• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.225-230
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• 2004

Leak noise is a good source to identify the exact location of a leak point of underground water pipelines. Water leak generates broadband noise from a leak location and can be propagated to both directions of water pipes. However, the necessity of long-range detect ion of this leak location makes to identify low-frequency acoustic waves rather than high frequency ones. Acoustic wave propagation coupled with surrounding boundaries including cast iron pipes is theoretical analyzed and the wave velocity was confirmed with experiment The leak locations were identified both by the acoustic emission (AE) method and the cross-correlation method. In a short-range distance, both the AE method and cross-correlation method are effective to detect leak position. However, the detect ion for a long-range distance required a lower frequency range accelerometers only because higher frequency waves were attenuated very quickly with the increase of propagation paths. Two algorithms for the cross-correlation function were suggested and a long-range detection has been achieved at real underground water pipelines longer than 300m.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.415-425
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• 2015

Aging water pipe networks hinder efficient management of important water service indices such as revenue water and leakage ratio due to pipe breakage and malfunctioning of pipe appurtenance. In order to control leakage in water pipe networks, various methods such as the minimum night flow analysis and sound waves method have been used. However, the accuracy and efficiency of detecting water leak by these methods need to be improved due to the increase of water consumption at night. In this study the Principal Component Analysis (PCA) technique was applied to the night water flow data of 426 days collected from a water distribution system in the interval of one hour. Based on the PCA technique, computational algorithms were developed to narrow the time windows for efficient execution of leak detection job. The algorithms were programmed on computer using the MATLAB. The presented techniques are expected to contribute to the efficient management of water pipe networks by providing more effective time windows for the detection of the anomaly of pipe network such as leak or abnormal demand.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.281-282
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.873-878
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• 2000

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.227-236
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• 2003

Leaks in underground pipelines can cause social, environmental and economical problems. One of relevant countermeasures against leaks is to find and repair of leak points of the pipes. Leak noise is a good source to identify the location of leak points of the pipelines. Although there have been several methods to detect the leak location with leak noise, such as listening rods, hydrophones or ground microphones, they have not been so efficient tools. In this paper, acoustic emission (AE) sensors and accelermeters are used to detect leak locations which could provide all easier and move efficient method. Filtering, signal processing and algorithm of raw input data from sensors for the detection of leak location are described. A 120m-long pipeline system for experiment is installed and the results with the system show that the algorithm with the AE sensors and accelerometers offers accurate pinpointing of leaks. Theoretical analysis of sound wave propagation speed of water in underground pipes, which is critically important in leak locating, is also described.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.5
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• pp.459-469
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• 2017

A real scale leakage test facility was developed to study the leak signal characteristics of water supply pipelines, and then leak tests were carried out. The facility was designed to overcome the limited experimental circumstances of domestic water supply pipeline experimental facilities. The length of the pipeline, which was installed as a straight line, is 280m. Six pipes were installed on a 70m interval with different pipe material and diameters that are DCIP(D200, D150, D100, D80), PE(D75) and PVC(D75).The intensity of the leakage is adjusted by changing the size of the leak hole and the opening rate of ball valve. Various pressure conditions were simulated using a pressure reducing valve.To minimize external noise sources which, deteriorate the quality of measured leak signal, the facility was built at a quiet area, where traffic and water consumption by customers is relatively rare. In addition, the usage of electric equipment was minimized to block out noise and the facility was operated using manual mode. From the experimental results of measured leakage signal at the facility, it was found that the signal intensity weakened and the signal of high frequency band attenuated as the distance from the water leakage point increased.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.169-173
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• 1998

The practice of the construction and management of the underground petroleum storage facilities in Korea was investigated extensively, and the problems were identified. The advanced technologies in the U.S.A was comparatively studied. Considering the effectiveness of leak prevention and technology applicability, the following measures were suggested. To prevent corrosion of the tank, a clad tank, an interior-lining tank, or a double-wall tank was appropriate and appeared to be most cost effective. For piping, non-metalic material was suggested. To prevent spill, a catchment basin can be effective. For monitoring of leak, construction of more than one of one or combination of an automatic leak-detection device, a vapor-detection system, a ground water-monitoring system, and a double-wall detection system was recommended.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.31-32
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• 2018

상수도배관에 누수발생시 주변의 다른 주요 기반시설들에 피해를 줄 수 있어 상수도배관의 누수감지 시스템 개발이 필요하다. 본 논문에서는 상수도배관의 누수감지를 위해 음향방출 센서와 기계학습 알고리즘을 적용한 누수검출 알고리즘을 제안하였으며 모의실험결과 누수 전/후의 상태를 100% 검출하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.160-160
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• 2019

Water is a limited source that needs to be properly managed and distributed to the ever-growing population of the world. Rapid urbanization and development have increased the overall water demand of the world drastically. However, there is loss of billions of liters of water every year due to leakages in water distribution systems. Such water loss means significant financial loss for the utilities as well. World bank estimates a loss of $14 billion annually from wasted water. To address these issues and for the development of efficient and reliable leakage management techniques, high efforts have been made by the researchers and engineers. Over the past decade, various techniques and technologies have been developed for leakage management and leak detection. These include ideas such as pressure management in water distribution networks, use of Advanced Metering Infrastructure, use of machine learning algorithms, etc. For leakage detection, techniques such as acoustic technique, and in recent yeats transient test-based techniques have become popular. Smart Water Grid uses two-way real time network monitoring by utilizing sensors and devices in the water distribution system. Hence, valuable real time data of the water distribution network can be collected. Best results and outcomes may be produced by proper utilization of the collected data in unison with advanced detection and management techniques. Long term reduction in Non Revenue Water can be achieved by detecting, localizing and repairing leakages as quickly and as efficiently as possible. However, there are still numerous challenges to be met and future research works to be conducted in this field.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1829-1835
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• 2000

The experimental results of sodium-water reaction noise measurement in frequency range $1{/sim}200kHz$ are presented. The experiments of noise generation under the condition of sodium test facility, water leak rate $0.01{\sim}1.2g/s$ and temperature of sodium $250{\sim}500^{\circ}C$, were carried out. From theoretical study it is noted that the noise resonant attenuation on hydrogen bubbles in liquid sodium plays the significant role for leak noise spectra formation. Interaction of leak noise and hydrogen bubbles in sodium being accompanied by thermal, emission and viscosity energy dissipation was studied. Acoustic noise spectra were investigated from point of view of water leak detection in sodium/water steam generator. The results of sodium-water reaction noise absorption on hydrogen bubbles in liquid sodium by temperature $250{\sim}500^{\circ}C$ are presented. The theoretical model of noise absorption using the coefficients of attenuation was developed. From calculation the coefficients of attenuation were estimated.