• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.2
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• pp.174-181
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• 2012

Energy storage system connected to the grid has two functions such as the surplus power of a grid is stored in batteries or the energy stored in batteries will supply to the grid when the grid needs. The battery energy storage system consist of power condition system (PCS) for power supply and battery conditioning system (BCS). Lithium-ion batteries are mainly used. In this paper, the battery energy storage system connected to the grid described. The configuration of the 2MVA class power control system using water cooling and battery system are presented. And control method for the system and the output filter design method are proposed. Experimental verification of the proposed system is provided with 2MVA PCS and 500kWh BCS.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.23-26
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• 2003

This paper presents conceptual design and 3-D electromagnetic analysis of IMVA transformer with BSCCO-2223 High Tc Superconducting (HTS) tapes. The rated voltages of each sides of the transformer are 22.9 kV and 6.6 kV, and double pancake windings were adopted. High voltage and Low voltage sides were composed of several double pancake windings. Four HTS tapes were wound in parallel for the windings of low voltage side and were transposed in order to distribute the currents equally in each conductor The transformer core was designed as a shell type core made of laminated silicon steel plates and the core is separated with the windings by a cryostat with Fiberglass Reinforced Plastics(FRP). A sub-cooling system using L$N_2$ were designed to maintain the coolant temperature 65K. Finally perpendicular components of magnetic field applied to tapes were calculated 0.247 in the rated operation using 3-D analysis. A real 1MVA HTS transformer will be manufactured in near future based on the design parameters presented in this paper.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.282-283
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• 2017

본 논문은 (주)효성 중공업연구소에서 국책과제를 통해 자체 개발한 MMC(Modular Multi-level Converter) type ${\pm}12kV$ 25MVA HVDC 시스템에 대하여 실증단지 구축 및 commissioning test에 대한 소개를 한다. 제주에 구축된 HVDC 실증단지는 국내 유일의 MMC type 전압형 HVDC 시스템이며 11-레벨의 AC 출력 전압을 형성하는 2개의 컨버터가 Back-to-Back 형태로 구성되어 있다. 각 컨버터의 AC 출력단은 각각 계통과 풍력발전단지에 연계되어 풍력발전단지에서 생산된 전력을 계통으로 전송하는 역할을 한다. 주요 AC/DC Yard 기기들로는 AC 고조파 필터, 밸브리액터, DC 리액터, 변압기, CGIS등이 있다. HVDC 의 commissioning test를 위해 IEEE, IEC, Cigre TB 등의 문서들을 종합 분석하여 당사의 시스템에 알맞은 시험절차서와 검증항목을 준비하였다. 본 논문에서는 당사에서 준비한 시험절차서 및 검증항목에 대하여 소개하고자 한다.

• Progress in Superconductivity and Cryogenics
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• v.9 no.1
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• pp.67-71
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• 2007

HTS transformers which have been developed until now had only fundamental structures. Among the auxiliary functions of conventional transformers, voltage regulating is the most important one. For the voltage regulation, conventional transformers are equipped with on load tap changers (OLTCS). In this paper, we describe the possibility of the HTS transformer with OLTC. For the case study, we designed a single phase 33 MVA HTS transformer with OLTC. It is one of three individual HTS transformers which composes a 3 phase, 100 MVA transformer. It is expected to substitute for a 3 phase, 60 MVA conventional transformer in Korea. The parameters of an HTS transformer are varied due to the gap length between primary and secondary windings. The length was decided for the transformer to have the impedance of 12 %. Its size was limited to the one of the conventional transformer. The characteristics of the HTS transformer were analyzed in both case of having OLTC and not.

• Journal of Digital Convergence
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• v.21 no.3
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• pp.41-48
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• 2023

As the 4th Industrial Revolution accelerates, the future of the economy faces new uncertainties, particularly around digital transformation. This shift is crucial in today's ICT-centric world. Korea, a significant contributor to global Manufacturing Value Added (MVA), is poised to expand its share. This paper examines Korea's digital transformation and its global economic competitiveness. By referencing world-renowned analyses, it compares Korea's competitive stance. As industries and economies are on the verge of a technological upheaval, understanding and preparing for these changes is vital for maximizing benefits. This paper also delves into the opportunities and policy challenges presented by digitization in the 4th Industrial Revolution era.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1145-1151
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• 2010

The objective of this work was to analyze the relationship between ovine major histocompatibility complex (MHC) DRB1 gene polymorphism and genetic resistance to hydatidosis in Kazakh sheep. The Ovar (ovine MHC) class II DRB1 second exon was amplified by polymerase chain reaction (PCR) from DNA samples of 702 Kazakh sheep, including 302 sheep with hydatidosis and 400 health controls. PCR products were characterized by the restriction fragment length polymorphism (RFLP) technique using five restriction enzymes, i.e., MvaI, HaeIII, SacI, SacII and Hin1I, yielding 14 alleles and 28 genotypes. Comparing the frequency of genotypes in hydatidosis sheep with the control group, it was found that the genotype frequencies of MvaIbc, Hin1Iab, SacIIab, HaeIIIde, HaeIIIdf and HaeIIIdd in control sheep were significantly (p<0.01) higher than in hydatidosis sheep, indicating that a significant correlation existed between these genotypes and resistance to hydatidosis. Genotype frequencies of MvaIbb, SacIIaa, Hin1Ibb and HaeIIIef in sheep with hydatidosis were extremely significantly (p<0.01) higher than in the control group, and the genotype frequency of HaeIIIab was significantly higher (p<0.05), indicating that a marked correlation existed between these genotypes and susceptibility to hydatidosis. By way of analyzing haplotype with these resistant genotypes, the hydatidosis resistant haplotype MvaIbc-SacIIab-Hin1Iab of Kazakh sheep was screened out, and then verified through artificial hydatid infection in sheep. The results indicated that the infection rate of sheep with the resistant haplotype of hydatidosis was significantly lower (p<0.01) than without this resistant haplotype. It showed that the genic haplotype MvaIbc-SacIIab-Hin1Iab of Ovar-DRB1 exon 2 was the resistant haplotype of hydatidosis in Kazakh sheep.

• Korean Journal of Psychosomatic Medicine
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• v.7 no.2
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• pp.174-183
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• 1999

Objective : This study was designed to evaluate the incidence and characteristics of posttraumatic stress disorder(PTSD) after motor vehicle accidents(MVA) in 44 consecutive MVA victims referred to psychiatry for the diagnosis, treatment and psychiatric assessment. Method : The diagnosis of posttraumatic stress disorder was made on the basis of DSM-IV criteria, and posttraumatic stress symptoms were assessed by the Clinician-Administered PTSD Scale(CAPS). Correlation between the extent of physical injury and the severity of PTSD symptoms using the Abbreviated Injury Scale(AIS) was analyzed and the frequency of psychiatric comorbidity of PTSD was invested. Result : Twenty-two(45.5%) MVA victims met DSM-IV criteria for PTSD, while thirteen(29.5%) showed a subsyndromal form of it. AIS scores significantly related with the development of posttraumatic stress symptoms(r=0.565, p=0.0001). PTSD group showed high percentages of each of the 17 symptoms(criterion B, C, D), while subsyndromal PTSD group showed relatively high percentages of criterion Band D. The most frequent symptom was 'distressing dreams' of criterion B in both group. A high percentages(56%) of the MVA-PTSD group also met the criteria for current major depression. Conclusions : These findings suggest that there is apparently a high likelihood of developing all or part of the PTSD syndrome after motor vehicle accidents. So it does appear that for those MVA victims who seek medical attention and eventually need psychiatric referral, diagnostic possibility of PTSD should be taken into account in treatment planning and early intervention.

• Superconductivity and Cryogenics
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• v.9 no.2
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• pp.6-9
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• 2007

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.127-128
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• 2013

본 논문은 POSCO ICT가 개발한 2MVA/500kWh급 BESS(Battery Energy Storage System)의 가파도 마이크로그리드 적용사례와 실증결과에 대해 기술하였다. 이를 위해 가파도 마이크로그리드 구성과 BESS 역할을 설명하였고, 적용된 기술을 소개하였다. 또한 시험항목과 의의를 서술하고, 시험결과를 통해 계통망의 전력품질 및 BESS 제어성능을 검증하였다.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1933-1935
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• 1997

The availability of high power IGBT has led to development of controllable reactive power and harmonics compensation source for use in power transmission system. The paper describes the fundmental operating principles and several application examples. The control technique of reactive power and harmonics compensation for Distribution STATCON is presented, and the computer simulation results are shown to show the effectiveness of tile proposed control technique.