Combined Instrument Transformers – Type VAU

Končar has developed combined transformers in 1994, and has since acquired extensive manufacturing and service experience with over 5.000 units installed worldwide. The unique and original single insulation design makes these units stand out in comparison to conventional solutions present on the market today.

The combined transformers are designed with exceptional longevity and reliability, aiming for at least 50 years of service life.


  • Um: 72,5 to 550 kV
  • In: up to 6000 A
  • Short circuit: up to 100 kA (Idyn: 250 kA peak)
  • Secondary cores: up to 10
  • Secondary windings: up to 6

Key Features

  • Top core design (low primary winding losses)
  • Low leakage reactance type
  • Unique ferroresonance immune design (open type voltage transformer magnetic core)
  • Explosion-safe - Internal arc resistant 
  • Partial discharge free on power-frequency withstand voltage
  • Stainless steel bellows oil expansion system
  • Extreme temperature range available (-60 to +60 °C)
  • Extensive experience in seismically active regions
  • Minimum oil design
  • Maintenance free
  • Space and cost savings