Comparative Study of Reliability Assessment Approaches for Water Pipeline Networks

摘要

Water distribution systems (WDS) are crucial for communities' survival and economic prosperity around the world. The increasing scarcity of freshwater resources combined with deteriorating infrastructure distresses and growing number of main breaks is pushing water utilities to employ efficient reliability assessment approaches to monitor and control supply availability. Reliability evaluation of water distribution systems is a complex task as it requires both clear definition and careful computation of WDS performance in various failure states. This paper presents a comparison of two reliability measures, namely contingency reliability (CR) and minimum cut-set (MC) reliability, and demonstrates them on a benchmark WDS. This paper leverages a recently proposed non-iterative pressure driven demand (PDD) simulation approach in conjunction with EPANET hydraulic solver for the assessment of WDS performance in failure states. Both the reliability measures are separately used as objectives along with cost to design the benchmark WDS using a multi-objective evolutionary optimization algorithm. The resulting solutions from each reliability measure are comparatively assessed. Minimum cut-set was found to have performed better than CR in the comparative assessment. Both approaches were found to have certain limitations. A hybrid minimum cut-set approach in which a threshold demand-dissatisfaction that would distinguish concerning system failures from others may be more useful. Similarly, a modified contingency reliability approach that is suitable for all types of water distribution system configurations and sizes may be more useful. The identification of most competent reliability method will support optimal design and rehabilitation decision making for water distribution systems in a computationally efficient manner.