Optimising the efficiency of drinking water networks via Topkapi

Collecting flow data in different points distributed strategically in a drinking water distribution network (District Metered Areas, DMA) is the first stake of sectorisation. Automatic real-time analysis of this data using an appropriate tool to produce immediately interpretable indicators was the additional objective set by the Syndicat d’eau du Tregor to the ACTEMIUM ARMOR integrator based in Dinan (22).

Acquisition and processing of time-stamped data at source by Topkapi

Leveraging its experience with Topkapi installed initially in the Pont-Scoul drinking water station, ACTEMIUM ARMOR naturally offered to extend this real-time process supervision to the drinking water network, and hence leak detection monitoring. Beyond native communication with the different remote management controllers or data loggers in the market, one of Topkapi’s benefits for this type of application is its ability to perform calculation operations on historical data.
 
While most SCADA software packages are strictly designed for real-time processing and are unable to merely acquire source time-stamped data, Topkapi can use time-stamped data collected from different RTUs within a same calculation, and process this data (alarm on threshold, trends generation, etc.).
 
Drinking water distribution managed by the Syndicat d’eau du Tregor covers 420 km piping, explains Mr. Koulman MATHIEU, its Director. In a network initially divided into 11 primary sectors, the new equipment installed allowed for finer and more homogenous distribution into 38 DMA points: 16 autonomous loggers (LS42 dataloggers by Sofrel) and 22 RTU controllers (Sofrel S550). Topkapi’s central station is connected to the equipment via GPRS or radio links.

 
Supervision software for a global vision of the network   

"The supervision system was designed to provide synthetic global views of the network with appropriate diagnostic indicators allowing a responsive analysis" explains Mr. MATHIEU. To do this, the calculation functions on sampled data proposed with TOPKAPI’s Report module play their full part. They allow to calculate the following per area:
 

• Daily volume
• Daily flow
• Average hourly flow
• Maximum hourly flow
• Minimum hourly flow
• Overnight flow between 3:00 and 5:00 am
• Linear loss index

The night flow calculation is the first important indicator in leak detection, as it ensures easy spotting of abnormal night flows. Topkapi compares it with an adjustable threshold to generate a visual operator alarm: if the value calculated exceeds the threshold, a “potential leak” alarm is triggered and when it exceeds twice the threshold, it becomes a "positive leak" alarm.
 
The linear loss index expressed in m3/km/d is the second important indicator: it makes a comparison between the subsectors and prioritizes the actions required on the sectors with the highest index.
In addition, delayed summary reports are generated automatically under Excel, providing a global view of all sectors.
 
After a full year of use, the local authority was able to improve its yield by 75% to 79%; i.e. 40,000 m3 water saved. The system also proved that the Syndicate had already reached and exceeded its objective yield set at 67% by Grenelle 2 (for rural burroughs, the minimum mandatory yield set by the authorities is calculated as per the following formula: Rmin=65%+LCI/5, LCI⁽¹⁾ being the Linear Consumption Index). The objective of the Syndicat d'eau du Tregor is now to reach a yield of 85 %, the top threshold set by Grenelle 2.

 
(1) The Linear Consumption Index is calculated as being the average daily volume consumed by users and the needs of the department, plus water sales to other departments expressed in m3 divided by the network linear (connection excluded) expressed in km.