Pub Date : 2020-06-01DOI: 10.1109/eic47619.2020.9158739
A. Caprara, G. Ciotti, L. Paschini
Power utilities are lately investing in asset management systems and tools that provide them with analytical parameters from field data to properly evaluate the conditions of their electrical assets, in particular the ones connected into the generation and transmission networks. Any fault leading to an outage could result in huge monetary losses related not only to repair costs but also to lack of energy generation or availability. This is particularly true in the case of electrical assets such as power generators like the one hereafter described and analyzed. One of the tools available for the asset managers to perform such evaluation is the on-line monitoring of the Partial Discharge (PD) phenomena, a non-intrusive technique capable of evaluating in real-time the conditions of the electrical insulation system, commonly considered the weakest point of most electrical assets and the principal source of faults leading to electrical outages. In this paper, an example of the effectiveness in the usage of such technique is discussed about a 30 MVA synchronous generator. Data related to the PD phenomena detected in the insulation system are reported together with the relevant analysis and their behavior over monitoring sessions. Moreover, since during the monitoring period some maintenance actions have been carried out by the utility owning the power station, the relation with the detected PD phenomena will be shown and discussed. This allows performing some critical evaluation about the effectiveness of the maintenance actions carried out.
{"title":"Analysis of the results of on-line Partial Discharge Monitoring and the impact of the maintenance actions on a 30 MVA synchronous generator","authors":"A. Caprara, G. Ciotti, L. Paschini","doi":"10.1109/eic47619.2020.9158739","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158739","url":null,"abstract":"Power utilities are lately investing in asset management systems and tools that provide them with analytical parameters from field data to properly evaluate the conditions of their electrical assets, in particular the ones connected into the generation and transmission networks. Any fault leading to an outage could result in huge monetary losses related not only to repair costs but also to lack of energy generation or availability. This is particularly true in the case of electrical assets such as power generators like the one hereafter described and analyzed. One of the tools available for the asset managers to perform such evaluation is the on-line monitoring of the Partial Discharge (PD) phenomena, a non-intrusive technique capable of evaluating in real-time the conditions of the electrical insulation system, commonly considered the weakest point of most electrical assets and the principal source of faults leading to electrical outages. In this paper, an example of the effectiveness in the usage of such technique is discussed about a 30 MVA synchronous generator. Data related to the PD phenomena detected in the insulation system are reported together with the relevant analysis and their behavior over monitoring sessions. Moreover, since during the monitoring period some maintenance actions have been carried out by the utility owning the power station, the relation with the detected PD phenomena will be shown and discussed. This allows performing some critical evaluation about the effectiveness of the maintenance actions carried out.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114487144","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 : 2020-06-01DOI: 10.1109/EIC47619.2020.9158587
Yi Ma, Guochao Qian, Hongming Ma, Wei Wang, Dingkai Xu, Zhongzheng Ning
The circuit breaker opening test needs to be carried out under conditions of both high voltage and high current. The traditional method is to use the synthetic loop method, which requires a very large capacity power supply, and the cost of the test is very high too. in this paper, a simulation method based on the damped oscillating voltage circuit breaker for high current breaking process is introduced. A simulation platform including DC power, light-controlled thyristor switches, reactors and capacitors was established. Through the cooperation of the capacitor and the reactor, the oscillation frequency of 50 Hz is obtained. Under the voltage of 40 kV, the amplitude of the oscillating current exceeds 100 A, and the duration exceeds 100ms. The breaking process of the circuit breaker generally does not exceed 100ms, which indicates that the method proposed in this paper can fully meet the requirements of the circuit breaker breaking simulation test. Finally, experimental verification was conducted on the established platform.
{"title":"Simulation method for large current opening process of circuit breaker based on damped oscillating voltage","authors":"Yi Ma, Guochao Qian, Hongming Ma, Wei Wang, Dingkai Xu, Zhongzheng Ning","doi":"10.1109/EIC47619.2020.9158587","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158587","url":null,"abstract":"The circuit breaker opening test needs to be carried out under conditions of both high voltage and high current. The traditional method is to use the synthetic loop method, which requires a very large capacity power supply, and the cost of the test is very high too. in this paper, a simulation method based on the damped oscillating voltage circuit breaker for high current breaking process is introduced. A simulation platform including DC power, light-controlled thyristor switches, reactors and capacitors was established. Through the cooperation of the capacitor and the reactor, the oscillation frequency of 50 Hz is obtained. Under the voltage of 40 kV, the amplitude of the oscillating current exceeds 100 A, and the duration exceeds 100ms. The breaking process of the circuit breaker generally does not exceed 100ms, which indicates that the method proposed in this paper can fully meet the requirements of the circuit breaker breaking simulation test. Finally, experimental verification was conducted on the established platform.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117022914","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158670
Chunmeng Xu, Jia Wei, L. Graber
The compatibility of a multilayer piezoelectric actuator operating in supercritical carbon dioxide was tested using a voltage-based self-sensing technique. The phase transitions of carbon dioxide to supercritical state were recorded visually. No degradation was observed in leakage current of the piezoelectric actuator after being immersed in supercritical carbon dioxide for hours. This confirmed compatibility allows further applications of supercritical carbon dioxide as the insulating medium in power equipment, like a fast mechanical switch for hybrid direct current circuit breakers in medium voltage direct current power systems.
{"title":"Compatibility Analysis of Piezoelectric Actuators in Supercritical Carbon Dioxide","authors":"Chunmeng Xu, Jia Wei, L. Graber","doi":"10.1109/eic47619.2020.9158670","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158670","url":null,"abstract":"The compatibility of a multilayer piezoelectric actuator operating in supercritical carbon dioxide was tested using a voltage-based self-sensing technique. The phase transitions of carbon dioxide to supercritical state were recorded visually. No degradation was observed in leakage current of the piezoelectric actuator after being immersed in supercritical carbon dioxide for hours. This confirmed compatibility allows further applications of supercritical carbon dioxide as the insulating medium in power equipment, like a fast mechanical switch for hybrid direct current circuit breakers in medium voltage direct current power systems.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115869758","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 : 2020-06-01DOI: 10.1109/EIC47619.2020.9158714
M. Meira, R. Álvarez, C. Verucchi, Leonardo J. Catalano, C. Ruschetti
Dielectric oil is part of the power transformer insulation system. There it performs its dual functions of providing cooling and insulation within the transformer. In recent years there has been a resurgence in the use of natural esters (vegetable oils), driven by environmental concerns. In this sense, their biodegradable characteristics and high flash point compared to mineral oils increase their use. However, their limited knowledge of long-term performance in service compared to mineral oil limits their application in power transformers. For these reasons, it is necessary to compare mineral oils and natural esters under different stresses. This work presents a comparison of the performance and behavior of an insulation system impregnated with mineral oil with another impregnated with natural ester under identical thermal stress. Physicochemical parameters, degree of polymerization, dielectric frequency response and gas generation are evaluated and analyzed. As a variant in the models to be analyzed, windings with different geometries were used. It was concluded that the paper impregnated with natural ester has practically not changed its moisture content with the aging time. Paper in cells with natural ester has aged somewhat less, although at low load temperatures the aging may be similar. It has been shown that the temperature reached in the windings is dependent in part on the geometry.
{"title":"Thermal aging analysis of mineral oil and natural ester immersed windings","authors":"M. Meira, R. Álvarez, C. Verucchi, Leonardo J. Catalano, C. Ruschetti","doi":"10.1109/EIC47619.2020.9158714","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158714","url":null,"abstract":"Dielectric oil is part of the power transformer insulation system. There it performs its dual functions of providing cooling and insulation within the transformer. In recent years there has been a resurgence in the use of natural esters (vegetable oils), driven by environmental concerns. In this sense, their biodegradable characteristics and high flash point compared to mineral oils increase their use. However, their limited knowledge of long-term performance in service compared to mineral oil limits their application in power transformers. For these reasons, it is necessary to compare mineral oils and natural esters under different stresses. This work presents a comparison of the performance and behavior of an insulation system impregnated with mineral oil with another impregnated with natural ester under identical thermal stress. Physicochemical parameters, degree of polymerization, dielectric frequency response and gas generation are evaluated and analyzed. As a variant in the models to be analyzed, windings with different geometries were used. It was concluded that the paper impregnated with natural ester has practically not changed its moisture content with the aging time. Paper in cells with natural ester has aged somewhat less, although at low load temperatures the aging may be similar. It has been shown that the temperature reached in the windings is dependent in part on the geometry.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127876777","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158660
G. Montanari, L. Cirioni, G. Galvagno, S. Mastroeni
The performance of a new idea of sensor for detecting partial discharge in switchboards is developed in this paper. A capacitive divider embedded in switchboard bushing is tested using two types of voltage impulse sources, that is, a calibrator and an object generating internal partial discharges (the latter is chosen based on the consideration that partial discharges from internal cavities are the most harmful phenomenon affecting insulation life). It is shown that the sensor embedded in a switchboard bushing has very good sensitivity to defects located inside the switchboard and also at the switchboard cable terminal, and much less sensitivity, compared to a HFCT, to disturbances coming from the electrical circuit connected to the switchboard. This would favor both partial discharge identification and their location, enabling effective diagnosis and alerting.
{"title":"Partial Discharges testing in MV switchboards: sensitivity evaluation of embedded sensors","authors":"G. Montanari, L. Cirioni, G. Galvagno, S. Mastroeni","doi":"10.1109/eic47619.2020.9158660","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158660","url":null,"abstract":"The performance of a new idea of sensor for detecting partial discharge in switchboards is developed in this paper. A capacitive divider embedded in switchboard bushing is tested using two types of voltage impulse sources, that is, a calibrator and an object generating internal partial discharges (the latter is chosen based on the consideration that partial discharges from internal cavities are the most harmful phenomenon affecting insulation life). It is shown that the sensor embedded in a switchboard bushing has very good sensitivity to defects located inside the switchboard and also at the switchboard cable terminal, and much less sensitivity, compared to a HFCT, to disturbances coming from the electrical circuit connected to the switchboard. This would favor both partial discharge identification and their location, enabling effective diagnosis and alerting.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127414166","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158710
W. McDermid
Over the years novel designs have been implemented which provide considerable cost savings over conventional designs. The paper provides examples associated with rotating machines, instrument transformers, bushings, surge arresters, and distribution class pin insulators. In all cases cited in-service failures have resulted.
{"title":"Not So Bright Ideas","authors":"W. McDermid","doi":"10.1109/eic47619.2020.9158710","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158710","url":null,"abstract":"Over the years novel designs have been implemented which provide considerable cost savings over conventional designs. The paper provides examples associated with rotating machines, instrument transformers, bushings, surge arresters, and distribution class pin insulators. In all cases cited in-service failures have resulted.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122343022","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158577
R. Kuppuswamy
Online partial discharge (PD) measurements have long been used as an effective means to evaluate the condition of the stator windings of generators and motors. Those who manage a fleet of such assets have the responsibility to minimize the risk of disruption in service. The efficient way of managing is to allocate maintenance funds only to the asset(s) that needs immediate attention and to delay or skip maintenance for the rest in the population. The common practice to shortlist the worst performing assets is to use preset criteria based on PD pulse magnitude, its repetition rate or its derivatives. These metrics are unreliable as PD activity inside electrical insulation can accelerate or decelerate without a change in the physical condition of the electric insulation. Using them to shortlist the worst performing assets often results in incorrect identification and wastage of time and resources investigating the wrong bunch. Therefore, a better method to identify and profile the maintenance needs of an asset is needed. In the paper, a method to identify the worst performing assets in a fleet and determine if maintenance action is needed using PD measurement data is described. The fleet screening tool is based on the estimation of a sampling of destructive energy absorbed by the electrical insulation from PD activity and comparing its longterm accumulated values against a base distribution which is effectively a historical database of annual averages of actual power dissipated by a large population of similar assets. This tool provides a quick and usable result: what percent of similar assets in the population have suffered more damage than any given asset. This allows the asset owner to prioritize the asset for maintenance and minimize the risk of disruption in service. An example of the implementation is illustrated.
{"title":"Method to Profile the Maintenance Needs of a Fleet of Rotating Machine Assets using Partial Discharge Data","authors":"R. Kuppuswamy","doi":"10.1109/eic47619.2020.9158577","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158577","url":null,"abstract":"Online partial discharge (PD) measurements have long been used as an effective means to evaluate the condition of the stator windings of generators and motors. Those who manage a fleet of such assets have the responsibility to minimize the risk of disruption in service. The efficient way of managing is to allocate maintenance funds only to the asset(s) that needs immediate attention and to delay or skip maintenance for the rest in the population. The common practice to shortlist the worst performing assets is to use preset criteria based on PD pulse magnitude, its repetition rate or its derivatives. These metrics are unreliable as PD activity inside electrical insulation can accelerate or decelerate without a change in the physical condition of the electric insulation. Using them to shortlist the worst performing assets often results in incorrect identification and wastage of time and resources investigating the wrong bunch. Therefore, a better method to identify and profile the maintenance needs of an asset is needed. In the paper, a method to identify the worst performing assets in a fleet and determine if maintenance action is needed using PD measurement data is described. The fleet screening tool is based on the estimation of a sampling of destructive energy absorbed by the electrical insulation from PD activity and comparing its longterm accumulated values against a base distribution which is effectively a historical database of annual averages of actual power dissipated by a large population of similar assets. This tool provides a quick and usable result: what percent of similar assets in the population have suffered more damage than any given asset. This allows the asset owner to prioritize the asset for maintenance and minimize the risk of disruption in service. An example of the implementation is illustrated.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127043523","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 : 2020-06-01DOI: 10.1109/EIC47619.2020.9158748
F. Haque, Jia Wei, L. Graber, Chanyeop Park
Density fluctuations caused by clustering occurs during phase transition near the critical point, beyond which is the supercritical phase. Supercritical phase is the intermediate state where fluids show both liquid and gas properties. The high dielectric strength provided by the high density of supercritical fluid exhibits a steep degradation at the phase change due to the so-called clustering effect. In this paper, the dielectric properties of SC CO2 have been studied. Based on the dielectric strength analysis method used for gas mixtures, the electron-scattering cross section data of SCF CO2 clusters is utilized, which are modified from those of gaseous CO2 assuming various cluster sizes, to estimate the density-fluctuation-dependent dielectric strength of SCF CO2. The electron energy loss models of distinct electron energy levels have been utilized to determine the geometrical electron scattering cross section data of SCF CO2 clusters with various cluster sizes and impinging electron energies.
{"title":"Electron Scattering Cross Section Data of Supercritical CO2 Clusters","authors":"F. Haque, Jia Wei, L. Graber, Chanyeop Park","doi":"10.1109/EIC47619.2020.9158748","DOIUrl":"https://doi.org/10.1109/EIC47619.2020.9158748","url":null,"abstract":"Density fluctuations caused by clustering occurs during phase transition near the critical point, beyond which is the supercritical phase. Supercritical phase is the intermediate state where fluids show both liquid and gas properties. The high dielectric strength provided by the high density of supercritical fluid exhibits a steep degradation at the phase change due to the so-called clustering effect. In this paper, the dielectric properties of SC CO2 have been studied. Based on the dielectric strength analysis method used for gas mixtures, the electron-scattering cross section data of SCF CO2 clusters is utilized, which are modified from those of gaseous CO2 assuming various cluster sizes, to estimate the density-fluctuation-dependent dielectric strength of SCF CO2. The electron energy loss models of distinct electron energy levels have been utilized to determine the geometrical electron scattering cross section data of SCF CO2 clusters with various cluster sizes and impinging electron energies.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129544666","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158762
D. Robalino, Ismail Güner
HV and EHV systems operate in a reliable and safe manner thanks to a proactive operational strategy and qualified expert judgement taken by asset management specialists and equipment manufacturers. Nevertheless, failure during operation is a potential risk that may derive in catastrophic events. In the field, there is a large amount of HV and EHV equipment such as bushings and instrument transformers with paper and mineral oil as main insulation media. For these equipment, oil sampling might be an option but it is not desirable, and sometimes, not even recommended by manufacturers. Aiming to avoid any catastrophic event, Hydro Quebec has relied on a variety of testing techniques to evaluate the condition of instrument transformers and bushings. Hydro Quebec incorporated dielectric frequency response (DFR) for condition assessment of oil-paper and resin-paper insulation systems. Technology now is not limited to low voltage DFR but it incorporates high voltage DFR (HVDFR) and the individual temperature correction (ITC) algorithm which have opened the opportunity for qualitative and quantitative evaluation. HV DFR and ITC present an alternative to intrusive diagnostic techniques for condition assessment and failure analysis of the main insulation of HV and EHV bushings and instrument transformers. The dielectric responses obtained from “normally aged” and “faulty” HV and EHV Current Transformers (CT) are discussed throughout this document, in addition with the analysis of the ITC algorithm as applied to MV, HV and EHV OIP CTs. The work covers a 765 kV rated OIP type CT removed from service and fully dissected to correlate DGA, DFR and actual findings inside the insulation system of the CT.
{"title":"Investigation of EHV Current Transformer Failure by Dielectric Frequency Response Technique","authors":"D. Robalino, Ismail Güner","doi":"10.1109/eic47619.2020.9158762","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158762","url":null,"abstract":"HV and EHV systems operate in a reliable and safe manner thanks to a proactive operational strategy and qualified expert judgement taken by asset management specialists and equipment manufacturers. Nevertheless, failure during operation is a potential risk that may derive in catastrophic events. In the field, there is a large amount of HV and EHV equipment such as bushings and instrument transformers with paper and mineral oil as main insulation media. For these equipment, oil sampling might be an option but it is not desirable, and sometimes, not even recommended by manufacturers. Aiming to avoid any catastrophic event, Hydro Quebec has relied on a variety of testing techniques to evaluate the condition of instrument transformers and bushings. Hydro Quebec incorporated dielectric frequency response (DFR) for condition assessment of oil-paper and resin-paper insulation systems. Technology now is not limited to low voltage DFR but it incorporates high voltage DFR (HVDFR) and the individual temperature correction (ITC) algorithm which have opened the opportunity for qualitative and quantitative evaluation. HV DFR and ITC present an alternative to intrusive diagnostic techniques for condition assessment and failure analysis of the main insulation of HV and EHV bushings and instrument transformers. The dielectric responses obtained from “normally aged” and “faulty” HV and EHV Current Transformers (CT) are discussed throughout this document, in addition with the analysis of the ITC algorithm as applied to MV, HV and EHV OIP CTs. The work covers a 765 kV rated OIP type CT removed from service and fully dissected to correlate DGA, DFR and actual findings inside the insulation system of the CT.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130538468","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 : 2020-06-01DOI: 10.1109/eic47619.2020.9158709
A. Gorji, S. Banerjee, S. Jayaram
In this work, a systematic study of the dielectric spectra of full-scale medium-voltage (MV) ethylene propylene rubber- (EPR) and tree-retardant cross-linked polyethylene-(TR-XLPE) insulated cables is presented within the frequency range from 10−1 Hz to 106 Hz at various temperatures from 25 °C to 80 °C. The measured spectra were fitted using Havriliak- Negami (HN) model to find potential indicators of temperature variation. Results show that a complete modeling of MV cable section requires understanding of dielectric properties of insulator layers as well as distinct behavior of semi-conductive layers, particularly at frequencies above 106 Hz.
{"title":"Dielectric Characterization Study on Medium-Voltage Ethylene Propylene Rubber (EPR) and Tree-Retardant Cross-Linked Polyethylene (TR-XLPE) Cables under Varying Thermal Conditions","authors":"A. Gorji, S. Banerjee, S. Jayaram","doi":"10.1109/eic47619.2020.9158709","DOIUrl":"https://doi.org/10.1109/eic47619.2020.9158709","url":null,"abstract":"In this work, a systematic study of the dielectric spectra of full-scale medium-voltage (MV) ethylene propylene rubber- (EPR) and tree-retardant cross-linked polyethylene-(TR-XLPE) insulated cables is presented within the frequency range from 10−1 Hz to 106 Hz at various temperatures from 25 °C to 80 °C. The measured spectra were fitted using Havriliak- Negami (HN) model to find potential indicators of temperature variation. Results show that a complete modeling of MV cable section requires understanding of dielectric properties of insulator layers as well as distinct behavior of semi-conductive layers, particularly at frequencies above 106 Hz.","PeriodicalId":286019,"journal":{"name":"2020 IEEE Electrical Insulation Conference (EIC)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132249757","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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