• 조명전기설비학회논문지
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• 제16권1호
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• pp.27-34
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• 2002

본 연구에서는 불평등 전계인 침대침 갭을 수평배치하였을 때, 고전압 전극 부근에 설치한 화염에 의한 교류 및 직류 섬락전압 특성을 조사하였다. 화염에 의해 섬락이 발생할 때, 코로나 개시전압과 섬락극성을 조사하기 위해 전압 및 전류파형을 측정하였으며, 인가전압의 상승에 따른 코로나풍과 쿨롱력에 의한 화염의 형상이 왜곡되고 요동되는 현상을 관찰하였다. 실험 결과, 화염이 전극의 중간위치에 있을 때 화염에 의한 교류 섬락전압은 화염이 없는 경우에 비해 평균 62.7[%] 저하된 것으로 나타났으며, 화염의 높이에 따른 섬락전압의 특성에서 화염의 높이 h=5, h=7 및 h=9[cm]인 경우 교류 섬락전압의 평균값은 화염이 없을 때에 비해 각각 34.2[%], 27.3[%] 및 21.4[%] 저하된 것으로 나타났다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권12호
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• pp.627-632
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• 2001

There are claims that ESE(Early streamer emission) Air terminals offer a vastly increased zone of protection over that of traditional lightning rods by causing the emission of an upward streamer/leader that will propagate towards the tip of downward leader at an early stage in the attachment process than would occur for a simple rod in the same geometrical configurations. This paper shows the results of comparing test a particular type of ESE air terminals with a simple rod conducted in the KEH HV laboratory, which are lightning impulse voltage test, flashover direction test and corona emission current measurement. The results from this test show a completely random scattering of flashovers to the conventional and ESE air terminals under identical electrics] and geometrical conditions, and thus shows no advantage of one terminal over the other.

• 인터넷정보학회논문지
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• 제22권2호
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• pp.109-121
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• 2021

세계적으로 코로나19 팬데믹이 장기화되면서 코로나19와 우울감(blue)이 합쳐진 코로나 블루(Corona Blue) 현상이 심화되고 있다. 본 연구의 목적은 코로나19 전과 후의 스트레스와 여가활동과의 연관성에 대해 알아보고, 스트레스에 따른 여가활동의 도움에 관하여 분석하는 것이다. 본 연구는 토픽모델링방법을 통한 코로나 블루 뉴스기사 분석과 설문조사의 2가지 연구방법을 활용하여 분석하였다. 즉, 첫째, 코로나19가 "경계"단계로 격상된 2020년 1월부터 사회적 거리두기 2.5단계까지 강화된 9월까지의 신문 기사를 토대로 총363건의 뉴스 기사를 토픽모델링을 통해 분석하였다. 연구 결과 총 28개의 토픽이 추출되었으며, 비슷한 주제끼리 멘탈데믹(mentaldemic), 세대확산, 우울증 가속 원인, 피로감 증가, 장기전에 대처하는 자세, 소비변화, 우울 극복을 위한 노력 총 7개로 그룹화하였다. 둘째, SPSS 통계 프로그램을 활용하여 코로나19 전, 후 여가활동에 따른 스트레스 변화수준과 여가활동에 따른 주된 도움을 분석하였다. 연구 결과 코로나19 전 여가활동 참여에 따른 스트레스 감소 평균 차이가 코로나19 후 보다 큰 것으로 확인할 수 있었으며, 코로나19 후에도 여가활동은 스트레스 완화에 효과가 있는 것으로 나타났다. 또한, 코로나 19전 여가활동에 따른 주된 도움이 신체적, 사회적 활동을 통한 기분전환, 재충전의 의미였다면, 코로나19 후에는 자연, 야외 활동, 지적 활동을 통한 기분전환, 잠깐 잊음과 같은 심리적 역할이 큰 것으로 나타났다. 결론적으로 본 연구는 코로나 블루 현황 파악과 극심한 스트레스 상황에서 여가 대처를 통해 완화 효과가 있음을 확인하였다. 본 연구 결과는 향후 코로나 블루 극복을 위한 현실적이고 바람직한 여가 정책 및 대응방안 마련에 기초 자료가 될 수 있을 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1156-1158
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• 1995

Charge decay, thermally stimulated current(TSC), charging and discharging currents(I) are measured for negatively corona-charged polymers. In this study, we will make an experiment in charge decay on polymer surface, TSC, polarity effect and the others in order to analysis it's mechanism. Especially polyvinylidene fluoride(PVDF) film is the best functional material which has been so far. Therefore, It's worthy of notice to investigate it's characteristic. And then some other functional polymers will be focused on. An experimental result was missed out for the shortage of setting. So, this thesis will be explained on the theory and direction of reseach hereafter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1574-1575
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• 2011

The application of a pulsed power system is being extended to an environmental and industrial field. The non-destructive gaseous pollutants from industrial plants such as power generation plants and incinerators can be processed by applying high voltage pulses with a fast rising time (a few nanoseconds) and short duration (nano to microseconds) in a pulsed corona discharge reactor. The pulsed plasma generator with a triggered switch has been developed. Its corona current in load can be adjusted by applied voltage and repetition rate. We investigated the performance of the pulsed plasma generator by analyzing the concentration of ozone in small reactor. This paper describes the electrical characteristics of the pulse generator with a voltage of 30 kV at repetition rate of 50 PPS. In addition, we briefly discuss a configuration of the system and initial test results.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2077-2082
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• 2015

Based on Deutsch assumption, a calculation method on the electric field over the ground surface under HVDC transmission lines in the wind is proposed. Analyzing the wind effects on the electric field and the space charge density the existing method based on Deutsch assumption is improved through adding the wind speed to the ion flow field equations. The programming details are illustrated. The calculation results at zero wind speed are compared with available data to validate the code program. Then the ionized fields which resulted from corona of ±800kV HVDC lines are analyzed. Both the electric field and the current density on the ground level are computed under different wind direction and speed. The computation results are in good agreement with measurements. The presented method and code program can be used to rapidly predict and evaluate the wind effects in HVDC transmission engineering.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.365-368
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• 1995

Charge decay, thermally stimulated current (TSC), charging and discharging currents(I) are measured for corona-charged composite insulating materials. In this study, We will make an experiment in charge decay on composite material surface, TSC, polarity effect and the others in order to analysis its mechanism. Especially, Fiber glass Reinforced Plastics(FRP) is the best composite material which has been so far. Therefore, Its worthy of notice to investigate its characteristic. And then some other materials will be focused on. This experiment measured characteristic of charge decay, dependence of discharging-time and other electrostatic characteristics on FRP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술대회 논문집 전문대학교육위원
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• pp.132-134
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• 2003

Insulator that is used in electric power equipment superannuation and being damaged disorder can. Such as defected insulator has repair or change must because defective influence in electrical equipment. There are many method developed for detecting the defected insulators, analyzed various test of devide voltage, electric field, ultrasonic and discharge pulse. But methods of detecting ultrasonic of discharge, electric field or leakage current could not application in the field, In this paper, we compare the advantage and the limitation of the method to detect defected insulator, and wish proposed using corona camera.

• 설비공학논문집
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• 제13권10호
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• pp.939-946
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• 2001

This study investigates the electrical and collection characteristics of a wide plate spacing electrostatic precipitator (ESP), using a pilot-scale one. Electrical operating characteristics and collection efficiency were measured for various shapes of discharge electrodes. The collection plate spacing ranged from 300 to 550 mm. Results of electrical characteristic and collection efficiency tests as a function of collection plate spacing, discharge electrode type, applied voltage, and particle diameter were obtained. Increasing the collection plate pitch and altering the corona electrode geometry was found to increase the collection efficiencies without increasing input power requirement. The best efficiency is achieved for the discharge electrode of twisted pin type.

• Environmental Engineering Research
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• 제11권3호
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• pp.164-171
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• 2006

Numerical modeling of the flow velocity fields for the near corona wire electrohydrodynamic (EHD) flow was conducted. The steady, two-dimensional momentum equations have been computed for a wire-plate type electrostatic precipitator (ESP). The equations were solved in the conservative finite-difference form on a fine uniform rectilinear grid of sufficient resolution to accurately capture the momentum boundary layers. The numerical procedure for the differential equations was used by SIMPLEST algorithm. The Phoenics (Version 3.5.1) CFD code, coupled with Poisson's electric field, ion transport equations and the momentum equation with electric body force were used for the numerical simulation and the Chen-Kim ${\kappa}-{\varepsilon}$ turbulent model numerical results that an EHD secondary flow was clearly visible in the downstream regions of the corona wire despite the low Reynolds number for the electrode ($Re_{cw}=12.4$). Secondary flow vortices caused by the EHD increases with increasing discharge current or EHD number, hence pressure drop of ESP increases.