Functionality analysis of an urban water supply network after strong earthquakes

An urban water supply network(WSN)is a crucial lifeline system that helps to maintain the normal functioning of modern society.However,the hydraulic analysis of a significantly damaged WSN that suffers from pipe breaks or leaks remains challenging.In this paper,a probability-based framework is proposed to assess the functionality of WSNs in the aftermath of powerful earthquakes.The serviceability of the WSN is quantified by using a comprehensive index that considers nodal water flow and nodal pressure.This index includes a coefficient that reflects the relative importance of these two parameters.The demand reduction(DR)method,which reduces the water flow of nodes while preventing the negative pressure of nodes,is proposed.The difference between the negative pressure elimination(NPE)method and the DR method is discussed by using the example of a WSN in a medium-sized city in China.The functionality values of the WSN are 0.76 and 0.99 when nodal pressure and nodal demands are used respectively as the index of system serviceability at an intensity level that would pertain to an earthquake considered to occur at a maximum level.When the intensity of ground motion is as high as 0.4 g,the DR method requires fewer samples than the NPE method to obtain accurate results.The NPE method eliminates most of the pipes,which may be unrealistic.

Seismic reliability analysis of urban water distribution network

An approach to analyze the seismic reliability of water distribution networks by combining a hydraulic analysis with a first-order reliability method （FORM）, is proposed in this paper. The hydraulic analysis method for normal conditions is modified to accommodate the special conditions necessary to perform a seismic hydraulic analysis. In order to calculate the leakage area and leaking flow of the pipelines in the hydraulic analysis method, a new leakage model established from the seismic response analysis of buried pipelines is presented. To validate the proposed approach, a network with 17 nodes and 24 pipelines is investigated in detail. The approach is also applied to an actual project consisting of 463 nodes and 767 pipelines. The results show that the proposed approach achieves satisfactory results in analyzing the seismic reliability of large-scale water distribution networks.

Optimal Dispatching of Large-scale Water Supply System

This paper deals with the use of optimal control techniques in large-scale water distribution networks. According to the network characteristics and actual state of the water supply system in China, the implicit model, which may be solved by utilizing the hierarchical optimization method, is established. In special, based on the analyses of the water supply system containing variable-speed pumps, a software tool has been developed successfully. The application of this model to the city of Shenyang (China) is compared to experiential strategy. The results of this study show that the developed model is a very promising optimization method to control the large-scale water supply systems.

Improved Water Network Macroscopic Model Utilising Auto-Control Adjusting Valve by PLS

In order to overcome the low precision and weak applicability problems of the current municipal water network state simulation model, the water network structure is studied. Since the telemetry system has been applied increasingly in the water network, and in order to reflect the network operational condition more accurately, a new water network macroscopic model is developed by taking the auto-control adjusting valve opening state into consideration. Then for highly correlated or collinear independent variables in the model, the partial least squares (PLS) regression method provides a model solution which can distinguish between the system information and the noisy data. Finally, a hypothetical water network is introduced for validating the model. The simulation results show that the relative error is less than 5.2%, indicating that the model is efficient and feasible, and has better generalization performance.

Joint optimization scheduling for water conservancy projects incomplex river networks

In this study, we simulated water flow in a water conservancy project consisting of various hydraulic structures, such as sluices, pumping stations, hydropower stations, ship locks, and culverts, and developed a multi-period and multi-variable joint optimization scheduling model for flood control, drainage, and irrigation. In this model, the number of sluice holes, pump units, and hydropower station units to be opened were used as decision variables, and different optimization objectives and constraints were considered. This model was solved with improved genetic algorithms and verified using the Huaian Water Conservancy Project as an example. The results show that the use of the joint optimization scheduling led to a 10% increase in the power generation capacity and a 15% reduction in the total energy consumption. The change in the water level was reduced by 0.25 m upstream of the Yundong Sluice, and by 50% downstream of pumping stations No. 1, No. 2, and No. 4. It is clear that the joint optimization scheduling proposed in this study can effectively improve power generation capacity of the project, minimize operating costs and energy consumption, and enable more stable operation of various hydraulic structures. The results may provide references for the management of water conservancy projects in complex river networks.

考虑水质因素的供水管网抗震韧性评估

城市基础设施系统抗震韧性分析模型是评估城市防震减灾能力并指导震后恢复工作的重要依据。提出了耦合水力与水质模拟的供水管网抗震韧性评估模型。根据管道地震易损性模型和Monte Carlo模拟生成管网地震破坏场景,并采用动态重要度方法模拟管网震后修复过程。通过管网中余氯浓度的降低表示地震破坏对管网水质的负面影响,震后管网余氯浓度的变化取决于管道破坏引起的供水路径和水量的变化。采用震后余氯浓度未下降的用户节点供水量,作为管网系统水质性能评估指标。所提出的模型应用于2个不同布局的Benchmark案例管网。研究结果表明:管道破损处的水量漏失导致其上游管道的水流量增加、余氯浓度增大,下游管道的供水路径延长、余氯浓度减小。管网的水质韧性值往往低于水力韧性值,水力和水质韧性相对差异程度受到管网布局和运行规则的影响,文中案例管网水质和水力指标计算的抗震韧性损失指标的相对差异在17%~286%之间;运行规则复杂且含有调节水箱的管网,其水力和水质韧性的差异较大。

基于一元线性回归模型的供水网络中水表读数虚高问题研究

为了定量研究供水网络中总表漏水程度和分表读数虚高程度,根据水量平衡分析法的原理,结合大数据分析技术,建立了一元线性回归方程,回归常数代表总表漏水量程度,回归系数代表分表读数虚高程度。通过针对2021年某高校供水管网的实证研究表明,总表日均漏水量为15.5958吨,分表读数虚高率为1.07%。该方法对供水管网漏损率的精准评估等问题的解决提供了新的思路和方法。

水力条件对供水管网微生物影响研究进展

供水管网内微生物异常增殖会降低水质,威胁用户用水安全,因此控制管网微生物是保障饮用水安全的重要措施。管网微生物的生长和去除受到管网水力条件的影响,且在管网不同位置处所受影响程度不同。综述了水力停留时间和流速对管网微生物生长的影响,以及水力冲刷对生物膜的去除作用,发现水力停留时间和流速对微生物量与群落结构有显著影响,水力冲刷对不同条件下形成的管壁生物膜去除效果不同,研究结果可为供水管网微生物控制的研究和应用提供重要参考。

基于串级LSTM深度学习模型的二次供水余氯预测方法

伴随着城市高层住宅的增多,住宅区内二次供水泵房数量迅速增加。由于二次供水水箱位于城市供水系统末端,水质安全引起社会广泛关注。为提升水箱水质,一些泵房引入自动补氯装置,然而传统自动控制方法在应对二次供水系统中长时间延迟和非线性特性的补氯系统时存在局限性,仅能在线监测水箱余氯水平,过多的余氯可能对人体健康有害,因此,确保自动补氯系统安全运行成为亟待解决的问题。研究提出基于串级LSTM深度学习的神经网络模型,用于分析水箱余氯数据、准确预测水箱出水余氯浓度,并制定相应监测和控制策略。试验验证和实际应用结果表明,该深度学习模型能有效智能预测水箱余氯,为自动补氯系统提供重要的智能控制手段,具有实用意义。

深圳市典型小区供水水力水质模型建设与应用

文章选择深圳市两个经过优质饮用水改造和远传水表安装的典型居民小区,通过小区供水管网与爬墙立管的拓扑绘制、用户水表挂接、用水量分配和用水模式设置、监测和校核数据设置、二供水泵曲线提取、边界条件设置等关键问题研究,建立起楼宇水力和水质模型。经过多点、连续和多时段实测数据的比对校核,使模型达到较好的精度。在此基础上,开展小区用户风险模拟、快速风险评估、二供运行优化等应用。该研究为探索小区模型的建设和应用提供了基础,初步形成小区水力、水质特征研究和评估的理论与方法。

基于供水管网水力模型的市政管网消防供水能力研究

为提高城市消防安全水平和火场救援的效率和质量,基于供水管网水力模型,对市政管网消防供水能力进行研究,利用算法分析计算应急状态下满足消防取水需求的市政管网最大消防给水量,得出市政给水设施在火灾条件下的实际给水能力。填补城市消防给水设施管理部门和消防实战应用单位之间的真空地带,解决各信息之间的“信息断层”和应用系统之间的“信息孤岛”问题,充分发挥城市消防给水设施效能,保障消防安全。

基于模型驱动的供水自适应调度应用研究

随着供水企业精细化管理需求的日益增长,对供水调度的要求也随之提升。研究了基于水力模型的供水管网自适应优化调度方法,通过建立水力模型及水量预测模型,基于遗传退火模拟搜索算法,建立了优化调度的数学模型,同时结合工况聚类分析,大大降低搜索算法运算量,提升优化调度方案生成效率,实现供水管网自适应调度系统。此外,该系统与厂站控制系统对接完成自动调度控制,实现了系统自动厂站、管网优化调度。基于深圳市FY水司实际生产工况,实现区域内供水压力平稳,整体配电能耗下降约3%,系统调度方案生成时间不超过40 s,调度指令自动执行时间优于30 s,运行效果显著,有效提升了调度效率,实现供水调度的提质增效。

山地城市给水管网压力分区策略研究与应用

山地丘陵地区的城市供水管网,在满足用户用水需求的同时,可能面临局部区域压力过高的问题,而高压会导致供水管网的漏损量增加。依托某山地城市供水管网水力模型,提出“界限清晰、压力均衡、水头递减、局部加压”的分区分压策略,对供水管网进行压力分区划分,配合基于时间的阀后压力控制方式进行分区控压,相比于传统的阀后压力控制方式,能够更好地减少管网漏失水量,均衡管网压力,为山地城市供水系统的运行提供了重要参考。

基于EPANET水力模型的隧道消防供水管网模拟

随着城市发展,旧城区交通流量不断增加,下穿隧道成为缓解交通压力的一种有效方法。位于我国西南地区的旧城区因地形高差起伏较大、现状市政供水管道压力分布不均匀,导致常规计算难以判断隧道内各点的消防供水压力。文章以四川省宜宾市某隧道工程为例,采用EPANET水力模型对隧道消防供水管网进行模拟研究,分析3种消防水源不同组合工况下消火栓系统的运行压力。研究表明,消防水源采用对角线的布置方式更为合理,使得管网运行压力更均匀,消防供水也更加安全。通过EPANET进行水力模拟,可更加准确、直观地判断不同水源工况下管网系统的运行状况,为复杂型隧道消防系统设计提供理论依据。

居住区供水系统压力调控与水龄优化模拟研究

为进一步改善居住区供水品质、降低供水管网运行能耗,通过对上海某老旧小区的供水管网进行模拟,根据现状供水管网布置,针对水龄优化提出管径优化和管路优化2个方案,比较了水龄、水压、水质等水力情况。在管路优化的基础上进一步探讨了树状管网和环状管网对水质的影响。针对能耗较高的问题提出对居住区泵站进行优化运行,在现有基础上对比了降低水压恒压运行与分时段设置压力运行的水压稳定性与能耗高低,确定了最适合居住区泵站的运行方式。根据模拟结果,最终确定水龄优化采用变换管径的方式,这可以提升供水管网的水质和稳定性;泵站采用降压恒压运行的方式,在降低操作难度的同时,可以降低能耗,实现碳减排的目标。

基于AHP法及熵权法采用物元可拓模型在城乡供水管网项目后评价中的应用

随着农村地区城镇化的不断加深,居民对市政供水的需求日益增长,供水管网作为供水系统的主要组成部分,其建设和管理对居民的生活质量和城镇化进程起着重要的作用。近年来,随着大量城乡供水管网项目建设完成并投入使用,当前面临的一个重要问题是如何科学、客观地评价这些项目的实施效果,是否达到了预期目标。文章在研究了多种评价方法后,结合城乡供水管网项目的特点,最终确定采用物元可拓模型进行分析评价,其中指标权重通过AHP(层次分析法)确定,采用熵权法进行修正。通过该模型的应用,可对城乡供水管网项目进行有效评价,为企业今后的决策提供依据。

基于模型融合的供水管网渗漏预测研究

供水管网泄漏问题对水资源造成了严重浪费和污染。通过利用华中某企业的管网GIS数据库建立数据集,在传统分类模型中分析学习曲线和可靠性曲线,筛选出随机森林(RF)、逻辑回归(LR)和BP神经网络(BP)模型,并对其进行优化。最后,为克服单一预测模型的不足,引入了基于堆叠法(Stacking)和投票法(Voting)的融合模型。在融合模型中,将这三种模型作为基础模型,LR作为元模型。通过扩大模型的宽度,成功提高了模型的性能。实验结果表明,融合模型在测试集中预测供水管网漏水的准确率达到94.9%,AUC值为0.970。融合模型的预测能力明显优于任何仅使用单一特征构建的分类器,并具备良好的泛化能力和鲁棒性。

基于Model Online给水管网水力模型的分析与应用

为了更好地模拟和优化西南H镇城乡供水管网的设计,应用Model Online给水管网平差软件,综合考虑供水安全性与经济性对管网进行优化和模拟,得出最佳供水效果,以指导设计施工,为供水技术进入互联网时代探寻新的道路。

Hydraulic model for multi-sources reclaimed water pipe network based on EPANET and its applications in Beijing, China

Water shortage is one of the major water related problems for many cities in the world.The planning for utilization of reclaimed water has been or would be drafted in these cities.For using the reclaimed water soundly,Beijing planned to build a large scale reclaimed water pipe networks with multi-sources.In order to support the plan,the integrated hydraulic model of planning pipe network was developed based on EPANET supported by geographic information system(GIS).The complicated pipe network was divided into four weak conjunction subzones according to the distribution of reclaimed water plants and the elevation.It could provide a better solution for the problem of overhigh pressure in several regions of the network.Through the scenarios analy-sis in different subzones,some of the initial diameter of pipes in the network was adjusted.At last the pipe network planning scheme of reclaimed water was proposed.The proposed planning scheme could reach the balances between reclaimed water requirements and reclaimed water supplies,and provided a scientific basis for the reclaimed water utilization in Beijing.Now the scheme had been adopted by Beijing municipal government.

Predictive Zone Control of Pressure Management for Water Supply Network Systems

In this paper we address the problem of pressure management in water supply system （WSS） network. The model-based predictive control （MPC） strategies have some important features to deal with WSS. By hydraulic analysis of WSS, the predictive model is derived from the dynamic model and static model of WSS. Through WSS, the consumers＇ demands are required to be met at all times according to some operational constraints that must be satisfied. The constraints of flow through actuators, the water level of reservoirs and the consumer areas＇ pressure demand are determined by a specific system. In this work, we develop a constrained MPC controller that considers the zone control of the pressure outputs and incorporates steady state economic targets in the control cost function. The designed management strategies are applied to a case study and simulation results, covering different aspects, are provided. The output nodal pressure can be controlled in the desired zone by optimal scheduling the actuators of the WSS. If the variation range of reservoir＇s water level is broader, the rate of flow through the actuators is gentle, and vice versa.