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35kV Oil Immersed Power Transformer for Armenian

TAILI 35kV Oil Immersed Voltage Transformer is designed for 35kV and 38.5kV power systems that require stable voltage conversion, low energy loss, and long-term dependable operation. It is widely used in power substations, utility networks, industrial plants, and large-scale power distribution projects. With flexible configuration options such as ONAN or ONAF cooling, hermetically sealed or conservator tank design, copper or aluminum windings, and off-circuit or on-load tap changer, this transformer can be customized to meet different project requirements. It is widely used in substations, utility networks, industrial plants, commercial facilities, mining projects, and infrastructure developments.

Built with advanced core technology and a durable insulation system, TAILI Three Phase Oil Immersed Power Transformer delivers excellent energy efficiency, strong short-circuit resistance, and dependable operation under various environmental conditions. Customized solutions are available for different voltage classes, capacities, cooling methods, and installation requirements.

Looking for a reliable 38.5kV oil immersed power transformer supplier? We provide custom engineering support, technical drawings, and project-based solutions for utility and industrial applications. Contact us for a tailored quotation.

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38.5kV 10MVA Oil-Immersed Power Transformer

TAILI’s 35kV-38.5kV 10MVA oil-immersed voltage transformer is engineered for industrial substations, utility grids and high-demand power systems. It supports 6.3kV, 11kV, 15kV and project-specific secondary voltages, with ONAN or ONAF cooling available according to loading and temperature-rise requirements.

The electrical design, tap range, vector group, impedance, insulation level and accessories can be configured to match the project single-line diagram and technical specification.

35kV-Class Power Transformer Specifications

The table distinguishes the featured product rating from configurable options. Final values are agreed in the approved technical datasheet, including the cooling stage associated with the rated capacity.

Parameter	Featured Rating or Published Option	Project Selection Note
Transformer type	Three-phase oil-immersed power transformer	For medium-voltage transformation in substation and industrial systems.
HV rated voltage	38.5kV	Featured rating on this page; other primary voltages require a separate configuration.
LV rated voltage	6.3kV, 11kV or 15kV; other values by project review	Select the required secondary rating. LV identifies the lower-voltage winding, which can still operate at medium voltage.
Rated capacity	10MVA	Featured product rating; confirm the ONAN/ONAF rating schedule if forced-air cooling is specified.
Vector group	Dyn11, Dyn5, Yyn0 or project-specific design	Confirm winding connections, phase displacement, neutral requirements and parallel-operation compatibility.
Impedance	4% or 6% — published reference options	Confirm the guaranteed value for the selected 10MVA design, reference temperature and system fault level.
Tap changer	DETC or OLTC, according to the selected design	Specify the fitted type. DETC adjustment requires de-energization; OLTC supports tap changes while supplying load.
HV tapping range	±2 × 2.5% — published option	Confirm tap range and positions for the fitted tap changer; do not assume this is the OLTC schedule.
Cooling method	ONAN or ONAF	ONAN uses natural oil and air circulation; ONAF adds forced-air cooling through fans.
Tank design	Conservator type or hermetically sealed design	The selected tank system determines the oil-expansion arrangement and applicable protection accessories.
Winding material	Copper or aluminum, as specified	Confirm material together with guaranteed losses, temperature rise and dimensions.
Standards	IEC, IEEE, ANSI, DOE
Certificates	CE, SGS, CNAS

For other capacities, TAILI’s 35kV oil-immersed power transformer series lists ratings from 2.5MVA to 31.5MVA, including 35kV, 36kV and 38.5kV primary-voltage options. These are separate project configurations.

Armenia Steel Plant Supply Reference: 38.5kV to 6.3kV Transformer Supply

For an Armenian steel plant power-system upgrade completed in March 2025, TAILI manufactured two transformers for 38.5kV-to-6.3kV power conversion.

The project required coordination of electrical parameters, mechanical design, factory testing, export packaging and delivery. This reference demonstrates TAILI’s ability to support customized medium-voltage transformer projects for steel plants and other heavy industrial facilities.

Project Item	Reference Details
Location and sector	Armenia — steel plant power-system upgrade
Reference date	March 2025
Transformer quantity	Two power transformers manufactured
Voltage conversion	38.5kV to 6.3kV

Voltage-Conversion Requirement

The project required transformation from 38.5kV to 6.3kV for a steel plant power-system upgrade. This voltage pair defines the interface between the incoming supply and the plant’s lower-voltage system.

Manufacturing and Supply Coordination

TAILI manufactured two power transformers for this requirement. The published supply reference identifies coordination of electrical parameters, mechanical design, factory testing, export packaging and delivery.

Confirmed Project Milestone

TAILI completed transformer manufacturing for the steel plant upgrade. This provides an example of customized medium-voltage transformer supply for a heavy industrial project.

See the Armenia steel plant transformer project for the project reference.

Features of 35kV Oil Immersed Power Transformer

High Electrical Efficiency

The magnetic core and winding design control no-load loss, load loss and operating temperature. Guaranteed performance values are confirmed in the approved technical datasheet and checked during factory testing.

Strong Mechanical Construction

The winding support and clamping structure are designed to withstand transport vibration and electromechanical forces during system faults. The final short-circuit withstand design is based on rated current, impedance and network fault level.

Reliable ONAN or ONAF Cooling

ONAN cooling is suitable for standard natural oil and air circulation. ONAF cooling can be specified when additional cooling capacity or staged loading is required.

Project-Specific Voltage Regulation

The tap range and tap-changer type are selected according to voltage fluctuation and operational requirements. Off-circuit or other regulating solutions must be confirmed during engineering review.

Flexible Customization

Available in multiple voltage ratings, capacities, vector groups, tap changers, and tank structures to meet project demands.

Power Transformer vs. Distribution Transformer

Both transform electrical voltage. The names usually describe their position and duty in the power system, rather than a universal capacity or voltage boundary. A transformer used in a regional distribution substation may also be described as a power transformer.

Selection Factor	This Power Transformer Configuration	Typical Final Distribution Transformer
System role	Transformation between an incoming medium-voltage supply and a plant or regional feeder bus.	Transformation near the point of use to supply downstream equipment or buildings.
Voltage interface	38.5kV primary with a selected 6.3kV, 11kV or 15kV secondary.	Often a medium-voltage primary and low-voltage secondary, such as 0.4kV, depending on the network.
Capacity selection	The featured product is rated 10MVA for aggregate substation or industrial loads.	Selected for the served load; capacity ranges vary and can overlap with power transformers.
Voltage regulation	DETC or OLTC is selected for the required operating strategy.	DETC is common, but OLTC-equipped distribution designs also exist.
Procurement priorities	Voltage ratio, fault duty, vector group, impedance, thermal rating and protection interfaces.	Load profile, voltage ratio, losses, installation space and local network requirements.

Core Technical Advantages

Low-Loss Silicon Steel Core

A high-permeability silicon steel core supports low no-load loss by controlling magnetic losses in the core. For procurement, compare guaranteed no-load and load losses at the stated test conditions rather than relying only on an efficiency claim.

Strong Short-Circuit Withstand Capability

Winding supports and clamping structures are designed to resist electromechanical forces during external faults. The required withstand duty depends on rated current, transformer impedance, network fault level and fault duration. Define the required calculation, evaluation or test evidence during specification review.

Efficient Heat Dissipation

Insulating oil transfers heat from the active part to the tank and radiators. ONAN cooling uses natural circulation; an ONAF configuration adds fans for additional cooling. Ambient temperature, altitude and the load profile should be included when agreeing temperature-rise limits and cooling-stage ratings.

Flexible Voltage Regulation

A DETC configuration suits projects where tap changes can be made during a planned outage. OLTC is an alternative when adjustment is required while the transformer supplies load. Specify the tap range, step size, number of positions and any control requirements for the selected design.

Outdoor Installation Capability

The tank, external cooling equipment and bushings can be configured for outdoor service. Define temperature range, altitude, pollution, corrosion exposure and bushing creepage requirements during enquiry. Control-enclosure protection should be specified separately from the main tank design.

Production of 35kv Oil Immersed Power Transformer

01 Production Equipments for Oil transformers

35kv Oil Immersed Power Transformer

02 Oil immersed power transformer spare parts

35kv Oil Immersed Power Transformer

03 Power transformer

35kv Oil Immersed Power Transformer

04 Structural Advantages

The transformer adopts a high-permeability silicon steel core to reduce losses and improve efficiency. Precision windings with strong insulation performance ensure safe and stable operation. The oil tank structure is designed for effective cooling, moisture protection, and long-term reliability.

Radiators, conservators, bushings, protection devices, and monitoring accessories can be configured according to customer requirements.

Application scenarios

Power Utilities & Grid Distribution Systems

This includes urban and township substations, regional distribution stations, long-distance distribution nodes, and grid expansion or upgrade projects. 35 kV transformers are mainly used for stepping down 35 kV to medium-voltage levels (10–22 kV) for stable regional power supply.

Industrial, Infrastructure & Energy Projects

Widely applied in industrial parks, manufacturing plants, mining sites, oil and gas fields, data centers, airports, ports, rail transit systems, and renewable energy plants (solar/wind). They provide reliable medium-voltage power for large-scale industrial and infrastructure loads.

Rural Electrification & Public Utilities

Used in rural power networks, agricultural irrigation systems, new rural development, and public facilities such as hospitals, schools, and government buildings. The 35 kV voltage level offers long transmission distance and cost-efficiency, making it ideal for rural and remote-area electrification.

Package and Shipping

35kv Oil Immersed Power Transformer

Transformer Accessories and Configuration

Accessories are selected around the tank design, cooling method and protection scheme. The approved bill of materials should identify each supplied item, its rating, quantity and required alarm or trip contacts.

Accessory	Function	Configuration Note
Conservator	Accommodates changes in oil volume as temperature changes.	For the selected conservator-type design; a hermetically sealed tank uses a different expansion arrangement.
Radiators	Transfer heat from the circulating oil to the surrounding air.	Size and arrangement follow the thermal design; fans are specified for ONAF where required.
Buchholz relay	Detects gas accumulation and oil surges associated with internal faults.	Applicable to a conservator system, normally in the pipe between the main tank and conservator.
Pressure relief device	Relieves excessive internal tank pressure.	Specify the device rating and any required signalling contacts.
Oil level indicator	Provides a visible indication of oil level.	Confirm mounting location and whether low-level alarm contacts are required.
Oil temperature indicator	Monitors oil temperature for inspection and temperature-related signalling.	Confirm alarm/trip contacts; winding-temperature monitoring is a separate requirement.
HV bushings	Provide insulated HV connections through the tank boundary.	Specify voltage, current, insulation level, creepage distance and connection orientation.
LV bushings	Provide insulated connections for the lower-voltage winding.	Confirm current rating, terminal arrangement, busbar/cable interface and neutral connection where required.

Service System

Pre-sales support

- Provide customized power distribution scheme design to optimize cabinet size, equipment layout and product configuration;

- For special needs (such as non-standard voltage, explosion-proof certification), provide detailed technical solutions within 12 hours.

Routine tests:

-Measurement of winding resistance

-Measurement of voltage ratio

-Check of vector group

-Mesurement of impendance voltage and load loss

-Measurement of no load oss and current

-Separate-source voltage withstand test

-Induced overvoltage withstand test

-Dimension checking

Type Tests

-Lighting impulse test

-Temperature rise test

After-sales guarantee

- Quick response: reply to fault report within 24 hours, remote debugging or on-site service within 48 hours (domestic);

- Regular return visits: inspect the operation status of the equipment free of charge every year and provide maintenance suggestions;

- Transparent service: the cause of the failure is explained in writing, the maintenance cost is priced according to the market standard, and the cost is refunded on the spot for valid complaints;

- Warranty policy: 1-3 years warranty for the whole machine (according to the model), lifetime costprice spare parts supply.

Project Support from TAILI Electric

TAILI Electric combines transformer supply with a wider portfolio of switchgear and substation equipment. Our three-phase oil-immersed power transformers can be reviewed against the project single-line diagram and procurement specification.

◆ Electrical-equipment manufacturing experience: TAILI’s company history begins in 1988 and records a specialized transformer business from 2000.
◆ Configuration review: Voltage ratio, capacity, vector group, impedance, tap changer, cooling and accessory requirements are aligned before the final design is approved.
◆ Factory testing: Testing covers winding resistance, voltage ratio, vector group, impedance, losses and dielectric performance. Temperature-rise and lightning-impulse tests are addressed through the agreed test programme as required.
◆ Equipment coordination: Transformer and switchgear interfaces can be considered together when defining the supply scope for an industrial or utility substation.

FAQ

What is a 35kV oil immersed power transformer used for?

It is used to step up or step down voltage in medium and high-voltage power systems such as substations, factories, and utility grids.

Can you customize transformer specifications?

Yes. Voltage, capacity, winding material, cooling method, tap changer, and accessories can all be customized.

Which standards can the transformer meet?

We can manufacture according to IEC, ANSI, GB, and other required international standards.

What cooling methods are available?

Standard options include ONAN and ONAF depending on transformer capacity and project requirements.

Request a Project-Specific Power Transformer Quotation

Send your single-line diagram, required MVA, HV/LV voltages, frequency, vector group, impedance, tap-changer requirements, cooling method and site conditions. Include the accessory schedule, quantity, delivery destination and required test documentation so TAILI can review the configuration and prepare a quotation.

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