Published by MVSST Power · November 2026
Three solid-state transformer deployments were reported within eleven days in October 2026: Delta's prefabricated, containerised SST-based DC power system, launched at Energy Taiwan 2026 in Taipei on 14 October; Guangdong Power Grid's 1 MW ±10 kV medium-voltage DC SST, commissioned at Hengqin in Zhuhai and reported on 19 October; and TBEA's Roy Sync series at 2.5 MW, declared in mass production on 24 October in Tianjin.
Different markets, different voltage classes, different applications — so it is tempting to file these as a general "commercialisation year" story. That framing misses the useful part. Read together, the three show the product splitting into two species with opposite architectural roles, and they show that the efficiency figure every vendor leads with has stopped being a differentiator. All three report 98.5%, and all three mean something different by it.
The Hengqin unit and the TBEA unit belong to the same component family and are not the same product. Guangdong Power Grid's device is a bipolar ±10 kV medium-voltage DC SST rated 1 MW, developed in-house by the Zhuhai Power Supply Bureau as the core demonstration output of a Southern Power Grid key science and technology programme [2].
Its job is architectural: establish a DC "common bus" so that rooftop PV, storage, EV chargers and data centres connect locally and share one dispatch system, and — via a multi-port flexible interconnection device — lash independent feeders into a mesh so power can route around a faulted line. The voltage class is the specification here; DC bus topology is the value.
TBEA's Roy Sync is the mirror image. Rated 2.5 MW, it takes 10 kV AC in and delivers 800 V DC out, deliberately removing the line-frequency transformer and the separate multi-stage rectification stage in between [3]. Here the 800 V DC output is the specification, because that is the interface the AI load side is standardising on, and the value is holding that bus stable against a load that swings in milliseconds. Its first field application is not a data centre at all but heavy-truck ultra-fast charging, at the Zhiyun Green Logistics station in Guangyuan, Sichuan [3].
The Hengqin team's account of how they cut size and cost is worth close reading, because it names the lever most SST discussion skips: raising the voltage each power module can withstand halved the module count, and footprint and cost both fell by more than 30% on that basis [2].
In a cascaded MV SST the module count drives the bill of materials, the enclosure volume, and the number of gate drivers, sensors and bypass paths that must all be qualified. Raising switching frequency shrinks the transformer but adds loss and EMI; raising per-module blocking voltage deletes whole modules and everything attached to them. That is why device voltage class, not frequency, tends to set achievable power density.
TBEA quotes gains on the same axis: roughly 45% less copper and about 60% less floor area than a conventional scheme, plus an internal estimate that a 1 MW rack saves about 280 000 kWh per year [3]. Those last three figures are the company's own internal calculations rather than third-party measurements, and should be weighted accordingly.
Delta states SST conversion efficiency of up to 98.5%, and separately claims a 4–5% gain in grid-to-chip energy efficiency in AI data centres [1]. TBEA states maximum whole-machine efficiency of 98.5%, beside input THDi below 3% and output regulation within 1% [3]. Guangdong Power Grid states maximum whole-machine efficiency of 98.5%, beside operating noise below 65 dB [2].
Three vendors, three markets, one identical headline. When a number converges this tightly across competitors it stops carrying information — especially because the boundaries differ. Delta's 98.5% is the SST alone, with the 4–5% figure applied to the wider chain. TBEA's is a whole-machine number published beside power-quality limits. Guangdong's is a whole-machine number published beside an acoustic limit. None of the three defines its measurement boundary precisely enough for cross-vendor comparison, and none should be read as one.
What the three announcements actually compete on is everything around the converter. The Hengqin SST suppresses fault current within 0.1 ms [2] — a grid-support function a line-frequency transformer does not perform at all, and one that matters the moment DC is on the bus, because a DC fault gives no zero crossing to wait for.
Roy Sync uses N+1 redundancy in which a failed power module is bypassed automatically within milliseconds with supply uninterrupted, and provides millisecond-level load response for compute load swings [3]. Delta's contribution is delivery-side: the SST, DC/DC converters, control equipment and DC protection are integrated in the factory into a containerised unit, cutting on-site deployment time by up to 50%, with an optional high C-rate battery for millisecond-level power support [1].
None of these are converter-topology claims. Bypass behaviour, fault ride-through, load buffering and factory pre-integration are system claims, and they are now the part of an SST that is hard to copy.
The three projects sit at visibly different stages. TBEA has completed type testing with reports from Dongdian Testing Technology (Xi'an) and TÜV Rheinland, runs batch production at a Tianjin base with capacity stated at 200 units a year, and offers indoor and outdoor variants [3]. Delta's contribution is a prefabrication and integration model rather than a capacity figure; Guangdong Power Grid's is a single demonstration unit, with grid-wide scale-up stated as intent rather than as an order book [2].
Only one of the three has published an annual capacity figure, and only one has published third-party type-test reports. That gap — not the efficiency number — is what currently separates a product from a project.
| Project | Rating and interface | Declared performance | Stage |
|---|---|---|---|
| Guangdong Power Grid, Hengqin [2] | 1 MW, ±10 kV DC bus | 98.5% max whole-machine; noise <65 dB; fault-current response <0.1 ms; module count halved, footprint and cost −30%+ | Single demonstration, commissioned |
| TBEA Roy Sync [3] | 2.5 MW rated, 1–5 MW scalable; 10 kV AC → 800 V DC | 98.5% max whole-machine; THDi <3%; regulation <1%; N+1 with ms bypass | Type-tested, mass production, 200 units/yr |
| Delta prefabricated SST system [1] | Containerised SST + DC/DC + control | SST efficiency up to 98.5%; grid-to-chip +4–5%; deployment time −50% | Launched and exhibited |
Related: MV SST in H2 2026: Pilots, Products and the Move to Procurement · 2026: SST Commercialization Hits Its Inflection Point · Medium-Voltage SST Topologies, Control and the Engineering Gap
Disclaimer: This article is compiled from the publicly available sources listed above for industry information purposes only. Performance figures are as published by each project's own organisation, are measured on different system boundaries, and are not independently verified or directly comparable. Figures described by the manufacturer as internal estimates are identified as such. Design decisions on a specific project require project-specific engineering analysis.
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