• 제목/요약/키워드: Protective Effectiveness

검색결과 156건 처리시간 0.022초

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

  • 조필성;현승호;임성일;이승재;이덕수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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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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태양광발전이 연계된 배전계통의 보호기기 오동작에 대한 최적 운용방안에 관한 연구 (A Study on the Optimal Method for Mal-function of Re-closer at the Distribution Feeders Interconnected with PV Systems)

  • 김찬혁;박현석;노대석;신창훈;윤기갑
    • 전기학회논문지
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    • 제58권8호
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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.

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

  • 이태연
    • 한국환경교육학회지:환경교육
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    • 제15권1호
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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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Development of an Impedance Locus Model for a Protective Relay Dynamic Test with a Digital Simulator

  • Kim, Soo-Nam;Lee, Myoung-Soo;Lee, Jae-Gyu;Rhee, Sang-Bong;Kim, Kyu-Ho
    • Journal of Electrical Engineering and Technology
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    • 제6권2호
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    • pp.167-173
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    • 2011
  • This paper presents a method for the development of the impedance locus to test the dynamic characteristics of protective relays. Specifically, using the proposed method, the impedance locus can comprise three impedance points, and the speed of impedance trajectory can be adjusted by frequency deviation. This paper is divided into two main sections. The first section deals with the configuration of impedance locus with voltage magnitude, total impedance magnitude, and impedance angle. The second section discusses the control of the locus speed with the means of the deviation between two frequencies. The proposed method is applied to two machine equivalent systems with offline simulation (i.e., PSCAD) and real-time simulation (i.e., real-time simulation environment) to demonstrate its effectiveness.

Adaptive Protection Algorithm for Overcurrent Relay in Distribution System with DG

  • Sung, Byung Chul;Lee, Soo Hyoung;Park, Jung-Wook;Meliopoulos, A.P.S.
    • Journal of Electrical Engineering and Technology
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    • 제8권5호
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    • pp.1002-1011
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    • 2013
  • This paper proposes the new adaptive protection algorithm for inverse-time overcurrent relays (OCRs) to ensure their proper operating time and protective coordination. The application of the proposed algorithm requires digital protection relays with microcontroller and memory. The operating parameters of digital OCRs are adjusted based on the available data whenever system conditions (system with distributed generation (DG)) vary. Moreover, it can reduce the calculation time required to determine the operating parameters for achieving its purpose. To verify its effectiveness, several case studies are performed in time-domain simulation. The results show that the proposed adaptive protection algorithm can keep the proper operating time and provide the protective coordination time interval with fast response.

보호 계전기 동특성 테스트를 위한 임피던스 궤적 모델 개발 (Development of Impedance Locus Model for Protective Relay Dynamic Test)

  • 김수남;이재규;이명수;유석구
    • 대한전기학회논문지:전력기술부문A
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    • 제51권9호
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    • pp.451-459
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    • 2002
  • This paper presents a method for modelling of the impedance locus in order to test the protective relay with dynamic. This paper has the two parts, the first part is the configuration of impedance locus with voltage magnitude, total impedance magnitude and angle. And the second part is the control of the locus speed with deviation of two frequencies. The proposed method is applied to two machine equivalent system with PSCAD/EMTDC to show its effectiveness.

송전계통 선로보호 계전기 동작 진단 시스템 (A Development of Protective Relay Operating-Diagnosis System for Power System)

  • 김국진;이승재;최면송;강상희;김호표;이운희;최홍석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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    • pp.107-109
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    • 1999
  • In the point of view protective relay, the selectivity and sensitivity is very important in its performance. The correct setting of the relay parameter is required. The verification of accurate setting for the protective relay is very difficult before a actual fault occurs. In this paper, we proposed the diagnosis expert system as a method to verify the correctness of the relay setting. The developed system proved effectiveness through the tests on the real systems.

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파라메터 관점의 보호능력 평가지표를 이용한 보호기기의 위치 선정 (Optimal Location of a Protective Device by using Parametric Protection Ability Index)

  • 신재항;임성일;현승호;이승재;하복남;설일호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.366-368
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    • 2003
  • In this paper, a parametric evaluation method of protection ability is proposed. The adequacy of every parameter is evaluated for the setting rules. Then the results are combined to give protection level of a whole protective system. The setting rules are categorized into three groups for hierarchical calculation. The proposed scheme is applied to a location problem of a new protective device to show its effectiveness.

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Protective Effect of Aqueous Extract from Erigeron annuus Against Cell Death Induced by Free Radicals

  • Myeongguk Jeong;Hyeokjin Kwon;Youngdon Ju;Go-Eun Choi;Kyung-Yae Hyun
    • 대한의생명과학회지
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    • 제28권4호
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    • pp.307-311
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    • 2022
  • The extract of EA lacks studies showing its efficacy other than that it contains caffeic acid, an active compound that has antioxidant and neuroprotective effects on nerve cells. Therefore, in this study, we attempted to determine the effectiveness of EA extraction. In this study, we performed a DPPH assay to determine the antioxidant potential of EA. And then, the cytotoxic concentration of EA in HaCaT keratinocytes was determined, and the antioxidant effect was determined by measuring the malondialdehyde (MDA). The results of DPPH, a chemical antioxidant assay, clearly demonstrated the antioxidant capacity of EA extracted with distilled water. In addition, cell-based assays provide useful information on the protective effect of EA on oxidative stress-induced apoptosis.

CFC-101(녹농균 백신)의 능동 및 수동면역 효과 (Active and Passive Protective Effect of CFC-101 (Pseudomonas Vaccine) in Mice)

  • 박완제;조양제;김영지;김제학;박관하;김유삼;함경수
    • Biomolecules & Therapeutics
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    • 제2권4호
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    • pp.326-330
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    • 1994
  • The treatment of pseudomonal infection is a perplexed problem because of its modest susceptibility to most of the major antibiotics. A novel Pseudomonas vaccine(CFC-101) was prepared from the outer membrane protein fractions of several Pseudomonas strains. In this study, we examined CFC-101's effectiveness in both active and passive immunization models. CFC-101 in mice at 0.2 mg/kg, i.p., given three times at two-day intervals, completely prevented the death caused by Pseudomonas aeruginosa. Antibody titer, in accordance with the protective effect in this active immunization, was elevated to its peak level following three consecutive administrations of CFC-101. Thereafter, antibody titer stayed at a constantly high level. Each outer membrane protein fraction from the four CFC-101 producers, exhibited good cross-protective effects in mouse infection models against different Fisher types of P. aeruginosa. In the passive immunization model, 21~336 $\mu\textrm{g}$/kg of anti-rabbit IgG to CFC-101, when mice being infected with a challenge strain, prevented the Pseudomonhas-induced death up to 60%. Therefore, the preventive effect of CFC-101 was verified in both the active and passive immunization models.

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