小投入大产出——《移动式DMA测试装置提供了一种主动的漏损管理策略》

原文链接：

https://awwa.onlinelibrary.wiley.com/doi/epdf/10.1002/opfl.1663

原文作者：

BRADLEY W. JENKS AND FABIAN PAPA

原文出处：J Opflow

翻译：阮辰旼

Mobile DMA Unit Provides a Proactive Leakage Management Strategy

移动式DMA测试装置提供了一种主动的漏损管理策略

It’s well understood that leakage in water distribution systems (WDSs) has adverse financial and environmental impacts, especially amid the growing concern of depleting water and energy resources. Moreover, conserving water through leakage reduction efforts may defer the indirect (and often significant) costs linked with expanding system capacity to meet rising demands. Put simply, reducing WDS leakage saves a utility money and lessens its carbon footprint. For many water utilities, leakage management is primarily reactive. That is, leaky pipes are repaired only when leaks are visible and, by that time, have released a significant volume of water into the surrounding environment, potentially causing damage to nearby infrastructure. On the other hand, the main objective in a proactive leakage management strategy is to identify leaks before they surface. This reduces the leak runtime, which, combined with its rate of flow, aggregates to the volume of lost water.

众所周知，供水输配系统（WDSs）的漏失对财务运行和环境都有不利影响，特别是在水和能源资源日益紧缺的情况下。通过减少漏失来节约用水，可以扩大供水系统的实际供水能力以满足不断增长的需求，节约有关的间接成本（通常是巨大的）。简单地说，减少供水输配系统的漏失可以为水务公司节省资金并减少碳足迹。对于许多水务公司来说，漏损管理大多数是被动的。也就是说，只有在漏损现象明显时才会对发生漏损的管道进行维修，而且那时可能已经向周围环境释放了大量的水，有可能已经对附近的基础设施造成了损害。另一方面，积极主动的漏损管理策略的主要目标是在漏损问题出现之前就识别到渗漏。这就减少了实际漏损现象的持续时间，考虑到持续不停的流速，相当于避免了大量漏失掉的水。

A multiyear water loss testing program was undertaken in Ontario, Canada, to raise awareness of proactive leakage management practices. From a technical perspective, the ambitious testing program—sponsored primarily by the province’s Independent Electricity System Operator—employs a recognized best practice (particularly in the United Kingdom, where the concept originated) of observing flows into discrete sectors of a WDS, commonly referred to as district metered areas (DMAs).

加拿大安大略省开展了一项多年的供水漏失测试项目，以提高对主动漏损的管理做法的认识。从技术角度来看，这个雄心勃勃的测试项目主要由该省的独立电力系统运营商赞助，采用了公认的最佳实践方法（特别是在英国，这个概念的起源地），即观察多个计量区域内的供水流动情况，通常被称为分区计量方法（DMAs）。

DMA configuration involves hydraulic isolation of a subsection of the WDS. This is achieved by closing numerous boundary valves and monitoring flow and pressure at a supply inlet (or multiple inlets if applicable). The data collected at a DMA inlet help to optimize system operations. In terms of assessing leakage, the data allow operators to evaluate minimum night flow (MNF), which typically occurs between 2:00 a.m. and 4:00 a.m. MNF can be a valuable leakage indicator, as it represents an instance in the system when demand is at its lowest; thus, leakage constitutes the highest fraction of total flow. Accordingly, the MNF value, in conjunction with the DMA characteristics (e.g., number of connections and population), can be used to benchmark DMA performance.

DMA分区的配置包括对供水输配系统的一个分段进行水力上的隔离，通过关闭该区域众多边界阀门，只监测一个入口（或多个入口，如适用的话）的流量和压力来实现的管理方法。在DMA分区的入口处收集的数据有助于优化系统的运行。在以评估漏损为目标时，操作人员可以评估最小夜间流量（MNF）来获取数据，通常指凌晨2:00至4:00之间。最小夜间流量（MNF）可以成为一个有价值的漏损数据指标，因为它代表了该供水输配系统中用水需求最低值时的一个工况，因此，该分区中的实际漏损量就构成了进出水流量差值的最主要的部分。因此，最小夜间流量（MNF）与DMA的特征（如用水点接入数和人口数）一起，可用于评价DMA分区的实际情况。

Despite its benefits, implementing permanent DMA infrastructure (i.e., in-line flow-metering technologies) is not yet a widespread practice among North American water utilities. This is due, at least in part, to costly installation and operational challenges, including the following:

尽管DMA分区管理具有积极的帮助，但永久性地实行DMA管理，即始终安装并运行在线流量监测的基础硬件设施在北美水务公司中还不是一种广泛的做法。其中最基础的一个原因是由于昂贵的设备安装和运行费用，还包括以下原因：

■ Expensive flow-metering technologies, which often include the costly construction of chambers to house the metering equipment and telemetry devices

流量监测技术的成本高昂，通常包括昂贵的测量设备和远传设备的的建安费用

■ Potential of high water age due to dead ends at DMA boundaries

进行DMA分区管理后，分区的边界可能形成死角，会出现高水龄的情况

■ Increased head losses resulting from routing flow through one (or a few) supply points, leading to a pressure reduction within the DMA

由于水的流动路线被限制为一个（或几个），造成水头损失增加，从而导致DMA分区内的末端压力下降

■ Reduced system capacity for firefighting or exceptional water demand

可供消防或特殊用水需求的水量减少

■ Decreased resilience to failure events (e.g., a sudden depressurization)

对故障事件（如突然减压）的复原能力下降

With these drawbacks in mind, temporary metering solutions—such as insertion or clamp-on (transit time) flow meters—often are advised because of their relatively inexpensive installation as well as short-term DMA configurations. However, these technologies may be unable to reliably measure MNF rates where very low flow velocities are below the technology detection limit. Accordingly, as DMAs become smaller, it becomes increasingly difficult to obtain reliable data. Thus, a trade-off exists between data reliability and cost.

因为考虑到实行分区计量时的这些缺点，通常建议采用临时性计量的解决方案，如插入式或钳式（过境时间）流量计，因为这些设备的安装费用相对较低，而且适用于短期临时性的DMA计量工作需求。然而，这些临时性的计量设备可能无法可靠地测量流速低于检测限的MNF流速，获得可靠的数据的难度和DMA分区规模的大小成反比。因此，需要在确保数据的可靠性和成本的经济性之间找到一种权衡。

In light of this trade-off, the concept of developing a portable diagnostic tool emerged. A mobile testing unit was designed to enable accurate and reliable MNF measurements in temporarily configured DMAs by redirecting flow through taps (or hydrants) on either side of a closed valve (Figure 1). This concept was inspired by experimental research performed by the National Research Council of Canada and the City of Ottawa in the mid-2000s.

鉴于需要找到上文所提到的这种权衡，于是便出现了要开发一种便携式诊断工具的想法。我们设计了一个移动式的试验装置，通过在关闭的阀门两侧的水龙头（或消防栓）改变水流方向形成临时的DMA分区，进行准确和可靠的MNF计量（图1）。这一想法是受加拿大国家研究委员会和渥太华市在2005年前后的时期进行的实验研究启发的。

Figure 1. The mobile testing unit allows utilities to collect affordable, reliable operational data in district metered areas. Flows are redirected into the unit through tap installations or hydrants on the upstream and downstream sides of a closed valve (inset).

图1. 移动式测试装置使公用事业部门能够用承受得起的经济代价，在DMA分区计量区域内收集可靠的运行数据。水流通过关闭的阀门上下游的水龙头或消防栓流经测试装置。

The mobile unit consists of an in-line flow meter—appropriately selected to measure MNF rates accurately and reliably from relatively small DMAs—and an adjustable pressure-reducing valve (PRV), in addition to piping, ports, pressure gauges, and related fittings. Further, the hydraulic losses induced from flow passing through the mobile unit have been aptly characterized through theoretical calculations and thereafter verified using field testing results. Taking these losses into consideration has allowed for increased confidence when planning DMA sites, especially those near the upper limit of the mobile unit’s acceptable flow range and/or those with low operating pressures.

该移动式的试验装置包括了一个在线流量计，这个流量计具备准确可靠地测量相对较小的DMA分区的MNF流速的能力，也包括了一个可调节的减压阀（PRV），此外还有管道、堵头、压力表和相关配件。此外，通过理论计算比较准确地还原了流经该移动试验装置产生的水头损失，并通过现场试验的结果进行了验证。为了增加试验装置的可靠性，在考虑到这部分水头损失时，特别在规划DMA分区范围时，要特别关注到一些流量接近试验装置检测限上限，和/或工作压力比较低的点。

Compared to conventional DMA metering techniques, the mobile unit has several advantages, including the following:

与传统的DMA分区计量手段相比，该移动式测试装置有几个优点，包括：

■ Affordable by virtue of its spatial flexibility (i.e., redeployment to other DMA sites)

由于在应用空间上的灵活性，可以负担得起反复的部署（即可以重新部署到其他DMA分区）。

■ Reliable and accurate low-flow measurements from in-line flow-metering technologies equipped in the unit, otherwise typical of a permanent DMA installation

不需要传统的永久性安装的DMA分区计量设备，就可以通过移动式测试装置中配备的在线流量计对较低的流量进行计量。

■ Direct measurement of the pressure–leakage relationship through the activation of a PRV, flow measurements, and recorded average zone pressure

通过开关减压阀（PRV），就能直接测量流量、记录平均区域压力，获得压力和漏损之间的关系

■ Temporary hydraulic isolation of the system so as to not cause undesired operational consequences of implementing a permanent DMA arrangement Overall, the objective of deploying the mobile unit is to affordably collect reliable MNF data to compare against benchmarks representing well-performing (or “healthy”) systems, thereby helping users prioritize future leak detection activities.

通过对输配系统系统的临时性水力隔离措施，可以不用实施永久性的DMA分区措施，避免永久性的措施科能带来的不确定性后果。总的来说，部署移动式测试装置的目的是以可承受的经济代价获取可靠的MNF流量数据，用来与漏损状况良好（或“健康”）的输配系统的基准进行比较，从而帮助水务企业确定后续检漏工作的优先次序。

In addition to DMA test site selection and site reconnaissance to determine test site feasibility, two activities are required before testing. Apart from setup cases that use hydrant ports, the mobile unit connection requires proper installation of taps on either side of a valve within a chamber (as shown in the inset photo in Figure 1). This is followed by zero-pressure tests on DMA boundary valves to ensure complete closure is achieved, thereby confirming the hydraulic integrity of the temporarily configured DMA. Testing is then conducted for two to four nights during nonirrigation months (i.e., from October to May), with flow and pressure data collected at the DMA inlet from approximately midnight to 6:00 a.m. The objective of multiple nights of testing is to achieve reasonable duplicability of results and to test the effectiveness of pressure reduction in reducing leakage. The latter involves cycling between a reduced pressure setting (by activating the PRV) and full pressure conditions on a 30-minute cycling period to observe the DMA’s in situ pressure–leakage response. Sample plots for a typical full-pressure test and for a pressure cycling test are illustrated in Figures 2a and 2b. Note that pressure is also monitored at the critical point (i.e., hydrant with the highest elevation) to ensure acceptable service is being maintained in the DMA.

除了通过现场勘察，对DMA分区试验点的选择确定可行性外，测试前还需要进行两项工作。

除了直接利用消防栓的情况外，移动装置的连接需要在一个阀门井中的阀门两侧正确安装水龙头。（如图1中的插图所示）。

随后是对临时的DMA分区的边界阀做零压力测试，确保实现阀门完全的关闭，从而确认临时配置的DMA的水力完整性。然后在非灌溉月（即10月到5月）进行两到四个晚上的测试，从午夜到早上6点左右在临时DMA分区入口处收集流量和压力数据。多晚测试的目的是为了验证结果的合理重复性，并测试减压对减少漏失的有效程度。后者包括在减压条件（通过开启减压阀）和全压条件之间进行30分钟的循环，以观察临时DMA的现场压力变化和漏损现象的关联。图2a和2b显示了典型的全压试验和压力循环试验的数据图。请注意，在临界点（即标高位置最高的消防栓）也要监测压力，以确保临时DMA中始终保持着可接受的供水服务压力。

Figures 2a and 2b. Flow and Hydraulic Grade Line Data

图 2a 和 2b. 流速和水力坡度数据

Data were collected for a district metered area tested under normal operating conditions (2a). A pressure cycling test allowed operators to determine the in situ pressure and leakage response (2b).

正常运行条件下测试的DMA分区所获得的数据（2a）。

通过压力循环测试使操作人员能够确定测试区域内压力和漏损的关系（2b）。

In total, the MNF data collected from this testing program consist of 25 residential DMA test sites. The 60-minute average minimum night flow (MNF60) results for the overall data set, relative to DMA population and as a ratio to annualized average billed demand (ABD), are shown in Figures 3a and 3b, respectively.

总体上，这个测试项目共收集的MNF数据覆盖了有25个住宅的DMA计量分区。图3a和3b分别显示了整个测试结果的60分钟平均最小夜流量（MNF60），和DMA分区内人口，以及与年度平均应付账单（ABD）的关系。

Figure 3a shows that most of the data points (in blue) appear to form a lower envelope, progressing away from the origin. This data cohort is categorized as “healthy” DMAs, having minimal excess leakage. Through statistical analysis of these well-performing MNF60 data points (normalized to various size features of the DMA), benchmarks were developed to enable an objective, evidence-based assessment of leakage performance. These benchmarks are intended to act as a baseline for quantifying recoverable excess leakage, as represented by the dashed black line in Figure 3a. In addition to DMA size features, the fraction of MNF60 relative to average consumption rates (identified in this work as annualized ABD) within the DMA also were explored. The results of this analysis are illustrated in Figure 3b, which uses the same color theme as Figure 3a when identifying the relative performance categories (i.e., healthy or poorly performing). As observed with MNF60 normalized to population, a distinct separation is identified between well-performing, healthy DMAs and those with suspected excess leakage. This is generally as expected given the predictable diurnal demand profiles for residential consumers. Moreover, this benchmark is strengthened through typical estimates reported in the literature and previous project experience.

图3a显示，大多数的数据点（蓝色）似乎形成了一个较低的包络线，从原点向外延伸。这个数据群被归类为“健康的”DMA分区数据，只有最小的漏损情况。通过对这些表现良好的MNF60数据点的统计分析（根据DMA分区的各种范围特征进行归一化处理）制定了基准，以便对漏损情况进行客观的、基于基准的评估。这些基准旨在作为量化的可恢复的漏损的基线，如图3a中的黑色虚线所表示。除了DMA分区的范围特征外，还探讨了DMA分区内MNF60相对于平均水费消费情况（在这项工作中被确定为年化ABD）的部分。图3b说明了这一分析的结果，在确定DMA分区相对的表现类别（即健康或不健康）时，采用了与图3a相同的颜色类别区分。如同对MNF60的归一化观察，在表现良好、健康的DMA分度和疑似较严重漏损的DMA分区之间有明显的区别。这可以用来预测相关住宅用户的昼夜用水需求曲线此外，通过文献中报道的情况和以往的其他项目经验，可以进一步对这一基准的可靠性进行加强。

Figures 3a and 3b. 60-Minute Average Minimum Night Flow (MNF60) Data

图3a和3b. 60分钟平均夜间最小流量（MNF60）数据

MNF60 data points are plotted relative to DMA population to highlight recoverable excess leakage (3a). As an additional performance benchmark, MNF60 data points are also plotted as a ratio to ABD (3b). MNF60 data points are grouped in three categories: healthy DMAs (blue), poorly performing DMAs (red), and inconclusive data points (gray).

MNF60数据相对于DMA分区人口绘制的数据图，可以突出可恢复的过量漏失情况（3a）。作为一个额外的评价管网情况的基准，也可以绘制MNF60数据相对于ABD的数据图（3b）。MNF60数据点被标记为三类，分表代表：健康的DMA分区（蓝色），表现不佳的DMA分区（红色），以及不确定的数据点（灰色）。

In summary, the following benchmarks were developed:

综上所述，制定了以下基准：

MNF60 = 2.2 L/h/capita

（每个人口，每小时60分钟最小夜间流量2.2升）

MNF60 = 6.0 L/h/unit

（每个单元？ <暂不明确具体意义> ，每小时60分钟最小夜间流量6.0升）

MNF60 = 6.4 L/h/connection

（每个用水接入点，每小时60分钟最小夜间流量6.4升）

MNF60/ABD = 24%

（每小时60分钟最小夜间流量和年度平均应付账单的比值是24%）

Excess leakage can be approximately identified in Figure 3a as the vertical distance from the data point to the MNF60 benchmark. This is best demonstrated through the poorly performing outlier data points (in red), a grouping of DMAs showing a large departure from the healthy DMA cohort. Of these outlier DMAs, two were subjected to further leak detection and repair activities, followed by subsequent retesting using the mobile unit. The green and purple dashed arrows in Figures 3a and 3b illustrate the recovered leakage measured and verified through the post-repair deployment.

在图3a中，漏损的严重程度可以近似地识别为从数据点到MNF60基准的垂直距离。图中通过表现不佳的数据点（红色）可以直观的看到，红色的数据点与代表健康DMA分区（蓝色点）有较大的偏差。在这些红色的DMA分区数据点中，有两个接受了进一步的漏损检测和漏损修复，随后再次使用移动式测试装置进行了重新测试。图3a和图3b中的绿色和紫色虚线箭头说明了检测和修复工作前后漏损状况的改善情况。

In one exceptional case, the post-repair testing showed a considerable reduction in the MNF60 rate, verifying the reduction of approximately 264 L (~70 US gallons) per minute and bringing its performance in line with that of its healthier peers. This is equivalent to roughly the volume of water that otherwise would be consumed by a similar number of houses that were located in this particular DMA (~660). Moreover, the recovered leakage for this utility equated to a remarkable annual savings of just over Can$425,000, around 100 MW?h of power usage, and 4.1 tonnes of carbon dioxide (at 40 g CO2/kW?h). Put simply, diagnosing system conditions by collecting data (evidence) led to substantial financial and environmental savings for the utility.

在一个特殊的案例中，管道修复工作后的测试显示MNF60的数值大大降低，每分钟减少约264升（约70美加仑），表示该分区的运行状况与健康的分区基本一致，大约相当于拥有类似数量房屋的处于该健康状况的DMA分区的消耗的水量约660。此外，该公用事业公司挽回的漏水水量相当于每年节省42.5万加元，相当于大约100兆瓦小时的电力使用成本，以及相当于4.1吨的二氧化碳（按40克二氧化碳/千瓦小时计算）排放量。简单地说，通过收集数据来诊断输配系统漏损状况，可以为水务公司带来了大量的经济和环境上的节约。

The mobile unit—perhaps the only one of its kind globally—developed as part of this research program has proved successful as a diagnostic tool to guide decisions about water loss prevention, demonstrated through measured and verified water and energy savings in utilities across Ontario. Further, the approach has earned two awards and garnered international attention, with interest being shown from the United States, Europe, and Asia.

作为该研究项目的一部分而开发的移动式试验设备，也许是全球唯一的此类设备，已被证明是成功的漏损诊断工具，用于指导预防漏损的决策，这一点通过安大略省各地的公用事业公司实际测试和验证得到的水和能源的节约数据得到了证明。此外，该方法还获得了两个奖项，并获得了国际关注，美国、欧洲和亚洲都对其产生了兴趣。

The program’s results—in relation to the testing method and the performance indicator benchmarks—are applicable to water utilities across the United States and Canada given the similarity in design and construction standards. That is, any utility can compare the results from any residential DMA, however measured, to the benchmarks identified and have a sense as to whether and to what extent excessive leakage may exist. Also, the concept of the mobile unit is available for commercial application and industry duplication to support its widespread adoption.

考虑到与设计和建设标准的相似性，这个项目的成果，即通过试验和所取得的数据形成的参考基准，可以被应用于美国和加拿大的水务公司。也就是说，任何水务公司都可以将任何DMA分区的数据情况（无论如何测量）与上述的基准进行比较，以判断是否存在漏损以及存在多大程度的漏损。此外，这个移动式测试装置的思路可用于商业应用和行业复制，以支持其更为广泛的应用。