부분방전에 의한 음향신호의 검출과 위치추정에 관한 연구

길경석,박대원,김일권,최수연,박찬용,Kil, Gyung-Suk,Park, Dae-Won,Kim, Il-Kwon,Choi, Su-Yeon,Park, Chan-Yong 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.10

This paper dealt with the frequency spectrum analysis of acoustic signal produced by partial discharge (PD) in insulation oil and the positioning of PD occurrence to apply in diagnosis of oil insulated transformers. Three types of electrode system ; the needle-plane, the plane-plane, and the wire-wire structure were assembled to simulate partial discharges in oil insulated transformers. A low-noise amplifier and a decoupling circuit were designed to detect acoustic signal with high sensitivity The frequency spectrum of the acoustic signal were 50 kHz ${\sim}$ 260 kHz in the needle-plane, 50 kHz ${\sim}$ 250 kHz in the plane-plane, and 45 kHz${\sim}$195 kHz in the wire-wire electrode system. Their peak frequencies were 145 kHz, 130 kHz and 114 kHz, respectively The position of PD occurrence was calculated by the time difference of arrival (TOA) using three acoustic emission (AE) sensors, and we could find the position within the error of 1 % in the experimental apparatus.

저압 유도전동기에서 미소 부분방전 측정에 관한 연구

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 $V_{peak}$.

가스절연개폐기에서 용량성 전압프로브를 이용한 부분방전의 측정

길경석,박대원,최수연,김일권,박찬용,Kil, Gyung-Suk,Park, Dae-Won,Choi, Su-Yeon,Kim, Il-Kwon,Park, Chan-Yong 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.1

An objective of this paper is to develop a partial discharge (PD) measurement device for monitoring gas insulated switches installed in power distribution system. A capacitive voltage probe was studied and designed to detect PD pulse without an electrical connection. The PD measurement device consists of the capacitive voltage probe attached outside of a bushing, a coupling network which attenuates AC voltage by 270 dB, and a low noise amplifier with the gain of 40 dB in ranges of 500 kHz${\sim}$20 MHz. The sensitivity of the prototype device calculated by a calibrator was 1.98 m V /pc. An application experiment was carried out in a 25.8 kV gas insulated switch and the peak pulse of 76.7 pC was detected. From the experimental results, it is expected that the PD measurement device can be applied to online monitoring system of gas insulated switches.

지지애자의 표면오염 모니터링 기술 및 장치

길경석,박대원,정광석,김선재,서동환,Kil, Gyung-Suk,Park, Dae-Won,Jung, Kwang-Seok,Kim, Sun-Jae,Seo, Dong-Hoan 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.5

Line to ground faults by deterioration of insulators has frequently occurred in power system, and the main cause is surface contamination of the insulators. The contamination of insulator is analyzed by monitoring the surface leakage current flowing them. The suspension insulator is monitored by installation of a zero-phase current sensor(ZCT), but the line-post insulator is impossible to apply the same method because of its large diameter structure. This paper proposed a detection method of surface leakage current for a line-post insulator, and it can easily be applied to new and/or built insulators. The leakage current is indirectly calculated from the potential difference between the metal electrode attached on the surface of insulator and the ground connector. To evaluate the performance of the proposed method, the leakage current is compared as a function of contamination condition controlled by the density of NaCl solution. The leakage current is proportioned to the density of NaCl solution, and the voltage detected by the electrode showed the same trend. From the experimental results, we designed and fabricated a monitoring device which is composed of a detection electrode, signal converter, microprocessor, and ZigBee, and its measurement range is $10{\mu}A{\sim}5mA$.

저압용 전기전자기기에 부분방전시험의 적용을 위한 기초연구

길경석,송재용,문승보,차명수,황돈하,강동식,Kil Gyung-Suk,Song Jae-Yong,Moon Seung-Bo,Cha Myung-Soo,Hwang Don-Ha,Kang Dong-Sik 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.6

This paper deals with the application of a partial discharge (PD) test on low-voltage electrical and electronic devices, which is recently being accepted as a non-destructive and a effective dielectric test method. A comparative analysis combined with the Withstand Voltage Test (WVT) specified in IEC standards was carried out on low-voltage insulation transformers. The results showed that the WVT causes insulation degradation of the specimen during the test by applying high voltage. However, the PD test can be performed in ranges from 30 % to 50 % of the test voltage specified in the WVT. Therefore, the PD test is successfully applicable for a non-destructive test method on low-voltage electrical and electronic devices as a replacement of the WVT.

전력선 통신기술을 이용한 조명제어 스위치의 개발

길경석,송재용,문승보,이경수,김창율,Song Jae-yong,Moon Seung-bo,kil Gyung-suk,Lee Gyung-soo,Kim Chang-yul 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.4

본 논문에서는 전력선 통신과 조광 기술을 기반으로 에너지 절약과 적정 조도의 제어가 가능한 조명제어 스위치의 개발에 대하여 기술하였다. 개발된 스위치는 범용의 마이크로프로세서와 주변 전자기술을 이용하며, 하나의 마이크로프로세서로 전력선 통신과 조광기능을 구현함으로서 저가격 상용화가 가능하였다. 캐리어 주파수는 전송 데이터 길이와 신호감쇄를 고려하여 250kHz로 설정하였다. 저압선로에서 시제작품에 대한 시험결과, 본 스위치는 전력선의 길이와 부하용량의 변동에 대해 강인하게 동작하는 것을 확인하였다. Lighting control switches based on the power line communication technology are developed and extended to incorporate dimming control to provide energy saving and appropriate illumination. The developed switch uses a general purpose microprocessor and associated electronics. Both the power line communication and the dimming function are implemented in one microprocessor, and it enables the low price commercialization. The frequency of the carrier was set at 250kHz considering the transmission data length and signal attenuation in power lines. Tests on prototypes in an low-voltage power lines have shown that the switches have a robust operation characteristics with the length of power lines and the variation of load capacities.

광대역 접지임피던스 측정기의 설계 및 제작

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.

유중 부분방전의 음향검출에 관한 연구

길경석,김성욱,박대원,김선재,송재만,Kil, Gyung-Suk,Kim, Sung-Wook,Park, Dae-Won,Kim, Sun-Jae,Song, Jae-Man 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.1

This paper dealt with the acoustic detection of partial discharge (PD) in insulation oil for insulation diagnostics of oil immersed transformers. Electrode systems such as needle to plane, plane to plane, and floating were fabricated to simulate some defects in transformers. A wide band acoustic emission(AE) sensor with the frequency ranges of 100 kHz~1 MHz and a narrow band AE sensor with the resonant frequency of 140 kHz were used in the experiment. Also, a decoupler and an amplifier were designed to detect and amplify the acoustic signal only. The decoupler separates acoustic signal from DC source without any distortion, and the amplifier has the gain of 40 dB in frequency ranges of 11 kHz~4 MHz. In the experiment, frequency components and propagation characteristics of acoustic signal were analyzed, and an algorithm of positioning of PD occurrence by the time difference of arrival was proposed. From the results, the frequency components of the acoustic signal exist from 50 kHz to 200 kHz and the positioning error of PD calculated by three AE sensors was within 1%.

저주파 구동형 집어등용 전자식 안정기 개발

길경석,김일권,송재용,한주섭,신광철,Kil Gyung-suk,Kim Il-kwon,Song Jae-yong,Han Ju-seop,Shin Gwang-chul 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.5

This paper dealt with the design and fabrication of a low frequency electronic ballast for ruh attracting lamps. The proposed electronic ballast was composed of a full-wave rectifier, a step don converter operated as a constant power controled current source, an inverter operated by 130 Hz square wave, and an ignition circuit. An acoustic resonance phenomenon of discharge lamps could be eliminated by application of 130 Hz square wave. Also, a circuit of high voltage pulse generation for lamp ignition was added to the ballast. From the experimental results, voltage and current of the lamp operated by the electronic ballast were estimated 132.5 V and 7.6 A, respectively. and the power consumption was about 1,000 W. The weight of the ballast, which is one of important advantages, was reduced to one-fifth of conventional magnetic ballasts. 본 논문은 저주파 구동형 집어등용 전자식 안정기의 설계 및 제작에 관하여 기술하였다. 제.안한 안정기는 전파 정류회로, 정전력형 전류원으로 동작하는 강압형 컨버터와 130Hz 구형파 발진의 인버터 및 재점등 보호회로로 구성하였다. 램프의 음향공명현상은 130Hz의 저주파 구형 펄스로 제거할 수 있었으며, 램프의 재점등을 위한 고전압 펄스 발생회로를 부가하였다. 실험결과로부터 본 안정기에 의해 구동되는 램프 전압과 전류는 각각 132.5V, 7.6A, 소비전력은 약 1,000 W이었다. 전자식 안정기의 가장 큰 이점으로 중량은 동일 용량의 자기식 안정기에 비해 약 1/5로 감소하였다.

성토시공관리용 방사성 동위원소 이용계기의 측정회로 설계

길경석,송재용,김기준,황주호,송정호 ( Gyung Suk Kil,Jae Yong Song,Ki Joon Kim,Joo Ho Whang,Jung Ho Song ) 한국센서학회 1997 센서학회지 Vol.6 No.5

An objection of this study is to develop a measuring circuit of a gauge using radioisotope for compaction control. The gauge developed in this study makes use of radioisotope with the activity exempted from domestic atomic law and consists of measuring circuits for gamma-rays and thermal neutrons, a high voltage supply unit, and a microprocessor. To obtain meaningful numbers of pulse counts, parallel five and two circuits are provided for gamma-rays and thermal neutrons, respectively. Being simple in electrical characteristics of G-M detector for gamma-rays, pulses are counted through only a shaping circuit. Very small pulses generated from He-3 proportional detector for thermal neutrons are amplified to the maximum of 50 [dB] and a window comparator accepts only pulses with meaning. To minimize effects of natural environmental radiation and electrical noise, circuits are electrostatically shielded and pulses made by ripples are eliminated by taking frequency of high voltage supplied to the circuit and pulse height of ripples into consideration. One-chip microprocessor is applied to process various counts, results are stored and the gauage is made capable to communicate with YC. Enough and meaningful numbers of pulses are counted with the prototype gauage for compaction control.