Water Journal : Water Journal May 2011
refereed paper demand management water MAY 2011 79 The IHD participants had the advantage of being alerted to any possible leaks in their home. Just over half the households completed the final survey and 55% of those households indicated that they noticed the 'potential leak alarm'. While 80% of those claimed to have looked for a leak to varying degrees, 40% actually found one or more leaks and had them repaired. Participants indicated that there were a number of limiting factors to having leaks repaired and these include costs, lack of time, convenience, lack of knowledge and skills. Network Leakage and Minimum Night Flow Estimates The trial has proved valuable in supporting the management of network leakage. The water consumption data generated is being used to develop a model of night-time water use to improve minimum night flow monitoring within networks. When finalised, the model should allow typical residential night usage patterns to be accurately depicted under varying weather and other conditions. This in turn will allow a better assessment of system leakage in different supply zones and the optimisation of leak detection efforts. Attempts to directly measure network leakage on a near real-time basis have been less successful. Uncertainties and discrepancies due to missing or erroneous bulk meter and/or AMR data were found to make short-term comparisons between supply and consumption an unreliable indicator of network leakage. Initially a network leakage figure of 2% was calculated for the Westleigh DMA. However, this figure is not a reliable leakage indicator, because the current method of transmitting the smart meter data wirelessly has not been perfected, and as such around 1--4% of consumption data was lost on a daily basis due to issues such as communication interference. Key Learnings As the trial tested the application and functionality of new technologies from the users' and utilities' perspectives, a great amount of flexibility and adaptability was required as the project evolved over time. Recruitment The recruitment of participants took a significant amount of effort. Although it commenced several months before the technology was installed, recruitment continued well beyond the deployment phase. The process involved letters to customers, articles in the local newsletter and information posted on websites and shopping centre community boards. It also included presentations at community meetings and local open days. Despite these efforts, further measures were required such as phone calls, emails and face-to-face meetings in order to follow up prospective trial participants. Technology In terms of the technology, there were numerous challenges in setting up the smart metering network. Installation of the Spider loggers on residential properties required the recruitment of customers in specific locations. While this option allowed for a constant and secure power supply there were issues in finding suitable locations and willing volunteers. Different scenarios were developed to overcome the problem of successful transmission of data between the AMR devices and the Spider logger. Difficult or unpredictable radio signals were caused by site geography, proximity of the smart metering components to each other, storms and obstacles such as buildings and parked trucks. Some properties proved unsuitable for the installation of an IHD due to poor data transfer between the AMR device and the IHD. A transmitter signal of greater than 30% of full strength was required to ensure the successful and continuous transmission of the data. Problems of defective or malfunctioning equipment were encountered, with more than 550 AMR devices being replaced, as some sites had multiple replacements. There were some minor incidents of theft and vandalism. When AMR devices were replaced that also had an IHD on the property, updating the AMR radio frequency information in the IHD required direct access to the device within the property and to the customer. Often there were no customers at home during working hours and, therefore, delays were incurred in rectification of faults and greater loss of data or IHD operational continuity. Data management Data reliability was also found to be an issue. The average monthly data transmission rates ranged from 84% to 99%, while individual transmission rates went as low as 27%. This current level of AMR data reliability would not be acceptable for billing purposes. The learnings from the project show that improvements to the technology and the communication set-up would be needed to minimise this issue in the future. As consumption data was measured on a household level, individual consumption within the home could not be measured in either the participant or the final survey. As an alternative strategy, the qualitative data provided a depth of understanding regarding consumption behaviour of individual household members. Both foreseeable and unforeseeable variables impacted on the consumption data throughout the trial. These included: • Heavy periods of rainfall ending the five-year drought; • Lifting of Level 3 Water Restrictions and the introduction of new Water Wise Rules; Figure 3: Average daily consumption.
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