LTDS

The regulated DNO data publication that every network study starts from.

Every GB Distribution Network Operator publishes an annual Long Term Development Statement under Ofgem Standard Condition 25. LTDS v2-1-0 uses four CIM profiles (Equipment v7, Short Circuit Result v3, SYSCAP v5, Header v1) validated by SHACL constraints. This route explains what LTDS is, why it matters, and where the data quality gaps still sit.

19Route 19 · Data and standards
11 min read 4 sections 1 diagram 1 decision tool Last verified

After this route you will be able to

  • Explain what LTDS is and why every DNO must publish one annually.
  • Name the four CIM profiles in the v2-1-0 release.
  • Describe the role of SHACL validation in LTDS submissions.
  • Identify how LTDS supports connection studies, DSO planning and investor analysis.
  • Open the LTDS validator island to run your own file against Ofgem profiles.
Distribution substation equipment representing the assets LTDS catalogues

24 July 2025LTDS v2-1-0 released · first SHACL-validated publication

Thirty-nine official artefacts. Forty open issues. The most formal LTDS release to date.

For decades LTDS was a set of unstructured PDFs with tables. Every DNO published something different. Any third party wanting to analyse GB distribution data had to write per-DNO parsing code. Connection applicants, investors, researchers, each re-built the same tooling.

The 24 July 2025 release changed that. v2-1-0 is the first LTDS to use formally versioned CIM profiles, SHACL validation and a published release catalogue. Thirty-nine artefacts, forty tracked issues, four CIM profiles. Every DNO must submit conformant data or face Ofgem enforcement.

The release is not a reform of what DNOs publish. It is a reform of how they publish. The same underlying data, in a standard form, at a known cadence, validated by the same rules. That is the foundation every other digital-layer reform builds on.

Why does a data-format reform matter, and what does LTDS v2-1-0 actually require DNOs to publish?

The answer starts with the four profiles. Each profile covers a specific slice of the network model.

Section 01 · The four CIM profiles

Equipment, Short Circuit Result, SYSCAP, Header.

Each profile defines a chunk of the LTDS submission. The four combine into a complete DNO network picture.

Diagram 01 · LTDS v2-1-0 CIM profiles

EQ v7

Equipment

Physical assets: transformers, lines, switchgear, protection. Topology and ratings. The largest profile.

IEC 61970 derivation

SCR v3

Short Circuit Result

Computed short-circuit fault levels at each node. Used for equipment selection and fault-level headroom.

Calculation-driven

SYSCAP v5

System Capacity

Capacity, demand forecasts, headroom data. The profile most used by connection applicants and developers.

Forecast horizon: 5+ years

Header v1

Header

Metadata about the submission: DNO, release date, version, change log. The governance envelope around the data.

Required for every submission

Source: Ofgem LTDS v2-1-0 release catalog (24 July 2025). All profiles serialise as RDF/Turtle with SHACL validation rules.

Section 02 · What LTDS is for

Connection studies, DSO planning, investor due diligence.

LTDS is the standard input for every external analysis of a GB DNO network. Three use cases account for most of the traffic.

Connection studies. A developer proposing a new generator or large load submits an application; the DNO's network engineers model the impact. The published LTDS gives third-party consultants and the applicant's own team a starting point for understanding headroom and constraints before formal application.

DSO planning. The DNO itself uses the LTDS as the basis for its RIIO-ED2 reinforcement plan. Ofgem reviews the plan against the published data. Stakeholders can scrutinise whether proposed investment matches the evidence in the data.

Investor and researcher analysis. Pension funds, specialist lenders, academic researchers, policy analysts all use LTDS to understand network exposure and opportunity. Standardised, validated data makes cross-DNO comparison practical for the first time.

The LTDS validator (available as an island in this workspace) lets anyone run a submitted file against the Ofgem profiles. If the file passes, it is structurally conformant; if it fails, the validator pinpoints the shape violations.

Each Distribution Network Operator shall publish, by 31 December each year, a Long Term Development Statement. The statement shall provide sufficient technical information for interested parties to assess connection opportunities and plan operational decisions.

Distribution Licence Standard Condition 25 (Ofgem)

Section 03 · Working with LTDS

Build your own tools, use a vendor, or use the open validator?

Once LTDS data is in a standard form, the practical question is how to work with it. Three options with different costs.

Each option trades time against depth against cost. Use the open validator. Free and immediate. Contract a power-systems analysis vendor. Build the tooling in-house. The free validator is the right starting point for most teams. Upgrade only when volume or depth demands it. Start over This is the right answer for developers and DNOs doing serious study work. Start over Worth doing only if LTDS work is core to the team. Otherwise use the open validator or a vendor. Start over

Check your understanding

Three questions on what you have just read.

2 4 7 10 XML Schema JSON Schema SHACL RelaxNG Quarterly By 30 April each year By 31 December each year Only after RIIO price-control periods

Key takeaways

  • LTDS is the regulated annual DNO data publication. Mandatory under Ofgem SC25.
  • LTDS v2-1-0 (July 2025) uses four CIM profiles: Equipment, Short Circuit Result, SYSCAP, Header.
  • SHACL validates structural conformance. Non-conformant submissions are rejected.
  • LTDS is used for connection studies, DSO planning, and investor due diligence.
  • The LTDS validator island lets anyone check a file against the Ofgem profiles.

References

  1. Ofgem: Long Term Development Statement

    SC25 statutory requirement, release catalog, profile specifications.

    Primary regulatory source.

  2. W3C: Shapes Constraint Language (SHACL)

    RDF data validation standard.

    Validation standard reference.

  3. IEC 61968/61970 (CIM)

    Power system data model.

    Primary CIM reference.

Continue with the LTDS validator. Run your own files against the Ofgem profiles in the embedded tool.