FAST DC develops a vendor‑agnostic framework to enable advanced studies of multiterminal high-voltage direct current (HVDC) grids, with a strong focus on the modelling and system‑level assessment of DC circuit breakers (DCCBs). As HVDC networks evolve from point‑to‑point links to complex DC grids, effective and selective DC fault protection becomes a critical challenge. FAST DC builds on prior Network DC SIF work to deliver high‑fidelity electromagnetic transient (EMT) models, real‑time field-programmable gate array (FPGA) based simulation capabilities, and new analytical methods to evaluate advanced DCCB functionalities such as proactive interruption, current limiting, selectivity, and post‑fault stabilisation. The project will produce open‑source models and evidence‑based guidance to improve DC grid resilience, reduce reliance on proprietary tools, and support future multiterminal HVDC hubs and interconnectors.

Benefits

The project will deliver:
Lower bills for consumers

• Better informed specifications
• Broader capability for real-time simulation of other technologies, enabling future cost savings and enhanced performance.

Ensuring business security and reliability 

• Realistic breaker modelling strengthens security of supply for offshore wind and interconnector networks.
• Evidence-based specifications reduce operational uncertainty and technology performance risks.
• Real-time simulation capability supports more robust testing of control and protection schemes before deployment.

Better quality of service 

• Delivery of open-source EMT and real-time DCCB models, reducing reliance on OEM-specific tools and proprietary models.

Benefits for society as a whole

• Accelerates progress toward Net Zero by enabling secure, flexible and scalable multi-terminal DC grids.
• Development and testing of the FPGA-based platform will also inform approaches to real-time simulation of other technologies.

Supporting the Energy System Transition
The FAST DC project directly supports the UK’s energy system transition by developing the tools and evidence needed to enable future multi‑terminal HVDC grids. By creating open‑source, vendor‑agnostic models and advanced real‑time simulation capability, the project removes key technical barriers to effective DC fault protection and interoperable grid design. This work strengthens whole‑system planning, reduces reliance on proprietary approaches, and accelerates the deployment of flexible, reliable, and low‑carbon transmission networks essential for the decarbonised energy system of the future.