Pub Date : 2019-06-01DOI: 10.1109/EIC43217.2019.9046630
P. Seri, L. Cirioni, H. Naderiallaf, G. Montanari, R. Hebner, A. Gattozzi, Xianyong Feng
In this paper the AC and DC partial discharge inception voltages, PDIV, are modeled and validated through measurements performed on multi-layer flat specimens with artificial defects. The results highlight that, depending on temperature and material conductivity, there can be a large difference between PDIV under DC and AC, which depends on insulation temperature, thus, e.g., cable loading. Indeed PDIV-DC can be much larger than PDIV-AC at room temperature, but the two values can be very close (with PDIV -DC being even smaller than PDIV-AC) at maximum operating temperature, i.e. full load.
{"title":"Partial Discharge Inception Voltage in DC insulation systems: a comparison with AC voltage supply","authors":"P. Seri, L. Cirioni, H. Naderiallaf, G. Montanari, R. Hebner, A. Gattozzi, Xianyong Feng","doi":"10.1109/EIC43217.2019.9046630","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046630","url":null,"abstract":"In this paper the AC and DC partial discharge inception voltages, PDIV, are modeled and validated through measurements performed on multi-layer flat specimens with artificial defects. The results highlight that, depending on temperature and material conductivity, there can be a large difference between PDIV under DC and AC, which depends on insulation temperature, thus, e.g., cable loading. Indeed PDIV-DC can be much larger than PDIV-AC at room temperature, but the two values can be very close (with PDIV -DC being even smaller than PDIV-AC) at maximum operating temperature, i.e. full load.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125412297","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}
This work aims to report the influence of ambient humidity on partial discharge inception voltage (PDIV) and lifetime (endurance) of the insulation for inverter-fed motors. The PDIV on polyimide film and rotor bar insulated by NOMEX at sinusoidal voltages with 50 Hz frequency and the endurance tests of inverter-fed motor turn insulation under repetitive unipolar impulsive voltages with 10 ns rise time and 200 ns voltage on-time were performed at four relative humidity (RH), i.e. 40%, 60%, 80%, 95%, controlling the ambient temperature at 50 °C. Experimental results show that both the PDIV and endurance decrease significantly with increasing RH. Accordingly, the influence of ambient humidity on the test results should be carefully considered when performing PDIV and endurance tests on the insulation of low-voltage and high-voltage inverter-fed motors according to IEC standards.
{"title":"Influence of Ambient Humidity on PDIV and Endurance of Inverter-fed Motor Insulation","authors":"Peng Wang, Yanghao Gu, Qi Wu, A. Cavallini, Qin Zhang, Jiawei Zhang","doi":"10.1109/EIC43217.2019.9046593","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046593","url":null,"abstract":"This work aims to report the influence of ambient humidity on partial discharge inception voltage (PDIV) and lifetime (endurance) of the insulation for inverter-fed motors. The PDIV on polyimide film and rotor bar insulated by NOMEX at sinusoidal voltages with 50 Hz frequency and the endurance tests of inverter-fed motor turn insulation under repetitive unipolar impulsive voltages with 10 ns rise time and 200 ns voltage on-time were performed at four relative humidity (RH), i.e. 40%, 60%, 80%, 95%, controlling the ambient temperature at 50 °C. Experimental results show that both the PDIV and endurance decrease significantly with increasing RH. Accordingly, the influence of ambient humidity on the test results should be carefully considered when performing PDIV and endurance tests on the insulation of low-voltage and high-voltage inverter-fed motors according to IEC standards.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115534299","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046580
Yang Yang, M. Darwish, M. Moghadam, Dominic Quennell, Ashkan Hajiloo
With the development of offshore wind power, long-distance cable transmission is required to transmit fluctuating power. A Capacitive Transfer System (CTS) cable was proposed to decrease the line reactance to increase the transmission capability by the designed dielectric layers between strands and special connection of the strands. Because of the dielectric layers between strands, the paths of eddy currents between strands are blocked. In addition, the dielectric layers between strands work as a long capacitor to cancel the line inductive reactance. The geometry design of CTS IV L model is demonstrated in COMSOL. Finally, a set of laboratory tests are carried out to verify the reactive power compensation.
随着海上风电的发展，需要远距离电缆传输来传输波动电力。提出了一种电容传输系统(CTS)电缆，通过设计导线间的介电层和导线间的特殊连接来降低线路电抗，提高传输能力。由于股线之间的介电层，股线之间涡流的路径被阻挡。此外，导线之间的介电层作为一个长电容来抵消线路电感电抗。在COMSOL中演示了CTS IV L模型的几何设计。最后，进行了一组实验室试验，对无功补偿进行了验证。
{"title":"Capacitive Transfer Cable and Its Performance in Comparison with Conventional Solid Insulated Cable","authors":"Yang Yang, M. Darwish, M. Moghadam, Dominic Quennell, Ashkan Hajiloo","doi":"10.1109/EIC43217.2019.9046580","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046580","url":null,"abstract":"With the development of offshore wind power, long-distance cable transmission is required to transmit fluctuating power. A Capacitive Transfer System (CTS) cable was proposed to decrease the line reactance to increase the transmission capability by the designed dielectric layers between strands and special connection of the strands. Because of the dielectric layers between strands, the paths of eddy currents between strands are blocked. In addition, the dielectric layers between strands work as a long capacitor to cancel the line inductive reactance. The geometry design of CTS IV L model is demonstrated in COMSOL. Finally, a set of laboratory tests are carried out to verify the reactive power compensation.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116244445","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046588
M. Gunasekaran
This paper deals with polymer-impregnated concrete (PIC). It is the precursor to the polymer concrete (PC) insulating material currently in vogue in the industry all over the world. Even though it is based on a hydraulic cement system, synergism with an imposed polymeric phase in its matrix has yielded a super dielectric and insulating structural material with great versatility. A brief overview of PIC's evolution in North America, its properties, and its potential for futuristic applications, is presented.
{"title":"Polymer-Impregnated Concrete Insulators/Insulating Structures","authors":"M. Gunasekaran","doi":"10.1109/EIC43217.2019.9046588","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046588","url":null,"abstract":"This paper deals with polymer-impregnated concrete (PIC). It is the precursor to the polymer concrete (PC) insulating material currently in vogue in the industry all over the world. Even though it is based on a hydraulic cement system, synergism with an imposed polymeric phase in its matrix has yielded a super dielectric and insulating structural material with great versatility. A brief overview of PIC's evolution in North America, its properties, and its potential for futuristic applications, is presented.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122856750","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046614
R. Kuppuswamy, Sandy Rainey
It is generally accepted within the industry that terminal partial discharge (PD) measurements are less sensitive to electrical discharges deep within the stator windings. Typically, on large generators, electrical defects beyond 10-15% from the line-end of the stator winding cannot be detected. This equates to first 2 to 3 coils from the line-end. Therefore, other measures are necessary to expand the zone of detection. Large generators and motors are typically equipped with 12 or more resistive temperature detectors (RTDs) embedded into the stator winding. The RTD acts as an RF-antenna placed into a winding that is sensitive to the high frequency component of an electromagnetic pulse caused by PD. The RTD is both capacitively and magnetically coupled to the PD pulse originated by a discharge. Calibration tests show that the RTD is useful in assessing PD levels within a few adjacent slots from its location. Using case examples, comparison between two forms of PD measurements is presented - (a) Conventional terminal PD measurements using three 80pF epoxy mica capacitors on the line-side of each stator winding-phase; (b) Deep winding PD monitoring using embedded resistive temperature detectors (RTDs) as PD sensors. For the latter case, few RTDs in each stator winding-phase were selected to cover high and low potential slots in the winding. Detecting PD at lower potential slots using RTDs allows to detect faults caused by loose bars in the slot, “vibration sparking”. This report synthesizes the overall PD monitoring experience using collection of experiences from hydro and turbo generators. The focus is placed on demonstrating how RTDs have helped catch faults close to the winding neutral. Defect location capability of RTD PD sensors is demonstrated and results compared with corona probe measurements, which is traditionally used for defect location.
{"title":"Synthesis of Experiences using Resistive Temperature Detectors (RTD) as PD Sensors for Detecting and Locating Electrical Defects inside Generator Stator Windings","authors":"R. Kuppuswamy, Sandy Rainey","doi":"10.1109/EIC43217.2019.9046614","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046614","url":null,"abstract":"It is generally accepted within the industry that terminal partial discharge (PD) measurements are less sensitive to electrical discharges deep within the stator windings. Typically, on large generators, electrical defects beyond 10-15% from the line-end of the stator winding cannot be detected. This equates to first 2 to 3 coils from the line-end. Therefore, other measures are necessary to expand the zone of detection. Large generators and motors are typically equipped with 12 or more resistive temperature detectors (RTDs) embedded into the stator winding. The RTD acts as an RF-antenna placed into a winding that is sensitive to the high frequency component of an electromagnetic pulse caused by PD. The RTD is both capacitively and magnetically coupled to the PD pulse originated by a discharge. Calibration tests show that the RTD is useful in assessing PD levels within a few adjacent slots from its location. Using case examples, comparison between two forms of PD measurements is presented - (a) Conventional terminal PD measurements using three 80pF epoxy mica capacitors on the line-side of each stator winding-phase; (b) Deep winding PD monitoring using embedded resistive temperature detectors (RTDs) as PD sensors. For the latter case, few RTDs in each stator winding-phase were selected to cover high and low potential slots in the winding. Detecting PD at lower potential slots using RTDs allows to detect faults caused by loose bars in the slot, “vibration sparking”. This report synthesizes the overall PD monitoring experience using collection of experiences from hydro and turbo generators. The focus is placed on demonstrating how RTDs have helped catch faults close to the winding neutral. Defect location capability of RTD PD sensors is demonstrated and results compared with corona probe measurements, which is traditionally used for defect location.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122060604","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046586
Ehsan Zeynali, Ryan Bridges, B. Kordi
Printed circuit boards (PCB) are key components of any electronic system. The reliability of PCBs under operating conditions is an important factor to ensure the performance of the system. In recent years, the electrical power demand in more-electric aircraft has significantly increased. To provide more power, the operating voltage is increased which imposes a higher level of electrical stress on the insulation system of PCBs and, therefore, a higher risk of failure. Partial discharges in PCBs are more likely to happen within the air gap. To improve the insulation of PCBs, they are coated with an insulation material. In this study, test boards with two parallel traces were fabricated and coated based on aerospace industry approved standards. The boards were energized using a 60-Hz adjustable high voltage source. Partial discharges were measured for silicone-coated test boards under pollution and conductive particles conditions. The impact of pollution location on partial discharge was investigated. Besides, the breakdown voltage of test boards was measured under different coating conditions and low air pressure. An increased withstand voltage for coated boards was confirmed.
{"title":"Investigation of Partial Discharge in Aircraft Conformally-Coated Printed Circuit Boards","authors":"Ehsan Zeynali, Ryan Bridges, B. Kordi","doi":"10.1109/EIC43217.2019.9046586","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046586","url":null,"abstract":"Printed circuit boards (PCB) are key components of any electronic system. The reliability of PCBs under operating conditions is an important factor to ensure the performance of the system. In recent years, the electrical power demand in more-electric aircraft has significantly increased. To provide more power, the operating voltage is increased which imposes a higher level of electrical stress on the insulation system of PCBs and, therefore, a higher risk of failure. Partial discharges in PCBs are more likely to happen within the air gap. To improve the insulation of PCBs, they are coated with an insulation material. In this study, test boards with two parallel traces were fabricated and coated based on aerospace industry approved standards. The boards were energized using a 60-Hz adjustable high voltage source. Partial discharges were measured for silicone-coated test boards under pollution and conductive particles conditions. The impact of pollution location on partial discharge was investigated. Besides, the breakdown voltage of test boards was measured under different coating conditions and low air pressure. An increased withstand voltage for coated boards was confirmed.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124241607","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046575
G. Stone, H. Sedding, R. Wheeler, Alastair Wilson
Stator coils and bars from 10 different hydrogenerators with a wide variety of ratings and operating hours were dissected to determine the degree of aging of the stator groundwall insulation. The bars and coils came from machines that were being rewound due to failure, old age or uprating. In cases where the coils/bars were not damaged during extraction from the generator, off-line electrical tests were performed and compared to the condition of the groundwall insulation, as determined by dissections. Only one of the windings had essentially unaged insulation. All the rest showed various degrees of thermal or thermo-mechanical aging. Only one of the 10 windings also showed severe aging due to surface partial discharge. The coin tap test was a good predictor of the degree of thermal and thermo-mechanical (load cycling) aging. The PD test was a good predictor of the coils/bars that had any of the three types of aging.
{"title":"Observations from the Dissection of Several Aged Stator Coils from Different Hydrogenerators","authors":"G. Stone, H. Sedding, R. Wheeler, Alastair Wilson","doi":"10.1109/EIC43217.2019.9046575","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046575","url":null,"abstract":"Stator coils and bars from 10 different hydrogenerators with a wide variety of ratings and operating hours were dissected to determine the degree of aging of the stator groundwall insulation. The bars and coils came from machines that were being rewound due to failure, old age or uprating. In cases where the coils/bars were not damaged during extraction from the generator, off-line electrical tests were performed and compared to the condition of the groundwall insulation, as determined by dissections. Only one of the windings had essentially unaged insulation. All the rest showed various degrees of thermal or thermo-mechanical aging. Only one of the 10 windings also showed severe aging due to surface partial discharge. The coin tap test was a good predictor of the degree of thermal and thermo-mechanical (load cycling) aging. The PD test was a good predictor of the coils/bars that had any of the three types of aging.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126327290","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046638
A. Rehman, Yong Zhao, Guorui Huang, Yihan Zhao, Yu Chen, Yonghong Cheng, Toshikatsu Tanaka, Peng Wang
Nowadays harnessing electric power through wind is one of the most important forms of sustainable power production. A doubly fed induction generator is commonly used in wind turbines, however short circuit fault of rotor windings severely affect its performance. So for this purpose, an experimental platform has been designed to detect the inter turn short circuit fault in rotor windings in doubly fed induction generator using a magnetic flux measuring coil antenna. The experimental platform has the following nameplate data: 100 kW wound rotor induction machine, supply voltage 400V, rated speed 1800 rpm, stator/rotor connection $Delta/mathbf{Y}$ and rated current 129/45 amp. The experimental setup comprises of the following subsystem: a motor to drive the generator, a condition monitoring system to acquire the date, a control system to regulate the speed and to perform the short circuit fault, a short circuit cabinet to make connection between the generator and control system. The experiment was performed at a no load, 25 kW and 50 kW load conditions. A magnetic field measuring coil antenna having a frequency range of 20 Hz - 500 kHz was placed on the axial side of the generator to acquire the output voltage. An obvious change in the amplitude of output voltage at frequencies of 250 Hz, 270 Hz and 280 Hz was observed, when the inter turn short circuit fault occurred. Which serves as a clear indication of the short circuit fault in the windings. The amplitude at these frequencies increases as the fault level increases, which is helpful for testing the fault severity. The results show that monitoring the search coil voltage is more effective and advance way than the motor current signature analysis to detect the inter turn short fault in rotor windings in doubly fed induction generator.
{"title":"Fault Diagnosis in Rotor Windings in DFIG using Magnetic Flux Measurement Coil Antenna","authors":"A. Rehman, Yong Zhao, Guorui Huang, Yihan Zhao, Yu Chen, Yonghong Cheng, Toshikatsu Tanaka, Peng Wang","doi":"10.1109/EIC43217.2019.9046638","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046638","url":null,"abstract":"Nowadays harnessing electric power through wind is one of the most important forms of sustainable power production. A doubly fed induction generator is commonly used in wind turbines, however short circuit fault of rotor windings severely affect its performance. So for this purpose, an experimental platform has been designed to detect the inter turn short circuit fault in rotor windings in doubly fed induction generator using a magnetic flux measuring coil antenna. The experimental platform has the following nameplate data: 100 kW wound rotor induction machine, supply voltage 400V, rated speed 1800 rpm, stator/rotor connection $Delta/mathbf{Y}$ and rated current 129/45 amp. The experimental setup comprises of the following subsystem: a motor to drive the generator, a condition monitoring system to acquire the date, a control system to regulate the speed and to perform the short circuit fault, a short circuit cabinet to make connection between the generator and control system. The experiment was performed at a no load, 25 kW and 50 kW load conditions. A magnetic field measuring coil antenna having a frequency range of 20 Hz - 500 kHz was placed on the axial side of the generator to acquire the output voltage. An obvious change in the amplitude of output voltage at frequencies of 250 Hz, 270 Hz and 280 Hz was observed, when the inter turn short circuit fault occurred. Which serves as a clear indication of the short circuit fault in the windings. The amplitude at these frequencies increases as the fault level increases, which is helpful for testing the fault severity. The results show that monitoring the search coil voltage is more effective and advance way than the motor current signature analysis to detect the inter turn short fault in rotor windings in doubly fed induction generator.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"202 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126424654","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046552
Asha Sharma, S. Basu, N. Gupta
Inclusion of a small quantity of metal oxide nano-fillers significantly improves electrical and other properties of a polymer dielectric; literature attributes this improvement to the interphase region between matrix and nano-particle. Till date, direct observation of the interfacial region has not been possible. The current work explores the possibility of detecting the interphase using Electrostatic Force Microscopy (EFM). Experiments are performed on epoxy-based nanocomposites with barium titanate nano-fillers. EFM detects the phase shift around a single nanoparticle embedded in the polymer matrix. A computational model, simulating the experimental conditions, is used to generate the EFM phase shift numerically. This is matched with the experimental EFM phase image, to obtain an estimate of the interphase permittivity and thickness. Statistical analysis of particle size in powder form and when embedded in the epoxy lends credence to the estimates obtained.
{"title":"Estimation of Interphase Permittivity and Interphase Thickness in Epoxy based Nanocomposites using Electrostatic Force Microscopy","authors":"Asha Sharma, S. Basu, N. Gupta","doi":"10.1109/EIC43217.2019.9046552","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046552","url":null,"abstract":"Inclusion of a small quantity of metal oxide nano-fillers significantly improves electrical and other properties of a polymer dielectric; literature attributes this improvement to the interphase region between matrix and nano-particle. Till date, direct observation of the interfacial region has not been possible. The current work explores the possibility of detecting the interphase using Electrostatic Force Microscopy (EFM). Experiments are performed on epoxy-based nanocomposites with barium titanate nano-fillers. EFM detects the phase shift around a single nanoparticle embedded in the polymer matrix. A computational model, simulating the experimental conditions, is used to generate the EFM phase shift numerically. This is matched with the experimental EFM phase image, to obtain an estimate of the interphase permittivity and thickness. Statistical analysis of particle size in powder form and when embedded in the epoxy lends credence to the estimates obtained.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121590945","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 : 2019-06-01DOI: 10.1109/EIC43217.2019.9046516
C. Hudon, M. Lévesque, S. Bernier, H. Provencher, É. Cloutier-Rioux, Yoon Duk Seol
Partial discharge (PD) measurements have been carried out for years on generators, individual bars and form-wound coils. Even if the determination of quantitative criteria for what is considered normal and abnormal PD still represents a challenge in the industry, phase resolved partial discharge (PRPD) pattern recognition has been successfully used to recognize the nature of PD activity [1-3]. In the present work, conventional PD measurements using a capacitive coupler were compared with measurements made using an antenna to detect localized PD sites on individual bars and coils. The antenna was used to map localized PD sites along the entire length of the straight portion. The measurements were carried out on bars and coils of four different designs. The results revealed that the two measurement techniques give complementary information. It was found that the antenna had a limited sensitivity to PD occurring in micro-voids occluded within the groundwall insulation. For most of the bars and coils tested, the antenna did not detect any signal, even if there was always PD activity measured with the standard capacitive coupler. However, some of the specimens tested with the antenna revealed localized PD sites with distinctive PRPD patterns, suggesting that some anomalies were present at these sites. This information can thereafter be used to determine where to perform dissection of bars and coils.
{"title":"Scanning Individual Stator Bars and Coils with an Antenna to Detect Localized Partial Discharges","authors":"C. Hudon, M. Lévesque, S. Bernier, H. Provencher, É. Cloutier-Rioux, Yoon Duk Seol","doi":"10.1109/EIC43217.2019.9046516","DOIUrl":"https://doi.org/10.1109/EIC43217.2019.9046516","url":null,"abstract":"Partial discharge (PD) measurements have been carried out for years on generators, individual bars and form-wound coils. Even if the determination of quantitative criteria for what is considered normal and abnormal PD still represents a challenge in the industry, phase resolved partial discharge (PRPD) pattern recognition has been successfully used to recognize the nature of PD activity [1-3]. In the present work, conventional PD measurements using a capacitive coupler were compared with measurements made using an antenna to detect localized PD sites on individual bars and coils. The antenna was used to map localized PD sites along the entire length of the straight portion. The measurements were carried out on bars and coils of four different designs. The results revealed that the two measurement techniques give complementary information. It was found that the antenna had a limited sensitivity to PD occurring in micro-voids occluded within the groundwall insulation. For most of the bars and coils tested, the antenna did not detect any signal, even if there was always PD activity measured with the standard capacitive coupler. However, some of the specimens tested with the antenna revealed localized PD sites with distinctive PRPD patterns, suggesting that some anomalies were present at these sites. This information can thereafter be used to determine where to perform dissection of bars and coils.","PeriodicalId":340602,"journal":{"name":"2019 IEEE Electrical Insulation Conference (EIC)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132215029","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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