Oil-Immersed & Padmount Transformers — SOTEK
📞 Hotline: +84 903.219.753 | 📧 Email: infor@sotekvietnam.com | 📍 Plant: Tien Son Industrial Park, Tu Son, Bac Ninh, Vietnam
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Liquid Insulated

Oil & Padmount

Premium grade cooling oil distribution designs for urban grids, overhead lines, and commercial zones.

Sealed-Type Distribution

Oil Immersed 3-Phase — Sealed-Type

SOTEK’s sealed-type three-phase oil-immersed distribution transformers feature a corrugated tank design where the cooling fins expand and contract dynamically with oil temperature changes, eliminating the need for an external conservator. This compact structure reduces installation footprint and protects the insulating oil from ambient oxygen and moisture, extending maintenance intervals.

Constructed with low-loss CRGO steel cores and high-purity copper windings, these units operate under the standard 96/QĐ-HĐTV utility guidelines. Fully tested to IEC 60076 and TCVN 6306 standards for optimal heat dissipation and high short-circuit withstand capabilities.

SOTEK Oil Immersed - 3 Phase Sealed Transformer
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Technical Specifications

Parameter Specifications
Power Rating Up to 16 MVA
Voltage Class Up to 40.5 kV
Cooling Type ONAN / ONAF (optional KNAN, KNAF)
Core Material Cold-rolled grain-oriented silicon steel or amorphous alloy (on request)
Winding Material Copper / Aluminium
Insulation Liquid Mineral oil / Natural ester
Protection Mode Hermetically sealed corrugated tank
Tap Changers Customizable DETC / OLTC
Standard Compliance IEC, ANSI, TCVN compliant
Conservator Tank Distribution

Oil Immersed 3-Phase — Unsealed-Type

SOTEK’s unsealed-type three-phase distribution transformers are equipped with a dedicated conservator (expansion) tank. This classic configuration allows the main transformer tank to remain fully filled with oil, while any thermal expansion is absorbed by the conservator. It is fitted with gas-operated relays (Buchholz) for early fault detection and silica gel dehydrating breathers to remove moisture from incoming air.

Offering easy access for oil sampling, level inspections, and maintenance, these transformers are highly favored for heavy industrial plants and utility substations. Designed and verified under standard 96/QĐ-HĐTV, IEC 60076, and TCVN regulations.

SOTEK Oil Immersed - 3 Phase Unsealed Transformer
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Technical Specifications

Parameter Specifications
Power Rating Up to 16 MVA
Voltage Class Up to 40.5 kV
Cooling Type ONAN / ONAF (Forced air options)
Core Material Cold-rolled grain-oriented silicon steel or amorphous alloy (on request)
Winding Material Copper / Aluminium
Insulation Liquid Mineral oil / Natural ester
Protection Mode Unsealed with conservator (expansion) tank
Tap Changers Customizable DETC / OLTC
Standard Compliance IEC, ANSI, TCVN compliant
Ultra-Low Loss Core

Amorphous Core – 3 Phase

SOTEK’s three-phase amorphous alloy core distribution transformers represent the pinnacle of grid efficiency. By utilizing an amorphous metal alloy core instead of conventional grain-oriented silicon steel, these units reduce no-load losses (core losses) by up to 70% to 80%.

This technological leap provides significant savings in operating costs over the transformer’s lifespan and drastically lowers greenhouse gas emissions, making it ideal for solar/wind farms, smart grids, and green building projects.

SOTEK Amorphous Core - 3 Phase Transformer
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Technical Specifications

Parameter Specifications
Power Rating Up to 16 MVA
Voltage Class Up to 40.5 kV
Core Material Amorphous metal core (Fe-B-Si ribbon)
Winding Material Copper / Aluminium
Cooling Type ONAN / ONAF
Insulation Liquid Mineral oil / Natural ester (FR3)
Protection Mode Hermetically sealed or with conservator tank
Loss Efficiency 70% – 80% reduction in no-load loss
Standard Compliance IEC 60076, TCVN, IEEE compliant
Overhead Utilities

Single-Phase Pole-Mount

Designed for rural electrification and localized grid extension, these single-phase overhead transformers feature high mechanical durability and withstand severe weathering.

Housed in mild steel cylindrical corrugated tanks with wet-process porcelain primary bushings, SOTEK overhead units offer low-impedance configurations and robust fault protection.

SOTEK 1-Phase Pole-Mount Transformer
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Technical Specifications

Parameter Specifications
Capacity Range 15 kVA – 500 kVA
Voltage Class Up to 40.5 kV class
Frequency 50 Hz / 60 Hz
Core Construction Wound CRGO core loop
Bushings Wet-process cover porcelain bushings
Safety Feature Pressure relief valve, arrestor bracket
Standard Compliance ANSI C57.12.20, IEC 60076
Underground Integrated Substation

Padmount Transformers

Built for underground power grids in commercial towers and residential areas, SOTEK’s new padmount series features compartmentalized HV/LV layout, providing complete safety for public access areas.

The cabinet enclosure is tested to ANSI C57.12.28 tamper-resistant standards. Units can be configured with dead-front elbow connectors, bay-o-net fuse protection, and loop or radial-feed switch mechanisms.

Padmount Transformer
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Technical Specifications

Parameter Specifications
Capacity Range 75 kVA – 5,000 kVA
Voltage Class Up to 35 kV class
Compartments Separate HV & LV cable chambers, lockable door
Connector Interface Dead-front (HV elbow) / Live-front option
Grid Feed Type Loop feed / Radial feed
Fluid Insulation Mineral Oil / Biodegradable FR3 Fluid
Standard Compliance IEEE C57.12.34, ANSI C57.12.28