the stable lifting of the equipment. During transportation, the transformer will be transported by land using flatbed trucks or containers to ensure transportation efficiency and safety.
During long-distance transportation, the transformer will be strictly fixed and reinforced to avoid any damage caused by bumps. After arriving at the destination, the unloading will be carefully carried out according to the operating manual to ensure the smooth placement of the transformer. We provide detailed installation and commissioning guides to help customers successfully complete the installation and commissioning of the equipment.
Through this carefully designed packaging and transportation process, NPC ELECTRIC ensures that the 1250kVA oil-immersed transformer can reach customers safely and quickly to meet their usage needs.
32
32 years of industry experience
Manufacturer Test
1250kVA Oil Immersed Transformer
Progress Test
NPC ELECTRIC's 1250kVA oil-immersed transformers undergo rigorous production testing during production to ensure that product quality meets international standards. First, after the transformer core and windings are precisely manufactured and assembled, insulation resistance tests are performed to ensure good insulation performance. Next, load and no-load tests of the transformer are performed to confirm that it operates within the design parameters and has excellent load response capabilities. After all tests are completed, the transformer will undergo a temperature rise test to ensure that it can maintain stable operation under high loads. After that, a short-circuit test is performed to verify the transformer's tolerance under abnormal conditions. Finally, after all tests are passed, NPC ELECTRIC will issue a detailed test report for the transformer to ensure that it meets customer requirements and is delivered on time.
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's 1250kVA oil-immersed transformers undergo a rigorous factory acceptance test (FAT) before leaving the factory.
The test first includes an inspection of the transformer's appearance and dimensions to ensure that all components are intact and meet the design standards. Next, the transformer's insulation properties are tested, including the dielectric strength and insulation resistance of the oil to ensure that it can withstand the rated voltage. Subsequently, a load test is carried out to simulate actual working conditions and check the transformer's temperature rise and operating stability under load. Next, short-circuit impedance and load loss tests are carried out to ensure that the transformer's efficiency and safety during operation meet the requirements. All test results are recorded and reports are generated by professional engineers to ensure that the quality and performance of the transformer meet international standards.
Through these rigorous factory acceptance tests, NPC ELECTRIC guarantees the reliability and long-term operational stability of the transformer, ensuring that customers' usage needs are fully met.
Routine Test - No Load Loss Test
Purpose of Testing
The purpose of No Load Loss Test is to measure the power loss of the equipment when it is not loaded to evaluate the iron loss and other core losses. This test can help understand the energy efficiency of the equipment and help determine the performance of the transformer or motor when it is running at no load.
Testing Equipment
No Load Loss tester (e.g. OMICRON, Megger, Schneider Electric, etc.)
Voltage source (usually 230V, 400V or customized according to customer requirements to adapt to different equipment)
Power analyzer (used to measure power loss and efficiency)
Ammeter and voltmeter
Temperature and humidity meter
Voltage source (usually 230V, 400V or customized according to customer requirements to adapt to different equipment)
Power analyzer (used to measure power loss and efficiency)
Ammeter and voltmeter
Temperature and humidity meter
Pre-Test Preparation
Disconnect all transformer tap-changers from the power supply and ensure that all equipment is properly grounded and discharged.
Perform the test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C). Avoid high humidity or bad weather that may affect the test accuracy.
Perform the test under suitable environmental conditions: relative humidity below 75% and no rain (recommended temperature: 20-30°C). Avoid high humidity or bad weather that may affect the test accuracy.
Test Progress
Connect the Test Instrument:
Connect the test equipment to the high voltage side of the transformer, making sure the wiring is correct and the equipment is grounded.
Apply Test Voltage:
Usually it is 110% of the rated voltage, for example, if the rated voltage of the transformer is 33 KV, apply 36.3 KV (110%).
Connect the test equipment to the high voltage side of the transformer, making sure the wiring is correct and the equipment is grounded.
Apply Test Voltage:
Usually it is 110% of the rated voltage, for example, if the rated voltage of the transformer is 33 KV, apply 36.3 KV (110%).
Measure and Record
Start the test and record the following parameters:
No Load Current
No Load Loss
Power Factor
Current
Voltage
Temperature and Humidity
No Load Current
No Load Loss
Power Factor
Current
Voltage
Temperature and Humidity
Temperature Correction
The power loss of the test results is corrected to a reference temperature (usually 20°C) to ensure an accurate evaluation.
Repeat Testing (if necessary)
Test at different rated voltages, especially when the transformer has multiple capacity levels, and perform no-load loss tests for each capacity level separately.
Evaluation Criteria (Reference)
No-load loss ≤ 0.2% rated power (excellent)
No-load loss < 0.2% ≤ 0.5% rated power (good)
No-load loss > 0.5% rated power (further inspection or corrective action required)
No-load loss < 0.2% ≤ 0.5% rated power (good)
No-load loss > 0.5% rated power (further inspection or corrective action required)
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Industrial, Commercial and Power Systems
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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