HD Hyundai Electric has developed Korea's first 420-kilovolt (kV) SF6-free high-voltage circuit breaker, strengthening its push into Europe's growing market for environmentally friendly power equipment.

The company said Monday that it had completed development of the 420kV-class circuit breaker, becoming the first Korean company to do so and the third company globally.

The eco-friendly circuit breaker replaces sulfur hexafluoride (SF6), a potent greenhouse gas widely used in high-voltage equipment, with a C4-based gas mixture. The change requires the insulation and interruption systems to be redesigned to accommodate the properties of the alternative gas.

The 420kV-class product is designed for ultra-high-voltage transmission networks and must demonstrate stable, long-term performance under extreme operating conditions, making its development particularly challenging, the company said.

HD Hyundai Electric has independently developed SF6-free circuit breakers since 2021, beginning with a 170kV-class product and later adding 145kV- and 72.5kV-class products. The latest development expands its portfolio across key voltage levels.

The 400kV transmission networks where 420kV-class circuit breakers are used account for more than half of the transmission networks operated by major European transmission system operators, making the product a key requirement for entering Europe's ultra-high-voltage power infrastructure market.

The European SF6-free high-voltage circuit breaker market is expected to grow as tighter European Union regulations on fluorinated greenhouse gases coincide with increased investment in power grids. The market is projected to reach around 3 trillion won ($2.2 billion) by 2030.

HD Hyundai Electric said it has secured eligibility to supply European transmission operators by passing pre-qualification reviews during the product development stage.

"We are currently pursuing a long-term supply agreement with a major British power company and aim to secure our first order by the end of this year or early next year," an HD Hyundai Electric official said.

"Within the next three years, we plan to complete additional SF6-free circuit breakers in the 300kV and 362kV classes."