KEPCO Accelerates 500 kV East Coast–Seoul HVDC Converter Stations to Power Semiconductor Mega-Clusters

Korea Electric Power Corporation (KEPCO) and joint-venture partners have advanced construction milestones for the 500 kV East Coast–East Seoul HVDC transmiss...

KEPCO Accelerates 500 kV East Coast–Seoul HVDC Converter Stations to Power Semiconductor Mega-Clusters

Korea Electric Power Corporation (KEPCO) and joint-venture partners have advanced construction milestones for the 500 kV East Coast–East Seoul HVDC transmission corridor, deploying heavy-duty converter transformers and 90°C high-temperature underground HVDC cables to deliver 8 GW of base-load clean power to the Yongin semiconductor cluster.

Powering the World’s Largest Semiconductor Manufacturing Hub

The greater Seoul metropolitan area accounts for over 40% of South Korea’s national electricity demand and hosts world-leading semiconductor manufacturing fabs in Yongin and Pyeongtaek. To overcome severe transmission bottlenecks preventing coastal nuclear and renewable generation from reaching inland fabs, KEPCO is executing the multi-trillion won East Coast–Seoul 500 kV HVDC link.

The project comprises Phase 1 (Donghae to Sin Gapyeong) and Phase 2 (Donghae to East Seoul), utilizing a combination of overhead mountainous transmission corridors and 85.5 km sections of 500 kV high-temperature underground XLPE cable systems.

High-Capacity 500 kV Converter Transformers and Valve Hall Integration

At the terminal converter stations, KEPCO and technology partners KAPES (a joint venture with GE Vernova) and LS Electric are installing single-phase 500 kV converter transformers designed to withstand the rigorous harmonics and DC bias voltages characteristic of high-power Line Commutated Converter (LCC) and Voltage Source Converter (VSC) topologies.

The converter transformers feature specialized oil-barrier insulation systems and ester/mineral hybrid dielectric shielding to minimize partial discharge and prevent localized core saturation during rapid power ramping between 2 GW blocks.

Strategic Transition to Domestic HVDC Standardization

Beyond securing critical power for chip manufacturing, the project marks a watershed in South Korea’s indigenous power engineering capability. Domestic manufacturers—including LS Cable & System, Taihan Cable, and Iljin Electric—are producing the 500 kV cables and neutral lines, while domestic transformer facilities localize high-voltage bushings and tap-changers.

Commercial operation of the primary HVDC stages is scheduled between late 2026 and 2028, laying the foundation for the planned 620 km West Coast Underwater HVDC Highway.