11 kV Transformer Factory & Manufacturer
Subian Electric manufactures distribution transformers for 11kV networks – the standard medium-voltage level in the UK, Ireland, Malaysia and many other markets. Our range covers oil-immersed and dry-type units from small pole-mounted ratings upward, engineered for 11kV/400V and 11kV/433V duty.
Built at our 50,000-square-metre factory in Xuzhou with 350+ employees, each unit is routine-tested and delivered with drawings and a test report, backed by export experience to more than 50 countries since 2019.
Send your rating, secondary voltage (400V or 433V) and installation type, and our engineers will confirm the design and factory quotation.
Since 2019 · 50,000m² · 350+ Staff
11 kV Distribution Transformers We Build
Oil-immersed and dry-type transformers for 11kV systems – pole-mounted, ground-level and substation units from 25 kVA upward with 400V or 433V secondaries.
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10kV Dry-Type Transformer-SCBH series Amorphous Alloy
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20-35KV Dry-Type Transformer
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20-35KV SCB Series Epoxy Resin Dry-Type Transformer
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20KV Oil-immersed Distribution Transformer
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35KV Oil-immersed Power Transformer
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6-10KV Oil-Immersed Power Distribution Transformer
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Current Transformer –10KV Indoor High Voltage
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Current Transformer–LMZK Wound Current Transformer300/5a
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Current Transformer–LSY-10 transformer Integrated CT
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current transformer–LXK high voltage zero sequence
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dry type distribution transformer-6-10 KV SCB series epoxy resin cast
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Electrical Transformers–JDZ – 10 Power Voltage
What Is an 11 kV Transformer?
An 11 kV transformer is a distribution transformer whose primary connects to an 11kV network and whose secondary feeds the low-voltage system – usually 400V/230V three-phase, with 433V still found where older networks predate the standardisation to 400V. It is the workhorse of electricity distribution in the UK and Commonwealth markets.
The rating is selected from the peak load and growth of the served area, and the ratio and vector group are set by the network operator’s standard. Because 11kV is a distribution level, the emphasis is on low losses, reliable sealing against weather and moisture, and easy replacement within an existing network.
- 11/0.4kV & 11/0.433kV – ratios matched to UK and Commonwealth practice.
- 25 kVA upward – pole, ground and substation installations.
- Oil-immersed standard – dry-type available for indoor duty.
- Low-loss designs – options from conventional to amorphous core.
- Routine-tested – each unit issued with its test report.
- Export experience – 11kV networks served across 50+ countries.
Installation Types
The network layout decides the unit type:
Pole-mounted
small ratings (typically 25-100 kVA) for rural overhead networks.
Ground-level / plinth
medium ratings for villages, farms and small commercial loads.
Substation type
larger units inside compact substations and distribution buildings.
11 kV Transformer Technical Data (Typical)
| Parameter | Specification |
|---|---|
| Rated capacity | 25 – 2,500 kVA (typical range) |
| Primary voltage | 11 kV |
| Secondary voltage | 400 V / 230 V or 433 V |
| Vector group | Dyn11 / Dyn1 |
| Cooling | ONAN (oil) / air (dry) |
| Frequency | 50 Hz |
| Standard | IEC 60076 / BS EN 50464 |
Choosing the Rating and Checking Full-Load Current
To size an 11kV distribution transformer, add the connected load in kW, apply the expected diversity, divide by the power factor, and add margin for motor starting and growth. Common ratings on 11kV networks are 100, 200, 250, 315, 500 and 630 kVA, with smaller pole units at 25-100 kVA.
The full-load current on the 11kV side is small – about 5.2 A per 100 kVA – while the 400V secondary carries roughly 144 A per 100 kVA. These figures set the fuse or breaker ratings and the LV cable sizes downstream.
Indicative currents at common ratings (11/0.4kV)
| 100 kVA | primary approx. 5.2 A · secondary approx. 144 A |
|---|---|
| 250 kVA | primary approx. 13.1 A · secondary approx. 361 A |
| 500 kVA | primary approx. 26.2 A · secondary approx. 722 A |
| Real load at 0.8 pf | kW = kVA x 0.8 |
Replacement of an Existing 11kV Transformer
When replacing a failed unit, collect the nameplate data and, if possible, the old outline drawing: primary and secondary voltage, vector group, impedance, tapping range, and the physical mounting and terminal arrangement.
With that data we match the new unit to the network’s protection settings and the existing structure. Where only part of the data is available, our engineers can work from the network standard and measurements taken on site.
Building an 11kV Transformer for Export
Core, winding, drying, oil filling and testing are carried out in-house so the 11kV unit matches the ordered ratio and loss specification, with documentation prepared for the destination network.
Winding & Core
Coils are wound for the 11kV ratio with controlled insulation and tapping range.
Vacuum Drying
Careful drying protects the insulation before oil filling or resin casting.
11 kV Transformer Price & Quotation
Request a factory quotation with your rating, secondary voltage and installation type. We confirm the ratio, losses and outline drawing before production, and single units and programmes are both supported.
OEM / ODM & Wholesale Supply
Distributors serving 11kV networks can take transformers under their own brand with local-standard documentation.
OEM / ODM
Factory-Direct
Private-label units with network-standard ratios and packaging.
Factory direct · Test docs · Export support
Wholesale Supply
Volume Pricing
Stock programmes for distributors serving 11kV areas.
Factory direct · Test docs · Export support
Distributor Support
Channel Partners
Technical data and tender documentation for channel partners.
Factory direct · Test docs · Export support
11 kV vs Other Distribution Voltages
11kV is one of several medium-voltage levels; 10kV dominates in many countries, 20kV in parts of Europe, and 33kV for higher-capacity feeders. The equipment for each class is similar in principle but differs in insulation levels, clearances and cost.
For a buyer in an 11kV market the decision is not the voltage – it is already set by the network – but the transformer quality, losses and documentation. If a project spans two voltage levels, transformers and switchgear for both can be supplied together from the same factory.
Choosing an 11 kV Transformer Supplier
Compare the guaranteed loss values, the sealing and corrosion protection for outdoor duty, and the type-test evidence for the design. For replacement units, match the old nameplate: ratio, vector group, impedance and tapping range must fit the existing network settings.
Subian manufactures under ISO9001, ISO14001, ISO45001, CE and UL certified systems and exports 11kV-class units to markets across Asia, Africa, the Middle East and beyond, with test reports and drawings issued per order.
Confirm the supplier can provide replacement units that match existing installation footprints – outline dimensions and terminal arrangements matter as much as electrical data when swapping a failed unit.
Certifications & Quality Assurance
Our distribution transformer production runs under ISO9001, ISO14001 and ISO45001 systems with CE and UL certification and type-test evidence to 110 kV class.
Product Certifications
10 kV Dry-Type Transformer Certificate
35 kV Transformer CB Certificate
35 kV Transformer CE Verification
Transformer CE Certificate
Dry-Type Transformer Test Verification
ISO 14001 Environmental Management
ISO 45001 Health & Safety
ISO 9001 Quality Management
110 kV Transformer Type Test Report
UL Certificate of Compliance
11 kV Transformer FAQ
Common questions about 11kV transformers, their ratings and replacement.
What is an 11kV transformer?
How do you convert 11kV to 440V?
What is an 11kV potential transformer?
What is the rating of an 11kV 440V transformer?
How many amps can an 11kV transformer supply?
What voltage comes out of an 11kV transformer?
Contact Subian
Need the Right Specification?
Tell us your target market, product type, quantity and technical requirements. Our team will help you identify a suitable configuration for your project.