• 상하수도학회지
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• 제27권1호
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• pp.129-138
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• 2013

Water interruption is often caused by a rupture in the branch-like singular pipeline. This will cause critical complaints from household and may decrease public service quality. As an alternative of singular pipeline, additional parallel pipeline could be installed for sustainable water supply. This system is called double pipeline system and able to be utilized for water transmission line between treatment plant and distribution reservoir. Construction of double pipeline was thought to increase capital cost, which can be an issue to waterworks authorities. Reducing capital cost was possible by means of installing connectors between two parallel pipelines because of reduced diameter of each pipe. To obtain optimal design condition for connectors, it was necessary to compare water pressure according to accident location, to investigate flow according to connection pipe spacing, connection pipe diameter, and aging of pipe. Reliable and economical connection layouts were determined based on these results. The cost estimation for each design condition was carried out. Cost was approximately reduced by 20 ~ 30 % compared to the double pipeline without connections. In addition to this, connection between double pipelines could expect extra benefits for maintenance since the pipe could be repaired and rehabilitated without interruption.

• 상하수도학회지
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• 제27권3호
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• pp.395-404
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• 2013

The risk of pipe-bursting in multi-regional transmission mains consisting of 89 % of singled pipeline is so high that pipeline stabilization project is required such as renewal and replacement, pipe paralleling, emergency ties. Pipeline stabilization projects could be postponed at the step of initial decision-making because effect of this project is intangible benefit like activation of economic, improvement of welfare related to water. This study is to suggest quantified economical feasibility model for intangible benefit presumption to solve above problem. Cost reduction of emergency water supply, leakage, burst restore and energy efficiency improvement was altered and applied. As a result of economic analysis taking into account estimated benefit and cost under discount rate 5.5 %, service life 40 years, sufficient economic feasibility analyzed with B/C 2.45, NPV 317,700 million won, IRR 9.09 %.

• Structural Engineering and Mechanics
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• 제73권3호
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• pp.339-351
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• 2020

Earthquakes are natural disasters that cause serious social disruptions and economic losses. In particular, they have a significant impact on critical lifeline infrastructure such as urban water transmission networks. Therefore, it is important to predict network performance and provide an alternative that minimizes the damage by considering the factors affecting lifeline structures. This paper proposes a probabilistic reliability approach for post-hazard flow analysis of a water transmission network according to earthquake magnitude, pipeline deterioration, and interdependency between pumping plants and 154 kV substations. The model is composed of the following three phases: (1) generation of input ground motion considering spatial correlation, (2) updating the revised nodal demands, and (3) calculation of available nodal demands. Accordingly, a computer code was developed to perform the hydraulic analysis and numerical modelling of water facilities. For numerical simulation, an actual water transmission network was considered and the epicenter was determined from historical earthquake data. To evaluate the network performance, flow-based performance indicators such as system serviceability, nodal serviceability, and mean normal status rate were introduced. The results from the proposed approach quantitatively show that the water network is significantly affected by not only the magnitude of the earthquake but the interdependency and pipeline deterioration.

• 상하수도학회지
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• 제30권6호
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• pp.725-736
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• 2016

There is a growing concern on the improvement of water distribution pipeline for multi-regional water supply system in Korea along with its aging infrastructure. Rehabilitation of large diameter pipeline is more efficient in cost and time compared to replacement with trenching. The procedure for rehabilitation are diagnosis, cleaning, spraying coating material, and final inspection. The internal state of pipeline was carefully diagnosed and got C grade, which required rehabilitation. We found that 17,274,787,000 Korean won could be saved after pipe surface coating because of increased C coefficient of Hazen-Williams equation. Optimal coating material was D polyurea. We also found optimal distance between spraying nozzle and pipe wall to be 70 - 80 cm, which were critical factors for coating quality. This study also illustrated the time for spray drying to be more than 30 min. These results could be used in the quality control process during rehabilitation of aged pipelines.

• 전기학회논문지
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• 제57권10호
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• pp.1720-1725
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• 2008

Because of the continuous increasing of energy consumption, metallic pipelines are widely used to supply services to customers such as gas, oil, water, etc. Most common metallic pipelines are underground and are now frequently being installed in nearby electric power lines. In recent years, buried gas pipeline close to power lines can be subjected to hazardous induction effects, especially during single line to ground faults. because it can cause corrosion and it poses a threat to the safety of workers responsible for maintenance. Accordingly, it is necessary to take into consideration for analysis of induced voltage on gas pipelines in transmission lines. This paper analyzed the induced voltage on the gas pipelines due to the 154kV transmission lines in normal case and in different faulty case conditions using EMTP (Electro-Magnetic Transients Program).

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.199.1-199.1
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• 2010

Use of recycled aggregates that are constituents of concrete or asphalt-based structures has become popular because the recycling is an eco-friendly way to overcome the depletion of natural aggregates. In order to adopt the recycled aggregates for backfilling a power transmission pipeline trench, their thermal resistivity should be low enough to prevent thermal runaway in the transmission system. In this study, a series of laboratory tests with QTM-500 and KD2 Pro was performed to measure the thermal resistivity of recycled aggregates prepared from various sources. Relationships between the thermal resistivity of recycled aggregates and the water content have been obtained with consideration of compaction effort. Similar to natural soils, the thermal resistivity of the recycled aggregates decreases with increasing the water content. In addition, this study compared the experimental data with conventional prediction models for the thermal resistivity in the literature, which suggests the availability of the recycled aggregates as backfill material substituting for natural aggregates when backfilling the power transmission pipeline trench.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1231-1238
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• 2010

Recently, the utilization of recycled aggregates for backfilling a power transmission pipeline trench has been increasing due to the issues of eco-friendly construction and shortage of natural aggregate resource. It is important to investigate the physical and thermal properties of the recycled aggregates that can be used as a backfill material. This study presents the thermal properties of two types of recycled aggregates with various particle size distributions. The thermal properties of the recycled aggregate were measured using the transient hot wire method and the probe method after performing the standard compaction test using an automatic compactor. Similar to silica sand, the thermal resistivity of the recycled aggregates decreased when the water content increased. This study shows that the recycled aggregate can be a promising backfill material substituting for natural aggregate when backfilling the power transmission pipeline trench.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2009년도 춘계학술발표회
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• pp.177-178
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• 2009

관로내의 유속이 급격히 변하면 압력도 크게 상승하거나 강하하게 되어 유체 과도현상을 일으키게 된다. 이러한 수격현상에 대한 연구는 펌프스테이션이 커지고 유체를 이송하는 시스템이 대형화되어 그 중요성이 더욱 증가하였다. 이것은 파이프라인이 길어지고 복잡해지기 때문이다. 이 연구에서는 특성법을 이용하여 대형펌프 시스템의 밸브 개폐로 발생하는 수격현상을 평가하였다.

• 한국유체기계학회 논문집
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• 제14권5호
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• pp.39-47
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• 2011

Flow control range of valve, which is installed on pipeline, varies according to valve type, pipe diameter, pipe length, roughness, and elevation difference of both ends of pipeline. A lot of computation efforts and knowledge are needed to estimate flow control range of valve, considering above many parameters. The table of flow control range of each valve type is presented for convenience of pipeline design engineers who must make decision of valve size and type in this study. Also the reason that butterfly valve is recommended for flow control, and gate valve is forbidden is presented via quantification and figures in this study.

• Current Optics and Photonics
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• 제7권5호
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• pp.511-517
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• 2023

Pipelines play an important role in urban water supply and drainage, oil and gas transmission, etc. This paper presents a technique for pattern recognition of fiber optic vibration signals collected by a distributed vibration sensing (DVS) system using a deep learning residual network (ResNet). The optical fiber is laid on the pipeline, and the signal is collected by the DVS system and converted into a 64 × 64 single-channel grayscale image. The grayscale image is input into the ResNet to extract features, and finally the K-nearest-neighbors (KNN) algorithm is used to achieve the classification and recognition of pipeline damage.