• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1247-1249
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• 2003

Despite many advantages, d-q theory was available only for three phase system. But recently, some papers proposed the application methods of d-a theory or similar theories for single phase systems. This paper presents the control method of the utility-connected single-phase inverter using d-q theory. The suggested method gives single-phase system instantaneous controllability and also makes the realization of APF(Active Power Filter) without DFT operation and PFC(Power Factor Controller) possible. This paper deals with utility-connected single phase inverter with PFC function. The controller was verified by simulation tool.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.457-461
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• 1996

An optimum design methodology for the power MOSFET's with a predetermined mask is proposed and verified by comparing with the results of MEDICI simulation and the data of commercially available devices. Optimization is completed by determining a doping concentration and a thickness of the epitaxial layer which satisfy a specific voltage and current rating requirements as well as a minimum on-resistance for the mask set. The commercial HEX-1 mask set with a die area of $40.4{\times}10^{-3}\;cm^2$ and a T0-220 package has the on-resistance of $1.5{\Omega}$ at 200 V/2.5 A rating while the M-1 mask from this study exhibits $0.6{\Omega}$ on-resistance at 200 V/6 A. The 60 % reduction in the on-resistance and 58 % enhancement in the current rating have been obtained by the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1125-1140
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• 2018

This paper analyzes robotic technology developed for live-line electricity distribution and its applicability to domestic environment. In doing so, available robotic systems developed for the live-line work are thoroughly investigated and compared in terms of from robotic functionality to economic feasibility. To assess the technology readiness for domestic live-line robot, the rubber gloves based direct live-line engineering methods have been also analyzed and mapped into robotic technology requisites. The results are expected as a fundamental data to help with solving the safety and economics issues when considering development and introduction of compact live-line robot for complex domestic electricity distribution environment.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2008-2009
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• 2007

The paper considers the relation between on-line monitoring and diagnostics on the one hand and high-voltage (HV) withstand and partial discharge (PD) on-site testing on the other. HV testing supplies the basic data (fingerprints) for diagnostics. In case of warnings by on-line diagnostic systems, off-line withstand and PD testing delivers the best possible information about defects and enables the classification of the risk. Because alternating voltage (AC) is the most important test voltage, the AC generation on site is considered. Frequency tuned resonant (ACRF) test systems are best adapted to on-site conditions. They can be simply combined with PD measuring equipment. The available ACRF test systems and their application to electric power equipment -from cable systems to power transformers - is introduced.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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• pp.207-213
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• 2001

Welding variables and condition in gas metal arc welding (GMAW) effect on the weld quality and productivity, extensive research efforts have been made to analyze the welding variables and conditions. In this study dynamic behavior of GMAW system is investigated using the chararcteristic equations of the power supply. wire and welding arc. Characteristic equation of wire is modified to include the effect of droplets attached at the electrode tip. The dynamic characteristics of arc length, current, voltage with respect to the step, ramp inputs of CTWD was simulated. From results of simulation, some predictions about dynamic characteristics of GMAW and welding process are available. The proposed simulator and results appear to be utilized to determine the proper welding conditions, to be improved by considering power supply dynamic characteristics.

• Proceedings of the KIEE Conference
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• summer
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• pp.286-288
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• 2004

The design of a measurement system to perform Harmonic State Estimation (HSE) is a very complex problem. In particular, the number of harmonic instruments available is always limited. Therefore, a systematic procedure is needed to design the optimal placement of measurement points. This paper presents a new HSE algorithm which is based on an optimal placement of measurement points using Genetic Algorithms (GAs). This HSE has been applied to the Simulation Test Power System for the validation of the new HSE algorithm. The study results have indicated an economical and effective method for optimal placement of measurement points using Genetic Algorithms (GAs) in the Harmonic State Estimation (HSE).

• Nuclear Engineering and Technology
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• v.15 no.2
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• pp.135-141
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• 1983

Computational accuracy of the modified Borresen's coarse-mesh diffusion theory scheme is investigated with the steady-state solutions of the two- and three-dimensional LRA-BWR bench-mark problem. By comparing the numerical results available for the critical eigenvalue and power distribution of the LRA-BWR, it is shown that the modified scheme is capable of predicting the power distribution of the multi-dimensional BWR problem with an improved accuracy.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.931-942
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• 2019

Radioactive materials are released from the molten core into the containment at the time of a severe accident in a nuclear power plant (NPP). Filtered containment venting system is a popular and effective safety measure installed to obstruct the uncontrolled escape of radioactive materials due to the over pressurization of the containment. Different designs of filtered containment venting system (FCVS) are available today, each being the result of extensive research and development varying in one way or the other. This paper gives an elaborate description of the different types of FCVS currently being used, the current usage status in over 17 countries and the legislations regarding it. The recent researches being carried out in this field has also been discussed in detail. This present paper focuses on the critical review of existing FCVS, reports the challenges faced by it and highlights the potential developments to overcome the difficulties.

• Communications for Statistical Applications and Methods
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• v.26 no.2
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• pp.191-203
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• 2019

The problem of examining how well an assumed distribution fits the data of a sample is of significant and must be examined prior to any inferential process. The observed failure time data of items are often not wholly available in reliability and life-testing studies. Lowering the expense and period associated with tests is important in statistical tests with censored data. Goodness-of-fit tests for perfect data can no longer be used when the observed failure time data are progressive Type II censored (PC) data. Therefore, we propose goodness-of-fit test statistics and a graphical method based on generalized Lorenz curve for PC data from a location-scale distribution. The power of the proposed tests is then assessed through Monte Carlo simulations. Finally, we analyzed two real data set for illustrative purposes.

• Journal of Power Electronics
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• v.19 no.2
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• pp.413-430
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• 2019

This paper presents an optimum hybrid SVPWM technique for three-level voltage source inverters (VSIs). The proposed hybrid SVPWM technique aims to minimize total harmonic distortion (THD). A new parameter is introduced to incorporate the heterogeneous nature of switching sequences of SVPWM technique. The proposed hybrid SVPWM technique is implemented on a low-cost PIC microcontroller (PIC18F452) and verified experimentally with a 2 KVA three-phase three-level insulated gate bipolar transistor-based VSI. Optimum switching sequence results in the three-level inverter configuration are demonstrated. The proposed hybrid SVPWM technique improves the THD performance by 17.3% compared with the best available three-level SVPWM technique.