The CIGRE B5 → IEC TC 57 Pipeline Becomes Formal: What the New Category A Liaison Means for IEC 61850

CIGRE Study Committee B5 ("Protection and Automation") and IEC Technical Committee 57 ("Power systems management and associated information exchange") have always been adjacent. SC B5 publishes Technical Brochures on PAC architectures, process bus implementation, virtualisation, and engineering practice. TC 57 publishes the normative standards that those architectures depend on — most visibly IEC 61850 (WG 10), IEC 61850 for DERs (WG 17), IEC 61850 for hydropower (WG 18), and IEC 62351 (WG 15) for cybersecurity. Authors and experts overlap between the two bodies. Convenors and secretaries move between them. Reading any recent CIGRE TB and any recent IEC 61850 part, it is obvious that the same set of utilities and vendors is talking to itself in two different rooms.

SC B5's Secretary, Peter Bishop (Transpower NZ), reports in the PAC World Issue 075 SC B5 update that a formal channel has now been established:

"IEC Technical Committee 57 […] have established a 'category A' liaison with CIGRE SC B5. With increasing deployment of IEC 61850 based PACS (Protection, Automation and Control Systems) including fully digital systems using process bus and the associated engineering and maintenance a liaison with IEC TC 57 is considered invaluable for the work of B5. This also formalizes already existing links and collaborations." [1]

The "formalizes already existing links and collaborations" clause is the operative one. Until now, CIGRE TB output reached IEC 61850 through informal author overlap and through individual experts who happened to sit on both sides. With a Category A liaison in place, that route is procedural: documented, defined in the ISO/IEC Directives, and visible in the IEC comment trail.

What Category A actually means

IEC distinguishes three liaison categories, defined in the ISO/IEC Directives Part 1. They are not labels of warmth; they are operational permissions.

Category A liaisons "make an effective contribution to the work of the technical committee or subcommittee". The IEC explicitly states that Category A liaison organizations are "given access to all relevant IEC documentation and are invited to IEC meetings", and — most importantly for working group output — that working groups under TC/SC level "comprise experts individually appointed by P-members, A-liaisons of the parent committee and C-liaison organizations". [2]

Category B is reserved for organisations that want to influence the work but only at the policy level (typically intergovernmental bodies).

Category C is read-only: the C-liaison "indicated a wish to be kept informed" and gets "access to reports", but "C-liaisons are not able to propose new work items. C-liaison experts may only attend committee plenary meetings as observers if expressly invited by the committee to attend." [2]

In other words, the new liaison gives SC B5 three concrete things it did not have as an institution before:

1. Standing access to TC 57 documents — drafts, comments, minutes — for every working group inside TC 57, not just the ones whose members happened to share lunch with a B5 author at the last Paris session.
2. Standing invitations to TC 57 meetings — at the TC level and at the WG level, so the same engineer can carry context from a B5 working group into a TC 57 working group draft without losing fidelity.
3. The right to nominate experts to TC 57 working groups — alongside experts nominated by IEC P-member national committees and C-liaisons. This is the channel that turns "CIGRE recommends" into "IEC 61850 specifies".

For engineers who have watched a CIGRE TB lose its sharpest recommendations between the brochure draft and the IEC publication that should reflect them, the third item is the one to pay attention to.

What flows through the pipeline

The set of CIGRE B5 working groups currently producing material directly relevant to IEC 61850 is wider than a single name suggests. The pipeline already has work in it; the liaison gives that work a defined exit ramp.

flowchart LR
    subgraph B5["CIGRE SC B5 · Protection and Automation"]
        direction LR
        subgraph PUB["Brochures published"]
            direction TB
            WGA["WG B5.69 · TB 949<br/>Process bus implementation (2024)"]
            WGB["WG B5.82 · TB 977<br/>Education / CPD<br/>update of TB 599"]
            WGA --- WGB
        end
        subgraph ACT["Working groups still active"]
            direction TB
            WGC["WG B5.84 · vIED framework<br/>TB due Q1 2028"]
            WGD["WG B5.86 · PACS asset mgmt<br/>TB due Q1 2029"]
            WGE["WG B5.87 · Digital transformation<br/>of PAC · expanding IEC 61850"]
            WGF["WG B5.88 · Implementation guide<br/>for fully digital PACS"]
            WGG["WG B5.90 · new (2026)<br/>Commissioning of fully digital PACS"]
            WGH["WG B5.91 · new (2026)<br/>Monitoring and diagnostic of PACS"]
            WGC --- WGD --- WGE --- WGF --- WGG --- WGH
        end
    end

    LIA{{"Category A liaison<br/>access · meetings · experts"}}

    subgraph TC57["IEC TC 57 · Power systems management"]
        direction TB
        WG10["WG 10 · IEC 61850"]
        WG17["WG 17 · IEC 61850 for DER"]
        WG18["WG 18 · IEC 61850 for hydropower"]
        WG15["WG 15 · IEC 62351 cybersecurity"]
        WG10 --- WG17 --- WG18 --- WG15
    end

    B5 --> LIA --> TC57

    linkStyle 0,1,2,3,4,5,6,7,8 stroke-width:0px

What this changes for engineers

For an engineer reading IEC 61850 drafts or CIGRE brochures, day-to-day nothing changes — and no immediate improvements should be expected. Both the IEC standards roadmap and the CIGRE brochure roadmap are running on their own schedules. What changes is the institutional relationship between them. CIGRE is the largest international association of large electric systems, and its working groups absorb feedback from utilities, manufacturers, and integrators worldwide — feedback that has always been relevant to IEC 61850 but has reached IEC only through individual experts and informal channels. The Category A liaison gives that feedback loop institutional form: the body best placed to gather end-user experience now has a documented route into the body that writes the binding standards.

A concrete illustration of what the loop could close sits in the current publication schedule. The IEC TC 57 work programme (snapshot 20 May 2026) [3] schedules IEC PAS 61850-90-32 — "Use of virtualized environment in IEC 61850 power utility automation system" — for publication in December 2027. CIGRE WG B5.84, the working group writing the framework for virtualised IEDs, has its Technical Brochure due in early 2028. The framework brochure that ought to feed the IEC PAS arrives a quarter or more after the PAS it should have informed.

A CIGRE Technical Brochure can play one of two roles relative to an IEC publication: input to a draft that is still being written, or feedback on a text already published. When the brochure and the IEC document land in the same quarter, it does neither well — too late to be cited as input, too close in time to read as feedback on something the field has had any chance to use.

What the Category A channel closes is exactly this kind of gap. Drafts cross the boundary while both documents are still being written, and comments are lodged formally rather than passed in working-group corridors. Whether the channel gets used vigorously or perfunctorily will show up in the documents themselves over the next two amendment cycles — what changes today is that the channel now exists.

Sources

[1] Bishop, P. "CIGRE Study Committee B5". PAC World, Issue 075, 29 April 2026. https://www.pacw.org/cigre-study-committee-b5-25

[2] IEC. "About TC/SC liaisons — Category A". https://www.iec.ch/standardsdev/how/partners/cat_a.htm . Definitions follow ISO/IEC Directives Part 1, Edition 17.0, available at https://storage-iecwebsite-prd-iec-ch.s3.eu-west-1.amazonaws.com/2021-07/isoiecdir1%7Bed17.0%7Den.pdf

[3] IEC TC 57 (Power systems management and associated information exchange). Work Programme and Up-to-Date Project Plan, snapshot 20 May 2026. The forecast publication date for IEC PAS 61850-90-32 (December 2027) is taken from this snapshot. The status document for TC 57 work is referenced as IEC document 57/2851/INF (IEC-member access).