Middle voltage transformers

Transformers are devices that convert alternating current electricity from one voltage level to another by means of a magnetic field, without changing the frequency of the voltage. The selection of the transformer and the calculation of its characteristics are based on nominal quantities.

Transformers are used mainly where it is necessary to increase the voltage, in order to reduce the current, e.g. in power plants or to reduce the voltage to reduce the current e.g. substations and welding machines. The transformer must ensure an uninterrupted supply of electricity to consumers. For this reason, the amount and power of the transformers must be chosen correctly at the design, it has to be technically and economically justified. To ensure reliability, it is necessary to take into account the nature of the consumer, when choosing a transformer.

We offer in our product range both oil and epoxy resin insulation transformers.

CAST RESIN transformers

Cast resin transformers are distribution, industrial and they have at least one of the two windings embedded on an autoclave mould, at vacuum values ​​close to zero with epoxy resin. The other winding can also be cast in epoxy resin or impregnated with H class polyester resin with high cementation. Our offered cast resin transformers are suitable for indoor or outdoor applications.

Cast Resin Transformers have reached a high degree of reliability thanks to the technological advances in recent years. Transformers offered by us E2, C2, F1, but also E3 (IEC 60076-16) and C4 (GOST-R), can be used in the presence of a high humidity and pollution rate, low installation temperatures even down to -60°C, therefore eliminating the problems related to the risks of fire and emissions of toxic and harmful substances in case of fire.

As they are entirely built with insulating, flame retardant and self-extinguishing materials, they are completely free from all restrictions that should normally be applied to flammable equipment with a danger of spreading fire. These transformers can be used in substations for public buildings, hospitals, airports, and in places where usage of liquid immersed transformers is restricted for fire risk or enviroment protection, e.g. tunnels, marine, cranes, offshore platforms, wind turbines, groundwater catchment areas and food processing plants.
Outdoor solutions can be realized with a wide range of boxes.

Special technical executions can be realized according to the customer’s requests:

  • On Load Tap Changer (OLTC)
  • Double or multiple tier execution
  • Multi secondary windings arrangement
  • Special cable output from enclosures
  • Different type of cooling (AN-AF-AFWF)
  • Rated power up to 30 MVA
  • Insulation level up to 52 kV
  • Nominal frequency 50 or 60 Hz
  • Indoor installation
  • E2, C2, F1, E3, C4 certified
  • Storage and installation temperature -25 ° C to + 40 ° C (on request -60 ° C)
  • Moisture resistance up to> 95%
  • Auxiliary housing protection class up to IP54
  • Warranty 24 months


OIL IMMERSED transformers

Oil immersed transformers offer a customize and reliable solution for the customer as the typical design allows many configurations and installations. Thanks to their design, oil immersed transformers are used either for indoor or outdoor installations and in high polluted places. In this type of transformer, the magnetic circuit and the windings are immersed in an insulating liquid such as mineral, silicone, ester or vegetable oil. The choice of oil is linked to the type of installation and the specific requirement of the customer and where it is necessary to ensure special guarantees in terms of environmental impact and safety in the event of a fire. We offer three phase oil-immersed distribution transformers with rated power in range from 25 kVA up to 25,000 kVA transformers for all applications, in particular transformers for distribution and special   MV/LV, MV/MV, LV/LV, HV/MV, HV/LV and HV/HV transformers with power from 50kVA up to 50 MVA, up to voltages of 145 kV (BIL 650 kV), with vacuum or load tap changer. Transformers are both types, hermetically sealed and with conservator. They are manufactured in accordance with local and international standards and fully adapted for mounting in complete transformer substations and steel-lattice poles. The windings can be made from aluminium or copper depending on customer requirements and needs.

  • Rated power up to 50 MVA
  • Insulation level up to 170 kV
  • Nominal frequency 50 or 60 Hz
  • Insulation fluid mineral oil
  • Hermetically sealed or with expansion tank
  • Normal or reduced losses
  • Ambient temperature -40 ° C to + 40 ° C (on request -60 ° C)
  • Exterior walls are protected with waterproof paint RAL 7031 or RAL 7033, with a paint thickness of at least 120 microns, which is suitable for the most severe environmental conditions
  • Installation both indoors and outdoors up to degree of protection IP54
  • High power cooling options such as ONAN, ONAF, OFAF or OFWF
  • Large selection of accessories