Improved Loop-Flow Method for Hydraulic Analysis of Water Distribution Systems

Different methods have been developed in the past to formulate and solve steady-state hydraulics of a water distribution system (WDS). The most widely used method nowadays is probably the global gradient algorithm (GGA). The loop-flow method (also known as the Q method) represents a viable alternative to GGA, especially when combined with suitably preprocessed network data. The main advantage of the Q method over the GGA is in the smaller number of unknowns to solve for, which is coming from the fact that real WDSs typically have far less loops than nodes. A new loop-flow-type method, relying on the novel triangulation based loops identification algorithm (TRIBAL) that was implemented in the corresponding new hydraulic solver (Q), is presented in this paper (TRIBAL-Q). The new method aims to exploit this advantage, while overcoming key drawbacks of existing Q methods. The performance of the TRIBAL-Q-based solver is compared with the GGA-based solver on four large real networks of different complexity and topology. The results obtained demonstrate that, despite requiring an increased number of iterations to converge, the TRIBAL-Q method-based solver is substantially computationally faster, has slightly better numerical stability, and is equally accurate in making predictions when compared with the GGA-based hydraulic solver.