• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.17-19
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• 2005

This paper illustrates the case studies of reliability evaluation for interconnecting power systems in the north east Asia by using the tie line constrained equivalent assisting generator model(TEAG), which has been already developed in the second project year. A reliability evaluation program, it is named, NEAREL. based on the TEAS model was made. The reliability evaluation results for the seven interconnection scenarios of the actual power systems of six countries in the north east Asia are introduced and compared. The reasonable capacity of the tie line for three countries interconnection senario is suggested from sensitivity analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.47-53
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• 2015

The study concerning about the grid connection of the large-capacity energy storage system(ESS) is increasing. However, the transient study such as lightning or switching surge necessarily occurred at power system with ESS has been hardly performed. Therefore, this paper performs the analysis of lightning surge in distribution system with ESS using electromagnetic transient program(EMTP). The battery model in Matlab/Simulink is modeled by EMTP, which is the specialized software for power system transient study. Also, the bi-directional power electronics for interconnection of the battery and distribution system are modeled by EMTP. When the lightning is occurred at interconnection point of ESS, this paper simulates the existence of ESS and operation conditions of ESS and analyzes the surge in distribution system and ESS according to the various conditions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.23-30
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• 2000

Cogeneration systems are seen as a significant innovation for dispersed energy generation since they are both environmentally friendly and has comparatively high degrees of efficiency. It is especially suited for the decentralized provision of electricity and heat. However, it causes operational problems such as voltage regulation, voltage variation, protection and safety. Especially, it is expected that the interconnection/disconnection operation of cogeneration system has an effect on distribution voltage regulation and variation. Recently, with the increased use of customer-owned computers and other sensitive electronic equipment, electric power quality has become an important concerns. Therefore, the voltage quality problems with cogeneration system should be investigated because the voltage quality is an important part of electrical power quality. In this paper, the momentary voltage dips associated with the interconnection/disconnection operation of cogeneration system are analyzed, including restraint solutions at the customer level. In addition, the unit capacity of cogeneration systems per feeder are evaluated from the view point of momentary voltage variations. The results of this paper are useful analysis data for interconnection standards/guidelines of cogeneration systems and dispersed generation (DG)

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1101-1104
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• 2005

The overall objectives for Korean railway system of the future are speedup, capacity management, increase safety, environmental protection. and enhancement efficiency. To achieve these, interconnection within the railway system must be optimised and designed on a customer-friendly basis. This principles applies to both passenger and freight traffic. for which cost-effective and time-efficient facilities must be provided. As the result. Korean railway network modernization is based on seeking out optimum conditions for improving railway business.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.666-669
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• 1993

The space charge fields, including intermode apace charge fields in photorefractive material with two impurities are obtained for the small light intensity at large modulation depth, and their implication of high-capacity volume holographic interconnection are presented. In the following data regions the effect of intermode space charge fields are suppresed and the criteria for optimal implementation of volume holographic interconnections are satisfied.

• The Journal of Information Technology and Database
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• v.8 no.2
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• pp.41-60
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• 2001

Despite the growth in Internet users, demand for multi-medial, large data files and resulting explosive growth in data traffic, there has been lack of investment in Middle-Mile, interconnection of various networks, resulting in bottleneck effect, which is acerbating. One strategy to overcome such network bottleneck is Content Delivery Network (CDN). CDN does not achieve efficient delivery of large file data through physical improvement/increase in network capacity, but by delivering large file contents, the cause of bottlenecks, from distributed servers. Since it is impracticable to physically improve networks capacity to accommodate the growth in internet traffic, CON, by strong CPs contents at cache servers deployed at major ISPs networks, is able to deliver requested contents to the requesting Web clients without the loss of data and long latency.

• Proceedings of the KIEE Conference
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• summer
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• pp.409-411
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• 2004

The need for Fault Current Limiters (FCL) is associated with the continuous growth and interconnection of modem power systems and increase in dispersed generation facilities, which result in progressive increase in the short circuit capacity far beyond their original design capacity. Fault Current Limiters (FCL) clips the fault currents and reduces the electromechanical stresses on the network and the need to handle excessive fault currents. In addition, the reduction of the fault duration Provided by the limiter should increase the power transmission capability and improve the dynamic stability. This paper proposes the model of resistive type superconducting fault current limiter using EMTDC(Electromagnetic transients for DC analysis program). In order to verify the effectiveness of the SFCL, in this paper, the analysis of fault current in a transmission system through the EMTDC based simulation by using the modeled component of a resistive type SFCL is peformed and the detailed results are given.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1069-1070
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• 2008

At the coupling area linking high speed line and conventional line, according to distance between trains due to speed limit of conventional line, the power load of substation supplying to this conventional line increase. At the coupling area between Kimcheon SS and Kyoungsan SS, train operation have problems caused by instantaneous voltage drop. So, this paper propose evaluation method of maximum load capacity at current normal feeding condition.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1916-1922
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• 2009

Introducing distributed generators(DGs) to utility distribution system can cause malfunction of relay on the grid when ground faults or severe load unbalances are occurred on the system. Because DGs interconnected to the grid can contribute fault currents and make bidirectional power flows on the system, fault currents from DGs can cause an interference of relay operation. A directional over current relay(DOCR) can determine the direction of power flow whether a fault occurs at the source side or load side through detecting the phases of voltage and current simultaneously. However, it is identified in this paper that the contributed fault current(Ifdg) from the ground source when was occurred to contribute single-line-to-ground(SLG) fault current, has various phases according to the distances from the ground source. It means that the directionality of Ifdg may not be determined by simply detecting the phases of voltage and current in some fault conditions. The magnitude of Ifdg can be estimated approximately as high as 3 times of a phase current and its maximum is up to 2,000 A depending on the capacity of generation facilities. In order to prevent malfunction of relay and damage of DG facilities from the contribution of ground fault currents, Ifdg should be limited within a proper range. Installation of neutral ground reactor (NGR) at a primary neutral of interconnection transformer was suggested in the paper. Capacity of the proposed NGR can be adjusted easily by controlling taps of the NGR. An algorithm for unidirectional relay was also proposed to prevent the malfunction of relay due to the fault current, Ifdg. By the algorithm, it is possible to determine the directionality of fault from measuring only the magnitude of fault current. It also implies that the directionality of fault can be detected by unidirectional relay without replacement of relay with the bidirectional relay.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.138-145
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• 2017

With the increasing use of smart electronic devices, the size of the related I/O interface market is increasing rapidly. Demand is also growing for the continuous increase of data and video signals-such as faster data processing speed and data storage capacity-in the smart electronic device input/output interface market. Currently, the POF hybrid cable used in the smart electronic device input / output interface market cannot transmit over a long distance because the optical loss is too large, and the GOF hybrid cable is both vulnerable to bending and other sudden outside changes, and expensive. Therefore, in this study, the design and fabrication of a GOF hybrid cable and fiber guide were carried out in order to develop a cable which can easily withstand external impact, has low optical losses, and meets the demand for continuous data and video signal increase in the smart electronic device input / output interface market.