A cast resin transformer  is a type of transformer that has outstanding features not use liquid to cool the coil but by air.

To make sure the quality and safety operation of the transformer, Users need to check and test them before operation and after operating for a long time. Tests help users easily detect some signs of damage.


Types of Cast Resin Transformer Testing

1. Routine Test

2. Type Test

3. Special Test

Routine Tests of Cast Resin Transformer Transformer

  • Auxiliary wiring insulation test
  • Dielectric routine tests
  • Voltage ratio Test
  • Transformer Ratio Test
  • Tests on-load tap changers
  • Winding resistance measurement
  • No-load loss and current measurement
  • Short-circuit impedance and load loss measurement
  • Phase displacement test
  • PD Measurement
  • Insulation test and functional verification of accessories

Type Tests of Cast Resin Transformer Transformer

  • Temperature-rise type test (IEC 60076-2)
  • Dielectric-type tests (IEC 60076-3)
  • Sound level test (IEC 60076-10) for each method of cooling for which a guaranteed sound level is specified
  • No-load loss and current measurement at 90% and 110% of the rated voltage
  • Measurement of the power taken by the fan

Special Tests of Cast Resin Transformer Transformer

  • Dissipation factor measurement (tan δ) of the insulation system capacitances
  • Winding hot-spot temperature-rise measurements
  • Dielectric special tests (IEC 60076-3)
  • Determination of capacitances windings-to-earth and between windings
  • Short-circuit withstand test
  • Verification of the climatic classes
  • Detection of harmonic content in the no-load current
  • Determination of transient voltage transfer characteristics
  • Zero-sequence impedance(s) measurement on three-phase transformers
  • Frequency response Measurement (Frequency Response Analysis or FRA); the test procedure shall be agreed between manufacturer and purchaser
  • D.C. insulation resistance measurement between each winding to earth and between windings
  • Winding inductance measurement
  • Check of external coating (ISO 2178 and ISO 2409 or as specified)
  • Determination of weight with transformer arranged for transport for transformers up to 1,6 MVA by measurement; for larger transformers by measurement or calculation as agreed between manufacturer and purchaser
  • Thermographic detection of hot-spots
  • Verification of the behavior to fire classes
  • The transmitted vibrations measurement
  • In-rush surges test
  • Verification of the environmental classes
  • Test on vibration floor (seismic)
  • Recurrent voltage surges test
  • Low-temperature test



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