Pub Date : 2002-04-07DOI: 10.1109/ELINSL.2002.996003
D. Gross
With respect to the basic gas discharge physics, the rise time of an electron avalanche under nitrogen atmosphere results in a partial discharge signal bandwidth of several hundreds of MHz. However, in terms of high frequency properties, a rotating machine acts as a highly complex network. Mismatch of impedance and other effects hamper the applicability of different frequency bands for partial discharge testing. The epoxy-mica insulation system widely tolerates partial discharge. Thus, partial discharge activity often serves as an indicator for other defect mechanism, such as mechanical, thermal, or environmental influence.
{"title":"Partial discharge measurement and monitoring on rotating machines","authors":"D. Gross","doi":"10.1109/ELINSL.2002.996003","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.996003","url":null,"abstract":"With respect to the basic gas discharge physics, the rise time of an electron avalanche under nitrogen atmosphere results in a partial discharge signal bandwidth of several hundreds of MHz. However, in terms of high frequency properties, a rotating machine acts as a highly complex network. Mismatch of impedance and other effects hamper the applicability of different frequency bands for partial discharge testing. The epoxy-mica insulation system widely tolerates partial discharge. Thus, partial discharge activity often serves as an indicator for other defect mechanism, such as mechanical, thermal, or environmental influence.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"10 1","pages":"570-574"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83662401","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.2002.995877
M. Fenger, B. Lloyd, J. Pedersen
Random wound stator windings in motors operating in utility and industrial plants through out the world have been reported to suffer from premature winding failures. Although several failure mechanisms exist, some of these failures have been caused by exposure to fast rise-time voltage surges coming from inverter drives. Dissection of failed stator windings have indicated that partial discharges have been a predominate cause of the stator failure. Partial discharges may occur between turns during fast rise-time voltage surges and result in degradation of the organic magnet wire enamel impregnants, eventually resulting in turn-to-turn or phase-to-phase failures. In this paper, measurements of the surge environment for several motors are presented, some of which have suffered stator winding failures. Inspection of the winding after failure showed local melting caused by puncture of the insulation. Utilizing custom PD detection instrumentation and a variable rise-time surge generator, measurements of partial discharge inception voltage (DIV) have been made. Combining the DIV data; with the actual surge environment from inverter drive allows assessment of the risk of motor failure due to PD related insulation breakdown.
{"title":"Surge related partial discharges resulting from IFDs applied to random wound motors","authors":"M. Fenger, B. Lloyd, J. Pedersen","doi":"10.1109/ELINSL.2002.995877","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995877","url":null,"abstract":"Random wound stator windings in motors operating in utility and industrial plants through out the world have been reported to suffer from premature winding failures. Although several failure mechanisms exist, some of these failures have been caused by exposure to fast rise-time voltage surges coming from inverter drives. Dissection of failed stator windings have indicated that partial discharges have been a predominate cause of the stator failure. Partial discharges may occur between turns during fast rise-time voltage surges and result in degradation of the organic magnet wire enamel impregnants, eventually resulting in turn-to-turn or phase-to-phase failures. In this paper, measurements of the surge environment for several motors are presented, some of which have suffered stator winding failures. Inspection of the winding after failure showed local melting caused by puncture of the insulation. Utilizing custom PD detection instrumentation and a variable rise-time surge generator, measurements of partial discharge inception voltage (DIV) have been made. Combining the DIV data; with the actual surge environment from inverter drive allows assessment of the risk of motor failure due to PD related insulation breakdown.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"21 1","pages":"44-48"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86190916","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.2002.995941
W. McDermid
Power transformers installed in the 1960s and 1970s were protected by surge arresters with gaps and silicon carbide valve elements. Many of these arresters are still in service but the population is declining. By 1980, gapless zinc oxide arresters were being installed in all new installations. There are two reliability issues involving surge arresters: adequacy of protection and consequential damage resulting from in-service failure.
{"title":"Reliability of station class surge arresters","authors":"W. McDermid","doi":"10.1109/ELINSL.2002.995941","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995941","url":null,"abstract":"Power transformers installed in the 1960s and 1970s were protected by surge arresters with gaps and silicon carbide valve elements. Many of these arresters are still in service but the population is declining. By 1980, gapless zinc oxide arresters were being installed in all new installations. There are two reliability issues involving surge arresters: adequacy of protection and consequential damage resulting from in-service failure.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"96 1","pages":"320-322"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86677528","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.2002.995981
R. Bruetsch, R. Schwander, F. Wolf, Marco Naegelin
The driving force of material and process development in the insulation technology of rotating high voltage machines has changed in the last ten to fifteen years. Being mainly technology driven in the past, cost has become the determining factor in the industry. Improvements in products or processing are only accepted if they reduce overall cost. On the other hand, high voltage motors and generators are long-life capital goods and a reduction in reliability cannot be tolerated. To be successful in the market any development of new insulating materials has to reflect these facts. For this reason a new range of fast curing products for the consolidation of Roebel bars and double layer coils has been developed. The application of the new fast curing materials can be automated using new types of equipment for the production and consolidation of Roebel bars. The new fast curing materials provide a substantial reduction of. processing time and saving of hot press capacity and energy. Together with the new automated Roebelling and application equipment they go a long way towards cost reduction in the production of rotating high voltage machines.
{"title":"New insulating materials and process equipment for the consolidation of coils and Roebel bars","authors":"R. Bruetsch, R. Schwander, F. Wolf, Marco Naegelin","doi":"10.1109/ELINSL.2002.995981","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995981","url":null,"abstract":"The driving force of material and process development in the insulation technology of rotating high voltage machines has changed in the last ten to fifteen years. Being mainly technology driven in the past, cost has become the determining factor in the industry. Improvements in products or processing are only accepted if they reduce overall cost. On the other hand, high voltage motors and generators are long-life capital goods and a reduction in reliability cannot be tolerated. To be successful in the market any development of new insulating materials has to reflect these facts. For this reason a new range of fast curing products for the consolidation of Roebel bars and double layer coils has been developed. The application of the new fast curing materials can be automated using new types of equipment for the production and consolidation of Roebel bars. The new fast curing materials provide a substantial reduction of. processing time and saving of hot press capacity and energy. Together with the new automated Roebelling and application equipment they go a long way towards cost reduction in the production of rotating high voltage machines.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"7 1","pages":"488-491"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81082895","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.2002.995870
Xiongwei Jiang, Gang Liu, Guangchun Zhang, Guangning Wu
Generally there are four types of defects inside the stator bar insulation of large generators, i.e. void, internal delamination, crack and delamination at conduct edge. It's evident that these four types of internal defects appear at the different stages of aging and play significantly different roles in the aging and ultimate failure of stator bar insulation. Thus it makes sense to distinguish them. In this paper, partial discharge experiments were performed on four elaborate model defects to establish a firm basis for the recognition of defect type.
{"title":"Study on PD characteristics of insulation internal defects of large generator stator bar","authors":"Xiongwei Jiang, Gang Liu, Guangchun Zhang, Guangning Wu","doi":"10.1109/ELINSL.2002.995870","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995870","url":null,"abstract":"Generally there are four types of defects inside the stator bar insulation of large generators, i.e. void, internal delamination, crack and delamination at conduct edge. It's evident that these four types of internal defects appear at the different stages of aging and play significantly different roles in the aging and ultimate failure of stator bar insulation. Thus it makes sense to distinguish them. In this paper, partial discharge experiments were performed on four elaborate model defects to establish a firm basis for the recognition of defect type.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"35 1","pages":"14-18"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79243246","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.2002.995987
C. Caironi, D. Brie, L. Durantay, A. Rezzoug
The development of time-frequency and time-scale transforms has progressed quickly for 20 years. This development and the progression of the numerical acquisition enable the utilization of these mathematical tools to analyze partial discharges (PD) in the induction motors insulation. Some papers have been written about the wavelet tools in order to analyze the partial discharges. This paper is a tutorial overview of the time frequency and time scale transforms applied to the PD analysis on the stators of the induction motors. In the first part two time-frequency transforms are introduced: short time Fourier transform and Wigner distribution. The mathematical tools for the implementation of the STFT are given. An example of extraction of a PD signal from numeric noise is given and its results discussed. In the second part the wavelets are presented on the same case study as for the time frequency transforms.
{"title":"Interest and utility of time frequency and time scale transforms in the partial discharges analysis","authors":"C. Caironi, D. Brie, L. Durantay, A. Rezzoug","doi":"10.1109/ELINSL.2002.995987","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995987","url":null,"abstract":"The development of time-frequency and time-scale transforms has progressed quickly for 20 years. This development and the progression of the numerical acquisition enable the utilization of these mathematical tools to analyze partial discharges (PD) in the induction motors insulation. Some papers have been written about the wavelet tools in order to analyze the partial discharges. This paper is a tutorial overview of the time frequency and time scale transforms applied to the PD analysis on the stators of the induction motors. In the first part two time-frequency transforms are introduced: short time Fourier transform and Wigner distribution. The mathematical tools for the implementation of the STFT are given. An example of extraction of a PD signal from numeric noise is given and its results discussed. In the second part the wavelets are presented on the same case study as for the time frequency transforms.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"27 1","pages":"516-522"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88072206","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.2002.995868
YongJun Kim, Ki-Chang Lee, D. Hwang, Doh-Young Park, S. Song
An instrument for the online monitoring of partial discharges becomes a more expensive investment option for generators of less than 100 MVA. For those machines, an economic unit of partial discharge measurements has been envisaged by simultaneously adopting a peak-detect-and-hold technique and an inherent analogue-to-digital (A/D) conversion function already embedded in a microprocessor or DSP (digital signal processor). This technique is named as hybrid conversion scheme.
{"title":"Hybrid conversion scheme for digital measurement of partial discharge spectra","authors":"YongJun Kim, Ki-Chang Lee, D. Hwang, Doh-Young Park, S. Song","doi":"10.1109/ELINSL.2002.995868","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995868","url":null,"abstract":"An instrument for the online monitoring of partial discharges becomes a more expensive investment option for generators of less than 100 MVA. For those machines, an economic unit of partial discharge measurements has been envisaged by simultaneously adopting a peak-detect-and-hold technique and an inherent analogue-to-digital (A/D) conversion function already embedded in a microprocessor or DSP (digital signal processor). This technique is named as hybrid conversion scheme.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"41 1","pages":"5-8"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79902119","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.2002.995867
K. Kimura, S. Itaya, M. Hikita
Power devices such as IGBT generate switching surges with steep-front waveform in sub-microsecond times. The highly repetitive surges may lead to unexpected insulation ageing of inverter-fed low-voltage motor windings, which have been designed without consideration of partial discharges (PD). Since the distance between adjacent magnet wires in a stator slot distributes in /spl mu/m to mm, so-called micro-discharge of very short gap with steep-front surges have been investigated. In order to evaluate PD ageing of polymer material under steep-front surges, we started the fundamental study of PD inception condition under step voltage with rise-time of nanoseconds. Using rod-plate electrodes with 20-50 /spl mu/m air gaps, time delay and charge buildup were measured simultaneously. It was found that charge builds up with PD instantly and decreases very slowly in comparison with repetitive pulse intervals of PWM. The effect of the surface charge on PD inception of the following surge is discussed.
功率器件如IGBT在亚微秒时间内产生具有陡前波形的开关浪涌。高度重复的浪涌可能导致逆变器供电的低压电机绕组意外的绝缘老化，这些绕组在设计时没有考虑局部放电(PD)。由于定子槽内相邻磁线之间的距离分布在/spl μ /m到mm之间，因此研究了极短间隙陡前浪涌的微放电现象。为了评价聚合物材料在陡坡前浪涌作用下的局部放电老化，我们对上升时间为纳秒级的阶跃电压下的局部放电起始条件进行了基础研究。采用气隙为20 ~ 50 μ m /spl μ m的棒板电极，同时测量时间延迟和电荷积累。研究发现，与PWM的重复脉冲间隔相比，PD的电荷积累是瞬间的，而减少的速度非常慢。讨论了表面电荷对后续浪涌PD起始的影响。
{"title":"Partial discharge behavior on PI film with microgap under steep-front step voltage","authors":"K. Kimura, S. Itaya, M. Hikita","doi":"10.1109/ELINSL.2002.995867","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995867","url":null,"abstract":"Power devices such as IGBT generate switching surges with steep-front waveform in sub-microsecond times. The highly repetitive surges may lead to unexpected insulation ageing of inverter-fed low-voltage motor windings, which have been designed without consideration of partial discharges (PD). Since the distance between adjacent magnet wires in a stator slot distributes in /spl mu/m to mm, so-called micro-discharge of very short gap with steep-front surges have been investigated. In order to evaluate PD ageing of polymer material under steep-front surges, we started the fundamental study of PD inception condition under step voltage with rise-time of nanoseconds. Using rod-plate electrodes with 20-50 /spl mu/m air gaps, time delay and charge buildup were measured simultaneously. It was found that charge builds up with PD instantly and decreases very slowly in comparison with repetitive pulse intervals of PWM. The effect of the surface charge on PD inception of the following surge is discussed.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"50 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80426023","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.2002.995871
YongJun Kim, D. Kang, D. Hwang, Doh-Young Park
A novel sensor called CGVPI (Coupler for Global VPI) has been developed for simple mounting on Global VPI surface of small rotating machines without deterioration of insulation system. Even for large rotating machines of individual VPI insulation, CGVPI can be a cost effective option by tremendously reducing the sensor installation process. This paper describes the laboratory test results of the sensor. In addition, the on-line partial discharge sensor called Ceramic Coupler is introduced.
为了在不破坏绝缘系统的前提下，简单地安装在小型旋转机械的全局VPI表面，研制了一种新型传感器CGVPI (Coupler for Global VPI)。即使对于单个VPI绝缘的大型旋转机器，CGVPI也可以通过大大减少传感器安装过程而成为一种具有成本效益的选择。本文介绍了该传感器的实验室测试结果。此外，还介绍了在线局部放电传感器陶瓷耦合器。
{"title":"A partial discharge coupler for global VPI (CGVPI) rotating machines","authors":"YongJun Kim, D. Kang, D. Hwang, Doh-Young Park","doi":"10.1109/ELINSL.2002.995871","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995871","url":null,"abstract":"A novel sensor called CGVPI (Coupler for Global VPI) has been developed for simple mounting on Global VPI surface of small rotating machines without deterioration of insulation system. Even for large rotating machines of individual VPI insulation, CGVPI can be a cost effective option by tremendously reducing the sensor installation process. This paper describes the laboratory test results of the sensor. In addition, the on-line partial discharge sensor called Ceramic Coupler is introduced.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"27 1","pages":"19-22"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83385695","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.2002.995939
X. Qi, S. Boggs
M.M. Perlmann (1989) has published models for conduction with "traps" (potential wells in the range of 0.8 eV) and with a combination of "traps" and "hopping sites" (potential wells in the range of 0.3 eV). However, the model for the latter does not extrapolate into the former as the number of hopping sites goes to zero. As a result, the conductivity cannot be computed for arbitrary densities of traps and hopping sites. A model has been developed based on quantum tunneling between the nearest neighbor and next nearest neighbor "traps" and "hopping sites" to calculate the hopping-induced conductivity, especially at high electric fields. The results are compared with Perlman's data.
{"title":"Model for high field conduction in doped polymers","authors":"X. Qi, S. Boggs","doi":"10.1109/ELINSL.2002.995939","DOIUrl":"https://doi.org/10.1109/ELINSL.2002.995939","url":null,"abstract":"M.M. Perlmann (1989) has published models for conduction with \"traps\" (potential wells in the range of 0.8 eV) and with a combination of \"traps\" and \"hopping sites\" (potential wells in the range of 0.3 eV). However, the model for the latter does not extrapolate into the former as the number of hopping sites goes to zero. As a result, the conductivity cannot be computed for arbitrary densities of traps and hopping sites. A model has been developed based on quantum tunneling between the nearest neighbor and next nearest neighbor \"traps\" and \"hopping sites\" to calculate the hopping-induced conductivity, especially at high electric fields. The results are compared with Perlman's data.","PeriodicalId":10532,"journal":{"name":"Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316)","volume":"23 1","pages":"313-316"},"PeriodicalIF":0.0,"publicationDate":"2002-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78580694","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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