Pub Date : 2002-04-07DOI: 10.1109/ELINSL.2002.995989
F. Berton, R. Patsch
Pulse sequence analysis is a powerful tool to characterize defects that generate partial discharges. Usually, frequency distributions or scatter plots of sequence correlated parameters such as e.g. the external voltage differences /spl Delta/U between consecutive discharge events are used for diagnosis. In some cases, the analysis of the times of occurrence and especially the sequence of time-intervals /spl Delta/t between consecutive discharge pulses may even be more efficient to characterize a defect or to differentiate between different defects. In the case of only a few discharge events per cycle of the applied voltage, the parameter /spl Delta/U is very efficient and allows to distinguish clearly whether the partial discharge signals are generated by only one or more local defects, information that is very helpful for a reliable diagnosis. Even with only one type of defect, a small change in the height of the measuring voltage may significantly influence the discharge phenomenon, resp. the measured date set. The analysis of the frequency distributions of the time differences /spl Delta/t of consecutive discharge events and the elimination of 'multiple discharge pulses' together with the use of the parameter /spl Delta/U//spl Delta/t reveal very useful additional information.
{"title":"The use of time intervals between consecutive discharges to characterize PD-sources","authors":"F. Berton, R. Patsch","doi":"10.1109/ELINSL.2002.995989","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995989","url":null,"abstract":"Pulse sequence analysis is a powerful tool to characterize defects that generate partial discharges. Usually, frequency distributions or scatter plots of sequence correlated parameters such as e.g. the external voltage differences /spl Delta/U between consecutive discharge events are used for diagnosis. In some cases, the analysis of the times of occurrence and especially the sequence of time-intervals /spl Delta/t between consecutive discharge pulses may even be more efficient to characterize a defect or to differentiate between different defects. In the case of only a few discharge events per cycle of the applied voltage, the parameter /spl Delta/U is very efficient and allows to distinguish clearly whether the partial discharge signals are generated by only one or more local defects, information that is very helpful for a reliable diagnosis. Even with only one type of defect, a small change in the height of the measuring voltage may significantly influence the discharge phenomenon, resp. the measured date set. The analysis of the frequency distributions of the time differences /spl Delta/t of consecutive discharge events and the elimination of 'multiple discharge pulses' together with the use of the parameter /spl Delta/U//spl Delta/t reveal very useful additional information.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"63 1","pages":"527-530"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83072476","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995899
M. Judd, G. P. Cleary, C. J. Bennoch, J. Pearson, T. Breckenridge
Sensors operating in the ultra-high frequency (UHF) band have been used to detect internal discharges during site testing of a 1000 MVA oil-filled transformer. The transformer was operated at voltages exceeding normal levels by up to 15%. Two discharge sources were detected at both sensors using UHF test equipment. Discharge signals are analyzed in phase-resolved form and time-of-flight measurements are used to provide further information regarding their origin. The results indicate that the UHF method could prove very effective for transformer testing and online PD monitoring.
{"title":"Power transformer monitoring using UHF sensors: site trials","authors":"M. Judd, G. P. Cleary, C. J. Bennoch, J. Pearson, T. Breckenridge","doi":"10.1109/ELINSL.2002.995899","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995899","url":null,"abstract":"Sensors operating in the ultra-high frequency (UHF) band have been used to detect internal discharges during site testing of a 1000 MVA oil-filled transformer. The transformer was operated at voltages exceeding normal levels by up to 15%. Two discharge sources were detected at both sensors using UHF test equipment. Discharge signals are analyzed in phase-resolved form and time-of-flight measurements are used to provide further information regarding their origin. The results indicate that the UHF method could prove very effective for transformer testing and online PD monitoring.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"390 1","pages":"145-149"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80536058","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.996005
G. Stone, V. Warren, M. Fenger
Online partial discharge testing has long been used to assess the condition of the high-voltage insulation in motor and generator stator windings. Past research has shown that motor and generator operating parameters such as voltage, power output, gas pressure, and stator winding temperature can have an important impact on the PD levels, and thus must be controlled if useful trends in PD activity over time are to be obtained. Over the years, results have been collected that indicate humidity may also be a factor that needs to be monitored. In addition, some simple laboratory experiments have been performed to verify that humidity can change the PD. When applying online PD testing to assess stator winding insulation condition, users must be aware of the influence of humidity on the measured PD activity to properly interpret the results.
{"title":"Case studies on the effect of humidity on stator winding partial discharge activity","authors":"G. Stone, V. Warren, M. Fenger","doi":"10.1109/ELINSL.2002.996005","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.996005","url":null,"abstract":"Online partial discharge testing has long been used to assess the condition of the high-voltage insulation in motor and generator stator windings. Past research has shown that motor and generator operating parameters such as voltage, power output, gas pressure, and stator winding temperature can have an important impact on the PD levels, and thus must be controlled if useful trends in PD activity over time are to be obtained. Over the years, results have been collected that indicate humidity may also be a factor that needs to be monitored. In addition, some simple laboratory experiments have been performed to verify that humidity can change the PD. When applying online PD testing to assess stator winding insulation condition, users must be aware of the influence of humidity on the measured PD activity to properly interpret the results.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"36 1","pages":"579-581"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89103284","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995895
Y. Tian, Paul Lewin, A. E. Davies, S. Sutton, S. Swingler
Partial discharge (PD) detection, signal analysis and pattern identification, using acoustic emission measurements and the back-propagation (BP) artificial neural network (ANN) have been investigated. The measured signals were processed using three-dimensional patterns and short duration Fourier transforms (SDFT). Investigation indicates that using BP ANN with the SDFT components for classifying different PD patterns provides very good overall results.
{"title":"Application of acoustic emission techniques and artificial neural networks to partial discharge classification","authors":"Y. Tian, Paul Lewin, A. E. Davies, S. Sutton, S. Swingler","doi":"10.1109/ELINSL.2002.995895","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995895","url":null,"abstract":"Partial discharge (PD) detection, signal analysis and pattern identification, using acoustic emission measurements and the back-propagation (BP) artificial neural network (ANN) have been investigated. The measured signals were processed using three-dimensional patterns and short duration Fourier transforms (SDFT). Investigation indicates that using BP ANN with the SDFT components for classifying different PD patterns provides very good overall results.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"64 1","pages":"119-123"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89186234","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995888
J. Bostrom, E. Marsden, R. N. Hampton, U. Nilsson, H. Lennartsson
Cleanliness is one of the most important quality criteria for high performance XLPE insulation materials. The cleanliness level that is routinely achievable today forms the foundation for development of smaller cable constructions and the continued development of 500 kV XLPE cable system. The cleanliness specifications for these compounds need to consider the typical geometry and electrical nature of any contaminant. A combination of quality control techniques makes it possible to identify frequency, type and geometry of contaminants. By applying theoretical models, calculation of electrical stress enhancement from these contaminants can be assessed with improved reliability.
{"title":"Electrical stress enhancement of contaminants in XLPE insulation as quality control criteria","authors":"J. Bostrom, E. Marsden, R. N. Hampton, U. Nilsson, H. Lennartsson","doi":"10.1109/ELINSL.2002.995888","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995888","url":null,"abstract":"Cleanliness is one of the most important quality criteria for high performance XLPE insulation materials. The cleanliness level that is routinely achievable today forms the foundation for development of smaller cable constructions and the continued development of 500 kV XLPE cable system. The cleanliness specifications for these compounds need to consider the typical geometry and electrical nature of any contaminant. A combination of quality control techniques makes it possible to identify frequency, type and geometry of contaminants. By applying theoretical models, calculation of electrical stress enhancement from these contaminants can be assessed with improved reliability.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"2 1","pages":"91-95"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89315368","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995996
F. Wester, E. Gulski, J. Smit, E. Groot
In this paper, fundamental aspects of on-line PD diagnostics are evaluated, especially in respect to the information transferability of off-line PD diagnostics. In particular, different influencing aspects of on-line PD diagnostics are investigated. Finally, based on field measurements a study for the usefulness and effectiveness of the practical application of on-line PD detection diagnostic for power cables, as a pre-selecting method for off-line diagnostics is discussed.
{"title":"Aspect of on-line and off-line PD diagnosis of distribution power cables","authors":"F. Wester, E. Gulski, J. Smit, E. Groot","doi":"10.1109/ELINSL.2002.995996","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995996","url":null,"abstract":"In this paper, fundamental aspects of on-line PD diagnostics are evaluated, especially in respect to the information transferability of off-line PD diagnostics. In particular, different influencing aspects of on-line PD diagnostics are investigated. Finally, based on field measurements a study for the usefulness and effectiveness of the practical application of on-line PD detection diagnostic for power cables, as a pre-selecting method for off-line diagnostics is discussed.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"28 1","pages":"553-556"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89315631","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995876
Wei Wang, Wufeng Li, C.R. Li, L. Ding, Q. Su, C. Chang
The on-line monitoring of partial discharge on generators is more and more widely used to estimate the insulation condition of generator stator windings. In this paper a new detector for on-line monitoring of partial discharges of generators was introduced. The measurement of partial discharges was carried out on some generator model bars in a laboratory using the new detector. Features of different types of PD were analyzed using the spectrums of Hq(/spl phi/), Hn(/spl phi/) and Hn(q). Some primary results from field test are reported for a detector installed on a turbine generator in a power plant located in Shanxi Province of China.
{"title":"The estimation of insulation condition of generators by on-line monitoring of partial discharges using a new detector","authors":"Wei Wang, Wufeng Li, C.R. Li, L. Ding, Q. Su, C. Chang","doi":"10.1109/ELINSL.2002.995876","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995876","url":null,"abstract":"The on-line monitoring of partial discharge on generators is more and more widely used to estimate the insulation condition of generator stator windings. In this paper a new detector for on-line monitoring of partial discharges of generators was introduced. The measurement of partial discharges was carried out on some generator model bars in a laboratory using the new detector. Features of different types of PD were analyzed using the spectrums of Hq(/spl phi/), Hn(/spl phi/) and Hn(q). Some primary results from field test are reported for a detector installed on a turbine generator in a power plant located in Shanxi Province of China.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"23 1","pages":"40-43"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83568176","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995893
S. Hvidsten, H. Faremo, R. Eriksson, Wei Min
The results show that the degree of water treeing in HV XLPE cables (36 kV and above) is strongly dependent upon the cable design and the service (system) voltage. The water trees are typically relatively short, but their density is similar to that observed in medium voltage cables with similar design. The results from the nondestructive diagnostic testing show that it can be possible to detect water treeing also in old high voltage cables extending diagnostic techniques developed for medium voltage cables.
{"title":"Water treeing and condition assessment of high voltage XLPE cables","authors":"S. Hvidsten, H. Faremo, R. Eriksson, Wei Min","doi":"10.1109/ELINSL.2002.995893","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995893","url":null,"abstract":"The results show that the degree of water treeing in HV XLPE cables (36 kV and above) is strongly dependent upon the cable design and the service (system) voltage. The water trees are typically relatively short, but their density is similar to that observed in medium voltage cables with similar design. The results from the nondestructive diagnostic testing show that it can be possible to detect water treeing also in old high voltage cables extending diagnostic techniques developed for medium voltage cables.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"83 1","pages":"112-115"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85602992","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995905
T. Leibfried, A. Kachler
A lot of power transformers currently in operation have reached a critical age with an operating time of 30 years and more. Utilities have to make a decision either continuing to use these transformers or replacing them. As a basis for this decision, information about the condition of the currently operating power transformers is required. Ageing processes are caused by dielectric, chemical, thermal and electrodynamic stresses. They are of very complex nature. As an example, water in the solid insulation material acts as a catalyst and enforces the ageing processes. Due to variable load there is a complex temperature dependent moisture dynamic behaviour of the oil paper insulation system. Well-known methods like Karl-Fischer-Titration and dew point measurement cannot be applied on transformers in operation since it is risky and difficult to open the transformer for getting a material sample. New methods of dielectric spectroscopy have been developed to overcome this implication. The PDC-analysis (polarisation and depolarisation current analysis) is a nondestructive method for determining the moisture content in the solid insulation material of a power transformer. On the basis of this reliable analysis one can decide about further actions like an on-site drying of the active part. This paper presents the PDC technique and results of measurements on new and aged transformers.
{"title":"Insulation diagnostics on power transformers using the polarisation and depolarisation current (PDC) analysis","authors":"T. Leibfried, A. Kachler","doi":"10.1109/ELINSL.2002.995905","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995905","url":null,"abstract":"A lot of power transformers currently in operation have reached a critical age with an operating time of 30 years and more. Utilities have to make a decision either continuing to use these transformers or replacing them. As a basis for this decision, information about the condition of the currently operating power transformers is required. Ageing processes are caused by dielectric, chemical, thermal and electrodynamic stresses. They are of very complex nature. As an example, water in the solid insulation material acts as a catalyst and enforces the ageing processes. Due to variable load there is a complex temperature dependent moisture dynamic behaviour of the oil paper insulation system. Well-known methods like Karl-Fischer-Titration and dew point measurement cannot be applied on transformers in operation since it is risky and difficult to open the transformer for getting a material sample. New methods of dielectric spectroscopy have been developed to overcome this implication. The PDC-analysis (polarisation and depolarisation current analysis) is a nondestructive method for determining the moisture content in the solid insulation material of a power transformer. On the basis of this reliable analysis one can decide about further actions like an on-site drying of the active part. This paper presents the PDC technique and results of measurements on new and aged transformers.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"428 1","pages":"170-173"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86687294","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 : 2002-04-07DOI: 10.1109/ELINSL.2002.995898
J. Lapworth
A new method of interpreting dissolved gas analysis results for power transformers is described which attempts to tackle what is seen as the main weakness of existing schemes: the difficulty of defining a normal condition. A simple scoring system based on results from known problems is used to provide a consistent and objective assessment of the seriousness of results, to improve the effectiveness of life management decisions.
{"title":"A novel approach (scoring system) for integrating dissolved gas analysis results into a life management system","authors":"J. Lapworth","doi":"10.1109/ELINSL.2002.995898","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995898","url":null,"abstract":"A new method of interpreting dissolved gas analysis results for power transformers is described which attempts to tackle what is seen as the main weakness of existing schemes: the difficulty of defining a normal condition. A simple scoring system based on results from known problems is used to provide a consistent and objective assessment of the seriousness of results, to improve the effectiveness of life management decisions.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"47 1","pages":"137-144"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79048918","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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