• Title, Summary, Keyword: Partial discharge

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Properties of On-Line Partial Discharge in Hydrogenerator Stator Windings (수력발전기 고정자 권선의 운전중 부분방전 특성)

  • Kim, Byong-Han;Kim, Hee-Dong
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.4
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    • pp.172-177
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    • 2006
  • During normal machine operation, partial discharge(PD) tests were performed with partial discharge analyzer(PDA) in two hydrogenerators. Six cable couplers were installed in circuit ring bus and endwinding of three phases. PDA showed that the normalized quantity number(NQN) and the partial discharge magnitude$(Q_m)$ were very low in hydrogenerator #1 and #2, respectively. The trend analyses of NQN and $Q_m$ value are available for monitoring of the insulation condition in hydrogenerator stator windings. The insulation condition of stator winding can be assessed. Discharge at conductor surface was discovered in B phase(C2 coupler) of hydrogenerator #1. Internal discharges were generated in A and C phases(C2 coupler) of hydrogenerator #1 and in A, Band C phases(C1 and C2 couplers) of hydrogenerator #2. Slot discharges occurred in A, Band C phases(C1 coupler) of hydrogenerator #1. The stator windings of two hydrogenerators were in good condition.

A Study on the Effect of Pressure upon A.C Partial Discharge in Insulating Oil (제어유의 문류품분효전에 미치는 형력의 영향)

  • Sang-Hoon Kook
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.32 no.7
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    • pp.227-233
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    • 1983
  • Noticing that action of gaseous phase in insulating oil concerns to the discharging characteristics, I investigated the smalness pressure effects on quantity of the partial discharge and discharging pulse frequency. Tests are carried out between the niddle points in insulating oil at pressure being changed by gradual charge of inert gas Ar. At pressure as low as of 0.1-0.5 torr pulse frequency and maximum partial discharge reach peak while at pressure haigher than 20 torr no pulse is observed. The fact that pulse frequency has peak value at certain presure, which is changed either by charging Ar or by adding oil, implies that the action of gaseous phase depends on pressure. Test results are that partial discharge pulse are governed by pressure of Ar-charged oil, and less partial discharge pulses correspond to smaller bubbles whereas more partial descharge pulses correspond to larger bubbles.

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The Electric Fields Characteristics of Partial Discharges in $SF_6$ ($SF_6$ 가스중 부분방전시 전계 특징)

  • 김해준;박경태;박광서;이현동;김충년;이광식
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.145-149
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    • 2001
  • The most of faults in gas insulation of power facilities are caused by partial discharge. Therefore we simulated partial discharge and measured the radiated electromagnetic wave emitted from partial discharge in SF$_{6}$ gas by biconical antenna. This paper describes time delay and electric fields pulse characteristics of radiated electromagnetic waves with distance(1[m], 3[m], 5[m]) between antenna and discharge source.e.

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Acoustic Signal Analysis to Discriminate Partial Discharge Sources (부분방전원에 따른 초음파신호 특성분석)

  • Lee, Y.H.;Park, S.H.;Lee, K.W.;Lee, Y.H.;Kang, S.H.;Lim, K.J.
    • Proceedings of the KIEE Conference
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    • pp.1691-1693
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    • 2002
  • Acoustic partial discharge detection has been used on GIS testing for more than 10 years. Sensitivities show that most of critical defect types can be detected with a reasonable signal-to-noise ratio. The paper reports on acoustic partial discharge detection comparable to sensitive electrical PD(partial discharge) measuring method.

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Development of a platform based on JAVA for partial discharge monitoring (부분방전 광역감시를 위한 JAVA기반 진단플랫폼 개발)

  • Jeon, Jin-Hong;Kim, Kwang-Su;Jeong, Jun-Young;Kim, Kwang-Hwa
    • Proceedings of the KIEE Conference
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    • pp.423-425
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    • 2004
  • This raper deals with a platform for diagnosis monitoring of partial discharge based on Java virtual machine. This platform is designed for estimating diagnostic parameters of partial discharge signal and displaying Web-page on operating status. For Web-service, hardware of platform is based on a Strongarm processor and software base is designed on Linux and java virtual machine.

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Partial Discharge Characteristics of the XLPE/EPDM Interface in Power Cable Joint (전력케이블 접속재 XLPE/EPDM 계면의 부분방전 특성)

  • Cho, Kyung-Soon;Hong, Jin-Woong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.9
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    • pp.780-786
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    • 2007
  • This paper describes the influence on partial discharge characteristics of defects at the model XLPE/EPDM interfaces of power cable joints. The defects of void and copper which could inadvertently be present at the joint interface. We measured ${\Phi}-n,\;{\Phi}-q$ patterns by a computer-aided partial discharge measuring system. Several parameters i, e, maximum discharge $q_{max}$ [pC], average discharge q [pC/cycle], and average angle of discharge ${\Theta}g$ [deg] were found to depend upon the defect type varying applied voltage. As the result of time evaluation, partial discharges are small different at copper defects, but is decreasing obviously about 20 minutes at void defect. It considered that difference of magnitude of total positive discharge of Q+ [pC] and total negative discharge of Q- [pC] is SPMD(swarming pulsive micro discharges).

UHF Sensor Development for Partial Discharge Exclusively for Measurement in 25.8kV GIS (25.8kV GIS 부분방전 측정전용 UHF센서 개발)

  • Choi, Mun-Gyu;Cha, Hanju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.6
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    • pp.1083-1088
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    • 2016
  • 25.8kV GIS part generated by sensors to measure contact an inflow of noise depending on the extent of the measured discharge occurs often not easy. Partial discharge signal measurement sensor suitable for developing a more useful measurements at the scene to this, partial discharge waveform analysis developed a sensor, and to utilize forSensor on the development of the most important is VSWR decided to (voltage standing wave ratio) voltage standing-wave ratio less than 1.5 and decided less than at the full spectrum bands that are measured, this time Return loss, as measured value by absolute criteria 14.0 dB produced the sensor, designed to or more. UHF 1.5~0.5 GHz bandwidth spectrum to be measured in GIS. UHF bands were designed to be able to measure the best signal. Recently, 25.8kV GIS production company has been increasing variety of GIS were made open spacer in partial discharge in accordance with the not very easy to detect the signal. The sensor is designed height of four cm external spacer is attachment GIS in an influx of outside noise measurement, and be so manufactured as to facilitate the least we've done. Also, since partial discharge which occur can measure the frequency of the 170kV GIS external partial-discharge signals that occur at the scene of insulation applied to the spacer. Features, and also derived good results using global positioning. Also measured discharge point about sensors that are stable and the reliability of the development and local substation equipment failure occurring signal analysis through the discharge for the prevention of widely. There should be to believe that used.

Classification Technique of Kaolin Contaminants Degree for Polymer Insulator using Electromagnetic Wave (방사전자파를 이용한 고분자애자의 오손량 분류기법)

  • Park Jae-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.2
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    • pp.162-168
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    • 2006
  • Recently, diagnosis techniques have been investigated to detect a Partial Discharge associated with a dielectric material defect in a high voltage electrical apparatus, However, the properties of detection technique of Partial Discharge aren't completely understood because the physical process of Partial Discharge. Therefore, this paper analyzes the process on surface discharge of polymer insulator using wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time~frequency domain. As it is important to develop a non-contact method for detecting the kaolin contamination degree, this research analyzes the electromagnetic waves emitted from Partial Discharge using wavelet transform. This result experimentally shows the process of Partial Discharge as a two-dimensional distribution in the time-frequency domain. Feature extraction parameter namely, maximum and average of wavelet coefficients values, wavelet coefficients value at the point of $95\%$ in a histogram and number of maximum wavelet coefficient have used electromagnetic wave signals as input signals in the preprocessing process of neural networks in order to identify kaolin contamination rates. As result, root sum square error was produced by the test with a learning of neural networks obtained 0.00828.

Characteristics of Ultra High Frequency Partial Discharge Signals of Turn to Turn Defect in Transformer Oil (절연유 내 변압기 Turn간 결함에 의한 부분방전의 극초단파 전자기파 신호 특성)

  • Yoon, Jin-Yul;Ju, Hyung-Jun;Goo, Sun-Geun;Park, Ki-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.2000-2004
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    • 2009
  • In general, for the condition monitoring of a power transformer using the UHF PD measuring technique, detection of any partial discharge, identifying the defect in the transformer and locating the insulation defect are necessary. In this paper one of the most frequent detects which can result in turn to turn fault in power transformer was examined for identifying the defect. In order to model the defect, as a discharge source, a partial discharge cell was used for experimental activity. Magnitude of electromagnetic wave signals and corresponding amount of apparent discharge were measured simultaneously against phase of applied voltage to the discharge cell. Frequency range and phase resolved partial discharge signals were measured and analyzed. The results will be contributed to build the defect database of power transformer and to decrease the occurrence of transformer faults.