• Title/Summary/Keyword: insulation condition

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A Study on the Complex Accelerating Degradation and Condition Diagnosis of Traction Motor for Electric Railway (전기철도용 견인전동기의 복합가속열화 상태진단에 관한 연구)

  • 왕종배
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.1
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    • pp.93-101
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    • 2002
  • In this study, the stator form-winding sample coils based on silicone resin and polyimide were made for fault prediction and reliability estimation on the C-Class(200$\^{C}$ ) insulation system of traction motors. The complex accelerative degradation was periodically performed during 10 cycles, which was composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, the condition diagnosis test such as insulation resistance '||'&'||' polarization index, capacitance '||'&'||' dielectric loss and partial discharge properties were investigated in the temperature range of 20 ∼ 160$\^{C}$. Relationship among condition diagnosis tests was analyzed to find a dominative degradation factor and an insulation state at end-life point.

Analysis of Insulation Quality in Large Generator Stator Windings

  • Kim, Hee-Dong;Kong, Tae-Sik;Ju, Young-Ho;Kim, Byong-Han
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.384-390
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    • 2011
  • To evaluate the condition of stator winding insulation in generators that have been operated for a long period of time, diagnostic tests were performed on the stator bars of a 500 MW, 22 kV generator under accelerated thermal and electrical aging procedures. The tests included measurements of AC current (${\Delta}I$), dissipation factor ($tan{\delta}$), partial discharge (PD) magnitude, and capacitance (C). In addition, the AC current test was performed on the stator winding of a 350 MW, 24 kV generator under operation to confirm insulation deterioration. The values of ${\Delta}I$, ${\Delta}tan{\delta}$, and PD magnitude in one stator bar indicated serious insulation deterioration. In another stator bar, the ${\Delta}I$ measurements showed that the insulation was in good condition, whereas the values of ${\Delta}tan{\delta}$ and PD magnitude indicated an incipient stage of insulation deterioration. Measurements of ${\Delta}I$ and PD magnitude in all three phases (A, B, C) of the remaining generator stator windings showed that they were in good condition, although the ${\Delta}tan{\delta}$ measurements suggested that the condition of the insulation should be monitored carefully. Overall analysis of the results suggested that the generator stator windings were in good condition. The patterns of PD magnitude in all three phases (A, B, C) were attributed to internal discharge.

Change of Insulation Properties of Stator Coil fed by Inverter Source on Traction Motor (인버터 전원에 의한 견인전동기 고정자 코일의 절연특성 변화)

  • Jang, Dong-Uk;Park, Hyun-June;Lee, Gil-Hun;Choi, Jong-Sun;Lee, Jung-Soo
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.420-422
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    • 2003
  • Aging and failure of motor insulation depend on the stresses imposed on it. The insulation life time depends on the severity of the stresses. The electrical aging by transient surge is very important to traction motor in EMU(electric multiple unit). This paper Presents the insulation characteristics of stator coil by transient surge from inverter. There are several nondestructive tests available for checking the condition of motor insulation, the probable extent of aging,. and the rate of which aging is taking pace. So the insulation characteristics of stator coil were each analyzed by measurement of leakage current, dielectric loss($tan{\delta}$), capacitance, polarization index(PI) and partial discharge. The method of diagnosis is able to analyze the aging condition and Predict the life of the traction motor in EMU.

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Properties of Electrical Performance by Inverter Surge on Stator Coil of Traction Motor (인버터 서지에 의한 견인전동기 고정자 권선의 전기적 특성 변화)

  • Park, Hyun-June;Jang, Dong-Uk;Choi, Nam-Ho;Choi, Jong-Sun;Kim, Jung-Soo
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1285-1287
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    • 2003
  • The aging of the insulation reduces the electrical and mechanical strength of the insulation. At same point, a voltage surge or mechanical shock from a traction motor start will fracture or break down the insulation. To achieve the expected life usually requires extensive laboratory evaluation of the insulation systems and the use of accelerated aging tests. There are several nondestructive test available for checking. the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of dielectric loss($tan{\delta}$), capacitance and partial discharge. The method of diagnosis is able to analyze the aging condition and predict the life of the traction motor.

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A Study on the Condition Diagnosis for the Stator Coil of Traction Motor by Transient Surge (과도서지에 의한 견인전동기 고정자 코일의 상태진단 연구)

  • 박현준;장동욱;김길동;최종선;김정수
    • The Transactions of the Korean Institute of Power Electronics
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    • v.8 no.3
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    • pp.247-252
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    • 2003
  • Aging and failure of motor insulation depend on the stresses imposed on it. The insulation life time depends on the severity of the stresses. The electrical aging by transient surge is very important to traction motor in EMU(electric multiple unit). This paper presents the insulation characteristics of stator coil by transient surge from inverter. There are several nondestructive tests available for checking the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of leakage current, dielectric loss(tan $\delta$), capacitance, polarization index(PI) and partial discharge. The method of diagnosis is able to analyze the aging condition and predict the life of the traction motor in EMU.

Properties of Electrical Performance on Stator Coil of Traction Motor by Accelerated lest using Transient Surge (과도서지를 이용한 가속열화 시험법에 따른 견인전동기 고정자 코일의 전기적 특성 변화)

  • 박현준;장동욱;이길헌;최종선;김저우
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.9
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    • pp.783-789
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    • 2003
  • The winding problems of traction motor are the major determinant of motor's life. The root cause of winding failure is gradual deterioration of the insulation due to thermal, electrical, mechanical and environmental stresses. The aging of the insulation reduces the electrical and mechanical strength of the insulation. At same point, a voltage surge or mechanical shock from a traction motor start will fracture or break down the insulation. To achieve the expected life usually requires extensive laboratory evaluation of the insulation systems and the use of accelerated aging tests. There are several nondestructive test available for checking, the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of dielectric loss(tan$\sigma$), capacitance and partial discharge. The method of diagnosis is able to analyze the insulation condition and evaluate the life of the traction motor.

Site Evaluation and Application of the On-line and Off-line Test for the 13[kV] Class Hydropower Generator Stator Windings (13[kV]급 수력발전기 고정자 권선의 운전 및 정지 중 진단시험 현장적용 평가 및 분석)

  • Chang, Jeong-Ho;Lee, Dong-Keun;Lee, Heung-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.11
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    • pp.73-82
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    • 2011
  • The solid insulation system of stator windings in high voltage rotational machines is usually aging in accordance with long time operation. The partial discharge test have been known to check whether insulation deterioration exist or not, and the PD test can effectively diagnose a solid insulation condition regardless of during operation(on-line) or not(off-line). The on-line PD measurement have proven to be a successful technique in monitoring stator insulation condition nowadays. This paper describes the characteristics of comparing the on-line PD measurement data using PDMS-HG(Partial Discharge Monitoring System for Hydro-electric Generator) installed in field with the off-line diagnosis measurement data(insulation resistance, winding resistance, PI, ${\Delta}tan{\delta}$ and PD) on hydro generator(13[kV]) stator windings. These results make good use of managing rotational machines through evaluating the solid insulation condition of stator windings.

A Study on the Condition Diagnosis for A Gas-insulated Transformer using Decomposition Gas Analysis (가스분해 분석기법을 활용한 가스 전열 변압기의 상태 진단 연구)

  • Ah-Reum, Kim;Byeong Sub, Kwak;Tae-Hyun, Jun;Hyun-joo, Park
    • KEPCO Journal on Electric Power and Energy
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    • v.8 no.2
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    • pp.119-126
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    • 2022
  • A growing number of gas-insulated transformers in underground power substations in urban areas are approaching 20 years of operation, the time when failures begin to occur. It is thus essential to prevent failure through accurate condition diagnosis of the given facility. Various solid insulation materials exist inside of the transformers, and the generated decomposition gas may differ for each gas-insulated equipment. In this study, a simulation system was designed to analyze the deterioration characteristics of SF6 decomposition gas and insulation materials under the conditions of partial discharge and thermal fault for diagnosis of gas-insulated transformers. Degradation characteristics of the insulation materials was determined using an automatic viscometer and FT-IR. The analysis results showed that the pattern of decomposition gas generation under partial discharge and thermal fault was different. In particular, acetaldehyde was detected under a thermal fault in all types of insulation, but not under partial discharge or an arc condition. In addition, in the case of insulation materials, deterioration of the insulation itself rapidly progressed as the experimental temperature increased. It was confirmed that it was possible to diagnose the internal discharge or thermal fault occurrence of the transformer through the ratio and type of decomposition gas generated in the gas-insulated transformer.

Stator Insulation Quality Assessment for High Voltage Motors Based on Probability Distributions

  • Kim, Hee-Dong;Kim, Chung-Hyo
    • Journal of Electrical Engineering and Technology
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    • v.3 no.4
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    • pp.571-575
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    • 2008
  • Stator insulation quality assessment for high voltage motors is a major issue for the reliable maintenance of industrial and power plants. To assess the condition of stator insulation, nondestructive tests were performed on the sixty coil groups of twelve motors. After completing the nondestructive tests, the AC voltage applied to the stator winding was gradually increased until insulation failure in order to obtain the breakdown voltage. The stator winding of each motor was classified into five coil groups; one group with healthy insulation and four groups with four different types of artificial defects. To analyze the breakdown voltage statistically, Weibull distribution was employed for the tests on the fifty coil groups of ten motors. The 50th percentile values of the measured breakdown voltages based on the statistical data of the five coil groups of ten motors were 26.1kV, 25.0kV, 24.4kV, 26.7kV and 30.5kV, respectively. Almost all of the failures were located in the line-end coil at the exit of the core slot. The breakdown voltages and the types of defects showed strong relation to the stator insulation tests such as in the case of dissipation factor and ac current. It is shown that the condition of the motor insulation can be determined from the relationship between the probability of failure and the type of defect.

A Study on the Electrical Properties for the Insulation Design of a Conduction-Cooled HTS SMES (전도냉각 HTS SMES 절연설계를 위한 전기적 특성연구)

  • Choi, Jae-Hyeong;Kwag, Dong-Soon;Cheon, Hyeon-Gweon;Baek, Seung-Myeong;Kim, Hae-Jong;Seong, Ki-Chul;Kim, Sang-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.226-227
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    • 2006
  • The conduction-cooled HTS SMES is operated in cryogenic and high vacuum condition. Thus, Insulation design at cryogenic temperature and high vacuum is a key and an important element that should be established to accomplish miniaturization that is a big advantage of HTS SMES. Therefore, we need active research and development of insulation concerning application of the conduction-cooled HTS SMES. Therefore, in this study, we experimented about insulation characteristic high vacuum and cryogenic similar to driving condition of SMES system. Also, investigated about insulation characteristic of suitable some materials to insulator for conduction-cooled HTS SMES. As this results, we possessed basis data for insulation materials selection and insulation design for development of 600 kJ class conduction-cooled HTS SMES.

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