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공명식 ( Myeong Sik Kong ),이현동 ( Hyun Dong Lee ),강성원 ( Sung Won Kang ),이준형 ( Joon Hyung Lee ) 한국수처리학회 2013 한국수처리학회지 Vol.21 No.5
The Revenue Water(RW) rate, used for a performance assessment and a performance improvement in Korea, was calculated through top-down analysis. However, Some problems that RW rate lack credibility have been pointed out as a performance indicator. Therefore, the relationship among the RW rate, Non-Revenue Water(NRW) and the system input volume were analyzed. The results of this study showed that the RW rate varied with system input volume even if the NRW has a certain value. Furthermore, the relationship between the RW rate and real loss, using performance improvement, could not be identified. Based from the results of this study, the necessity on the application of a new performance indicator was confirmed. Moreover, the Infrastructure Leakage Index (ILI), RW rate and NRW rate were analyzed in this study. It was observed that there was a high correlation between the ILI and real loss(R2=0.9185), and NRW(R2=0.8069) represents the condition of the water supply system. Therefore, ILI was chosen as performance assessment indicator to represent the exact water loss in the water supply system.
공명식 ( Myeong Sik Kong ),이현동 ( Hyun Dong Lee ),강성원 ( Sung Won Kang ),박은주 ( Eun Zoo Park ) 한국수처리학회 2013 한국수처리학회지 Vol.21 No.4
Characteristics of leak noise frequency was built through comparison analysis of collected acoustic signals from pipeline before and after leakage. Leakage was identified at 10 points, acoustic signals were collected at 14 water supply facilities(manhole, water valve, stop valve). Investigation time was set up from 11 PM to 5 AM in order to minimize effect of white noise caused by water usage, vehicle traffic, etc. Comparing results from characteristics of acoustic signals before and after leakage showed that signal strength became weaker after repaired pipeline from the full range of frequency bands, except for some uncertain data that include heavy noise. Frequency bands indicating strong signal strength were from 200 to 2,000 ㎐, with or without leakage. As a result of analysis based on pipe material, leakage-related frequency bands were identified from 300 to 2,000 ㎐ in case of galvanized steel pipe. On the other hand, frequency bands were related less than 1,200 ㎐ if leak occurred in stainless steel pipe. Frequency analysis result according to leak point, leak noise were related from 500 to 2,000 ㎐ in case of a leak in a straight pipe, frequency bands of leak noise in joints and junction had relevance to the range of 300 to 1,200 ㎐.