WET News

MARCH 2017 WET NEWS 17 THE CONCEPT • Smart meters measure and transmit a customer's water usage data • The meters operate on their own or as part of a wireless network • Data reconciliation identifies the instruments responsible for imbalances, allowing water companies to target maintenance • DR is a calculation technique for monitoring the quality and reliability of flow measurement data NEED TO KNOW 1 Predictions show that water levels could drop by between 10% and 15% over the next few decades 2 In England and Wales, 3.3 billion litres of water are lost daily through leakage in the delivery network 3 A shortage of key skills may mean a substantial investment in re-training THE VERDICT "Smart metering and data reconciliation used together will give water companies much more confidence in the reliability of their data and the resilience of their networks from trunk main level, down to the supply to individual properties" Alick MacGillivray, NEL continuous battery powered network monitoring for residual chlorine t. 0800 8046 062 www.atiuk.com meters available from different companies falling into several categories such as mechanical meters, simple digital meters and upgraded mechanical meters. These meters cost in the region of £250 to install and are paid for by the customer. It is anticipated that smart meters will reduce bills in most households by assisting in the identification of leaks. Some companies are also considering the introduction of "seasonal tariffs" which is expected to help with demand management. Practically, this means that customers would be charged more during periods of water scarcity. These meters are much cheaper to read than existing equipment and are generally more accurate. Because they can transmit a large volume of data they allow the company to manage their network much more efficiently. Data reconciliation In the past, water companies have used mass balance techniques to estimate the amount of leakage and other unmetered abstraction in their distribution and waste treatment flow networks. Data reconciliation (DR) takes this a stage further by identifying the instruments most likely to be responsible for imbalances, and allowing water companies to target maintenance to where it is most required. DR is a calculation technique that is increasingly being used by water companies to monitor the quality and reliability of flow measurement data acquired from trunk mains. It performs a network self-check to ensure that all of the measuring devices are consistent with each other. Using this technique, engineers may quickly identify which meters are reading outside their uncertainty bands and take appropriate remedial action. It can also be used to determine the level of leakage in a network. The basic premise behind data reconciliation is that it uses a mathematical technique known as 'least squares' to adjust the values of the measured flows so that they all exactly obey the balance equations in the network. The magnitudes of the numerical adjustments required to do this are compared with the uncertainty of the measurement (to 95% confidence) and a "quality index" is calculated for each measurement point in the network. If the value of this index is less than unity then the measurement is deemed acceptable; if greater, then there is an issue with the measurement that should be investigated. The calculations are normally performed using DR so"ware installed as part of the water company's data historian. It is common that the calculations are triggered along with others during the minimum nightline period, usually on a daily basis. In this way, it can act as an "early warning" system for instruments dri"ing out of calibration or the development of leaks in the trunk mains. Companies using this technique have much more confidence in their trunk main flow data, as it is continuously being checked for consistency against the rest of the network. It also can substantially reduce Opex due to reduction in the level of maintenance required. Smart metering and data reconciliation used together will give water companies much more confidence in the reliability of their data and the resilience of their networks from trunk main level, down to the supply to individual properties. These techniques, along with recent advances in electronics and computing will go a long way to meeting the challenges facing water companies in the 21st century. Alick MacGillivray is senior consultant at NEL. Diehl Metering offers innovative solutions for an optimal management of your water systems. The new generation of IZAR RC i W G4, OMS compatible, has been launched. IZAR RC i Waterbox G4 is designed for mobile and fixed-network reading and includes the new data logger function. The ALTAIR range of water meters and IZAR RC 868 i W G4 combined with the new IZAR Software (IZAR PLUS PORTAL) offers a complete solution for data reading and management More information: www.diehl.com/metering or sales.uk@diehl.com Smart Metering Discover solutions that count © QQ7 - Fotolia.com

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