A Novel Approach to Analyze the Isolation Valve System Based on the Complex Network Theory

Complex Network Theory (CNT) studies network models and centrality metrics to deal with reliability/vulnerability assessment in networked systems. Classic CNT analyses evaluate the impact of failure of single vertices/edge elements on system connectivity assuming that all vertices/nodes have the same relevance. In Water Distribution Networks (WDNs), the Isolation Valve System (IVS) plays a crucial role for system reliability because a pipe failure asks for valves shutdown to isolate that pipe, usually requiring the isolation of a larger network segment, having its intrinsic relevance. This circumstance makes classic connectivity analyses and metrics of CNT misleading in reliability assessment of WDN. This work proposes a novel approach to analyze IVS, which is based on the construction of the graph of segments and isolation valves generated by the IVS. The application of the recently proposed relevance-based (WDN-tailored) betweenness centrality to such graph is used to rank the importance of segments and isolation valves. Two WDNs of different sizes are used to demonstrate and discuss the strategy also from a practical perspective.