Power Transformers

Transformadores de potencia Imefy


IMEFY transformers are manufactured according to IEC 60076. IMEFY also manufactures transformers according to different standards (ANSI, BSI, IEEE, NEMA, etc...). All IMEFY power transformers are manufactured with the following characteristics:


  • Substation transformers.
  • Generation transformers.
  • Transformers for rectifiers and furnace.
  • Traction transformers.
  • Autotransformers and reactances.


  • Power ratings: From 2.5 MVA up to 160 MVA
  • Insulation level: From 12 KV up to 245 KV
  • Frequency: 50 or 60 Hz
  • Voltage regulation in any of its windings:
    • By means of off load tap changer: up to 17 positions.
    • By means of on load tap changer: up to 35 positions.
  • Vector group: monophasic or triphasic transformers with possibility of triangle or delta connections in any of its windings.
  • Number of windings: Possibility to manufacture transformers with primary + secondary, double secondary, compensation or load tertiary and any other type according to requirements of customer.
  • Cooling: transformers are manufactured with the following type of cooling according to UNE-EN/IEC 60076:
    • ONAN
    • ONAF
    • KNAN
    • KNAF


  • Core: two, three or five columns, cut and assembled with any of the qualities of magnetic steel available in the market.
  • Windings: They can be helical windings, layer windings, interleaved, continuous disc, interleaved disc, and mixed windings with any type of conductors, aluminum or copper.
  • Drying treatment, both of each single windings by means of oven, as drying of active part by means of atmosphere impregnation of kerosene by Vapour Phase System.
  • Iron works: design and mechanical simulation by software of finite element mesh. Manufacture by qualified welders and tightness test by penetrating liquids. The standard exterior coating C3-M quality, with possibility of suitable treatment to withstand high pollution, humidity and ambient salinity up to C5-M.
  • Terminals: They can be supplied open type, both polymeric or porcelain, RIP technology (resin impregnated paper) or plug-in type.
  • Main protections:
    • Buchholz Relay
    • Jansen Relay for tap changer.
    • Thermometer
    • Thermal Image Relay
    • Thermostat
    • Direct measure device of temperature by optical fiber.
    • Oil level
    • Overpressure valve
    • Continuous monitoring system of water content and dissolved gasses in oil.
    • Dehydrating breather

    • More information of this type of transformers is available in the brochures which can be downloaded in the website.