Varelen Electric Co., Ltd

7500kva Oil Immersed Transformer

Specific anti-corrosion coating  C5-M and use of stainless steel bolts to withstand the most extreme environmental condition

7500kva Oil Immersed Transformer

Related product parameters

Main Specification
Transformer Type Oil immersed
Rated capacity up to 20mva
Rated voltage up to 36kv
Frequency 50/60Hz
Phase 3 Phase
Winding material Copper /Aluminum
Tap changer Off-load or on-load
Vector group YNd1d1, Dyn11

Ambient temperature

-20°C  + 40°C
Dielectric fluids Mineral oil / Dimethyl Silicone/ Vegetable Oil/


Oil level gauge

Transformer tank

pressure relief valve

Tap changer

Oil Thermometer



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 specialized tests to meet all customer requirements. We make what matters work for our customers in a safe and reliable way.

7500kva distribution transformer

Routine test

  •  Measurement of winding resistance
  •  Measurement of voltage ratio and check of phase displacement
  •  Measurement of short-circuit impedance and loss
  •  Measurement of no-load loss and current
  •  Dielectric routine tests
  •  Tests on on-load tap-changers, where appropriate
  •  Leak testing with pressure for liquid-immersed transformers(tightness test)
  •  Tightness tests and pressure tests for tanks for gas-filled transformers
  •  Check of the ratio and polarity of built-in current transformers
  •  Check of core and frame insulation for liquid immersed transformers with core or frame insulation

 Type test

  •  Temperature-rise type test
  •  Dielectric type tests
  •  Determination of sound level for each method of cooling for which a guaranteed sound level is specified
  •  Measurement of the power taken by the fan and liquid pump motors
  •  Measurement of no-load loss and current at 90% and 110% of rated voltage

 Special Test

  •  Dielectric special tests
  •  Winding hot-spot temperature-rise measurement
  •  Determination of capacitances windings-to-earth, and between windings
  •  Measurement of dissipation factor(tanδ) of the insulation system capacitances
  •  Determination of transient voltage transfer characteristics
  •  Measurement of zero-sequence impedance(s) on three-phase transformers
  •  Short-circuit withstand test
  •  Measurement of d.c. insulation resistance each winding to earth and between windings
  •  Vacuum deflection test on liquid immersed transformers
  •  Pressure deflection test on liquid immersed transformers
  •  Vacuum tightness test on site on liquid immersed transformers

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