Korea Electric Power, Hyosung Heavy Industries push to localize HVDC technology

Domestically developed components to be applied to Saemangeum–West Hwaseong HVDC line; Hyosung Heavy Industries selected to lead Phase 1 valve and controller localization

Hyosung Heavy Industries CEO Woo Tae-hee delivers a congratulatory address at a completion ceremony held at Korea Electric Power Corporation's Yangju substation in 2024 to mark the installation of a 200 MW voltage-source HVDC system. [Hyosung Heavy Industries]

Korea Electric Power Corporation has teamed up with Hyosung Heavy Industries to localize key components for large-capacity voltage-source high-voltage direct current transmission systems and carry out demonstration projects. The initiative aims to reduce dependence on foreign equipment and accelerate grid construction as demand grows for renewable energy integration and long-distance power transmission.

Hyosung Heavy Industries has been credited with building energy self-reliance for South Korea over the past 27 years, beginning with the country's first static synchronous compensator installation in 1999.

Korea Electric Power Corporation is pushing ahead with the localization and demonstration of key components for large-capacity voltage-source HVDC systems to ensure timely construction of the national power grid and stable electricity supply, according to the power industry.

HVDC technology converts electricity generated at power plants into direct current for long-distance transmission. It reduces energy losses over long distances and is used to deliver power from offshore wind farms and large-scale renewable energy sources to demand centers such as the Greater Seoul area. Voltage-source HVDC is considered particularly well-suited to managing the volatility of renewable energy, as it allows rapid adjustment of power flow.

Major components for large-capacity voltage-source HVDC systems are currently supplied by a handful of global companies, including Hitachi, Siemens and GE. Korea Electric Power Corporation has determined that securing independent technology for these key components is essential to building out the grid on schedule and strengthening the competitiveness of the domestic power equipment industry.

The government and Korea Electric Power Corporation are pursuing the localization of three core HVDC components: valves, controllers and conversion transformers. Valves and controllers are the central devices in conversion equipment that transforms alternating current into direct current and back again, while conversion transformers regulate voltage throughout the process.

For the valve and controller segment, applications were solicited from interested companies in July, and Hyosung Heavy Industries was selected following an expert evaluation on Aug. 31. Development of conversion transformers has been under way since September last year, with Hyosung Heavy Industries, LS Electric, HD Hyundai Electric and Iljin Electric all participating.

Hyosung Heavy Industries was chosen in the latest selection process based on a comprehensive assessment of its technology acquisition plan, localization strategy and project execution plan. The company was particularly recognized for advancing from MW-class technology to GW-class technology development starting in 2025.

Workers assemble a transformer at Hyosung Heavy Industries' factory in Changwon. [Hyosung Heavy Industries]

Hyosung Heavy Industries has been developing voltage-source HVDC technology since a 20 MW demonstration project on Jeju Island in 2012. The company independently developed key 200 MW-class components — including converter valves, a control system and conversion transformers — and installed them at the Yangju substation last year. It now plans to advance that work toward 2 GW-class large-capacity HVDC technology through the current project.

The company is also executing 52 STATCOM projects worldwide. A static synchronous compensator maintains stable grid voltage to improve the reliability of power systems and is considered a prerequisite for expanding renewable energy, which can introduce instability into the grid.

Hyosung Heavy Industries is regarded as one of the few domestic companies with in-house design and manufacturing capabilities for voltage-source HVDC conversion valves and controllers.

After successfully demonstrating a 200 MW voltage-source HVDC system in 2024, the company secured the first commercial track record of its kind in South Korea. It has also been credited with verifying the stability of converter valve switching operations, hardware control algorithms and response characteristics through integration with Korea Electric Power Corporation's grid.

Hyosung Heavy Industries is also participating in the government's West Coast Energy Highway Phase 1 project, working to build a 2 GW-class large-capacity bipole system based on its proven proprietary technology. The company is developing key equipment and control technology with a target completion date of next year. It was selected as the lead company for valve controllers in the West Coast Energy Highway Phase 1 project following an evaluation by a panel of power and localization experts.

Korea Electric Power Corporation plans to apply domestically developed key components to the Saemangeum–West Hwaseong HVDC project to verify their performance and reliability in an actual power grid. The corporation intends to leverage that demonstration track record to enter overseas markets, positioning HVDC as a new export driver for the power industry.

oskymoon@heraldcorp.com