• Nuclear Engineering and Technology
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• 제51권4호
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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.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.633-636
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• 2017

본 논문에서는 차량용 전장품의 복사내성 시험에 적합한 균일장 측정방법에 대해 연구하였다. 복사내성 평가는 전자파 방해원에 대해 시험품이 충분한 내성을 가지고 정상적인 동작을 하는지 확인하는 평가이다. 복사내성 평가 중 시험품과 하네스의 균일한 전계형성을 위해 균일장 검증은 필수적이나 차량용 전장품의 복사내성 평가규격인 ISO 11452-2에는 균일장 측정에 대한 명시가 없다. 이에 균일장 측정 방법이 명시된 타 국제 규격과의 비교/분석을 하였고, 그 결과 시험 방법과 차량 전장품에 적용되는 평가 환경의 상이함으로 인해 편차가 발생함을 확인 하였다. 본 논문에서는 차량 전장품의 복사내성 평가 환경이 고려된 균일장 측정방법을 제안하고 실제 측정을 통한 검증을 통해 타당성을 확인하고자 한다.

• 한국통신학회논문지
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• 제16권8호
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• pp.785-792
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• 1991

EMC 안테나의 트성평가용으로 사용할 안테나 시험장의 적합성을 평가하기 위한 반파장 공진 다이폴안테나를 설계하고, 안테나의 치수변화가 안테나 인자에 미치는 영향에 대하여 고찰하였다. 그 결과, 안테나의 길이 및 반경이 $\pm$1/mm/정도 변화하더라도 안테나 인자에는 큰 영향을 미치지 않는다는 것을 확인할 수 있었다. 또한, 설계이론의 타당성을 확인하기 위하여 실험결과와도 비교하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1619-1622
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• 2001

Recently many researches on the diagnosis of stator winding insulation for large rotating machines have been developed sine the 1970s. Capacitive coupler has been the most widely used sensor for on-line partial discharge(PD) in rotating machines. The 105 [pF] ceramic coupler(CC) has been developed to continuously measure the PD activity in operating motor stator windings. This paper presents frequency characteristics and laboratory test to compare traditional 80 [pF] epoxy-mica coupler(EMC) and 105 [pF] CC for PD measurement in 6.6 [kV] stator windings.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.777-789
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• 2001

The purpose of this study was to investigate the possibility of using surface electromyographic signals as a measure of muscle fatigue during the wheelchair propulsion. Subjects performed wheelchair exercise tests on a motor-driven treadmill with a constant-velocity of 1.25 m/sec. During each test, the raw EMC signals were acquired from the surface electrodes attached on the belly of five muscle groups: biceps brachii, pectoralis major. deltoid, triceps brachii, and trapezius. The median power frequency(MPF), and the root mean square(RMS) amplitude were calculated for each cyclic contraction in order to quantify muscle fatigue. During the wheelchair propulsion, the MPF decreased and the RMS increased in the trapezius and deltoid. However, the decreasing MPF and the increasing RMS also fluctuated severly during dynamic muscle contractions. Therefore, the MPF and RMS values should be estimated with well-designed methods and used with caution to quantify muscle fatigue during wheelchair propulsion.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.47-53
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• 2003

Screen filter of PDP TV plays an important role in satisfying the EMI/EMC specifications. Two types of filters, the mesh type and the sputter type, are used in PDP TVs, and this paper presents measurement results of the shielding effectiveness (SE) in the frequency range from 50MHz to 1GHz. Two methods were used for the measurement, one using network analyzer (NA) in an open area test site(OATS), and the other using the screen room. The overall conclusion is that the shielding effectiveness of the screen filter is related to the surface resistance of the screen filter. The mesh type screen filters are superior to the sputter types in the shielding effectiveness, which is varying with the frequency.

• Journal of electromagnetic engineering and science
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• 제4권2호
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• pp.51-55
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• 2004

With the progress of the electronics industry and radio communication technology, certain problems, such as electromagnetic interference(EMI), have arisen due to the increased use of electromagnetic(EM) waves. International organizations such as CISPR, FCC, and ANSI have provided the standards for the EM wave environment and for the countermeasure of the electromagnetic compatibility(EMC). EM wave absorbers are used for constructing an anechoic chamber to test and measure EMI and electromagnetic susceptibility(EMS). In this paper, we have designed an one-body EM(electromagnetic) wave ferrite absorber, based on the equivalent material constants method for both normally and obliquely incident waves, whose absorption abilities are superior to that of the conventional ones. The fabricated absorber has a thickness of 27.68 mm and shows an absorption ability over 20 ㏈ in the frequency from 30 MHz to 6 ㎓.

• Journal of Welding and Joining
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• 제18권2호
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• pp.222-222
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• 2000

PBGA(Plastic Ball Grid Array) is composed of some materials such as PCB(Printed Circuit Board), epoxy molding compound, die attach and so on. Reliability of PBGA package is weak compared with plastic packages. The weak points of reliability are the lower resistance to popcorn cracking, which is induced by moisture absorption in PCB, and the pressure cooker test corrosion, which is the basic problem due to the material characteristics of PCB. Introducing the PCB baking and the plasma treatment cleared the popcorn cracking phenomenon. The PCB baking and plasma treatment reduced the epoxy void by eliminating the source of moisture vaporization during the epoxy curing and enhanced the adhesion between PCB and epoxy. Also, plasma treatment enhanced the wettability of epoxy on PCB. The problem of corrosion is cleared using multi-functional epoxy. This type of EMC(Epoxy Molding Compound) is recommended in package using PCB as a substrate. (Received November 19, 1999)

• Journal of Welding and Joining
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• 제18권2호
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• pp.95-99
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• 2000

PBGA(Plastic Ball Grid Array) is composed of some materials such as PCB(Printed Circuit Board), epoxy molding compound, die attach and so on. Reliability of PBGA package is weak compared with plastic packages. The weak points of reliability are the lower resistance to popcorn cracking, which is induced by moisture absorption in PCB, and the pressure cooker test corrosion, which is the basic problem due to the material characteristics of PCB. Introducing the PCB banking and the plasma treatment cleared the popcorn cracking phenomenon. The PCB banking and plasma treatment reduced the epoxy void by eliminating the source of moisture vaporization during the epoxy curing and enhanced the adhesion between PCB and epoxy. Also, plasma treatment enhanced the wettability of epoxy on PCB. The problem of corrosion is cleared using multi-functional epoxy. This type of EMC(Epoxy Molding Compound) is recommended in package using PCB as a substrate.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2003년도 한국우주과학회보 제12권2호
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• pp.106-106
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• 2003

인공위성의 전기적 호환성 해석은 인공위성의 각 유닛들에서 발생할 수 있는 잡음이 인공위성의 정상 동작에 미치는 영향을 분석하고 그 영향을 최소로 만들 수 있는 방안을 연구하기 위해 필요하다. 본 논문에서는 인공위성의 탑제컴퓨터와 탑제체 간의 인터페이스에서 전기 신호의 호환성 해석, Harness의 호환성 해석 그리고 radiation 해석이 이루어졌다. 인공위성의 탑제컴퓨터와 탑제체 간의 인터페이스에서 전기 신호의 호환성 해석은 전기 신호의 전압 레벨이 전압 히스테리시스의 경계 영역에서 충분한 여유를 가지고 있는지 판단하기 위해 필요하다. 전기 신호에 충분한 여유분이 없는 경우 여유분을 증가시키기 위한 방법이 제안되었으며 제안된 방법에 의해 인터페이스의 올바른 동작에 충분한 여유분이 생겼음이 시뮬레이션 결과에 나타났다. Harness의 호환성 해석은 다목적실용위성 2호에 사용된 Harness에 대한 conductive epoxy potting의 전도도를 검증하기 위해 이루어졌다. 본 논문에서는 전송 임피던스 측정 방법을 이용하여 epoxy potting의 전도성이 모든 주파수 영역에서 인공위성의 요구사항에 만족함을 보여준다. Radiation 해석은 인공위성 시스템의 radiated emission(RE)을 추정하고 S-band 수신기와 GPS 안테나와 같은 수신단에 대한 상호간섭에 의한 위험도를 분석하기 위해 필요하다. RF 수신기의 수신 대역에서 발생한 잡음의 영향으로 신호대잡음비가 허용수치이하로 감소하여 위성 명령을 수신하는 동작에 지장을 초래할 수 있다. 본 논문에서는 RF 수신단에 가장 큰 영향을 미칠 것으로 예상되는 star tracker의 RE test 결과를 분석하여 test 결과가 GPS 수신기와 S-band 수신기의 각각의 성능에 적합한지 해석하였다. 또한 solar array regulator의 스윗칭에 의해 발생되는 radiation이 위성 구조체에 미치는 영향을 해석하고 시뮬레이션 하였다.