• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.587-593
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• 2021

Since 2017, a total of 29 fire accidents have occurred in energy storage systems (ESSs) as of June 2020. The common mode voltage (CMV) is one of the electrical hazards that is assumed to be a cause of those fire accidents. Several cases of CMV that violate the allowable insulation level of a battery section are being reported in actual ESS operation sites with △-Y winding connections. Thus, this paper evaluates the characteristics of CMV. An ESS site was modeled with an AC grid, PCS, and battery sections using PSCAD/EMTDC software. As a result of a simulation based on the proposed model, it was confirmed that characteristics of CMV vary significantly and are similar to actual measurements, depending on the grounding method of the internal transformer for PCS. The insulation level of the battery section may be severely degraded as the value of CMV exceeds the rated voltage in case of a grounding connection. It was found that the value of CMV dramatically declines when the internal transformer for PCS is operated as non-grounding connection, so it meets the standard insulation level.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1013-1024
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• 2022

In addition to the assessment measure of electric quality levels, load loss are also a factor in hindering the financial profits of electrical sales companies. Therefore, accurate analysis of load losses generated from distributed power networks is very important. The accurate calculation of load losses in the distribution line has been carried out for a long time in many research institutes as well as power utilities around the world. But it is increasingly difficult to calculate the exact amount of loss due to the increase in the congestion of distribution power network due to the linkage of distributed energy resources(DER). In this paper, we develop smart grid big data infrastructure in order to accurately analyze the load loss of the distribution power network due to the connection of DERs. Through the preprocess of data selected from the smart grid big data, we develop a load loss analysis model that eliminated 'veracity' which is one of the characteristics of smart grid big data. Our analysis results can be used for facility investment plans or network operation plans to maintain stable supply reliability and power quality.

• JOURNAL OF ELECTRICAL WORLD
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• s.286
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• pp.64-69
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• 2000

20세기에 있어서의 비약하는 산업계의 주축으로서 철강시장은 급속히 확대되었고 그와 더불어 신기술의 개발과 도입에서도 선도적 역할을 다하여 왔다. 특히 이 4반세기는 반도체기술의 진보와 함께 컴퓨터, 플랜트 컨트롤러, 드라이브 시스템 등 전기제품은 비약적인 진화를 이루어 왔다. 현재는 중국$\cdot$아시아$\cdot$남미를 중심으로 철강제품의 수요가 증가하여 설비투자도 확대되고 있다. 그러나 북미$\cdot$유럽$\cdot$일본에서는 생산능력과 수요와의 사이에 수급공백이 있어 이전과 같은 시장만큼의 신장은 기대할 수 없는 실정이다. 이와 같은 상황하에서 철강유저의 투자목적을 합리화$\cdot$성력화$\cdot$제품품질의 향상에 두고 있어, 미쓰비시전기는 ''경쟁력 있는 제품을 만들기와 총투자코스트의 최소화''를 서포트하는 제철플랜트용 전기제품의 제공을 지향하여, 그림에 표시하는 것과 같은 4개의 어프로치로 이에 대응하고 있다. 고품질화와 자동화에 대하여는 종래의 품질제어를 능가하는 초안정화 시스템의 적용, 프로세스의 이상 검지와 자동복구에 의한 완전 노터치 오퍼레이션의 실현, 인텔리전트 센서에 의한 프로세스의 가시화로 오퍼레이터가 최종판단을 용이하고 정확하게 할 수 있는 환경을 제공한다. 고효율화$\cdot$에너지 사용합리화에 대하여는 고역률 전원을 추구하여 고효율 드라이브장치와 모터를 제공한다. 글로벌 스탠더드화에의 대응으로서는 네트워크의 오픈화에 의한 멀티벤더 환경, 범용 하드웨어에 의한 오픈 HMI(Human Machine Interface)을 제공하고 있다. 플랜트의 신속한 가동과 리모트 메인터넌스 환경을 실현하기 위하여 플랜트 시뮬레이션 시험의 실시로 공장출하 품질의 향상을 도모한다. 또한 연구센터로부터의 원격감시와 트러블해석 서포트를 쉽게 할 수가 있다. 나아가 최근에는 급격한 기세로 신장되어 온 멀티미디어 기술, 인터넷 기술, 인트라넷 기술, 모바일단말, 화상압축기술 등에 의하여 원격집중감시, 현장과 중앙 쌍방향 협조보수작업, 버추얼 리얼리티 응용시스템이 현실화 되고있는 실정이다. 이들 IT(Information Technology)솔류션은 금후의 제철플랜트의 시스템을 크게 바꾸어 나가는 것은 물론 사업 경쟁력 강화의 키 테크놀로지가 될 것이다. 앞으로 미쓰비시전기는 제철플랜트에 대하여 유저니즈를 IT 솔루션으로 전개, 제공해 나가고자 한다.

• Journal of the Korea Convergence Society
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• v.2 no.4
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• pp.21-27
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• 2011

Recently, new distributed power sources such as photovoltaic, wind power, fuel cell systems etc. are energetically interconnected and operated in the distribution feeders, as one of the national projects for alternative energy. When new power sources are considered to be interconnected to distribution systems, bi-directional power flow and interconnection conditions of new power sources may cause several power quality problems like voltage sag, voltage swell, harmonics, since new power sources can change typical characteristics of distribution systems. Under these situations, this paper deals with the analysis the power quality problems at primary and secondary feeders in distribution systems, when new power sources like photovoltaic (PV) systems are interconnected, by using the test devices for PV systems based on the LabVIEW S/W. This paper presents the test device which is consisted with model distribution system and model PV systems. By performing the simulation for power quality operation characteristic based on the test facilities, this paper presents the optimal countermeasures for power quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4171-4176
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• 2012

The conventional block systems for railway signaling currently in operation in Korea have not been electrified or integrated and therefore there have been difficulties in terms of construction and maintenance. Two independent systems have been installed for ABS and LEU of ATP system (for speeded-up lines), although they deal with the same signaling information at the same location in order to control the trains. In these conventional ABS and LEU, a number of duplicate modules are installed in each device including lamp detection units and power supply units and it results increased manufacturing costs and maintenance efforts. This paper deals with the prototype development of integrated electronic block system with CPU-based digital control methods in order to overcome the limitations of the conventional ABS. The suggested system is the integration of the conventional ABS with LEU of ATP and it is also applicable for the non-ATP sections as well.

• Journal of Korean Society of Disaster and Security
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• v.7 no.2
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• pp.1-8
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• 2014

Smart Pole Measurement System was constructed with not only the core sensors of a GNSS receiver, a TRS sensor and a soil moisture sensor but supplementary installation of power supply and radio communication for monitoring steep slope sites. Also a data processing software for displacement extraction and visualization was developed. Smart Pole Measurement sensor is composed of a GNSS antenna at the top of the pole, a TRS sensor and a gyro sensor vertical below right of the antenna and a soil moisture sensor at the bottom of the pole. The sensor combination extracts not only ground combination in real time but transltion, slide, settlement and soil moisture content. This measuring/monitoring system which cosists of data receiving part, data collection/transfer part and data processing part was built to exercise their functions and then test measuring/monitoring was conducted by introducing artificial displacement and the results were analyzed to evaluate field applicability.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.433-439
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• 2015

Recently, Interest in power the quality was increased because of increasing the use of sensitive load equipment into an electrical disturbance such as computer, Electricity, Electronics, Telecommunications and semiconductor device. In addition, To enhance power quality, the instantaneous voltage drop occurred in precision load equipment is a need for proper compensation. In order to solve the problem, The developed dynamic voltage restorer (DVR) using an electric double layer capacitor (EDLC) has been applied. In this paper, We will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. Also, As a emergency luminaires of emergency power supply that we can support more than 10 years of life was confirmed the applicability of hybrid capacitor.

• KDI Journal of Economic Policy
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• v.19 no.4
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• pp.159-215
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• 1997

전기요금수준과 요금체계는 산업의 생산비와 가계의 소비생활패턴에 직접적인 영향을 미쳐, 생산활동 산업구조 소비형태에 변화를 초래한다. 또한 적정요금의 부과는 미래의 전력수요에 부응하는 전원개발의 비용확보와 이를 통한 전력수급 안정에 필수적인 사항이다. 전기요금체계가 경제적으로 효율적인 한계비용방식으로 장기적으로 전환되겠지만 이에는 상당한 시간이 필요하다고 예상되므로, 본 논문에서는 현재 한전이 택하고 있는 평균비용방식에 의거한 용도별 요금체계의 문제점을 지적하고 중단기적 개선방안을 제시한다. 현재 용도별 요금에서의 문제점을 지적하자면, 일반용요금은 평균비용에 비해 과다하게 높은 데 반해 농사용요금은 과다하게 낮다. 또한 일반용에서 계시별 구분을 적용받는 소비자가 너무 적으며 선택요금이 다양하지 못하다는 문제점이 있다. 주택용요금은 평균비용과 상당한 괴리가 있으며, 현재의 7단계분류는 보통 외국의 3단계 분류에 비해 복잡하며 단계별 누진율이 과다하게 높다. 주택용의 기본요금과 전력량요금이 모두 누진적이나 이에 대한 경제적 논거가 약하다. 전기요금의 중단기적 개선의 기본방향은 한계요금체계에의 근접화, 정책적 왜곡의 최소화, 수요관리 요금체계의 강화로 정리될 수 있다. 현재의 전기요금체계는 산업정책 소득정책 정치적 선택 등 정책적 요소를 혼용하고 있는데, 정부의 경제개입이 줄어드는 추세에 맞추어 전기가 필수재라는 요소 이외의 정책적 요소는 사라져야 한다. 또한 전기가 피크기의 수요에 맞추어 용량을 확보해야 하는 특성을 가지고 있으므로 피크기의 수요관리는 설비비용의 절약으로 소비자 모두에게 혜택을 줄 수 있다. 본 논문에서는 위의 기본방향을 기반으로 하여 구체적 개선방안으로 산업용 일반용 교육용의 전압별 통합, 산업용 일반용의 선택요금 및 차등폭 확대, 요금의 비용 근접화, 농사용내의 구분 단일화, 주택용의 체계 단순화, 누진율의 대폭 완화, 하계수요관리 요금의 도입, 계시별 차등요금시간대 단순화를 제안한다. 이러한 개선방안은 현재의 전기요금체계를 경제학적 논리기반에 근접화시키고 좀도 효율화 합리화시킬 수 있을 것이다.

• Journal of IKEEE
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• v.19 no.3
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• pp.295-303
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• 2015

Considering to Energy Storage System (ESS) is a global trend In order to reduce global warming and carbon emissions. South Korea has announced various policies to vitalize the development and uptake of renewable energy. South Korea is planning the cumulative capacity of ESS of two million kW in 2020. According to the government support and development of technology companies, the battery of ESS prices are expected to fall gradually. In this paper, we develop a planning model that take into account the supply expansion of technology of ESS and prices. Based on planning model, we analyze the cost of ESS linked with wind power and the revenue for trading electricity and renewable energy certifications.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.179-186
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• 2007

KTX control systems mutually control OBCS, ATC, MBU, TECA, MDT, ABU, HVAC, TRAE, PID and FDTR, KTX OBCS as master, and controls other sub-control devices as slave, using various serial lines. In order to analyze physical structure of various serial link lines and mutual data transmission structure, serial line analyzer is used in many ways. To use serial line analyzer, prior and professional technics about High Speed Train and experience of using device are necessary. In spite of difficult situation of space and environment where we work for maintenance of High Speed Train, in presenting basic structure about physical connection method aquired by sub-device serial line data collection and about communication data analysis, I hope that this research will be helpful for the person who work for similar area. Also, I hope that this research will help diagnostic work of High Speed Train, which is necessary for test run of independently developed High Speed Train.