1.Modifications referred to the exemptions

  • The Regulation EU 548/2014 apply to transformers for photovoltaic applications  and windmills.
  • Traction transformers  are excluded from the Eko regulation

2.Modifications referred to the definitions

  • A medium power transformer definition referes to each transformer  up to 3150 kVA with insulation class up to 36 kV
  • A large power transformer definitione referes to each transformer with power higher than 3150 kVA with insulation class over 36 kV.
  • Due to different country technical specification in case of Czech Republic  24 kV and 36 kV are replaced by respectively 25 kV and 38,5 kV.
  • In case of pole-mounted transformers the power range has been extended also to 400 kVA.

3.Modifications referred to repairs

In case of repair (replacement of one or more coils or core) the regenerated transformer must still comply with the eco design requirements.

4.Update of Tables

There are no changes in reference to the insulation class up to 24 kV. In case of insulation class 36 kV there are following corrections must be applied:

Table I.3: Correction of load and no load losses in case of other combinations of winding voltages or dual voltage in one or both windings (rated power ≤ 3 150 kVA)

  • Small size installation room
  • Poorly ventilated installation room
  • Medium daily temperature higher than 30°C

Please consider that medium operation life of each ventilation system is around 20.000 hours. The life of your cast resin transformer are 25 -30 years. Make sure to maintain the cooling fans correctly and to replace them in time, if necessary.

Forced ventilation can be fitted at Manufacturer’s works or after installation of the transformer at site. Please consult Figures 11 and 12 and Table 3 different models capacity and dimensions.

5.New PEI calculation formula

 The methodology for calculating the Peak Efficiency Index (PEI) for medium and large power transformers is based on the ratio of the transmitted apparent power of a transformer minus the electrical losses to the transmitted apparent power of the transformer.

P0 is the no load losses measure at rated voltage and rated frequency, on the rated tap
Pc0 is the electrical power required by the cooling system for no load operation
Pk is the measured load loss at rated current and rated frequency on the rated tap corrected to the reference temperature
Sr is the rated power of the transformer or autotransformer on which Pk is based

The new PEI calculation formula takes into the consoderation also the power taken by the fans at the load at which the PEI is calculated. Please consider also that the tables indicating PEI values have been extended to very low and very high powers.


The manufacturer is obliged to provide documentation relating to the exemption of the product from the legislation and indicate the reason for this exemption. The manufacturer remains responsible for the application of the legislation with reference to the supply of his products within the European community.

For further information do not hesitate to get in touch with our POWER Team.