• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.265-267
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• 2003

The wavelet transform(WT) has been extensively applied in solving many problems in applied science and engineering following its introduction in early 1980's. The WT analyzes a signal in a changeable frequency range by employing a moving window whereby along time window is used to obtain low frequency information and short time window is used to obtain high frequency information. In this paper, after various fault types in 154 KV transmission system was simulated by using EMTP, and the RMS values by changing Mother wavelet was calculated by applying wavelet transform to the simulated voltage and current signal.

• Advances in Energy Research
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• v.3 no.3
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• pp.133-142
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• 2015

A large wind farm can be simplified by the aggregated wind farm models for load flow, steady and transient stability studies. When a fault (such as a short circuit) happens in a large wind farm, some of wind turbines trip while others do not. This paper is to design a controller to modify the aggregated wind farm model in the case of one or more unit removed or added from the complete model. This is without stopping the simulation process during performing the steady state and transient analysis of the whole system. This controller can modulate the status of the wind turbines in the aggregated model in a given farm according to any change in this farm. By this controller, we save effort and time to change the status of wind turbines in the aggregated model. The proposed wind farm is composed of some smaller farms of permanent magnet synchronous generators (PMSGs) and others of squirrel cage induction generators (SCIGs).

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.731-735
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• 2006

The Rolling Stock pursues more safe, speedy and accurate operation on the increment of the passenger and the short headway. Signalling system is providing an assurance on safety and reliability of the system, which is based on fail-safe concept. Therefore we are willing to study up on MMI device for new onboard ATP/ATO equipment which is used for driver to recognize train status and fault more quickly and to solve any problem more rapidly, which can maximize the stability and reliability of the system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.538-544
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• 1999

One of the most important requirements for the development of computerized relay setting system is its openness to abbommodate the various changes like new panel additions. This paper describes the relay settein-coordination system(PROSET2000), which has an open system architecture and adopts the dbject oriented programming paradigm. Its main features include the intelligent fault type identification, automatic running of the short circuit analysis, ren-time rulebase modification, automatic documentation, ect.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.3
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• pp.140-145
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• 2001

The instantaneous voltage drop is occurred when the fault is happened on the nearby feeders. The instantaneous voltage drop is continued during relatively short period. But, the effect of it can be very severe to some sensitive devices. That is, it can be the reason of restart or malfunction of some devices. And these phenomenons can cause the enormous economical damage and shorten the lifetime of the devices. In this paper, the device which can compensate the instantaneous voltage drop, is studied. Through the computer simulation using PSCAD/EMTDC, the validity of the control algorithm using peak detection method is verified. And the Dynamic Voltage Restorer(DVR) prototype is designed and constructed. Through the experiment, the function and performance of the DVR prototype is verified.

• Journal of Power Electronics
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• v.2 no.2
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• pp.88-94
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• 2002

The demand for protection of power electronic application has during the last couple of vears increased regarding the high-power IGBT modules. Even with an active protection, a high power IGBT still has a risk of exhibiting a violent rupture in the case of a fault if IGBT Fuses do not protect it. By introducing fuses into the circuit this will increase the circuit inductance and slight inductance over-voltage during the turn-off of the diode and the IGBT. It is therefore vital when using fuses that the added inductance is kept at a minimum. This paper discuss three issues regarding the IGBT Fuse protection of adding inductance of existing High-speed and new Typower Fuse protection. First, the problem of adding inductance of exiting High-speed and new Typower Fuse DC-link circuit is treated, second a short discussion of protection of the IGBT module is done, and finally, the impect of the high frwquency loading on the currying capability of the fuses is presented.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.712-714
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• 2001

매쉬 구조를 갖는 다중 프로세서에서의 오류를 허용하는 라우팅 기법은 구현에 있어 간결함을 제공하는 환경으로, 다수의 오류를 허용하기 위해 직사각형 모양의 오류 블록으로 구성하여 라우팅을 수행한다. 이 경우, 블록 내부의 정상적인 노드 역시 오류 노드로 간주되어 전체 노드의 사용율을 저하시키는데, 오류 블록을 몇 개의 확장된 매쉬로 나누고 DAG(Directed Acyclic Graph)에 적용하여 메시지 전송의 최단 거리를 구하는 RIFP(Routing for Irregular Faulty Pattern)기법으로 이를 해결하였다. 그러나, 이 기법은 노드간에 주고받는 메시지가 거치는 hop의 수가 오히려 증가되는 문제가 발생하게 된다. 본 논문에서는 증가되는 hop의 수를 억제하기 위해 목적 노드와 이웃 노드들로부터 오류블록 경계 부분까지 직선 경로를 찾는 SCP(Short-Cut Path)를 적용한 RIFP를 제안한다.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.229-231
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• 1998

One of the most important requirements for the development of computerized relay setting system is its openness to accommodate the various changes like new panel additions. This paper describes the relay setting system(PROSET2000), which has an open system architecture and adopts the object oriented programming paradigm. Its main features include the intelligent fault type identification, automatic running of the short circuit analysis, run-time rulebase modification, automatic documentation, etc.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.1
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• pp.42-48
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• 2019

Since the underwater telephone was sold in a short time, there are few repair equipments. And equipment is difficult to locate fault. Equipment with transducers must be inspected underwater, and a relative naval vessels is required to perform an operational check. So we developed a tester device to test the transmission card through the spectrum and transmission power, and to develop a device that can conduct operational tests on land. Therefore, the development of the tester reduces the incidence of naval vessels and contributes to the development of domestic underwater communication test equipment.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.9-11
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• 2018

This paper studies on the development of an electric fire prevention system with the detection and alarm in case of parallel arc fault occurrence in low voltage distribution lines. The proposed detector has the characteristics of high speed operation responsibility and superior system reliability from composition using a large number of semiconductor devices. The line voltage is always feedback, and when an arc or a spark occurs, these are detected by the microcomputer. In addition, we design and develop algorithms using high speed and high precision microcomputer. A new conceptual control technique is adopted that RCD cuts-off by forming a forced short circuit between the phase voltage and ground in the event of an electrical accident. Some experimental tests of the proposed system also confirm practicality and the validity of the analytical results.