RELIABILITY-ANALYSIS OF WATER-DISTRIBUTION SYSTEMS

Traditional network analysis (Hardy Cross, Newton-Raphson, or linear theory methods) presumes that the nodal demands are always satisfied in a water-distribution system (WDS) and determines the available heads. However, when a pump fails or a pipe breaks, the WDS may be unable to supply all nodal demands at required heads. Thus, the traditional network analysis does not correctly describe the partially failed WDS. In reliability analysis of WDSs, however, the nodal flows that would be available under deficient conditions should be evaluated and used. Therefore, an approach termed node flow analysis that determines the available nodal flows under deficient conditions by considering the nodal demands and heads, simultaneously, is presented for determining WDS reliability. The reliability is based on a node-reliability factor, volume-reliability factor, and network-reliability factor. Even though WDS reliability depends on several parameters, only the pipe break and pump failure conditions are considered. However, several loading patterns, including fire flow requirements, can be considered as illustrated by a hypothetical example.