In this talk, we present three results related to the assessment of the robustness of energy networks. The first result concerns cascading failures in power grids. It is known that cascading failures are one of the main reasons for blackouts in electric power transmission grids. The economic cost of such failures is in the order of tens of billion dollars annually. The loading level of power system is a key aspect to determine the amount of the damage caused by cascading failures. We will propose a model that quantifies the damage due to cascading failures in terms of spectral graph metrics, representing both the topology of the network as well as physical properties of the network. Experimental results applied to IEEE test systems demonstrate the applicability of these metrics. Next we look at the robustness of a communication network which depends on the proper functioning of an electricity network. The strategies involve selecting nodes of the communication network and removing their dependency to the electricity network. These selected nodes will be named autonomous nodes. We will model the electricity network realistically by not only looking at the topological structure, but also taking the essential characteristics of the power flow into account. The effect of cascading failures originating from the electrical grid, on the communication network is studied, where the coupling between those networks plays an important role. We have validated robustness optimisation strategies by averaging over many configurations of communication networks, applied to electricity network formed by the IEEE-118 bus test system. Our method is also tested on a real-world interdependent network: the high voltage electricity grid in Italy coupled with a communication network, inspired by the Italy blackout in 2003. Finally, we present a method to compute the all-terminal availability and the k-terminal availability of a real life gas distribution network with 20567 nodes and 20749 edges. The method first performs reductions on the network and afterwards uses a decomposition algorithm. The decomposition algorithm is exponential in the path-width of the graph. Some improvements and extensions of the method are suggested.
Robert Kooij has a background in mathematics: he received his PhD degree cum laude at Delft University of Technology in 1993. From 1997 until 2003, he was employed at KPN, the largest telecom operator in the Netherlands. Since 2003, he was employed at TNO, the Netherlands Organization of Applied Scientific Research. In 2011, he became Principal Scientist, conducting and managing research on Critical ICT Infrastructures. Since 2005, Robert is part-time affiliated with the Delft University of Technology, at the faculty of Electrical Engineering, Mathematics and Computer Science. Since 2010 he is a part-time full professor with the chair “Robustness of Complex Networks”. In 2016, Professor Kooij relocated to the TNO South-East Asia office in Singapore. As of April 2018, he is a principal research scientist at the SUTD, working on cybersecurity for critical infrastructures.
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