Korea's three power equipment companies (Hyosung Heavy Industries, HD Hyundai Electric, and LS Electric) are racing to develop direct current (DC) transmission and distribution technology. Power generated from renewable energy, which the government is driving, is direct current, and DC is more advantageous than alternating current (AC) for long-distance transmission to artificial intelligence (AI) data centers amid a construction boom.
Hyosung Heavy Industries is independently developing technology related to DC transmission. HD Hyundai Electric and LS Electric have moved to develop technology through cooperation with overseas operators.
According to the power industry on the 7th, Korea Electric Power Corporation (KEPCO) held the "K-DC Industry Expansion 2026" event on the 2nd at the LS Electric Cheonan business site. Based on demonstration results for high-voltage direct current transmission (HVDC) technology and medium-voltage direct current transmission (MVDC) and low-voltage direct current transmission (LVDC), KEPCO plans to expand the scope of DC technology to distribution networks and industrial sites.
◇ HD Hyundai Electric and LS Electric build DC distribution in their own buildings
Until now, the standard in the transmission and distribution market has been built around alternating current. AC became the mainstream because it makes voltage transformation and long-distance transmission easier. But with advances in technology, DC has also become easier to transform at high voltage. In addition, because renewable energy produces DC, there is now a possibility that transmission and distribution will be reorganized around DC.
DC transmission and distribution refers to building transmission lines that send electricity generated at power plants over long distances and distribution lines that allocate and supply power in buildings or homes using the DC method.
Many electronic devices use DC power, including personal computers (PCs) commonly used in homes, LED lighting, and battery-powered mobile phones. But most national power grids, including those in Korea and the United States, are based on AC. That is why PCs have adapters that convert AC power to DC.
This process has the problem of causing power loss. If a converter that changes AC to DC is installed at a building entrance, each electronic device does not need to go through a power conversion process, reducing power conversion losses.
HD Hyundai Electric and LS Electric have succeeded in building DC distribution facilities in their own buildings. In 2023, HD Hyundai Electric installed a 1 MW-class DC distribution facility for buildings at the HD Hyundai Group global research and development (R&D) center (GRC) in Seongnam, Gyeonggi Province.
This facility was jointly developed with KEPCO. The 1 MW-class DC distribution facility supplies power to GRC's LED lighting, heating and cooling systems, EV fast-charging stations, and R&D facilities. A HD Hyundai Electric official said, "It is meaningful that we commercialized technology that had remained at the demonstration stage."
DC distribution facilities were also applied to the "DC Factory," for which LS Electric held a completion ceremony on the 2nd at its Cheonan business site. LS Electric built DC-dedicated core equipment at the DC Factory, including a solid-state transformer (SST) and a solid-state circuit breaker (SSCB). Based on power delivered through DC distribution, the company plans to mass-produce power conditioning systems (PCS) for energy storage systems (ESS).
◇ Power equipment companies are developing voltage-source HVDC transformers as a national project
Power equipment companies are developing "voltage-source high-voltage direct current (HVDC) transformers" needed for DC transmission, going beyond DC distribution. They are key components of the "West Coast energy highway," which the government is pushing to send renewable energy produced in the Honam and Chungcheong West Coast regions to the Seoul metropolitan area, where power demand is concentrated.
A voltage-source HVDC transformer converts AC and DC and enables real-time bidirectional power control. The current-source HVDC transformer developed in the past could only deliver renewable energy generated in Jeju to the mainland. A voltage-source HVDC transformer not only sends renewable energy from Jeju to the mainland but also makes it possible to send power from the mainland to Jeju when the Jeju region lacks electricity.
Each company's development strategy differs. Hyosung Heavy Industries is pursuing independent development. Hyosung Heavy Industries independently developed 200 MW-class voltage-source HVDC transformer technology. This equipment was installed at the Yangju substation in Gyeonggi Province in 2024. However, the capacity required for the West Coast energy highway is 2 GW-class, leaving the challenge of increasing performance tenfold.
HD Hyundai Electric and LS Electric have each partnered with Hitachi Energy of Sweden and GE Vernova of the United States, leaders in voltage-source HVDC transformers. Hitachi Energy has supplied more than 70% of the voltage-source HVDC transformers installed worldwide. In Dec. 2024, it completed the Wando–East Jeju system, the nation's first voltage-source HVDC project.
An official at a power equipment company said, "The national project to develop voltage-source HVDC transformers ends in late 2027," and added, "The goal is to achieve localization, build it on the West Coast energy highway, and accumulate references to break into a market where Hitachi Energy, GE Vernova, and Siemens Energy hold more than 90%."