A flow-based method for identifying critical pipelines in complex natural gas supply systems

Natural gas supply systems are complex pipeline networks, whose features can cause severe consequences under unexpected scenarios. In this work, we present the research being performed to develop a method for efficiently measuring and locating pipelines which are critical to gas distribution. Graph theory, thermal-hydraulic simulation, optimization and network flow method are integrated to calculate the pipeline criticality with respect to the supply of gas. Graph theory is applied to model the supply-transmission-demand systems. A capacity model, superposed on the graph model, and a combination of thermal-hydraulic simulation and optimization is used to simulate the system operation under different scenarios and estimate the different supply performances of the pipelines. This allows to assess the criticality of the pipelines by the network flow method. For demonstration, the method is applied to a relatively complex gas pipeline network. The results of the application show that the method can provide analytical information useful to improve the system robustness and perform a more efficient and effective protection of the gas supply system.