• 상하수도학회지
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• 제21권5호
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• pp.609-619
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• 2007

The objective of this paper is to evaluate the feasibility of conjunctive Operation between Multi-regional water supply networks from multiple source as a effective way to meet two conditions: to minimize the electric cost for providing water demanded and meet the water flow rate for satisfying customers. EPAnet Model is used to calculate a hydraulic water distribution condition based on an integrated operation of water supply systems located in short distance. The modeling was conducted on several simulation cases including the individual operation by existing inter-regional water supply networks within short distance, the conjunctive operation of more than two existing networks with valve fully closed and full open constraint. As a study distribution system, water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. It was found that a well-allocated water supply scheme based on a conjunctive operation promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. The result such as unit district costs, pareto optimum pump combination sets will be applied to the optimization for a conjunctive operation of existing inter-regional water supply networks within short distance.

• 한국수자원학회논문집
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• 제39권1호
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• pp.35-46
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• 2006

본 연구에서는 안전하고 원활한 용수공급을 목적으로 하는 상수도관망시스템의 오염예방 및 위험관리를 위한 통합의사결정시스템의 기본구조를 제시하고 유럽과 미국에서 널리 사용되고 있는 다기준 의사결정기법인 PROMETHEE와 ANP를 적용해 상수도관망의 이상징후 판정을 위한 위험요소들의 우선순위를 평가하였다. 문제 구성을 위하여 pH 잔류염소농도, 유량, 수압, 전기전도도, 탁도, 블록누수량, 수온을 자료항목으로 선정하였고 관부식, 관파열, 관내수질오염을 평가기준으로 하여 PROMETHEE와 ANP의 결과를 비교 분석하였다. 본 연구에서 제시한 상수도관망의 위험요소 평가결과는 위기상황 대처방안시스템 구축시 사고대응 제어알고리즘 설계의 기초자료가 될 수 있을 것이다.

• 상하수도학회지
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• 제27권6호
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• pp.679-687
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• 2013

Although stable and safe drinking water supply to the customers is a basic function of multi-regional water supply systems in Korea, most systems have their vulnerabilities in emergency time due to the branch-type. Application of connections from the other water supply system can provide a solutions for these tentative problems. This paper describes reduction planning of water supply accidents that can minimize a service interruption to customers in multi-regional water supply system by connecting pipe lines between local water supply systems in Mokpo city areas. The result of this study shows that Juam dam multi-regional water supply systems can cover all of the water shortage in southern parts of Jeonnam multi-regional water supply systems by transmitting water through connected pipes between local networks. This can be effective to supply water interactively in various contingencies, when a pipe line accident occurs in southern area of Jeonnam multi-regional water supply systems. On the contrary, southern area of Jeonnam multi-regional water supply systems can cover 99.5 %($62,500m^3/day$) of the water shortage of Juam dam multi-regional water supply systems when service interruptions caused by various pipe accidents occur in the system.

• 한국수자원학회논문집
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• 제46권7호
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• pp.745-754
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• 2013

수돗물의 생산 및 공급과정에 소요되는 에너지에 대한 체계적인 분석 및 평가는 최근의 전력부족 사태와 온실가스 감축의 필요성에 따라 관심이 증가되고 있다. 본 연구에서는 기존의 연구에서 제시한 결과에 대한 검토를 통하여 실용적으로 적용 가능한 에너지 분석기법 및 평가기법을 제시하였다. 본 연구에서는 EPANET2의 수리해석 결과를 이용하여 에너지를 평가할 수 있는 모형을 MATLAB 플랫폼 기반 하에서 개발하였다. 제안된 기법은 상수관망의 입지, 관로의 상태, 누수정도 등에 따라 시설물이 내재적으로 가지는 에너지관리 효율과 운영 효율을 분리하여 평가할 수 있는 성능평가 지표를 제시하였다. 개발모형은 시험관망과 실제관망에 대하여 각각의 상수관망 구성요소에 대한 에너지 분석 및 평가결과를 제시함으로써 적용성 평가를 실시하였다. 본 연구의 결과는 상수관망 에너지관리의 최적화를 도모함으로써 피크시간대의 전력수요 관리 및 에너지 절감형 상수도 시스템 계획 및 운영에 활용될 수 있을 것으로 기대된다.

• 한국수자원학회논문집
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• 제50권7호
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• pp.441-453
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• 2017

상수관망 시스템은 다수의 이용자에게 용수를 공급하기 위한 사회기반시설물로써, 적절한 수압을 유지하고 안정적으로 용수를 공급할 수 있어야 한다. 따라서 안정적인 설계와 효율적인 운영을 위해서는 상수관망 시스템의 용수 공급능력을 정량적으로 파악하는 것이 중요하다. 이러한 노력의 일환으로 상수관망 시스템 내 에너지 거동을 통해 신뢰도를 정량화한 신뢰도 지수가 다양한 방법으로 개발되어 왔다. 대부분의 신뢰도 지수는 공통적으로 절점에서의 최소요구수두 및 초과수두의 형태로 공급된 에너지를 기반으로 산정되며, 일부 지수의 경우 상수관망에 공급된 총 에너지 또는 용수 공급과정에서 손실된 에너지를 추가적으로 고려하여 산정된다. 본 연구에서는 상수관망의 용수 공급 과정에 따른 에너지 구성 요소를 소개하였으며 기존에 개발된 몇 가지 신뢰도 지수를 대상으로, 상수관망의 공급부하 상황을 고려한 시나리오 분석을 통해 신뢰도 지수의 적용성을 알아보고자 하였다. 또한, 각 절점 별 지수값을 도시함으로써, 상수관망 내 신뢰도의 공간적 분포를 나타내어 분석함으로써 보다 확장된 시스템 신뢰도 지수의 활용방안을 제시하였다.

• 한국주거학회논문집
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• 제13권6호
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• pp.89-99
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• 2002

The purpose of this research is to analyze the characteristics of flow rate distribution in hot-water piping networks in the apartment building. A 14-story apartment house was selected as a sample building and analyzed numerically by Hardy-Cross method. Two different piping networks, one has three vertical zones and the other of a single zone with automatic balancing valves, were compared. Some of research results are as follows; As the temperature of supply hot-water increases, the flow rate of it does by buoyancy effect, but this effect is not found in the piping network with automatic balancing valves. Non-uniformity in hot-water flow distributions to all stories in the piping system of single vertical zone can be completely reformed by the installation of either manually operated or automatic balancing valves in every story.

• 상하수도학회지
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• 제29권3호
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• pp.293-303
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• 2015

Optimal design of the water supply pipe network aims to minimize construction cost while satisfying the required hydraulic constraints such as the minimum and maximum pressures, and velocity. Since considering one single design factor (i.e., cost) is very vulnerable for including future conditions and cannot satisfy operator's needs, various design factors should be considered. Hence, this study presents three kinds of design factors (i.e., minimizing construction cost, maximizing reliability, and surplus head) to perform multi-objective optimization design. Harmony Search (HS) Algorithm is used as an optimization technique. As well-known benchmark networks, Hanoi network and Gyeonggi-do P city real world network are used to verify the applicability of the proposed model. In addition, the proposed multi-objective model is also applied to a real water distribution networks and the optimization results were statistically analyzed. The results of the optimal design for the benchmark and real networks indicated much better performance compared to those of existing designs and the other approach (i.e., Genetic Algorithm) in terms of cost and reliability, cost, and surplus head. As a result, this study is expected to contribute for the efficient design of water distribution networks.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.500-504
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• 2008

The objective of this paper is to evaluate the feasibility of using an optimization model as a effective way to search conjunctive operation scheme to meet two conditions; one is to minimize the electric cost for pumping and another is to meet the water demand for satisfying customers. The feasibility is confirmed as comparing the best combinations of pumps between multi-regional water supply networks from multiple sources which are obtained through an optimization modeling and EPAnet modeling. KModsim model, a network optimization model, was used to determine conjunctive operation scheme in the pipe system. KModsim, based on Lagrangian Relaxation algorithm, is useful for modeling network system and obtaining simultaneously pump combination and water allocation with given input option such as energy unit cost supplying from a source into a consumer, operating pumping combination. This study develops the procedure of determining optimal conjunctive operation scheme with using KModsim model. As a study region, the water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. The EPAnet hydraulic simulation result(Ryu et al, 2007, KSWW) gave input data for optimization model; energy unit price(won/$m^3$), water service available area etc.. It was assured that the combination of pump operation through optimum conjunctive operation is to be optimum scheme to obtain the best economic water allocation with comparison to the hydraulic simulation result such as electric cost and pump combination cases. The results obtained through the study are as follows. First, It was found that a well-allocated water supply scheme, the best combination of pump operation through optimum joint operation, promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. Second, an application of KModSim, a network model, gave the amount of water allocation from each source to a consumer with consideration of economic supply. Finally, in a service area available to supply through conjunctive operation of existing inter-regional water supply networks within short distance, a conjunctive operation is useful for determining each transmission pipeline's service area and maximizing the effectiveness of optimizations in pumping operation time.

• 상하수도학회지
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• 제31권5호
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• pp.421-430
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• 2017

In this study, a model was developed to predict for Disinfection By-Products (DBPs) generated in water supply networks and consumer premises, before and after the introduction of advanced water purification facilities. Based on two-way ANOVA, which was carried out to statistically verify the water quality difference in the water supply network according to introduce the advanced water treatment process. The water quality before and after advanced water purification was shown to have a statistically significant difference. A multiple regression model was developed to predict the concentration of DBPs in consumer premises before and after the introduction of advanced water purification facilities. The prediction model developed for the concentration of DBPs accurately simulated the actual measurements, as its coefficients of correlation with the actual measurements were all 0.88 or higher. In addition, the prediction for the period not used in the model development to verify the developed model also showed coefficients of correlation with the actual measurements of 0.96 or higher. As the prediction model developed in this study has an advantage in that the variables that compose the model are relatively simple when compared with those of models developed in previous studies, it is considered highly usable for further study and field application. The methodology proposed in this study and the study findings can be used to meet the level of consumer requirement related to DBPs and to analyze and set the service level when establishing a master plan for development of water supply, and a water supply facility asset management plan.

• 상하수도학회지
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• 제26권2호
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• pp.249-256
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• 2012

The paper describes a design methodology that can select a proper reliability factor and apply the selected reliability factor into the real water distribution system. Reliability factors which are used for the assesment of water supply networks, can be categorized by a connectivity, a reachability, an expected shortage and an availability. Among these factors, an expected shortage is the most proper reliability factor in the aspect of economic evaluation. Therefore, the expected shortage is applied to draw a water supply reliability into Changwon water supply systems. And the economic pipe diameter can be determined as 600mm for a connection pipe in the pipe network from the estimation of the expected shortage. Also, a quantitative effect of the connection pipe can be expressed in terms of the reduction, which is estimated by the expected shortage of 30,269$m^{3}$ from 68,705$m^{3}$ at initial condition to 38,436$m^{3}$ under the connected condition with the diameter 600mm pipe.