• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.132-135
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• 2004

In generally, compared with VHF band, electromagnetic waves of UHF band have a low influence for external noise. We can detect the real abnormality with several pC in GIS using UHF method. Recently, it has applied to use the external UHF sensor attached on spacer to GIS of existing substation. In this paper, we firstly described the technique of the partial discharge measurement using frequency analysis and phase analysis in UHF band. Secondly, we presented the results of sensitivity, the relationship of dBm-pC and diagnosis of the reason of PD source by phase analysis. And then, we report the diagnosis result of partial discharge on 800kV GIS in domestic substation. rge diagnosis of GIS.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1655-1657
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• 2002

Ultra-wide bandwidth (UWB), narrow bandwidth (single frequency), and a combination of both technologies have been studied for the ultra-high frequency (UHF) partial discharge (PD) monitoring system as a detection scheme. We have experimentally compared those detection methods using a mock-up of 362 kV class single phase gas-insulated switchgear (GIS) and a stable PD source. A rolling-ball type PD cell that produces PDs of about 10 pC, is placed at one end of the GIS. An internal UHF PD sensor was attached several meters away from the PD source. The PD spectrum was measured up to 3 GHz. A useable bandwidth of more than 1 GHz was used to measure UWB signals from the PD. To simulate the narrow bandwidth scheme a bandwidth of 100 kHz centered at several different frequencies was used.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.516-518
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• 2000

정상 상태의 gas-insulated switchgear (CIS) 내부에서 발생한 부분방전 신호를 검출 할 수 있는 UHF 부분방전 검출 센서를 실험용 362 kV GIS에 적용하였다. GIS 내부에 알루미늄 이물질을 투입한 다음 120 - 180 kVrms 전압을 단계적으로 인가하고 장시간 인가전압 위상에 대한 UHF 부분방전 신호를 측정하였다. 인가전압을 높일수록 검출된 방전신호의 간격이 늘어났으며, 이물질로 사용한 알루미늄선의 길이가 길어질수록 이물질의 상승고도는 증가하였다. GIS 내부에서 이물질의 운동에 대한 간단한 계산에서도 비슷한 경향을 보임을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2119-2124
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• 2008

An information-oriented basis in today's society has been changing fast, and the desire for connectivity has caused an exponential growth in wireless communication and sensor network. Sensor networks using RFID, in particular, have led this trend due to the increasing exchange of data in Ubiquitous such as the home RF, access control system, U-Healthcare, and Logistics information Systems. Also, the RFID when it applies a technique, is able to raise the stability of shipping as controling the mobile course and an entrance and exit of the crews an well as previously preventing an accident from shipping. In this paper, we designed and implemented personnel control system using UHF-RFID in vessels which shows through host PC reading and writing tag.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.805-810
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• 2011

This paper deals with the method and algorithm used to find fault locations in gas insulated transmission line. The method uses UHF sensors and digital oscilloscope to detect discharge signals emitted to the outside through insulating spacer in the event of breakdown inside GIL. UHF sensors are the external type and installed at outside of insulating spacers of GIL. And we used wavelet signal processing to analyze the discharge signals and confirm the exact fault location findings in the GIL test line. This method can overcome demerit of TDR(Time Domain Reflectometer) method having been applied to detect fault location for conventional underground transmission lines, and Ground Fault Sensors used in conventional GIS systems. TDR method requires high level of specialty and experience in analyzing the measured signals. Ground fault sensors are installed inside GIL and can be destroyed by high transient voltage. This paper's method can simplify the fault location process and minimize the damage of sensors. In addition, this method can estimate the fault location only by the time difference when discharge signals are arrived to detecting sensors at the ends of GIL sections without reasons of breakdown. To test the performance of our method, we installed sensors at the ends of test line of GIL(84m) and sensed discharge signals occurred in GIL, energized with AC voltage generator up to 700kV.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2063-2064
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• 2011

UHF PD sensor has some disadvantages in measuring void discharges due to their frequency characteristics lower than 300MHz. Therefore, in this study, the possibility of VHF sensor in measuring partial discharges(PD) in GIS was investigated using simulated experiments. As a result, by installing VHF sensors to the copper bus of the encloser in GIS, it is confirmed that partial discharges could be perfectly detected, which means that VHF PD measuring technique can be the alternative of UHF PD method.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.161-165
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• 2006

In this paper, we developed HPF (high pass filter) consists of lumped LC components to decrease the noises that are detected in PD (partial discharge) measuring test, and adapted it to field test. We tested it under laboratory circumstances like the fields, and measured the phase change properties of detected signal in UHF sensor with Lemke Probe and oscilloscope (TDS-3054, Tektronix). As a result, we obtained available data showing the decrease of noises in the experiments with the developed HPF from the joint box of 22.9kV distribution line. The result can be adapted to prevent the degeneration of the XLPE power cable, and to observe and diagnosis the underground power transmission cable at the ultra-high voltage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.832-835
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• 2008

An information-oriented basis in today's society has been changing fast, and the desire for connectivity has caused an exponential growth in wireless communication and sensor network. Sensor networks using RFID, in particular, have led this trend due to the increasing exchange of data in Ubiquitous such as the home RF, access control system, U-Healthcare, and Logistics information Systems. Also, the RFID when it applies a technique, is able to raise the stability of shipping as controling the mobile course and an entrance and exit of the crews an well as previously preventing an accident from shipping. In this paper, we designed and implemented personnel control system using UHF-RFID in vessels which shows through host PC reading and writing tag.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1891-1893
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• 2004

이 논무에서는 유입식 변압를 대상으로 UHF 대역의 펄스신호를 검출하는 센서를 소개하고, 이를 이용한 방전 결함별 측정 결과를 소개한다. 측정결과는 기존의 PRPD법과 주파수 Domain과 위상 Domain에 대한 정보를 가지는 p-f-q 분석으로 측정 하였으며, 본 논문에서는 후자의 결과를 중심으로 서술 하였다.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1835-1837
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• 2004

The UHF electromagnetic waves excited by PD pulses propagate along the GIS busbar not only TEM mode, but also TE and TM mode. Generally the waves detected by the UHF sensors are those of high order modes and such waves can only propagate the higher than cut-off frequency. In this paper, computed cut-off frequency of 362[kV] GIS by each modes and simulated electromagnetic field of each propagation modes by FEM(Finite Element Method) program. Frequency band of each TEmn/TMmn modes were determinated by simulation results and were discussed optimal position of UHF sensor from this results.