• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.4
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• pp.276-281
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• 2008

Because the distribution systems experience frequently the fault by several causes, the identification task of fault location plays very important role in the view point of power supply reliability. The distribution systems are designed as radial structure with three-phase and single-phase branch line to supply the electric power to the widely dispersed loads, and it have a several load taps within each line segment. it makes the accurate fault distance determination difficult. Accordingly in this papers, the existing fault point determination methods are surveyed and analyzed, and then a fault distance determination method for distribution feeder is adopted which can be executed effectively in DAS center. Finally, the adopted method is verified using EMTP simulation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.31-32
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• 2007

In this paper, a fault section detection method is proposed for ungrounded system in the case of a single line-to-ground fault. A conventional method is used for faulted feeder selection according to the angular relationship between zero-sequence currents of the feeders and zero-sequence voltage of the system. Fault section detection is based on the comparison of phase angle of zero-sequence current. Proposed method has been testified in a demo system by Matlab/Simulink simulations. Based on Distribution Automation System(DAS), Feeder Remote Terminal Unit(FRTU) is used to collect those necessary data, at present a demo system is under developing using Manufacturing Message Specification (MMS) in IEC61850 standard.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.65-69
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• 2020

The aim of this study is to improve the fault decision ability of FRTU (Feeder remote terminal unit) in DAS (Distribution automation system). FRTU uses the FI (Fault indicator) algorithm based on fault current pickup and operation of the protection device. Even if the inrush current flows or the protection device is sensitive to the transient current, FRTU may indicate incorrect fault information. To address these problems, we propose an improved fault recognition algorithm that can be applied to FRTU. We will detect a specific wave that is indicative of a fault, and use this information to identify a fault wave. The specific wave-detection algorithm is based on the duration and periodicity of the voltage, current, and harmonic variations. In addition, we propose fault recognition algorithms using voltage factor variation analysis and DWT (Discrete wavelet transform). All the wave data used in this study were actual data stored in FRTU.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1463-1471
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• 2009

In this paper, a new algorithm of Integrated Volt/Var Control (IVVC) is proposed using Volt/Var control for the Distribution Automation System (DAS) based on the modeling of the distributed load and the distributed current. In the proposed, the load flow based on the modeling of the distributed load and the distributed current are estimated from constants of four terminals using the measurement of the current and power factor from a Feeder Remote Terminal Unit (FRTU). For Integrated Volt/Var Control (IVVC), the gradient method is applied to find optimal solution for tap and capacity control of OLTC (On-Load Tap Changers), SVR (Step Voltage Regulator), and SC (Shunt Condenser). What is more Volt/Var control method is proposed using moving the tie switch as well as IVVC algorithm using power utility control. In the case studies, the estimation and simulation network have been testified in Matlab Simulink.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.95_96
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• 2009

In this paper, a new algorithm of Integrated Volt/Var Control (IVVC) is proposed using Volt/Var control for the Distribution Automation System (DAS) based on the modeling of the distributed load and the distributed current. In the proposed, the load flow based on the modeling of the distributed load with Distributed Generation and the distributed current are estimated from constants of four terminals using the measurement of the current and power factor from a Feeder Remote Terminal Unit (FRTU). For Integrated Volt/Var Control (IVVC), the gradient method is applied to find optimal solution for tap and capacity control of OLTC (On-Load Tap Changers), SVR (Step Voltage Regulator), and SC (Shunt Condenser). What is more Volt/Var control method is proposed using moving the tie switch as well as IVVC algorithm using power utility control. In the case studies, the estimation and simulation network have been testified in Matlab Simulink.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.1
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• pp.5-7
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• 2022

KEPCO's plan is undergoing a trial operation to replace the open-loop section with ring main units configuration where underground distribution lines are installed, by linking the multi-way circuit breakers auto (MCA) on the power side of each pad-mounted transformer. However, ring main units application mentioned above may cause the ripple effects, when implementing the configuration without a study of protection coordination. Because ring main units with classical pre-set protection devices contribution in fault condition didn't consider yet. For the reliable ring main units operation, it is necessary to resolve several protection issues such as the protection coordination with substation side, prevention of the transformer inrush current. These issues can radically deteriorate the distribution system reliability Hence, it is essential to design proper protection coordination to reduce these types of problems. This paper presents a scheme of ring main units' configuration and MCA's settings of time-current curves to preserve the performance of protection coordination among the switchgears considering constraints, e.g. prevention of the ripple effects (on the branch section when a transformer failure occurs and the mainline when a branch line failure occurs). It was confirmed that the propagation of the failure for each interrupter segment could be minimized by applying the proposed TCC and the interrupter settings for the MCAs (branch, transformer). Further, it was verified that the undetected area of the distribution automation system (DAS) could be supplemented by having the MCA configurated ring main units operate first, instead of the internal protection equipment in the transformer such as the fuse, STP when a transformer failure occurs.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.269-272
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• 2004

1950년대 동란을 거쳐 1960년대 초반부터 시작된 경제개발계획에 의해 급격한 경제성장으로 인해 산업 인구의 대도시 집중화에 의하여 전기의 공급력 부족 현상은 지속되었다. 따라서, 이때부터 성장한 경제배전계통은 수적으로도 많고 광범위하게 산재되어 있어 인력에 의해서는 더 이상 효과적인 관리가 어렵게 되었고, 사회가 고도 정보화로 진전되면서 수용가는 한층 더 높은 공급 신뢰도와 고품질의 전력공급을 요구하고 있다. 이러한 변화에 따라 전력공급자는 전력계통에 대한 감시와 제어를 통하여 항시 안정적이고 신뢰성있는 운용을 하여야한다. 이에 따라 배전계통에 설치된 배전설비를 컴퓨터와 통신수단을 이용하여 원격지에서 감시 제어할 수 있는 배전자동화 시스템에 대한 연구가 오래 전부터 이루어져 왔으며 효과적으로 양질의 전력을 공급하고자 배전자동화 시스템(DAS)이 도입되었다. 본 연구에서는 능동적인 감시 및 제어기능을 제공하는 객체지향형 능동데이터베이스 알고리즘을 사용하여 배전계통 제어에 적용하였고 기존의 인터넷 통신망을 통한 감시 및 제어가 가능하게 하였으며 이러한 효과에 의해 배전계통이 여러개의 다른 전력회사로 분할될 경우 각기 존재하는 다른 시스템에 대하여 인터넷을 통한 연계가 가능하도록 하여 통합적인 데이터베이스를 구축하는데 용이하게 하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1_3
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• 2009

국내 내륙 전체 배전계통은 "22.9kV-Y 중성선 다중접지방식"으로 일원화하여 운영 중에 있으나 도서 섬지역은 자체 내연력 발전 설비를 갖추고 380V-Y로 발전하여 $6.6kV-{\Delta}$로 승압 후 전력을 공급하고 있다. 현재 한전은 설비용량 200kW이상 38개 도서에서 비접지 계통으로 운영 중에 있다. KEPCO와 KDN은 비접지계통($6.6kV-{\Delta}$)으로 운영중인 도서 중 전북지사 부안지점 관내 위도에 시범운영을 통해서 실선로에서 비접지 1선 지락 고장 검출여부 검증을 시행하였다. 시범운영에는 배전자동화 시스템 주장치 1식, mFRTU 12대를 개폐기와 같이 설치하였는데, mFRTU에는 독창적이고 상용화 가능한 "비접지 지락고장검출 알고리즘" 개발하여 탑재하였으며 1선 지락고장을 발생시켜 mFRTU가 고장선로와 고장지점을 정확하게 검출하는지 여부를 검증하였다. 이번에 비접지계통 실선로에서 지락고장을 완벽하게 검출한 가장 큰 의의는 국내 및 해외 최초로 비접지 지락고장검출을 성공하였다는 것입니다. 본 논문에서는 비접지로 운영중인 도서지역에 배전자동화시스템 기반으로 지락고장검출하는 기능을 상용화하여 운영중인 시스템에 대한 내용이다. 이번에 구축한 배전자동화시스템은 비접지계통에 알맞도록 개발된 자동화용 개폐기와mFRTU에 지락고장검출 알고리즘을 기능 구현하였다. 선로에 1선지락 고장발생시 mFRTU가 고장선로, 고장구간 및 고장상 등을 판단하고 상위 주장치에 전송한다. 주장치는 고장정보를 HMI 단선도에 고장지점을 표시하여 종합적으로 감시제어 할 수 있는 시스템이다.