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Inductive Voltage Transformer Type UT 550 kV

Outdoor inductive voltage transformer with oil-filled stainless steel bellows and paint-free housings

UT inductive voltage transformers are of single-phase design and intended for connection between phase and ground in networks with insulated or direct-grounded neutral points.  

The extremely low core flux density enables the UT to withstand continuous 110 percent rated voltage continuously, and provide 190% overvoltage rating for 8 hours.  Hermetic sealing of the design is accomplished using stainless steel bellows above the oil to prevent free-breathing outside moisture-laden air.

The distributed gap core design offers low losses and ensures the unit has a relative high accuracy burden rating of 400 VA (ZZ).


  • Revenue metering
  • Control
  • Indication
  • Relay protection

Why Hitachi Energy?

The UT is a very capable inductive voltage transformer for withstanding extremem conditions with an excellent service record.  The standard design has a porcelain insulator with silicone rubber insulators available as an option, providing even better performance in heavily polluted environments.  Hitachi Energy offers our users unique advantages as follows:

  • Excellent application engineering support ensures optimal solutions for your project
  • Designed for environmentally diverse conditions - polar to desert
  • Low loss distributed gap core ensures the best accuracy performance with the lowest core losses for the duration of service life
  • Three secondary tapped windings

Brief performance data

Installation Outdoor
Design Inductive type
Insulation Oil-paper
Highest voltage for equipment 145 - 525 kV
Voltage factor (Vf) Up to 1.9-8hrs 
Insulators Porcelain (standard)
Silicon rubber (by request)
Creepage distance ≥ 25 mm/kV (longer by request)
Service condition  
  •  Ambient temperature
-40ºC to +40ºC (standard)
  •  Design altitude
Maximum 1000 m (standard)
  *Other temperatures and altitudes are possible
Accuracy Meets all IEC and IEEE metering and protection classes

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