• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1854-1856
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• 2004

In this paper, there have been brief review about the important consideration in laboratory planning and designing 4.2MV impulse voltage generator(IVG), which enable to test and evaluate the UHV dielectric performance of power electric apparatus up to 765kV-class. To improve and reinforce the test ability of the IVG and itself against test object being tested by KERI hereafter, wide investigation and an analysis for a solution, especially overshoot compensation method. With the special consideration about those matters in settling down the 4.2MV IVG have been described with the experimental approaching.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.432-437
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• 1998

Power systems have uncertain dynamics due to a variety of effects such as lightning, severe storms and equipment failures. The variation of the effective reactance of a transmission line due to a fault is an example of uncertainty in power system dynamics. Hence, a robust controller to cope with these uncertainties is needed. Recently fuzzy controllers have become quite popular for robust control due to its capability of dealing with unstructured uncertainty. Thus in this paper we design an adaptive fuzzy controller using an input-output linearization approach for the transient stabilization and voltage regulation of a power system under a sudden fault. Simulation results show that satisfactory performance is achieved by the proposed controller.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.5
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• pp.407-414
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• 2001

In this paper, we present a decentralized robust adaptive fuzzy controller for the transient stability and voltage regulation of a multimachine power system under a sudden fault. Power systems have uncertain dynamics due to various effects such a lightning, severe storms and equipment failure in addition to interconnections between generators. Hence a robust controller to deal with these uncertainties in needed. The fuzzy systems are adapted using a Lyapunov-based design and the stability of each closed-loop system is guaranteed. Simulation results show that satisfactory performance is achieved by proposed controller.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.615-617
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• 1999

In this paper, we present a decentralized robust adaptive fuzzy controller for the transient stability and voltage regulation of a multimachine power system under a sudden fault. Power systems have uncertain dynamics due to various effects such as lightning, severe storms and equipment failure in addition to interconnections between generators. Hence a robust controller to deal with these uncertainties is needed. Simulation results show that satisfactory performance is achieved by the proposed controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1103-1108
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• 2010

A grounding electrode has the transient grounding impedance characteristics against lightning surges. So the performance of grounding electrodes should be evaluated as a grounding impedance as well as the ground resistance. The frequency-dependent grounding impedance is varied with the shape and size of grounding electrode and is divided into both inductive and capacitive behaviors. This paper presents a theoretical analysis for the grounding impedance determined by the size of grounding electrode using the distributed parameter circuit model. EMTP and Matlab programs were used in calculating the frequency-dependent grounding impedances of vertical grounding electrodes. It was found that the frequency-dependent grounding characteristics of vertical grounding electrodes are characterized by the distributed parameters which are changed in the dimension of grounding electrodes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.49-49
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• 2010

In this paper, a full scaled gas discharge chamber was designed and fabricated for evaluating the dielectric performance of SF6/N2 mixture gases. And it describes work on AC and lightning impulse dielectric characteristics of SF6/N2 mixture insulation gas from experiments and full scale models.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.347-348
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• 2008

This paper presents the use of Line Surge Arresters on 154kV double circuit lines. The ouatge rate which is highly related to the tower footing resistance is showed during the last a few year. The general methods that have been adopted at lines also are introduced. Lightning performance of lines without and with line surge arrester is studied and compared. The characteristics between air-gap type and gapless type LSA also compared. Line surge arrester installation strategy is presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.92-98
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• 2012

It is made compulsory to install SPD for the purpose of protecting electric and electronic devices when an abnormal voltage such as lightning occurs to power line using power frequency of 60Hz. Recently, the high speed communication technology utilizing power line is receiving attention again as a communication technology for smart grid. The SPD influences the performances of power line communication when using SPD and power line communication system together. In order to improve the performance of power line communication, a proposed scheme for series connection of gas discharge tube to ZnO varistor was presented. This paper measured the impacts of series connection of GDT to SPD using ZnO varistor on the limit voltage of Class III SPD. This paper also presented the DC operating voltage of GDT which satisfies the limit voltage of power line communication system and SPD simultaneously.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.1161-1165
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• 2005

Due to the miniaturization of electrical components and assembles on signal circuits, transient overvoltages caused by switching operation or lightning surges have become more interesting concern to the field of electrical engineering. In this paper, the development of surge protective devices(SPDs) that can protect sensitive signal device on shipboard from overvoltages are described. Two kinds of SPDs are designed and tested by using a combination surge generator which can produce the standard impulse current of 8/20${\mu}s$ 2.1kA according to the IEC 61000-4-5 standard. From the simulation and experimental results, it is confirmed that the proposed SPDs have an enough protection performance with a low insertion loss and a low clamping voltage.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1578-1582
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• 1998

The ground potential rise generated by the switching surge or lightning stroke may be dangerous to personnel and cause damage to electronic control parts. For a first step to the transient performance analysis. high frequency impedances of grounding grids have been calculated and discussed. Grounding grids include 7 square grids from $10m{\times}10m$ to $80m{\times}80m$. The high frequency current was injected into the center and a corner of the grounding grid. The calculation results indicate that the impedance of the grounding grid is significantly influenced by frequency and the point of injection of the current. and the effective radius of a large grounding grid may be represented in $15{\sim}20m$.