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Smart Water Networks need Smart Data Presentation L. Stakenborg*, E. Trietsch** and B. de Graaf** * Quasset, Seinstraat 20, 1223 DA, Hilversum, the Netherlands (E-mail: [email protected]) ** Vitens, PO Box 1205, 8001 BE, Zwolle, the Netherlands (E-mail: [email protected] and [email protected])
Abstract The increasing use of sensors in water distribution networks is generating vast amounts of data. This data will only be valuable if presented to users (operators, analysts and management) in an effective and efficient way. This paper describes the approach and results achieved in Vitens using a web-based, GIS oriented presentation layer, integrating real-time sensor data and network and customer data from multiple data sources. Keywords Smart water networks, sensors, real-time data, data integration, presentation layer, Vitens, Quasset, IMQS, GIS, browser based.
Smart Water Networks Water utilities create and maintain an ever growing amount of data on their business operations and infrastructure. The increasing use of sensors that monitor the networks in real-time is even accelerating the rate at which the amount of data is increasing. However, all this data is only of real business value if it is used to support analysis and decision making. Ensuring that users (e.g. operators, analysts and management) are presented with network information in an effective (meaningful/relevant) and efficient (easy-to-use, responsive) way is therefore a key success factor for Smart Water Networks. In this paper we share the approach and results achieved in the Vitens Innovation Playground (VIP). Quasset[1] is working with Vitens to provide a web-based, GIS oriented information presentation layer on top of existing data sources containing network, customer and real-time sensor data. The work is part of SmartWater4Europe[2], an EU FP7 project that shows water innovation in the demo sites of Vitens, Acciona, Thames Water and the Université de Lille. Vitens[3], the largest water utility in the Netherlands, is testing innovative solutions in the Vitens Innovation Playground (VIP), a dedicated area comprising 5% of the total network. The goal of the VIP is to test new solutions and tools that help build the business case before being rolled out to the whole of Vitens. Currently information about the network is contained in multiple data sources, e.g. a network database, hydraulic modelling tools, customer databases and sensor data. Many types of sensors are deployed in the VIP, measuring physical properties like flow, pressure, temperature, conductivity and water quality (e.g. with Optiqua sensors). In addition, soft sensors represent computational outcomes, e.g. net flow to DMAs (District Metered Areas) and leak detection algorithms.
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Software architecture The figure below shows the software architecture at the Vitens demo site:
Figure 1: Software architecture at Vitens demo site
Real-time data platform All sensor data is collected in a real-time data platform, based on the OSIsoft[4] PI system. At the heart of PI is a data historian: a data collection and retrieval system optimized for time series of data. The real-time data platform provides a central location to interface with and collect data from a wide variety of sensors. In addition, soft sensors (algorithms using sensor data as input) can be implemented in PI. IMQS presentation layer The presentation layer is provided by IMQS[5], a web-based, GIS oriented system, integrating real-time data and network and customer data from multiple sources. The IMQS presentation layer presents network and sensor information in a geospatial context, for example the location of sensors in DMA zones:
Figure 2: DMAs in the VIP area (blue areas) and sensor locations (purple dots)
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A user can select several map themes to quickly view and compare pipe details such as year of construction:
Figure 3: Map theme 'Year of construction’'
Other themes include pipe material, pressure, flow direction and system type. Detailed data about pipes, DMAs, hydraulic regions, production sites and sensors are displayed by selecting the objects on the map.
Figure 4: Display properties of a selected pipe
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Real-time data and historic trends Users have immediate access to current values through the property pane on the right. Clicking on values provides historic trends of the sensor data:
Figure 5: Historic trends of a selected sensor measurement
Feedback from Vitens’ users shows that the user interface is both responsive (quick to navigate and display data) and easy to use (avoiding deeply nested menu structures). This is especially important for e.g. operators. Flow map Not only does the geospatial presentation provide an intuitive way to access the information at various aggregation levels (e.g. zooming in from region, via a city, all the way to street level), it also offers the opportunity for novel information tools. A good example is the Flow map, which displays flow arrows proportionate to the actual flow measured at sensor locations. The flow map is a tool to quickly identify the location area of a large break (by just following the flow). The time slider at the bottom can be used to go back in time which is useful in a post-event analysis or when comparing night/day patterns.
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Figure 6: Flow map with time slider
Sensor measurements, states and event notifications Sensors provide a time series of measurement values of (continuous) physical properties, e.g. water
temperature in degrees Celsius. It is often useful to categorize these values in value bands, e.g. too
low, low, normal, high and too high. Thresholds or other decision logic can be used to categorize the
measurement value into these so called ‘states’. State transitions signal events.
This relationship between these concepts is illustrated in the figure below.
Figure 7: Measurement values and states
Sensor states also have associated alarm levels (normal, warning, alarm and error). Warning and alarm events are pushed immediately from PI to IMQS and to the user’s browser. This provides a map of events:
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Figure 8: Notifications for Water Quality, Pressure, Leak detection and Temperature events
The warning/alarm events can be used to trigger appropriate response procedures. Sensor metadata repository The network of sensors deployed in the Smart Water Network is quite dynamic: sensors get (re)placed or relocated, sensors may temporarily be out-of-service, new sensor types from other vendors may be added, etc. To accommodate these changes, the presentation layer needs to have access to a central, up-to-date repository of data about the sensors, i.e. sensor metadata (e.g. their location, vendor, model, operational status, type etc.). We designed the following logical data model to structure the sensor data in this repository:
Sensor location
Sensor parameter
Sensor device
State EventMeasurement
Info layer
Info object
Sensor network
(Dynamic) property
Figure 9: Logical data model for sensor data and metadata
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A sensor network is essentially a collection of sensor devices. It is useful to allow for multiple sensor networks (e.g. representing water quality sensors, pressure sensors, etc.). Each sensor device measures one or more physical properties, referred to as sensor parameters. Each of these sensor parameters has associated measurements (a time series of values), states and events. Furthermore we have identified the minimum required set of attributes and verified that the model caters for a range of physical and soft sensors being used in the Vitens demo site. The right-hand side illustrates how the sensor data is presented by IMQS: sensor networks are represented as (GIS) layers, sensors as selectable objects inside these layers and sensor parameters are considered as the dynamic (or real-time) properties of sensor objects. Based on the model, the sensor metadata repository has been implemented in Vitens PI real-time data platform, using PI-AF (PI Asset Framework). IMQS and PI are connected through a JDBC interface and Web services are used for event notifications.
Figure 10: Sensor repository in PI-AF
RESULTS In conclusion, the following results have been achieved in the Vitens Innovation Playground:
A wide variety of sensors have been installed in the Vitens demo site. Both physical sensors measuring Pressure, Temperature, Flow, Water Quality, as well as soft sensors (algorithms) for leak detection, energy efficiency, net flows, etc.
Sensor data is centrally collected and stored in a real-time data platform based on the OSIsoft PI system.
A sensor metadata repository based on OSIsoft PI-AF has been designed and implemented, keeping track of all the data about the sensors that are available in the network.
A web-based, GIS oriented presentation layer based on IMQS provides a single, integrated and user-friendly interface to multiple data sources.
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The geospatial presentation and access to information offers novel means to interpret and act on real-time data, e.g. the localization of pipe bursts. It also demonstrates the added value of offering sensor data in the context of other relevant asset and customer information.
It also has been very effective in presenting the outcomes of various activities and themes in the VIP to the senior management and other stakeholders.
Within the SmartWater4Europe program we will continue to build on these results and provide opportunities for other water utilities to visit and learn more from the Smart Water Network demo sites. REFERENCES [1] Quasset: http://www.quasset.com [2] SmartWater4Europe: http://www.smartwater4europe.com [3] Vitens: http://www.vitens.nl [4] OSIsoft: http://www.osisoft.com [5] IMQS: http://www.imqs.co.za
