• 전기학회논문지
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• 제61권9호
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.378-379
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• 2012

현재 에너지 소비가 증가하면서 환경적인 이슈로 전력 산업의 고도화 및 에너지 효율화에 대한 요구가 증가함에 따라 지능형 전력시스템과 같은 전력 IT 산업이 신 성장 동력으로 주목받고 있다. 지능형 전력 시스템을 통해 전력 수요에 따른 공급의 밸런스를 최적화하게 되면 에너지 수입 및 전력 인프라 건설, 운영에 소요되는 막대한 비용을 절감할 수 있고, 안정적으로 전력을 공급할 수 있게 된다. 하지만, 모든 설비 및 장비를 실시간 관리하기 위해서는 인력낭비가 발생할 뿐만 아니라, 응급 상황을 인지하지 못해 전력사고로 이어지는 문제가 발생할 수 있다. 따라서, 본 논문에서는 스마트폰 기반의 원격 제어 및 모니터링 기능을 구비한 지능형 수배전반 통합관리 시스템을 개발하였다. 기존의 수배전반 관리 시스템의 단점을 보완한 본 시스템은 저비용으로 효율성과 안정성을 대폭 향상 시킬 수 있어, 향후 전력 IT 산업의 발전에 크게 도모할 수 있을 것으로 판단된다.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.415-422
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• 2014

This paper presents a new approach to solve the multi area unit commitment problem (MAUCP) using an evolutionary programming based particle swarm optimization (EPPSO) method. The objective of this paper is to determine the optimal or near optimal commitment schedule for generating units located in multiple areas that are interconnected via tie lines. The evolutionary programming based particle swarm optimization method is used to solve multi area unit commitment problem, allocated generation for each area and find the operating cost of generation for each hour. Joint operation of generation resources can result in significant operational cost savings. Power transfer between the areas through the tie lines depends upon the operating cost of generation at each hour and tie line transfer limits. Case study of four areas with different load pattern each containing 7 units (NTPS) and 26 units connected via tie lines have been taken for analysis. Numerical results showed comparing the operating cost using evolutionary programming-based particle swarm optimization method with conventional dynamic programming (DP), evolutionary programming (EP), and particle swarm optimization (PSO) method. Experimental results show that the application of this evolutionary programming based particle swarm optimization method has the potential to solve multi area unit commitment problem with lesser computation time.

• Journal of Power Electronics
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• 제12권1호
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• pp.215-222
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• 2012

Lighting represents a significant component of commercial buildings, particularly office buildings. Fluorescent lighting is invariably used in all commercial, industrial and residential areas. A significant amount of lighting energy is wasted every day by leaving the lights on and not utilizing daylight energy. However, if daylight illuminance can be harnessed, this will reduce the electricity consumption of fluorescent lamps and save energy. This paper explains possible significant savings in lighting energy consumption and hence in costs, without reducing the performance and visual satisfaction in office or industrial buildings. It is proposed to obtain energy saving by reducing the supply voltage without degradation in lighting performance. Experimental results confirm that as much as 20% of electrical energy can be saved by reducing about 9% of the supply voltage, without noticeably affecting light output while complying with lighting standard limits.

• Journal of Biosystems Engineering
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• 제26권2호
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• pp.93-104
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• 2001

A linear chemigation system, integrating agrichemical appication units of pesticide and fertilizer into an irrigation system, was selected as a suitable model for the cost savings in farm management and automation. Technical designs were conducted in the areas of structure, power, drive, control, and hydraulic systems. An experimental farm was sectioned into the fields of 40m by 200m and systemized with the linear-move chemigation system of 36m in span. The chemigation system consisted of a base unit monitoring and controlling overall operation, and a driving unit traveling linearly and injecting agrichemicals. Monitoring and interlocking systems were utilized against unexpected malfunctions of power, injection and drive systems using radio freuency modems between the units. The system can be also modified to various farm sizes and stationary systems of indoor and outdoor.

• 한국생산제조학회지
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• 제22권6호
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• pp.945-949
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• 2013

By using information about specific road grades, one can predict the power required by a vehicle. The prediction of the required power enables the driver to choose the driving route with the best fuel economy, which results in cost and energy savings. A clinometer is one of the more simple tools used to measure road grades, but requires significant time and effort. In this paper, a new method for measuring road grades from within a vehicle is proposed and experimentally verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.27-29
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• 1994

Recently, the energy situation in Korea has been significantly changed. Rapid increase in electricity demand, tremendous financial need for new power plant construction, and environmental problem have led to search for more efficient energy production and energy conservation technologies. Due to the potential energy and cost savings to both electric utilities and industries, cogeneration will play an important role in the electric power and thermal energy supply in the future. In this study, we present the COGENMASTER computer model for optimal system configuration and economic analysis of cogeneration system. We also present several case studies with this module to analyze Korean cogeneration market. The result of this study will be useful to utility and industrial cogeneration planners for rapid analysis of cogeneration's value under a broad range of scenarios.

• 유공압시스템학회논문집
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• 제5권3호
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• pp.15-22
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• 2008

The road simulators have become common tools within the automotive industry for evaluation of vehicle and vehicle system durability performance. These simulators need appropriate input signal generation algorithms to realize the actual driving conditions due to non-linear vehicle and test rig behaviour. Although somewhat unconventional from a control standpoint, the iteration approach has proven to be a very effective method for control of complex, multiple degree-of-freedom systems where the tracking parameter is known a priori. In this paper, the road profile replication algorithm is verified by applying Belgian road to the developed road simulator. The simulation and experimental results are included to evaluate the performance of this simulator. This road simulator provides considerable savings in cost, development time, and testing risk during developing automotive components.

• KIEAE Journal
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• 제15권6호
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• pp.5-10
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• 2015

Purpose: To evaluate the economic performance of grid-connected photovoltaic system in residential house, household electricity bill policy of Korea Electric Power Corporation (KEPCO) must be applied precisely, and market tendency and uncertainty of system also need to be considered. In this study, to evaluate the economic feasibility of PV system, we measured PV power generation and electricity consumption of six of Green home in Daejeon through web based remote monitoring system. Method: We applied Monte-Carlo simulation based on life cycle cost analysis, to reflect an uncertainty of main factor in economic feasibility evaluation of photovoltaic system. Result: First, with deterministic analysis, the difference of NPV of cumulative financial savings among households varied from -3,310 ~ 24,170 thousand won, portraying notably big range. Also the possibility of getting the same result was 50% when applying uncertainty. Second, the higher electricity consumption is, the more economic feasibility of photovoltaic system increases because KEPCO uses progressive taxation in household electricity bill policy. Third, The contribution to variance of electricity price increases in NPV varied from 98.5% to 99.9%. While the inflation rate and annual degradation contributed very little to none.

• 전기학회논문지
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• 제63권1호
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• pp.27-34
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• 2014

The paper proposed a sizing method of an energy storage system(ESS) for peak shaving of high-speed railway substations based on load profile patterns of substations. A lithium based battery ESS was selected since it can produce high-power at high speed that peak shaving requires, and also takes up a relatively smaller space for installation. Adequate size of the ESS, minimum capacity which can technically meet a peak shaving target, was determined by collectively considering load patterns of a target substation, characteristics of the ESS to be installed, and optimal scheduling of the ESS. In case study, a local substation was considered to demonstrate the proposed sizing method. Also economic analysis with the determined size of ESS was performed to calculate electricity cost savings of the peak shaving ESS, and to offer pay-back period and return on investment.