Cast resin transformers
Cast resin transformers represent an alternative solution for electric power distribution in medium voltage applications.
The advantages of cast resin transformers in comparison with the traditional oil-filled transformers are quite evident:
The materials used for production of cast resin transformers are hardly inflammable and can be defined as self-extinguishing, which is why there is no need to use any special fire protection coatings for this type of transformers. Furthermore, in case of fire, the emission of toxic gases and opaque fumes is very low. These advantages make cast resin transformers a perfect choice for installations at places where safety is crucial, such as hospitals, public premises, airports, subway lines, mines, oil rigs, nuclear power plants, ships, etc.
No cooling liquids
Cast resin transformers need only air for cooling. They are therefore nearly maintenance-free, whereas a liquid-cooled transformer needs much more attention. This also makes cast resin transformers eco-friendlier since no liquid coolants – of whichever chemical composition – can be released into the environment.

Cast resin insulation guarantees secure performance of the transformer with no need for complicated and costly maintenance. Preventive maintenance of cast resin transformers consists in a simple visual check.
Low operating costs
Low losses in the magnetic core and in the windings reduce the costs of operation.
Simplicity of installation
The transformer is a key component in the electrical supply network, therefore ease and quickness of its installation should be born in mind. A cast resin transformer is easily installed, e.g. no blast walls are necessary. Consequently, the planning of the installation is simplified and installation costs are saved.

Instead of traditional transformer bays, simple IP enclosures can be used for access prevention and protection of cast resin transformers. IP enclosures come in different types and colours depending on the client’s needs and preferences.
Possibility of significant increase in performance
Through optimized forced ventilation there is an increase in performance of about 40%.
High short-time overload capability
Current density in the windings of cast resin transformers is considerably lower than in those of oil-immersed transformers. Hence, short-time load peaks, such as with wind power installations, can be easily overcome with no need to plan adequate oversizing.

The high technology employed in the manufacturing process of windings gives the product a high level of reliability.
Versatility and performance
Cast resin transformers can sustain overloads and perturbations taking place in every installation.

The standard product range from POWER. Sp. z o.o. covers distribution cast resin transformers from 50kVA up to 5000kVA, with insulation class up to 36kV, with Eco-design, reduced or standard losses:
All of our transformers are manufactured in compliance with IEC 60076-11 standard and in particular meet the requirements for climatic (C), environmental (E) and fire (F) classes:
- Climatic class C2: Transformers suitable for working, transportation and storage at temperatures down to -25°C.
- Environmental class E2: Transformers suitable for working in environment where they can be subject to frequent condensation, heavy pollution or a combination of the two.
- Fire class F1: Transformers exposed to a fire hazard. They are characterized by restricted inflammability, low emission of toxic substances and opaque fumes.
Each and every transformer undergo a series of routine tests in compliance with IEC60076-11 at our own testing room, which include:
- Measurement of winding resistance
- Measurement of voltage ratio and check of phase displacement
- Measurement of short-circuit impedance and load losses
- Measurement of no-load losses and no-load current
- Insulation test of MV against LV and earth
- Insulation test of LV against MV and earth
- Overvoltage test
- Measurement of partial discharges
On customer’s request, the following type and special tests can be conducted:
- Noise level measurement
- Temperature rise test
- Impulse test
Our design and construction capacity can satisfy all various needs as to different types and applications of transformers:
- Autotransformers
- Transformers for 6-12-18-24-36 pulse converters
- Photovoltaic application
- Wind power transformers
- Earthing transformers
- Reactors
- HV-HV transformers and LV-LV transformers
- Application for traction and for testing rooms
- 3 PT100 probes for windings temperature
- 4 lifting eyebolts
- 4 bidirectional wheels
- 2 earthing links
- Identification plate
- Tapping terminal board on MV side
- CE marking
- Forced cooling system (POWER Sp. z o.o. production)
- Anti-vibration pads for transformers wheels (POWER Sp. z o.o. production)
- Temperature relay for PT100 and PTC sensors
- Additional PT100 or PTC probes
- Enclosures with different degrees of IP protection
- Earthing bolts with spherical end Ø 20mm, Ø 25mm and Ø 30mm
- 2 or more contact thermometers
- Marshalling boxes with one or more relays wired according to client’s specifications
- Electrostatic screen between primary and secondary windings
- Bi-metal (Al/Cu) plates
- Surge arrester in MV side from 3 kV up to 36 kV
- MV and LV terminals brought to the side of the transformers
- MV or LV terminals in the bottom
- MV and LV windings in copper
- LV in cast encapsulate coils
- Transformers with over temperature in class B
- Installation above 1000 m a.s.l.
- Ambient temperature above +40˚C
- Ambient temperature below -25˚C