인공 화염으로 인한 가공 송전선의 기계적, 재료적 특성에 관한 연구

이대동(Dae-Dong Lee),현동석(Dong-Seok Hyun),심재명(Jae-Myung Shim),김영달(Young-Dal Kim) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7

Generally, the deterioration characteristics of a conductor affected by a forest fire can be analyzed through simulation of a forest fire and results of the simulation. However, there are little accomplishments of that kind of simulation applied to the power transmission, and there aren't actual analysis for a sample exposed in a forest fire. This paper deals with the experimental results that apply to a new wire by an artificial flame equipment because it's difficult to directly analyze the characteristic by a forest fire. Also, after an artificial flame is applied to a normal ACSR for various experimental conditions, changes of mechanical and material characteristics of the ACSR were analyzed by the surface inspection and load-tests of tensile of the ACSR. Then, the database will be made to made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

국내 배전계통의 6분할 3연계 최적분할 모델 구성방안

이대동(Dae-Dong Lee),손성환(Sung-Hwan Son),하복남(Bok-Nam Ha),현동석(Dong-Seok Hyun),김영달(Young-Dal Kim) 대한전기학회 2010 전기학회논문지 P Vol.59 No.4

According as economy grows, demand for power increases and satisfaction of customer about electricity quality is rising. There is in trend that investment expense by continuously increased supply of electric power equipment is on the increase continuously, but management efficiency improvement through curtailment of supply of electric power equipment investment expense through efficient operation is required rather than to increase investment. In this study, reconsidered about 6 divisions 3 ties that is distribution line basis configuration of Daejeon · Geumsan area and analyzed division and tie present condition of truthful distribution System. Examined problem analyzing average division number, tie number and tie switch number, searched about most suitable division that consider load. Hereafter, I wish to take advantage of analysis result in most suitable division and tie of truthful distribution system for power failure section reduction and investment expense curtailment.

열전달해석을 이용한 고속철도용 제동저항기의 온도특성 분석

이대동(Dae-Dong Lee) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.- No.-

고속철도의 중요 부품인 모터블럭 제동저항기는 평상시 회생제동을 사용하나 모터블럭에 입력되는 전류가 제한치 이상일 때에는 발전제동으로 전환하여 발생되어진 전기에너지를 제동저항기를 통해 열로서 소비시키는 장치이다. 고속철도 차량의 발전제동 시 제동저항기에 높은 열이 발생하면 제동저항기 선재의 소손이 일어나 제동초퍼를 손상시키고 견인용 인버터 및 전동기에도 영향을 미쳐 가감속 제어운전을 어렵게 만든다. 따라서 본 논문에서는 설계한 제동저항기를 현차와 유사한 조건의 고속철도 추진제어장치에 탑재하고 제동전류 변화에 따른 열전달 해석 및 온도특성실험을 수행하여 결과를 분석하였다.

고온의 화염에 열화된 ACSR의 표면 및 인장강도 분석

이대동(Dae-Dong Lee),심재명(Jae-Myung Shim) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.- No.-

송전선로에 주로 사용되어지는 ACSR은 외층이 알루미늄 연선이고 내층은 아연도금 강선으로 구성되어 있으며 알루미늄 연선은 전력을 공급하는 역할을 담당하고 아연도금 강선은 기계적인 인장을 담당하고 있다. 만약 산불이 발생할 경우에 화염에 노출된 ACSR은 재료의 구조가 변하여 기계적 인장이 감소될 뿐만 아니라 전기적 성질을 변화시켜 전선의 교체수명이 감소될 것이다. 따라서 본 논문에서는 고온의 인공화염에 열화된 ACSR 410mm2 아연도금 강선 및 알루미늄 연선을 대상으로 표면을 촬영하고 인장강도를 분석하였다.

해상 풍력발전단지 조성에 따른 레이더 전파간섭 저감 기술동향

김영달,정윤미,이대동,Kim, Young-Dal,Jeong, Yun-Mi,Lee, Dae-Dong 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.4

The wind power generation is an eco-friendly clean energy that produces almost zero $CO_2$ emission, and has a good economic feasibility. As for the location, the installation of large turbines and construction of large-scale wind farm is easier on the offshore than on the land. In Korea, it is inevitable to generate offshore wind power through the offshore wind farm, and the radio interference of larger wind power generators and offshore wind power farm to broadcasting, communication and radars is becoming a core issue for constructing the offshore wind farm. In this study, the wind power generation status and rotor blade technology trend were presented, along with the technical trend of radar radio interference reduction relating to construction of the offshore wind farm.

고온초전도 동기모터의 계자손실 해석 및 냉각 해석

김기찬(Ki-Chan Kim),이대동(Dae-Dong Lee) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.3

산업현장에서 사용되는 대형 모터는 전기자권선의 절연내력 저하 및 과열문제 등으로 인하여 정지사고의 위험이 높고 산업재해의 규모가 크므로 넓은 장소의 확보가 필요하다. 따라서 기존 모터에 비해 소형, 경량이면서 절연내력이 뛰어난 대용량 모터가 요구되어지고 있으며 이에 대한 연구가 활발히 진행되어지고 있다. 초전도 모터는 기존의 발전기나 모터와 같은 회전기의 계자코일을 초전도 화하여 계자의 발생을 크게 증가시킴으로서, 기기의 효율과 출력을 높이고, 소형화 및 경량화, 안정도 향상 등의 장점을 가지고 있으므로 초전도 선재의 성능을 발휘할 수 있도록 선제의 임계온도 이하로 낮추어줄 수 있는 냉각시스템의 설계 및 해석기술이 매우 중요하다. 따라서 본 연구에서는 100HP 고온초전도 동기모터의 개념설계를 통한 계자손실 해석과 냉각시스템의 저온 열전달 해석을 수행하였다. 계자손실 해석 결과, 고온초전도 선재를 사용하게 되면 균일한 공극자속밀도가 나타남을 확인하였다. 그리고 가스네온 및 액체네온에 대한 저온 열전달 해석 결과, 고온초전도 선재의 저온 안정성을 유지하기 위해서는 액체네온 1kg/min의 유량의 사용이 적합함을 확인하였다. Large industrial motors require a large area because of the high risk of shutdown accidents and large industrial accidents due to the lowering of the dielectric strength of the armature windings and overheating problems. Therefore, there is a demand for a large-capacity motor that has small size, light weight, and excellent dielectric strength compared with conventional motors. Superconducting motors have advantages of high efficiency and output power, low size, low weight, and improved stability. This results from greatly increasing the magnetic field generation by using superconductive field coils in rotating machines such as generators and motors. It is very important to design and analyze the cooling system to lower the critical temperature of the wires to achieve superconducting performance. In this study, a field loss analysis and low-temperature heat transfer analysis of the cooling system were performed through the conceptual design of a 100-HP high-temperature superconducting synchronous motor. The field loss analysis shows that a uniform pore magnetic flux density appears when high-temperature superconducting wire is used. The low-temperature heat transfer analysis for gaseous neon and liquid neon showed that a flow rate of 1 kg/min of liquid neon is suitable for maintaining low-temperature stability of the high-temperature superconducting wire.

열 열화에 따른 변압기 절연물의 절연특성 분석

이민구(Min-Gu Lee),심재명(Jae-Myung Shim),임경범(Kyung-Bum Lim),이대동(Dae-Dong Lee) 대한전기학회 2016 전기학회논문지 Vol.65 No.10

In this study shall investigate the influence upon the electrical property of transformer oil due to the heat among accelerated heat degradation experiment for a constant hour in the typical insulation oils of mineral base oil, silicon base oil and vegetable oil. In addition, the electric insulation performance of insulation materials in transformer shall be evaluated through the electric property analysis according to the heat degradation of epoxy insulation material, which has been used for electric facilities such as a molded transformer.

전력용 콘덴서 설치위치에 따른 분기선로의 전력손실 최소화 방안

이재환(Jae-Hwan Lee),김영달(Young-Dal Kim),이대동(Dae-Dong Lee) 대한전기학회 2019 전기학회논문지 Vol.68 No.6

To reduce energy consumption, consumers are reducing electricity costs by reducing power loss by power factor improvement by installing a power capacitor. However, since the installation location of the power capacitor is not specified in detail, it is difficult to loss reduction effect of the branch line because the customer is installed in the motor control center due to the maintenance and management convenience. Therefore, the power capacitor should be installed at the end (load terminal) of the line, which can greatly improve the power factor. In this paper, we propose a method to minimize the power loss of the branch line according to the optimum location of the power capacitor after calculating the loss reduction of the branch line through the installation and operation of the power capacitor.

직접전력변환 방식을 이용한 전압 sag/swell 보상기의 구현

차한주(Han-ju Cha),이대동(Dae-dong Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7

In this paper, a new single phase voltage sag/swell compensator using direct power conversion is introduced. A new compensator consists of input/output filter, series transformer and direct ac-ac converter, which is a single-phase back-to-back PWM converter without de-link capacitors. Advantages of the proposed compensator include: simple power circuit by eliminating de-link electrolytic capacitors and thereby, improved reliability and increased life time of the entire compensator; simple PWM strategy to compensate voltage sag/swell at the same time and reduced switching losses in the ac-ac converter. Further, the proposed scheme is able to adopt simple switch commutation method without requiring complex four-step commutation method commonly required in the direct power conversion. Simulation results are shown to demonstrate the advantages of the new compensator and PWM strategy.

직접전력변환 방식을 이용한 새로운 전압 sag/swell 보상기

차한주(Han-ju Cha),이대동(Dae-dong Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.4

In this paper, a new single phase voltage sag/swell compensator using direct power conversion is introduced. A new compensator consists of input/output filter, series transformer and direct ac-ac converter, which is a single-phase back-to-back PWM converter without dc-link capacitors. Advantages of the proposed compensator include: simple power circuit by eliminating de-link electrolytic capacitors and thereby, improved reliability and increased life time of the entire compensator; simple PWM strategy to compensate voltage sag/swell at the same time and reduced switching losses in the ac-ac converter. Further, the proposed scheme is able to adopt simple switch commutation method without requiring complex four-step commutation method commonly required in the direct power conversion. Simulation results are shown to demonstrate the advantages of the new compensator and PWM strategy.