발전기 공급능력 산정 및 예측 기술개발

김의환,안영모,홍은기,Kim, Euihwan,An, Youngmo,Hong, Eunkee 한국전력공사 2016 KEPCO Journal on electric power and energy Vol.2 No.3

Supply Capability of the generator, if the maximum demand occurs, refers to the maximum power that can be stably supplied and it is possible to maintain stable power supply to be greater than actual load. However, unexpected power demand and reduction in supply Capability due to stop of unexpected generator in operation can temporarily make a big chaos in power system. In fact, due to a lack of power supply Capability in the country, enforced emergency load adjustment to the September 15, 2011, the circulation power outage has occurred in several cities. As the result, interrupted operation of the elevator and stopped hospital medical equipment led to a great deal of trouble to people's lives, causing a social problem. At that time, it was found that a failed frequency control because of smaller actual supply Capability than that of predicted. The difference was about 1,170 MW with Gas turbine power plant. By accurately calculating the generator supply capability, we can not only grasp the power reserve rate, but also correspond to the time of power supply instability.

Performance Analysis of long term operation for photovoltaic system

김의환(Kim, EuiHwan),김정삼(Kim, Jungsam) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05

This study analyzed the performance of long term operation photovoltaic system The 50 kWp grid connected photovoltaic system which was installed at KEPRI site in 1999 has been operated more than 12 years. In order to acquire long term operation characteristics of medium size photovoltaic system, the operation test data related on power generation electricity and capacity factor of 50 kWp system, which have been collected since 1999, were analysed. From the analysing results, 57.7 MWh in annual power generation electricity of 50 kWp photovoltaic system in 1999 has been decreased 49.1 MWh in 2005 and reached 38.0 MWh in 2010. In addition to, the capacity factor of 50 kWp photovoltaic system also showed 13.2 % in 1999, 11.2% in 2005 and finally reached 8.8% in 2011. The operation test data showed a trend of decreasing of generation electricity and capacity factor during the 12 years operation time and we guessed that was caused by solar cell performance degradation and decreasing of PCS system efficiency.

The study on construction of the practical testing ground of grid-connected photovoltaic system

김의환(Kim, Euihwan),장주연(Jang, Juyeon) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06

Currently the variety of governmental business support and research for supplying solar energy have been actively progressed. As of now, however, There are no practical testing infrastructures of grid-connected photovoltaic system which test performance of solar power facility in domestic. Therefore, in KEPRI, there is in progress construction of practical testing ground of 500 kW class grid-connected PV System for developing the evaluation of the performance technology including the Module, PCS, and etc, that is the important instrument of the PV System, in Gochang area. It analyzed the site creation work for constructing the practical testing ground and new construction of control room and the unit standards, specifications and capacity of required equipment. For the system detailed design, configuration, instrument-specific parameters established, power generation predictions of Array Type and the components of testing ground are needed to build.

사용자 행동과 웹 페이지 분석을 통한 자동 태깅 시스템

김의환(Euihwan Kim),이승훈(Seunghoon Lee),윤태복(Taebok Yoon),이지형(Jee-Hyong Lee) 한국지능시스템학회 2008 한국지능시스템학회 학술발표 논문집 Vol.18 No.2

웹 페이지의 생성 및 웹이 가진 정보량은 기하급수적으로 늘고 있다. 이로 인해 사용자의 검색 목적을 파악하여 효율을 높이기 위한 다양한 방법이 연구되고 있으며, 태그를 사용하는 방법이 하나의 대안으로 떠오르고 있다. 태그는 해당 페이지의 대표 키워드를 의미하므로 검색의 기준을 마련할 수 있으나 사용자의 주관적 관점에서 생성하기 때문에 같은 태그라 할지라도 그 의미가 다를 수 있다. 본 논문에서는 태그의 객관성을 부여하는 방법을 제안한다. 정보를 검색하기 위해 사용자들이 입력한 검색어와 웹 페이지에서의 사용자의 행동 패턴을 근거로 의미있는 정보가 담긴 웹 페이지를 선별하고, 페이지 분석과 검색어를 이용하여 태그를 생성한다. 이러한 알고리즘을 이용하여 특정 사용자의 부수적 행동에 의한 태깅이 아닌 다수 사용자의 행동에 의한 웹 페이지 자동 태깅 시스템을 구축하였다. 또한 기존 검색 방법과의 비교 분석을 통해 제안하는 알고리즘의 성능을 평가하고 타당함을 검증하였다.

유도무기 비행시험 업무 개선을 위한 낭비요인과 우선순위 분석 연구

안장근,김의환,Ahn, Jangkeun,Kim, Euihwan 한국군사과학기술학회 2018 한국군사과학기술학회지 Vol.21 No.4

The works of preparing for missile flight test are becoming more complicated. To reduce the amount of waste time along with the complexity of the task, systematic analysis of waste factors should be performed before performing process improvement. The waste factors for missile flight test are first defined using lean-based waste factors. The improvement priorities for the defined waste factors are surveyed. For reliable analysis, AHP is used in questionnaire analysis instead of the existing method with large error. Then weighting and priority for waste factors for level 1 and Level 2 are suggested. Through AHP, we could derive reliable improvement priorities for waste factors. It is analyzed that the biggest cause of waste factors is waiting time and identified as the first item to be considered when establishing improvement plan. In addition, suggestions for improvement measures of waste factors are presented through brainstorming method. Reliable results will be an important factor in process redesign for missile flight test works.

Study on the Elicitation of Parameter in Designing each Capacity of PV System for Power Industry

김병만(Kim, ByeongMan),이길송(Lee, KilSong),양연원(Yang, YeonWon),신현우(Shin, HyunWoo),김의환(Kim, EuiHwan) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06

Recently, as much supplied with new-renewable energy, as much invested in PV system. PV system consists of PV module, PCS and Monitering system, and also could be classified into the type and the capacity by installation method and cost etc. When various systems are installed in the field, it is needed to research for applying in the field and establish infrastructure in order to ensure stable efficiency and reliability. In this study, as the basic design of the demonstration test facility, it is designed the basic PV systems for each capacity to test each PCS. In addition, It is drew the climatic conditions such as insolation, temperature and the design parameters such as installation angle, shades for the local demonstration project and expected the generation of each PV system.

A Study on the Voltage Regulation Method Based on Artificial Neural Networks for Distribution Systems Interconnected with Distributed Generation

Rho Daeseok(노대석),Euihwan Kim(김의환) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.11

본 논문은 분산전원이 연계된 배전계통에 있어서 온 라인 리얼타임으로 조정이 가능한 최적 전압조정방안을 제시한다. 가능한 많은 수용가에게 적정한 전압을 공급하기 위하여 최적 송출전압이 결정되어져야 하는데, 여기서는 급변하는 배전계통의 급격한 부하변동과 분산전원의 불규칙적인 출력특성을 고려하기 위하여, 인공 신경회로망(ANN: Artificial Neural Network)을 이용한 최적 전압조정방안을 제시한다. 본 논문에서 제시한 알고리즘을 이용하여 배전 모델계통에 적용한 결과, 제안한 방법이 다수의 분산전원이 연계된 배전계통의 전압조정에 실용적인 방책임을 확인하였다. This paper deals with the optimal on-line real time voltage regulation methods in power distribution systems interconnected with the Distributed Generation(DG) systems. In order to deliver suitable voltage to as many customers as possible, the optimal sending voltage should be decided by the effective voltage regulation method by using artificial neural networks to consider the rapid load variation and random operation characteristics of DG systems. The results from a case study show that the proposed method can be a practical tool for the voltage regulation in distribution systems including many DG systems.

유도인형훈련시스템의 개발

박강(Kang Park),심철동(Cheol Dong Shim),김의환(Euihwan Kim),김성섭(Sungsup Kim),김태완(Taehwan Kim) (사)한국CDE학회 2010 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2010 No.1

Traditional Judo training requires a human training partner. Unfortunately it is not always easy to find one. Multifunctional Judo-doll training system has therefore been developed, and is described here. The system consists of a dummy, a power generating mechanism, and kinematic links. The power-generating mechanism generates forces similar to those of a human, by adjusting deadweights and controlling powderbrake"s forces. The powderbrake force is controlled by the microprocessor according to the exercise scenario. The kinetic links, which mimic a human training partner’s motions, has been developed based on a ViconTM system’s analysis of the movement of human training partners. This mechanism whose name is "L link-wire" consists of L type links, wire, roller, and dead weight. This mechanism generates the force that leads the link to the neutral position regardless the link is pushed or pulled. The lifting mechanism that lifts the doll when the one-armed shoulder throw skill is applied is also developed. A 32-bit microprocessor controls the whole system; it reads the loadcell data, controls the electromagnetic force, and communicates with a PC via Bluetooth. The training history, including loadcell data, date, and training time, is stored in the PC for analysis. This training system can be used to enhance the Judo performance of any self training player.

유도 경기력 향상을 위한 유도 인형시스템 개발

박강(Kang Park),심철동(Cheol Dong Shim),김의환(Euihwan Kim),김성섭(Sungsup Kim),김태완(Taewhan Kim) (사)한국CDE학회 2010 한국CDE학회 논문집 Vol.15 No.5

The purpose of this study is to develop three Judo-doll systems for enhancement of Judo’s performance. Traditional Judo training requires a human training partner. Unfortunately it is not always easy to find one. Multifunctional Judo-doll training system has therefore been developed, and is described here. The system consists of a dummy, a power generating mechanism, and kinematic links. The power-generating mechanism generates forces similar to those of a human, by adjusting deadweights and controlling powderbrake"s forces. The powderbrake force is controlled by the microprocessor according to the exercise scenario. The kinetic links, which mimic a human training partner’s motions, has been developed based on a Vicon<SUP>TM</SUP> system’s analysis of the movement of human training partners. This mechanism whose name is “L link-wire” consists of L type links, wire, roller, and dead weight. This mechanism generates the force that leads the link to the neutral position regardless the link is pushed or pulled. The lifting mechanism that lifts the doll when the one-armed shoulder throw skill is applied is also developed. A 32-bit microprocessor controls the whole system; it reads the loadcell data, controls the electromagnetic force, and communicates with a PC via Bluetooth. The training history, including loadcell data, date, and training time, is stored in the PC for analysis. This training system can be used to enhance the Judo performance of any self training player.