• 한국초전도학회:학술대회논문집
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• v.10
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• pp.268-271
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• 2000

We simulated the current limiting characteristics of a resistive SFCL with 16 ${\Omega}$ of resistance for a single line-to-ground fault in the 22.9 kV system. The transient current during the fault increased up to 6.33 kA, 5.80 kA and 3.71 kA without SFCL at the fault angles of 0${\circ}$,45${\circ}$ and 90${\circ}$, respectively. An resistive SFCL limited the fault current to 2.27 kA in a half cycle. The quench resistance of 16 ${\Omega}$ was suggested to be appropriate to limit the fault current in the 22.9 kV distribution system.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.152-156
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• 2007

This paper proposes a method for real-time control of both capacitors and ULTC in a distribution system to reduce the total power loss and to improve the voltage profile over the course of a day. The multi-stage consists of the off-line stage to determine dispatch schedule based on a load forecast and the on-line stage generates the time and control sequences at each sampling time. It is then determined whether one of the control actions in the control sequence is performed at the present sampling time. The proposed method is presented for a typical radial distribution system with a single ULTC and capacitors.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1034-1035
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• 2015

Watertight 25.8 kV/600 A/12.5 kA fault current limiters (FCLs) have successfully installed in five areas (Incheon, Seoul, Gyeong-gi, Daejeon, Suwon) on KEPCO power distribution line for the purpose of commercial demonstrations. The fault current limiting operation of this FCL, which includes functions of sensing, commutation, and reduction of fault currents, is perfectly completed within 1 cycle immediately after fault occurs. The performance of FCL was verified by short circuit test, impedance test, insulation test, temperature-rise test, and control test, etc at PT&T in LS industrial systems, which is the official certification institute in Korea. In 2013, and also the FCL field test was performed in order to test the protection coordination between conventional relays and FCL, on the 1.5 kA and 5.0 kA faults, which were made by connecting the Artificial Fault Generator (AFG) to the distribution line in test grid at KEPCO Power Testing Center. The next step of this project is to check the FCL conditions caused by real external environment, and acquire the various data from five regions installed with FCL. In this paper, we intend to explain the FCL specifications and performance characteristics, and check the expected effect by application of FCL to power distribution line based on the power system analysis of an application site.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.194-198
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• 2012

This paper describes flying inspection apparatus for 22.9kV distribution line. This apparatus is composed of multi-copter(more than 4 propellers), camcorder and remote controller. The existing inspections, such as hot-line inspection job and optical inspection method and distribution Line Checking Robot, have many restrictions. A electric working vehicle and hot-line job license are essential in hot-line inspection job. Besides its high cost, it can't be applied to the electric pole over 18m and road-blocked area. Optical method can't inspect upper side of electric facilities mounted on the electric pole. Robot method can't be applied to the corroded overhead earth wire and nothing of overhead earth wire. To solve the problems, in Korea Electric Power Co., we have applied flying inspection apparatus to the 22.9kV distribution line. The results of trial application show that this paper is practical and effective for the inspection technical method in 22.9kV distribution line

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.736-741
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• 2005

This paper presents electric characteristics analysis and safe configuration for extension power supply between existent 6.6kV ungrounded distribution system and establishment and improvement 22.9kV direct grounding distribution system. For this, we model 6.6kV ungrounded and 22.9kV direct grounding distribution system of urban underground, ground region. and rural electrical, unelectrical region using PSCAD/EMTDC and analyze voltage drop, charging current, ground and short fault through simulation. To analyze electric characteristics of extension power supply, we simulate extension power supply of overhead line of 6.6kV ungrounded system and underground line of 22.9kV direct grounding system of rural electrical region and propose operation condition for safe extension power supply through result of analysis. Characteristics of voltage drop, charging current, ground and short fault appear almost similarly with electrical characteristic of direct power supply. However, because unbalance of phases may cause relay's malfunction of ungrounded system and ground fault current of direct grounding system may demage facilities of ungrounded system, we propose safe system configuration such as impedance grounding system of neutral point.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.182-184
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• 2000

There are several facilities in Kochang distribution test center such as artificial fault generator(AFG), new distribution automation system(NDAS), communication networks (wireless and optic), lumped constant circuit, switches for distribution automation, overhead and underground distribution line. We have been field testing on remote control, data acquisition. remote metering, feeder automation and so on for distribution automation using those equipment.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.945-948
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• 2000

The coupling properties of supermodes guided by grating-assisted directional couplers (GADCs) can be phrased in rigorous modal theory. Such a modal solution for TE modes expressed by simple electrical transmission-line networks is utilized to analyze the power distribution of GADCS with three guiding channels. In particular, the modal transmission-line theory can serve as a template for computational algorithms that systematically evaluate the coupling efficiency that are not readily obtained by other methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2206-2214
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• 2011

LDC(Line Drop Compensation) is widely used in controlling ULTC(Under Load Tap Changer) output voltage at distribution substation. However, LDC may experience some difficulties in voltage control due to renewable energy resources and distributed generations. Therefore, more advanced voltage control algorithm is necessary to deal with these problems. In this paper, a modified voltage control algorithm for ULTC and DG is suggested. ULTC is operated with the voltages measured at various points in distribution system and prevents overvoltage and undervoltage in the distribution feeders. Reactive power controller in DG compensates the voltage drop in each distribution feeders. By these algorithms, the voltage unbalance between feeders and voltage limit violation will be reduced and the voltage profile in each feeder will become more flat.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.250-252
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• 1997

This paper deals with voltage regulation at the power Distribution system interconnected with DSG. Modern distribution substation adopt LDC method as the voltage regulation method to deliver suitable voltages to many customers. However, the operations of DSG interconnected with distribution system, the customers' voltage violate the permissible voltage limits. Therefore, to deliver suitable voltage to many customers at the distribution substation, an advanced voltage regulation method is required. In this paper, the on line realtime MLDC (Multiple Line Drop compensation) method, considered daedband and hysterical tap changing of the ULTC, is proposed. The result from a simulation study shows that the proposed method can be practical applications for the voltage regulation at the distribution system interconnected with DSG and unbalanced load pattern among feeders.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.61-67
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• 2006

The use of the wind energy resource is a rapidly growing area world-wide. The number of installed units is continuously increasing, and therefore, it is important to respect and to deal with the impact of wind power generation system. From the view of an electric grid utility, there is a major problem with the impact of the wind system on the voltage of the electric grid, to which a turbine is connected. In this paper, it is investigated the voltage impact and transient state analysis on distribution line, with which wind power generation system is connected. Connections of wind power system usually occur to voltage drop due to reactive power absorption and sometime result in higher than nominal voltage.