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800kVA Oil Immersed Transformer1
800kVA Oil Immersed Transformer2
800kVA Oil Immersed Transformer4
800kVA Oil Immersed Transformer5
800kVA Oil Immersed Transformer1
800kVA Oil Immersed Transformer2
800kVA Oil Immersed Transformer4
800kVA Oil Immersed Transformer5

800kVA Oil Immersed Transformer

The NPC ELECTRIC 800kVA Oil-Immersed Transformer is designed for high efficiency, durability, and reliable power distribution. Built to meet IEC 60076 and ANSI/IEEE standards, it ensures superior performance and safety. Certified for international quality compliance, it is ideal for industrial, commercial, and utility applications.
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, GB
Application Power Transmission and Distribution, Industrial Manufacturing, Commercial Facilities and New Energy Fields
Power Rating 800kVA
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

800kVA Oil Immersed Transformer
Technical Specifications
Accessories
  Technical Specifications
Rated Power 800 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 675 kg
Total Weight 3500 kg
Outline Dimensions(L×W×H)in. 1620 × 880 × 1520(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

800kVA Oil Immersed Transformer
NPC ELECTRIC's 800kVA oil-immersed transformers can provide a variety of optional specifications according to customer needs to meet different application scenarios and technical requirements. The primary and secondary voltages can be customized according to the power grid standards of different countries and regions, such as 6.6kV/400V, 10kV/415V, 11kV/433V, 20kV/400V, etc. ONAN (natural oil circulation/natural air cooling) or ONAF (natural oil circulation/forced air cooling) cooling methods are provided to adapt to different load conditions. Low-loss models can be customized according to IEC, GB, ANSI, DOE, and other standards to improve energy efficiency and are suitable for green energy-saving projects.
In addition, moisture-proof, anti-corrosion, and anti-salt spray coatings can also be selected to adapt to high humidity, coastal areas, or highly polluted industrial areas. These optional specifications ensure that NPC ELECTRIC's 800kVA oil-immersed transformers can meet the needs of various complex working conditions and different industries, providing higher reliability and operating efficiency.

Packing and Shipping

800kVA Oil Immersed Transformer
NPC ELECTRIC's 800kVA oil-immersed transformers are packed and transported to high standards to ensure that the equipment is safe and intact during transportation.
The transformer body is reinforced with heavy wooden pallets and equipped with shock-proof rubber pads at the bottom to reduce the impact of vibration. The exterior is sealed with weather-resistant plastic film and covered with a moisture-proof and rust-proof protective layer to prevent oil leakage and environmental factors. All oil valves, bushings, and radiators are strictly sealed to prevent leakage or damage during transportation. The exterior of the transformer is packed in reinforced wooden boxes or steel frame structures, and the outer boxes are marked with signs such as "Do not dump", "Handle with care" and "Lifting Guide". Matching accessories and vulnerable parts such as high and low voltage bushings, temperature controllers, silicone desiccant, etc. They are packed separately and packed in special wooden boxes or thickened cartons. Each transformer is accompanied by a complete packing list, certificate of conformity, instruction manual and test report to ensure that customers can accept it correctly.
Domestic transportation uses professional flatbed trucks to ensure that the transformer is fixed firmly and reinforced with straps to prevent sliding. International transportation is carried out by container or bulk carrier, and an anti-vibration support structure is provided when necessary to ensure the stability of the equipment during long-distance transportation. All packaging complies with international shipping, rail, and road transportation standards, and additional protection measures can be provided according to customer needs.
800kVA Oil Immersed Transformer package
800kVA Oil Immersed Transformer package mini
32
32 years of industry experience

Manufacturer Test

800kVA Oil Immersed Transformer
800kVA Oil Immersed Transformer Progress Test

Progress Test

NPC ELECTRIC's 800kVA oil-immersed transformers undergo rigorous manufacturing process testing during production to ensure product quality and stable performance. First, the transformer core material is sheared and stacked with high precision to reduce no-load losses. Subsequently, the coils made of high-quality copper wire are strictly insulated and vacuum dried to remove moisture. After the coils and cores are assembled, preliminary electrical tests are carried out, including insulation resistance and winding DC resistance measurements. The transformer oil is filtered and degassed before being filled into the oil tank to ensure good insulation performance and heat dissipation. After assembly, the transformer undergoes type tests such as power frequency withstand voltage, induction withstand voltage, and partial discharge to ensure that the electrical performance meets the standards. Finally, the finished product undergoes a load test and a temperature rise test to verify stability under actual operating conditions. After all tests are completed and passed, the transformer will be packaged and prepared for shipment to the customer's designated location.

800kVA Oil Immersed Transformer  Design Tests

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)

China NPC ELECTRIC

Transformer Factory Acceptance Test

NPC ELECTRIC's 800kVA oil-immersed transformers undergo rigorous factory acceptance tests before leaving the factory to ensure that their performance meets international standards.

First, the transformer is visually inspected to confirm that the housing, terminal blocks, and nameplate information are intact. Then winding resistance test is performed to verify the integrity and conductivity of the coil. The insulation withstand voltage test ensures that the transformer can operate safely at rated voltage and has sufficient insulation strength. Short-circuit and no-load loss tests are used to measure the energy efficiency of the transformer to ensure that the power loss meets the design standards. The ratio test is used to confirm whether the voltage ratio of each winding meets the technical parameters. 

After all tests are completed, a detailed test report is issued to ensure that the product meets customer and industry requirements.

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
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.
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.
Measure and Record
No-load current
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)
*These comprehensive tests ensure that each transformer meets performance standards and operates reliably under various conditions.
800kVA Oil Immersed Transformer Routine Test

Technical Advantages

● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions

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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.

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