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Oil-Immersed Transformer-High Voltage 66KV

High-Voltage Oil-Immersed Transformer — OEM/ODM & Wholesale Supplier

The 66kV oil-immersed distribution transformer delivers stable, low-loss power for medium-voltage grids, serving industrial parks, mines and transport hubs. Manufactured by Subian Electric, it offers strong short-circuit tolerance and quiet operation. As a professional manufacturer and factory supplier, Subian Electric welcomes enquiries from distributors, wholesalers and project buyers.

66kV — Oil-Immersed Distribution Transformer66 kV · Three-Phase · ONAN
66 kV
Low Loss
Strong Short-Circuit Tolerance

Key Specifications

  • Voltage Level — 66 kV, three-phase
  • Application — Transmission and distribution links
  • Loss Level — Lower than national standards
  • Cooling — Oil-immersed (ONAN)
  • Noise — Quiet operation
  • Tolerance — Strong short-circuit tolerance
  • Standards — IEC 60076 / GB 1094

Product Overview

66kV High-Voltage Oil-Immersed Transformer from Subian Electric’s Xuzhou Factory

The 66kV power transformer that uses oil for its function has a very good potential in power e.g. the transformer can be used in medium voltage networks serving industries, mining sites and transport connections continuously. The transformer has a good ability to withstand short-circuit operation as well as low losses of electricity as compared with the requirements established by the country.

Oil-Immersed Transformer-High Voltage 66KV — Applications & circuit protection applications

Applications & circuit protection

This transformer is suitable for transmission and distribution installation for business electrical applications, city and rural agricultural distribution and infrastructure projects.

  • Industrial parks: Reliable energy supply for big facilities.
  • Mines: Mining operations of non-metallic and metallic substances.
  • Transport: Roads, airports and railways infrastructure.
  • Regional grids: Distribution and transmission facilities.
Oil-Immersed Transformer-High Voltage 66KV construction and operating reliability

Construction & operating reliability

Superior-quality materials for core and windings, effective cooling, and strong structural design ensure great efficiency and long performance period.

  • Three-phase design of 66 kV.
  • Lower losses than defined by national standards.
  • Strong short circuit resistance.
  • Silent operation.
  • Reliable support of infrastructure projects.

Technical Parameter

Parameter Value
Rated capacity range 6300-63000 kVA
Voltage combination (HV) 110 ±8×2.5% kV
Tap range 36 / 37 / 38.5 kV (MV)
Voltage (LV) 6.3 / 6.6 / 10.5 / 21 kV
Connection group YNyn0d11
No-load loss (typical range) 8900-25000 W
Load loss (typical range) 44000-300000 W
No-load current (typical range) 0.4-0.76%
Short-circuit impedance 10.5% (H-M)
Voltage level 66 kV, three-phase
Application Transmission and distribution links
Cooling method Oil-immersed (ONAN)
Loss level Lower than national standards
Short-circuit tolerance Strong
Noise Quiet operation
Standard IEC 60076 / GB 1094

Transformer Price & Factory Quotation

As we are a factory-direct manufacturer, we price transformers depending on the rated capacity, combination of voltages, core and windings materials, accessories, and order quantity. For container orders as well as for distributor programs volume pricing is applied. Since the costs for materials move freely in the market, we provide quotations on actual prices in written form only. Ask us for a price list for High-Voltage Oil-Immersed Transformer specifying targeted capacity and quantity required.

  • OEM / ODM branding does not adjust the price of a standard transformer series
  • Prices for spare core, spare unit, and special packaging are given separately
  • FOB / CIF / DDP terms are available for the export.

How to Connect This Transformer

Prior to applying the supply voltage to the High-Voltage Oil-Immersed Transformer, ensure that the tap position corresponds to the supply voltage to be used, as well as that the connection grouping suits your system. The connections are made as follows: high voltage bushings go to the supply side, and low voltage terminals to the load side. Earthing terminals should be properly connected to station earth in accordance with local standard.

  • Verify tap position based on supply voltage
  • Connect HV bushings to supply side, LV terminals to load side
  • Connect earthing terminals accordingly to local standards

This Transformer vs. Alternative Ratings

Compare typical configurations to select the correct rating:

Item This Product Smaller / Larger Option
Capacity As specified on this page Lower or higher kVA available
Voltage As specified Other primary voltages available
Impedance Per standard / custom Adjusted to network requirements
Cooling ONAN or AN/AF per type Forced cooling option on request
Application Distribution / power Industrial, renewable or utility

Export Markets & Country Compatibility

We provide High-Voltage Oil-Immersed Transformer to parts dealers, power utilities and project customers in Asia, Africa, Middle East countries, Latin America and Europe. At the time of shipment we finalize the applicable voltage, frequency, connection group and certification criteria for all destinations.

Transformer Dimensions, Weight & Packing

Capacity, voltage, and type are the factors that affect dimensions as well as weight. The typical approximate dimension values for distribution ratings are as follows: 100 kVA oil immersed devices will have dimensions of approximately 1000-1200 mm for length, 500-700 mm for depth, and 1100-1400 mm for height while shipping weight is around 600-900 kg. The dimensions of larger units change also. Actual dimensions of ordered products and transportation weight are confirmed when the order is placed as well as packing according to the way of transportation.

  • Dimension drawings are approved before production
  • Packing is carried out according to standard with marked lifting places
  • Transport method is confirmed while planning delivery

Oil-Immersed Transformer-High Voltage 66KV standards and certifications

Standards & certifications

In accordance with IEC 60076 and GB 1094 standards, the transformer can be provided with results regarding type tests carried out for the project approval purpose.

  • Design standard: IEC 60076 / GB 1094.
  • Provision of type-test and routine-test results.
  • Low-loss design confirmed.
  • Documentation for approvals and certifications is available.
Oil-Immersed Transformer-High Voltage 66KV OEM and B2B supply support

OEM & B2B supply support

Subian Electric produces and supplies electrical equipment and is a supplier of equipment to electric power companies, infrastructure constructors and traders.

For custom capacity, voltage equation or tap changes, please get in touch with us and understand the project we are dealing with and quantity needed.

  • Sample products and technical designs are provided.
  • Flexible purchasing quantity is available.
  • OEM and ODM services are offered.
  • Custom design and packaging of the products are available.
  • Support with technical documentation and certificates is provided.


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Frequently Asked Questions

What is the 66kV transformer used for?

66kV transformers are essential in the management of medium voltage networks. They work in the transmission of electricity to industrial facilities, as well as mines and transport facilities.

What makes it efficient?

Because the loss factors are below national standards, this allows to save on energy consumption costs.

Is it suitable for infrastructure projects?

66kV transformers are ideal for highways, ports, mines, as well as different industrial parks.

Do you provide test reports?

We provide type test reports and routine test reports in order to assist with project approval and product certification.

Subian Electric Power manufacturing facility in Xuzhou
Manufacturing Base

Large Power Transformer Production in Xuzhou

Subian's 30,000-square-metre facility in Xuzhou supports large power transformer production up to 110 kV class, with heavy-duty lifting, large core stacking bays, tank fabrication, oil treatment plant and a high-voltage test area. Units are manufactured and tested entirely at this site. In-house production and testing of the High-Voltage Oil-Immersed Transformer follow the same controlled process at this facility. Routine test records, production photos and certificates give you proof of quality before and after shipment. Every order is engineered to your voltage, capacity and connection requirements instead of forcing a standard unit.
  • Power transformers configured for projects up to 110 kV class
  • Project-based technical support for utilities, EPC contractors and buyers
Factory Facilities

Heavy Equipment and High-Voltage Test Areas

The images show the large transformer workshop, core and tank assembly areas, and customer inspection activities for power transformers at Subian's Xuzhou facility. The High-Voltage Oil-Immersed Transformer supplied on this page is manufactured, tested and quality-checked at this site. Routine tests recorded and reviewed before dispatch. Ratio, losses and insulation verified on the test bench.
Subian large power transformer production workshop
Winding processControlled winding with layer insulation per drawing.
Power transformer assembly area inside the Subian factory
Customer visitsBuyers can inspect units and review records at the plant.
International customer inspecting a power transformer at the factory
AssemblyCore-coil assembly and tanking on dedicated stations.
Manufacturing Process

Controlled Assembly for High-Voltage Reliability

Large power transformer manufacturing follows a documented process: core cutting and stacking, coil winding with insulation, drying, core-coil assembly, tanking, vacuum oil filling, and a full routine test sequence. Manufacturing of the High-Voltage Oil-Immersed Transformer follows the confirmed specification, with checks recorded at each relevant stage. Quality insulation, verified windings and proper oil treatment are designed to reduce unplanned outages at your site. Low-loss design keeps no-load and load losses within specification, so energy consumed over the transformer's long service life stays minimal.
  • Insulation applied to the approved design and production drawings
  • Vacuum drying and oil filling with controlled oil quality
  • Routine tests recorded and reviewed before dispatch
Power transformer coil winding production line
Production & Inspection
Power transformer assembly process
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Technician carrying out transformer winding work
Quality centerRoutine tests recorded and reviewed before dispatch.

Insulation System and Oil Treatment

Pressboard barriers, lead insulation and clearances follow the approved design. Oil is dehydrated and degassed before vacuum filling, and final oil tests confirm dielectric strength. By capacity, voltage, loss level, materials and quantity. We send a written quotation against your exact specification, with volume pricing for larger orders. Specification and quantity. We quote against your requirements, and factory-direct pricing applies to all orders. Every unit is routine-teste
Transformer core manufacturing detail
Production follows the confirmed specification, with test records kept for every unit.Share your specification or just your application — our team will advise.
Visitors at the Subian power equipment booth
Subian booth at an international electrical exhibition
Subian team meeting a customer at an electrical exhibition
Customer visiting the Subian transformer booth
Subian international exhibition team
Subian sales representative discussing a project with a visitor
Visitors at the Subian power equipment booth
Subian booth at an international electrical exhibition
Customer Meetings

Power Transformer Project Discussions

Our engineers meet utility buyers, EPC contractors and project owners at exhibitions to review power transformer specifications including voltage class, rating, impedance, tap changers and transport constraints. Extending and upgrading distribution in utility programs where units stay in service for decades. Supplying factories, mines and processing plants that need dependable power for continuous production. Step-down and step-up duties in medium-voltage distribution
Contact Our Export Team
Product Documentation

Power Transformer Certificates and Test Records

Type-test reports, routine test records, factory certificates and shipping documents for power transformers are prepared according to the contract and destination market. For the High-Voltage Oil-Immersed Transformer, certificates, type-test reports and routine test records can be confirmed before ordering. Yes. OEM and ODM supply includes custom nameplates, packaging and documentation for distributors and brands. Standard routine tests include winding resistance, ratio and vector group, no-load and load loss, impedance, insulation and oil tests.
Example transformer conformity certificate
Factory certificates
Example English transformer type test report
Type-test reports
Packed Subian power equipment prepared for delivery
Packing and shipmentLarge transformers are prepared for shipment with confirmed lifting, oil preservation and transport arrangements.
Product Inquiry

Request Product Information and Pricing

Please provide the product type, rated voltage, capacity, quantity, applicable standard, delivery country and required delivery date. We will reply with a quotation or a list of points requiring confirmation.
  • Product selection and technical clarification
  • OEM, ODM and private-label requirements
  • Quantity, packing and delivery planning

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