• 제목/요약/키워드: Protective device

검색결과 271건 처리시간 0.032초

냉각 송풍장치를 이용한 기능성 농약방제복의 구성시안 제안에 관한 연구 (A Draft Proposal for Functional Pesticide Protection Clothing Using a Cooling Blower Unit)

  • 오영순;이경숙;채혜선;김경란
    • 한국지역사회생활과학회지
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    • 제25권4호
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    • pp.557-566
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    • 2014
  • This study examines he trend in the development of protective clothing for pesticide spraying based on materials with domestic patents and proposes pesticide protection clothing using a cooling blower unit effective for reducing heat stress in pesticide spraying. There was a total of 54 domestic patents on protective clothing related to pesticide spraying, reflecting a sharp increase based on the increasing demand for protective clothing since 2000. Protective clothing with a lower level of heat stress as the core technology accounted for 35.2% of these patents, and recent years have witnessed the increased development of protective clothing supplying cold air to the interior of the clothing through a separate device. However, this may cause some inconvenience in the activity of farmers. Therefore, this study proposes a lightweight cooling blower unit that does not hinder the user's appearance and activity. In the cooling blower unit, contaminated air from outside is purified through a filter and cools down as it passes a cooling device with refrigerant in the copper pipe. This chilled air is supplied to the interior of the clothing through a bidirectional inhaling blower. The proposed protective clothing is an overall with raglan sleeves. Its chill injection site has an area where the most conspicuous change in temperature is selected, and at the back, there is a large pocket for a cooling blower unit.

다수 분산전원 연계시 계통측 보호협조에 관한 연구 (The Study on Protective Coordination of Utility Interconnected Multiple Distributed Generations)

  • 정승복;김재철;이봉이
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2004년도 학술대회 논문집
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    • pp.233-235
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    • 2004
  • This paper studies protective coordination of utility interconnected multiple distirbuted generations(DG). The study of protective coordination interconnected DG has been conducted. A protective coordination of utility disturbed by reverse current of DG. Therefore, A protetive device is not operate when reverse current flows. In this paper, we use phase difference between V and I. Also, we studied protective coordination algorithm of utility interconnected multiple DG.

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도시철도 직류 비접지 급전계통에서의 선택 지락보호시스템의 성능평가 (An Evaluation of Selective Grounding Fault Protective Relaying Technique Performance on the Ungrounded DC Traction Power Supply System)

  • 정호성;김주욱;신승권;김형철;안태풍;윤준석
    • 전기학회논문지
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    • 제61권12호
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    • pp.1964-1969
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    • 2012
  • This paper presents to verify the selective grounding fault protective relaying technique for the ungrounded DC traction power supply system. This system selectively blocks fault section when grounding fault occurred. In order to perform this verification, field test facilities have been installed on Oesam substation and Worldcup-Stadium substation, and field test process has been suggested. Also, selective grounding fault protective relaying components and rail voltage reduction device have been tested with the various trial examinations. In order to compare and evaluate performance of the selective grounding fault protective relaying function, field test system was modeled and the system fault simulation results were compared and evaluated with the field test result. Performance of selective grounding fault protective relaying function was evaluated with the above-mentioned process, and the fact that the system recognizes fault section irrespective of insulation between rail and ground and fault resistance from grounding fault.

분산전원이 연결된 22.9[kV] 배전계통의 양방향 보호기기 실증시험 연구 (The Study on the Actual Examination of the Bidirectional Protection Device in the 22.9[kV] Distribution Power System Interconnected with the DG)

  • 이흥재;최명호
    • 조명전기설비학회논문지
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    • 제25권10호
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    • pp.102-108
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    • 2011
  • The existing power flow has a single direction to the line end but the bidirectional power flow will possibly occur depending on the output capacity in the 22.9[kV] distribution power system connected with the dispersed generation(DG). So these characteristics would influence the power system management. The DG have many advantages such as assistance source, Load share etc. So the utility must apply the bidirectional protection system so as to maximize an advantage of DG. This paper describes the field test case of bidirectional protective device in order to investigate the device performance when applied to bidirectional power system. We have tested in the power system test site of KEPCO and these tests provide the basis for performance verification test of bidirectional protective device in the power system.

A New Mail Survey Method for Sensitive Character without Using Randomization Device

  • Ki Hak Hong
    • Communications for Statistical Applications and Methods
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    • 제4권3호
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    • pp.735-741
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    • 1997
  • In the present paper, we propose a new randomization device free mail survey method. The estimator based on proposed model is unbiased and more efficient than the estimator based on SIngh, Mangat and Singh model (SMS-model)(1993) when $\pi$<1/2, and more protective than SMS-model in view of the protection of privacy regardless of the values of $\pi$ and $\pi_Y$ only if we count the number of say 'Yes' from the respondents. However, If we consider the respondents that say 'No', the SMS-model is more protective than our model.

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DC 급전시스템의 지락보호계전시스템 개발 (Development of Ground Fault Protective Relaying Schemes for DC Traction Power Supply System)

  • 정상기;정락교;조홍식;이안호;권삼영
    • 대한전기학회논문지:전력기술부문A
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    • 제54권9호
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    • pp.427-433
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    • 2005
  • In DC tracking power supply system, ground faults are currently detected by the potential relay, 64P. Though 64P relay detects ground fault, it cannot Identify the faulted region which causes long traffic delays and safety problem to passengers. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. One is bus differential protective relay and the other is ground overcurrent protective relay. Both type of relays is similar in principle to the ordinary bus differential protective relay and the ground overcurrent relay used in other power system. In DC traction power supply system, since it is ungrounded, ground fault current is not big enough to operate those relays. To solve the problem, a current control device, called device 'X', is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. Algorithms for these relays are developed and their validity are verified by EMTP simulation.

주상변압기 과부하 및 고장보호장치 개발에 관한연구 (A study for the overload and fault protective device of pole transformers)

  • 최봉일;임창호;김창경;김영래;송일근
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1992년도 하계학술대회 논문집 A
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    • pp.67-69
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    • 1992
  • This paper presents the new protective device which is developed specifically for use in oil filled distribution transformers. This device is mounted Inside of the transformer and connected between the secondary winding and the secondary bushings. It provides both fault and overload protection to the transformer, and visual warning of the existence of uneconomical loading conditions. It Is available in thermal/magnetic operating device depending upon fault duty required.

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Reconstruction Characteristics of MgO (111) Textured Protective Layer by Over-Frequency Accelerated Discharge in AC Plasma Display Pannel

  • Kwon, Sang-Koo;Kim, Jeong-Ho;Moon, Seung-Kyu;Kim, Hyun-Ha;Park, Kyu-Ho;Kim, Sung-Tae
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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    • pp.224-227
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    • 2007
  • The reconstruction characteristics of MgO (111) textured protective layer by over-frequency accelerated discharge in AC-PDP were investigated and correlated to the variations of electronic structures. The reconstruction process and exaggerated grain growth (EGG) were explained by defect-assisted 2-D nucleation and growth mechanism combined with charged cluster model.

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LTCC 보호층 형성에 따른 박막 전극패턴에 관한 연구 (Effect of Protective layer on LTCC Substrate for Thin Metal Film Patterns)

  • 김용석;유원희;장병규;박정환;유제광;오용수
    • 한국재료학회지
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    • 제19권7호
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    • pp.349-355
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    • 2009
  • Metal thin film patterns on a LTCC substrate, which was connected through inner via and metal paste for electrical signals, were formed by a screen printing process that used electric paste, such as silver and copper, in a conventional method. This method brought about many problems, such as non uniform thickness in printing, large line spaces, and non-clearance. As a result of these problems, it was very difficult to perform fine and high resolution for high frequency signals. In this study, the electric signal patterns were formed with the sputtered metal thin films (Ti, Cu) on an LTCC substrate that was coated with protective oxide layers, such as $TiO_2$ and $SiO_2$. These electric signal patterns' morphology, surface bonding strength, and effect on electro plating were also investigated. After putting a sold ball on the sputtered metal thin films, their adhesion strength on the LTCC substrate was also evaluated. The protective oxide layers were found to play important roles in creating a strong design for electric components and integrating circuit modules in high frequency ranges.