PROMOTioN seeks to develop meshed HVDC offshore grids on the basis of cost-effective and reliable technological innovation in combination with a sound political, financial and legal regulatory framework.


The project ‘PROgress on Meshed HVDC Offshore Transmission Networks’ (PROMOTioN) applied in 2015 for funding under the EU Horizon 2020 (H2020) programme call ‘Competitive Low-Carbon Energy’ 5 (LCE 5). Within the framework of modernisation of the European electricity grid, this call focused on advancing innovation and technologies relevant to the deployment of meshed HVDC offshore grids. Its specific objective is to pursue an agreement between network operators and major equipment suppliers regarding a technical architecture and a set of multi-vendor interoperable technologies in order to accelerate HVDC grid development.

PROMOTioN actively addresses the objectives that LCE 5 encompasses. Specifically, these are to:

  • Identify requirements for energy infrastructure priority corridors
    The requirements embrace a broad range of issues, such as the design, development and deployment of the energy infrastructure from a technical, financial, regulatory, management and policy perspective.
  • Facilitate agreement among operators and manufacturers
    Manufacturers and operators need to agree on architectures, control structures and interfaces in order to ensure interoperability and multi-vendor compatibility of equipment.
  • Prepare the first phase for deployment of innovative components…
    … of interoperable meshed offshore HVDC network technologies, services and tools architectures.
  • Propose market rules and revenue streams…
    … to help establish a suitable package of financial resources
  • Propose regulations for permitting and environmental compatibility
    PROMOTioN aims to set up a regulatory framework for operation and management of meshed offshore grids governing legal, technical, and market-related aspects.


A meshed European offshore transmission grid connecting offshore wind farms to shore could provide significant financial, technical and environmental benefits to the European electricity market. Launched in January 2016, PROMOTioN aims to explore and identify these potential benefits.

The main objective of PROMOTioN is the further development and demonstration of three key technologies: diode rectifier offshore converters, multi-vendor HVDC (high-voltage direct current) grid protection systems, and full power testing of HVDC circuit breakers. Complementary to this end, a regulatory and financial framework will be developed for the coordinated planning, construction and operation of integrated offshore infrastructures, including an offshore grid deployment plan (roadmap) for the future offshore grid system in Europe.

Currently, the high cost of converter technology, and a lack of experience with protection systems and fault clearance components, hamper the deployment of meshed HVDC offshore grids. In addition, deployment is hindered by limitations inherent to existing European regulations regarding the development of cross-border offshore infrastructures, national legal and regulatory barriers, and financing issues.

Timetable and Work Packages

PROMOTioN runs over a period of four years. The project is organised in a total of 14 work packages (WP‘s), which are closely interlinked. Laying the foundation by identifying the requirements for meshed offshore grids, WP 1 commenced with the kick-off of the project. WP 2-7 build upon the findings of WP 1 with the implementation of requirements for the project and examination of specific technology issues in detail. These range from grid topology to grid protection systems (WP 2-6) as well as regulatory aspects and financing (WP 7). On the basis of WP 2-6, WP 8-10 implement demonstrator and pilot facilities after completion of WP 2-6, in turn leading to WP 11 which addresses harmonization towards standardization. The results from WP 7 and 11 will jointly determine the development of a final deployment plan for the future meshed HVDC offshore grid. The project is flanked by WP 13 and 14, which have the task of dissemination (13) and overall project management (14).

Work package overview
Work package overview

Work package 1 worked on the requirements and defining a common starting point for the project, which in itself creates few newsworthy events. However, the work proved very valuable in the execution of the project itself. The PROMOTioN project is a multidisciplinary project with a large amount of partners. The contribution of WP1 is to bring together all these disciplines and different organizations and develop a shared understanding of the complexities of developing a meshed DC grid offshore. As all other work packages that started in year 1 have a smaller scope (e.g. focusing on a particular parts such as DC circuit breakers, DC circuit breaker testing, protection, finance & regulation etc.), WP1 was the place to discuss the overall view and the complexities of putting everything together. By having these discussions the WP laid important groundwork for the PROMOTioN project and particularly the outcomes that will come at the end of the project.

The first deliverable (D1.1) was a qualitative set of requirements for meshed offshore grids. Additionally WP1 performed a literature review (D1.3) to harvest the knowledge that has been gathered by other studies, and collected lessons learned from real life projects (D1.2). Jointly, these tasks ensured an optimal absorption of prior meshed offshore grid knowledge into the PROMOTioN project and its consortium. With this data, WP1 delivered preliminary grid topologies, supported by a simplified Cost Benefit Analysis (D1.4). These basic topologies were not intended as final grid structures, but as common test-topologies, which can be used for modelling purposes throughout the project. Furthermore, this work package delivered a starting list of quantified requirements. These requirements were also not set in stone, but are, similar to the topologies, used as a common starting ground (D1.5). After the first two years of the project, WP1 has ended with a completely revised Quantification List (D1.7).


Download Deliverable 1.1: Detailed description of the requirements that can be expected per work package (PDF 2.6 MB)

Download Deliverable 1.2: Report documenting results of the questionnaire on best practices (PDF 4.0 MB)

Download Deliverable 1.3: Synthesis of available studies on offshore meshed HVDC grids (PDF 4.0 MB)

Download Deliverable 1.4: Report with reference scenario and related offshore meshed HVDC grid topology (PDF 1.0 MB)

Download Deliverable 1.5: Quantification of requirements (PDF 2 MB)

Download Deliberable 1.6: Draft roadmap and reference offshore grid expansion plan (PDF 6 MB)

Download Deliverable 1.7: Report on the re-evaluation of the requirements based on results by other WPs (PDF 3.4 MB)

The overall objective is to perform a trade-off analysis and compare different topologies using complex simulation analysis. Interoperability, specifically of diode rectifiers and converters, is investigated by running steady-state, dynamic and transient simulations, thus demonstrating the functionality of these topologies. The results on interoperability as well as control of converters and diode rectifiers, both during normal operation and fault scenarios, are reported and guide the construction and operation of a demonstrator in WP 8 and the definition of requirements for a full scale commercial application in WP 12. In addition, the measured effect of different offshore topologies on the onshore AC grid (e.g. frequency stability) contribute to WPs 8 & 12 in the same manner. Furthermore, WP 2 serves as direct input for WP 11 in order to preserve a close link to current harmonization activities and strongly interacts with WP 3 via joint studies.

The main objective of WP 3 is to identify and specify appropriate analyses and to demonstrate interoperability of wind turbine and wind power plant controls with two different types of HVDC systems for connecting the wind power plants to the DC network: diode rectifiers (DR) and VSC converters. The in-depth study included in this WP, will however be based on models for wind turbine and wind power plant controllers, which are intended to be manufactured independently as ‘black box model’ by participating wind turbine manufacturers, with the focus mainly on the novel DR-HVDC link. At the same time, WP3 will provide input to WP11 in the form of recommendations for good practice on how generic open models could be structured. Furthermore, WP 3 gives direct input to WP 8 and extensively interacts with WP 2, as various studies are conducted cooperatively.

Download Deliverable 3.1: Detailed functional requirements to WPPs (PDF 2 MB)

Download Deliverable 3.2: Specifications of the control strategies and the simulation test cases (PDF 2.5 MB)

Download Deliverable 3.4: Results on control strategies of WPPs connected to DR-HVDC (PDF 2 MB)

Download Deliverable 3.5: Performance of ancillary services pro-vision from WFs connected to DR-HVDC (PDF 850 KB)

This WP aims to further develop the most appropriate DC grid protection methodologies for various system topologies. Making use of the reference grids and parameters from WP 1 and WP 2, functional requirements and appropriate tests for the selected topologies are developed. Currently, a wide range of protection methods are proposed, which will be screened and compared using these test methodologies. Of these, the most promising are selected for development towards practical implementation, which includes specification of the protection equipment and the required measurement equipment, post-fault recovery, backup, interoperability, etc.. To implement the different methods in the demonstrator (WP 9), an Intelligent Electronic Device (IED) or protection relay is designed. This device will be able to accommodate the different protection methods and can be connected to the MTTE facilities. The work package will also prepare input for WP 11 in the form of a summary of the performance parameters of the selected DC grid protection systems. Interoperability and failure modes of selected protection methods will be determined, and the factors affecting the cost-benefit analysis will be summarized.

Download Deliverable 4.2: Broad comparison of fault clearing strategies for DC grids (PDF 15 MB)

The WP objectives are:

  • To identify worst case situations of faults from grid simulations in an internationally recognized benchmark meshed DC grid.
  • To produce dynamic, black-box models of DC circuit breakers of technologies as applied by the partners, including their relevant functions
  • To embed these models in the benchmark system in order to quantify the electrical stresses (current, voltage, energy) to which high-voltage DC circuit breakers are subjected in case of fault.
  • To design, by simulation, test-circuits that produce stresses equivalent to those in service, based on existing high- power generator sources as present at DNV GL. Since these test-circuits are by their nature supplied by AC sources, test-circuits must fulfil requirements that stress all circuit breakers parts adequately during the total interruption process. The interaction of DC circuit breakers with the test-circuit will be quantified for each technology of DC circuit breaker.
  • To realize real high-power test-circuits including the necessary equipment (components) specifically needed for DC testing.


Download Deliverable 5.1: HVDC Network Fault Analysis (PDF 1.4 MB)

Download Deliverable 5.3: Fault Stress Analysis of HVDC Circuit Breakers (PDF 4.2 MB)

Download Deliverable 5.4: Documents on test requirements (PDF 1.1 MB)

Download Deliverable 5.5: Documents on test procedures (PDF 567 KB)

Download Deliverable 5.6: Software and analysis report on candidate test-circuits and their effectiveness (PDF 2.6 MB)


Download the Presentations held at the TSO Workshop of WP5 (ZIP 11.0 MB)

Download the summary of WP 5 (PDF 1.5 MB)

This WP studies in depth commercial DC CB (direct current circuit breaker) topologies. It will complement DC CB demonstration activities in WP5 and WP10, since it develops software models that can be used for fast and flexible studies of DC CBs. Small-scale hardware models will also be developed to facilitate characterisation of some aspects that cannot be analysed well with simulation models. The WP will further provide real-time DC CB models for DC grid demonstration in WP9. In the last stages, the researchers will work on the roadmap for increasing voltage levels and enhancing DC CB technology.

The objectives of this WP are:

  • To develop and verify system-level off-line and real-time model for hybrid and mechanical DC CB,
  • To develop and verify detailed component level model for hybrid and mechanical DC CB,
  • To develop and verify kW-size hardware prototypes for hybrid and mechanical DC CBs,
  • To demonstrate DC CB failure modes on kw-size hardware prototypes,
  • To develop roadmap for hybrid DC CB scaling to EHV DC voltage,
  • To develop roadmap for mechanical DC CB scaling to EHV DC voltage.


Download Deliverable 6.1: Develop system level model for hybrid DC CB (PDF 2.0 MB)

Download Deliverable 6.2: Develop system level model for mechanical DCCB (PDF 716 KB)

The current EU framework does not provide specific rules for an interconnected and integrated offshore electricity grid. So far, the focus of the EU framework has been on the regulation of point-to-point interconnectors. Also, clarity on the appropriate financial regulatory model of such an interconnected grid is still lacking, while a meshed North Sea grid comes at high cost and risks. Hence, the main objective is to develop the appropriate European regulatory target framework for the development of integrated offshore electricity transmission infrastructures. This requires a solid framework with different legal, economic and financial properties.

Different recent studies identify the main political, legal and regulatory barriers and investigated the needs for a particular EU regulatory framework to support the deployment of offshore grids in a 2020 policy perspective. WP7 will build on those studies and on the work that is ongoing for the implementation of the first energy infrastructure package (TEN-E Regulation), which includes the development of a Cost Benefit Analysis method; regulatory procedures on Cross-Border Cost Allocation, TSO incentives, and EU funding under the Connecting Europe Facility. This also includes the Energy Union initiatives, such as interconnection targets and the European Fund for Strategic Investments.

Download Deliverable 7.1: Legal framework and legal barriers to an offshore HVDC electricity grid in the North Sea (PDF 2.7 MB)

Download Deliverbale 7.3: Economic framework for offshore grid planning (PDF 2.8 MB)

Download Deliverable 7.5: Financing framework for meshed offshore grid investments (PDF 1.2 MB)

Download Deliverable 7.7: Intermediate Stakeholder Report (PDF 1.5 MB)

The work package aims to develop and build a Windfarm Demonstrator plant to demonstrate the diode rectifier technology used for connecting offshore windfarms to the onshore grid and future DC grids. It shall proof the functionality and feasibility of the new technology. This applies for each individual piece of equipment from the turbine up to the new developed Diode Rectifier Unit (DRU) which converts the offshore AC power into DC power for transmission to shore. A new wind turbine controller maintains voltage and frequency in the offshore grid, as there is no VSC control existing any more. The only active partners offshore will be the turbines. System parameters and/or equipment are adjusted or simulated as required, presuming that the wind farm is located far offshore. It also includes the development and possible manufacturing of a hybrid submarine cable prototype combining AC and DC cores in one jacket.


  • Investigate and compare different technical options on how the prototype can be realized
  • Develop a design with dependable cost estimates
  • To decide on GO/NO GO for the realization of the plant and if applicable
  • To manufacture and assemble the equipment and demonstrate functionality through tests i.e. proper turbine – rectifier interaction



The objective of this WP is to demonstrate operation of the DC grid protection systems developed in the project using hardware in the loop real-time methods. This WP will integrate results from DC CB modelling (WP 6 and WP 10) and DC protection development (WP 4) including hardware prototype of relay at The National HVDC Centre facility (Scotland) and demonstrating DC Grid protection system interoperability.

The specific objectives of WP 9 are:

  • To integrate DC relays from WP 4 and DCCB models from WP6 in RTDS environment.
  • To develop DC grid benchmark models and test procedures for protection system testing.
  • To demonstrate protection system performance using hardware in the loop real-time testing in RTDS.
  • To demonstrate primary and back-up DC Grid protection and system level consequences of protection failure.
  • To demonstrate equipment interoperability by testing DC protection systems from different manufacturers through various simulations.
  • To develop DC grid protection testing procedures.



The WP objectives are:

  • To demonstrate the correct functioning of full-power AC based test-circuits regarding their capability to generate adequate stresses to all available DC test-objects, incl. prototypes and scale models
  • To perform tests on the available test-objects, prototypes and scale models
  • To evaluate interaction between the HVDC circuit breaker (and other identified related critical components) and its electrical environment regarding steady state DC current, rate-of-rise of fault current, current interruption, fault current commutation, counter voltage generation and energy absorption
  • To acquire detailed information on various “microscopic” physical processes during the fault clearing process, to be supplied to studies in WP6
  • To perform current-zero analysis on arc-based HVDC circuit breaker demonstrators, to be supplied to studies in WP6
  • To analyse and quantify failure modes of selected sub-components, supported by input from WP6.
  • To demonstrate full-power testing on HV DC circuit breakers of participants
  • To initiate standardization activities.

The overall objective of WP11 is to support and establish harmonization of the industry’s best practices, standards and requirements for HVDC systems and HVDC connected offshore wind power plants.
WP 11 aims to ensure that the experience collected through the project – including research and engineering in WP 2-6, and demonstrations in WP 8-10 – is utilised in ongoing and future standardisation work.
WP11 aims to harmonize the work in existing and future working groups in IEC, CENELEC, CIGRE, and in national grid codes as well as the European grid code. Several of those working groups are covering overlapping topics, and there is a need to ensure that this work is aligned.
WP11 includes the main HVDC system manufacturers and thereby ensures that the different manufacturer concepts are considered in the relevant working groups.
The more specific objectives of WP11 are:

  • to provide a consistent and harmonized set of functional specifications to HVDC systems, wind power plants and other AC systems connected to the HVDC systems;
  • to recommend test procedures for converters, protection systems / components, wind turbines and wind power plants;
  • to provide functional specifications for models of HVDC systems and wind power plants connected to HVDC systems;
  • to recommend best practice for compliance validation of wind power plants connected to HVDC systems.



The key objective is to produce a Deployment Plan for European future offshore grid development. This plan will clearly define all required technical, regulatory, economic, financial, legal, governmental and market actions. Further objectives:

  • To evaluate results of all work packages and to identify key required technical, regulatory, economic, financial, legal, governmental and market barriers;
  • To collect relevant data and underlying grid development scenario’s to identify a ‘optimal scenario’ for the development of a future European offshore grid and its integration with the on-shore grid;
  • To analyse the economic and financial viability of results and recommendations of the different work packages and to develop a business case;
  • To integrate the current PROMOTioN project and past project results in a final deployment plan for future European offshore grid development.

Download Deliverable 12.1: Preliminary analysis of key technical, financial, economic, legal, regulatory and market barriers and related portfolio of solutions (PDF 3.5 MB)

  • To disseminate project findings to all target and stakeholder groups and the wider public via project, website and reports, workshops and stakeholder consultation as well as media activities and social media channels
  • To raise awareness about the potential and cost/benefits of meshed HVAC/DC offshore grids
  • To communicate innovative technology demonstrator solutions to key decision makers
  • To inform policy makers about recommendations for a coherent EU and national regulatory framework for meshed and cross-border offshore grid solutions
  • To discuss an action plan for the HVDC grid implementation, including the EU PCI project ISLES as one of the test cases (a letter of encouragement declares that access to ISLES project data is provided)
  • To facilitate and organise a dialogue between policy and industry stakeholders to accelerate DC offshore grid development (via the Reference Group consisting of key industry stakeholders and national/European policy-makers and regulators).

Download Deliverable 13.5: Executive summary of project interim report (PDF 969 KB)

The main objective of this work package is to meet the overall project goals within time and budget.
Accompanying objectives are:

  • to coordinate the project activities and decisions to be taken at milestones
  • to set up an effective management framework for the consortium
  • to report to the EU
  • to ensure proper cooperation and synergy between the WP's