HV/MV Equipment
Gas-insulated Current Transformer up to 550 kV

Grid Solutions > HV/MV Equipment > Instrument Transformers > STEF

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Gas-Insulated Magnetic Voltage Transformers (VT)

The STEF voltage transformer with composite insulator for 123 kV up to 550 kV voltage. The STEF is top core design (primary coil on the head) up to 170 kV and dead tank design (coil at the bottom) for upper voltages. The STEF is compliant with IEC and IEEE or equivalent standards.

Key Features

  • Production in dust-free room
  • Line discharge capability
  • Long term accuracy stability and long life insulation
  • Decades of on-site experience
  • g3 capability - green gas for grid with very low global warming potential


  • Rated voltage: up to 550 kV
  • Thermal burden: up to 5,000 VA
  • Higher secondary output available
  • Voltage factor 1.5/30s or 1.9/8h
  • Up to 3 secondary windings