scholarly journals A MINLP Model for Optimal Localization of Pumps as Turbines in Water Distribution Systems Considering Power Generation Constraints

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1979 ◽  
Author(s):  
Khoa Dang Nguyen ◽  
Pham Duc Dai ◽  
Dong Quoc Vu ◽  
Bui Manh Cuong ◽  
Vu Phi Tuyen ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Mixed Integer ◽  
Nonlinear Program ◽  
Bound Constraints ◽  
Minimum Power ◽  
System Pressure ◽  
Minlp Model ◽  
Optimal Localization

Pressure reducing valves (PRVs) are commonly used for pressure control in water distribution systems (WDSs) by means of dissipating the pressure excess. The use of pumps as turbines (PATs) is an alternative and more favorable system since they not only control the system pressure to decrease water leakage, but also utilize the pressure excess to generate electrical energy. The optimal localization of PATs can be casted into a mixed-integer nonlinear program (MINLP) where binary variables are used to represent the presence of PATs on links. Most of the available MINLP models for optimal PAT localization adopted the optimization approaches for PRV localization without considering the bound constraints on flow rates and heads of PATs. As a result, such an optimization model may make PATs delivering a non-desired output. In this paper, we propose a new MINLP model for optimal PAT localization. Instead of using a constraint on the maximum number of PATs to be placed in a WDS, new constraints relating to the minimum power generated by PAT are introduced to find links having adequate flows and head drops for placing PATs. Moreover, constraints are used to restrict flows and heads of PATs to their feasible operating range, so that the problem can be efficiently solved. The proposed MINLP model is applied to the optimal localization of PATs for a WDS benchmark and a real-world WDS in Vietnam. The results demonstrate that the new MINLP model can efficiently identify optimal locations for PAT placement where the specified working range and minimum power generated by the PATs are ensured.

scholarly journals A new mathematical program with complementarity constraints for optimal localization of pressure reducing valves in water distribution systems

2021 ◽  
Vol 11 (9) ◽  
Author(s):  
Pham Duc Dai
Keyword(s):  
Stationary Point ◽  
Water Loss ◽  
Optimization Model ◽  
Distribution Systems ◽  
Water Distribution ◽  
Mathematical Program ◽  
Water Distribution Systems ◽  
Mixed Integer ◽  
Complementarity Constraints ◽  
Optimal Localization

AbstractWater loss reduction in water distribution systems (WDSs) is a challenging task for water utilities worldwide. One of the most reliable and cost-effective ways to reduce water loss is to properly regulate operational pressure of the system through optimizing pressure reducing valve (PRV) placements. This well-known engineering problem can be casted into a mixed-integer nonlinear program (MINLP) where binary variables are introduced to represent positions of PRVs. Many works in the literature applied heuristic algorithms to address the optimization problem. In this paper, at first, we proposed a new optimization model and reformulated it as the mathematical program with complementarity constraints (MPCCs). It is due to the fact that the stationary point of the MPCCs is likely to be trapped into bad local solutions, a soft heuristic method is then proposed to determine the MINLP local solution in each iteration before a stationary point of the MPCCs is reached. This method not only enhances the quality of MINLP solution, but also decreases computation time for solving the MPCCs. The newly formulated MPCCs is applied to determine optimal localization of PRVs for two WDS benchmarks and a real-world WDS in Vietnam. The results are compared with others in the literature demonstrating that using our new optimization model, better and more reliable MINLP solution can be found for large scale WDSs.

scholarly journals Optimal Resilience Enhancement of Water Distribution Systems

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2602 ◽  
Author(s):  
Imke-Sophie Lorenz ◽  
Peter Pelz
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Cost Benefit ◽  
Combinatorial Problem ◽  
Urban Transport ◽  
Main Line ◽  
Mixed Integer ◽  
Urban Structure ◽  
Daily Consumption

Water distribution systems (WDSs) as critical infrastructures are subject to demand peaks due to daily consumption fluctuations, as well as long term changes in the demand pattern due to increased urbanization. Resilient design of water distribution systems is of high relevance to water suppliers. The challenging combinatorial problem of high-quality and, at the same time, low-cost water supply can be assisted by cost-benefit optimization to enhance the resilience of existing main line WDSs, as shown in this paper. A Mixed Integer Linear Problem, based on a graph-theoretical resilience index, is implemented considering WDS topology. Utilizing parallel infrastructures, specifically those of the urban transport network and the water distribution network, makes allowances for physical constraints, in order to adjust the existing WDS and to enhance resilience. Therefore, decision-makers can be assisted in choosing the optimal adjustment of WDS depending on their investment budget. Furthermore, it can be observed that, for a specific urban structure, there is a convergence of resilience enhancement with higher costs. This cost-benefit optimization is conducted for a real-world main line WDS, considering also the limitations of computational expenses.

scholarly journals Optimal Pressure Management for Large-Scale Water Distribution Systems Using Smoothing Model

2020 ◽  
Vol 30.8 (147) ◽  
pp. 34-39
Author(s):  
Duc Dai Pham ◽  
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Large Scale ◽  
Water Distribution Systems ◽  
Smoothing Function ◽  
Nonlinear Program ◽  
Pressure Management ◽  
Program Problem ◽  
Comparison Results ◽  
Smooth Constraints

Optimal pressure management in water distribution systems (WDSs) is one of the most efficient approaches to control water leakage for water utilities worldwide. The optimal pressure management can be accomplished through regulating operations of pressure reducing valves (PRVs) to ensure that the excessive pressure in the WDS is minimized. This engineering task can be casted into a nonlinear program problem (NLP) with non-smooth constraints. Until now, the non-smooth constraints have been approximated by the smoothing function of Chen Harker-Kanzow-Smale (CHKS). In this paper, instead of using the CHKS function, we propose to apply the uniform smoothing function for formulation of the NLP. Numerical simulations using two smoothing functions will be carried out for optimal pressure managements of a benchmark WDS and a real-world WDS in Thainguyen City, in Vietnam. The comparison results reveal that the NLP formulated with the uniform smoothing function outperforms the existing NLP formulated with the CHKS in terms of optimal solution accuracy.

An Ontological Approach to Water Distribution Systems Management

WRPMD'99 ◽  
1999 ◽  
Author(s):  
P. Costa ◽  
A. Esposito ◽  
C. Gualtieri ◽  
D. Pianese ◽  
G. Pulci Doria ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Systems Management ◽  
Ontological Approach

Robust Estimation of Integrated Hydraulics and Parameters in Water Distribution Systems

2001 ◽  
Author(s):  
Mietek A. Brdys ◽  
Kazimierz Duzinkiewicz ◽  
Michal Grochowski ◽  
Tomasz Rutkowski
Keyword(s):  
Robust Estimation ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems
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