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Power Transformers

Since developing Korea's first 154 kV extra-high-voltage transformer in 1969, Hyosung Heavy Industries has been at the forefront of extra-high-voltage transformer technology, developing Korea's first 345 kV and 765 kV transformers in 1978 and 1992, respectively.

Hyosung Heavy Industries, which manufactures a variety of transformers with a maximum voltage of 765 kV and a maximum capacity of 1,500 MVA, offers both inner and outer-type products, allowing customers to choose from a vast selection.

As a world-class transformer brand that provides solutions for customers in over 70 countries by designing, manufacturing, and testing in accordance with each country's standards, we have manufactured more than 7,500 extra-high-voltage transformers at the Changwon Plant alone. Since the 1970s, when we began exporting transformers, our quality and service have been recognized by customers worldwide. Furthermore, our global production network, which includes local production bases in the US and China, is contributing to the development of global power grids.

We manufacture transformers for special applications, such as eco-friendly ester oil transformers, gas-insulated transformers, mobile transformers, phase-shifting transformers, and STATCOM transformers. We also provide products for diverse industries including railroads, electric furnaces, and data centers.

Features and Benefits

We offer specialized solutions based on superior technology.

  • Extra-high-voltage Technology

    • First to develop 765kV transformer in Korea and Asia; supplied 765kV transformers to global markets including North America, Central America, and India.
  • Robust Technology

    • With the one of the largest engineering organization in the world and 50 years of accumulated technology, our 765kV transformer has the superior thermal, dielectric strength, and mechanical strength under seismic, short-circuit, and various transportation conditions.
  • Sophisticated Technology

    • Designed to meet the varied needs of customers in over 70 countries worldwide.
    • Delicate custom design optimized for even extreme operation conditions including deserts, seismic regions, and highly-corrosive atmosphere.
  • Green Technology

    • We offer eco-friendly, customer-optimized solutions based on low-loss technology.
    • We are the leader in low-noise technology and eco-friendly transformers.
  • Smooth Project Execution

    • We have professional transportation and installation capabilities around the world.
    • We offer engineering consultation prior to the placement of an order, ensuring close communication and prompt delivery.
  • Smart Technology

    • A comprehensive condition monitoring for transformer is available via online measurement of parameters such as UHF PD, temperature for hotspot and each spot, and DGA.


Discover solutions customized for multiple industries.

  • Transmission and distribution substations

  • Power plants

  • Railroads

  • Water treatment facilities

  • Petrochemical plants

  • Mining and steel industry

  • Data centers

  • General industry

Special Transformers

Discover special transformers suitable for your field of application.

  • 01 Eco-friendly

    Ester oil transformers

    • It is eco-friendly as it is insulated with biodegradable natural ester oil or synthetic ester oil.
    • Due to the high flash point and fire point of transformer oil, the risk of fire is minimal (Fire Safety Class K, above 300℃).
    • It is possible to reduce the firewalls, oil collection facilities, and firefighting facilities, thereby decreasing substation construction costs and insurance premiums.
    • Through an explosion-proof design, it is safe for use in the city center and underground substations of buildings.
  • 02

    Gas-insulated transformers

    • Insulated with SF6 gas for excellent thermal and chemical stability (stable up to 500°C).
    • Since SF6 gas is non-explosive, there is no danger of fire or explosion.
    • Excellent cooling capability by water- cooled heat exchanger.
    • It ensures easy maintenance.
  • 03

    Mobile transformers

    • Our design and manufacturing services are customized to customer specifications.
    • We ensure rapid manufacturing and supply.
    • Assembly on site is not required.
    • It is exceptionally reliable.
  • 04

    Phase shifting transformers

    • It is connected in series with the transmission line to control the power flow of the transmission line by regulating the phase angle between the source and load terminals.
    • It can be used to connect power systems between countries or improving an unbalanced power flow in parallel transmission lines by varying the phase angle.
    • It helps ensure the economic feasibility, stability, and reliability of power systems.
  • 05

    STATCOM transformers

    • Utilizing large capacity inverter technology, power systems are controlled with high-speed precision.
    • It is designed and manufactured to be minimally impacted by harmonic current and DC current generated by large capacity inverters.
    • There are numerous advantages, including enhanced grid stability, increased transmission capacity, enhanced power quality, and reduced transmission costs.
  • 06

    Scott transformers

    • It is primarily used to power electric railways.
    • It resolves three-phase imbalance caused by single-phase load of the electric railway.
    • To obtain a single phase from three phases, a Scott connection is formed by two single phases, the primary and T.
    • Standard specifications include 30/40MVA, 45/60MVA, 60/80MVA, and 90/120MVA, etc.
  • 07

    Furnace transformers

    • It is designed with strong dielectric characteristics and high short circuit strength.
    • High reliability is ensured against frequent switching surges and short circuits that occur due to the operating characteristics.
    • Due to very large current at the low voltage side, a Bar-coil that can withstand high currents is used.


Our track records speak for ourselves.

  • Republic of Korea

    765kV 667MVA Transformer

    • Korea Electric Power Corporation (KEPCO), substation
    • Since 1969, when we developed Korea's first 154kV extra-high voltage transformer, we have been KEPCO's main supplier of extra-high voltage transformers
  • United States

    765kV 750MVA Transformer

    • USA, substation
    • We have been the primary supplier of extra-high-voltage transformers in the North America market since the 1990s
  • Indonesia

    500kV 1,370MVA GSU Transformer

    • Indo Raya Tenaga, thermal power plant
    • Indonesia JAWA 9 & 10 CFPP Project
    • Delivered large-capacity GSU transformers for use in thermal power plants
  • Saudi Arabia

    380kV 502MVA Transformer

    • SEC, substation
    • A leader in the TR, reactor and GIS markets in Saudi Arabia for over 2 decades
  • United Kingdom

    400kV 240MVA Eco-friendly ester oil Transformer

    • National Grid, substation
    • Delivered 400kV eco-friendly ester oil transformers
  • Australia

    330kV 200MVA Phase Shifting Transformer (PST)

    • Transgrid, substation
    • Australia Project Energy Connect (largest power transmission project in the southern hemisphere)
    • Delivered Korea's first 330kV PST


We adhere to global standards and maintain an environment of the highest quality.

View all certifications
  • IEC

  • ANSI

  • IEEE

  • NEMA

  • BS

  • JIS

  • JEC

  • ISO9001

  • ISO14001

  • ISO45001

  • EN ISO3834


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