基于漏失定位的压力监测点优化布置方法

漏失定位模型是基于管网中压力监测点的压力变化来确定漏失的位置的模型,其定位准确度与供水管网中压力监测点的数量和位置密切相关。为此,基于压力驱动节点流量(PDD)漏失定位模型构建阈值求解模型,通过阈值构建压降变化矩阵,筛选出灵敏度高的节点,最后得到能兼顾定位模型准确度与压力监测成本的监测点优化布置方案。这对提高漏失定位模型定位准确度和漏损点检出效率具有重要意义。     

多能源站协同运行管网水力与热力模型及计算

该文改进传统管网水力模型,给出以节点压力表示的回路压力守恒方程,使水力模型只存在节点压力与节点位置信息,减少了模型求解的计算量。同时,结合管道热力传输方程以及两种类型节点温度平衡方程建立了管网热力模型。根据建立的水力模型和热力模型,设计了一款管网仿真计算软件,对一个规则的管网算例进行水力和热力参数计算,并搭建相应的实验装置对计算结果进行实验验证。结果表明,对比实验结果与仿真结果,水力参数的误差均不超过5%,从而验证了模型的正确性。最后在此基础上,对上海某区域实际的供能管网进行了设计工况下水力与热力的计算分析。     

基于改进灰狼优化算法的供水管网压力漏失调控优化研究

针对城市配水系统漏失控制的技术难题，以北方某城市CY区的大中型管网为研究对象，综合分析管网中各节点、管道、泵站及减压阀的水力特性，提出了阀门泵站一体的压力控制模型，以优化管网冗余压力和降低管网漏损率为目标，利用夜间最小流量法进行管网漏失量的分析计算。针对初代灰狼优化算法存在的种群多样性不足和容易陷入局部收敛的缺陷，调整了线性收敛因子的计算并对三只引导狼的权重进行自适应分配，同时引入基于维度学习的狩猎搜索策略对其进行改进，进而将其运用到实际工程的寻优计算中，得出减压阀和变速泵的最优调控方案。通过选取典型时段进行管网工况运行分析，结果证明提出的方案对于降低冗余压力和控制漏失具有显著作用。     

基于非恒定摩阻的管道泄漏数值模拟

输水管道的泄漏事故时有发生,而传统恒定摩阻模型无法精细描述泄漏时瞬变水击压力波的畸变和衰减过程,对管道泄漏检测非常不利。基于此,该文建立了考虑非恒定摩阻的管道瞬变流模型,对比了有无泄漏时非恒定摩阻对瞬变流动规律的影响,并对不同泄漏量和不同泄漏位置时管道泄漏的流量、压力参数变化进行了研究,为瞬变泄漏检测提供了理论指导和支持。模拟结果表明,非恒定摩阻不仅会加快水击压力波的衰减,也会引起相位的改变;泄漏点的存在会引起压力信号产生畸变,且畸变程度随泄漏流量和泄漏位置的变化有所不同。     

基于神经网络的管网漏失定位实例研究

为了在复杂且不直观的供水管网中快速实时定位漏点,以某城市区域管网为对象,在其上游、中游和下游各选取3条没有经过训练的管道,进行不同损坏程度的漏损模拟,利用BP神经网络可以逼近任意的非线性映射特点,将模拟数据作为训练样本训练神经网络,建立漏损点位置与测压点压力之间的非线性关系,构建基于BP神经网络的实时漏点定位模型。结果表明,模型预测的漏点位置横纵坐标的平均相对误差分别为4.16%和1.40%,预测的漏点偏移距离最小为6 m。当漏损面积比为0.01时,泄漏流量只有1 L/s,完全可以达到快速定位。此研究成果对实际管网的应用提供了理论基础和技术支持。     

给水管网漏失预测模型的研究

给水管网无论采用何种管材 ,随着时间的推移都会不可避免地发生漏失。根据实际给水管网的漏失数据 ,采用时间序列分析方法建立了给水管网漏失预测的线性指数平滑模型和二次曲线指数平滑模型。通过精度分析和比较 ,发现二次曲线指数平滑模型预测精度高于线性指数平滑模型 ,能更好地反映给水管网漏失频率随时间非线性增加的变化趋势。     

城市供水管网水量漏失监测机制研究

结合输配水管网平差模型,分析了节点水量漏失对管网节点压力的影响,同时利用聚类分析原理提出了一种旨在反映城市供水管网水量漏失点的方法,从而对管网漏水事故进行有效的监控。通过实例验证了方法的有效性和适用性。     

基于高维多目标优化的供水管网背景漏失控制优化模型

针对城市供水管网普遍存在的背景漏失问题,提出了控制背景漏失的高维多目标优化模型。介绍了同时考虑成本、背景漏失量、可靠性和水质指标的高维漏控模型,以及求解该模型的优化算法。结果表明:相比于只考虑成本和背景漏失量的低维多目标优化模型,高维模型有助于揭示成本、漏失量、可靠性和管网水质4个目标之间复杂的权衡关系。盲目降低漏失量会给管网可靠性和水质状况带来不利影响。该方法能为决策者提供更全面的分析结果,从而制定综合效益更优的背景漏失控制方案。     

基于WaterGEMS的供水管网建模及爆管分析研究

利用WaterGEMS建模软件及某市高新区自来水公司收集到相关数据,研究分析城市供水管网爆管事故,利用黄金分割法研究漏失水量,通过建模与计算机技术相结合进行动态分析,比较建立管网微观模型能够较好预测出供水管网发生爆管事故位置及漏失水量。     

给水管网实时故障诊断的支持向量机模型

为实时诊断给水管网故障,提出了一种基于支持向量机(SVM)的宏观关系模型,用以建立实时监测故障前后给水管网3个节点的水压变化与管网中其他所有未监测节点水压变化的非线性关系,通过对水压变化和等值线分析,可以快速和准确地诊断出故障位置和故障程度.最后,运用给水管网局部破坏状态下水力分析的算法求解一个小型给水管网.     

An Accurate Leakage Localization Method for Water Supply Network Based on Deep Learning Network

In the water supply network, leakage of pipes will cause water loss and increase the risk of environmental pollution. For water supply systems, identifying the leak point can improve the efficiency of pipeline leak repair. Most existing leak location methods can only locate the leak point approximately at the node or pipe section of the pipe network but cannot locate the specific location of the pipe section. This paper presents a framework for accurate water supply network leakage location based on Residual Network (ResNet). This study proposes a leak localization idea with a parallel classification and regression process that enables the framework to pinpoint the exact position of leak points in the pipeline. Furthermore, a multi-supervision mechanism is designed in the regression process to speed up the model’s convergence. For a pipe network containing 40 pipes, the positioning accuracy of the pipe section is 0.94, and the MSE of the specific location of the leakage point is 0.000435. For the pipe network containing 117 pipes, the positioning accuracy of the pipe section is 0.91. The MSE of the specific location of the leakage point is 0.0009177. Experiments confirm the robustness and applicability of the framework.

     

A Multiscale Approach to Leak Detection and Localization in Water Pipeline Network

Leak detection and localization in water pipeline networks is of paramount importance to industry, especially in regions where water is scarce. In this paper, we present a novel multi-modal and multi-scale approach for leak detection and localization in water pipeline networks, in which pressure measurements at various points on the network are used to localize the pipe segment in which the leak is occurring, and then the vibration sensors are used to localize the leak within this segment. In some situations where the complete pipeline model is not available, pressure data alone may not be effective in localizing the leak. However, in such a situation, by supplementing pressure data with vibration data, the leak can be localized, as these additional data are easier to acquire at arbitrary points, since vibration sensors are non-invasive. In order to validate the effectiveness of the approach that needs both pressure and vibration data, we simulate the pipeline model using EPANET that includes models for flow and pressure at various points on the pipeline, then integrate the vibration model with it in MATLAB, since EPNAET does not include models for vibration measurements. A case study of a pipeline network is considered, and the proposed scheme is used to detect and localize the leak. Extensive simulation results show the effectiveness of the proposed scheme in providing accurate leak detection and localization.     

Local and Global Leak Laws

The relationship between the functioning conditions of pipe systems and the leakage, or leak law, can be used at two different scales. At a local scale, i.e. for a single leak, it is derived from the classical orifice equation and, basing on experimental data, is modified to take into account all the relevant parameters it depends on (e.g., leak shape, pipe material and thickness, …). At a global scale, for a whole district or a part of a pressurized pipe system with several leaks, the same relationship is often used, basing on the assumption that the combination of local leak laws produces a similar global leak law. In this paper the effects of the spatial variation of the leak law parameters at the local scale on the leak law at a global scale are analyzed. Two leak laws derived from the orifice equation, the power law and the linear law, are considered. Results suggest that the global leak law exponent is larger than the corresponding mean local leak law exponent since it takes into account the spatial variability of the quantities affecting leakage.     

ANALYSIS OF FIRST TRANSIENT PRESSURE OSCILLATION FOR LEAK DETECTION IN A SINGLE PIPELINE

The leak detection is of great importance in the reliable operation and management of a pipeline system. Recently,attention is shifted to the use of the time domain or frequency domain methods based on the transient analysis. These methodssometimes require accurate pressure signals obtained during the transient period or by creating ideal conditions in testing. This paperproposes a method that does not require transient simulations over the whole or an extended period of time, but uses the first transientpressure oscillation to detect leaks. The method considers the propagation of the pressure oscillation wave created from a fast valveclosure and the reflected damp wave from the leak. A leak in the pipe gives rise to reflected waves which in turn creatediscontinuities in the observed signal at the measurement section. The timing of the reflected damp wave and the magnituderepresent the location and the size of the leak, respectively. An analytical expression is derived based on the Method OfCharacteristic (MOC) for the relationship between the leakage and the reflected magnitude. The leak detection procedure based onthe method is also given. Then the reliability of the method is tested on numerically simulated pressure signals and experimentalpressure signals with calibrated leak parameters, and the results indicate a successful application and the promising features of themethod.     

节点流量和水损系数的不确定性对供水管网水力特性的影响

供水管网的节点用水量和水损系数具有明显的不确定性,为研究节点用水量和水损系数的不确定性对供水管网水力特性的影响,提出了在假定他们的随机变化服从正态分布的条件下,采用蒙特卡罗随机抽样法,对所获的每组节点用水量和水损系数的抽样值,应用稳态的水力模型计算相应的节点测压管水头和管段流量,得出节点测压管水头和管段流量的统计值的计算方法。文中给出了该算法在两管网中的应用。     

埋地异型供水管段泄漏定位方法

供水管道泄漏时产生泄漏声波,根据泄漏声波到达安装在管道上的两个传感器的时间差,可以估计出泄漏位置。泄漏声波在管道中的传播速度与管道材料、内径和壁厚等有关。当泄漏发生在由不同类型管道组成的管段上时,用平均声速计算泄漏位置会增大定位的不确定度。借助于供水管网信息化提供的地下管线详实信息,根据各段管道的长度和声速可以更准确地估计出泄漏位置。介绍了异型管段泄漏定位的计算方法,给出一个检测实例和算法的流程。     

Leakage Estimation in Water Distribution Network: Effect of the Shape and Size Cracks

Water Resources Management - The definition of the relationship between the leak outflow, the total head at the leak and other relevant parameters such as pipe stiffness, leak dimension and shape...     

Monitoring of Pressure Transients in Water Supply Networks

Ageing water infrastructure is one of the major problems faced by water utilities around the world at present, and urgent solutions are required in order to maintain the integrity of the water supply network. In order to use pipe failure prediction models, accurate information about loads acting on these pipes is important. Water pressure (steady-state and transient) is one of the key loads that needs to be estimated accurately in order to improve the predictability of pipe failures. This paper reports the results of a pressure monitoring program, which was conducted to measure pressure fluctuations during events of pressure transients in three selected network sections in Australia. Pressure measurements were conducted in network sections which were considered as susceptible to pressure transients. Potential sources of pressure transients were identified, and high speed data loggers were installed in selected locations of each network to measure and monitor pressure transients. Pressure transients that were generated during normal operation were measured for a period of one month in each selected section. Further, some of the pressure transients were manually made to simulate the different pressures due to pump start-ups within the network. Pressure fluctuations that could potentially lead to pipe failures were measured at many locations during the monitoring program (several selected failures were reported in this article). Therefore, the effect of pressure transients must not be ignored in pipe failure prediction.     

Effects of Pipe Roughness Uncertainty on Water Distribution Network Performance During its Operational Period

The design of new water distribution networks (WDNs) is an important social problem. Failures during an operational period provoke deficits in consumption nodes thus decreasing the performance of the network. WDN performance can be defined as the ability to sufficiently secure demand and desirable pressure in nodes based on changes in design parameters. This paper focuses on the evaluation of network performance during an operational period, taking into account pipe roughness uncertainty. A network analysis is performed by generating probabilistic series of pipe roughness using Monte Carlo simulation (MCS) in the operational period of the Two-loop WDN. Results show that an increase in pipe roughness uncertainty causes a decrease in network performance in the operational period. Furthermore, the network has a desirable efficiency only in the first 10 years. Thus, the proposed design methodology that considers the uncertainty of design variables is an effective procedure to evaluate network performance.