Functionality assessment of natural gas distribution networks in post-earthquake scenarios with widespread component failures

Urban natural gas distribution networks are critical infrastructure systems that provide essential energy services to residential, industrial, and commercial sectors. However, these networks are highly vulnerable to earthquake-induced damage, leading to significant functionality loss and risks such as fires and explosions. To evaluate the functional status of natural gas pipeline networks under post-earthquake conditions, it is essential to develop a robust evaluation model capable of addressing large-scale component damage. This study proposes a natural gas pipeline network functionality assessment methodology that integrates islanding analysis to identify interconnected sub-networks, pressure-dependent demand modeling for user nodes, and a dual-control mechanism for gas source nodes to improve the accuracy of hydraulic calculations under accident conditions. Compared to traditional methods, the proposed approach provides a more accurate representation of natural gas pipeline network behavior under partial gas supply conditions. Validation on a representative natural gas pipeline network demonstrates its effectiveness in identifying and quantifying functional losses during extensive component failures. Comparative analysis reveals that traditional methods tend to overestimate network functionality under severe damage conditions, underscoring the advantages of the proposed approach. These findings confirm the methodology's suitability for evaluating functionality in scenarios of severe disruption.