Jinliang Gao

Optimal placement of pressure monitors in water supply network with elitist genetic algorithm

Optimisation of pressure monitoring in a water distribution network is essential for water companies to provide safe and reliable water supply to customers. With analysis of pressure pertinence and its quantified criteria of nodes in a water supply network, a mathematical model has been established for optimal placement of pressure monitoring. The elitist genetic algorithm (GA) method was adopted for solving this model. The model is evaluated by solving an example network and improves the accuracy and feasibility of this optimal model.

Optimising pump system with constant and variable speed pumps: case study

Optimising pump scheduling is a complex problem, which involves a large space search, continuous and discrete variables, physical and operational constraints and also multi-objectives. In this paper, multi-objective evolutionary algorithms (MOEAs) combined with a repair mechanism are used to solve the optimal operation problem within water supply system. In this work two objectives are minimised: operation cost (energy cost + treatment cost) and maintenance cost, while one objective is maximised: service level of hydraulic. Decision variables are the settings of the pumps and speed ratio of variable-speed pumps at a time step of the total operational time horizon. A mixed coding methodology and a new crossover operator are developed according to the characteristics of decision variables. Three well-known MOEAS (NSGA-II, epsilon-MOEA and SPEA2) are implemented and compared. Practical application of this method shows that it can make efficient decision to support the operators.

Water distribution network real-time simulation based on SCADA system using OPC communication

Hydraulic simulation models of water distribution networks (WDN) are routinely used for operational investigations and network design purposes. However, their full potential is often never realized because in the majority of cases, they have been calibrated with data collected manually from the field during a single historic time period and reflects the network operational conditions that were prevalent at that time. They were then applied as part of a reactive investigation. An urban water distribution network real time simulation system based on SCADA system using OPC (object linking and Embedding(OLE) for Process control) communication was built in this paper. In order to make real-time simulation of water distribution network, the real-time data was collected every 15 minutes, the real time data were received and sent into water distribution network simulation model by OPC communication of SCADA system. The real-time data included total head of reservoir, flow rate, pressure, pump operation information. The real-time simulation system can give timely warning of changes for normal network operation, providing capacity to minimize customer impact and comparing the simulation results with the real-time data collected. The real time simulation system of urban water distribution network solved the problem of data input and user interaction compare to traditional network model. It offers a way for the development of intelligent water network.

Enhancing the Reliability and Security of Urban Water Infrastructures through Intelligent Monitoring, Assessment, and Optimization

Urban water infrastructure systems are large, complex network systems. In delivering water to end consumers they are required to meet increasingly stringent water quality standards as well as minimum flow and pressure criteria. At the same time, water utilities are expected to become more effective and to demonstrate sustainability in both operation and profit. Water supply companies are facing growing costs related to the energy needed to meet increasing demand for water, due to leakage and water loss caused by the aging and failure of infrastructure and also due to climate changes, increased population density, etc. They also have to deal with increasing uncertainty from a range of threats including natural hazards and humancaused threats, such as climate changes and biochemical contamination. This chapter will investigate intelligent monitoring, assessment and optimization techniques that can be applied in urban water infrastructures to improve the spatial and temporal resolution of operational data from water distribution networks and address the challenge of real-time monitoring and control in large-scale complex distributed environments. We will explore techniques that can comprehensively monitor a complex, highly dynamic environment and enhance the reliability and security of urban water infrastructures through intelligent monitoring, assessment and optimization.

Multi-objective optimization of water supply network rehabilitation

Water network rehabilitation is a complex problem, and many facets should be concerned in the solving process. It is a discrete variables, non-linear, multi-objective optimal problem. An optimization approach is discussed in this paper by transforming the hydraulic constraints into objective functions of optimization model of water supply network rehabilitation problem. The non-dominated sorting Genetic Algorithm-II (NSGA-II) was adopted to solve the altered multi-objective optimal problem. The introduction of NSGA-II for water supply network optimal rehabilitation problem results in solving the conflict between one fitness value of standard genetic algorithm (SGA) and multi-objectives of rehabilitation problem. Moreover, it benefits to control the uncertainties brought by using weighting coefficients or punish functions in conventional methods. In order to accelerate the convergence speed of population, this paper introduces the artificial inducement mutation (AIM). It not only improves the convergence speed, but also improves the rationality and feasibility of solutions.

The water distribution network digital management platform in Harbin, China

Water distribution network rehabilitation project is based on the digital analysis platform. The platform is built on the basis of microscope model in water distribution network. The water distribution network can be simulated under all kinds of scenarios, and the state-of-art can be shown in many ways by the digital analysis platform. It is very useful for the switch between the new and the old water sources, and for optimal control of water network. The digital analysis system for water distribution network has been successfully applied in the switch of water sources in a metropolis in north-eastern China. In conclusion, the digital platform is a powerful tool to realize the digital water distribution network. And it also provides effective guarantee for scientific control, operation, management and improvement of water distribution network.

Subatmospheric pressure protection for large diameter long distance pipeline system: A case study

Typical surge analysis of long distance pipelines involve pump power failure and startup at lift stations discharging into force mains. Utilities have several options for protecting pipeline systems from the effects of transients and surges. But how to select an effective surge protection strategy to design the system to withstand the stresses of transients is still a great challenge, especially for a high-lift, multiple peaks long distance system. This paper describes unique considerations that should be addressed when performing hydraulic transient analysis and recommending surge protection for water supply systems. Hydropneumatic tanks, surge tanks, vacuum breaker valves, surge-anticipator valves (SAV), surge relief valve (SRV), or both of them combined, and air valves will be discussed. Recent project examples and the effect of these new devices on surge protection in China will be presented.

Analysis of Water Supply Capacity under the Condition of Trenchless Rehabilitation Technology

The trenchless technology has been widely used in water pipeline recovering technology, in which various kinds of pipes are used. This paper discussed the appropriate supply hydraulic calculation method for respective pipes through analysis of flow pattern in the pipes. Then their respective water supply capacities are analyzed qualitatively and quantitatively, which can provide references for designers, managers, construction workers.

STUDY ON RESIDUAL CHLORINE CONTROL OF WATER DISTRIBUTION SYSTEMS WITH MULTIPLE WATER SOURCES

A best chlorine injection schedule for each source and booster station in a distribution system is studied and a multiple object optimal operation model of water distribution system(WDS) considering residual chlorine is also presented. The optimal scheduling of water distribution system is composed of two parts, the hydraulic and the water quality optimal control, and water quality optimal control is based on the hydraulic optimal control. As an important component of water quality optimal control, the residual chlorine control is selected as one of the objective functions of the optimal scheduling of water distribution system. A new multiple objects optimal operation model of WDSs is developed. The objective functions include minimum of residual chlorine and minimum costs of WDSs operation. The decision variables include the demand, pressure and residual chlorine at each water source, nodal demand, nodal pressure, and nodal residual chlorine. The hydraulic and the water quality model are solved by EPANET. The multiple objects optimal operation model of WDS is solved by the non-dominated sorting genetic algorithm (NSGA-II). Adaptive penalty functions are also applied in the process of model solved As a case study, the multiple objectives optimal operation model is applied in a large scale WDS. The WDS ’s total demand is about 1,320,000 m 3 /d, and is composed of 9 water plants, 32 water sources, and 468 wells. The result shows that the optimization of chlorine of each water source makes the distribution of nodal chlorine more reasonable and the concentration of nodal residual chlorine was reduced.

Research on Water Quality Comprehensive Evaluation Index for Water Supply Network Using SOM

A water quality comprehensive evaluation was taken for the water in water supply network. It was on the basis of water supply network microcosmic model. The water quality indicators, by which the state of water quality was expressed, were chosen as the input vector for the comprehensive evaluation model. The self-organizing feature map and k-means arithmetic were taken in the model. As a result, a comprehensive water quality evaluation method was proposed for the defects of single indicator grade evaluation. And the objective water quality evaluation model of water supply water network was taken. Compared with the single-evaluation indicators, SOM can take into account the single water quality monitoring data and the overall data, and reflect the water quality distributing in the water supply network objectively.