Context

The massive integration of renewables, the rise of multi-terminal HVDC schemes, and the growing complexity of the European power system require robust network behavior simulation tools. TSOs increasingly need to anticipate system response to contingencies and to plan grid extensions involving both AC and multi-terminal DC infrastructures. This will help discover the bounds on multi-terminal DC networks functioning points and design new control mechanisms to overcome the constraints.

While several tools exist for load‑flow and OPF studies, their AC-DC capabilities are usually limited to point-to point HVDC links. Mature, aligned, and interoperable AC-DC modelling with multi-terminal DC networks is still lacking. Current HVDC and multi-terminal DC modelling practices do not yet ensure multi‑vendor interoperability, a known challenge when combining converters and control schemes from different manufacturers in hybrid AC‑DC grids with multi-terminal DC subnetworks. Achieving a shared understanding of AC‑DC interactions is therefore becoming a strategic necessity.

DC‑BL explores PowSyBl as a common, open-source and extensible simulation framework for AC-DC models with multi-terminals DC subnetworks. PowSyBl (Power System Blocks) natively supports CIM/CGMES formats, enabling consistent and interoperable data exchange between TSOs across Europe. Governed under LF Energy, PowSyBl benefits from a transparent, neutral governance model where an open Technical Steering Committee publicly reviews changes and sets the roadmap. The framework is already used operationally by several European TSOs and RCCs, including TSOs participating in CORESO, reinforcing its suitability as a shared foundation for developing advanced AC‑DC modelling capabilities.

Objectives

• Demonstrate the relevance of the PowSyBl platform for AC‑DC network simulations with multi-terminal DC subnetworks.
• Develop AC-DC load-flow computation capabilities integrating essential HVDC components.
• Extend the platform to new DC components and new compatible simulation types.
• Build concrete application demonstrators to validate the added value of the approach and support adoption by system operators.

Project Partners

• SuperGrid Institute (HVDC modelling and simulation expertise)
• Transmission System Operators:
  • TenneT Germany
  • TenneT Netherlands
• The project is open to additional partners.