Public Consultation on the Assessment Framework for Pre-Qualification and Testing of 525 kV HVDC Land and Submarine Cable Systems

Overview

ENTSO-E invites stakeholders to provide feedback on a draft European assessment framework for the testing, qualification and range of approval of 525 kV HVDC cable systems.

Consultation Overview

Objective of the Consultation

ENTSO-E has developed a draft assessment framework for the prequalification, type testing and range of approval of 525 kV HVDC land and submarine cable systems.

The framework aims to provide a more harmonised technical basis for transmission system operators (TSOs) when assessing HVDC cable systems for European projects, while maintaining consistency with IEC standards and CIGRE recommendations.

The objective of the draft framework is to provide non-binding technical guidance that may assist TSOs and market participants in assessing testing, qualification and range-of-approval issues for 525 kV HVDC cable systems.

The framework is intended to improve transparency and predictability of technical assessment criteria, without harmonising procurement strategies, commercial terms, supplier selection, project timing, output, capacity, prices, costs, margins, allocation of projects, or any other competitively sensitive parameter.

The initiative seeks to:

• reduce unnecessary divergence between project specifications,
• increase predictability and transparency for manufacturers and TSOs,
• maintain a high level of technical confidence for critical infrastructure,
• support the accelerated deployment of European electricity grids.

The framework is intended to support a harmonised technical basis while continuing to allow for project-specific requirements, operating conditions and national regulatory obligations.

Use of the framework is voluntary and non-exclusive. TSOs, manufacturers, testing laboratories and other stakeholders remain free to develop, propose, assess, accept or reject alternative technical solutions, qualification approaches or project-specific requirements, provided that decisions are made independently and on objective, transparent, proportionate and non-discriminatory technical grounds. 

Context

This work was initiated in response to the European Commission Grid Action Plan and contributes to Action Point 1.3 of the Joint Roadmap Towards Future-Proof Grids.

The roadmap identified the need to review diverging qualification and testing practices for HVDC cable systems and encouraged closer cooperation between TSOs and manufacturers to improve harmonisation and procurement efficiency.

For information: Joint Roadmap Towards Future-Proof Grids

The ENTSO-E work has also been coordinated with CIGRE TF B1.97 in order to support consistency with ongoing international technical work and avoid duplication of effort.

(CIGRE TF B1.97 is an international technical task force operating under CIGRE Study Committee B1 (“Insulated Cables”). The task force focuses on improving and clarifying Range of Approval criteria for high-voltage and extra-high-voltage power cable systems, including HVDC applications. Its work aims to support greater consistency in qualification methodologies, interpretation of testing requirements and extension-of-qualification approaches across the industry.)

Scope of the Framework

The assessment framework currently covers:

• extruded underground and submarine HVDC cable systems up to and including 525 kV,
• cable accessories,
• prequalification testing,
• type testing,
• extension of qualification,
• and range of approval methodologies.

The work currently focuses on HVDC systems. Assessment of harmonisation potential for HVAC cable systems may be considered at a later stage.

Main Outcomes Achieved So Far

Harmonisation of Prequalification & Type Testing

The ENTSO-E working group achieved substantial harmonisation across participating TSOs regarding prequalification testing programmes and associated technical approaches.

The work included:

• evaluation of 21 prequalification testing items,
• harmonisation on 15 items, compared to 4 items harmonised at the start of the process,
• identification of remaining open items requiring further discussion.

The following topics were also discussed:

• test loop configuration,
• spacing requirements,
• mechanical preconditioning,
• sheath testing,
• long-duration voltage testing,
• interruption and re-testing principles.

ENTSO-E considers harmonisation of prequalification testing programmes to be particularly valuable due to the long duration, complexity and resource intensity of these tests.

At the same time, several topics remain under discussion, including:

• test object selection,
• fixation approaches,
• dummy loop arrangements,
• and certain submarine-specific aspects.

Harmonisation on Range of Approval

ENTSO-E also developed a common technical position regarding extension of qualification and the application of Range of Approval principles based on CIGRE TB 852.

The work aimed to improve clarity and consistency in the application of the CIGRE TB 852 Range of Approval principles, with the objective of reducing unnecessary technical discussions and supporting a more efficient qualification process.

The working group:

• evaluated 122 range-of-approval items,
• identified areas where existing guidance is insufficient,
• identified gaps and areas requiring clarification,
• and developed harmonised technical positions to support further industry discussion.

The work covers:

• cable systems,
• cables,
• accessories,
• and submarine-specific applications.

Particular attention was given to:

• HVDC cable accessories,
• extension of qualification methodologies,
• submarine cable systems,
• and consistency of qualification approaches across projects.

The ENTSO-E range of approval tables have also been shared with CIGRE TF B1.97 as technical input for ongoing international work.

Stakeholder Involvement

The work has involved collaboration between:

• European TSOs (including participants from CIGRE TF B1.97.)
• Europacable,
• ENTSO-E experts,

The work included multiple technical workshops and discussion sessions conducted since summer 2025.

Scope of the Consultation

ENTSO-E welcomes feedback from:

• cable manufacturers,
• TSOs,
• engineering companies,
• testing laboratories,
• industry associations,
• regulators,
• and all other interested stakeholders.

Feedback is particularly encouraged on:

• practicality of the proposed framework,
• opportunities for technical harmonisation,
• range of approval methodology,
• treatment of accessories and submarine systems,
• harmonisation with existing standards and industry practice,
• and implementation considerations.

At this stage, the consultation aims to gather industry feedback to support further refinement of the framework and identification of remaining open technical topics.

Consultation Material

The consultation package includes:

• Draft ENTSO-E Assessment Framework for 525 kV HVDC Land and Submarine Cable Systems
• ENTSO-E Draft Position on Range of Approval for HVDC Cable Systems

How to Provide Feedback

Stakeholders are invited to:

1. review the consultation documents,
2. assess the proposed technical approaches,
3. provide comments and technical feedback,
4. submit responses through the consultation platform.