• Title/Summary/Keyword: PD magnitude

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Analysis of On-Line Partial Discharge in High Voltage Motor Stator Windings (고압전동기 고정자 권선의 운전중 부분방전 분석)

  • Lee, Sang-Kil;Kim, Hee-Dong;Kim, Kwang-Hun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05c
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    • pp.152-155
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    • 2002
  • During normal operation, partial discharge(PD) tests were performed using turbine generator analyzer(TGA) in high voltage motor. Epoxy-mica couplers are installed at motor terminal and analyzed PD signal using TGA. #A motor stator insulation is good because small partial discharges are detected PD pattern show that PD occurs in insulation. PD of #B motor is larger than that of #A motor and PD pattern show that positive PD larger than negative PD. It means that PD occurs between insulation and slot. And A phase PD magnitude of #B motor is large and high compare with any other phase. Therefore wedge, core and slot of #B motor need to check and repair.

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Analysis of On-Line Partial Discharge in High Voltage Motor Stator Windings (고압전동기 고정자 권선의 운전중 부분방전 분석)

  • Lee, Sang-Kil;Kim, Hee-Dong;Kim, Kwang-Hun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05c
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    • pp.199-202
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    • 2002
  • During normal operation, partial discharge(PD) tests were performed using turbine generator analyzer(TGA) in high voltage motor. Epoxy-mica couplers are installed at motor terminal and analyzed PD signal using TGA. #A motor stator insulation is good because small partial discharges are detected. PD pattern show that PD occurs in insulation. PD of #B motor is larger than that of #A motor and PD pattern show that positive PD larger than negative PD. It means that PD occurs between insulation and slot. And A phase PD magnitude of #B motor is large and high compare with any other phase. Therefore wedge, core and slot of #B motor need to check and repair.

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Detection of Partial Discharges by a Monopole Antenna in Insulation Oil (모노폴 안테나를 이용한 유중 부분방전의 검출)

  • Park, Dae-Won;Lee, Jung-Yoon;Kil, Gyung-Suk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.9
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    • pp.727-731
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    • 2012
  • This paper dealt with the measurement and analysis of electromagnetic waves radiated from a partial discharge (PD) source in insulation oil to apply condition monitoring of oil-immersed transformers. Two types of narrow-band monopole antennas with the resonant frequency of a 500 MHz and a 1 GHz were designed and fabricated. Also, a needle-plane electrode system was manufactured to simulate PDs and the curvature radius of the needle is 10 ${\mu}m$ and the diameter of the plane is 60 mm. Electromagnetic wave was measured by the PD measurement system with the monopole antennas. Detection sensitivity of the fabricated antenna was compared for the same PD magnitude; 620 $mV_{peak}$ for the 500 MHz antenna and 960 $mV_{peak}$ for the 1 GHz antenna to the PD magnitude of 74 pC. Consequently, the 1 GHz monopole antenna is more effective to detect PDs in oil-immersed transformers.

The Characteristics of Electromagnetic waves by surface discharge in solid insulator (고체절연체의 연면방전에 따른 방사전자파 분포 특성)

  • Kim, Chung-Hyun;Lee, Hyun-Dong;Kim, Ki-Chai;Park, Won-Zoo;Lee, Kwang-Sik;Lee, Dong-In;Lee, Chun-Ha
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1862-1864
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    • 2000
  • Recently diagnostic techniques have been investigated to detect a partial discharge(PD) associated with a dielectric material defect in a high-voltage electrical apparatus. Among the PD measuring method, detecting electromagnetic wave generated by PD is one of the most effective method because PD radiates wide frequency of electromagnetic wave up to UHF. From the above points of view, we have investigated the polarization and distance characteristics of electromagnetic wave radiated by an insertion of solid insulators between needle-plane electrodes in the air. According to the magnitude of applied voltage, the frequency spectrum of radiated electromagnetic waves were increased about under 100(MHz), compared with background noise. The electromagnetic wave magnitude is attenuated about 4$\sim$7.6[dB] at the point 3[m] away from PD.

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On-Line and Off-Line Partial Discharge Properties in the Pumped Storage Generator Stator Windings (양수발전기 고정자 권선에서 운전중 및 정지중 부분방전 특성)

  • Kim, Hee-Dong;Ju, Young-Ho;Yoon, Dea-Hen
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2089-2092
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    • 1999
  • Partial discharge(PD) tests were performed both when the pumped storage generator(rated 13.8kV and 220MVA) was on-line and off-line. This generator has been equipped with 12 bus coupler sensors in directional mode. PD tests were conducted using partial discharge analyzer(PDA), partial discharge meter(PDM) and digital partial discharge detector. PDA showed that the patterns of the normalized quantity number(NQN) and the partial discharge magnitude are in accord with on-line and off-line. The insulation condition was estimated by diagnostic tests(off-line) such as PD magnitude and dissipation factor.

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Properties on the Distribution Pattern of Discharge Signals Generated in the Power Cable (전력 케이블에서 발생되는 방전 신호의 분포패턴에 관한 특성 분석)

  • 소순열;홍경진;이우기;이동인;김태성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.13-18
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    • 1998
  • After Computer-based PD measurement was referred in the 1970's, the new technology and a number of digital system have been studied. And the selection of PD patterns, extraction of relevant information for PD recognition are discussed because the number of pulse as a function of discharge magnitude and discharge pulse as a function of the power frequency cycl4e offer the information of the aging insulation. This paper investigates the discharge phase($\phi$) and magnitude(q), as well as the number of discharge(n) with regard to discharge signals generated in power cable. Therefore, according to properties analysis on the distribution of $\phi$ , q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.

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Analysis of PD Characteristics by Types of Insulation Defects in Power Cables (전력케이블의 절연결함에 따른 부분방전 특성분석)

  • Choi, Jae-Sung;Park, Chan-Yong;Kim, Sun-Jae;Han, Ju-Seop;Kil, Gyung-Suk
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.1977-1983
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    • 2009
  • This paper described partial discharge(PD) patterns depending on types of insulation defects in CNCO-W cable(Concentric Neutral Closs-linked Polyethylene Insulated Polyolefin-Water Proof Sheathed Power Cable). The PD measurement system consists of a coupling network, a detection impedance, and a low noise amplifier. A 16 bit, 250 MS/s data acquisition system was used to analyze PD patterns. To simulate insulation defects in a power cable, a needle with the curvature radius of $10{\mu}m$ was inserted into the insulation part. We measured phase ($\Phi$), magnitude (q), and counts (n) of PD pulse for the defects, and classified PD patterns using the PRPD (phase Resolved Partial Discharge) method. From the analysis of acquired PD signals, we could find that a unique PD pattern is formed according to the types of defect.

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Analysis of Insulation Aging in Operating High Voltage Motors (운전중인 고압전동기에서 절연열화 분석)

  • Kim, Hee-Dong;Ju, Young-Ho
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2175-2178
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    • 2005
  • During normal machine operation, partial discharge(PD) measurements were performed with turbine generator analyzer(TGA) in five high voltage motors(rated 6.6kV). These high voltage motors were installed with 80pF capacitive couplers at the terminal box. The PD patterns were displayed two dimensional and three dimensional. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). Off-line PD measurements were conducted on five motors. These motors were energized to 3.81kV. The PD levels in pC were measured with a conventional digital PD detector. The comparison of positive to negative PD indicates whether the defect elements of PD are within the insulation or on the insulation surface. Internal discharges were generated in phase A, B and C of COP-B and pulv.-B, in phase B of Pulv. C and in phase C of Pulv.-D motor. Discharge at conductor surface was discovered in phase A of Pulv. D motor. Slot discharges occurred in three phases of Pulv. E motor.

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The Measurement and Analysis The Electromagnetic Wave by Discharge in Air for Insulation Diagnosis (절연진단을 위한 기중방전에서의 방사전자파 측정과 분석)

  • 이상훈;이현동;이춘하;윤영대;김기채;이광식;이동인
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1999.11a
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    • pp.141-144
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    • 1999
  • This paper offer fundamental ones about insulation diagnosis with electromagnetic wave, when discharges occurred. To simulate Partial-Discharge(PD), It is used needle-plane electrode in air. As the voltages applied, measure the electromagnetic wave with monopole antenna and analysis its fundamental characteristics, then, acquired data were operated. The results presented as the form of graph, and the magnitude of charge when occurred PD simultaneously. In conclusion, when the magnitude of charge over 100[pC], the electric field strength changed, and then the magnitude of charge and the electric field strength increased samely.

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Analysis of Partial Discharge in High Voltage Motor Model Coils (고압전동기 모델 코일의 부분방전 분석)

  • Kim, Hee-Dong;Kong, Tae-Sik
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2091-2093
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    • 2005
  • Five model coils of 6.6kV motor were manufactured with several defects. These stator coils have artificial defects such as void of groundwall insulation, removal of semi-conductive coating and damage of strand insulation. Epoxy-mica coupler(80 pF) was connected to five model coil terminals, respectively The voltage applied to the coils was 3.81kV, 4.76kV, 6.0kV and 6.6kV. Partial discharge(PD) tests performed in the laboratory and shield room. Digital PD detector (PDD) and turbine generator analyzer(TGA) were used to measure PD activity. TGA summarizes each plot with two quantities such as the normalized quantity number(NQN) and the peak PD magnitude(Qm). The PD levels in pC were measured with PDD. PD patterns of model coils were indicated the internal and slot discharges. PD patterns coincide with both PDD and TGA.

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