How IEC 61850 Editions Succeed Each Other — As Seen in the UCA IUG Registry

The UCA IUG registry is a primary source. It does not issue press releases or announce milestones — it simply records what has been tested, by whom, and when.

To understand the numbers, you need to know how edition transitions work — and what formal decisions governed them. The registry data does not exist in a vacuum: it is the direct output of a structured process driven by IEC standard versions and UCA IUG testing policy decisions. This article traces that process, using the registry as evidence.

How Edition Transitions Work: The UCA IUG Policy Framework

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Ed.2 UCA testing start (~2012) is approximate. Ed.2.1 IEC publication ~2020. UCA IUG policy sources: Herbert Falk announcements, April 2021 and November 2020. Ed.2 UCA conditional phase (post-2024) guaranteed until at least 2028.

The succession of IEC 61850 editions follows a defined process. Herbert Falk, Vice-President of Testing at UCA IUG, issued the formal policy announcements that govern the transitions visible in the registry.

Edition 1 was published by IEC in 2004–2005 and formally withdrawn in December 2012, when Edition 2 superseded it. UCA IUG continued Edition 1 testing after the withdrawal. The end-of-life was phased: new Edition 1 testing was prohibited after April 30, 2021, and certificates could only be posted for tests started before that date, with a final deadline of November 1, 2021. The registry's last Edition 1 entries (1 certificate in 2022) reflect tests initiated just before the cutoff.

Edition 2 was published by IEC in 2011. Under the April 2021 UCA IUG policy, standalone Edition 2 testing — without the requirement to also pass Edition 2.1 — remained permitted until January 2024. After that date, Edition 2 testing is still available, but only to vendors who first pass Edition 2.1 conformance. This conditional path is guaranteed to remain open until at least 2028. The 113 Edition 2 certificates issued in 2023 — the highest single-year total for any edition in the registry — directly reflect this deadline: vendors completed Ed.2-only certification before the January 2024 cutoff, producing the sharpest peak in the dataset.

Edition 2.1 (formally: Amendment 1 to Edition 2) was published by IEC around 2020. UCA IUG conformance testing for Edition 2.1 became available no later than January 2022 per the April 2021 policy, and became mandatory from January 2024. A 10-year minimum guarantee period applies: Edition 2.1 testing is formally assured for at least 10 years after any future Edition 3 publication. The current mandatory phase has no scheduled end date.

The Core Finding: 2025 Was the Tipping Point

The registry spans three active editions: Edition 1 (805 certificates), Edition 2 (730 certificates), and Edition 2.1 (115 certificates). Looking at the annual certification pace from 2016 onward shows a clear three-phase transition.

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Edition 1 certifications effectively ceased after 2022 — the last two years with any Ed.1 entries show only 26 (2021) and 1 (2022). Edition 2 dominated from 2016 through 2024. Edition 2.1 first appeared in the registry in 2021 (4 certificates), grew to 14 in 2023, and then accelerated sharply.

In 2023, Ed.2.1 represented 11% of new certifications. In 2024, that share grew to 28%. In 2025, it crossed 71% — meaning that in the last full calendar year, three out of every four new conformance certificates were for Edition 2.1.

The first months of 2026 confirm the same picture: 83% of new certifications are Ed.2.1.

Data: full UCA IUG registry, exported March 18, 2026. Ed.2.1 share calculated against Ed.2 + Ed.2.1 for years where Ed.1 = 0.

The chart makes the policy threshold visible: from January 2024, when standalone Ed.2 testing without Ed.2.1 ceased to be available, Ed.2.1 certifications have consistently exceeded Ed.2. The acceleration is not a gradual market uptake curve — it is the direct output of the mandatory requirement that had been publicly announced three years prior.

By Test Type: Sampled Values Already All-Ed.2.1

The full registry covers six certification categories across all three editions. Adding Edition 1 to the picture reveals the historical depth behind each category.

Server dominates: 1,302 certificates across all editions, representing 79% of the entire registry. The Merging Unit category has 28 Edition 1 entries — reflecting that MU certification was actively pursued during the Ed.1 era and has since slowed. SCL tools have no Ed.1 certification history in the registry at all.

The Sampled Values result stands out: every SV certification in the registry is Ed.2.1. None are Ed.2 or Ed.1. The SV conformance test procedure for Ed.2.1 was developed and deployed at a point when Ed.2.1 was already the available standard path — vendors entering SV certification found Ed.2.1 as the only route.

Who Leads in Ed.2.1

Among vendors with the most Ed.2.1 certifications in the registry:

CYG SUNRI, the Chinese protection relay manufacturer, leads in Ed.2.1 certifications and has no Ed.2 or Ed.1 entries — they entered the certification programme at the point when Ed.2.1 was already the standard path. GE Vernova shows the same pattern. Siemens and NR Electric carry all three editions, indicating active portfolio renewal over time.

Looking at total certified products across all editions, DNV Netherlands' top client is Schneider Electric Industries SAS (4 Ed.1 + 46 Ed.2 + 4 Ed.2.1 = 54), while Schweitzer Engineering Laboratories leads in absolute volume with 73 total certificates across Ed.1 (44) and Ed.2 (29).

Client vs Server: Role Breakdown

Server and Client are the two largest certification categories, together accounting for 1,568 of 1,650 records (95% of the registry). Their adoption dynamics differ.

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The full picture across all editions reveals the depth of the transition. Server role has dominated in absolute volume throughout — from 84 Ed.1 + Ed.2 certificates in 2016 to 42 Server certificates in 2025 (39 of which are Ed.2.1). The Client role peaked at Ed.2 in 2021 (21 certifications) and is now predominantly Ed.2.1 in new certifications.

Server Ed.2.1 adoption outpaced Client in both absolute numbers and timing. In 2023, there were 12 new Server Ed.2.1 certifications but zero Client Ed.2.1. Client Ed.2.1 activity only began meaningfully in 2024 (3 certificates) and accelerated in 2025 (14 certificates).

Looking at 2025 only: Server is 74% Ed.2.1 (39 of 53), Client is 64% Ed.2.1 (14 of 22). The pattern suggests that protection and control device manufacturers (predominantly Server role) led the transition, with SCADA and gateway vendors (predominantly Client role) following approximately one year later.

Sampled Values Publisher: A 100% Ed.2.1 Category

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Ten Sampled Values certificates exist in the registry. All ten are Edition 2.1. There are no Ed.1 or Ed.2 SV certifications.

The certifications are distributed across three years: 2021 (2), 2023 (3), 2024 (5). No SV certifications were recorded in 2022 or 2025. Given the small total count, year-to-year variation reflects the limited number of vendors pursuing this specific test path rather than any trend reversal.

SV certification tests the device's ability to publish and/or subscribe to sampled values over the process bus — a role typically performed by merging units and intelligent electronic devices with direct analog input. The complete absence of Ed.1 and Ed.2 entries likely reflects the timing of the SV conformance test procedure: by the time it was widely available through accredited labs, Edition 2.1 had become the active test procedure version.

All SV-Certified Products: Complete List

Because the SV category is small, the full registry is worth naming explicitly. Below are all ten Sampled Values certifications as of March 2026, showing each product's publish/subscribe capability:

SV Role derived from IEC 61850 Blocks Certified: Publisher = Sampled Value Publish (11a), Subscriber = Sampled Value Subscribe (11b). DOBLE DRTS 66L is relay test equipment certified for basic exchange with SV capability.

SV Publishers (11a): 6 products — Siemens SIPROTEC 5 6MU85, Siemens SIPROTEC 5 7SL87, Hitachi Energy SAM600, Siemens 7VU85, I.S.A. Altanova DRTS 66L, NR Electric PCS-221S Merging Unit.

SV Subscribers only (11b): 3 products — Efacec BCU 500, NR Electric PCS-902S, Siemens 7SL87.

Three vendors account for all ten: Siemens (4), NR Electric (2), Hitachi Energy (1), Efacec (1), I.S.A. Altanova (1), DOBLE Engineering (1). The SIPROTEC 5 6MU85 and 7SL87 were the first two SV-certified products in the registry (2021), establishing the initial certification baseline for the category.

GOOSE Performance: 30 Certificates, Transition Just Beginning

GOOSE Performance testing evaluates timing and reliability of GOOSE message delivery under load — a test category focused on network-level behavior rather than conformance to the data model. The registry shows 30 GOOSE Performance certificates across all editions.

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The GOOSE Performance category was most active in 2016 and 2018, each with 7 certifications. Activity dropped substantially through 2019–2023, averaging 1–2 certificates per year. Edition 2.1 GOOSE Performance certifications only began appearing in 2024, with 1 certificate that year, 2 in 2025, and 1 in the first months of 2026.

At 4 Ed.2.1 certificates against 20 Ed.2 and 6 Ed.1, the GOOSE Performance category is where the Ed.2.1 transition is least advanced — 16.7% Ed.2.1 share versus 70%+ in Server and Client for 2025. This likely reflects both the specialized nature of the test (not all vendors pursue it) and the smaller pool of labs offering the procedure.

Where Testing Happens

The geography of certification is concentrated. DNV Netherlands has handled more certifications than any other facility across all three editions.

DNV Netherlands alone accounts for 807 certificates — nearly half of the entire registry. It has been the most active lab in all three edition periods. Korea Testing Laboratory (KTL) has significant Ed.2.1 activity at 35 certificates and is the second-most active lab for the newer edition.

Three labs — KERI, TUV SUD Germany, and Xuchang KETOP — show zero Ed.2.1 certificates in the registry. Their pipelines for the newer edition, if active, have not yet produced completed certifications in this dataset. The data does not explain why; the gap is observable.

ABB Switzerland Ltd. (B) appears as a lab with 40 Ed.1 and 8 Ed.2 certifications — this is ABB's in-house accredited test facility, which has historically tested its own products.

What This Means for Procurement

The transition from Edition 2 to Edition 2.1 occurred at the test laboratory level on a defined schedule — the UCA IUG policy published in April 2021 set January 2024 as the mandatory milestone. The majority of new certifications in the registry are Ed.2.1 because that is what the policy requires. The question for procurement teams is whether their technical specifications reflect this structural reality.

Specifying "IEC 61850 conformance" without edition reference leaves room for products certified against Edition 2 or even Edition 1 to qualify. The registry distinction between editions is explicit. Procurement language can be equally explicit.

For brownfield projects, Edition 2.1 includes defined interoperability mechanisms with Edition 1 devices — this is one of the practical additions in the amendment. The cross-edition bridge was a deliberate design decision, not an afterthought.

The full picture: 805 Edition 1 certificates represent the foundation of IEC 61850 adoption — products certified and deployed in substations worldwide over more than a decade. Edition 2 built on that base with 730 certificates from 2015 through 2024. Edition 2.1 has now become the dominant new certification path, with 115 certificates — a number that will grow substantially through 2026 and beyond.

The registry data documents a completed policy-driven transition: from January 2024, Edition 2.1 conformance testing is mandatory at UCA IUG-accredited laboratories. The 2025 and 2026 registry numbers are the direct output of that policy. The shift is not a market preference emerging from vendor choice — it is the result of a process that was publicly announced three years before it took effect.

Source: UCA IUG IEC 61850 conformance certification registry, exported March 18, 2026. Full registry: 1,650 records. Ed.1: 805, Ed.2: 730, Ed.2.1: 115. Registry available at ucaiug.org.