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길경석,송재용,김일권 한국센서학회 2000 센서학회지 Vol.9 No.2
This paper dealt with the developed portable electric field meter which consisted of planar-type sensor, analog amplifier with gain controller, A/D convertor, and display unit. The principle of the planar-type sensor for detecting time-varying electric field of extremely low frequency (ELF) bandwidth was described, and a calibration system using cylindrical guard electrodes and parallel-plate electrodes was proposed. From the calibration experiment, the frequency bandwidth and the sensitivity of the developed electric field meter was 17 [Hz) ∼ 7 [kHz], and 4.45 [mV/V/m], respectively. Also it can measure the electric field strength up to 10 [kV/m], and the measured result was displayed on the liquid crystal display in digit. The electric field meter can be widely applied to measure electric field strength radiated from power lines, computers, and home appliances such as hair dryer, heater, etc..
길경석,박대원,장운용,한주섭,길형준,Kil, Gyung-Suk,Park, Dae-Won,Jang, Un-Yong,Han, Ju-Seop,Gil, Hyoung-Jun 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.10
The basic performance of the ground system is evaluated as the ground resistance by applying low frequency current below 1 kHz. However, characteristics of the ground system should be analyzed by high frequency current up to 1 MHz since transient currents having a few hundred kHz component flow during a line-to-ground fault and/or a lightning strike. This paper deals with the design and fabrication of a wideband ground impedance meter (WGIM) which measures the impedance of ground systems in ranges from 65 Hz to 1.28 MHz. Also, a noise elimination algorithm using a digital bandpass filter is proposed. The maximum error of the WGIM is 4.91% in the measurement frequency range.
길경석 한국전기기술인협회 1999 電力技術人 Vol.205 No.9
건축물의 대형화, 정보화, 자동화 등으로 전력수요가 급증하면서 전력설비가 대용량화되고 복잡해져서 한 순간이라도 정전이 발생하면 유, 무형의 경제적 손실이 따르게 된다. 이와 같은 배경에서 과거보다도 전력설비의 고안정도, 고신뢰성이 한층 요구되고 있으며 특히 수, 변전설비에 대한 안전관리의 중요성이 날로 부각되고 있는 실정이다.
길경석,송재용,이종혁,권장우,송동영 한국조명전기설비학회 2000 조명·전기설비학회논문지 Vol.14 No.6
본 논문에서는 과도전압과 전원선 방해파로부터 가전기기틀 안전하게 보호할 수 있는 전자파 대용 단위세대 분전반의 설계 및 제작에 대하에 기술하였다. 제안한 분전반은 바리스터, 캐패시터 및 간선도채의 인덕턴스로 구성한 과도전업 차단장치와 전자파 필터를 내장하고 있다. 시제작한 분전반은 IEC 규격의 조합형 서지 발생장치와 회로밍 분석키를 이용하여, 과도전압에 대한차단특성과 전원선 방해파의 감쇠특성을 평가하였다. 실험 결과로부E] 본 연구에서 제안한 분전빈은 IEC 61000-4-5에 규정한 서지내생기준을 만족하였으며, 150[kHz]-30[MHz] 대역의 전원선 방해파에 대해 20[dB] 이상의 감소효과를 나타내었다. This paper describes the design and fabrication of a home-panel board for electromagnetic compatibility which can protect home-electric appliances from transient voltages and power line noise. The proposed panel board include a transient voltage blocking device and a EMI filter which consisted of varistors, capacitors, and bus line inductance.A performance test of the prototype panel board, blocking characteristics to transient voltages and reduction characteristics to power line noise, are carried out by using a combination surge generator standardized in IEC and a network analyzer.The results showed that the proposed panel board is satisfied with the surge immunity level of IEC 61000-4-5, and has an over 20[dB] noise reduction performance in ranges from 150[kHz]∼30[MHz].
길경석,송재용,서황동,황돈하,강동식,김용주,Kil, Gyung-Suk,Song, Jae-Yong,Seo, Hwang-Dong,Hwang, Don-Ha,Kang, Dong-Sik,Kim, Yong-Joo 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.10
In this paper, we dealt with a partial discharge(PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage electric and electronic devices. The PD measurement system Is composed of a coupling network, a low noise amplifier, and associated electronics. h shielded box Is adopted to make a better measurement environment against around noise. A low cut-off frequency of the coupling network estimated by a sinusoidal wave input was 125 kHz (-3 dB). Calibration tests on laboratory set-up have shown that the PD measurement system has a stable sensitivity of 10 mV/pC. In an application test oil a low-voltage three phase Induction motor (5 HP), we could detect 0.53 pC level of partial discharge at the applied voltage of AC 650 $V_{peak}$.
길경석,박대원,김성욱,박찬용,조영진,Kill, Gyung-Suk,Park, Dae-Won,Kim, Sung-Wook,Park, Chan-Yong,Cho, Young-Jin 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.6
In this paper, the safety for passengers of composite car-body against lightning strikes was analyzed by the application of an impulse generator which can produce impulse current up to 50 kA with 8/$20{\mu}s$ waveform. Potential difference on inside surface of the car-body was measured as a safety parameter for the passengers against lightning strikes. The potential difference between 20 em distant was 175 V at 37.67 kA, and it corresponds to 875 V between 1 m distant. The amount of charge flowing a passenger at 100 kA impulse current can be estimated to $0.31\;mA{\cdot}s$. This is much less than the limit amount of charge for human body, $30\;mA{\cdot}s$ which is presented by Koeppen and Osypka.
길경석,문승보,박태곤,한주섭,송재용,서황동 대한전기학회 2005 전기학회논문지C Vol.54 No.8(C)
In this paper, surface temperatures of ZnO arresters as a function of ambient temperatures and leakage currents were experimentally investigated. The variations of the leakage current was below 10㎂, which comes about 4.5% of the normal leakage current. Temperature differences between the ambient and the surface of arresters were not shown until 150% to the normal leakage current, and were remarkable over 200%.From the results, we deduced a couple of polynomials which enables the calculation of the leakage current by the measurement of surface temperature. Tests on used arresters have shown the same results as the experimental one. Also, we expect that an arrester diagnosis is possible by measuring the surface temperature of them after more studies on the effect of wind, moisture penetration, and arrester types.
길경석,류길수,송재용,김일권,박대원,한문섭 한국철도학회 2007 한국철도학회논문집 Vol.10 No.2
In this paper, we proposed a selection and application recommendations of ZnO arresters for DC electric traction vehicles. To decide the Continuous Operating Voltage(UC), the Rated Voltage(Ur), and the Nominal Discharge Current(In), we measured and analyzed system voltages and surge currents flowing the arrester installed on a DC electric traction vehicle under running state. System voltages measured up to 1,800V in 1,500V-system, and surge currents were recorded up to 3 times per a running-service-route and their magnitudes were ranges of 150A~2kA. From these results and a standard EN50163, we could proposed UC, Ur, and In available for the 1,500VDC electric traction vehicles.
길경석,김일권,박대원,송재용,이강원,조은제 한국철도학회 2007 한국철도학회논문집 Vol.10 No.4
A new dielectric test on main relays of electric traction vehicles, the partial discharge(PD) test, is proposed. The PD test will not affect the insulation performance of specimen during the test and provide much more detailed information on insulation, the types of defects, and so on. Insulation performance of relays is estimated by discharge inception voltage(DIV), discharge extinction voltage (DEV), and apparent charge as a function of test voltage and time. Three main relays of different manufacturing date were estimated by applying AC voltage with three patterns in ranges of 0~1,200[V]. From the results, we could estimate insulation state and which types of defects exist in them.