What Are 11kV Oil Immersed Distribution Transformers?

11kV oil immersed distribution transformers are three-phase transformers designed to step down medium voltage (typically from 11kV to 400V–433V) for use in local distribution systems. These transformers utilize mineral or biodegradable insulating oil for both cooling and insulation, providing reliable performance in industrial, commercial, and utility environments.

They are a critical component in power distribution networks, ensuring stable voltage supply to buildings, factories, and public infrastructure.

Why Use 11kV Oil Immersed Distribution Transformers?

High Efficiency

Built with low-loss cold-rolled silicon steel cores and precision-wound copper or aluminum windings, these transformers meet or exceed energy efficiency standards such as IEC 60076 and DOE 2016. Lower core and load losses translate to reduced operating costs over time.

Long Service Life

With a sealed tank design, high-quality insulation materials, and anti-corrosion treatment, CHBEB 11kV transformers are built for durability—delivering 20 to 30 years of stable operation even in outdoor or high-humidity environments.

Flexible Configurations

Available across a wide range of power ratings (50kVA–2500kVA) and customized for various installation types (pole-mounted, pad-mounted, or ground-based). Easily matched with systems in:

• 11kV Series

• 15kV up to 36kV Series

Key Features of 11kV Oil Immersed Distribution Transformers

Core and Windings

High-permeability silicon steel cores combined with high-conductivity copper or aluminum windings minimize both no-load and load losses.

Cooling System

Standard ONAN (Oil Natural Air Natural) cooling system with optional ONAF (forced-air cooling) for larger capacities. Corrugated tanks or radiators enhance thermal performance.

Protection and Safety

Equipped with essential protection components: Buchholz relay, pressure relief valve, oil level indicator, thermometer, and optional lightning arresters or OLTC (on-load tap changer) for improved voltage regulation.

Noise Reduction

Engineered for quiet operation (<55–60 dB at 1 meter), making them suitable for installations near residential areas or commercial zones.

Eco-Friendly Options

Biodegradable insulating oils and hermetically sealed tanks available to reduce environmental impact and eliminate oil leakage risks.

Applications of 11kV Oil Immersed Distribution Transformers

• Industrial Facilities and Manufacturing Plants

• Residential Communities and Office Buildings

• Hospitals, Schools, and Commercial Complexes

• Solar and Wind Power Distribution Systems

• Rural and Urban Utility Distribution Networks

Standards and Compliance

• Design Standards: IEC 60076, ANSI/IEEE C57.12, GB, AS, CSA

• Testing: 100% routine testing according to IEC; optional type and special tests available

• Certifications: CE, ISO9001, ISO14001, ISO45001, RoHS (optional)

Advantages of CHBEB 11kV Oil Immersed Transformers

• Proven Low-Loss Performance

• Reliable in Harsh Climates

• Customizable Ratings and Tappings

• Compact and Easy to Install

• Economical Long-Term Operation

Choose CHBEB

Choose CHBEB 11kV oil immersed distribution transformers for a dependable, energy-efficient, and long-lasting solution. With over 60 years of transformer manufacturing expertise, CHBEB supports utility, industrial, and EPC projects across Asia, Africa, the Middle East, and beyond.

👉 Need technical specs or drawings?
Browse by voltage level:

• 11kV Series

  Capacity (kVA)	Voltage Combination			Vector group	No-load loss (W)	Load loss (W) (75°C)	Impedance voltage (%)	No-load current (%)
  	HV	Tapping range of HV	LV
  25	6 kV 6.6Kv 10.5kV 11kV	±5%,±2×2.5%	0.38 kV 0.4 kV 0.415 kV 0.48 kV	Yyn0 Dyn5 Dyn11	100	600	4.0	1.7
  50					130	870		1.6
  63					150	1040		1.5
  80					180	1250		1.4
  100					200	1500		1.3
  125					240	1800		1.2
  160					280	2200		1.1
  200					340	2600		1
  250					400	3050		0.9
  315					480	3650		0.9
  400					570	4300		0.8
  500					680	5100		0.8
  630					810	6200	4.5	0.7
  800					980	7500		0.6
  1000					1160	10300		0.55
  1250					1360	12000		0.5
  1600					1640	14500		0.45
  2000					1940	18500	5.5	0.4
  2500					2300	20500		0.4

   

• 15kV up to 36kV Series

  Capacity (kVA)	Voltage Combination			Vector group	No-load loss (W)	Load loss (W) (75°C)	Impedance voltage (%)	No-load current (%)
  	HV	Tapping range of HV	LV
  630	13.2kV 13.8kV 15 kV 20 kV 22 kV 33 kV 34.5 kV	±5%,±2×2.5%	0.38 kV 0.4 kV 0.415 kV 0.48 kV	Yd11	1150	6200	4.5	0.9
  800					1400	7500	5.5	0.8
  1000					1650	10300		0.7
  1250					1950	12800		0.6
  1600					2300	14500		0.6
  2000					2650	17100		0.6
  2500					3100	20000		0.6
  3150					3650	23700		0.5
  4000					4450	28100		0.5
  5000					5200	32700		0.5
  6300					6150	36900		0.5
  8000					8900	44000		0.4
  10000					11600	50600	6.5	0.4

Or contact us directly for quotations, custom designs, or consultation with our technical team.