Water Journal : Water Journal April 2012
automation and telemetry technical features 124 APRIL 2012 water The Monitoring Platform The data is hosted on the Gutermann webserver and accessible via log-in to the Zonescan net software. There is mapping, amplitude distribution graphs, frequency spectrum and correlation data in this software platform. Figure 5 shows a map in the Zonescan net software; the green, orange and red dots are the loggers. They are colour-coded green for no leak, orange for possible leak and red for probable leak. The fuzzy orange dot is a correlated leak position. It is also possible to show the loggers in a satellite picture; this provides better orientation. When this particular leak appeared it was identified with correlations from over 15 logger combinations and we repaired the leak in record time, it started on February 9 and was repaired on February 10. We can identify mechanical noises, which reduces the amount of time wasted searching for noises that are not leaks. Figure 6 (top) is the correlation graph and shows the location of noise on the pipeline to identify the leak position with the big peak, which is 22.9 metres from logger 1 and 63.6 metres from logger 2. Figure 6 (bottom) shows the frequency spectrum of the noise detected. False alarms can be created from low frequency noises in the 50 to 150Hz range, while leaks are usually at a higher frequency. All of this analysis is performed in the office before any employee goes out to the site. A leak can be seen in Figure 7; the correlation provided by the Zonescan system was less than half-a-metre from the actual position. Conclusions With this technology we have been able to continue to maintain our MNF to 0.4L/S, with an average run-time of a leak event being 1.5 days, enabling us to reduce our water losses to lower levels than ever before. In addition to this we have reduced the effort and cost of localisation by 98%. With very good maps of the pipeline network the Zonescan produces a precise location of the leak. Considering the excavation cost is €3,000, we still confirm the leak position with a ground microphone before digging. We had no communication problems during a particularly cold winter, with a thick layer of snow on the ground. We found small leaks that our experienced leakage team would not have discovered, and the leak hunters tell me they can hear the worms cough! The Author Frank Tantzky (email: frank.tantzky@ albstadtwerke.de) is Network Operations Manager at Albstadtwerke. The original paper was presented at the Global Leakage Summit, London 2011. This edited version has been prepared by Andrew Clark, who is International sales and marketing director for Gutermann, a company specialising in intelligent leakage management. Since the paper was presented at the Global Leakage Summi, Albstadtwerke has started installing the equipment over the whole of their network. Figure 6. Correlation graph and cross spectrum graph. Figure 7. A leak found by Zonescan.
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