Monitoring, Management and Control of Water Distribution Networks
Event details
| Date | 11.11.2016 |
| Hour | 10:15 › 11:15 |
| Speaker |
Prof. Shankar Narasimhan, Indian Institute of Technology Madras
Bio: Career Profile
2000 onwards Professor IIT Madras, Chennai 1996 - 2000 Associate Professor IIT Madras, Chennai 1994 - 1996 Associate Professor IIT Kanpur, Kanpur 1988 - 1994 Assistant Professor IIT Kanpur, Kanpur 1987 - 1988 Post-Doctoral Fellow Northwestern University, Evanston, USA Academic Profile Ph.D. (1987)Northwestern University Evanston, USA. M.S. (1984)Northwestern University Evanston, USA. B.Tech. (1982)IIT Madras Chennai, India |
| Location | |
| Category | Conferences - Seminars |
Water distribution networks (WDNs) are large scale, complex systems used for supplying potable water to consumers. The WDN infrastructure is typically designed to last more than 50 years. However, these systems are poorly instrumented and, hence, are neither maintained properly nor operated efficiently. In this talk, three problems of importance in monitoring and efficient operation of WDNs will be discussed which can take advantage of increased instrumentation/automation of these networks. The first problem we discuss is the identification of leaks in WDNs. In India it is estimated that more than 40% of the water supplied is lost through leaks. In order to rehabilitate the system, the leaking pipes have to be identified and either repaired or replaced. The limited number of instruments available in a network is insufficient for this purpose. We present an off-line technique for leak detection in WDNs using additional flow measurements. Since the pipes are buried underground, it is required to minimize the number of locations where additional flow measurements have to be made. A multi-stage graph partitioning approach is used to determine the location of flow measurements, with the objective of minimizing the number of measurements made. The graph partitioning problem can be formulated as a multi-objective integer linear programming (ILP). We show that a modified spectral bisection method can be used to derive an approximate solution for large scale networks. The proposed methods are tested on large scale benchmark networks, and the results indicate that on flows in less than 3% of the pipes on an average need to be measured to identify the leaky pipe or joint.
The second problem we discuss is the optimal operation of water networks to minimize energy required to meet the demands of consumers. Most WDNs in India are operated intermittently and are equipped with storage reservoirs both within the network (OHTs) as well as at consumer ends. The sequence in which the OHTs are filled has a significant impact on the time and energy required. The system we consider consists of pumps delivering water to different reservoirs in a network, with each reservoir catering to a time varying demand. Pumps and ON/OFF valves are used as manipulated variables to control the flow rate and delivery pressure. The decision variables are the number of pumps to be turned on and the state of the valves in the network over a given horizon and the objective is to minimize energy consumption while meeting the time varying demand. Given the nonlinear nature of the pump operating curve and the hydraulics, the resulting problem is a mixed integer nonlinear program (MINLP). Our proposed solution procedure decomposes this problem into a series of linear and integer sub-problems that can be solved efficiently. Application of these ideas to distribution networks reveals the potential for significant savings in energy or improvement in supply. Implementation of the proposed solution requires OHTs to be fitted with level sensors and installation of automatic ON/OFF valves at inlet to the OHTs
The third problem we discuss is concerned with the safety of WDNs. WDNs are considered as vulnerable assets that can be attacked by terrorists by introduction of toxic chemical or biological agents into the networks through accessible sources nodes in the network. Online sensors can be located at suitable locations in the WDN to detect whether a contaminant has been introduced and to identify the source of contamination. Furthermore, ON/OFF valves can be located in the WDN to prevent the spread of contaminant that may have been introduced. We propose solution techniques based on graph theoretic concepts which determine the optimal location of sensor and actuators to minimize the number of sensors and actuators deployed.
The second problem we discuss is the optimal operation of water networks to minimize energy required to meet the demands of consumers. Most WDNs in India are operated intermittently and are equipped with storage reservoirs both within the network (OHTs) as well as at consumer ends. The sequence in which the OHTs are filled has a significant impact on the time and energy required. The system we consider consists of pumps delivering water to different reservoirs in a network, with each reservoir catering to a time varying demand. Pumps and ON/OFF valves are used as manipulated variables to control the flow rate and delivery pressure. The decision variables are the number of pumps to be turned on and the state of the valves in the network over a given horizon and the objective is to minimize energy consumption while meeting the time varying demand. Given the nonlinear nature of the pump operating curve and the hydraulics, the resulting problem is a mixed integer nonlinear program (MINLP). Our proposed solution procedure decomposes this problem into a series of linear and integer sub-problems that can be solved efficiently. Application of these ideas to distribution networks reveals the potential for significant savings in energy or improvement in supply. Implementation of the proposed solution requires OHTs to be fitted with level sensors and installation of automatic ON/OFF valves at inlet to the OHTs
The third problem we discuss is concerned with the safety of WDNs. WDNs are considered as vulnerable assets that can be attacked by terrorists by introduction of toxic chemical or biological agents into the networks through accessible sources nodes in the network. Online sensors can be located at suitable locations in the WDN to detect whether a contaminant has been introduced and to identify the source of contamination. Furthermore, ON/OFF valves can be located in the WDN to prevent the spread of contaminant that may have been introduced. We propose solution techniques based on graph theoretic concepts which determine the optimal location of sensor and actuators to minimize the number of sensors and actuators deployed.
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