Modeling the Behavior of Flow Regulating Devices in Water Distribution Systems Using Constrained Nonlinear Programming

Deuerlein, Jochen; Simpson, Angus R.; Dempe, Stephan

doi:10.1061/(asce)hy.1943-7900.0000108

Cited by 27 publications

(18 citation statements)

References 18 publications

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“…A mathematically consistent approach to model the behavior of these devices was proposed by Deuerlein et al . [] based on content and cocontent model theory. The algorithm reported in Giustolisi et al .…”

Section: Wdn Modeling Backgroundmentioning

confidence: 99%

“…Deuerlein et al . [] also presented a methodology for analyzing system reliability where a graph decomposition of the network [ Deuerlein et al ., ] was exploited to reduce the number of calls of pressure‐driven simulation.…”

Section: Introductionmentioning

confidence: 99%

“…Giustolisi et al [2008a] proposed the fraction of unsupplied demand and volume as reliability indicators for each node and for the whole network; unsupplied water was estimated by pressure-driven extended period simulation assuming normal functioning demand patters. Deuerlein et al [2009] also presented a methodology for analyzing system reliability where a graph decomposition of the network [Deuerlein et al, 2008] was exploited to reduce the number of calls of pressure-driven simulation.…”

Section: Introductionmentioning

confidence: 99%

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Assessing mechanical vulnerability in water distribution networks under multiple failures

Berardi

Ugarelli

Røstum

et al. 2014

Water Resources Research

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Understanding mechanical vulnerability of water distribution networks (WDN) is of direct relevance for water utilities since it entails two different purposes. On the one hand, it might support the identification of severe failure scenarios due to external causes (e.g., natural or intentional events) which result into the most critical consequences on WDN supply capacity. On the other hand, it aims at figure out the WDN portions which are more prone to be affected by asset disruptions. The complexity of such analysis stems from the number of possible scenarios with single and multiple simultaneous shutdowns of asset elements leading to modifications of network topology and insufficient water supply to customers. In this work, the search for the most disruptive combinations of multiple asset failure events is formulated and solved as a multiobjective optimization problem. The higher vulnerability failure scenarios are detected as those causing the lower supplied demand due to the lower number of simultaneous failures. The automatic detection of WDN topology, subsequent to the detachments of failed elements, is combined with pressuredriven analysis. The methodology is demonstrated on a real water distribution network. Results show that, besides the failures causing the detachment of reservoirs, tanks, or pumps, there are other different topological modifications which may cause severe WDN service disruptions. Such information is of direct relevance to support planning asset enhancement works and improve the preparedness to extreme events.

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Section: Wdn Modeling Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Assessing mechanical vulnerability in water distribution networks under multiple failures

Berardi

Ugarelli

Røstum

et al. 2014

Water Resources Research

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“…The equality constraints consist of the continuity equations of the demand nodes. More details on the formulation of the Content minimization as an equivalent problem for the calculation of the hydraulic steadystate can be found in Collins et al (1978), Todini and Pilati (1988) and Deuerlein et. al.…”

Section: Proposed Modifications To Epanetmentioning

confidence: 99%

Preprocessing of Water Distribution Systems to Assess Connectivity and Solvability in the Presence of Flow Control Devices

Deuerlein¹,

Simpson

Montalvo³

2012

World Environmental and Water Resources Congress 2012

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Although mathematical modeling of the hydraulics and water quality of drinking water distribution networks is widely used in network planning and management existing solvers sometimes deliver no results or even wrong results if the connectivity of the system is not correctly maintained. In this paper two major causes for deficient network connectivity are considered.In the first case, the network graph consists of several maximal connected components where some of them have no node with a fixed head source. Those deficient networks can result from errors in the reference data system (GIS) or during data transfer. In the second case, all the links and nodes of the network graph are connected. However, some links representing control devices have upper and/or lower bounds for the flows. Similar problems as in the first case can be observed if the topology of the network is reduced by removing links with active flow control devices from the graph resulting in a disconnected system. The problem is that the identification of control devices that are active (when an inequality constraint is fulfilled be equality) at a certain time step is not straight forward and depends on the actual hydraulic state of the distribution system.In this paper two preprocessing steps of the hydraulic steady-state or extended period simulations are proposed to check the solvability of the mathematical problem with respect to the flow constraints. In the first step, the connectivity of the system is analyzed and network parts without a fixed head source are identified. In the second step, a Linear Program (LP) is formulated that includes the nodal continuity conditions plus additional inequality constraints that refer to the operation of the flow controlling devices. The optimal objective value of the LP indicates if for the original problem either a) a solution exists, b) does not exist or c) exists but has redundant control constraints.

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“…Control devices (e.g. pressure regulating valves) make the constitutive equations for water distribution systems difficult to solve due to convergence problems (Rossman 2007;Deuerlein et al 2009;Kovalenko et al 2014;Elhay et al 2015). While Tanyimboh and colleagues (Tanyimboh et al 2003;Tanyimboh and Templeman 2010) included pumps and control devices, extended period simulation was not considered.…”

Section: Introductionmentioning

confidence: 99%

Investigation into the Pressure-Driven Extension of the EPANET Hydraulic Simulation Model for Water Distribution Systems

Seyoum

Tanyimboh

2016

Water Resour Manage

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Several hydraulic modelling approaches have been proposed previously to simulate pressure -deficient operating conditions in water distribution networks more realistically. EPANET-PDX is a pressure-driven extension of the EPANET 2 hydraulic simulation model that has an embedded logistic nodal head-flow function. The pressure-driven analysis algorithm in EPANET-PDX was investigated, to improve its performance under conditions of extremely low pressure. By integrating a line minimization procedure fully in the computational solution of the system of equations, the algorithm's consistency was improved by increasing its computational efficiency under conditions of extremely low pressure. The examples considered demonstrated that the pressure-driven analysis algorithm proposed is robust, computationally efficient, and the line minimization procedure is applied frequently. Overall, the results suggest that the algorithm is reliable. The formulation proposed is significantly faster than the previous model under conditions of extremely low pressure. The hydraulic and water quality modelling functionality of EPANET 2 was preserved. For the operating conditions with satisfactory pressure, where direct comparisons with EPANET 2 were possible, EPANET 2 was consistently faster.

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Modeling the Behavior of Flow Regulating Devices in Water Distribution Systems Using Constrained Nonlinear Programming

Cited by 27 publications

References 18 publications

Assessing mechanical vulnerability in water distribution networks under multiple failures

Assessing mechanical vulnerability in water distribution networks under multiple failures

Preprocessing of Water Distribution Systems to Assess Connectivity and Solvability in the Presence of Flow Control Devices

Investigation into the Pressure-Driven Extension of the EPANET Hydraulic Simulation Model for Water Distribution Systems

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