Power transformers
Let your facility run at full pace with our efficient power transformers
R&S offers highly efficient and custom-made power transformers
Power rating: up to 160 MVA
Voltage: up to 220 kV
We produce network transformers for distribution grids, GSU transformers for power plants, cogeneration plants and combined heat and power plants, and special transformers used for industrial purposes and in rail transport. The experience we have acquired over 60 years and in over 1,000 installations makes us a reliable partner.
Benefits that speak for themselves
Achieve maximum efficiency
All our materials and components are ordered exclusively from the world’s top manufacturers, so we can ensure we deliver only high-quality products to our customers. This makes for highly reliable power transformers and gives you the guarantee that you’ll achieve a high level of efficiency.
Get a perfect solution
Each power transformer is one-of-a-kind and specifically designed, allowing you to implement a solution that’s perfectly adapted to your requirements with regard to voltage, power, climate, sound pressure and lots of other criteria.
Cut your investment costs
Benefit from our power transformers’ long service lives. Thanks to our high-quality components and our perfected processes, the average useful lifetime until replacement is required is more than 30 years.
Save time and hassle
We offer you a full package. From consulting services and designing and manufacturing, to repairs and diagnostics, we take care of everything so you can concentrate on your core business.
Increase your system’s reliability
Our power transformers withstand ambient temperatures of -40°C to +40°C. This ensures that the power supply is never disrupted and your system is running at full pace 24 hours a day, seven days a week.
Performance our customers can rely on
„Our ambition at ZREW is clear: to build transformers that operate reliably under real grid conditions for decades.“
Volodymyr Zaytsev – Expert Research & Development Engineering
Want to get technical?
Take a look at our brochure or contact a member of our team today.
Innovative and custom-made solutions
We firmly believe that the only way we can offer you the most innovative and high-quality products for your individual project’s respective requirements is to be a pioneer with respect to new technologies. Our power transformers’ special design and our over 60 years of experience allow us to offer you a fully customisable solution.
GSU power transformer
– Raises voltage in power and cogeneration plants
– Cooperates mainly with production sources
Network power transformer
– Used to reduce voltage in distribution networks
– Most common in distribution companies and large industrial enterprises
Special power transformer
– Used in steelworks to power electrical furnaces
– Used in industrial plants to cooperate with converter systems
– Used in rail traction systems to power rectifier systems
Frequently asked questions
Power transformers
What is a power transformer?
A power transformer transmits large amounts of electrical power at high voltages, for example between a power plant and the transmission grid or within substations – unlike a distribution transformer, which delivers energy to the end consumer in the final step.
Which R&S Group brand manufactures power transformers?
Within the R&S Group, power transformers are manufactured by ZREW in Łódź, Poland.
Up to what rating and voltage does ZREW manufacture power transformers?
ZREW manufactures power transformers up to 160 MVA / 220 kV.
Which applications does ZREW supply power transformers for?
ZREW supplies power transformers for power plants, combined heat and power plants, wind farms and distribution networks, as well as special transformers for industrial applications such as converter and furnace transformers.
Which standards are ZREW power transformers manufactured and tested to?
ZREW power transformers are designed, manufactured and finally tested to PN-EN, IEC, IEEE and GOST.
Can ZREW power transformers be supplied with an on-load tap changer?
Yes. ZREW equips its power transformers with tap changers from renowned manufacturers that allow voltage regulation under load or in the de-energised state, operated electrically on site or remotely.
How does a power transformer differ in design from a distribution transformer?
Power transformers such as those from ZREW typically have two-chamber oil conservators, on-load tap changers and cooling systems (e.g. oil-air coolers) and are designed for much higher voltage levels than distribution transformers.
Can ZREW power transformers be designed for extreme climatic conditions?
Yes. In addition to the standard version for −25 °C to +40 °C, ZREW also manufactures versions with accessories for operation at ambient temperatures from −40 °C to +40 °C.
Does ZREW also repair and modernise old power transformers?
Yes. ZREW carries out repair, modernisation and service work on oil-immersed transformers with ratings up to 150 MVA and voltages up to 145 kV, regardless of their original year of manufacture. This limit applies to the repair of existing units; new ZREW transformers are manufactured up to 160 MVA / 220 kV.
GSU power transformer
What is a GSU power transformer?
A GSU transformer (generator step-up transformer) connects a generator – for example in a power plant or wind farm – to the transmission grid, stepping the generator voltage up to the higher grid voltage.
Which R&S Group brand supplies GSU power transformers?
GSU power transformers are part of ZREW's power transformer portfolio, which includes step-up designs for power plants and wind farms, among others.
Which generating plants are GSU transformers used for?
GSU transformers are used wherever generating plants – such as power plants, combined heat and power plants or wind farms – need to be connected to the higher-level transmission or distribution grid.
Up to what rating are ZREW GSU transformers available?
GSU transformers fall under ZREW's general power transformer portfolio with an upper limit of 160 MVA / 220 kV.
What distinguishes a GSU transformer from a network transformer?
A GSU transformer typically steps up the voltage of a generating plant for feeding into the grid, whereas a network transformer links different voltage levels within the transmission or distribution grid, often as a step-down design.
Can GSU transformers be equipped with condition monitoring?
Yes. On request, ZREW installs a modern monitoring system that can also be used for continuous condition monitoring of GSU power transformers.
Which tests do GSU transformers undergo before delivery?
GSU transformers undergo the same extensive final acceptance tests as other ZREW power transformers, including measurement of the turns ratio, winding resistances and no-load and load losses as well as impulse voltage tests to IEC, PN-EN or GOST.
Network power transformer
What is a network power transformer?
A network transformer links different voltage levels within the transmission or distribution grid, for example in substations between extra-high, high and medium voltage.
Which R&S Group brand supplies network transformers?
Network transformers are part of ZREW's power transformer portfolio and are offered explicitly for distribution networks, among others.
Up to what voltage level are ZREW network transformers available?
Network transformers fall under ZREW's general power transformer portfolio with an upper limit of 220 kV or 160 MVA.
Are network transformers supplied as step-up or step-down designs?
ZREW offers both step-up and step-down designs, depending on whether the voltage in the grid needs to be increased or reduced.
Are ZREW network transformers also suitable for substations in the distribution grid?
Yes. ZREW explicitly names distribution networks as one of the main applications of its power transformers, which includes classic substation applications.
Can network transformers be equipped with an on-load tap changer for automatic voltage regulation?
Yes. On request, ZREW equips its power transformers with on-load tap changers that allow automatic voltage regulation during grid operation.
Which cooling systems are available for network transformers?
Galvanised, detachable radiators are used as standard; on request, ZREW also equips its network transformers with modern oil-air coolers (ONAF).
How are existing network transformers monitored in operation?
ZREW offers extensive on-site diagnostics for network transformers, including dissolved gas analysis (DGA), SFRA/FRA winding tests and thermography – without having to take the transformer out of service.
Special power transformer
What is a special power transformer?
A special power transformer is a power transformer with a non-standard electrical or mechanical design for particular industrial applications, for example as a converter or furnace transformer.
What is a converter transformer?
A converter transformer supplies converter or rectifier systems with the appropriate voltage and is specifically designed for the transient interference voltages and harmonics caused by power converters.
What is a furnace transformer?
A furnace transformer supplies industrial furnaces (e.g. arc or induction furnaces) with high currents under frequently changing load requirements and is designed for correspondingly high mechanical and thermal stress.
Which R&S Group brand offers special power transformers?
Special power transformers such as converter and furnace transformers are part of ZREW's portfolio and are manufactured for industrial applications up to the general limits of the power transformer range.
Why do special power transformers need reinforced insulation?
In applications with frequent transient interference voltages, such as those caused by converters or furnaces, the paper insulation ages faster. Special power transformers therefore have reinforced layer insulation and an earthed shield between the windings.
Are special power transformers custom-designed or supplied from stock?
Special power transformers are always designed for the specific project and application, as their electrical and mechanical properties are tailored to the respective industrial use.
Can special power transformers also be designed for renewable energies?
Yes. ZREW supplies power transformers for wind farms and other renewable energy applications, among others, and special designs can also be used depending on the connection concept.
Which tests are common for special power transformers?
In addition to the standard final acceptance tests to IEC, PN-EN or GOST, special power transformers often undergo additional tests depending on the application, such as vibroacoustic analyses or verification of short-circuit strength.