• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.711-717
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• 2016

Recently, fuel cell generation system with high energy efficiency and low CO2 emission is energetically interconnected with distribution power system. Especially, MCFC(molten carbonate fuel cell) operating at high temperature conditions is commercialized and installed as a form of large scale power generation system. However, it is reported that power system disturbances such as harmonic distortion, surge phenomenon, unbalance current, EMI(Electromagnetic Interference), EMC (Electromagnetic Compatibility) and so on, have caused several problems including malfunction of protection device and damage of control devices in the large scale FCGS(Fuel Cell Generation System). Under these circumstances, this paper proposes countermeasure algorithms to prevent power system disturbances based on the modelling of PSCAD/EMTDC and P-SIM software. From the simulation results, it is confirmed that proposed algorithms are useful method for the stable operation of a large scale FCGS.

• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.63-77
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• 2008

With the limited frequency spectrum and an increasing demand for cellular communication services, the problem of channel assignment becomes increasingly important. However, finding a conflict free channel assignment with the minimum channel span is NP hard. The innovations are cellular concept, dynamic channel assignment and hierarchical network design. We consider the frequency assignment problem and the base station placement simultaneously. Our model takes the candidate locations emanating from this process and the cost of assigning a frequency, operating and maintaining equipment as an input. Hierarchical network design using genetic algorithm is the first three-tier (Macro, Micro, Pico) model. We increase the reality through applying to Electromagnetic Compatibility Constraints. Computational experiments on 72 problem instances which have $15{\sim}40$ candidate locations demonstrate the computational viability of our procedure. The result of experiments increases the reality and covers 90% of the demand.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.4
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• pp.83-93
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• 1994

1886년 고트리브 다이믈러와 칼 벤즈가 가솔린 자동차를 개발한 이후 100여년이 지난 지금 자동차는 비약적으로 진보, 발전하여 현대 산업사회와 개인의 생활에 있어 산업운송수단과 이동수단으 로서 필요불가결하게 되어 밀접한 관계를 갖고 있다. 우리나라 자동차 공업의 역사는 자동차가 사회적, 경제적 효용에 따라 그 생산과 보유대수가 날이 갈수록 증가 일로에 있으며, 자동차의 생산대수는 전세 계에서 년간 약 50,606천대('94년)로서 중요한 국가 기간 산업으로 자리하고 있다. 한편 전기, 전자공업의 발전에 따른 자동차의 Car Electronics가 많이 채용되게 됨에 따라 현재의 자 동차에는 대부분이 전자제어 System으로 구성되어 있다. 최근에는 Micro Processor를 이용한 전자부품이 많이 사용되어 전자파에 대한 문제가 다양하게 발생 하고 있다. 예를 들면 미국 캘리포니아주에서 전자점화제어장치와 연료분사 장치를 설치한 구미의 자동 차가 주행중 28MHz, 28W의 아마추어 무선을 탑제한 자동차가 통과할 때 엔진이 고르지 못한 보고가 있 었고, 화학섬유로된 옷을 착용한 전자부품이 다른 부품에 영향을 주는 사례가 맣아지고 있다. 따라서 자동차에는 여러가지의 전장품, 전자기기를 탑재하기 때문에 자동차 자체에서 발생하는 것과 외부로 부터 받는 전자장해 EMI(Electromagnetic Interference), EMS(Electromagnetic Susceptibility) 가 문제로 되어 자동차 및 부품 maker에 의한 EMC(Electromagnetic Compatibility) 평가의 중요성이 고조되고 있다. 차제무전기, 차제무전기, Car-Radio는잡음방해를 많이 받기도 하지만, 잡음원이 되기 도 한다. 또한 Engine 제어, 차속제어, Brake 제어등에 이용되는 전자제품은 방해에 의한 오동작 또는 파괴가 발생하여 주행기능, 안전성에 문제가 야기되지 않도록 해야 한다. 이러한 전자기 환경은 모두 RF(Radio Frequence)와 자동차에서의 전자파 장해 문제의 원이 될 수 있다. 자동차 및 그 부품의 전자기 방해에 관한 규격화는 1987년부터 괄목할 만하게 진행되어 이에 따른 규제 움직임이 IEC(International Electrotechnical Commission: 국제전기기술위원회) 산하의 하부기 구인 CISPR(International Special Committeeon Radio Interference: 국제 무선 장해 특별위원회)가 전자기 방해파에 대한 측정법 통일안을 제안 하였고, ISO(International Standardization Organiza- tion: 국제표준화 기구) 가운데 TC 22/SC3가 자동차의 전장품에 대한 장해를 논의히고 있다. 특히, 자동차의 EMC에 관한 국가 규격은 국제 규격에서 저술한 바와 같이 특별히 규정된 것이 없고 VDE(Verband Deutscher Elektrotechniker: 서독전기기술 협회)와 SAE(Society of Automotive Engi- neers: 자동차 기술자 협회)에서 비교적 활발하고 Jaso(Japanese Automobile Standards Organization: 일본 자동차 표준협회)에서 많이 진행중에 있다. 본 고에서는 자동차의 전자제어에 따른 잡음 발생 요인과 전자파 간섭 관련 자동차 규격과 시험평가 방법에 대해 간단히 소개 하였다.

• Journal of IKEEE
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• v.22 no.3
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• pp.854-857
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• 2018

It becomes important to analyze the effects of electromagnetic wave on human body, as various wireless equipments are widely used in daily life. SAR (specific absorption rate) is a parameter of the effects of electromagnetic wave on human body. However, it considers only human tissues, and it is difficult to evaluate the effects of electromagnetic wave when metal artifacts are inserted such as dental implants. This paper introduces a method to simulate SAR, and gets its simulated results. Simulated SAR of human head model with dental implants in 30 GHz 5th generation mobile communications (5G) frequency band is $2.50{\times}10^{-3}W/kg$ in maximum and $8.58{\times}10^{-7}W/kg$ in average. These values are absolutely below 1.6 W/kg Korean domestic SAR limit.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.636-645
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• 2015

In this paper, unusual harmonics noise problem of digital electronic products in mass production was introduced and a practical solution was proposed. Generally, 5th or higher harmonics noise level has been ignored in circuit designs because over 5th harmonics noise decreases by 40 (dB/decade). Through some measurements, it is confirmed that over 10th harmonics noise can propagate and radiate in case of a certain PCB or housing conditions. We propose a capacitively loaded micro-strip low pass filter for commercial products having spatial design constraints and measured the effectiveness. The proposed structure can solve both of the continual increment of harmonics noise level and the spatial design constraint of commercial products. We expect the proposed method be effectively used for various digital electronic products.

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.1-8
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• 2020

In this research, we develop an airborne equipment radiating S/C-band signal to a target located at a long distance. RF interface of the equipment comprises band-specific transmitters and an broadband antenna to satisfy EIRP(effective isotropic radiated power) requirements. The equipment is in a shape of a POD like an aircraft fuel tank. The measured weight of the equipment is 119.8 kg, the CG(center of gravity) is 1391.35 mm and the MOI(moment of inertia) are 46.07 ± 0.05(I_yy) kg·㎡, 45.36 ± 0.09(I_zz) kg·㎡. All results are found to meet the requirements for aircraft installation. To verify flight safety, EMI(electromagnetic interference) tests (RE102, CE102), environmental tests (high/low temperature operation, altitude), intra-system EMC(electromagnetic compatibility) and HERP(hazards electromagnetic radiation personnel) tests have been conducted and all the test results met the requirements. It is confirmed that the equipment could be mounted on the aircraft by meeting all electrical and mechanical requirements.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1032-1036
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• 2019

When the equipment which is related to safety or important to power production is installed in nuclear power plant units (NPPs), verification of equipment Electromagnetic Susceptibility (EMS) must be performed. The low-frequency radiated magnetic field susceptibility (RS101) test is one of the EMS tests specified in U.S NRC (Nuclear Regulatory Commission) Regulatory Guide (RG) 1.180 revision 1. The RS101 test verifies the ability of equipment installed in close proximity to sources of large radiated magnetic fields to withstand them. However, RG 1.180 revision 1 allows for an exemption of the low-frequency radiated magnetic susceptibility (RS101) test if the safety-related equipment will not be installed in areas with strong sources of magnetic fields. There is no specific exemption criterion in RG 1.180 revision 1. EPRI TR-102323 revision 4 specifically provides a guide that the low-frequency radiated magnetic field susceptibility (RS101) test can be conservatively exempted for equipment installed at least 1 m away from the sources of large magnetic fields (>300 A/m). But there is no exemption criterion for equipment installed within 1 m of the sources of smaller magnetic fields (<300 A/m). Since some types of equipment radiating magnetic flux are often installed near safety related equipment in an electrical equipment room (EER) and main control room (MCR), the RS101 test exemption criterion needs to be reasonably defined for the cases of installation within 1 m. There is also insufficient data regarding the strength of magnetic fields that can be used in NPPs. In order to ensure confidence in the RS101 test exemption criterion, we measured the strength of low-frequency radiated magnetic fields by distance. This study is expected to provide an insight into the RS101 test exemption criterion that meets the RG 1.180 revision 1. It also provides a margin analysis that can be used to mitigate the influence of low-frequency radiated magnetic field sources in NPPs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1040-1046
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• 2015

With the rapid progress of electronics and radio communication technology, human enjoys greater freedom in information communication. However, EMW (Electro-Magnetic Wave) environments have become more complicate and difficult to control. Thus, international organizations, such as the American National Standard Institution (ANSI), Federal Communications Commission (FCC), the Comite Internationale Special des Perturbations Radio Electrique (CISPR), etc, have provided standard for controlling the EM wave environments and for the countermeasure of the electromagnetic compatibility (EMC). In this paper, the status of EMW absorbers and the goal of smart EMW absorber in the future were described. Furthermore, design method of the smart EM wave absorber with heat radiating function was suggested. The designed smart EM wave absorber has the absorption ability of more than 20 dB from 2 GHz to 2.45 GHz band, the optimum aperture (hole) size, the adjacent hole space, and the thickness of which were 6 mm, 9 mm, and 6.5 mm, respectively. Thus, it is respected that these results can be applied as various EMC devices in electronic, communication, and controlling systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.77-86
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• 2005

The DC protection and control device for the feeding system of a Light Rail Transit(LRT) system is developed. For the development, the short circuit characteristics in the system are analyzed. As a result a protection algorithm for the DC fault selective relay (50F) is newly proposed, and principles of the DC fault selective relay, Line Test Device (LTD), DC Over Current Relay (DC OCR) are introduced From the development, the specifications and codes used to be unclear have become clarified and summarized. Moreover, the methods to examine the protective characteristics and Electromagnetic Compatibility (EMC) are established Finally, the performance and the effectiveness of the developed protective relay have been verified with the test based on IEC. For the reliability of the system, the relay has been installed and is being operated at the test track of the LRT system at Gyeong-San.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.10
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• pp.841-850
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• 2015

With the rapid progress of electronics and radio communication technology, human enjoys greater freedom in information communication. However, EMW(Electro-Magnetic Wave) environments have become more complicate and difficult to control. Thus, international organizations, such as the American National Standard Institution(ANSI), Federal Communications Commission(FCC), the Comite Internationale Special des Perturbations Radio Electrique(CISPR), etc, have provided standard for controlling the EM wave environments and for the countermeasure of the electromagnetic compatibility(EMC). In this paper, fabrication of the smart EMW absorber which has heat radiating function and high performance absorption abilities were suggested. Furthermore, we prospected future smart EMW absorbers. The designed smart EMW absorber is fabricated following process. Firstly, we applied high temperature heat treated to a mixture of Iron-oxide($Fe_2O_3$) and ceramics. Secondly, we applied low temperature heat treated to the mixture of heat treated material and a carbon material. Lastly, we made apertures on the absorber. The designed smart EM wave absorber has the absorption ability of more than 20 dB from 2 GHz to 2.45 GHz band, respectively. Thus, it is respected that these results can be applied as various EMC devices in electronic, communication, and controlling systems.