Modeling Interdependencies with Complex Network Theory in a Combined Electrical Power and ICT System

The extensive integration of information and communication technology (ICT) in the future electrical power system transforms the power system to a cyber physical system (CPS), making it a system-of-systems. This new system topology creates interdependent relationships between the cyber and the physical parts in the power system and introduces new possible vulnerabilities and risks which might lead to unwanted events such as outages and blackouts. For electrical power system operators, it is important to understand the new complexity of the system and how to address these new changes in order to ensure safe system operation and security of electricity supply. This paper focuses on the introduction of complex network theory as a method to discover and measure the importance of the system nodes, both electrical and ICT, in a combined electrical power distribution and communication network. There are two different methods used for measuring the importance, 1) betweenness centrality and 2) node attack method. The methods are evaluated through a case study and found suitable in capturing the important nodes in the combined electrical power and communication network.