Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464453
R. Bozzo, G. Calci, P. Girdinio, P. Molfino, G. Molinari, A. Viviani
A model of impurity particle motion in a dielectric fluid under the action of an electric field, previously developed by some of the authors, is presented with the improvements suggested by both a larger amount of experimental data and the need of application to practical field configurations. A system for both computer-aided analysis of data obtained from high speed movie and electrical measurements about impurity particle motion and theoretical simulation of the phenomenon is presented, and some obtained results are displayed and discussed.
{"title":"A system for computer-aided theoretical and experimental analysis of impurity particle motion in dielectric liquids","authors":"R. Bozzo, G. Calci, P. Girdinio, P. Molfino, G. Molinari, A. Viviani","doi":"10.1109/EIC.1982.7464453","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464453","url":null,"abstract":"A model of impurity particle motion in a dielectric fluid under the action of an electric field, previously developed by some of the authors, is presented with the improvements suggested by both a larger amount of experimental data and the need of application to practical field configurations. A system for both computer-aided analysis of data obtained from high speed movie and electrical measurements about impurity particle motion and theoretical simulation of the phenomenon is presented, and some obtained results are displayed and discussed.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"7 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126847485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464490
A. Bulinski, S. Bamji, J. Densley
The main points of the study reported in this paper are as follows: (i) The amount of moisture in XLPE does not affect the short term ac breakdown strength, provided the insulation is not subjected to electrical stress prior to the breakdown test. (ii) Preimmersing XLPE insulation in tap water prior to electrical aging at room temperature results in a reduction of more than 50% in the breakdown voltage. The preimmersion increases the moisture content, particularly liquid water at room temperature, resulting in increased degradation. (iii) Preimmersion does not have any effect on the breakdown voltage of cables electrically aged at 70°C or 90°C. (iv) For some aging conditions, the short term breakdown voltages of aged cables give no indication of the number of and times to breakdown of the cables during the electrical aging. (v) Direct voltage is quite sensitive to degradation of XLPE by the combined action of moisture and electric stress. Care must be exercised when dc testing aged cables in service. (vi) Complete drying of cables aged in water restores the breakdown voltage to its original value. The improvement is, however, only temporary and the breakdown voltage decreases at a faster rate when aging is continued. (vii) Temperature cycling of the insulation causes small changes in the short term ac breakdown voltage. However, the number of breakdowns occurring during the initial aging (1000 h) is much larger for the temperature cycled cable, indicating that temperature cycling could be an important variable in an accelerated aging test. Whether there is an optimum temperature change to produce maximum degradation still remains to be determined.
{"title":"The effects of moisture content, frequency and temperature on the life of miniature XLPE cables","authors":"A. Bulinski, S. Bamji, J. Densley","doi":"10.1109/EIC.1982.7464490","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464490","url":null,"abstract":"The main points of the study reported in this paper are as follows: (i) The amount of moisture in XLPE does not affect the short term ac breakdown strength, provided the insulation is not subjected to electrical stress prior to the breakdown test. (ii) Preimmersing XLPE insulation in tap water prior to electrical aging at room temperature results in a reduction of more than 50% in the breakdown voltage. The preimmersion increases the moisture content, particularly liquid water at room temperature, resulting in increased degradation. (iii) Preimmersion does not have any effect on the breakdown voltage of cables electrically aged at 70°C or 90°C. (iv) For some aging conditions, the short term breakdown voltages of aged cables give no indication of the number of and times to breakdown of the cables during the electrical aging. (v) Direct voltage is quite sensitive to degradation of XLPE by the combined action of moisture and electric stress. Care must be exercised when dc testing aged cables in service. (vi) Complete drying of cables aged in water restores the breakdown voltage to its original value. The improvement is, however, only temporary and the breakdown voltage decreases at a faster rate when aging is continued. (vii) Temperature cycling of the insulation causes small changes in the short term ac breakdown voltage. However, the number of breakdowns occurring during the initial aging (1000 h) is much larger for the temperature cycled cable, indicating that temperature cycling could be an important variable in an accelerated aging test. Whether there is an optimum temperature change to produce maximum degradation still remains to be determined.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121166881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464439
W. K. Hogg, R. Miller, G. Rabach, D. Ryder
The methods of analysing the various individual partial discharge patterns using discriminating pulse amplitude techniques, in particular a multi-channel analyser (MCA) with several hundred pre-selected amplitude gates/channels, is in many instances a powerful method for assessing the relative quality of electrical insulating materials and systems to discharge attack.
{"title":"The relationship of partial discharge amplitude distributions with dielectric damage at different levels of voltage and frequency","authors":"W. K. Hogg, R. Miller, G. Rabach, D. Ryder","doi":"10.1109/EIC.1982.7464439","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464439","url":null,"abstract":"The methods of analysing the various individual partial discharge patterns using discriminating pulse amplitude techniques, in particular a multi-channel analyser (MCA) with several hundred pre-selected amplitude gates/channels, is in many instances a powerful method for assessing the relative quality of electrical insulating materials and systems to discharge attack.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"241 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133934943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464450
C. Venkataseshaiah, C. N. Reddy, T. Eish
The results of experimental investigations on anomalous breakdown in polymethylmethacrylate (PMMA) immersed in transformer oil and subjected to switching surge voltages superimposed on direct voltage are reported in this paper. The anomalous breakdown voltage under such combined stresses was found to be much lower than that under direct voltage stresses alone. It is also affected by the relative polarities of the two voltages: When they are same, it increases considerably with increase in direct prestressing voltage; when they are opposite, it decreases a little. The polarity of the resultant applied voltage was also found to have effect on the distance of the anomalous breakdown location from the h.v. electrode. The duration of the superimposed switching surge (1.2/50 µs to 1000/10000 µs) also was found to affect the anomalous breakdown volt age. An attempt is made to explain such anomalous behaviour in modern solid synthetic insulating materials.
{"title":"Anomalous breakdown in PMMA under switching surges superimposed on direct voltage","authors":"C. Venkataseshaiah, C. N. Reddy, T. Eish","doi":"10.1109/EIC.1982.7464450","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464450","url":null,"abstract":"The results of experimental investigations on anomalous breakdown in polymethylmethacrylate (PMMA) immersed in transformer oil and subjected to switching surge voltages superimposed on direct voltage are reported in this paper. The anomalous breakdown voltage under such combined stresses was found to be much lower than that under direct voltage stresses alone. It is also affected by the relative polarities of the two voltages: When they are same, it increases considerably with increase in direct prestressing voltage; when they are opposite, it decreases a little. The polarity of the resultant applied voltage was also found to have effect on the distance of the anomalous breakdown location from the h.v. electrode. The duration of the superimposed switching surge (1.2/50 µs to 1000/10000 µs) also was found to affect the anomalous breakdown volt age. An attempt is made to explain such anomalous behaviour in modern solid synthetic insulating materials.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131670754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464465
A. Hossam-eldin, A. M. Khalil
This paper reports recent investigations into the breakdown strength of oil-impregnated paper-lapped transformer conductors using three types of paper, namely, paper containing manila, crepe-paper and paper with controlled extension. The effect of paper characteristics, such as thickness, air impermeability and density on the insulating surge and alternating electric strength is investigated.
{"title":"Insulation strength and breakdown of impregnate D paper-lapped conductors for transformers","authors":"A. Hossam-eldin, A. M. Khalil","doi":"10.1109/EIC.1982.7464465","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464465","url":null,"abstract":"This paper reports recent investigations into the breakdown strength of oil-impregnated paper-lapped transformer conductors using three types of paper, namely, paper containing manila, crepe-paper and paper with controlled extension. The effect of paper characteristics, such as thickness, air impermeability and density on the insulating surge and alternating electric strength is investigated.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116997622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464469
E. Gockenbach, J. Meppelink
The breakdown behaviour of model arrangements (rod to plane, sphere to plane) and natural size arrangements (ring to rod, coaxial cylinders) was studied using oscillating lightning impulse voltage and lightning impulse voltage in air and SF6. Using a simplified equivalent circuit, the voltage curve and the values of the circuit elements can be calculated. At the model arrangement as well as at a natural size arrangement breakdowns in air occured below the impulse withstand voltage Ud0 at both polarities in SF6 only by negative polarity at the natural size arrangement.
{"title":"Breakdown behaviour of nonuniform arrangements in air and SF6 using oscillating lightning impulse voltage","authors":"E. Gockenbach, J. Meppelink","doi":"10.1109/EIC.1982.7464469","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464469","url":null,"abstract":"The breakdown behaviour of model arrangements (rod to plane, sphere to plane) and natural size arrangements (ring to rod, coaxial cylinders) was studied using oscillating lightning impulse voltage and lightning impulse voltage in air and SF6. Using a simplified equivalent circuit, the voltage curve and the values of the circuit elements can be calculated. At the model arrangement as well as at a natural size arrangement breakdowns in air occured below the impulse withstand voltage Ud0 at both polarities in SF6 only by negative polarity at the natural size arrangement.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117191189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464462
Y. Abed
The present work reports an experimental investigation of the effect of temperature rise on the leakage current and thermal breakdown in power cables under both A. C. and D. C. high voltages. An empirical equation was found to give the relation between the leakage current and the temperature of the insulation. It was observed that the thermal breakdown occurs when the heat generation in the insulation is larger than the heat dissipation in the surrounding soil. The variation of the leakage current with the temperature was well investigated and it was found that the leakage current increases with the increasing of insulation temperature. Leakage current in power cable predicts the critical breakdown voltage of the cable. It was anticipated that a significant of deterioration could be detected by measuring the leakage current at the operating temperature especially if the deterioration had progressed to a point where the cable failure is imminent.
{"title":"Effect of temperature rise on leakage current and breakdown of power cables","authors":"Y. Abed","doi":"10.1109/EIC.1982.7464462","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464462","url":null,"abstract":"The present work reports an experimental investigation of the effect of temperature rise on the leakage current and thermal breakdown in power cables under both A. C. and D. C. high voltages. An empirical equation was found to give the relation between the leakage current and the temperature of the insulation. It was observed that the thermal breakdown occurs when the heat generation in the insulation is larger than the heat dissipation in the surrounding soil. The variation of the leakage current with the temperature was well investigated and it was found that the leakage current increases with the increasing of insulation temperature. Leakage current in power cable predicts the critical breakdown voltage of the cable. It was anticipated that a significant of deterioration could be detected by measuring the leakage current at the operating temperature especially if the deterioration had progressed to a point where the cable failure is imminent.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122722441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464496
N. Shimizu, J. Mori, M. Kosaki, K. Horii
This paper describes the effect of the oxygen absorbed in the free volume of polyethylene on electrical treeing phenomena. The ac tree initiation and growth were investigated at room temperature using virgin samples and also samples degassed by a vacuum pump. The tree starting voltage of the degassed samples is much higher than that of virgin samples. The experimental results show this improvement can be attributed to the removal of oxygen from PE. We also observed in detail the processes of tree initiation and growth in the degassed samples. The observations with other results led us to conclude that the charge carriers injected from the point electrode play a dominant role in the tree initiation.
{"title":"The effect of absorbed oxygen on electrical treeing in polymers","authors":"N. Shimizu, J. Mori, M. Kosaki, K. Horii","doi":"10.1109/EIC.1982.7464496","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464496","url":null,"abstract":"This paper describes the effect of the oxygen absorbed in the free volume of polyethylene on electrical treeing phenomena. The ac tree initiation and growth were investigated at room temperature using virgin samples and also samples degassed by a vacuum pump. The tree starting voltage of the degassed samples is much higher than that of virgin samples. The experimental results show this improvement can be attributed to the removal of oxygen from PE. We also observed in detail the processes of tree initiation and growth in the degassed samples. The observations with other results led us to conclude that the charge carriers injected from the point electrode play a dominant role in the tree initiation.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"232 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134041502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464491
S. Grzybowski, E. Robles, O. Dorlanne
The paper describes the morphological structure in different parts of XLPE high voltage cables. High voltage cable specimens were tested before and after thermal ageing using a scanning electron microscope. It was found that the morphological structure of the tested samples was variable in different parts of the cable and the morphology was becoming less crystalline farther from the cable conductor. The thermal ageing reduces the formation of the crystallinity of the cable insulation.
{"title":"The morphological structure in different parts of XLPE high voltage cables","authors":"S. Grzybowski, E. Robles, O. Dorlanne","doi":"10.1109/EIC.1982.7464491","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464491","url":null,"abstract":"The paper describes the morphological structure in different parts of XLPE high voltage cables. High voltage cable specimens were tested before and after thermal ageing using a scanning electron microscope. It was found that the morphological structure of the tested samples was variable in different parts of the cable and the morphology was becoming less crystalline farther from the cable conductor. The thermal ageing reduces the formation of the crystallinity of the cable insulation.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132430836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-06-07DOI: 10.1109/EIC.1982.7464471
C. Cooke
An Investigation of electrode surface effects has indicated that surface defects are a major cause of non-ideal performance of large gaps used in SF6 gas. A discharge inception model with a sensitivity analysis demonstrates that realistic size surface irregularities can initiate failures that compare well with test measurements. Also, a method to treat area effects by using surface statistics has been demonstrated.
{"title":"Electrode surface effects on large gap breakdown in SF6 gas","authors":"C. Cooke","doi":"10.1109/EIC.1982.7464471","DOIUrl":"https://doi.org/10.1109/EIC.1982.7464471","url":null,"abstract":"An Investigation of electrode surface effects has indicated that surface defects are a major cause of non-ideal performance of large gaps used in SF6 gas. A discharge inception model with a sensitivity analysis demonstrates that realistic size surface irregularities can initiate failures that compare well with test measurements. Also, a method to treat area effects by using surface statistics has been demonstrated.","PeriodicalId":422317,"journal":{"name":"1982 IEEE International Conference on Electrical Insulation","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116789207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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