High-voltage direct current (HVDC)

Hitachi Ltd., Siemens AG, General Electric Vernova and ABB Group are among the companies active in HVDC. Hitachi Ltd. appears in patent-holder data and works on DC circuit-breaker protection; Siemens AG works on offshore VSC link controls. General Electric Vernova has recent patent activity and a VSC-HVDC joint venture with LS Electric. These firms span equipment, controls and project delivery.

Scibreak AB and 3 5 Power Electronics GmbH are the startups identified in the available HVDC data. Scibreak develops fast DC circuit breakers and studies their effects on cable stresses in multi-terminal systems. 3 5 Power Electronics focuses on interoperability in multi-vendor grids, including voltage disturbances during line-fault recovery. The supplied information describes their work, but does not establish a comparative investment or performance ranking.

North China Electric Power University, Xi'an Jiaotong University and China Electric Power Research Institute are among the leading research organizations in the available activity data, with 267, 270 and 229 documents, respectively. Their work includes converter protection and control, device stress, offshore VSC-HVDC design and fault-tolerant modular multilevel converter topologies. Tsinghua University is also active in converter control and voltage balancing.

The funding data lists $238,459,046 across 60 grants since 2020. It also records 21 financing rounds totaling $33,105,555,734. That round total includes broad corporate and infrastructure financings, so it should not be treated as a clean measure of capital invested specifically in HVDC technology. The grant figure is the more directly relevant reported funding indicator.

Hitachi Ltd. leads the listed patent holders with 36 patents. General Electric Vernova follows with 14, while Xiamen Hongfa Electrical Power Controls Co. has 12. Patent activity stands at 275 patents in the defined 24-month window, with growth of -35.3%. These figures show a recent decline in patent activity, even as current research and project announcements continue.

Recent developments include Tsinghua University, State Grid Corporation of China and Huairou Laboratory's hybrid commutated converter result in August 2026, and the LS Electric–GE Vernova VSC-HVDC joint venture announced in September 2026. Research also targets lightweight offshore converters, grid-forming controls, cable insulation and fault detection. Together, these efforts address both the performance of converter technology and the practical needs of renewable-energy transmission.

The main approaches include line-commutated converters, two-level voltage-source converters and modular multilevel converters, alongside cable, overhead-line and multi-terminal grid systems. LCC is suited to bulk transmission but is vulnerable to commutation failure. VSC offers flexible control, while MMC adds modularity at the cost of more complex control and protection. Cables and overhead lines serve different route and installation conditions.

China leads the country data with 16,396 documents, followed by the United States with 6,708. Germany, India and the United Kingdom follow with 3,142, 3,124 and 2,979 documents, respectively. These figures indicate that research and industry activity is geographically broad, though China accounts for the largest share in the available country breakdown.

HVDC is used for renewable-energy evacuation, offshore wind connections, long-distance bulk transmission, cross-border interconnectors, urban grid reinforcement and island links. Renewable-energy evacuation is the largest listed application, with 2,426 documents; offshore wind connections account for 1,429. The technology is especially relevant where power must travel over long distances, cross water, or connect grids that do not operate in synchronism.