Customer Meter Research Articles

Application of a water balance adapted to intermittent water supply and flat-rate tariffs without customer metering in Tiruvannamalai, India

Abstract Establishing the water balance developed by the International Water Association (IWA) is a worldwide applied approach to determine and analyse water losses in water distribution systems (WDS). The water balance covers those parts of a WDS within the responsibility of the water utility. Water losses occurring ‘before’ a customer meter are at the expense of the utility, while water lost or wasted ‘after’ the meter is paid for by the customer. This applies to systems where customer metering is in place and/or consumption is charged according to the consumed volumes. However, many WDS in the world lack customer meters, are operated intermittently and apply flat-rate tariffs. In intermittent supplies, a considerable amount of water is lost or wasted within the private properties. The flat-rate tariff might not cover this amount or part of the amount. Thus, actual consumption and wastage should be separately quantified with respect to the utility's water reduction measures. Accepting the described conditions, the authors have developed an adaption of the IWA water balance and the methods to establish the balance. In this paper the application of the developed approach in an initially unmetered WDS with intermittent water supply in the city of Tiruvannamalai, India, is presented.

Adaptive Kalman Filter Based on Adjustable Sampling Interval in Burst Detection for Water Distribution System

Rapid detection of bursts and leaks in water distribution systems (WDSs) can reduce the social and economic costs incurred through direct loss of water into the ground, additional energy demand for water supply, and service interruptions. Many real-time burst detection models have been developed in accordance with the use of supervisory control and data acquisition (SCADA) systems and the establishment of district meter areas (DMAs). Nonetheless, no consideration has been given to how frequently a flow meter measures and transmits data for predicting breaks and leaks in pipes. This paper analyzes the effect of sampling interval when an adaptive Kalman filter is used for detecting bursts in a WDS. A new sampling algorithm is presented that adjusts the sampling interval depending on the normalized residuals of flow after filtering. The proposed algorithm is applied to a virtual sinusoidal flow curve and real DMA flow data obtained from Jeongeup city in South Korea. The simulation results prove that the self-adjusting algorithm for determining the sampling interval is efficient and maintains reasonable accuracy in burst detection. The proposed sampling method has a significant potential for water utilities to build and operate real-time DMA monitoring systems combined with smart customer metering systems.

Off-line tracking of series parameters in distribution systems using AMI data

In the past, electric distribution systems have lacked measurement points, and equipment is often operated to its failure point, resulting in customer outages. The widespread deployment of sensors improves distribution level observability. This paper presents an off-line parameter tracking procedure that leverages the increased deployment of distribution level measurement devices to estimate changes in impedance parameters over time. Parameter tracking enables the discovery of non-diurnal and non-seasonal changes, which can be flagged for investigation. The presented method uses an unbalanced distribution-system state-estimator and a measurement-residual based parameter-estimation procedure. Measurement residuals from multiple measurement snapshots are combined to increase effective local redundancy and improve robustness to measurement noise. The input data used in the experiments consists of data from devices on the primary distribution system and from customer meters, via an AMI system. Results of simulations on the IEEE 13-Node Test Feeder with 307 measurements and 246 parameters are presented to illustrate the proposed approach applied to changes in series impedance parameters. The proposed approach can detect a 5% change in series resistance elements with 2% measurement error using less than 1 day of measurement snapshots for a single estimate.

Losses in Water Distribution Networks: A Practitioners' Guide to Assessment, Monitoring and Control

This is a best practice manual for addressing water losses in water distribution networks worldwide. Systems and methodologies are presented for improving water loss and leakage management in a range of networks, from systems with a well-developed infrastructure to those in developing countries where the network may need to be upgraded.The key feature of the manual is a diagnostic approach to develop a water loss strategy - using the appropriate tools to find the right solutions - which can be applied to any network. The methods of assessing the scale and volume of water loss are outlined, together with the procedures for setting up leakage monitoring and detection systems. As well as real losses (leakage) procedures for addressing apparent losses, by introducing regulatory and customer metering policies are explained. Suggestions are made for demand management and water conservation programmes, to complement the water loss strategy. Recommendations are made for training workshops and operation and maintenance programmes to ensure skills transfer and sustainability. The manual is illustrated throughout with case studies.Losses in Water Distribution Networks will appeal to a wide range of practitioners responsible for designing and managing a water loss strategy. These include consultants, operations managers, engineers, technicians and operational staff. It will also be a valuable reference for senior managers and decision makers, who may require an overview of the principles and procedures for controlling losses.The book will also be suitable as a source document for courses in Water Engineering, Resource Management and Environmental Management.ISBN: 9781900222112 (Print)ISBN: 9781780402642 (eBook)

Evaluation of AMI and SCADA Data Synergy for Distribution Feeder Modeling

Distribution system states have become more dynamic due to the integration of intermittent distributed generation/load and bi-directional power flows. The availability of close to real-time distribution system models will help the controls and customer participations in the active distribution networks. A framework using on-line and off-line computing power and data in existing distribution management system to work together and build distribution feeder models for operation purposes is proposed. Simulations and evaluation results of the synergy of big heterogeneous topological and measurement data from systems that have different data formats, polling cycles, and accuracy to establish immediate past and future feeder models are presented. Archived customer meter interval and supervisory control and data acquisition (SCADA) data with the same time stamp are used to build quasi dynamic models off-line, and to forecast the states and measurements at the feeder buses. The results are then used in the on-line quasi dynamic state estimations (DySEs). The state tracking capability of two DySE techniques in conjunction with a static state estimator under various data accuracy assumptions is evaluated. Numerical results demonstrate the benefit of data synergy in the improvement of system operation models and network efficiency.

Direct Measurements Show Decreasing Methane Emissions from Natural Gas Local Distribution Systems in the United States

Fugitive losses from natural gas distribution systems are a significant source of anthropogenic methane. Here, we report on a national sampling program to measure methane emissions from 13 urban distribution systems across the U.S. Emission factors were derived from direct measurements at 230 underground pipeline leaks and 229 metering and regulating facilities using stratified random sampling. When these new emission factors are combined with estimates for customer meters, maintenance, and upsets, and current pipeline miles and numbers of facilities, the total estimate is 393 Gg/yr with a 95% upper confidence limit of 854 Gg/yr (0.10% to 0.22% of the methane delivered nationwide). This fraction includes emissions from city gates to the customer meter, but does not include other urban sources or those downstream of customer meters. The upper confidence limit accounts for the skewed distribution of measurements, where a few large emitters accounted for most of the emissions. This emission estimate is 36% to 70% less than the 2011 EPA inventory, (based largely on 1990s emission data), and reflects significant upgrades at metering and regulating stations, improvements in leak detection and maintenance activities, as well as potential effects from differences in methodologies between the two studies.

Estimation of methane emission from California natural gas industry

Energy generation and consumption are the main contributors to greenhouse gases emissions in California. Natural gas is one of the primary sources of energy in California. A study was recently conducted to develop current, reliable, and California-specific source emission factors (EFs) that could be used to establish a more accurate methane emission inventory for the California natural gas industry. Twenty-five natural gas facilities were surveyed; the surveyed equipment included wellheads (172), separators (131), dehydrators (17), piping segments (145), compressors (66), pneumatic devices (374), metering and regulating (M&R) stations (19), hatches (34), pumps (2), and customer meters (12). In total, 92,157 components were screened, including flanges (10,101), manual valves (10,765), open-ended lines (384), pressure relief valves (358), regulators (930), seals (146), threaded connections (57,061), and welded connections (12,274). Screening values (SVs) were measured using portable monitoring instruments, and Hi-Flow samplers were then used to quantify fugitive emission rates. For a given SV range, the measured leak rates might span several orders of magnitude. The correlation equations between the leak rates and SVs were derived. All the component leakage rate histograms appeared to have the same trend, with the majority of leakage rates <0.02 cubic feet per minute (cfm). Using the cumulative distribution function, the geometric mean was found to be a better indicator than the arithmetic mean, as the mean for each group of leakage rates found. For most component types, the pegged EFs for SVs of ≥ 10,000 ppmV and of ≥ 50,000 ppmV are relatively similar. The component-level average EFs derived in this study are often smaller than the corresponding ones in the 1996 U.S. Environmental Protection Agency/Gas Research Institute (EPA/GRI) study.Implications: Twenty-five natural gas facilities in California were surveyed to develop current, reliable, and California-specific source emission factors (EFs) for the natural gas industry. Screening values were measured by using portable monitoring instruments, and Hi-Flow samplers were then used to quantify fugitive emission rates. The component-level average EFs derived in this study are often smaller than the corresponding ones in the 1996 EPA/GRI study. The smaller EF values from this study might be partially attributable to the employment of the leak detection and repair program by most, if not all, of the facilities surveyed.

Data driven analysis of customer flow meter data

With a growing amount of data available about drinking water distribution systems from customer meters and other monitoring, it is important to transform this data into information to enable water utilities to operate more efficiently and proactively. Comparison of flow pattern distribution (CFPD) analysis is a method that compares datasets and identifies inconsistent and consistent changes. Previously this has been applied at DMA and system wide levels, but not for single dwellings. This paper presents the results of CFPD analysis retrospectively applied to customer meter data, demonstrating its potential.

Evaluation of statistical sampling for the assessment of residential consumption totals in water distribution networks

The paper provides insights into stratified sampling, a standard statistical technique that may be employed to assess domestic water use in water distribution networks. The basic idea is to use only a few meters to provide inference on the total water consumption of a network or of a district metered area through the knowledge of some additional stratification variables, such as household typology, size and occupants number. Since any sampling procedure assumes that the variance of the variable at stake is known, either a suitable amount of past consumption data is necessary, or a specific preliminary survey must be carried out, in order to define the sampling plan. An application with real consumption data from a small municipality in Sicily (Italy) shows that number of occupants for each household is sufficient to design an effective sampling plan and that the methodology can be successfully applied in the technical practice, thus allowing a dramatic reduction of the number of customer meters to be read in order to quantify total water consumption compared to standard practice based on the reading of all meters.

Assessing the performance of urban water networks across the EU Mediterranean area: The paradox of high NRW levels and absence of respective reduction measures

The aim of this paper is to assess the performance level of water distribution systems (WDS) in six areas located in four Mediterranean countries, and evaluate their common characteristics. The second modification of the IWA Standard International Water Balance was used to account for the fixed charge included in the customers' bills. Each WDS efficiency was annually assessed, although in particular cases, shorter time periods (6 and 4 months) were applied depending upon local conditions, data availability, etc. The main common characteristic found was that some data needed to perform water balance calculations were missing (e.g. regarding the level of unbilled authorized use, unauthorized use, and customer meter inaccuracies). Moreover, a fixed-charge billing policy was adopted by the local utilities in all six cases, underestimating the impact of the high non-revenue water (NRW) values. This policy results in misleading, low values of unrecoverable revenues, although water losses remain high. Thus, water utilities are not motivated to develop NRW reduction strategies. Nevertheless, the analysis revealed that real losses represent the main NRW component in all case studies, thus respective reduction strategies should focus on them. Wherever WDS monitoring, simulation and leakage reduction measures were established, lower NRW values occur.

Non-Technical Loss Detection Using State Estimation and Analysis of Variance

Illegal use of electric energy is a widespread practice in many parts of the world. Smart metering enables the improvement of customer load model, theft and stressed asset detections. In this paper, a state estimation based approach for distribution transformer load estimation is exploited to detect meter malfunction/tampering and provide quantitative evidences of non-technical loss (NTL). A measure of overall fit of the estimated values to the pseudo feeder bus injection measurements based on customer metering data aggregated at the distribution transformers is used to localize the electricity usage irregularity. Following the state estimation results, an analysis of variance (ANOVA) is used to create a suspect list of customers with metering problems and estimate the actual usage. Typical Taiwan Power Company (TPC) distribution feeder data are used in the tests. Results of NTL detection under meter defect and energy theft scenarios are presented. Experiences indicate that the proposed scheme can give a good trace of the actual usage at feeder buses and supplement the current meter data validation estimation and editing (VEE) process to improve meter data quality.

Stimulus Dollars Fund Green AMI System In West Virginia

This article announces that the West Virginia Department of Health and Human Resources has selected West Virginia American Water as the recipient of $3.85 million in American Recovery and Reinvestment Act economic stimulus funding. The money will be used for a U.S. Environmental Protection Agency‐approved “green” project involving the installation of an advanced metering infrastructure (AMI) system. The pilot project, which will serve approximately 12,000 customers in Fayette County, will transmit water consumption data collected at customer meters to the company's computer network daily via radio frequency. Employees can then evaluate the data not only for billing purposes, but also to uncover irregularities such as a water leak on a customer's property.

Distribution Feeder Voltage Regulation Control

Step voltage regulators are the workhorse of distribution feeders for maintaining the voltage at every customer's meter to be within the ANSI standards. A step voltage regulator can be viewed as a tap-changing autotransformer. This paper will apply a model of the step voltage regulator. The IEEE 13 Node Test Feeders will be used to demonstrate how the regulator is controlled in order to maintain the desired voltage for full-, light-, and future-load conditions. The coordination of step voltage regulators with shunt capacitors will be included.

Water Loss Assessment and Remediation in South and Southeast Asia

One of the major challenges facing water utilities around the world but especially in Low and Middle Income Countries (LAMIC) is the high level of water losses either through physical losses (leakage) or commercial losses (customer meter under-registration and theft of water in various forms). This difference between the amount of water put into the distribution system and the amount of water billed to consumers is known as “Non-Revenue Water” (NRW). Levels of NRW in South and Southeast Asia are among the highest in the world. This paper will give an update of the general NRW situation in the various countries and the ongoing remediation measures.

Pressure Zone Audits Pinpoint Water Loss

This article discusses how automatic meter reading (AMR) with data‐logging functions and hourly system comparisons allow utilities to analyze new levels of detail in system supply and customer demand. This information helps utilities better understand water losses and whether the losses result from inaccurate meters, system leaks, or water theft. The article offers an example of California's East Bay Municipal Utility District evaluating the conservation benefits of mobile and fixed‐network AMR systems, equipped with data‐logging capabilities, in two pressure zones known as Round Hill and Holly. The goal was to determine the true nature of lost water – leaks, flushing, fire flow, system meter error, customer meter error, theft, leaks from one zone to another, or any combination of these factors. In addition to AMR and data‐logging‐equipped customer meters, the audit used historical hourly supervisory control and data acquisition (SCADA) operations data for flow rates and reservoir level indicators, acoustic leak‐detection equipment, and customer‐meter testing equipment. Audit details are provided, along with study findings. Field tests revealed that apparent losses are evident from graphical analysis. The leakage survey revealed no significant distribution system leaks within the pressure zones. Slow customer‐side leaks, especially on large meters, are sleeping giants of system loss within pressure zones.

Identification of key local factors influencing revenue water ratio of Korean cities using principal component analysis and clustering analysis

In order to identify the relation between revenue water (RW) ratio and key local factors in a quantifiable way, 90 effect factors were considered as regional characteristics for 79 Korean cities. Seven statistically significant effect factors were chosen through correlation analysis. Three principal components independently influencing RW ratio were extracted by principal component analysis (PCA). The 79 cities were grouped into six clusters by k-means clustering (KMC) of the factor scores of the cities. Then key local factors were identified and their impacts were quantified by multiple regression analysis (MRA) and they were justified by T-test and F-test. The approach through correlation-PCA-KMC-MRA was proved to be one of scientific ways for identification of key local factors. According to the result, it was suggested that a shorter length of distribution system, a water supply with smaller number of bigger customer meters a and gravitational supply through reservoir would be advantageous from a RW ratio's point of view.

Handle High‐Flow Rates with Ease

This article discusses various meters that can help a water utility account for water pumped through the distribution system and to equitably charge customers for the water they use. Two basic types of meters are discussed, positive displacement and inferential. Specifically, compound, turbine, propeller, and fire‐service meters are discussed. Criteria for selecting the correct meter size is given, along with general rules for commercial customer metering.

Teaming Up to Clarify Communications

This article describes how the Las Virgenes (California) Municipal Water District (LVMWD) redesigned its structure in order to achieve greater clarity and consistency in customer‐related communications. Going from an organizational structure based on bureaucratic “silos” that separated field and office functions relating to customers, LVMWD decided to combine Public Outreach, Office Customer Service, Billing, Meter Reading, and Field Customer Service into a single department. LVMWD used the method of looking at itself through the eyes of the customer to determine how to reorganize to achieve the greatest efficiency for its customers.

2002 Gimmicks and Gadgets Contest Blue Box Snares Top Honors

Dallas County Water Control and Improvement District No. 6 employees wanted a way to test customer meters onsite. Before they built the testing device, a meter had to be removed, replaced, and taken to the shop to be tested. So, they created a Blue Box with everything in it to test the meters on site. The Blue Box helps determine whether a meter needs replacing without pulling it, taking it to the shop, and testing it. This saves the district time and money, and keeps customers happy by knowing that their meters are reading accurately.

Whose Responsibility Are Leaks, Anyway?

This question of the month is about determining where responsibility begins and ends for the customer and the utility. The article specifically discusses a call to the Small Utility Network from a lawyer who was representing a customer of a small water utility. The customer's meter was inside the home, and there was a leak at the connection of the service line to the meter yoke. The customer claimed that this situation had occurred two or three times in the past and that the utility had responded to his call and serviced the problem. However, on the most recent occasion, a leak occurred when the home owner was not at home. The leak caused considerable damage and a high water bill. The issue: were the respective responsibilities of the utility and the home owner ever clearly defined and communicated by the utility to the home owner? The events leading up to the dispute were viewed differently by the parties involved, and legal council was required to resolve the issue.