As transmission systems grow more complex, simulation alone is no longer enough to prove that new technologies are ready for the grid. At KU Leuven in Belgium, researchers are using real-time simulation to bridge the gap between offline studies and full-scale deployment.

Professor Dirk Van Hertem leads research into how transmission systems will develop towards 2050, with high-voltage direct current (HVDC) as a key player. He is also Director of the Energy Transmission Competence Hub and Chair of the IEEE HVDC and FACTS subcommittee, and he helps coordinate the HVDC R&D roadmap within Europe’s SET Plan.

Why simulation alone is no longer enough

Offshore grids, electric vehicles and new technologies are driving rapid change in the power system. In the past, offline simulations and generous system margins were often sufficient. Today, systems are being pushed closer to their limits, and increasingly complex equipment is being added to networks that were once much simpler.

“It’s good to a certain stage, but at some point you need to do a little bit more to be sure,” says Van Hertem. “Of course you’re sure if you put it in a system, but that’s vastly expensive, so there is an intermediate stage.” For his team, that intermediate stage is real-time simulation.

Testing the first DC grid protection relay

One of the team’s key use cases is DC grid protection. In a DC grid, a faulted element must be identified and disconnected, which requires a relay that can determine whether a fault has occurred and whether it is responsible for clearing it.

The team developed protection algorithms and, together with KTH in Sweden, built a relay to implement them. The RTDS Simulator was used to run a range of test profiles and confirm the device met its functional requirements. As far as the team knows, it was the first DC relay ever developed.

The team then tested a next-generation DC relay developed by Mitsubishi Electric under similar functional specifications, which also met the requirements. A larger system test followed at a different location using hardware replicas of the HVDC system, completing a full chain of validation for the technology over time.

A safe environment for digital substation interoperability

The second project looked at digital substations. Although often described as a breakthrough, few system operators had adopted them, seeing them as risky. Interoperability was claimed but not guaranteed.

The team built a setup with equipment from different vendors side by side and brought vendors and users together to make it work. Initially, the system was not plug and play. But because the environment was accessible to multiple parties, and nothing on a live system could be disrupted, it became a space for open discussion and for developing guidelines for multi-vendor interoperability.

“It was found to be very interesting from the user side, who now say, ‘okay, it’s possible, we can do it,’ but also from the vendor side, who typically were not testing with someone else’s equipment,” says Van Hertem. “That’s a safe testing environment for research, but also for industry.”

Learn more by watching the video here