Measurement variations of insulation resistance/polarization index during utilizing time in HV electrical machines – A survey

Torkaman, Hossein; Karimi, F.

doi:10.1016/j.measurement.2014.09.034

Cited by 35 publications

(16 citation statements)

References 56 publications

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“…Karakteristik nilai IR dan PI pada isolasi yang dipengaruhi oleh tekanan telah diteliti [4], [10]˗ [11]. Secara umum, karakteristik kedua nilai tersebut akan bergantung pada jenis tekanan dan tingkat degradasi isolasi.…”

Section: Issn 2301 -4156unclassified

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Evaluasi Degradasi Isolasi Motor akibat Multi-factor Aging berdasarkan Indeks Polarisasi dan SEM-EDX

Wahyudi¹,

Asfani²,

Negara³

et al. 2019

Jurnal Nasional Teknik Elektro dan Teknologi Informasi

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The operation of induction motor affected by stress factor causes insulation degradation. This degradation can be observed from changes in insulation characteristics, including electrical, physical, and chemical. This study aimed to evaluate the insulation resistance (IR) and polarization index (PI) since the induction motor condition was good until burned out. Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX) testing was also carried out to analyze changes in microstructure, morphological characteristics, and chemical composition in stator windings. In addition, X-ray powder diffraction (XRD) testing was presented to validate that the damaged insulation was caused by the given stress. To accelerate degradation of insulation, induction motor in service condition was subjected by a lot of pressure simultaneously, including thermal, moisture, and salt contamination. The accelerated aging testing was gradually conducted according to three schemes with different pressure levels. The results showed that the applied stresses could accelerate the insulation aging. A significant decrease of IR and PI values was found in the third scheme, as the IR value was less than 5 MΩ and the PI value was 0.6 (danger category). The insulation failure was achieved at a total duration of testing for 222 hours. The results of SEM-EDX and XRD testing showed the presence of mineral deposits from water vapor, salt contaminants, cracks, and fracture on the insulation surface. Intisari-Pengoperasian motor induksi yang dipengaruhi oleh faktor tekanan dapat menyebabkan degradasi isolasi. Degradasi tersebut dapat diamati dari perubahan karakteristik isolasi, meliputi elektris, fisik, dan kimiawi. Makalah ini bertujuan untuk mengevaluasi nilai tahanan isolasi dan indeks polarisasi sejak kondisi motor induksi baik hingga rusak. Pengujian SEM-EDX juga dilakukan untuk menganalisis perubahan mikrostruktur, karakteristik morfologi, dan komposisi kimia pada isolasi belitan motor. Di samping itu, pengujian XRD dilakukan untuk memvalidasi bahwa kerusakan isolasi disebabkan oleh tekanan yang diberikan. Untuk mempercepat degradasi isolasi, motor induksi dalam kondisi beroperasi diberikan banyak tekanan secara simultan, meliputi termal (karena beban lebih), kelembapan, dan kontaminasi garam (sebagai partikel konduktif). Pengujian dilakukan secara bertahap menurut tiga skema dengan tingkat tekanan yang berbeda-beda. Hasil menunjukkan bahwa pemberian tekanan secara simultan mampu mempercepat umur isolasi. Penurunan nilai IR dan PI yang signifikan ditemui pada pengujian skema 3, sebagaimana nilai IR kurang dari 5 MΩ dan nilai PI sebesar 0,6 (kategori berbahaya). Kegagalan isolasi tercapai pada total durasi pengujian selama 222 jam. Hasil pengujian SEM-EDX dan XRD menunjukkan adanya endapan mineral dari uap air, kontaminan garam, retakan, dan patahan pada permukaan isolasi. Kata Kunci-Indeks polarisasi (PI), degradasi isolasi motor, SEM-EDX, tahanan isolasi (IR), XRD.

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Section: Issn 2301 -4156unclassified

“…Berbeda dengan [4], [9]˗ [11], [15], pemberian banyak tekanan pada makalah ini dilakukan secara simultan dan motor induksi dalam kondisi beroperasi dan berbeban. Skema pengujian tersebut akan lebih menyerupai kondisi riil di lapangan.…”

Section: Issn 2301 -4156unclassified

Evaluasi Degradasi Isolasi Motor akibat Multi-factor Aging berdasarkan Indeks Polarisasi dan SEM-EDX

Wahyudi¹,

Asfani²,

Negara³

et al. 2019

Jurnal Nasional Teknik Elektro dan Teknologi Informasi

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“…FDS has been successfully used for power transformer insulation assessment [5,6]. In recent years, there has been growing interest in insulation diagnostics of epoxy-mica insulation using non-invasive techniques [7][8][9][10][11][12]. However, clear identification of ageing sensitive parameters remains a challenge.…”

Section: Introductionmentioning

confidence: 99%

Method for identifying ageing in epoxy‐mica composite insulation used in rotational machines through modelling of dielectric relaxation

et al. 2020

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Dielectric response analysis, performed in time domain and frequency domain is one of the interesting methods used for condition assessment of high voltage equipment. In this article, the degradation of epoxy-mica composite insulation which is widely used in rotating machines has been investigated through frequency domain spectroscopy measurements. Artificial ageing of the carefully prepared stator bar insulation sample was performed through simultaneous application of high temperature and electric field in a designated environmental chamber for specific durations. To study the effect of temperature, the measurements were performed at temperatures ranging from 20 to 60°C at different ageing status. Following experimental work, the measurement results were modelled using Havriliak-Negami model and ageing sensitive parameters were extracted. To study the effect of temperature, the measurements were performed at temperatures ranging from 20 to 60°C. The modelled results matched well with the experimental measurements and certain model parameters sensitive to the ageing condition were identified. The numerical relationships between the insulation status of the stator bar and the aforementioned parameters were identified. It was observed that the nature of the numerical relationship remains identical in the investigated temperature range, although the coefficients vary to some extent.

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“…In the case of mechanical failures, predictive procedures based on vibration analysis are well developed and widely accepted [6][7][8][9][10][11]. For electrical problems, the most common preventive techniques are: (i) measurement of the insulation resistance R I between windings and ground, and calculation of the polarisation index (PI) and absorption index (AI) [12][13][14][15]; (ii) spectral analysis of the stator current, also known as electrical signature analysis [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]; and (iii) partial discharge analysis (PDA) [32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Insulation protection and online stress agent identification for electric machines using artificial intelligence

Guedes

Silva²

2019

IET Electric Power Applications

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Insulation failures are among the most important problems affecting electric machines. Although standard procedures are widely used to assess the insulation condition of these machines, no alternative is available to allow the identification of the stress agents affecting the insulation system. Another limitation of the standard procedures is the fact that they are based on tests that require the interruption of the operation of the machine. This study presents a technique that allows the online assessment and protection of the insulation of low-and medium-voltage electric machines, along with the identification of the stress agents responsible for the degradation of the insulation. The proposed technique is based on the use of a highly sensitive current transformer, an algorithm to identify the most affected phase, and an artificial neural network to indicate the stress agent affecting the machine. The presented experimental results show that the proposed system can identify thermal degradation, moisture absorption and contamination by oil. The low current levels that can be measured by the developed system enable the application of the proposed technique to low-and medium-voltage machines.

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Measurement variations of insulation resistance/polarization index during utilizing time in HV electrical machines – A survey

Cited by 35 publications

References 56 publications

Evaluasi Degradasi Isolasi Motor akibat Multi-factor Aging berdasarkan Indeks Polarisasi dan SEM-EDX

Evaluasi Degradasi Isolasi Motor akibat Multi-factor Aging berdasarkan Indeks Polarisasi dan SEM-EDX

Method for identifying ageing in epoxy‐mica composite insulation used in rotational machines through modelling of dielectric relaxation

Insulation protection and online stress agent identification for electric machines using artificial intelligence

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