• Title/Summary/Keyword: Protective Effectiveness

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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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    • 2002.11b
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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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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.

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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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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    • v.6 no.2
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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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    • v.8 no.5
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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.

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

  • Kim, Su-Nam;Lee, Jae-Gyu;Lee, Myeong-Su;Yu, Seok-Gu
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.9
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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.

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

  • Kim, K.J.;Lee, S.J.;Choi, M.S.;Kang, S.H.;Kim, H.P.;Lee, W.H.;Choi, H.S.
    • Proceedings of the KIEE Conference
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    • 1999.11b
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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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Optimal Location of a Protective Device by using Parametric Protection Ability Index (파라메터 관점의 보호능력 평가지표를 이용한 보호기기의 위치 선정)

  • Shin, J.H.;Lim, S.I.;Hyun, S.H.;Lee, S.J.;Ha, B.N.;Seol, I.H.
    • Proceedings of the KIEE Conference
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    • 2003.07a
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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
    • Biomedical Science Letters
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    • v.28 no.4
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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.

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

  • 박완제;조양제;김영지;김제학;박관하;김유삼;함경수
    • Biomolecules & Therapeutics
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    • v.2 no.4
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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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