IEC 61850 information model

IEC 61850 is two things: an information model that standardizes what the data in a power system device means, and communication services with mappings that move it (MMS for client/server, GOOSE and Sampled Values for fast peer-to-peer traffic). This guide covers the model. For the communication side, see IEC 61850 / MMS.

go-iec61850-model implements the model in Go, with no transport: it imports the official namespace definitions, builds an edition-aware catalog, validates and resolves references, and adds rule-based semantic hints. nsdctl is the command-line tool included with it.

The model

Concept	Defined in	Example
Logical node class	IEC 61850-7-4 and domain parts (7-410, 7-420, technical reports 90-x)	MMXU measurement, XCBR circuit breaker, DBAT battery
Data object	The logical node class, with a CDC and a presence condition	MMXU.TotW of CDC MV, optional
Common data class (CDC)	IEC 61850-7-3	MV, WYE, DPC, ENS
Data attribute	The CDC, with a type and a functional constraint	mag (AnalogueValue, MX), q (Quality), t (Timestamp)
Functional constraint	IEC 61850-7-2	MX, ST, CO, CF, SP, DC
Enumeration	7-3, 7-4 and domain parts	SIUnitKind, MultiplierKind, BehaviourModeKind

Logical node classes inherit from abstract classes, so MMXU holds data objects it does not declare itself; go-iec61850-model returns the flattened list and says which class declares each one. Some CDCs leave an attribute’s type open (ENS.stVal takes the data object’s enumeration), and multi-instance data objects appear numbered on devices (Ind becomes Ind1, Ind2); the resolver handles both.

NSD files and editions

IEC 61850-7-7 defines NSD, the XML format in which IEC publishes each namespace as a code component. A namespace has a release identifier such as IEC 61850-7-4:2007B6 (version, revision and release, not a publication date) and declares the namespaces it depends on.

go-iec61850-model never picks a “latest” release. A catalog can hold several releases; a profile selects at most one release per standard and adds dependencies when exactly one loaded release satisfies them. A name that two namespaces define is never merged: IEC 61850-7-420 and IEC TR 61850-90-9 both define DBAT, differently, so a lookup in a profile with both fails as ambiguous until you name the namespace.

The library embeds a catalog of the 12 official NSD namespaces, generated from the official packages:

Profile	Namespaces
default	IEC 61850-7-2, 7-3, 7-4, 7-410 and 7-420
extended	The default namespaces plus the technical reports 90-3, 90-4, 90-6, 90-9, 90-11, 90-14 and 90-21

You can also load NSD packages you obtained yourself, as ZIP archives, directories or files. The importer treats them as untrusted: it bounds size, depth and token count, rejects DTDs, and checks archives for traversal and compression bombs. The service namespace of IEC 61850-8-1 is recognized but not modeled.

Normative model, device instance, interpretation

Level	Question	Where the answer comes from
Normative model	Does MMXU define Hz, and what type is Hz.mag.f?	The NSD namespaces, through go-iec61850-model
Device instance	Does this IED have LD0/MMXU1.Hz?	Its SCL file or browsing it over MMS with go-iec61850
Semantic inference	Is it a frequency, expected in Hz?	go-iec61850-model’s semantic package, from explicit rules

Semantic descriptors carry the rule, source and confidence they came from and are always marked as OT Fabric’s interpretation. No rule means no description: nothing is guessed from parts of names. The default rules cover MMXU, MMXN and MMTR. A unit hint is what a quantity is usually expressed in, not what a device reports; read the device’s own units attributes for that.

Install

go get github.com/otfabric/go-iec61850-model

Go 1.24 or later. The library packages use only the standard library and need no network access at run time.

Look up and resolve

main.go

p, err := official.Default() // IEC 61850-7-2, 7-3, 7-4, 7-410 and 7-420
if err != nil {
  log.Fatal(err)
}

// What does MMXU hold, inherited data objects included?
dos, _ := p.DataObjects("MMXU")
for _, do := range dos {
  fmt.Printf("%-8s %-4s %s\n", do.Name, do.Type, do.Presence)
}

// Resolve a device reference down to its basic type.
res, err := resolver.New(p).ResolveString("LD0/MMXU1.PNV.phsA.cVal.mag.f[MX]")
if err != nil {
  log.Fatal(err) // errors.Is(err, model.ErrUnknownDataObject), ErrAmbiguousReference, ...
}
fmt.Println(res.DataObjectPath(), res.AttributePath(), res.Type(), res.FC()) // PNV.phsA cVal.mag.f FLOAT32 MX

References follow the format of go-iec61850’s ParseRef (LD/LN.DO.DA[FC]), and the test suite runs go-iec61850’s own vectors against the parser. reference.FromMMS and Ref.ToMMS convert to and from the MMS form (domain LD0, item MMXU1$MX$PNV$phsA$cVal$mag$f).

Validation has three levels: syntax (reference.Parse, no model needed), model (resolver.Resolve against the selected namespaces) and device, which only SCL or discovery can answer.

Choose a namespace

x, _ := official.Extended()
_, err := x.LogicalNode("DBAT") // errors.Is(err, model.ErrAmbiguousSymbol): 7-420 and 90-9
dbat, _ := x.LogicalNodeIn(model.NamespaceID{Standard: "IEC 61850-7-420"}, "DBAT")

catalog.Overlaps compares the names two namespaces both define, classified as identical, compatible extension or conflicting.

Describe a value

d, _ := semantic.Describe(p, "MMXU.PNV.phsA.cVal.mag.f")
fmt.Println(d.Quantity, d.Phase, d.Reference, d.UnitHint) // voltage A line-neutral V

semantic.FindMeasurements lists the mapped measurements of a class, and a Mapper takes your own rules and overrides next to the defaults.

Generated names

ref := string(names.MMXU_PhV) + ".phsA.cVal.mag.f" // "MMXU.PhV.phsA.cVal.mag.f"
mode := names.BehaviourModeKind(1)                 // mode.String() == "on"

Package names has typed constants for every class, data object, CDC and enumeration of the default profile.

Packages

Package	Purpose
model	Namespaces, logical node classes, data objects, CDCs, data attributes, enumerations, FCs, presence conditions, provenance and errors
nsd	Importer for NSD and NSDoc XML and ZIP packages
catalog	Multi-release index, profiles, namespace-qualified lookups, overlaps, search and diff
reference	Instance and class references, logical node names, MMS form
resolver	Path and type resolution with provenance
semantic	Quantity, phase, reference, component and unit hints from explicit rules
ontology	Typed concept graph with traversal and JSON export
official	The embedded official namespaces and profiles
names	Generated constants of the default profile

The module imports neither go-iec61850 nor go-mms, nor any other transport.

Status and scope

go-iec61850-model is pre-release (v0.1.1 at the time of writing). Its README and PROGRESS.md track the state of each part.

• Supported: the NSD importer, catalog and profiles, references, type resolution, semantic mapping for metering classes, ontology helpers, the embedded catalog, generated names and the nsdctl CLI. The importer is tested against the 14 tracked official packages, and 93% of the concrete data objects resolve to leaf types; the rest hit gaps in the published packages.
• Not supported: MMS, GOOSE, Sampled Values or any other communication; an SCL runtime; the IEC 61850-8-1 service namespace. An NSD update monitor is planned.

IEC content and licensing

The library is MIT-licensed and ships no NSD files and no text from the standards. Its embedded catalog, the names constants and the generated model reference hold identifiers, types and structure derived from the official packages, published under the IEC Code Components licence with IEC attribution. Packages you load yourself stay under their own licence, and nothing here grants rights to the IEC standards. See docs/licensing.md in the repository.

nsdctlLook up classes, explain references and work with NSD packages from the command line.

IEC 61850 / MMSThe communication side: services, the MMS mapping, reports and controls. go-iec61850, go-mms.