Pub Date : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705426
Qasim Khan, S. Refaat, H. Abu-Rub, H. Toliyat, M. Olesz
This paper investigates the treeing phenomenon in polymeric materials such as crosslinked polyethylene (XLPE) that is widely used in medium and high voltage power cables as primary insulation. The modeling of electrical tree growth in the insulation from its initiation to breakdown is significant research work that illustrates the discharge dynamics and its impact on aging process in polymeric insulation. This study utilizes pulse sequence analysis (PSA) mapping and phase-resolved partial discharge (PRPD) pattern to model the tree growth and its correlation with the aging in the XLPE samples. The applied electric stress magnitude as a crucial treeing aspect is utilized to comprehend treeing and its relationship with insulation degradation. The tree mapping and plots exemplify and characterize treeing stages to work as a reliable diagnostic tool to determine aging in solid insulation.
{"title":"Modeling and Evaluation of Electric Treeing Phenomena in Polymeric Cable Insulation","authors":"Qasim Khan, S. Refaat, H. Abu-Rub, H. Toliyat, M. Olesz","doi":"10.1109/CEIDP50766.2021.9705426","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705426","url":null,"abstract":"This paper investigates the treeing phenomenon in polymeric materials such as crosslinked polyethylene (XLPE) that is widely used in medium and high voltage power cables as primary insulation. The modeling of electrical tree growth in the insulation from its initiation to breakdown is significant research work that illustrates the discharge dynamics and its impact on aging process in polymeric insulation. This study utilizes pulse sequence analysis (PSA) mapping and phase-resolved partial discharge (PRPD) pattern to model the tree growth and its correlation with the aging in the XLPE samples. The applied electric stress magnitude as a crucial treeing aspect is utilized to comprehend treeing and its relationship with insulation degradation. The tree mapping and plots exemplify and characterize treeing stages to work as a reliable diagnostic tool to determine aging in solid insulation.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"25 1","pages":"195-199"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88981402","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705474
Tianlei Xu, Weiyu Wang, Xi Pang, Z. Ye, Chongchong Chen, Peng Liu, Zongren Peng
High voltage direct current (HVDC) dry-type bushing is the key equipment in the ultra-high voltage direct current power transmission system. The temperature of its central conductor can go up to 105 °C under electrical/thermal working stresses. In order to study the effect of temperature on the dielectric performance, the space charge characteristics of epoxy/paper composites at different temperatures (20, 40, 60 and 80 °C) have been measured using a PEA method. Due to the discontinuity of permittivity and acoustic impedance at the interface of epoxy/paper composites, space charge distributions were preprocessed before analyzation. The experimental results show that a threshold (Eth) which directly reveals the inflection point of space charge accumulation is inversely proportional to temperature. Moreover, the direct-current (DC) steady state conductance currents were obtained under high electric fields at various temperatures. The threshold derived from conduction current measurement decreases as temperature increases, which is similar with the space charge measurement. Due to the measurement accuracy and the interference of pulse source, the threshold of space charge is generally smaller than that of conductance current.
{"title":"Research on Temperature Dependent Threshold of Epoxy/paper Composites through Space Charge Measurements","authors":"Tianlei Xu, Weiyu Wang, Xi Pang, Z. Ye, Chongchong Chen, Peng Liu, Zongren Peng","doi":"10.1109/CEIDP50766.2021.9705474","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705474","url":null,"abstract":"High voltage direct current (HVDC) dry-type bushing is the key equipment in the ultra-high voltage direct current power transmission system. The temperature of its central conductor can go up to 105 °C under electrical/thermal working stresses. In order to study the effect of temperature on the dielectric performance, the space charge characteristics of epoxy/paper composites at different temperatures (20, 40, 60 and 80 °C) have been measured using a PEA method. Due to the discontinuity of permittivity and acoustic impedance at the interface of epoxy/paper composites, space charge distributions were preprocessed before analyzation. The experimental results show that a threshold (Eth) which directly reveals the inflection point of space charge accumulation is inversely proportional to temperature. Moreover, the direct-current (DC) steady state conductance currents were obtained under high electric fields at various temperatures. The threshold derived from conduction current measurement decreases as temperature increases, which is similar with the space charge measurement. Due to the measurement accuracy and the interference of pulse source, the threshold of space charge is generally smaller than that of conductance current.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1 6","pages":"251-254"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91405900","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705473
N. Chalashkanov, Conor P. Clarke, S. Dodd
Partial discharge (PD) data obtained from electrical trees and void experiments were analyzed. Several correlations were identified between the various statistical parameters traditionally used in PD classification and deterministic features such as average power dissipation. The correlation coefficients were found to have very high values in the case of electrical trees. Numerical simulations of PD activity in tree structures and voids were then used to explain the origin of the observed dependencies. The correlations between the statistical parameters describing the PD data identified in this work, could potentially be used to improve the robustness and reliability of defect classification based on PD measurements.
{"title":"Statistical Features and Determinism in Partial Discharge Data from Electrical Trees and Voids","authors":"N. Chalashkanov, Conor P. Clarke, S. Dodd","doi":"10.1109/CEIDP50766.2021.9705473","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705473","url":null,"abstract":"Partial discharge (PD) data obtained from electrical trees and void experiments were analyzed. Several correlations were identified between the various statistical parameters traditionally used in PD classification and deterministic features such as average power dissipation. The correlation coefficients were found to have very high values in the case of electrical trees. Numerical simulations of PD activity in tree structures and voids were then used to explain the origin of the observed dependencies. The correlations between the statistical parameters describing the PD data identified in this work, could potentially be used to improve the robustness and reliability of defect classification based on PD measurements.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"36 1","pages":"598-602"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81374024","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705424
Hao Yang, Xuebao Li, Zhibin Zhao, Yuan Wang
In this paper, discharge pulses generated by surface discharge between the silicone gel and polyimide is studied under positive repetitive square voltage. The polarities of the discharge current pulses at the rising edge and falling edge are opposite, which are defined as the forward and backward discharge current pulses respectively in this paper. The peak values of discharge current pulses are extracted from the measured waveforms, the statistical results of discharge current pulses, discharge instantaneous voltage are analyzed in detail. The results show that the average instantaneous voltage of the forward discharge pulses occurring at the rising edge is higher than that of back discharge at the falling edge. Besides, the peak values of the discharge pulse increase with time at the beginning of the rising edge and the falling edge. As time goes by, the change of electric field generated by the surface charges will lead to an increase in dispersion of the peak values of discharge pulse. Finally, the discharge characteristics of surface characteristics are interpreted qualitatively.
{"title":"The Surface Discharge Characteristics of Interface between the Silicone Gel and Polyimide under Positive Repetitive Square Voltage","authors":"Hao Yang, Xuebao Li, Zhibin Zhao, Yuan Wang","doi":"10.1109/CEIDP50766.2021.9705424","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705424","url":null,"abstract":"In this paper, discharge pulses generated by surface discharge between the silicone gel and polyimide is studied under positive repetitive square voltage. The polarities of the discharge current pulses at the rising edge and falling edge are opposite, which are defined as the forward and backward discharge current pulses respectively in this paper. The peak values of discharge current pulses are extracted from the measured waveforms, the statistical results of discharge current pulses, discharge instantaneous voltage are analyzed in detail. The results show that the average instantaneous voltage of the forward discharge pulses occurring at the rising edge is higher than that of back discharge at the falling edge. Besides, the peak values of the discharge pulse increase with time at the beginning of the rising edge and the falling edge. As time goes by, the change of electric field generated by the surface charges will lead to an increase in dispersion of the peak values of discharge pulse. Finally, the discharge characteristics of surface characteristics are interpreted qualitatively.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"15 1","pages":"582-585"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80120150","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705456
M. Saleh, S. Refaat, M. Olesz, H. Abu-Rub
This work investigates the impact of an applied AC and DC high voltage on the electrical tree behavior in extruded cross-linked polyethylene (XLPE) insulation based on simulation and experimental validation. Extensive partial discharge (PD) testing methods are being implemented for high voltage cables under AC voltage for monitoring their condition. However, these PD testing methods cannot be utilized for power cables under DC voltages. DC voltages is considered in this study because of the rising implementation of HVDC cables worldwide. Therefore, it is of paramount importance to study the PD behavior originating from defects under DC voltages. Hence, classifying and diagnosing the defects taking place becomes crucial. In this paper, a 3D finite element analysis (FEA)-based modeling is considered to study the electrical treeing behavior using an embedded needle electrode in the XLPE insulation. The experiment entails PD tests with different applied high DC voltages (2.5, 5, 10, 11, and 12 kV) to study the impact on the initiation of PDs and ultimately tree growth. PD measurements were also investigated under AC voltages (7.1, 9.9, 11.3, 12.7, 14.1, and 17 kV) to compare them with PD results obtained with the applied DC voltage. The time-resolved partial discharge (TRPD) patterns are acquired for classifying the severity of the defect present in the XLPE insulation.
{"title":"Electrical Tree Growth Behavior Under AC and DC High Voltage in Power Cables","authors":"M. Saleh, S. Refaat, M. Olesz, H. Abu-Rub","doi":"10.1109/CEIDP50766.2021.9705456","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705456","url":null,"abstract":"This work investigates the impact of an applied AC and DC high voltage on the electrical tree behavior in extruded cross-linked polyethylene (XLPE) insulation based on simulation and experimental validation. Extensive partial discharge (PD) testing methods are being implemented for high voltage cables under AC voltage for monitoring their condition. However, these PD testing methods cannot be utilized for power cables under DC voltages. DC voltages is considered in this study because of the rising implementation of HVDC cables worldwide. Therefore, it is of paramount importance to study the PD behavior originating from defects under DC voltages. Hence, classifying and diagnosing the defects taking place becomes crucial. In this paper, a 3D finite element analysis (FEA)-based modeling is considered to study the electrical treeing behavior using an embedded needle electrode in the XLPE insulation. The experiment entails PD tests with different applied high DC voltages (2.5, 5, 10, 11, and 12 kV) to study the impact on the initiation of PDs and ultimately tree growth. PD measurements were also investigated under AC voltages (7.1, 9.9, 11.3, 12.7, 14.1, and 17 kV) to compare them with PD results obtained with the applied DC voltage. The time-resolved partial discharge (TRPD) patterns are acquired for classifying the severity of the defect present in the XLPE insulation.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"20 1","pages":"269-274"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82670970","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705316
S. Chaudhary, O. Vryonis, A. Vaughan, T. Andritsch
The molecular dynamics and physical mechanisms in dielectric nanocomposites are key to develop materials with tailored properties. The effect of the architecture of nanoparticles on the bulk properties is one such factor which needs to be studied and understood. The aim of this study is to investigate the effect of different core-shell structures on the bulk properties of the epoxy nanocomposites. TEM images confirm the successful synthesis of the core-shell and hollow nanoparticles. Epoxy nanocomposites filled with three types of nano-silica architectures, namely core (SiO2), core-shell (SiO2-SiO2) and hollow (h-SiO2) were prepared. They were characterised via broadband dielectric spectroscopy as a function of frequency in the range of 10−1-105 Hz and a temperature range of -160°C – 160°C. Besides well known relaxations, an additional so called SiOH relaxation is observed. Its intensity is proportional to the amorphous content of the nanoparticles. A distinct overlap between the epoxy β relaxation and SiOH relaxation is also observed, significantly affecting the intensity of the β relaxation. Finally, due to the presence of additional core-shell interface in case of SiO2-SiO2 filled nanocomposite two interfacial polarization peaks are observed. These preliminary findings illustrate noticeable effect of the architecture (additional interfacial polarization peak) and crystallinity (SiOH relaxation) of the nanoparticles on the dielectric behaviour of the nanocomposite.
{"title":"Dielectric Response in Epoxy Nanocomposites Incorporating Various Nano-silica Architectures","authors":"S. Chaudhary, O. Vryonis, A. Vaughan, T. Andritsch","doi":"10.1109/CEIDP50766.2021.9705316","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705316","url":null,"abstract":"The molecular dynamics and physical mechanisms in dielectric nanocomposites are key to develop materials with tailored properties. The effect of the architecture of nanoparticles on the bulk properties is one such factor which needs to be studied and understood. The aim of this study is to investigate the effect of different core-shell structures on the bulk properties of the epoxy nanocomposites. TEM images confirm the successful synthesis of the core-shell and hollow nanoparticles. Epoxy nanocomposites filled with three types of nano-silica architectures, namely core (SiO2), core-shell (SiO2-SiO2) and hollow (h-SiO2) were prepared. They were characterised via broadband dielectric spectroscopy as a function of frequency in the range of 10−1-105 Hz and a temperature range of -160°C – 160°C. Besides well known relaxations, an additional so called SiOH relaxation is observed. Its intensity is proportional to the amorphous content of the nanoparticles. A distinct overlap between the epoxy β relaxation and SiOH relaxation is also observed, significantly affecting the intensity of the β relaxation. Finally, due to the presence of additional core-shell interface in case of SiO2-SiO2 filled nanocomposite two interfacial polarization peaks are observed. These preliminary findings illustrate noticeable effect of the architecture (additional interfacial polarization peak) and crystallinity (SiOH relaxation) of the nanoparticles on the dielectric behaviour of the nanocomposite.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"R-30 1","pages":"57-60"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84754631","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705472
R. Gerlach, Diego Machetti, Martin Willems, R. Puffer
Deformations of magnetic cores of inductive medium-voltage instrument transformers can lead to measurement errors and therefore require elastic compensation layers. These deformations occur due to manufacturing-related mechanical stresses of epoxy resin-based insulating systems. Alternatively, compressible gas-filled polymer hollow microspheres can be embedded in the epoxy resin matrix to increase elasticity. By using this composite material known as syntactic foam, costly cushioning layers can be avoided. However, current laboratory-scale manufacturing processes require of a complex mold rotation to prevent sedimentation of the hollow microspheres in the cured material. In order to make syntactic foam more accessible for industrial applications, the effect of a thixotropic agent to homogenize the distribution of hollow microspheres was investigated. Specimens using both manufacturing processes (mold rotation and thixotropic agent) with varying filling degrees were prepared and compared on the basis of their hollow microspheres’ distribution and dielectric properties. Given the minor differences of measurement results and the simplified manufacturing process, the use of thixotropic agents for avoiding sedimentation in epoxy resin-based syntactic foams is recommended.
{"title":"On the Effect of a Thixotropic Agent on the Dielectric Properties of Epoxy Resin-based Syntactic Foams","authors":"R. Gerlach, Diego Machetti, Martin Willems, R. Puffer","doi":"10.1109/CEIDP50766.2021.9705472","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705472","url":null,"abstract":"Deformations of magnetic cores of inductive medium-voltage instrument transformers can lead to measurement errors and therefore require elastic compensation layers. These deformations occur due to manufacturing-related mechanical stresses of epoxy resin-based insulating systems. Alternatively, compressible gas-filled polymer hollow microspheres can be embedded in the epoxy resin matrix to increase elasticity. By using this composite material known as syntactic foam, costly cushioning layers can be avoided. However, current laboratory-scale manufacturing processes require of a complex mold rotation to prevent sedimentation of the hollow microspheres in the cured material. In order to make syntactic foam more accessible for industrial applications, the effect of a thixotropic agent to homogenize the distribution of hollow microspheres was investigated. Specimens using both manufacturing processes (mold rotation and thixotropic agent) with varying filling degrees were prepared and compared on the basis of their hollow microspheres’ distribution and dielectric properties. Given the minor differences of measurement results and the simplified manufacturing process, the use of thixotropic agents for avoiding sedimentation in epoxy resin-based syntactic foams is recommended.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"8 1","pages":"9-12"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84789561","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705476
Y. Ohki, Hao-Long Zhou, N. Hirai
Flame-retardant cross-linked polyolefin (FR-XLPO) is important insulating material for electric cables in nuclear power plants. Safety-related cables in a nuclear power plant must withstand high temperature and radiation during the normal operation and additional concurrent high-temperature steam and high-dose-rate radiation when an accident occurs. In this study, the degradation behavior of FR-XLPO under simulated accident conditions was investigated. As a result, it has become clear that FR-XLPO is resistant to gamma rays and superheated steam, especially in the absence of oxygen.
{"title":"Degradation of Flame-retardant Cross-linked Polyolefin Caused by Severe Aging Treatments","authors":"Y. Ohki, Hao-Long Zhou, N. Hirai","doi":"10.1109/CEIDP50766.2021.9705476","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705476","url":null,"abstract":"Flame-retardant cross-linked polyolefin (FR-XLPO) is important insulating material for electric cables in nuclear power plants. Safety-related cables in a nuclear power plant must withstand high temperature and radiation during the normal operation and additional concurrent high-temperature steam and high-dose-rate radiation when an accident occurs. In this study, the degradation behavior of FR-XLPO under simulated accident conditions was investigated. As a result, it has become clear that FR-XLPO is resistant to gamma rays and superheated steam, especially in the absence of oxygen.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1 1","pages":"89-92"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83060132","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705442
Mychal P. Spencer, L. Fifield
Wave energy converter (WEC) systems have unique umbilical cable design requirements compared to conventional marine designs. Due to their dynamic nature, WEC umbilical cables are required to handle increased loads and larger motions over longer deployment scenarios. However, the life expectancy of dynamic umbilical cables is predominantly analyzed for mechanical fatigue, with little consideration given to the effect of mechanical stress on the response of the dielectric as it has been previously assumed that the non-polymeric components will fail prior to the polymeric components. In this work, we explore the effects of mechanical bending on the concentration of the electric field in the insulation of a conceptual three-core dynamic umbilical cable to determine the limiting requirements for life expectancy. A conceptual industrial schematic of a medium voltage dynamic umbilical cable was used as the basis for the WEC system under study. Simulations on the dynamic umbilical cable were performed using COMSOL Multiphysics®. Mechanical loads up to the calculated limit (2.64 m minimum bend radius or 388 kN transverse load) were applied to the dynamic umbilical in a step-wise fashion with one end of the umbilical cable fixed. One-way coupling in three-dimensions was conducted by first determining the engineering strains, then using the engineering strains as the initial condition for determination of the Green-Lagrange strains, and lastly calculating the electric field in the deformed dielectric. Based upon the input load, deformation of the dielectric at the minimum bend radius produced an increase in the electric field of more than 12% when compared to the undeformed umbilical cable, which may lead to dielectric breakdown of the insulation prior to mechanical failure of the umbilical cable.
{"title":"Effect of Mechanical Deformation on the Dielectric Electric Field in Dynamic Umbilical Cables","authors":"Mychal P. Spencer, L. Fifield","doi":"10.1109/CEIDP50766.2021.9705442","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705442","url":null,"abstract":"Wave energy converter (WEC) systems have unique umbilical cable design requirements compared to conventional marine designs. Due to their dynamic nature, WEC umbilical cables are required to handle increased loads and larger motions over longer deployment scenarios. However, the life expectancy of dynamic umbilical cables is predominantly analyzed for mechanical fatigue, with little consideration given to the effect of mechanical stress on the response of the dielectric as it has been previously assumed that the non-polymeric components will fail prior to the polymeric components. In this work, we explore the effects of mechanical bending on the concentration of the electric field in the insulation of a conceptual three-core dynamic umbilical cable to determine the limiting requirements for life expectancy. A conceptual industrial schematic of a medium voltage dynamic umbilical cable was used as the basis for the WEC system under study. Simulations on the dynamic umbilical cable were performed using COMSOL Multiphysics®. Mechanical loads up to the calculated limit (2.64 m minimum bend radius or 388 kN transverse load) were applied to the dynamic umbilical in a step-wise fashion with one end of the umbilical cable fixed. One-way coupling in three-dimensions was conducted by first determining the engineering strains, then using the engineering strains as the initial condition for determination of the Green-Lagrange strains, and lastly calculating the electric field in the deformed dielectric. Based upon the input load, deformation of the dielectric at the minimum bend radius produced an increase in the electric field of more than 12% when compared to the undeformed umbilical cable, which may lead to dielectric breakdown of the insulation prior to mechanical failure of the umbilical cable.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"84 1","pages":"651-654"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83140968","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705363
N. Guerrini, G. Mazzanti, B. Diban, I. Troia
The operational constraints for the supply and exercise of HV extruded cable systems requires a fast and reliable localization of possible faults in cable insulation. Methods are available in the literature for offline fault location for both underground and (long) submarine cables installed in the field. The main method used is Time Domain Reflectometry (TDR), which works well when the fault impedance is low, but other methods are also available for relatively high fault impedances. However, such methods require a subsequent fault pin-pointing that works well offline and in the field. On the other side, there is the need of an effective and extremely-accurate localization method that can be applied on factory tests as well as on site. The purpose of this work is to get insights on such effective online fault localization technique in factory-tested cables, based on the analysis of the fault curve and on its comparison to different offline fault localization methods.
{"title":"Investigation on Online Fault Location Techniques During Factory Testing on Manufactured Cable Lengths","authors":"N. Guerrini, G. Mazzanti, B. Diban, I. Troia","doi":"10.1109/CEIDP50766.2021.9705363","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705363","url":null,"abstract":"The operational constraints for the supply and exercise of HV extruded cable systems requires a fast and reliable localization of possible faults in cable insulation. Methods are available in the literature for offline fault location for both underground and (long) submarine cables installed in the field. The main method used is Time Domain Reflectometry (TDR), which works well when the fault impedance is low, but other methods are also available for relatively high fault impedances. However, such methods require a subsequent fault pin-pointing that works well offline and in the field. On the other side, there is the need of an effective and extremely-accurate localization method that can be applied on factory tests as well as on site. The purpose of this work is to get insights on such effective online fault localization technique in factory-tested cables, based on the analysis of the fault curve and on its comparison to different offline fault localization methods.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"61 Suppl 1","pages":"619-622"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91372522","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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