scholarly journals The Sensitivity of a Water Distribution System to Regional State Parameter Variations

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Philip R. Page
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
State Parameter ◽  
Reservoir Water ◽  
Flow Rates ◽  
Parameter Variations ◽  
Pipe Roughness ◽  
Minor Losses ◽  
First Time

The sensitivity of a pressurised water distribution system (WDS) to state parameter variations is studied. A novel local regional sensitivity analysis (LRSA) approach is introduced which applies the same change to a collection of parameters, called a region. For example, sensitivity to suburbs can be studied. General analytical (using algebraic methods) results are derived. They show how sensible conclusions arise from LRSA and state this dependence of the WDS on regions for the first time. For most cases, the WDS is 1.852–2 times more sensitive to pipe roughness coefficients than to pipe lengths. In most cases, when certain pipes do not have minor losses, the WDS is 4.871–5.333 times more sensitive to pipe diameters than to pipe lengths. Hence, the WDS is the most sensitive to pipe diameters, medium sensitive to pipe roughness coefficients, and least sensitive to pipe lengths. For most cases, when all reservoir and tank elevations (and heads) remain the same, changes of other elevations do not change flow rates and change the pressures in a simple additive way. In most cases, when all the reservoir water surface elevations are changed together, the flow rates remain unchanged, and the pressures change in a simple additive way.

Water distribution system model calibration under uncertainty environments

2010 ◽  
Vol 10 (1) ◽  
pp. 31-38 ◽  
Author(s):  
S. Takahashi ◽  
J. G. Saldarriaga ◽  
M. C. Vega ◽  
F. Hernández
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Solution Space ◽  
Programming Algorithm ◽  
Satisfactory Outcome ◽  
Manual Methods ◽  
Minor Losses ◽  
Maintenance Model ◽  
Direct Use

The calibration process of water distribution system models allows for accurate and reliable hydraulic analysis results. Thus, calibration is of utmost importance if adequate operation and maintenance model-based procedures are sought. However, in emerging economies, there is a series of factors that make it more difficult to construct accurate models, including very poor information management, unusually high leakages and the presence of a large number of illegal connections. While some of the model variables are assumed to be known under normal circumstances, these factors make it necessary to consider them for calibration as well. This paper presents a calibration methodology flexible enough to address such problems allowing the calibration of pipe diameter, roughness and minor losses, and nodal demands and leakages. A genetic algorithm was implemented as well as a constraint programming algorithm that makes direct use of hydraulic criteria to advance in the solution space. The methodology was tested on a real system in Colombia with a satisfactory outcome. The use of these techniques results in major reduction of calculation time and similar or superior results in comparison to manual methods.

Multi-objective optimisation of the operation of a water distribution network

2014 ◽  
Vol 64 (3) ◽  
pp. 235-249
Author(s):  
Michael Mulholland ◽  
M. Abderrazak Latifi ◽  
Andrew Purdon ◽  
Christopher Buckley ◽  
Christopher Brouckaert
Keyword(s):  
Genetic Algorithm ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Network ◽  
Reservoir Water ◽  
Minimum Interval ◽  
Pareto Fronts ◽  
The Cost ◽  
Near Optimality

The aim of the present paper was to move water through a reservoir network in such a way as to meet consumer demands and level constraints, minimise the cost of electricity, and minimise the loss of chlorine. This was to be achieved by choosing the switching intervals of reservoir inlet pumps and valves, at the same time complying with the allowed minimum interval size of each device. Switching combinations that threatened to exceed constraints were rejected heuristically. Flows were balanced by linear programming (LP). The genetic algorithm gave confidence in the near-optimality of its solutions, through the well-defined Pareto fronts between the competing objectives. The method was applied to a 16-reservoir water distribution system in Durban, South Africa. Comparison with an equivalent ‘dead-band’ control showed a 30% improvement in a weighted objective.

Calibration of Hydraulic Model in Rea-Life Water Distribution System

2012 ◽  
Vol 155-156 ◽  
pp. 285-290 ◽  
Author(s):  
Wei Wei Zhang ◽  
Guo Ping Yu ◽  
Miao Shun Bai
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Real Life ◽  
Hydraulic Model ◽  
Calibration Model ◽  
Loading Conditions ◽  
Head Losses ◽  
Real Coded Genetic Algorithm ◽  
Pipe Roughness

The most uncertain input parameters that often considered for calibration in water distribution system hydraulic model are pipe roughness coefficients and nodal demands. Both pipe roughness coefficients and nodal demands are considered to be calibrated in the calibration process, which works alternately. The calibration model was formulated as a constrained optimization problem. The entire head losses under different loading conditions are introduced in the objective function to guide the calibration direction, which can make consistent calibration effects on different loading conditions. The calibration model uses real-coded genetic algorithm along with a general network solver (EPANET 2.0) to adjust pipe roughness coefficients and nodal demands multipliers until the preset criteria are meet. The approach was applied in the calibration of a real-life water distribution system hydraulic model in China, which takes three loading conditions (max, min and average hour) into consider. The results show that the approach works well in achieving good calibration results, which match field observation in a reasonable level and meet engineering requirements.

Sign in / Sign up

Export Citation Format

Share Document