• 한국정보통신학회논문지
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• 제17권7호
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• pp.1660-1671
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• 2013

본 논문에서는 빛 에너지 하베스팅 자가발전 시스템을 위한 두 가지 구조의 전력관리 회로를 제안한다. 첫 번째는, 솔라셀이 부하가 동작할 수 있는 충분한 전압을 출력하는 경우, 전력관리회로를 통해 직접 솔라셀의 에너지를 부하로 공급하는 구조이다. 두 번째는 초소형 솔라셀이나 집적화된 솔라셀에서처럼 출력전압이 0.5V 이하로 매우 작아서 부하를 직접 구동할 수 없는 경우, 전압부스터를 사용하여 충분한 전압까지 승압한 후, 이를 전력관리회로를 통해 부하로 공급하는 구조이다. 이 두 가지 구조의 전력관리 회로는 $0.18{\mu}m$ CMOS 공정으로 설계 및 제작되었으며, 측정을 통해 성능을 비교 분석하였다.

• 농촌계획
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• 제24권4호
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• pp.99-119
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• 2018

Unit load factor, which is used for the quantification of non-point pollution in watersheds, has the limitation that it does not reflect spatial characteristics of soil, topography and temporal change due to the interannual or seasonal variability of precipitation. Therefore, we developed the method to estimate a watershed-scale non-point pollutant load using seasonal forecast data that forecast changes of precipitation up to 6 months from present time for watershed-scale water quality management. To establish a preemptive countermeasure against non-point pollution sources, it is possible to consider the unstructured management plan which is possible over several months timescale. Notably, it is possible to apply various management methods such as control of sowing and irrigation timing, control of irrigation through water management, and control of fertilizer through fertilization management. In this study, APEX-Paddy model, which can consider the farming method in field scale, was applied to evaluate the applicability of seasonal forecast data. It was confirmed that the rainfall amount during the growing season is an essential factor in the non-point pollution pollutant load. The APEX-Paddy model for quantifying non-point pollution according to various farming methods in paddy fields simulated similarly the annual variation tendency of TN and TP pollutant loads in rice paddies but showed a tendency to underestimate load quantitatively.

• 한국물환경학회지
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• 제39권5호
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• pp.377-389
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• 2023

Chungcheongnam-do has been measuring the flow rate and water quality of streams in the province once a month since 2011 in order to water environment policies. Based on the results, after evaluating the coefficient of variation and the tendency of the water quality trend by using the Mann-Kendall test and Sen's Slope for each stream, the streams subject to priority introduction of Total Pollution Load Management at Tributaries were selected through the Stream Grouping Method. The water quality trend analysis results for 125 streams using the Mann-Kendall test and Sen's Slope were evaluated as streams showing a tendency of deteriorating water quality Biochemical oxygen demand (BOD): 13 streams, Total Phosphorus (T-P): 16 streams). Streams with deteriorating water quality were classified into A-D groups using the Stream Grouping Method. Group A, which has a high flow rate and high water quality, is a stream that requires priority management, and was selected as a stream for introduction of Total Pollution Load Management at Tributaries. There are 7 streams that need to be introduced into the BOD category, and there are 7 streams that need to be introduced into the T-P category. In this study, based on flow and water quality monitoring data accumulated over a long period of time (2011-2022), statistical techniques are used to select watersheds in which water quality is deteriorating. Accordingly, it is expected that it will be useful in establishing a water quality improvement plan in the future.

• 대한환경공학회지
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• 제36권5호
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• pp.367-377
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• 2014

국내 최대 상수원인 팔당호는 하천형 호소로 분류되며, 팔당호 수질은 외부오염원의 영향이 크다. 이에 본 연구에서는 팔당호 상류지역의 오염원 분포와 오염물질 유출특성을 분석하여 BOD와 TP 관리를 위한 중점관리 오염원을 선정하고자 하였다. 이를 위해 11개 단위유역에 대한 오염원별 발생부하량과 배출부하량을 조사하고, 74개 소하천의 수질 유량 측정결과를 이용하여 유달부하량과 유역면적당 유달부하 밀도를 분석하였다. 오염원별 BOD, TP 발생부하량과 배출부하량, 유달부하량을 분석한 결과, BOD 발생부하량은 축산계가 66.0%로 가장 높은 비율을 차지하였고, BOD 배출부하량은 생활계가 42.7%를 차지하였으며, BOD 유달부하량은 축산계와 생활계가 각각 36.4%, 34.3%를 차지하는 것으로 나타났다. TP 발생부하량과 배출부하량, 유달부하량 모두 축산계에서 가장 높은 비율을 차지하였으며, 각각 82.5%, 44.4%, 46.7%로 나타났다. 또한 BOD 유달부하밀도는 인구밀도가 높은 경안천 유역이 $14.6kg/km^2/d$으로 가장 높았고, TP 유달부하밀도는 가축사육두수가 많은 청미천 유역이 $1.23kg/km^2/d$이 가장 높게 나타났다. 이러한 연구결과를 통해 팔당호 수질개선을 위해서는 생활오수와 가축분뇨를 중심으로 오염원관리가 필요하며 경안천 유역은 생활오수에 대한 관리가 필요하고 남한강 유역, 특히 청미천 유역은 가축분뇨에 대한 관리가 필요한 것으로 판단되었다.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.511-517
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• 2015

Determination of the required reserve capacity has an important function in operation of power system and it is calculated based on the largest loss of supply. However, conventional method cannot be applied in future power system, because potential grid-connected distributed generator and abnormal temperature cause the large load imbalance. Therefore this paper address new framework for determining the optimal required reserve capacity taking into account the real time load imbalance. At first, we introduce the way of operating reserve resources which are the secondary, tertiary, Direct Load Control (DLC) and Load shedding reserves to make up the load imbalance. Then, the formulated problem can be solved by the Probabilistic Dynamic Programming (PDP) method. In case study, we divide two cases for comparing the cost function between the conventional method and the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.264-265
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• 2006

This paper presents direct load control algorithm based locational and electric load characteristics. Direct load control is defined that demand-side management program activities that can interrupt consumer load at the time of annual peak load by direct control of the utility system operator by interruption power supply to individual appliances or equipment on consumer premises. Korean power system is divided into 14-areas considering branches operating in KEPCO, and electric loads are classified into 19 load groups considering interruption costs in this paper. The purpose of proposed method is to decrease social losses by controlling electric loads mainly whose interruption costs are low. It is expected that the proposed algorithm can be used as the countermeasure for the emergency state of the electric power dispatch in a operation point of view.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.783-787
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• 1996

The rapid growth of air conditioning load has become a main reason of peak load increase in summer. In connection with this, we surveyed the load management projects of utilities world wide and their detailed activities. This study is to develop a remote load control system using computer and radio communications. We finished the field-test of this system on August 1995 in Seoul area. During the field-test, the remote load control of air conditioners was proved to be well-timed. Two control modes, group control and all control, are available for the user to select. The transmission reliability of the load control signal was very good and the functions of system hardware as well as the software were excellent. So we confirmed the applicability of the load control system including the pager communication network. In this paper, detailed information on the system functions and experimental results are described.

• 대한임베디드공학회논문지
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• 제9권3호
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• pp.137-143
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• 2014

Demand Controller is a load control device that monitor the current power consumption and calculate the forecast power to not exceed the power set by consumer. Accurate demand forecasting is important because of controlling the load use the way that sound a warning and then blocking the load when if forecasted demand exceed the power set by consumer. When if consumer with fluctuating power consumption use the existing forecasting method, management of demand control has the disadvantage of not stable. In this paper, load forecasting of the unit of seconds using the Exponential Smoothing Methods, ARIMA model, Kalman Filter is proposed. Also simulation of load forecasting of the unit of the seconds methods and existing forecasting methods is performed and analyzed the accuracy. As a result of simulation, the accuracy of load forecasting methods in seconds is higher.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.633-635
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• 2003

Electricity industries throughout the world are undergoing unprecedented changes. As a result, these changes lead to the separation of traditional integrated utilities and the introduction of competition in order that increase efficiency in electricity industry. Direct load control (DLC) system in competitive electricity market has a hierarchical interactive operation system, therefore, its control logic is also applied by bilateral interactive method that interchanges information related to interruptible load between operation hierarchies. Consequently, load curtailment allocation algorithm appropriate for new DLC system is required, and based on interchanged information, this algorithm should be implemented by most efficient way for each operation hierarchy. In this paper, we develop the load curtailment allocation algorithm in an emergency for new DLC system. Especially, the optimal algorithm for load aggregator (LA) that participates in competitive electricity market as a main operator for load management is developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.196-198
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• 2003

The low load power factor causes various problems such as the increase of the power loss and the voltage instability. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power troublesome, from which the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is derived and its effects in supplying the reactive power and enhancing the load power factor are analyzed in a small-scale power system. The load power factor sensitivity of the generation cost is applied for determining the locations and capacities of reactive power compensation devices. It is shown that the generation cost can be reduced and the system power factor can be enhanced effectively using the load power factor sensitivity.