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Electrical substations help manage how electricity is delivered from power plants to homes, schools, factories, etc. PhD student Nadine Kabbara investigated the application of virtualization technologies in these key parts of our power systems. “Virtualization makes the system more flexible, efficient, and easier to update or scale as needed. 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.” Nadine Kabbara will defend her PhD thesis on September 10th.

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 like 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 new digital technologies, these substations are becoming smarter, more efficient, and more connected than ever before.

Software-defined systems

Kabbara’s dissertation investigates the application of virtualization technologies in digital substations, with a focus on virtualized Intelligent Electronic Devices (vIEDs) and their integration into power system design and operations. Virtualization is a technology many of us use every day - like when you store photos in the cloud or stream a movie from a remote server. Instead of relying on a single physical device, virtualization creates a software-based version of a computer or service, which can be easily deployed.

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 virtualization, IEDs can also run as software on shared digital platforms in the electrical substation.

Flexibility

To start with, the work explores the why of the technology, emphasizing 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 smart grid technologies. Or as Kabbara puts it: “Just imagine how more relaxed you would be with a flexible train ticket compared to a non-exchangeable, non-refundable one; the same principle applies to flexible power system design.”

Compatibility

In her thesis Kabbara introduces a novel Model-Driven Engineering (MDE) framework for designing and configuring virtualized IEDs, ensuring compatibility with existing engineering standards, particularly the IEC 61850 international standard. This framework is 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 virtualized IEDs. A formalized test methodology was developed to address the lack of consistency in existing platforms, categorizing tests into communication, scalability, and functional configurations. 

Cybersecurity

To complete the picture, attention is also given to the cybersecurity implications of integrating virtualized and physical IEDs in a hybrid system. Assessing potential cyber vulnerabilities introduced by virtualization 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 cybersecurity by design for hybrid physical-virtual protection, automation, and control systems.

Cost savings

Lastly, she explored the economic feasibility of digital substations with virtualized IEDs. A techno-economic analysis reveals that virtualization in digital substations can provide significant cost savings, particularly in the long term. In the baseline scenario, virtualization offers a 20% reduction in capital expenditures (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 operational expenditures (OPEX).

Potential

The main conclusion of this work is that virtualization in digital substations has significant potential for improving flexibility and reducing costs in power system operations. This positive impact is dependent on overcoming challenges related to proper technology integration, such as configuration and interoperability, testing and benchmarking, and cybersecurity. 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 has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the InnoCyPES project (Innovative Tools for Cyber-Physical Energy Systems) and the Marie Skłodowska-Curie MSCA grant agreement No 956433.