Hermetically sealed distribution transformers up to 3150 kVA

Hermetically sealed distribution transformers up to 3150 kVA


Distribution transformers up to 3150 kVA made by BEZ TRANSFORMÁTORY are hermetically sealed and designed for maximum insulation voltage up to 36 kV. Hermetically sealed transformers are suitable for indoor and outdoor installation and thanks to the design and material quality, the transformer's performance remains at a high level during its lifetime. The transformers are designed and manufactured in conformity with EN, IEC, DIN, and other standards.


Standard portfolio up to 3150 kVA is hermetically sealed and therefore the dielectric is not in contact with the atmosphere and there is no oxygen absorption of inner parts. This guarantees safe operation for persons same as environment, no need of oil replacement and generally low maintenance with three times longer sample period.



Transformers can be equipped with a wide range of accessories like bi-directional rollers, oil indicators, thermometers, pressure gauge, pressure relief valve, and also integrated safety detector which can control transformer’s pressure, temperature, oil level, and gassing at once on-site or remotely.


  • Ready for installation
  • Safe and reliable operation
  • Suitable for application from renewables to heavy industry
  • Energy efficiency with low operating costs
  • Ecological solution (can be combined with natural esters)


  • Rated voltage up to 36 kV
  • Rated power up to 3150 kVA
  • Corrosive protection coating
  • High vibration resistance
  • Space compactness
  • Various types of primary and secondary terminals



BEZ TRANSFORMÁTORY offers Ecodesign Tier 2 Liquid-filled Transformers that meet the requirements of No-Load and Short Circuit Loss im-posed by the new Regulation.

EU Commission Regulation 2019/1783 defines maximum No-Load and Short Circuit Loss. This Regulation applies to transformers in the market or commissioned in the EU after publishing the Regulation, of which Tier 1 began on 1 July 2015 (548/2014), and Tier 2 is valid since 1 July 2021 (EU Commission Regulation 2019/1783).

AAoAk (Ecodesign Tier 2)

Energy Efficient (average total loss 28% less than CoCk) Low Operating Costs, Eco-friendly.

Compared to standard transformers, Ecodesign transformers have lower total loss. This means that they have lower operating costs, which converts into significant cost savings throughout equipment service life.


(Ecodesign Tier 2)


Rated Power, kVA



No-Load Loss, W



Short Circuit Loss, W



Loss Cost, € per year



Note: operating costs for BEZ Oil-Filled Transformers for 30 years subject to electricity cost 0.16 Euro per 1 kWh, and transformer load factor of 0.7; 1 kWh equals to 0.513 kg of CO2

  • Total Savings €76 864 ≈ 5 x Price
  • Saving on CO2 emissions 246 Ton (480 MWh)
  • Payback term in favor of more energy-efficient transformer, due to price difference: 2 years