Oil immersed transformers


Pad mounted transformer

Use vegetable oil is that it is not flammable, reducing the risk of fire
  • distribution transformer 2500kva
  • pad mounted transformers
  • 2500kva transformers
  • oil immersed power transformer
  1. distribution transformer 2500kva
  2. pad mounted transformers
  3. 2500kva transformers
  4. oil immersed power transformer

Low noise solution

Designed and manufactured bespoke with top or side connections

Use vegetable oil is that it is not flammable, reducing the risk of fire

Environmental friendly

Vegatable oil /Mineral oil


Customized design

Our product advantages

  • Iron core

    Iron core

    The three-limb iron core is made of oblique cut Grain-oriented, seven-step silicon steel laminations insulated on both sides, guaranteeing low losses and low noise. These values are even improved by laser treatment. It is protected on the surface with a flash-proof varnish in order to prevent the sheet from corrosion and to reduce the noise. 

  • Winding


    The windings are made of oxygen-free copper , so the load loss of is lower and the electric performance is better.

  • Tank


    The transformer is fully sealed, which ensures the stability of oil quality, extends the service life,  maintenance. At the same time, the tank composed of corrugated radiator adopts phosphating and multi-layer anti-rust spraying technology to produce, which has good weather resistance.

Related product parameters

Main Specifications
Transformer typeOil-immered type
PhasesThres phases or single phases
Capacity30 - 31500kva (customization is available)
Voltageup to 36kv
Oil preservationHermetically Sealed/ Conservator/ Free Breathing
Tap changeroff-load or on-load
Winding material Aluminum/ copper
Coolerscorrugated wall or radiator
Cooling modeONAN /ONAF/ KNAN
Dielectric fluids
Mineral oil / Dimethyl Silicone/ Vegetable Oil
Impedance4% to 8%
 Lossesaccording to customers requirements
Vector groupsDyn11, Yyn11 (according to customers requirements)
StandardIEC, ANSI
 Installation locationwithout fire, explosion danger, serious foul, chemical corrosion, or violent vibration. Indoor And outdoor.

Factory Test

For each transformer are prepared and issued a test report, in accordance with IEC 60076.  except for routine tests, we also offer type tests and specialised tests to meet all customer requirements. We make what matters work for our customers in a safe and reliable way.

 Routine test

 a) Measurement of winding resistance

 b) Measurement of voltage ratio and check of phase displacement

 c) Measurement of short-circuit impedance and loss

 d) Measurement of no-load loss and current

 e) Dielectric routine tests

 f) Tests on on-load tap-changers, where appropriate

 g) Leak testing with pressure for liquid-immersed transformers(tightness test)

 h) Tightness tests and pressure tests for tanks for gas-filled transformers

 i) Check of the ratio and polarity of built-in current transformers

 j) Check of core and frame insulation for liquid immersed transformers with core or frame insulation

 Type test

 a) Temperature-rise type test

 b) Dielectric type tests

 c) Determination of sound level for each method of cooling for which a guaranteed sound level is specified

 d) Measurement of the power taken by the fan and liquid pump motors

 e) Measurement of no-load loss and current at 90% and 110% of rated voltage

 Special Test

 a) Dielectric special tests

 b) Winding hot-spot temperature-rise measurement

 c) Determination of capacitances windings-to-earth, and between windings

 d) Measurement of dissipation factor(tanδ) of the insulation system capacitances

 e) Determination of transient voltage transfer characteristics

 f) Measurement of zero-sequence impedance(s) on three-phase transformers

 g) Short-circuit withstand test

 h) Measurement of d.c. insulation resistance each winding to earth and between windings

 i) Vacuum deflection test on liquid immersed transformers

 j) Pressure deflection test on liquid immersed transformers

 k) Vacuum tightness test on site on liquid immersed transformers


Varelen offers a complete range of power and distribution transformers designed to grant the reliability, durability, and efficiency required in utility, industrial,and commercial applications. Our oil-immersed transformers are manufactured in accordance with the most demanding industry and international standards. Transformers can be used for indoor or outdoor applications and can be provided with off-load and on-load tap changers.

Related Content

Oil immersed transformer

Oil immersed transformer

Conservator Type Transformer

Conservator Type Transformer

Special Distribution Transformers

Special Distribution Transformers


Contact us

Varelen Electric Co., Ltd

Information submitted... Later, please