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WindSTAR transformers

Hitachi Energy's WindSTAR liquid-filled transformers are ideal solutions for fixed and floating offshore wind applications. Their reliable, energy-efficient, and compact construction is well suited for installation in wind turbine towers or nacelles.

As turbine size increases offshore (8 MW and above), turbine transformers must remain compact and lightweight with a minimal footprint while also meeting specific application needs, mechanical structural constraints, and costs.

Based on the 36 kV class established solution for large offshore turbines, Hitachi Energy has developed a transformer that is able to step up the voltage at a world record of 66 kV and meet the most stringent electrical and mechanical requirements. With its WindSTAR transformer, Hitachi Energy is bringing a step change in the scale of power and voltage.

Product scope

  • Available for 36 and 72.5 kV class
  • Available for power rating superior to 7 MVA
  • Available for 50 Hz and 60 Hz
  • Available for IEC and ANSI markets


  • Vibration and short-circuit proof 
  • Modular design for any customer request
  • Made for durability in salt mist environments
  • Environmentally friendly and fire-safe ester insulation liquid
  • High-temperature insulation material

Why Hitachi Energy?

  • World’s leading manufacturer of 66 kV wind turbine transformers for the world’s most powerful offshore wind turbines
  • Best-in-class solution to withstand sudden variable loading and typical extreme environmental events of offshore conditions
  • Hitachi Energy turbine transformers are specially designed to meet the specific application needs
  • Hitachi Energy proven TrafoStar Design used for offshore wind turbines reaching 10 MW and above
  • Estimated installed base of more than 1,000 units worldwide
  • A key actor in international technical standard publication and at the forefront of developing new requirements for transformers
  • Specialized service team for offshore interventions

Get to know more

WindSTAR™ for the next generation of offshore wind turbines

Part of categoryPress Release
10-09-2020 | 4 min read

Hitachi Energy wins significant purchase agreement for offshore wind transformers

Part of categoryPress Release
16-02-2020 | 4 min read

WindSTAR™ transformers for MHI Vestas’ offshore wind farm in the UK

power plant engineer for substation

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