LS Electric and Hyosung Heavy Industries, representing Korea's power equipment industry, squared off at ELEX Korea 2026 by both declaring, side by side, that they would complete localization of voltage-source HVDC (high-voltage direct current) technology by next year. Competition has begun in earnest to win orders and secure the lead in the West Coast Energy Expressway, a large-scale national project worth 11 trillion won.
◇ LS Electric fronts transformers, Hyosung Heavy fronts valves
At ELEX Korea 2026, the country's largest power and energy exhibition that opened on the 4th at COEX in Gangnam District, Seoul, LS Electric highlighted its in-house technology by placing at the front of its booth a model of a 500-megawatt (MW) HVDC converter transformer slated for delivery within the year to the Incheon Shin-Bupyeong substation. An HVDC converter transformer is a key facility that precisely adjusts voltage during the conversion where AC and DC intersect, boosting transmission efficiency and grid stability.
Hyosung Heavy Industries also showcased a model of the currently operating 200 MW-class HVDC Yangju converter station and a real STATCOM valve (a device that keeps voltage constant) incorporating its own device technology.
The HVDC converter transformer and STATCOM valve each company highlighted are the two core devices that make up an ultra-high-voltage HVDC system. If the valve converts AC and DC and serves as the brain controlling the system's overall flow, the transformer plays the role of the grid's heart, adjusting voltage levels to match the network. By putting forward devices they have each commercialized, they are underscoring that they are the right fit for the West Coast Energy Expressway project.
◇ An uncharted path… Emphasis on zero-defect stability
The West Coast Energy Expressway project, on which they are staking everything, is a national grid initiative to supply power generated from nuclear plants, offshore wind, and solar along the west coast to major demand centers such as semiconductor clusters in the Seoul metropolitan area and AI data centers. To boost local acceptance, it adopts an HVDC method using subsea cables to increase transmission efficiency.
In particular, the project's core, voltage-source HVDC, unlike the conventional current-source method, can send power bidirectionally in real time and has emerged as a next-generation grid technology to stably supply renewable energy with highly variable output.
The challenge is that the project's transmission scale is 8 gigawatts (GW), a large capacity equivalent to running eight large nuclear power plants at once. It is an uncharted path that corporations in Korea have not yet taken, and a single accident could paralyze the entire national industry, making stability the top priority.
Accordingly, at the exhibition that day, LS Electric and Hyosung Heavy Industries both emphasized "zero-defect stability." LS Electric highlighted its on-the-ground experience as the only Korean company to supply key equipment to the 3 GW "Bukdangjin–Godeok" project and the 4 GW "East Coast–Seoul metropolitan area" HVDC project, racking up more than 1 trillion won in orders.
Building on this, the strategy is to secure validated design capabilities through cooperation with GE Vernova, one of the global top three HVDC corporations, and produce the equipment directly at the Busan HVDC-dedicated plant.
Kang Min-chan, Head of Team for Grid Solution Sales at LS Electric, said, "We have already secured a significant portion of HVDC technology and are at the stage of needing to advance the system-level engineering," adding, "We intend to work with GE because we judge that combining the know-how LS Electric has built up over more than 20 years in HVDC grids with leading global technology is the most stable path to localization."
◇ Hyosung touts "purely domestically developed" approach… Next year is the watershed
Hyosung Heavy Industries is aiming to seize the initiative with a "purely domestically developed" solution through self-developed technology that handles every step from system design to manufacturing in-house. The company also highlighted that it is operating, without disruption, Korea's first voltage-source 200 MW-class HVDC Gyeonggi Yangju substation. However, there is a significant technical gap between MW-class and GW-class HVDC in terms such as control complexity, making further technology development essential to secure large-capacity operating capability.
Kim Gyeong-ho, manager on the DC Systems Business Team of the Power PU at Hyosung Heavy Industries, said, "We are accelerating efforts to scale up voltage-source HVDC facilities and enhance operational stability, based on control technology validated through the commercial operation of the Yangju substation," adding, "Recently, global big tech companies have been visiting the Yangju substation one after another to inspect the facilities and explore large-scale power supply options for AI data centers."
A power industry official said, "The key to an 8 GW-class project is the engineering capability to operate ultra-large facilities stably," adding, "Domestic corporations are rushing from the design stage for a scale they have never attempted before, so next year the competition for leadership to prove full-fledged practical capability will intensify further."