• 전력전자학회:학술대회논문집
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• 전력전자학회 2009년도 정기총회 및 추계학술대회 논문집
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• pp.105-110
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• 2009

The On Line Electric Vehicles(OLEV) that can pick up inductive power from underground coils on driving with high efficiency have been developed this year, and is now proposed in this paper. The IPS(Inductive Power Supply) system consists of power supply inverters, power supply rails, pick up modules, and a regulator. There are 3 generations of IPS have been developed so far, and the $4^{th}$ generation IPS is being developed. The $1^{st}$ generation has been demonstrated this Feb. 27, which is equipped with mechanically auto tracking pick-up module with 1cm air gap, and showed 80% power efficiency. The $2^{nd}$ generation IPS applied to an 120kW (average)/240kW(peak) motor powered electric bus has 17cm air gap with 72% power efficiency. For the $2^{nd}$ generation IPS, the Power supply inverter has 440V, 3phase input and 200A @ 20kHz output. The test power supply rail of 240m long is segmented by 60m each, where newly developed core structure and power cable are constructed under the road covered with asphalt of 5cm thickness. The pick-up modules which consist of core, winding wire, and rectifiers are fixed to the bottom of the bus which can carry more than 40 passengers and can pick up max. 60kW. To remove parasitic component and to transfer maximum power between them resonant circuit topology is applied to the primary and secondary sides. The EMF level is below 62.5mG at 1.75m from the center of the road to meet the regulation. Several effective ways of reducing EMF levels have been developed. In addition, effective ways to solve problems related high frequency power cables buried in ground and it's proof from soil have been studied also. This development shows that the IPS system is capable of supplying enough power to the pick-up of OLEV and can reduce battery size, weight and cost, which means the IPS with OLEV is one of the best candidate for EV.

• 항공우주시스템공학회지
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• 제17권1호
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• pp.88-96
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• 2023

우리나라에서 개발 중인 저궤도 위성은 아리랑 위성으로, 이제까지 꾸준한 성능향상이 있었다. 이때 탑재체의 성능향상에 따른 탑재체의 전력요구도는 늘어나게 되었고 이에 위성 내부 전력 공급장치의 설계 및 Solar Array의 구성 등 위성 설계가 달라진다. 이에 따라 위성에 전력을 공급하며 위성 통합시험을 진행하는 전력계 전기지상지원장비 설계 시 전력 증가에 따라 많은 고려사항이 필요로 한다. 본 논문은 탑재체에 따른 위성 전력요구도의 변화 및 전력요구도 증가에 따른 전력계 전기지상지원장비 설계 시 고려할 사항에 대해서 다룬다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 추계학술대회
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• pp.215-218
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• 2013

본 논문은 낙뢰 Surge 방호를 위하여 독립접지를 공통접지로 개선하는 효율적인 방법을 제안하였다. 낙뢰 Surge 방호를 위해서는 등전위 이론에 근거하는 공통접지방식이 적합하고, 중성선이 있는 전원계통에서는 공통접지방식을 사용하는 것이 국제적으로 통용되는 기술규격이다. 따라서 낙뢰 Surge에 취약한 문제점을 갖고 있는 기존의 중성선이 없는 전원계통의 독립접지방식을 중성선이 있는 전원계통의 공통접지방식으로 개선을 하고, 정전압소자를 이용하여 낙뢰 Surge를 방호하는 효율적인 등전위 시스템 구축 방법을 제안한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.878-884
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• 2006

Grounding fault and short of the DC power supply systems are detected and protected by high-speed circuit breaker, linked breaking device, ground relay and fault selective device, all of which are installed and operated in substaions. however, there have been many cases in which the protective devices did not detect grounding of of the over head catenary systems on concrete support for an extended period of time. Such cases often cause severe damages to the supports with high grounding resistances. If grounding accidents occur repetitively, the earth current and the rise of earth potential can damage not only passenger and staff but also electric facilities and equipment, necessitating high cost and endeavor to restore. The following study points out various problems that can be occurred occur as a result of high impedance grounding accident, and proposes a new system which can protect and intercept them.

• 수산해양기술연구
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• 제55권4호
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• pp.363-371
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• 2019

Thousands of demersal fishes inhabit in the waters around Korea and most of them are overexploited. One of reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the Danish seine fishery from 1960s to 2010s. Gross tonnage was decreased stably, but the horse power was increased annually. The length of ground rope, warp and hand rope was somewhat longer, but changed a little. Color fish finder was utilized from the mid-1960s and positioning system was used five years later. A hydraulic line hauler were introduced in the mid-1980s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting researchers. Therefore, the relative fishing power index in the Danish seine fishery increased stably from 1.0 in 1970 to 1.0 in 1980, to 1.2 in 1990, to 1.3 in 2000 and to 1.3 in 2010. The results are expected to contribute to reasonable fisheries stock management.

• 한국지열·수열에너지학회논문집
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• 제13권2호
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• pp.22-29
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• 2017

This study is performed to performance of the combined system the GSHP (Ground Source Heat Pump) system with the Earth tube system using EnergyPlus program. The Earth tube system using fan is characteristics as supply lower (higher) air temperature than outdoor air temperature in cooling and heating seasons, the GSHP system is characteristics as small indoor air temperature variation range. As the results of Earth tube + GSHP system simulation, GSHP power can be reduced than the GSHP single operation as 17.3% in cooling seasons and 32.5% in heating seasons, the GSHP design capacity can be replaced more small size.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1807-1813
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• 2018

In this paper, the fault line selection and location problems of single line-to-ground (SLG) fault in distribution network are addressed. Firstly, the adaptive filtering property for empirical mode decomposition is formulated. Then in view of the different characteristics showed by the intrinsic mode functions(IMF) under different fault inception angles obtained by empirical mode decomposition, the sign of peak value about the low-frequency IMF and the capacitance transient energy is chosen as the fault line selection criteria according to the different proportion occupied by the low-frequency components. Finally, the fault location is determined based upon the comparison result with adjacent fault passage indicators' (FPI) waveform on the strength of the interaction between the distribution terminal unit(DTU) and the FPI. Moreover, the logic nodes regarding to fault line selection and location are newly expanded according to IEC61850, which also provides reference to acquaint the DTU or FPI's function and monitoring. The simulation results validate the effectiveness of the proposed fault line selection and location methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1438-1440
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• 2005

A power control and distribution unit(PCDU) plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. In this work, we perform the preliminary design of a PCDU scheme for the small LEO Satellite applications. The main constitutes of the PCDU are the battery interface module, the auxiliary supply modules, solar array regulators with maximum power point tracking(MPPT) technology, heater power distribution modules, internal converter modules for regulated bus voltage generation. and instrument power distribution modules.

• 한국산학기술학회논문지
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• 제18권9호
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• pp.42-51
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• 2017

본 논문에서는 전기자동차 배터리의 충전 방안 중 하나로 여겨지는 무선전력전송을 이용할 경우 발생 가능한 보호협조 문제점을 분석한다. 전기충전을 위한 무선전력전송 시스템을 구축하기 위해서는 전원공급장치 개발이 필수적이나, 전원공급장치의 정확한 설치기준이 없기 때문에 운용 시 보호협조 상에 문제점이 발생 할 수 있다. 따라서 본 논문에서는 PSCAD/EMTDC로 무선전력전송 전기충전설비용 전원공급장치를 모델링하여 가능성 있는 사고를 모의해보고, 이를 해결할 수 있는 대안을 제시하고자 한다. 즉, 사고 발생 시, 전원공급장치의 60Hz 대역에서 정격차단용량(12.5kA) 상회 가능성과 20kHz 대역에서의 임피던스 병렬화로 인한 보호기기의 부동작 가능성을 시뮬레이션을 통해 확인하였고, 이에 대한 해결책으로 대칭좌표법을 이용한 사고해석 알고리즘과 사고전류를 저감시킬 수 있는 NGR 산정 알고리즘을 제안하였다. 이를 통해 60Hz 대역에서는 NGR(Neutral Ground Resister)을 도입하여 사고전류를 정격차단용량 이하로 저감시키고, 20kHz 대역에서는 중선선에 CT 설치 및 이에 대한 보호정정을 통해 보호기기 부동작이 방지됨을 확인하였다.

• 한국철도학회논문집
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• 제12권5호
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• pp.687-693
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• 2009

급전시뮬레이션과 함께 수행될 수 있는 '레일 전위 상승 분석을 위한 컴퓨터 알고리즘'이 제안되었다. 본 알고리즘에서 레일전위상승 분석은 2 단계로 진행된다. 첫 단계에서는 급전시스템의 조류해석을 수행하여 차량 및 변전소에서의 인젝션(injection) 전류를 구한다. 두 번째 단계에서는 급전시스템의 등가회로에서 변전소 및 차량을 전류 소스로 대치하고 레일의 대지로의 누설 저항이 삽입된 등가회로를 다시 구성한다. 새로 구성된 등가회로를 해석하여 변전소 및 차량 위치에서의 레일 전위를 구한다. 알고리즘의 타당성을 분석하기 위하여 컴퓨터 프로그램을 작성하여 레일전위상승을 구하였고 동일한 시스템을 대상으로 MatLab 사의 Simulink/SymPowerSystems 소프트웨어를 이용하여 레일전위를 구하였다. 2가지 방법에 의한 결과를 상호 비교 분석한 결과는 그 오차가 허용범위 내에 있음을 보여주었다. 본 알고리즘은 급전시뮬레이션과 연동하여 수행될 수 있는 장점을 가지고 있다.