Networking helps cut losses
Steve Mustard, Logica's telemetry business manager and Simon Harrison, Anglian Water's telemetry project manager explain why telemetry is vital to Anglian's bid to cut water loss
To gain full benefit from the telemetry infrastructure, Anglian worked with Logica to develop a district metering system (DMS). As with most water companies, Anglian's distribution network is broken down into distribution zones and district metered areas. A DMS measures flows in to and out of each area and helps to identify where network management and leakage control could be improved.
The implementation of the DMS in this case involved;
- addition of low-power radio (LPR) outstations to log and transmit data from remote locations,
- connection of flowmeters to the regional telemetry system via existing and new outstation installations,
- additional DMS calculation capabilities and changes to the data server to process the data for reporting purposes,
- additional reporting functionality to display data according to the user's requests
- provision of a simple, automated, configuration tool.
Constant monitoring and recording of DMS data provides a fuller understanding of the water distribution network, ultimately resulting in a model which can identify even the smallest leaks.
Flowmeters underpin the DMS and regional telemetry system. The meters may be situated on water sites such as water treatment works, service reservoirs, water towers and water boosters. More often, however, they are located remotely in the distribution network. Three types of meters are used;
- electromagnetic meters - full bore in-line meters which require power. They provide volt-free pulsed outputs with certain versions also providing analogue outputs,
- insertion meters - these use a probe inserted through the wall of the pipe to measure the flow rate. They also require power and provide volt-free pulsed outputs with certain versions also providing analogue outputs.
- mechanical turbine - in-line meters which produce volt-free pulsed outputs and do not require a power supply.
When located on water sites the flowmeter output is hardwired to an existing telemetry outstation by either pulsed or analogue output. Outputs are continuously monitored and 15min total flows are passed to the regional telemetry system via UHF radio, PSTN or leased line as requested by the data gatherer.
Where flowmeters are remotely situated, the equipment may be required to operate from battery power, or an external DC source depending on the availability of mains power. Remote outstations and flowmeters are normally situated in small kiosks.
Logica designed a range of LPR outstations specifically for use in district metering. Although all of the LPR units contain built-in radio modems, each type of unit is used for different purposes for both above and below ground use.
For remote sites where LPR coverage is not possible, the flowmeter pulsed output is connected to a battery powered outstation. These outstations continuously count pulses and 15min total flows are passed to the regional telemetry system via PSTN lines.
Once per day the telemetry data server utilises flow data to calculate the following statistics for flowmeters, distribution zones (DZs) and district metered areas (DMAs);
- net flows,
- daily total flows (the summation of 15min net flow values in a 24hr period),
- minimum night flows (calculated between 00:00 to 07:00hrs on a rolling hourly period).
Logica implemented a web-based reporting tool so, regardless of location, Anglian staff could configure and view these calculations in a graphical format from a workstation. This greatly simplifies the need to understand the complex underlying calculations and makes modifications easy to achieve. A number of standard reports were developed and the system is flexible so new
reports can be generated with minimal development effort. New reports can be rolled-out easily because web technology offers a single point of software upgrade at the server. Reports can be displayed and printed in a number of formats. Fig. 1 shows a typical report of the minimum night flow for Fakenham DZ. Colours show the validity or otherwise of the data presented. The graphical format of the report allows staff to identify easily potential problems. For example, in this report a leak can clearly be seen: the minimum night flow has steadily increased from its typical norm. As a result, the leak was repaired and the report shows the validity of the repair as the minimum night flow has returned to the norm. A range of other reports are available through this web tool, providing detailed leakage information by DZ, DMA or individual meter depending on the particular information required.
The use of browser technology and HTML allows related flow information to be hyperlinked. Related reports for a site and all related flow values are accessible via a single mouse click. Data presented within the reports can be easily copied and pasted into other applications, Microsoft Excel for example, to allow more detailed analysis.
The DMS was designed around 437 DZs, 1,500 DMAs and 2,800 flowmeters. It took four years to implement and roll out. Now the DMS is operational, Anglian and Logica are looking at the next developments for the water companyÕs telemetry system. Work already underway includes the gradual replacement of old outstations with the next generation designs which have high-speed counting capacity. Enhancements are also planned for the DMS to include the night flow minimum alarm limits for all DZs and DMAs, direct e-mails to interested parties when a DZ or DMA falls outside of tolerance and additional reports for Equivalent Service Pipe Bursts (ESPBs).
Anglian Water forms part of the AWG group whose aspiration is to become a leader in the development, creation and management of infrastructure in the UK. The company believes it is this kind of ground-breaking approach to asset management which will enable them to achieve this goal. Logica's aim is to help organisations achieve their business objectives through the innovative use of information technology