• 한국전기전자재료학회논문지
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• 제13권6호
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• pp.502-508
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• 2000

In order to detect the partial discharge with the metallic particle in GIS the AE(Acoustic Emission) sensor was designed and simulated by ANSYS 5.5 and manufactured as the coupled vibration mode. The measured resonant frequency and the maximum sensitivity frequency of three coupled AE sensors were as follows ; 147.88 kHz in 8.1mm $\Phi$$\times$8.1mm 128.82 kHz and 58.8 kHz in 9.5 mm$\Phi$$\times$9.5mm, 85.22 kHz and 32.6 kHz in 14.3 mm$\Phi$$\times$14.3 mm, resonant frequency of the AE sensor. The AE sensor of 9.5 mm$\Phi$$\times$9.5mm responded higher than the other coupled vibration mode AE sensor at the partial discharge detection in GIS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.922-924
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• 1998

In this paper, an optical fiber sensor(OF sensor) utilizing the principal of Mach-Zehnder interferometer were proposed to detect the partial discharge signals in insulating oil. At first the AC breakdown signals were detected to check the response of the OF sensor. The detected signals from OF sensor was consistent with that from current probe. After the response checking, simultaneous measurements and continuous recording were made of electrical and the OF sensor signals from partial discharge(PD) produced by IEC(b) electrode system immersed in insulating oil. The continuous recording made it possible to extract basic quantities of PD from the OF sensor signals, such as pulse phase and pulse amplitude distribution. Through the signal analysis, the absolute peaks of the OF sensor PD signal was found to be increased with the amplitude of electrical signals, and these results mean that there is a strong correlation between OF sensor and electrical PD signals. It was demonstrated that the OF sensor in this research had a possibility to detect the PD signals in power apparatus.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.286-289
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• 1999

In order to detect the partial discharge with the metallic particle in GIS, AE sensor was designed and simulated by ANSYS, and manufactured as the coupled vibration mode. The resonant frequency of three Coupled AE sensors were as follows ; 147.88 kHz in 8.1 mm$\Phi$ $\times$ 8.1mm, 128.82 kHz in 9.5 mm$\Phi$ $\times$ 9.5mm, 85.22 kHz in 14.3mm$\Phi$ $\times$14.3mm. That frequency is λ/2 resonant frequency. AE sensor of 9.5mm$\Phi$ $\times$9.5mm responded higher than the other coupled vibration mode AE sensor at the partial discharge detection in GIS.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.383-387
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• 2010

The response characteristics of AE (acoustic emission) sensors with a coupled vibration mode and a non-coupled vibration mode were investigated according to PD(partial discharge) quantities in XLPE (cross linked polyethylene) sheets and craft papers immersed in insulating oil. The response voltages of a coupled vibration mode AE sensor were linearly proportional to the PD quantities up to 1,000 pC in XLPE sheets, while a non-coupled vibration mode AE sensor did not show the similar linearity. In case of a test of craft papers immersed in insulating oil, a linearity between response voltages and PD quantities was observed up to 550 pC, but after that, similar linearity between response voltage of any types of AE sensor and PD quantities was not shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.147-148
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• 2008

In this paper two kinds of techniques were compared for localization of PD(partial discharge) in power transformer and more useful method was suggested. Both of them, the time of arrival and the energy content method, were tested in 154kV single phase experimental transformer using UHF signal measurement. The former was using the difference of arrival time of recorded signals from four UHF sensors, the latter was based on the energy content in frequency spectra of signals detected at all sensors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.163-164
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• 2007

In this study, we developed intelligent spacer built in the internal type UHF PD sensors. 3-Dimensional electro-magnetic simulations were performed to analyze electric-field distribution of the single-phase GIS and three-phase GIS. After considering the spacer's specification, Sensor structures were designed and analyzed using the 3-D EM Simulator. As a result of the simulation the internal type UHF PD sensors were built in. Performance of the sensor built into real scale GIS spacer was measured in terms of return loss and detected Max voltage. And we identified a character of the intelligent spacer by using 5pC partial discharge ceil.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.161-162
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• 2007

This paper is analyzed the internal type UHF sensors that be able to monitor the condition of the distribution facilities and the location selecting of that sensors. It set the PD cell on the inside of 22.9kV load switchgear and then it executed Partial Discharge test. it introduced the result of the test.

• 전기학회논문지
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• 제56권6호
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• pp.1092-1098
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• 2007

Since one decade, the detection of HFPD (High frequency Partial Discharge) has been proposed as one of the effective method for the diagnosis of the power component under service in power grids. As a tool for HFPD detection, Metal Foil sensor based on the embedded technology has been commercialized for mainly power cable due to its advantages. Recently, for the on-site noise discrimination, several PA (Pulse analysis) methods have been reported and the related software, such as Neural Network and Fuzzy, have been proposed to separate the PD (Partial Discharge) signals from the noises since their wave shapes are completely different from each other. On the other hand, the relevant fundamental investigation has not yet clearly made while it is reported that the effectiveness of the current methods based on PA is dependant on the types of sensors. Moreover, regarding the identification of the vital defects introducible into the Power Cable, the direct identification of the nature of defects from the PD signals through Metal Foil coupler has not yet been realized. As a trial for solving above shortcomings, different types of software have been proposed and employed without any convincing probability of identification. In this regards, our novel algorithm 'PA Map' based on the pulse analysis is suggested to identify directly the defects inside the power cable from the HFPD signals which is output of the HFCT and metal foil sensors. This method enables to discriminate the noise and then to make the data analysis related to the PD signals. For the purpose, the HFPD detection and PA (Pulse Analysis) system have been developed and then the effect of noise discrimination has been investigated by use of the artificial defects using real scale mockup. Throughout these works, our system is proved to be capable of separating the small void discharges among the very large noises such as big air corona and ground floating discharges at the on-site as well as of identifying the concerned defects.

• 한국조명전기설비학회지:조명전기설비
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• 제8권2호
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• pp.46-53
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• 1994

본 논문에서는 초음파 센서를 이용하여 부분방전에 의해 발생하는 기준준위 이상의 초음파 펄스수를 계수하여, 전력용 변압기의 부분방전 진전을 상시 감시할 수 있는 예방진단기술에 관하여 연구하였다. 실험결과, 초음파 발생장치 및 침-평판전극에 일정전압을 인가하여 일정한 초음파 및 부분방전을 발생시킬 경우에 측정한 초음파 펄스수의 경향은 일정하였으며, 침-평판전극에 인가전압을 상승시켜 부분방전을 임의로 크게 하거나, 침-평판전극에 절연지를 삽입하고 일정전압을 인가하여 부분방전을 진전시킬 경우의 초음파 펄스수는 부분방전의 진전과 더불어 증가함을 보여, 본 연구에서 제시한 진단장치를 이용하여 부분방전의 진전을 상시 감시할 수 있음을 확인하였다.

• 한국전기전자재료학회논문지
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• 제29권2호
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• pp.114-119
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• 2016

This paper dealt with the propagation characteristics of acoustic signal in insulation oil for the purpose of improving the reliability of AE (acoustic emission) method used for condition monitoring of oil-immersed transformers. A discharge source was placed in insulation oil and AE sensors ($f_c$ :140 kHz) were attached on the oil tank to study the changes of velocity and propagation path with the depth and distance. The average velocity was 1,436 m/s and the velocity decreased with the increase of depth from the oil surface to 430 mm. The propagation paths were classified into three sections by the shortest reflection path of the detected signal. The minimum distinguishable distance in each section was 70 mm. It was also verified that PD (partial discharge) with a magnitude over than 500 pC can be detected by the AE sensors.