• Title, Summary, Keyword: Partial discharge

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The measurement of partial discharge for preventive diagnosis in power machinery (전력용 기기의 예방진단을 위한 부분방전측정)

  • 김태성;구할본;임장섭;정우성
    • Electrical & Electronic Materials
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    • v.7 no.1
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    • pp.42-48
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    • 1994
  • The preventive diagnosis technique for power system is being highlighted as a research area for deterioration of insulation in machinery because of high-voltage power system. We make efforts to develop not only diagnosis of aging state but also detection of defects in the initial stage from preventive diagnosis technique. Especially, partial discharge is actively studied as a non-destructive diagnosis technique and very useful because partial discharge measurement reduces damage than conventional diagnosis technique. The loaded stress during this test is smaller than that of other diagnosis techniques. But the continuous research for various complicated analysis method is required because partial discharge has very small signals and its signals have complex forms. In this paper, the measurement of partial discharge was investigated and studied on many specimens with void. We made samples having artificial voids and measured partial discharge. In order to use as a practical diagnosis technique, we studied ways of measurement, measured illustrations and types of partial discharge which could be used in order to diagnose defects of power machinery.

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Characteristics of Ultra High Frequency Partial Discharge Signals from Metallic Particle Defected Oil-paper Insulation in Transformer (변압기 절연지 표면 금속 이물질 방전에 의한 극초단파 신호특성)

  • Yoon, Jin-Yul;Ju, Hyung-Jun;Goo, Sun-Geun;Park, Ki-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.10
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    • pp.879-883
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    • 2009
  • This paper was provided to help in detecting defects in power transformer. For this purpose, a partial discharge cell was designed and manufactured as a discharge source to simulate particle defected paper-oil insulation in power transformer. Experimental set-up for measuring PD signals was described. 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 pattern of PRPD(Phase Resolved Partial Discharge) of partial discharge signals were examined and analyzed. The results will be contributed to build the defect database of power transformer and to decrease the substation faults.

Off-Line and On-Line Partial Discharge Properties of Large Turbine Generator (대용량 터빈발전기 고정자 권선의 정지중 및 운전중 부분방전 특성)

  • Kim, Hee-Dong;Lee, Young-Jun
    • Proceedings of the KIEE Conference
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    • pp.1846-1849
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    • 2000
  • Off-line and on-line partial discharges were measured on a 828MVA, 22kV and direct hydrogen-cooled large turbine generator. Partial discharge tests were conducted using digital partial discharge detector(PDD) and turbine generator analyzer(TGA). PDD and TGA showed that off-line partial discharge pattern seems to be very, similar to that found with on-line. Most of the partial discharge is originating with the stator slot in the three phases. As the partial discharge activity is very low, the stator insulation condition of this generator is very good.

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Partial Discharge Detection of High Voltage Switchgear Using a Ultra High Frequency Sensor

  • Shin, Jong-Yeol;Lee, Young-Sang;Hong, Jin-Woong
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.4
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    • pp.211-215
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    • 2013
  • Partial discharge diagnosis techniques using ultra high frequencies do not affect load movement, because there is no interruption of power. Consequently, these techniques are popular among the prevention diagnosis methods. For the first time, this measurement technique has been applied to the GIS, and has been tested by applying an extra high voltage switchboard. This particular technique makes it easy to measure in the live state, and is not affected by the noise generated by analyzing the causes of faults ? thereby making risk analysis possible. It is reported that the analysis data and the evaluation of the risk level are improved, especially for poor location, and that the measurement of Ultra high frequency (UHF) partial discharge of the real live wire in industrial switchgear is spectacular. Partial discharge diagnosis techniques by using the Ultra High Frequency sensor have been recently highlighted, and it is verified by applying them to the GIS. This has become one of the new and various power equipment techniques. Diagnosis using a UHF sensor is easy to measure, and waveform analysis is already standardized, due to numerous past case experiments. This technique is currently active in research and development, and commercialization is becoming a reality. Another aspect of this technique is that it can determine the occurrences and types of partial discharge, by the application diagnosis for live wire of ultra high voltage switchgear. Measured data by using the UHF partial discharge techniques for ultra high voltage switchgear was obtained from 200 places in Gumi, Yeosu, Taiwan and China's semiconductor plants, and also the partial discharge signals at 15 other places were found. It was confirmed that the partial discharge signal was destroyed by improving the work of junction bolt tightening check, and the cable head reinforcement insulation at 8 places with a possibility for preventing the interruption of service. Also, it was confirmed that the UHF partial discharge measurement techniques are also a prevention diagnosis method in actual industrial sites. The measured field data and the usage of the research for risk assessment techniques of the live wire status of power equipment make a valuable database for future improvements.

A Study on Three Phase Partial Discharge Pattern Classification with the Aid of Optimized Polynomial Radial Basis Function Neural Networks (최적화된 pRBF 뉴럴 네트워크에 이용한 삼상 부분방전 패턴분류에 관한 연구)

  • Oh, Sung-Kwun;Kim, Hyun-Ki;Kim, Jung-Tae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.4
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    • pp.544-553
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    • 2013
  • In this paper, we propose the pattern classifier of Radial Basis Function Neural Networks(RBFNNs) for diagnosis of 3-phase partial discharge. Conventional methods map the partial discharge/noise data on 3-PARD map, and decide whether the partial discharge occurs or not from 3-phase or neutral point. However, it is decided based on his own subjective knowledge of skilled experter. In order to solve these problems, the mapping of data as well as the classification of phases are considered by using the general 3-PARD map and PA method, and the identification of phases occurring partial discharge/noise discharge is done. In the sequel, the type of partial discharge occurring on arbitrary random phase is classified and identified by fuzzy clustering-based polynomial Radial Basis Function Neural Networks(RBFNN) classifier. And by identifying the learning rate, momentum coefficient, and fuzzification coefficient of FCM fuzzy clustering with the aid of PSO algorithm, the RBFNN classifier is optimized. The virtual simulated data and the experimental data acquired from practical field are used for performance estimation of 3-phase partial discharge pattern classifier.

Detection and localization of partial discharge in high-voltage direct current cables using a high-frequency current transformer (HFCT를 활용한 고전압직류송전 케이블 부분방전 위치추정)

  • Hong, Seonmin;Son, Wooyoung;Cheon, Hyewon;Kang, Daekyoung;Park, Jonghoo
    • Journal of Sensor Science and Technology
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    • v.30 no.2
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    • pp.105-108
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    • 2021
  • Detection and localization of partial discharge are considered critical techniques for estimating the lifetimes of power cables. High-frequency current transformers (HFCTs) are commonly used for the detection of partial discharge in high-voltage alternating current (HVAC) power cables; however, their applicability is compromised by the limitations of the installation locations. HFCTs are typically installed in cable terminals or insulation joint boxes because HVACs induce strong time-varying magnetic fields around the cables, saturating the ferromagnetic materials in the HFCTs. Therefore, partial discharges near the installation locations can be detected. In this study, the feasibility of partial discharge detection using a HFCT was investigated for high-voltage direct current (HVDC) cables. We demonstrated that the HFCT could be installed at any location in the HVDC power cable to monitor partial discharge along the entire cable length. Furthermore, we showed that the HFCT could detect the location of partial discharge with high accuracy.

UHF Sensor Location Optimization for Partial Discharge Signals Detection Method (UHF 센서 위치 최적화로 부분방전 신호 검출 방법)

  • Choi, Mun-Gyu;Cha, Hanju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.3
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    • pp.409-413
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    • 2014
  • GIS partial discharge that occurred in the UHF band signal is effectively detected by the method to IEC60270 5pc the apparent minimum discharge can be detected over the GIS arrangement of the sensor interior and exterior of the UHF in accordance with the optimized position signal by considering the damping ratio is selected so that the signals can be obtained to be mounted. 362kV, 800kV GIS is installed on the internal and external sensors are UHF band signal attenuation is set by measuring the reference value, but the operation, 170kV case 362kV, 800kV on the basis of the measurement data and to be installed and operated. When 170kV per 1Bay by installing the built-in sensor 1 for detecting a partial discharge signal, But, GIS signal attenuation is large in the case of an internal partial discharge signal is not detected in some cases. Where the attenuation is great UHF signal of the sensor by increasing the quantity of partial discharge signals were acquired to allow relocation. The greater the spacing between the sensor and the sensor is applied simplifies the installation and reduces the cost in terms of maintenance of appropriate optimal position is calculated to detect the partial discharge signal is needed. Thus 170kV GIS signal power attenuation of a partial discharge by measuring the UHF sensor, and by relocating the proper position is calculated in accordance with the sensor signal decay rate and minimize the error of omission in detecting a partial discharge signal was optimized.

Partial Discharge Property of Hydrogenerator Stator Windings (수력발전기 고정자 권선에서 부분방전 특성)

  • Kim, Hee-Dong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.86-90
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    • 2000
  • Partial discharge(PD) tests were performed when the hydrogenerator(rated 11kV and 25MVA) was shut down(off-line). Six cable couplers were installed in the ring bus as well as within hydrogenerator terminal box. PD tests were conducted using partial discharge analyzer(PDA) and digital partial discharge detector(PDD). PDA showed that the normalized quantity number(NQN) and the partial discharge magnitude increased with increase of ac voltage. Slot discharges were discovered in three phases(A, B and C) at the rated voltage. PDA and PDD test results are in accordance with the pattern and magnitude of partial discharge. This hydrogenerator stator windings were in good condition.

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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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    • 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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The Effect of Pressurized Hydrogen on the Aging and Partial Discharge Activity in Generator Winding Insulations (가압 수소가 발전기 고정자 권선 절연 열화와 부분 방전 특성에 미치는 영향)

  • 김진봉
    • Journal of the Korean Society of Safety
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    • v.14 no.4
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    • pp.100-107
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    • 1999
  • The purpose of the study is to investigate the effect of H$_2$ pressure on partial discharge (PD) activity and aging rate in turbine generator winding insulations. A series of field tests and laboratory tests were peformed to investigate the effect of $H_2$ pressure on PD activity. Field tests were conducted at two unit turbine generators in two conditions, in $H_2$ pressure and in air atmosphere. Obtained results are as follows ; 1) ${\Delta}tan{\delta}$ and maximum partial discharge are reduced with increase of $H_2$ pressure and partial discharge inception voltage. 2) The reduction ratio of ${\Delta}tan{\delta}$ due to $H_2$ pressure is higher than one of PD magnitude. 3) Partial discharge pulses suffer from attenuation and distortion when transmitted along windings, because of the complex L-C network between windings. From the result, partial discharge pulses are subjected to resonance phenomena in a generator winding.

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