x
400kVA Dry type transformer4
400kVA Dry type transformer
400kVA Dry type transformer 2
400kVA Dry type transformer 3
400kVA Dry type transformer4
400kVA Dry type transformer
400kVA Dry type transformer 2
400kVA Dry type transformer 3

400kVA Dry Type Transformer

The NPC ELECTRIC 400kVA Dry Type Transformer is engineered for efficient and reliable power distribution in industrial, commercial, and utility applications. With a compact, fire-safe design, it operates without the need for oil or other cooling fluids, making it ideal for environments with strict safety and environmental standards. Designed to withstand heavy loads, it is the perfect solution for demanding electrical requirements, providing a sustainable and cost-effective option for modern electrical 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 Dry type transformer
BIL 30/95kV
Standards IEEE, ANSI, NEMA,IEC,GB
Application distribution networks, office buildings, transportation facilities,theaters, hospitals, hotels etc
Power Rating 400kVA
Certificate UL ,CESI
Cooling Method OA/OF
Opeartion Step Down & Step Up
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application

Technical Specifications

400kVA Dry Type Transformer
Technical Specifications
Accessories
  Technical Specifications
Rated Power 400 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
Enclosure material 304 Stainless Steel
Total Weight 1750 kg
Outline Dimensions(L×W×H)in. 1450×1250×1700(mm)
HV Bushing
LV Bushing
Tap changer connector
Lifting hook for complete transformer
Name plate

Customization Optional

400kVA Dry Type Transformer
Our transformers offer a range of core features designed to meet diverse application needs and ensure reliable performance.
The 400kVA dry-type transformer is designed to provide reliable and efficient power distribution in compact and environmentally sensitive environments. It features a rugged oil-free design that eliminates oil leaks and fire hazards, making it an ideal choice for safety-critical applications. The transformer uses a high-performance core and advanced insulation technology to ensure low energy losses and stable operation even under heavy loads.
This dry-type transformer is also very environmentally friendly as it does not require the use of hazardous oils, making it an ideal choice for environmentally friendly projects. Whether in commercial, industrial or urban environments, the 400kVA dry-type transformer provides a cost-effective and safe solution to modern power distribution needs.

Packing and Shipping

400kVA Dry Type Transformer
The packing and shipping process for the 200kVA Dry-Type Transformer is designed to ensure that the unit is safely transported and arrives in excellent condition at its destination. Each transformer is carefully packed using high-quality materials to provide maximum protection during transit. The process typically includes the following steps:
Protection and Wrapping: The transformer is securely wrapped in protective plastic or shrink film to safeguard it from moisture, dust, and scratches. Special attention is given to ensure the unit’s external parts, such as terminals and bushings, are fully protected.
Wooden Crate or Steel Frame: The transformer is placed in a custom-built wooden crate or mounted on a steel frame to provide structural support and prevent any physical damage during shipping. The crate is designed to withstand handling, loading, and unloading processes, while also offering protection against external impacts.
Shock and Vibration Protection: To minimize the risks of damage from shocks or vibrations during transportation, the transformer is cushioned with foam or other shock-absorbing materials inside the crate. This ensures that the unit remains stable and secure during its journey.
Labeling and Documentation: Each shipment is clearly labeled with essential information such as the destination address, handling instructions, and product details. Accompanying documents, including the packing list, shipping invoice, and product warranty, are included to ensure smooth customs clearance and efficient handling.
Shipping Methods: The transformers are typically shipped via sea freight, road transport, or rail, depending on the destination and customer requirements. The choice of shipping method is selected to ensure timely and cost-effective delivery, with tracking provided to monitor the shipment's progress.
Inspection Before Shipping: Prior to shipping, a final inspection is conducted to ensure that the transformer is in perfect working condition and that all protective measures have been properly implemented. This inspection ensures that the unit is fully operational upon arrival.
By using these comprehensive packing and shipping procedures, we ensure that the 200kVA Dry-Type Transformers are delivered to customers in pristine condition, ready for installation and use in a variety of industrial and commercial applications.
400kVA Dry type transformer package
400kVA Dry type transformer package mini
32
32 years of industry experience

Manufacturer Test

400kVA Dry Type Transformer
400kVA Dry type transformer Progress Test

Progress Test

The progress test for the NPC Electric 400kVA Dry-Type Transformer is an essential part of the quality assurance process, ensuring that the transformer meets the highest standards of safety, performance, and reliability. Throughout the manufacturing stages, the transformer undergoes several critical tests, including:

Dielectric Testing: To verify the insulation’s ability to withstand high voltages without breaking down, ensuring safety during operation.

Temperature Rise Testing: The transformer is subjected to both no-load and full-load conditions to monitor its temperature and ensure it operates within the allowable temperature limits.

Load Loss and No-Load Loss Measurement: These tests measure the energy efficiency of the transformer under different operating conditions, confirming that the transformer minimizes energy losses.

400kVA Dry type transformer  Design Tests

Design Tests

All transformer will be test after finished the production, test items as below:
♦ Insulation Power Factor
♦ 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)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Induced Voltage
♦ Lightning Impulse
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise

China NPC ELECTRIC

Transformer Factory Acceptance Test

NPC Electric conducts rigorous quality control testing on every transformer or representative samples, as well as on specific components and materials, to ensure compliance with design specifications throughout the production process.
The Factory Acceptance Test (FAT) for a 400kVA three-phase dry-type transformer is a critical step performed before shipment to verify that the unit meets all applicable standards and delivers optimal performance. The FAT includes the following key procedures:
Visual Inspection: Evaluates the transformer’s physical condition, including the enclosure, terminals, and labeling, to ensure conformance with design and safety requirements.
Electrical Testing: Involves measuring winding resistance, insulation resistance, and performing turns ratio tests to validate electrical integrity and functionality.
Dielectric Strength Test: Applies high voltage across the insulation system to ensure it can endure both normal and transient operating voltages without failure.
Load Testing: Simulates real-world operating conditions to assess the transformer’s voltage regulation, temperature rise, and overall efficiency under load.
Protection Device Testing: Verifies the proper operation of integrated protective components such as thermal sensors, temperature relays, and tap changers (if applicable).

Routine Test - Induced Voltage

Purpose of Testing
The purpose of winding resistance testing is to detect the continuity and connection quality of the internal conductors of the motor or transformer windings, and to promptly detect potential faults such as open circuits, poor contact or local heating.
Testing Equipment
Induced Voltage Tester (e.g. OMICRON, Megger, HioKI, etc.)
AC voltage source, commonly 2 kV, 5 kV, 10 kV, or customized according to test requirements.
Environmental thermometer and hygrometer, used to record the temperature and humidity of the environment for appropriate test evaluation.
Pre-Test Preparation
Disconnect all relevant power supplies and ensure that the equipment is properly grounded and discharged.
Check the connection wires and terminals to ensure they are secure and free of contamination.
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 equipment to the appropriate terminals or bushings of the device under test, ensuring that the connections are secure and properly grounded.
Apply Test Voltage:
Select the appropriate induction voltage according to the rated voltage and standard of the equipment.
Measure and Record
Start the test and record the following parameters:
Induced Voltage
Applied Current
Voltage peak, stability and waveform (waveform analysis)
Any abnormal current or voltage changes during the measurement process.
Temperature Correction
The measured induced voltage data is corrected to the reference temperature (usually 20°C) to ensure the accuracy of the test results.
Repeat Testing (if necessary)
If necessary, test different windings (HV, MV, LV) and bushings separately and compare the results at different test points.
Evaluation Criteria (Reference)
Inductive voltage ≤ 1% (Excellent): normally and meets safety standards.
1% < Inductive voltage ≤ 3% (Good): still within acceptable range.
Inductive voltage > 3% : faulty or not meet safety requirements and requires further analysis and repair.
Test standard
IEEE C57.12.01 & IEEE C57.12.91 (Dry-Type)
*These comprehensive tests ensure that each transformer meets performance standards and operates reliably under various conditions.
400kVA Dry type Transformer Routine Test

Technical Advantages

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

Product Packaging

Transformers Packaging (1)
Transformers Packaging (1)
Transformers Packaging (2)
Transformers Packaging (2)
Transformers Packaging (3)
Transformers Packaging (3)
Transformers Packaging (4)
Transformers Packaging (4)
Transformers Packaging (5)
Transformers Packaging (5)
Transformers Packaging (6)
Transformers Packaging (6)
Transformers Packaging (7)
Transformers Packaging (7)
Transformers Packaging (8)
Transformers Packaging (8)

Related Products

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