In 2026, an important event took place in the evolution of the IEC 61850 standard: a new structure of the IEC 61850-7-xxx model documents was put up for vote.
It is not about replacing IEC 61850 with some new standard, but about restructuring the part that used to be concentrated mainly in IEC 61850-7-4: logical nodes, data objects and their distribution across thematic documents.
An important clarification: Common Data Classes / CDCs are not "moving" into these new documents. They remain the subject of IEC 61850-7-3, which defines the common data classes and related structures used when building IEC 61850 models. The new 7-xxx documents are about logical node classes and the corresponding data objects, and about how they are split across the application-oriented parts of the standard.
Which documents were sent to CDV
On 13 February 2026, seven IEC 61850-7-xxx documents were published for CDV comments. The public commenting was open until 10 April 2026.
This package included:
IEC 61850-7-4 ED3
Communication networks and systems for power utility automation -
Part 7-4: Basic communication structure -
Compatible logical node classes and data object classes -
Core
IEC 61850-7-40 ED1
Communication networks and systems for power utility automation -
Part 7-40: Basic communication structure -
Compatible logical node classes and data object classes -
Common part
IEC 61850-7-43 ED1
Communication networks and systems for power utility automation -
Part 7-43: Basic communication structure -
Compatible logical node classes and data object classes -
Primary equipment
IEC 61850-7-44 ED1
Communication networks and systems for power utility automation -
Part 7-44: Basic communication structure -
Compatible logical node classes and data object classes -
Instrument transformers
IEC 61850-7-400 ED1
Communication networks and systems for power utility automation -
Part 7-400: Basic communication structure -
Compatible logical node classes and data object classes -
Substation automation
IEC 61850-7-401 ED1
Communication networks and systems for power utility automation -
Part 7-401: Basic communication structure -
Compatible logical node classes and data object classes -
Protection
IEC 61850-7-440 ED1
Communication networks and systems for power utility automation -
Part 7-440: Basic communication structure -
Compatible logical node classes and data object classes -
Power quality metering
In other words, instead of one large IEC 61850-7-4 document, a more modular structure takes shape: a core, a common part and separate thematic documents for primary equipment, instrument transformers, substation automation, protection and power quality.
The vote has already closed
Public comments on the documents were accepted until 10 April 2026, and the CDV vote by national committees closed on 8 May 2026.
According to the public project cards, the documents are at stage 40.60 — Close of voting / Enquiry results established, meaning the voting is closed and the results have been forwarded to the technical committee for further processing.
This does not mean the standards have already been published as final international standards. At this stage, the voting results and the comments received must be processed by the technical committee. After that, the document moves on to the next stages of preparing the final text.
The correct way to phrase the current status is:
The CDV vote on the new IEC 61850-7-xxx documents closed on 8 May 2026. The documents have passed the voting stage and are now in the phase of processing the results and the comments. They are not yet final published international standards.
What prEN IEC 61850-7-xxx is
In European catalogues these documents may be listed as prEN IEC 61850-7-4:2026, prEN IEC 61850-7-43:2026 and so on.
prEN stands for Draft of a European Standard, i.e. a draft European standard. It is not a separate independent version of IEC 61850, but a European draft stage of the document in the CENELEC system.
In simplified form:
IEC CDV
→ international IEC project at the Committee Draft for Vote stage
prEN IEC
→ European draft of the future EN IEC document
So both designations may appear in industry materials, but it is important to understand their procedural meaning.
What exactly changes
Until now, the key document for describing logical nodes and data objects has been IEC 61850-7-4. It defined the information model of devices and functions, including the logical node classes and the corresponding data objects.
Now the structure is changing. The big model document is split into several thematic parts.
The description of prEN IEC 61850-7-43:2026 states that the structure of IEC 61850-7-4 Edition 2.1 is changed into several parts — 7-4, 7-4n and 7-4nn. This is done so that individual parts can be updated without having to issue a new edition of the core document each time.
In other words, IEC 61850-7-4 stops being a single big "reference" for all such models. Instead, a family of more specialised documents appears.
flowchart LR
subgraph FUNC["Application area / project function"]
F1["🔌 Primary equipment"]
F2["📐 Instrument transformers"]
F3["🏗️ Substation automation"]
F4["⚡ Protection"]
F5["📊 Power quality<br/>and metering"]
F6["🧩 Common model elements"]
end
subgraph DOCS["IEC 61850-7-xxx (CDV 2026)"]
direction TB
CORE["<b>IEC 61850-7-4 ED3</b><br/>Core · rules and framework"]
COMMON["<b>IEC 61850-7-40 ED1</b><br/>Common part"]
D43["IEC 61850-7-43 ED1<br/>Primary equipment"]
D44["IEC 61850-7-44 ED1<br/>Instrument transformers"]
D400["IEC 61850-7-400 ED1<br/>Substation automation"]
D401["IEC 61850-7-401 ED1<br/>Protection"]
D440["IEC 61850-7-440 ED1<br/>Power quality metering"]
end
CDC["📚 <b>Common Data Classes</b><br/>still in IEC 61850-7-3<br/>(SPS, DPS, INS, MV, CMV, ACT, ACD, ...)"]
F1 --> D43
F2 --> D44
F3 --> D400
F4 --> D401
F5 --> D440
F6 --> COMMON
D43 -. uses .-> CDC
D44 -. uses .-> CDC
D400 -. uses .-> CDC
D401 -. uses .-> CDC
D440 -. uses .-> CDC
COMMON -. uses .-> CDC
CORE --- COMMON
CORE --- D43
CORE --- D44
CORE --- D400
CORE --- D401
CORE --- D440
style CORE fill:#E3F2FD,stroke:#42A5F5,color:#0D47A1
style COMMON fill:#E8F5E9,stroke:#67C23A,color:#1B5E3F
style D43 fill:#FBE9E7,stroke:#E64A19,color:#BF360C
style D44 fill:#FBE9E7,stroke:#E64A19,color:#BF360C
style D400 fill:#FBE9E7,stroke:#E64A19,color:#BF360C
style D401 fill:#FBE9E7,stroke:#E64A19,color:#BF360C
style D440 fill:#FBE9E7,stroke:#E64A19,color:#BF360C
style CDC fill:#FFF8E1,stroke:#E6A23C,color:#7A5418
style F1 fill:#F4F6FB,stroke:#9aa6c8,color:#3a4566
style F2 fill:#F4F6FB,stroke:#9aa6c8,color:#3a4566
style F3 fill:#F4F6FB,stroke:#9aa6c8,color:#3a4566
style F4 fill:#F4F6FB,stroke:#9aa6c8,color:#3a4566
style F5 fill:#F4F6FB,stroke:#9aa6c8,color:#3a4566
style F6 fill:#F4F6FB,stroke:#9aa6c8,color:#3a4566
What IEC 61850-7-4 ED3 Core and IEC 61850-7-40 ED1 Common part will contain
In the new structure of IEC 61850 model documents it matters to distinguish two parts: IEC 61850-7-4 ED3 Core and IEC 61850-7-40 ED1 Common part.
At first glance, both names sound similar: "core" and "common part". But their roles differ.
IEC 61850-7-4 ED3 Core
= the core of the new structure of model documents
IEC 61850-7-40 ED1 Common part
= common logical nodes and data objects applicable across different application areas
IEC 61850-7-4 ED3 Core
IEC 61850-7-4 ED3 Core becomes the base part of the new IEC 61850-7-4xx structure.
Whereas earlier IEC 61850-7-4 was perceived as one big model document with logical nodes and data objects, in Edition 3 it takes on the role of Core — the kernel around which the other thematic parts are built.
It is 7-4 Core that sets the common foundation for the family of documents:
IEC 61850-7-4 Core
IEC 61850-7-40 Common part
IEC 61850-7-43 Primary equipment
IEC 61850-7-44 Instrument transformers
IEC 61850-7-400 Substation automation
IEC 61850-7-401 Protection
IEC 61850-7-440 Power quality metering
The main idea of such a structure is to separate the base model foundation from the application areas. This allows the thematic documents to be developed without having to revise the whole IEC 61850-7-4 as one large document each time.
In other words, IEC 61850-7-4 ED3 Core is not yet another thematic catalogue for one application area, but the central part of the new modular IEC 61850-7-4xx architecture.
IEC 61850-7-40 ED1 Common part
IEC 61850-7-40 ED1 Common part is a separate document for common elements that are used across different application parts of IEC 61850.
While documents such as IEC 61850-7-401 Protection or IEC 61850-7-43 Primary equipment relate to specific functional areas, IEC 61850-7-40 Common part collects the common logical node classes that are not tied to a single application area.
Put simply:
IEC 61850-7-401
= models for protection functions
IEC 61850-7-43
= models for primary equipment
IEC 61850-7-44
= models for instrument transformers
IEC 61850-7-40
= common models applicable across different areas
Thus, 7-40 Common part acts as a common model layer used by the various application parts of IEC 61850-7-4xx.
An important note on data classes
The naming of the new documents uses the wording:
Compatible logical node classes and data object classes
It is important here not to confuse data object classes and Common Data Classes.
Common Data Classes remain the subject of IEC 61850-7-3. It is IEC 61850-7-3 that defines classes such as SPS, DPS, INS, MV, CMV, ACT, ACD and others. These Common Data Classes are then used in IEC 61850-7-4 to define compatible dataObject classes.
The documents IEC 61850-7-4 / 7-40 / 7-401 / 7-43 / 7-44 / 7-400 / 7-440 define the composition and semantics of logical nodes and data objects.
Example:
Logical Node: PDIS
Data Object: Op
Common Data Class: ACT
In this example:
PDIS and Op
→ the IEC 61850-7-4xx domain
ACT
→ the IEC 61850-7-3 domain
So the correct wording is:
The new IEC 61850-7-xxx documents are about logical nodes, data objects and their distribution across thematic model parts. The Common Data Classes remain in IEC 61850-7-3.
This is not the whole IEC 61850-7-x series
An important note: these seven documents are not the whole IEC 61850-7-x series.
The basic structure of series 7 remains broader:
IEC 61850-7-1 — basic principles and models;
IEC 61850-7-2 — ACSI, abstract communication services;
IEC 61850-7-3 — Common Data Classes;
IEC 61850-7-4 / 7-xxx — logical nodes and data objects.
That is, the changes mainly concern the model part related to logical nodes and data objects, not the whole IEC 61850-7 series.
In addition, model parts of the 7-4xx series existed earlier as well. For example, IEC 61850-7-410 is used for hydropower plants, and IEC 61850-7-420 — for distributed energy resources. The new structure continues this logic of thematic separation of the models.
Takeaway
The publication and closure of the CDV vote on the seven IEC 61850-7-xxx model documents show that the standard is continuing to evolve from a monolithic description of the models towards a more flexible, thematically separated structure.