• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.563-564
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• 2015

Recently, distributed generation using renewable energy resources have increased due to the limitation of conventional energy. To utilize these energy source effectively, a method of applying the energy storage system(ESS) in distribution system has been considered. In this paper, we simulated the one line-to-ground fault in power system with ESS. Based on these simulations, we analyzed the effect on Over Current Relay(OCR) operation. As a result, ESS operation modes result fault current fluctuation. Thus, OCR need to reset the pick up current. This paper analyze effect of ESS in distribution system according to OCR setting by using ElectroMagnetic Transient Program(EMTP).

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.506-508
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• 1995

The relay protection engineers are sometimes faced with the difficulties in full protection of high-inertia drive motors during acceleration period. The problem results from lower permitted locked rotor time of the motor compared with motor starting time. Even though the various types of protection relay and other device (Speed switch, Distance relay) are used, the full protections against abnormal starting conditions may not be available. So, the development of a new speed-biased overcurrent relay is suggested in this paper. This paper also presents that speed-biased overcurrent relay can fully protect the high-inertia motor during abnormal starting condition by computer simulation.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.336-337
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• 2011

접지시스템 구축의 근본 목적은 인체의 안전(Safety)과 설비의 안정(Stability)을 목적으로 하며, 보호목적에 따라 전력설비용 접지와 약전용 접지로 크게 나눌 수 있다. 전력설비용접지(Frame Earth)는 감전이나 설비의 피해를 방지하기 위한 것으로서 주로 보안용접지에 속하며 평상시에는 접지선에 전류가 흐르지 않는 것이 일반적이다. 이에 반하여 약전용접지(Signal Earth)는 전자통신 회로의 안정된 동작을 확보하기 위한 것으로 평상시에도 전류가 흐르는 것이 일반적이다. 이와 같이 접지시스템은 인축의 안전과 설비의 안정적 가동확보를 위해 대단히 중요한 설비이며, 특히 전력설비용 접지의 목적은 대지면의 국부적 전위상승에 따른 인체의 감전사고방지와 1선지락사고시 전위상승억제 및 보호계전기의 확실한 동작을 도모하기 위하여 실시한다. 본 연구에서는 2011. 10월 준공예정인 시화조력발전소의 전력설비용 접지시스템을 대상으로 IEEE에서 제시하는 목표접지저항값 유지여부를 평가하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.5
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• pp.728-733
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• 2010

The conventional electro-mechanical circuit break and relay are widely used in large-sized DC power system. However, recently due to high reliability, remote controllability and small power dissipation of a RSSPC(Remote Solid State Power Controller), high-friendly DC power systems have increasingly adopted the RSSPC as a essential element. In this paper, we have conducted a mathematical modeling to analyze the performance of the proposed RSSPC system with the optimal signal range for $I^2t$. Based on the calculation, the RSSPC system has been implemented by DSP.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.741-742
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• 2011

In this paper, an over-current relay algorithm module for a network-based protective relay simulator is proposed. The proposed protective simulator is based on the client-sever paradigm. The module composed of a server and user interface provides a network-based simulation environment.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2193_2194
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• 2009

A digital over current relay(OCR) is realized by using TMS320C32 microprocessor. Fourier Transform is used to obtain the phasor of a current signal and a 2nd low pass filter is adopted to prevent aliasing error. H/W test shows almost same results with those of the S/W test. It could be possible that confirm simularity between H/W and S/W test in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1065-1070
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• 2009

This paper presents the new technique of modeling using Dynamic Link Library(DLL) in ElectroMagnetic Transients Program - Restructured Version(EMTP-RV) in which we have simplified the procedures of OverCurrent Relay(OCR) modeling. The DLL function is designed to allow EMTP-RV users to develop advanced program model modules and interface them directly and intimately with the EMTP-RV engine. The modeled OCR is verified by simulating the various fault cases in the distribution system. Also, the performance for the modeling of OCR using DLL is compared with that of the method using the control components of EMTP-RV and using EMTP/MODELS. The results show the validity of modeled OCR and the effectiveness of the method using DLL function.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.677-682
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• 2007

In the distribution system, Change of system happens frequently. However, most of the relays are operated manually by a person or not changed when system changed. So, when fault happened, a case that relaydoes not act rapidly happens. Also, in current power system, digital relays are used because of digitization of relay. Digital relay has very many advantages than existing analog relay. One of these advantages is that communication is available and easily can make characteristic curve. If specific values are sent to a relay by communication, A relay can make suitable characteristic curve according to the value. In this paper, by using voltages and currents measured by relay, state of CB(Circuit Breaker) and these relays, SCADA(Supervisory Control And Data Acquisition) system that control and correct characteristic curve of overcurrent relay at system change by using HMI(Human Machine Interface) is proposed.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.3
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• pp.284-290
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• 2000

The measurement of electric current using optical techniques provides a number of important practical advantages including effective isolation from high line potentials and freedom from the saturation effects observed in conventional current transformers. In this work the optical current sensor which uses thin YIG(Yittrium Ion Garnet) film as a Faraday element has been developed. We have characterized this optical current sensor and implemented it to the OOCR(Opto-electronic OverCurrent Realy) Performance of the OOCR shows the possibility of replacing the present overcurrent relays with OOCR.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.195-196
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• 2008

Output of wind generators are changed by windy level. The change of the output also affects the amplitude of fault current. And this fault current causes OCR's mal-operation. To solve the problem, this paper adopts that Over Current Relay adapted for Decentralized generator algorithm.