• Title/Summary/Keyword: Protective Effectiveness

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A Protective Effectiveness Measure for Distribution Systems (배전계통 보호시스템의 보호능력의 평가방법)

  • 현승호;이승재;임성일;최인선;신재항;최면송
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.5
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    • pp.249-256
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    • 2004
  • This paper suggests a novel evaluation scheme of protective effectiveness in distribution systems. The adequacy of every parameter in a protective device is evaluated for the setting or correction rules. Then, the protective effectiveness of a device, device-wise effectiveness, is obtained by the combination of the parametric evaluation results. The coordination-wise effectiveness between devices can be calculated by evaluating the parameters which contribute the performance of coordination. The protective effectiveness of the whole system can be obtained by combining the device-wise and coordination-wise effectiveness values. The rules, in this paper, are categorized into three groups; rules for single parameter, rules for coordination between parameters, and rules for coordination between protective devices to form a hierarchical calculation model. The proposed method is applied to a typical distribution network to show its effectiveness.

The Effectiveness due to fixed position change of fault protective wire on catenary system (전차선로에서 보호선 설치 위치변경에 따른 효과 검토)

  • Ryoo, Hyang-Bok;Ahn, Young-Hoon;Hyun, Chung-Il;Kang, Seung-Wook
    • Proceedings of the KSR Conference
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    • pp.1456-1459
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    • 2007
  • Protective equipments have a very important protection role in power accident on catenary line. These equipments are installed on electrical pole. The poles have complicated with many bands(moveable bracket, branch wire anchor, shield wire, etc). So we have improved bands and installed bands on pole to test technical condition. The Result has showed effectiveness due to fixed position change of fault protective wire and to improve band shape. For example, reduction of band made cost, simplification of installing, correct position of protective wire and shield wire.

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A Study on the Effectiveness of Protective Capacity in a Re-entrant Line (재투입 생산라인에서 방어적 생산능력의 효과성에 관한 연구)

  • 김선민;강현곤
    • Korean Management Science Review
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    • v.17 no.1
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    • pp.17-30
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    • 2000
  • This paper addresses the effect of protective capacity on the lead time and throughput of a re-entrant line where statistical fluctuations exist in the form of variation in processing times and machine breakdowns. The specific framework employed in the paper is a five station re-entrant line structured as a closed network mode. This paper argues that protective capacity can be used in conjunction with WIP inventory in order to reduce the lead time and to increase the increase the throughput of a line. Simulation analyses are included to give insight into the effectiveness of protective capacity.

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Electromagnetic Pulse Shielding Effectiveness and Construction Availability of Cast-In-Place Structures Using Corrugated Metal-Plates

  • Kim, Suk Bong;Yoon, Sangho;Min, Gyung Chan;Ahn, Sungjin;Park, Young Jun
    • Journal of the Korea Institute of Building Construction
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    • v.13 no.1
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    • pp.84-89
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    • 2013
  • This study aims to examine the effectiveness of electromagnetic pulse shielding in cast-in-place protective shelters using corrugated metal-plates, and then reviews their usability for the Republic of Korea Army. The Korea Corps of Engineering has evaluated corrugated metal-plates as a construction material for cast-in-place structures, which have to defend against mechanical impacts as well as electromagnetic pulses. Corrugated metal-plate is known as a superb mechanical protective material, so much so that it has been employed in ammunition magazines and artillery platforms in the armed forces. Moreover, as a metal, such as steel and copper, it is universally recognized as one of the most effective electromagnetic pulse shielding materials. In addition to effectively shielding from electromagnetic pulses and protecting against mechanical impacts, corrugated metal-plates should prove to be an appropriate construction material for the cast-in-place protective shelter in terms of construction availability and economic feasibility. The shielding effectiveness of the suggested structures is examined based on MIL-STD 188-125-1. A few frequency bands need an increase of 15~30dB in shielding effectiveness because of unbidden apertures caused by flaws associated with welding, assembling, and material deformation. However, allowing for the approximately 40dB of shielding provided by soil; the examined structure, which is buried underground, can offset its shortcomings sufficiently.

Utility of Wearing Protective Apron for X-ray of Thick Subject (두꺼운 피사체 X선 촬영 시 보호앞치마 착용의 유용성)

  • Choi, Seong-Kwan;Dong, Kyung-Rae
    • Journal of Radiation Industry
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    • v.11 no.3
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    • pp.167-171
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    • 2017
  • This study examined the effectiveness degree of a protective apron that is taken not to be exposed to the first ray or scattered rays, for X-ray of thick subject like lateral lumbar, and the results are as follows; First, spatial dose by scattered rays is shielded by 3 mmPb protective apron, 86.8% at a distance of 50 cm, 92.7% at 100 cm, and 95.6% at 200 cm, when minimizing the field size, while 89% at a distance of 50 cm, 92.3% at 100 cm, and 95.2% at 200 cm, when maximizing the field size. Second, 1st exposure dose is shielded by 3 mmPb protective apron, 93.7% at a distance of 50 cm, 94.4% at 100 cm, and 93.6% at 200 cm, when minimizing the field size, while 93.7% at a distance of 50 cm, 93.6% at 100 cm, and 94.2% at 200 cm, when maximizing the field size.

A Study on the Protective Coordination of Distribution Automation System under Loop Operation (배전자동화 계통의 루프 운전시 보호협조에 관한 연구)

  • Lee, Hee-Tae;Moon, Jong-Fil;Kim, Jae-Chul
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.7
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    • pp.1281-1286
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    • 2009
  • As a general radial configuration of power distribution system, the various researches have being studied to change a radial configuration to network one such as smart, intelligent and micro grid for loop operation. If a radial configuration changes to network, protective coordination comes to the biggest problem. When a typical protective algorithm is applied to loop distribution system protection, the interrupted section is expanded, therefore, reliability grows worse. This paper presents the new protective method being able to apply to loop distribution system with Distribution Automation System (DAS) which separate the minimal faulted section. Through contingency analysis of the sustained and momentary fault, we analyzed the influence for radial configuration and loop configuration using interrupted area and proved the effectiveness of proposed method.

An Exploratory Study on Domestic and International Protective Clothing Standard - Focused on ISO, ASTM, CEN, KS - (보호복 관련 국내·외 표준에 대한 탐색적 조사 - ISO, ASTM, CEN, KS를 중심으로 -)

  • Han, Sul-Ah;Nam, Yun-Ja
    • Fashion & Textile Research Journal
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    • v.10 no.1
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    • pp.92-100
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    • 2008
  • When designing protective clothing, there are something to be considered such as physiological feature of human body, acting range not to restrict physical activity, and effectiveness of material. Because the primary objective of protective clothing is to protect human body from danger and it is designed through complex designing process not likely general clothing design. However, current evaluation techniques-such as the ISO, the ASTM and the CEN, and KS-provide only the standard to evaluate the primary feature of material (testing, performance requirements, material specification, selection and application, test and care, and so on). There are no standard to evaluate influence for the human body while protective clothing put on. Especially, in Korea, there is KS to evaluate protective clothing, but it is partially translated version from ISO because of lack of core technology about this field. However, developed countries recognize it is new competitive means in the time of Global Standards and they are competing to make their own standard to global standard for the protective clothing. Therefore, it can be great opportunity for Korean clothing and textile industry to revitalize if focusing on research and development for protective clothing design based on physical activity of human body, fit evaluation technique and sizing which is currently no global standard for it and developing our standard to global standard.

Parametric Evaluation Method of Protectability in a Distribution System (파라메터 관점에서의 배전계통 보호도 평가방법)

  • Cho, P.S.;Hyun, S.H.;Lim, S.I.;Lee, S.J.;Lee, D.S.;Waldemar, Waldemar
    • Proceedings of the KIEE Conference
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    • pp.241-243
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    • 2002
  • Recently, great efforts are concentrated on the autonomous, adaptive protection schemes with advanced artificial intelligence and digital technology. It is highly required for a next generation protective system not only to detect and to clear a fault, but also to fit itself to the changing environment. In this paper it is suggested an evaluation method for the protection ability of a protective system in a distributed system. The suggested method is of bottom-up scheme, in other words, protection ability is estimated from the lowest level of parameters in each protective devices to the highest level of the whole protective system. This feature makes it possible to evaluate the protection ability either for the protective device(or a system), or for a protected system. And, in addition, it is enabled that the protectability concept can be applied in the design stage of a protective system for a distribution network. The proposed method is applied to a simple distributed network to show its effectiveness.

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The Effects of Emotional Factors on Environment Behaviors - Comparing the Protective Motivation Theory with the ERB-Based Tentative Model - (환경행동에 미치는 정서적 요인의 영향: -보호동기이론과 환경 책임성 행위모형에 근거한 잠정적 모형의 비교-)

  • 이태연
    • Hwankyungkyoyuk
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    • v.15 no.1
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    • pp.18-30
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    • 2002
  • So far, the environmentally responsible behavior(ERB) model has been applied successfully to explain environment behaviors. But the ERB model has several limitations such as underestimation of social factors on environment behaviors. This study planned to point out that the emotional aspects should be considered seriously for explaining human's behaviors to conserve the environment in the ERB model. In this study, the effects of emotional aspects, such as perceived severity or perceived danger, on environment behaviors were investigated and the protective motivation theory(Rogers, 1983) and the ERB-based tentative model were compared Results showed that teenagers in urban areas realized clearly the severity and danger of environmental threats and do environmentally responsible behaviors more than ones in rural areas. Two model's goodness of fit to explain observed environment behaviors were analyzed through the regression analysis and the AMOS analysis. In the regression analysis, self-efficacy, confirmity toward social norm, and knowledge were involved in the regression equation as statistically meaningful variables in the ERB-based tentative model and self-efficacy and perceived severity were involved in the protective motivation theory. Especially, the AMOS analysis showed that the protective motivation theory was more valid model lot explaining environment behaviors than the ERB-based tentative model. In conclusion, it is reasonable that emotional aspects should be considered as meaningful variables for explaining environment behaviors.

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A Study on the Optimal Method for Mal-function of Re-closer at the Distribution Feeders Interconnected with PV Systems (태양광발전이 연계된 배전계통의 보호기기 오동작에 대한 최적 운용방안에 관한 연구)

  • Kim, Chan-Hyeok;Park, Hyeon-Seok;Rho, Dea-Seok;Shin, Chang-Hoon;Yoon, Gi-Gab
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.8
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    • pp.1512-1518
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    • 2009
  • Recently, new dispersed power sources such as photovoltaics, wind power, fuel cell etc. are energetically interconnected and operated in the distribution systems, as one of the national projects for alternative energy. This paper deals with the optimal countermeasures for the mal-function of protective devices at primary feeder in distribution systems when new power sources like photovoltaic (PV) systems are interconnected, based on the symmetrical components of short circuit studies. When new power sources are considered to be interconnected to distribution systems, bi-directional power flow and interconnection transformer connection of new power sources may cause the operation problems of protective devices (mainly re-closer), since new power sources can change typical characteristics of distribution systems. Therefore, this paper shows an analysis skill of the mal-functional mechanism of protective relay and proposes the optimal solution for the mal-function problem using the symmetrical components of fault analysis. And, this paper also shows the effectiveness of proposed method by the simulation at the field distribution systems.