The virtualisation of electrical substations could be the next step for making the power distribution backbone more flexible and scalable, according to research at Utrecht University in the Netherlands.

Electrical substations help manage how electricity is delivered from power plants to homes, schools, factories and so on. PhD student Nadine Kabbara investigated the application of virtualisation technologies in these key parts of power systems.

“Virtualisation makes the system more flexible, efficient and easier to update or scale as needed,” she said. “It also contributes to reducing costs in power system operations. These are all essential developments, given the big transitions that our electrical power systems are going through as we move towards a greener and more digital future.”

Substations perform several critical functions. They step up or step down the voltage of electricity so it can travel safely over long distances or be used locally. They also act as gateways, directing electricity along different paths in the grid and protecting the system against electrical or natural faults such as a fallen tree branch on a power grid line. Because substation systems manage how electricity moves across the entire network, they are often called the backbone of the power system. Thanks to digital technologies, these substations are becoming smarter, more efficient and more connected.

Kabbara’s dissertation investigates the application of virtualisation technologies in digital substations, with a focus on virtualised intelligent electronic devices (IEDs) and their integration into power system design and operations.

In the world of power systems, the same idea is being applied to the devices that monitor, protect and control electricity. Traditionally, these were individual physical devices installed in substations. Now, thanks to virtualisation, IEDs can also run as software on shared digital platforms in the electrical substation.

To start with, the work explores the why of the technology, emphasising its importance for the evolving needs of digital substations. Flexibility in IED design and operation emerges as a key motivation, driven by the integration of renewable energy sources and the need for more agile and interoperable methodologies to support smartgrid technologies.

Or as Kabbara puts it: “Just imagine how more relaxed you would be with a flexible train ticket compared with a non-exchangeable, non-refundable one; the same principle applies to flexible power system design.”

In her thesis Kabbara introduces a novel model-driven engineering (MDE) framework for designing and configuring virtualised IEDs, ensuring compatibility with existing engineering standards, particularly IEC 61850. This framework was tested for scalability and performance using real substation configurations, proving its preliminary effectiveness in large-scale deployments. She also tested and validated the performance of virtualised IEDs. A formalised test methodology was developed to address the lack of consistency in existing platforms, categorising tests into communication, scalability and functional configurations.

To complete the picture, attention was given to the cyber-security implications of integrating virtualised and physical IEDs in a hybrid system. Assessing potential cyber vulnerabilities introduced by virtualisation was performed.

Kabbara proposes a novel hybrid protection scheme, where both virtual (new) and physical (traditional) protection IEDs can be coordinated to backup each other to mitigate cyber threats. Her work reinforces the importance of cyber security by design for hybrid physical-virtual protection, automation and control systems.

Lastly, she explored the economic feasibility of digital substations with virtualised IEDs. A techno-economic analysis reveals that virtualisation in digital substations can provide significant cost savings, particularly in the long term. In the baseline scenario, virtualisation offers a 20% reduction in capex and a 60% reduction in update costs. However, the analysis also highlights the sensitivity of the financial outcomes to initial capex, licensing fees and opex.

The main conclusion of this work is that virtualisation in digital substations has significant potential for improving flexibility and reducing costs in power system operations. This positive impact is dependent on overcoming problems related to proper technology integration, such as configuration and interoperability, testing and benchmarking, and cyber security. By ensuring a smooth integration, virtual and physical substation devices can harmoniously co-exist in modern power systems, paving the way for a new paradigm.

This research at Utrecht University (www.uu.nl) received funding from the European Union’s Horizon 2020 Research & Innovation Programme under the InnoCypes (Innovative Tools for Cyber-Physical Energy Systems) project and the Marie Skłodowska-Curie MSCA grant agreement.