• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.196-198
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• 2020

본 논문은 SiC MOSFET의 단락 검출을 위한 고정밀 Rogowski 코일 회로 설계 방법을 제안한다. 설계 방법을 제안하기 위해 먼저 Rogowski 코일의 기본 구성인 적분기를 실제 시스템 요구 사양에 맞추어 설계한다. 설계한 회로의 성능 확인을 위하여 DPT (double pulse test)를 실시하며, test 결과 분석을 통해 문제점을 파악하고 전류 센싱 정밀도 향상을 위해 입출력 필터 설계 및 Rogowski 코일 턴 수를 변경한다. 변경한 각 조건들에 대하여 DPT를 진행하고 각 test 결과를 기반으로 Rogowski 코일 회로 설계 방안을 제안한다.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.466-467
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• 2006

Several synthetic testing methods have widely been used for the performance evaluation of ultra high-voltage circuit breaker. Among these synthetic method, in the paper, capacitance switching testing method which can meet the test requirements and increase the testing capacity has been proposed. This method is made up of two separated sources of short-circuit generator for current source and L-C resonance circuit for voltage source. By using this method, KERI will perform the performance evaluation of capacitive current switching performance for the 800kV GCB(Gas Circuit Breaker).

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.396-397
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• 2015

With the increasing utilization of high-voltage, direct current (HVDC) transmissions in modern power systems, the DC grid is becoming a hot topic in academic and practical systems. In the DC grid, one of the urgent problems is the fast clearance of the DC fault in the DC network. One preferred method is to isolate the faulty point from the DC network in a short time. The DC circuit breaker is to interrupt the overcurrent after DC faults occur. In this paper, a self-excited resonant DC circuit breaker is an easy and cheap equipment to interrupt the DC fault current. The Mayr's arc model is utilized to simulate the self-excited DC circuit breaker in a DC test system in PSCAD/EMTDC.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.327-331
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• 2008

This paper dealt with high speed breaking method to parallel arcing in low-voltage systems. The proposed high speed breaking circuit consists of a Rogowski coil and an integrator, and operates with an earth leakage circuit breaker (ELCB). A parallel arcing state was simulated by a short circuit using stripped wires. In this test, we analyzed tripping characteristics of the circuit breaker by the length of wires from 5m to 30m. From the experimental results, we confirmed that the proposed method can break the parallel arcing within a few millisecond.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.363_364
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• 2009

Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, interaction of electromagnetic force from fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, etc. and close consideration is required for it. This paper presents countermeasures to reduce and release the effect of electromagnetic force with rope binding and installation of spacer and describes its efficacy through three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.624-626
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• 2005

디지털 컴퓨터와 측정시스템의 발달로 대전력시험 데이터들은 시험자에 의한 분석이 아닌, 분석프로그램을 이용한 자동 분석이 가능해 졌다. 그러나 분석 프로그램을 이용하여 시험데이터를 분석해야 할 경우, 분석프로그램의 객관적인 신뢰성이 먼저 확보되어야 한다. 최근 들어 이러한 문제점을 보완하기 위하여, STL(Short-circuit Testing Liason)에서는 분석프로그램의 신뢰성평가를 위해 TDG(Test Data Generator)를 개발하였다. 이를 이용하면 대전력시험기관에서 사용하는 분석프로그램간의 객관적인 비교 및 평가가 가능하다. 따라서 본 논문에서는 STL에서 배포한 TDG를 이용하여, Crest, RMS, %DC 분석프로그램 알고리즘의 신뢰성을 평가해 보았다. 또한, STL에서 제시한 reference curve는 50[Hz]를 기본주파수로 하고 있기 때문에, 평가의 신뢰성을 높이기 위해 본 논문에서는 우리나라의 실정에 맞는 60[Hz]의 reference curve도 추가로 고려하였다. 신뢰성 평가 결과 모든 reference curve에 대한 분석알고리즘의 측정불화도가 STL에서 제시하는 범위에 존재함을 확인하였다.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.113-121
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• 2015

This study aims to examine the risk of electrical fire in places where electric heat wires are used. In general, the use of electric heating wires is becoming more common and prevalent in a bid to prevent increasing damage caused by freezing and bursting in residential water pipes, factory pipes and irrigation pipes in vinyl greenhouse and a variety of heat wire products are available in market with legal safety requirements imposed on them. However, the widespread use of anti-freezing burst heat wire products has caused increasing incidents of fire, which often fail to be incorporated into statistics due to quick onsite extinguishing and insignificant damage although damage is gradually on the rise. Against this backdrop, this study aims to look into the possibility of ignition caused by electric heat wires and the mechanism of how it turns into catching fire through overheat and short circuit tests for anti-freezing burst electrical heat wires (hereinafter called the 'heat wire') and expects to serve as the basis for further observations and analyses on the cause of fire and the process of ignition in a scientific manner.

• Progress in Superconductivity and Cryogenics
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• v.11 no.1
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• pp.25-29
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• 2009

To reduce the power loss in normal state, non-inductively wound high temperature superconducting (HTS) coils are used for fault current limiter (FCL) application. Non-inductively wound coils can be classified into two types: solenoid type and pancake type. These two types have different electrical and thermal and mechanical characteristics due to their winding structure difference. This paper deals with the current limiting characteristics, magnetic field analysis of the two coils. Simulation using finite element method (FEM) was used to analyze the magnetic field distribution and inductance of the coils. Short circuit test using stabilizer-free coated conductor (CC) was also carried out. We can compare the characteristics of the two types of coil by using the data obtained from simulation and short circuit test. We confirmed the feasibility of FCL application by the analysis about the characteristics of non-inductively wound coil using CC.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.5
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• pp.257-263
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• 1999

Recently the performance of CO2 arc welding machine has been advanced significantly through the adoption of inverter circuit topology which made it possible to control the waveform of welding current and thus to suppress the spatter generation. However, the optimum waveform is still uncertain. As a first step for figuring out the promising waveforms, this study was performed to set-up the experimental system for studying the effect of waveform variables, The system designed in this study is a digital controller using single chip microprocessor of 80C196KC. As a result of performance test of this system, it was demonstrated all of the waveform variables could be set individually and the resultant waveforms appeared to be pretty much the same as the intended one.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.306-314
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• 2012

Several numerical or analytical models have been proposed to analyze the thermal response of vertical ground heat exchangers (GHEX). However, most models are valid only after several hours of operation since they neglect the heat capacity of the borehole. Recently, the short time response of the GHEX became important in system simulation to improve efficiency. In this paper, a simple new method to evaluate the short time response of the GHEX by using an analogy model of electric circuit transient analysis was presented. The new transient heat exchanger model adopting the concept of thermal capacitance of the borehole as well as the steady-state thermal resistance showed the transient thermal resistance of the borehole. The model was validated by in-situ thermal response test and then compared with the DST model of the TRNSYS program.