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3-Phase Oil Immersed Distribution Transformers

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1000kVA /33-0.41kV Oil Immersed Distribution Transformer

This Taili transformer is an oil-immersed distribution transformer equipped with separable high-voltage bushings. The HV side is designed for plug-in cable connection, while the LV side uses copper busbars, ensuring safe operation, easy installation, and reliable performance.

This type of Oil Immersed Transformer is widely used in underground cable distribution systems, modern power networks which require high safety and flexible installation.

The transformer complies with IEC 60076 standards.

As a professional transformer manufacturer and global supplier, we provide customized solutions for importers, EPC contractors, distributors, and power utility projects worldwide.

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3-Phase Oil Immersed Distribution Transformer Manufacturer | Reliable Power Transformer Supplier

Our 3-Phase Oil Immersed Distribution Transformers are engineered for efficient and stable power distribution across utility grids, industrial plants, commercial buildings, renewable energy systems, and infrastructure projects. Designed with advanced insulation systems and high-quality transformer oil cooling technology, these transformers ensure dependable voltage conversion, low operating losses, and long service life.

TAILI’s 1000kVA 33kV oil-immersed distribution transformer is designed to step down 33kV medium-voltage power to 410V for industrial facilities, utility distribution networks and infrastructure projects. The standard configuration uses a Dyn11 vector group, 6% impedance and an off-circuit tap range of ±2 × 2.5%.

Voltage ratio, winding material, terminal arrangement, tank structure, accessories and applicable standards can be adjusted to match the project specification.

Primary Voltage	33kV
Secondary Voltage	410V
Vector Group	Dyn11
Impedance	6%
Capacity (Power Rating)	1000kVA
H.V. Tap Range	±2 × 2.5% or others
BIL (Basic Insulation Level)	30–150 kV
Standards	IEC, IEEE, ANSI, DOE
Certificates	CE, SGS, ASTA

We supply oil immersed distribution transformers for a wide range of power distribution projects, including:

Standard Distribution Series

Commonly used in 10kV / 20kV networks, featuring fully sealed tank designs and compact installation advantages.

Medium Voltage Step-Down Series

Typical models include:

· 11kV to 400V transformer
· 11kV to 0.4kV transformer
· 20kV to 400V transformer

Suitable for industrial and utility power systems.

Designed for 33kV Distribution Projects

33kV / 35kV Transformer Series

Designed for heavier-duty power distribution and substation applications with wider capacity coverage.

Reliable Voltage Conversion

The 33kV/410V configuration supplies stable low-voltage power for production equipment, building services and local distribution systems. The Dyn11 connection is suitable for common three-phase distribution networks and helps manage unbalanced low-voltage loads.

Low-Loss Core and Winding Design

The magnetic core and winding structure are engineered to control no-load loss, load loss and operating temperature. Exact guaranteed loss values are confirmed in the approved technical datasheet before production.

Strong Insulation and Cooling Performance

Transformer oil provides both electrical insulation and heat dissipation. The insulation level, clearances and cooling design are selected according to rated voltage, ambient temperature, altitude and expected loading conditions.

Project-Specific Configuration

TAILI can adjust the transformer design for different grid and installation requirements, including:

· Alternative secondary voltages
· Copper or aluminum windings
· Custom vector groups and impedance
· Hermetically sealed or conservator tank design
· Cable boxes or project-specific terminal arrangements
· Corrosion-resistant paint systems
· Temperature, oil-level and pressure monitoring accessories

Main Features of 3-Phase OilImmersed Distribution Transformer

1. Enhanced Insulation Performance

Compared with traditional porcelain bushings, the separable bushing design provides superior insulation performance.

2. High safety design
The transformer is fully insulated structure, suitable for enclosed or underground installations.

3. Copper busbar on LV side
It is low loss and reliable connection.

4. Sealed oil-immersed structure
Very good heat dissipation and long service life.

5. Easy installation and maintenance
Ideal for compact substations and modern distribution systems.

3-Phase Oil Immersed Distribution Transformer Construction

The core and windings operate inside an oil-filled tank. Cooling surfaces, insulated terminals and specified protective accessories complete the assembly. The final layout and accessory list depend on the approved construction.

Component	Function and Design Considerations
Iron core	Provides the magnetic path for voltage transformation. Core material, lamination quality and joint construction influence no-load loss, excitation current and operating noise.
HV and LV windings	Insulated conductors form the primary and secondary circuits. Copper or aluminum conductors can be specified, with insulation and mechanical support matched to the electrical design.
Oil tank	Houses the core, windings and insulating oil. Tank seals protect the oil system, while the surface coating is selected for the site environment. The expansion arrangement depends on the specified tank design.
Radiators and cooling surfaces	Transfer heat from circulating oil to the surrounding air. Corrugated tank walls or separate radiator assemblies are selected according to construction and thermal requirements, with sufficient space for airflow.
Bushings and terminals	Carry electrical connections through the tank while maintaining insulation. On the featured model, separable HV bushings support plug-in cable termination, and LV copper busbars provide the low-voltage connection.
Tap changer	Changes the effective winding turns to adjust the voltage ratio. The reference off-circuit tap changer is operated only with the transformer de-energized and safely isolated.
Pressure-relief device	Releases excessive internal pressure when its operating threshold is reached. Device type, setting, mounting position and any required alarm contacts should be identified in the agreed accessory schedule.

Key Advantages for Distribution Projects

Low No-Load Loss

The magnetic core is designed to limit losses whenever the transformer is energized, including during light-load periods. Buyers should compare guaranteed no-load and load-loss values separately, using the expected operating hours and load profile to assess long-term energy costs.

Efficient Oil Cooling

Insulating oil carries heat from the active parts to the tank cooling surfaces or radiators. In an ONAN configuration, natural oil and air circulation dissipate heat without cooling fans or oil pumps. The cooling arrangement is selected to meet the specified loading and temperature-rise requirements.

Strong Insulation Performance

Transformer oil and solid insulation work together to electrically separate the windings, core and tank. Insulation coordination considers rated voltage, expected network surges and site conditions. Required dielectric withstand levels and verification tests should be defined in the project specification.

Stable Operation Under Cyclic Loads

The thermal design can be matched to repeated daily load changes in industrial and utility service. Share peak demand, peak duration, recovery periods and ambient temperature so the rating and cooling system can be assessed against winding hot-spot and top-oil temperature limits.

Low Maintenance

A sealed tank configuration limits contact between insulating oil and ambient air, helping control moisture ingress and oil oxidation. Routine care includes checking seals, bushings, connections and monitoring accessories, with oil testing and other service tasks scheduled according to the operating conditions and maintenance instructions.

Outdoor Installation Suitability

Tank sealing, protective coatings and terminal arrangements can be specified for outdoor distribution projects. Site review should cover rainfall, pollution, coastal corrosion, ambient temperature and altitude, together with the foundation, cable approach and cooling clearances. Outdoor suitability is confirmed for the agreed configuration.

Low Loss Three-phase Oil-immersed Distribution Transformer Production

01 Oil transformer production equipment

3-Phase OilImmersed Distribution Transformer

02 Assembly workshop of oil immersed transformer

3-Phase OilImmersed Distribution Transformer

03 Ex-factory test for oil transformers

1000kVA /33-0.41kV Oil Immersed Distribution Transformer

04 Accessories of Oil-Immersed Transformer

1000kVA /33-0.41kV Oil Immersed Distribution Transformer

Application scenarios

Power transmission and distribution networks

They handle voltage conversion between 35/33/22/20/15/13.8/11 kV networks and secondary distribution levels such as 400/230 V.

Industrial

Industrial parks ，manufacturing plants，Oil, gas, and mining projects，Data centers and telecommunication stations

Commercial and civil buildings

The power distribution system of high-rise buildings, shopping malls, and hospitals is directly installed in the low-voltage distribution room and provides 0.4kV power supply.

Package and Shipping

3-Phase OilImmersed Distribution Transformer

WHY CHOOSE TAILI?

◆ Customized electrical and mechanical design
◆ IEC, IEEE and market-specific engineering support
◆ Routine testing before shipment
◆ Technical drawings supplied for project approval
◆ Export packaging for long-distance transportation
◆ 2–3 year product quality warranty
◆ Remote technical support for installation and commissioning

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: 2-3 years warranty for the whole machine (according to the model), lifetime costprice spare parts supply.