• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1347-1353
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• 2011

While most of the existing protection schemes have been designed with local information around individual components, these local schemes are not considered capable of protecting the modern electric power gird with growing complexity. Recent blackouts in North America and Europe have renewed the emphasis on coordinated protection and control actions to avoid systemwide blackouts, utilizing all of the available grid information. Thus, this paper proposes a new methodology, Agent-based Colored Petri Net (ACPN) modeling for systematically representing, modeling and analyzing information flows and interactions among the entities of the electric power grid. The paper demonstrates its efficacy and accuracy by investigating an ACPN model of a wide area protection system for a typical power grid. The proposed modeling and analysis schemes may further provide a framework to help assure reliability and interoperability of diverse smart grid components.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1472-1473
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• 2006

During normal machine operation, partial discharge(PD) measurements were peformed with turbine generator analyzer(TGA) in two high voltage motors(rated 6.6 kV). These high voltage motors were installed with 80 pF capacitive couplers at the terminal box. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude (Qm). The trend analyses of NQN and $Q_m$ value are available for monitoring of the insulation condition in stator windings of high voltage motors.

• 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.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.518-521
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• 1993

AS THE POWER SYSTEM BECOMES LARGER AND MORE COMPLICATED, THE NUMBER OF UNEXPLAINABLE FAULTS IS INCREASING. IN ORDER TO EXPLAIN THESE FAULTS, NUMEROUS AND VARIOUS DATA ARE NEEDED. BUT THESE DATA ARE NOT READILY AVAILABLE FROM THE FIELD TEST, SO SHOULD BE OBTAINED FROM THE SIMULATOR WHICH CAN SIMULATE THE POWER SYSTEM EXACTLY AND EASILY. IN THIS PAPER, A DIGITAL SIMULATOR WHICH IS APPROPRIATE FOR THIS PURPOSE IS DEVELOPED. THIS SIMULATOR IS DIVIDED INTO THREE PARTS : DIGITAL SIMULATION PART, D/A CONVERSION AND CONTROL PART AND AMPLIFIER PART. AND, THE FUNCTION OF THE SIMULATOR AND THE FUTURE RESEARCH AREA ARE DISCUSSED.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.817-819
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• 1996

This paper presents an algorithm for calculation of harmonic distribution in distribution systems. In distribution systems, most state variables are not given explicitly. To calculate the harmonic distribution in distribution systems, state estimation is necessary. In this paper, power usage and harmonic current injection is estimated for each node from practically available data. The estimating procedure is illustrated by examples.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.465-466
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• 2007

Available transfer capability(ATC) quantifies the viable increase in real power transfer from one point to another in a power system. ATC calculation has predominantly focussed on steady-state viability. In many power systems, point-to-point transfer is not restricted by steady-state limits, but by undesirable dynamic behavior following large disturbance. In this paper, an energy function method for transient stability ATC computation is proposed, which utilizes a between the potential energy and energy function.

• Nuclear Engineering and Technology
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• v.28 no.3
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• pp.339-348
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• 1996

Plant monitoring algorithm developments seem to be saturated which means that display system to show the results from the algorithm should be the well-defined and interactive tools for operator's diagnosing, controlling, restoring the abnormal plant situations. On the other hand, very little generalized display design concepts and evaluations are available. Events that are unfamiliar to operators and that has not been anticipated by designers may cause great threats to the nuclear power plant system safety operation. The abstraction hierarchy, considered most popular display design methodology but not generalized for nuclear power plant design space, has ken proposed as a representation frame work that can be adopted to design interfaces and supports operators in diagnosing overlooked events that should have been considered to operate plant safely. However most practical plant display systems do not fully stick to this design concept but partially rely on their philosophy from design experiences. Abstraction hierarchy display design concept will be do scribed and the trend of Advanced Control Room(ACR) CRT design will also be presented with the conventional display for the several type of plants. Consequently this complementary material should be of interest to designer and regulators concerned with nuclear power plant.

• Tribology and Lubricants
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• v.20 no.3
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• pp.157-162
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• 2004

The cam curve of a balance type vane pump consists usually of circular arcs and Archimedes' spirals. However, if they are connected directly together, the curve must have a few discontinuous points of the gradients and the motion of the vanes is no longer smooth. Designing data for an oil hydraulic vane pump used in power steering system were obtained by the acquisition of optimum cam profile data which can be available to reduce noises and vibrations through the minimization of cavitation with the improvement of suctional performance. The performance test is carried on the trial manufactures by measuring the volumetric and the mechanical efficiency. And from that result, maintaining the same characteristic as the conventional one in the relief pressure and noise level, the experimental pump discharges 0.7 $\ell$/min and shows nearly 3.5% enhancement in the total efficiency more than the conventional one.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1020-1025
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• 2001

Vertical canned pumps are usually applied in the power plant to transport fluids that the available suction pressure is low at the condensate system and the circulating-water system. The top of the motor driver is 5.5m above the base and the barrel and drop column extend even further below the ground. While this size and configuration may produce an efficient pumping system, it also introduces several dynamic problems which must be considered in order to obtain a reliable operation. The main problem is that the vibrational mode of the long flexible cantilever structure above the ground exist near the operational characteristics of the condensate debris system. This system's trouble has been showed at 2,086 hp condensate water loading pumps in a nuclear power plant.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.103-106
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• 2005

This paper reviews the dynamic load phenomenon referred to as 'silo quaking', caused shock vibration and loud noise, during gravity discharge in coal silos. Quaking in tall silo is examined using experimental data obtained from a Coal Power Plant and several experimental and numerical investigations available in the published literature. In the experiment, the acceleration was measured at various height on the silo column and floor and by doing so, not only could the variation of the amplitude of the quaking be observed, but also the propagation of waves could clearly be seen. Through an overview of recent research on this subject, it is shown that the current silo quaking is produced by slip-stick friction between the internal wall of silo and the granular material, i.e. coal.