Projects are expected to implement the activities in (1) and the practical demonstration in (2) as described below:

1. R&I, methodologies and tools involving the activities in the three subtopics (A, B and C) listed below. These can be developed/complemented with others pertinent to each sub-topic.

A) DC – AC / DC hybrid system Design & Planning

a. Demonstration of software tools for transnational AC/DC hybrid power system planning and management to enable HVAC/HVDC/MVDC/LVDC hybrid systems, such as:

• integration of multi-terminal HVDC systems, both offshore and onshore and HVDC links embedded within the HVAC network as well as HVDC ties (inter-) connecting different control zones and synchronous areas (in full or in back-to-back schemes);
• representation and modelling of transmission and distribution grids as well as multi-energy vector integration (sector coupling) for long-term and for transient and dynamic analysis.

b. Demonstration of reliability and resilience methodologies to address security and adequacy issues and criteria via not only deterministic but also probabilistic (e.g., Monte-Carlo) methods.

c. Demonstration of developed methodologies and requirements for interoperability among Multi Terminal, Multi-Vendor MVDC and LVDC systems.

B) AC and DC Grid Forming Capability

• Functional requirements and demonstration of grid forming capability for hybrid HV AC/DC networks (e.g., offshore wind, HVDC transmission or multi-terminal HVDC grid, potentially associated with energy storage systems).
• Functional requirements and demonstration of grid forming capability for hybrid MV and LV AC/DC networks (grid connected and islanded operation with distributed energy sources).
• Functional requirements and validation procedure for testing grid-forming capabilities offered by HVDC, MVDC and LVDC systems.

C) DC Distribution & microgrids

• Modelling (steady state and transient models) for systems including different typology of RES, EVs, storage and loads (system architecture, voltage level, control, stability, protection, and storage integration).
• Planning and design of MVDC distribution grids as the intermediate layer between the HVDC and the AC or DC Low Voltage local distribution grid and loads.
• Functional requirements for the AC-DC converters, DC-DC converters, switchgear (including protection equipment) and cables based on the different typologies and power rating applications

2. Demonstration, test and validation of the activities developed in (1) in at least three pilots – one for each sub-topic (A, B and C) – in different EU Member States/Associated Countries.

International cooperation with countries of the Mediterranean Region is encouraged.