In the transformer industry, a “newcomer” is rising. For over a century, transformers have been known as heavy, iron-and-copper “iron lumps”: iron cores, copper windings, and electromagnetic induction — these textbook concepts have been their classic identity.
Now, AI computing power has pushed electricity demand to a new level. As a result, a concept that had lain dormant for more than half a century — the solid-state transformer (SST) — is being thrust back into the spotlight. NVIDIA has sent a clear signal: 800-volt high-voltage DC paired with solid-state transformers will become the “power supply architecture” for next-generation computing factories.
In Zhejiang, a province that is a major hub for transformers and power electronics, strategic planning for the solid-state transformer industry has entered a meaningful implementation phase. The Zhejiang Provincial Department of Economy and Information Technology is currently seeking public input on measures to promote solid-state transformer industry development. Industry consensus judges that after 2028, solid-state transformers will see large-scale application.
Fundamental Differences Between Solid-State and Traditional Transformers
Traditional transformers basically do one thing: electromagnetic transformation. High-voltage electricity enters through fine windings, creates a magnetic field in the iron core, and low-voltage electricity is induced in thicker windings. How does the voltage change? It depends on the turns ratio of the two windings. Meanwhile, to maintain 50-hertz alternating current, the iron core must be large and heavy.
The operational logic of a solid-state transformer is entirely different: it first converts incoming industrial-frequency AC to DC, then inverts the DC to high-frequency AC — raising the frequency from 50 Hz to tens or even hundreds of thousands of Hertz — then uses a small “high-frequency transformer” for isolation and voltage transformation, and finally, depending on requirements, rectifies to DC output or inverts back to industrial-frequency AC output.
When frequency goes up, things change. For the same power level, the cross-sectional area of the magnetic core and the number of windings are inversely proportional. At 50 Hz, the iron core needs to be as thick as a bowl; at 20,000 Hz, it only needs to be as small as a fingernail. This is why solid-state transformers can shrink to one-third to one-fifth the size of traditional products.
Why Now?
In 1968, General Electric engineer McMurray first proposed the concept of a solid-state transformer. Over the following decades, it never disappeared — it just lived a very “niche” existence. Places like railway traction stations and ships, where weight and volume are extremely sensitive and users are willing to pay for performance, were its earliest adoption sites. In other words, it was not unseen; it simply lacked the reason to become indispensable.
The reason is straightforward. The power system is the most safety- and stability-conscious system in the world. For a device to “rise,” it cannot rely solely on being “advanced.” It needs demand, components, standards, cost, and verification to all come together.
And today, these conditions are gradually maturing. AI computing centers require 800-volt high-voltage DC, hybrid AC/DC integration, and millisecond-level response to fluctuating loads. Heavy-truck ultra-charging demands megawatt-level power, bidirectional interaction, and integrated solar-storage-charging coordination. Large-scale grid integration of photovoltaics, wind power, and hydrogen energy requires the power conversion stage to shift from “passive, rigid, and slow” to “active, flexible, and fast.” These demands that traditional transformers cannot meet are exactly what solid-state transformers are suited for.
Policy, Standards, and Demonstration Projects
The “Implementation Plan for Promoting Digital-Green Collaborative Transformation (2026-2030),” jointly issued by the Cyberspace Administration of China, the National Development and Reform Commission, the Ministry of Industry and Information Technology, and five other departments, explicitly explored 800-volt high-voltage DC power supply architectures for computing facilities for the first time. The T/CEATEC 249-2026 “Solid-State Transformers Part 1: Grid-Connected Solid-State Transformers for Photovoltaics” was released and implemented this August, specifying magnetic core material selection, multi-layer winding layout, heat dissipation optimization, and shielding grounding methods.
Demonstration projects are beginning to materialize. Zhangqiu, Shandong, commissioned the nation’s first electric-grid-friendly electric heavy-truck demonstration station using solid-state transformers, with a maximum single-charging-station power of 800 kilowatts. Changzhou, Jiangsu, deployed China’s first batch of 1,500-kilovolt-ampere solid-state transformers, reducing heavy-truck charging time by approximately 30 percent compared to traditional 360-kilowatt charging piles.
In Zhejiang, scenario-based applications are unfolding progressively. In the Ningbo Cixi hydrogen-electric coupling DC microgrid demonstration project, solid-state transformers effectively solved hydrogen energy grid integration and fluctuation issues. In the Shaoxing Shangyu AC-DC hybrid microgrid demonstration project, SST applications significantly reduced intermediate conversion stages, improving functional integration, controllability, and protection capabilities.
Costs Are Easing
Silicon carbide (SiC) devices account for 30 to 40 percent of total solid-state transformer costs — the single largest cost item. In the past, SiC solutions carried a price premium of three to four times that of traditional approaches. However, according to industry authoritative institutions, domestic technology achieved a key breakthrough in 2025, raising SiC device self-sufficiency from 10 percent to 28 percent, which directly drove solid-state transformer costs down by 40 percent compared to 2023 levels.
Consider computing centers. The traditional logic for computing center power supply is “transformer plus UPS plus multi-stage distribution” — from 10-kilovolt medium-voltage AC to the DC power servers need, electricity goes through three to four conversion stages, with comprehensive efficiency losses reaching 7 to 10 percent. The solid-state transformer straightens this path: 10-kilovolt high-voltage electricity is converted in a single step to 800-volt DC usable by servers, achieving power supply efficiency above 98.5 percent and reducing floor space by more than half. For a 10-megawatt computing center, this can save over 2 million kilowatt-hours of electricity annually.
“Rising” Does Not Mean “Replacing”
Amid the enthusiasm, it is essential to distinguish between two things: the “rising” of solid-state transformers means becoming irreplaceable in specific scenarios, not a comprehensive replacement of traditional transformers.
“Solid-state transformers will not fully replace traditional transformers,” said Zhan Jiangyang, a third-level expert in substation technology at State Grid Zhejiang Electric Power Company, who has deepened his research in the transformer field. For solid-state transformers to truly “rise,” several hurdles remain. Safety and reliability must withstand the test of time; overall lifespan and long-term operational stability lack practical engineering verification; and the assessment standards for type tests and full-scale tests are not yet established.
High-voltage and large-capacity areas remain weaknesses. Current technology is mainly limited to distribution networks at 35 kilovolts and below. High-voltage, large-capacity technology remains in the exploratory stage and cannot replace traditional transformers in main grids in the short term. This is partly constrained by the intermediate high-frequency transformer used for electrical isolation — while higher frequencies reduce size, the insulation, loss, and heat dissipation requirements for transformers increase sharply, and for a considerable period this will remain the core bottleneck limiting voltage escalation and capacity expansion.
In high-voltage, large-capacity main grid scenarios, traditional transformers remain the main act. The true opportunities for solid-state transformers lie in specific scenarios: medium-and-low voltage DC distribution networks, AI data centers, and megawatt-level ultra-charging stations. These scenarios demand higher levels of DC power supply, flexible power scheduling, and power quality. DC-direct-output solid-state transformers, with higher efficiency and smaller footprint, will claim their home field here.
[Image 1: Panoramic view of the hydrogen-electric coupling demonstration project. The image shows outdoor power facilities, energy storage equipment, transmission towers, and hydrogen-related installations. | Photo by Yao Ke-bin] [Image 2: Internal components of a solid-state transformer. Behind the transparent panel, multiple layers of power electronic modules, copper busbar connections, and control wiring are visible. | Photo by Yan Luyao] [Image 3: Three-port solid-state converter cabinet. Inside an indoor equipment room, the white cabinet door is open, revealing neatly arranged power modules and liquid cooling pipes. | Photo by Peng Jiaying]
Submitted by: Zhu Feibai (Media Integration Center), Jiang Hang (Electric Power Research Institute), Zhai Shengwen (Quzhou Company)