• Title/Summary/Keyword: Reclosing

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Impact of auto-reclosing on Customer systems (재폐로에 의한 수용가측의 영향)

  • Rim, Seong-Jeong;Oh, Jung-Hwan;Kim, Jae-Chul;Kim, Il-Dong;Han, Kyung-Nam;Kim, Yeong-Han
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.740-742
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    • 1996
  • This paper analyzes the Impact of customer system at the transients due to auto-reclosing on 22.9kV distribution lines. The various factors affecting this phenomena are analyzed In detail through parametric studies. These factors Include the fault current, fault location, reclosing angle, capacitor bank size, and customer load characteristics. The impacts of these transients on customer system are described and available to identify the optimal auto-reclosing scheme.

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A Novel AC Solid-State Circuit Breaker with Reclosing and Rebreaking Capability

  • Kim, Jin-Young;Choi, Seung-Soo;Kim, In-Dong
    • Journal of Power Electronics
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    • v.15 no.4
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    • pp.1074-1084
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    • 2015
  • These days, the widespread use of sensitive loads and distributed generators makes the solid-state circuit breaker (SSCB) an essential component in power circuits to achieve a high power quality for AC Grids. In traditional AC SSCB using SCRs, some auxiliary mechanical devices are required to make the reclosing operation possible before fault recovery. However, the proposed AC SSCB can break quickly and then be reclosed without auxiliary mechanical devices even during the short-circuit fault. Moreover, its fault current breaking time is short and its SSCB reclosing operation is fast. This results in a reduction of the economic losses due to fault currents and power outages. Through simulations and experiments on short-circuit faults, the performance characteristics of the proposed AC SSCB are verified. A design guideline is also suggested to apply the proposed AC SSCB to various AC grids.

Modelling of Secondary Arc Using EMTP-RV (EMTP-RV를 이용한 2차 아크 모델링)

  • Oh, Yun-Sik;Kang, Sung-Bum;Seo, Hun-Chul;Kim, Chul-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.7
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    • pp.937-943
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    • 2012
  • Most of faults occurred in transmission lines are single-phase to ground faults and transient faults. Single-phase auto reclosing is an appropriate scheme to maintain the system stability and restore the system effectively when those faults are occurred. In single-phase auto reclosing scheme, the secondary arc is generated after faulted phase is tripped to eliminate the fault and it is sustained by the capacitive and inductive coupling to the healthy phases. It is important to reclose the faulted phase after fully extinction of secondary arc because of the damage applied to system. Therefore, it is necessary to research on the detection of secondary arc extinction to ensure high success rate of reclosing. In this step, firstly, the accurate modelling of secondary arc should be performed. In this paper, the modelling of secondary arc is performed by using EMTP-RV and the simulation results show that the implemented model is correct and effective.

Study of rate of change of frequency by Reclosing and Load shedding (부하차단과 재폐로 동작에 따른 주파수변화율 크기 분석)

  • Lee Jae Wook;Park Chul Woo;Jang Byung Tae;Song In Jun;Jang Moon Seop;Kwak No Hong
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.397-399
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    • 2004
  • A small-sized isolated 154kV transmission system could be brought out by a separation from whole network due to faults at transmission lines. For such system, where a fault occurs following a reclosing action, we Provided the basis for study to provide an effective load shedding scheme needed to the case of failure of reclosing action as well as the characteristic of reclosing action whether it succeeds or fails.

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The Arcing Faults Simulation and Adaptive Autoreclosure Strategy for 765 kV Transmission Line Protection (765 kV 송전선로 보호를 위한 아크사고 시뮬레이션 및 적응적 자동재폐로 대책)

  • Ahn, Sang-Pil;Kim, Chull-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.11
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    • pp.1365-1373
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    • 1999
  • In many countries including Korea, in order to transmit the more electric power, the higher transmission line voltage is inevitable. So, a rapid reclosing scheme is important for EHV/UHV transmission lines to ensure requirements for high reliability of main lines. A critical aspect of reclosing operation is the extinction of the secondary arc since it must extinguish before successful reclosure can occur. Therefore the accurate simulation techniques of arcing faults are of importance. And successful reclosing switching can be accomplished by adopting a proper method such as HSGS and hybrid scheme to reduce the secondary arc extinction time. First of all, this paper discusses a suggested arc model, which have time dependent resistance for primary arc and piecewise linear approximated arc model for secondary arc. And this simulation technique is applied to Korean 765 kV transmission lines. Also hybrid scheme is simulated and evaluated for the purpose of shortening dead time. For adaptive reclosing scheme, variable dead time control algorithm is suggested. Two kinds of algorithm are tested. One is max tracking algorithm and the other is rms tracking algorithm. According to simulation results, rms tracking has less errors than max tracking. Therefore rms tracking is applied to Korean 765 kV transmission lines with hybrid scheme.

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A Study on the Safety of Organic Compound Type Thermal Fuse (유기물가용체형 온도퓨우즈의 안전성에 관한 연구)

  • 황명환;정영식
    • Journal of the Korean Society of Safety
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    • v.11 no.1
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    • pp.53-59
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    • 1996
  • To protect the damages or the disasters caused by overheating of industrial electric equipments or electric home appliances, a temperature sensitive thermal fuse is generally used in those equipments. Thermal fuses cutoff the current flow when the temperature of the electric equipments are abnormally overheated and over the certain temperature. Therefore thermal fuse is one of the most important elements in the sense of safety. Thermal fuses are classified into two types according to thermally sensitive materials, a low temperature melting alloy and an organic chemical compound. Domestic products of thermal fuses are now only with an organic chemical compound. Domestic products tested by using cutoff test and aging test etc. are satisfied UL specification. It's shown that the accuracy and the precision of the domestic products are as good as those of the overseas products obtained UL mark. However, some of domestic products show the reclosing problem which is mainly related the safety. This problem should be solved to make the reliable thermal fuses. In this paper, our Interest is to find out the causes of reclosing. In the comparison between thermally sensitive materials occurred reclosing and those occurred no reclosing, the test effects show that the characteristics of emitting heat and absorbing heat are different.

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Switching Surge Analysis and Evaluation in Combined Transmission System with 345kV GIL (345kV급 가공송전선로와 GIL이 연계된 혼합송전계통에서 개폐과전압 해석 및 검토)

  • Jang, Hwa-Youn;Lee, Jong-Beom;Kim, Yong-Kap;Jang, Tae-In
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.10
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    • pp.1811-1816
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    • 2011
  • This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with GIL. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as charging rate, inserting resistance, arrester, length ratio of power cable section, grounding resistance, etc. Analysis is performed by EMTP/ATP.

Development of new reclosing scheme considering the superconducting fault current limiter (초전도 한류기를 고려한 재폐로 차단기 동작 scheme 개발)

  • Ko, Yun-Tae;Seo, Hun-Chul;Rhee, Sang-Bong;Kim, Chul-Hwan;Kim, Jae-Chul;Hyun, Ok-Bae
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.135_136
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    • 2009
  • This paper proposes the new reclosing scheme considering the recovery time of SFCL in distribution systems which is based on variable dead time control. The main idea is that it uses the carrier signal to distinguish whether the fault is instantaneous or permanent following initial recloser opening. The system and SFCL is modeled by using Electromagnetic Transient Program(EMTP) and the validity of the reclosing scheme represented in this paper is analyzed according to the value of the fault resistance and the time of the fault removal.

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A Novel Algorithm for Reducing Restoration Time in Smart Distribution Systems Utilizing Reclosing Dead Time

  • Hussain, Akhtar;Choi, Myeon-Song;Lee, Seung-Jae
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.1805-1811
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    • 2014
  • After an occurrence of a fault in any distribution system, it is desired to limit the effects of the fault to smallest possible area and restore the un-faulty areas as soon as possible. Due the advancements in communication technologies, this task can be achieved in multiple efficient ways. In order to decrease the restoration time in the Smart Grid Distribution Management System (SDMS) a communication based algorithm is proposed in this paper, in which the restoration can be done during reclosing. This paper also analyzes various communication failures with power failures cases including the entire network of communication failures. Results of all these cases have been verified by doing simulations.

Calculation of Reclosing Dead Time of 500 kV Horizontal Single Circuit Transmission Line (500 kV 수평배열 1회선 송전선로의 재폐로 무전압시간 산정)

  • Shim, E.B.;Kwak, J.S.;Joo, H.J.;Park, H.S.;Kang, Y.W.
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.641-643
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    • 2005
  • It is usual to operate the long transmission line with transposition of each phase in order to avoid voltage unbalance due to unbalanced capacitances at each phase of the line end. This paper described the Ferranti voltage rise of line end, charging current and secondary arc current according to the transposition of line or not. The positive and negative sequence current was derived by the phase current, and then the unbalanced rate was calculated. Then, we obtained the reclosing dead time of the single phase reclosing scheme for 500 kV single circuit horizontal arrangement transmission line system.

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