Modeling for cyber-physical risk assessment

The CYPRESS project aims at developing novel knowledge, methods and tools needed to help en-
sure the security of supply through the transmission grid, while accounting for the specific nature
of cyber-threats and integrating them into a coherent probabilistic risk management approach. It is
articulated along three research themes, aiming to develop: i) novel models and benchmarks for com-
puter simulation and laboratory testing of the cyber-physical electric power system security of supply,
ii) techniques for assessing the cyber-physical security of electric energy supply, and iii) techniques for
enhancing the cyber-physical security of electric energy supply. The project scope falls entirely within
the category of “fundamental research” within the meaning of Regulation (EU) No 651/2014 because
it is experimental and theoretical work undertaken essentially with a view to acquire new knowledge
on the foundations of phenomena or observable facts. The project is not intended to develop com-
mercial tools.
The work presented in this document has been performed in the frame of CYPRESS WP2, titled
“Cyber-physical risk assessment of transmission systems”. The objective of CYPRESS WP2 is to de-
velop a coherent methodology for the ex ante assessment of the cyber physical risks facing the elec-
tric power system. The document is the outcome of task T2.1 titled “Modeling for cyber-physical
risk assessment”. The task was defined with two complementary modeling objectives. Firstly, to ad-
dress the question of cyber-physical dynamic equivalent models allowing to abstract away smaller
or neighbouring parts of a system while studying its behavior from a more global perspective. The
precise scope here was to investigate how one could leverage existing approaches that allow to ab-
stract away the physical behavior of the system sub-part in question, so as to also reflect their cyber-
physical behavior. The second objective was to extend the scope of the physical benchmarks deemed
relevant in task T1.3 so as to fit the needs of transmission grid cyber-physical risk assessment.
Chapters 2 and 3 relate to the first objective, namely the development of cyber-physical dynamic
equivalent models to represent the behavior of sub-parts of the electric power grid. The work reported
in both these chapters focuses specifically in the case of distribution grids. This has been identified
by the researchers working in task 2.1 as the most relevant use case for representing external sys-
tems in the context of transmission level cyber-physical risk assessment. First, chapter 2 reviews
and qualitatively assess different cyber-physical threats that may act on the distribution level of the
electric power grid. The point here is to identify cyber threats that may have a noticeable impact as
“seen” from the transmission grid. Then, chapter 3 details and demonstrates a chosen approach for
the derivation of a simpler equivalent model of a distribution grid, on the basis of a corresponding de-
tailed model. This approach could be used to develop alternative equivalent distribution grid models
under the threats identified in chapter 2.
Chapter 4 documents the outcome of the effort to extend the scope of the benchmark systems
5identified in Task 1.3, so as to fit the needs for cyber-physical risk assessment at the transmission
level. It has to be noted that, from the onset of this effort, it was decided not to restrict the scope to
the benchmarks identified in Task 1.3. The reason for this was the fact that the available description
of such benchmarks was too generic to effectively distinguish them from any other academic bench-
mark. It was therefore decided to attempt to develop a generic process to extend the scope of any
physical power grid benchmark with an inventory of the cyber infrastructure that allows monitoring
and controlling the transmission system.