Hyosung develops 22.9kV solid state transformer for AI data center power

Hyosung Heavy Industries has developed a 22.9 kV solid state transformer (SST) designed to connect directly to urban distribution networks, as the company pushes further into US power infrastructure tied to AI and data center growth. The unit is a 1.05 MVA-class SST, developed in 2022, and Hyosung is pairing that technology with an expanding US manufacturing footprint for high-voltage grid equipment.

The 22.9 kV, 1.05 MVA-class SST uses power semiconductors to control voltage and current while maintaining insulation functions associated with conventional transformers. Hyosung describes it as intended for next-generation power conversion applications, with a target use case of direct interconnection to distribution systems at 22.9 kV.

For data center operators, the practical point is that medium-voltage distribution and conversion gear is becoming a real limiter as sites scale: higher power demand stresses not just utility interconnect capacity, but also the equipment supply chain for transformers and switchgear. SSTs promise finer-grained control than traditional iron-core transformers, but they also introduce a different risk profile around power electronics, thermal design, and serviceability. In other words, it’s not just a nameplate question.

On the manufacturing side, Hyosung has invested a total of USD 300 million to acquire and expand an ultra-high-voltage transformer manufacturing facility in Memphis, Tennessee. The company says that once the ongoing expansion is complete, the facility will be among the largest ultra-high-voltage transformer production operations in the US.

Hyosung has also formed a joint venture with Quanta Services to locally produce 72.5 kV to 800 kV ultra-high-voltage circuit breakers in Pennsylvania. The company says this makes it the first Korean power equipment manufacturer with local US production capabilities for both ultra-high-voltage transformers and circuit breakers. Quanta cites its US customer network supporting infrastructure work for large power-demand facilities.

Chairman Hyun-Joon Cho said, “Driven by the expansion of AI and data centers, power infrastructure has now become a core industry directly linked to national security.”

Hyosung also referenced additional grid technologies it’s working with for the US market, including energy storage systems (ESS), STATCOM, and HVDC.