Pub Date : 2012-11-26DOI: 10.1109/ICHVE.2012.6357065
Chaoliang Qi, Lijun Yang, Wei Li, J. Hao, Zhiqin Ma, Jinjun Bai
Frequency domain dielectric spectroscopy (FDS) based on dielectric response has been widely used for assessment the state of oil-paper insulation in transformers. However, domestic and foreign researches are mostly focused on qualitative analyzing the changing behavior of frequency domain spectrum curve for different insulation conditions, such as different temperature, moisture and aging status. It is difficult to find a method to extract the frequency-domain characteristic parameters that can be effectively quantified the state of oil-paper insulation. Thus no quantify analyzing the frequency-domain spectrum curve has been made at present. In this paper, firstly, the basic theory of dielectric polarization and a new Cole-Cole model with four polarization processes were introduced. Secondly, FDS measurements on oil impregnated insulation paper at different temperatures were made. Finally, new frequency-domain characteristic parameters for FDS curves were extracted using the new Cole-Cole model. In this way, the physical polarization process could be also clearly understood.
{"title":"Extraction method for frequency domain characteristic parameters of oil impregnated insulation paper","authors":"Chaoliang Qi, Lijun Yang, Wei Li, J. Hao, Zhiqin Ma, Jinjun Bai","doi":"10.1109/ICHVE.2012.6357065","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357065","url":null,"abstract":"Frequency domain dielectric spectroscopy (FDS) based on dielectric response has been widely used for assessment the state of oil-paper insulation in transformers. However, domestic and foreign researches are mostly focused on qualitative analyzing the changing behavior of frequency domain spectrum curve for different insulation conditions, such as different temperature, moisture and aging status. It is difficult to find a method to extract the frequency-domain characteristic parameters that can be effectively quantified the state of oil-paper insulation. Thus no quantify analyzing the frequency-domain spectrum curve has been made at present. In this paper, firstly, the basic theory of dielectric polarization and a new Cole-Cole model with four polarization processes were introduced. Secondly, FDS measurements on oil impregnated insulation paper at different temperatures were made. Finally, new frequency-domain characteristic parameters for FDS curves were extracted using the new Cole-Cole model. In this way, the physical polarization process could be also clearly understood.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"37 1","pages":"110-114"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80178060","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357014
Ling Zhang, Yifeng Li, C. Yao, Y. Mi, Y. Long
The measurement of lightning current is essential to lightning protection in grid, because only if accurate amplitude and waveform of the lightning current is obtained can the correct lightning protection measures be taken. However, in a high voltage power system, it is almost impossible to measure directly the lightning currents accurately and safely. So aiming at solving the problem of accurate and safe measurement of the lightning current on the overhead transmission lines, the differential loop which has been widely used in the pulse power measurement technique is applied, and a new method of measurement which based on the principle of differential loop can measure the lightning current on overhead transmission lines contactless is used and improved considering the actual running conditions in the 110kV level of transmission line. In this essay, the principle of differential loop for measuring lightning current and the design of the detector are introduced. In laboratory by using the high impulse current generator to simulate the lightning currents, the experiment results show that: for the 1.4m measurement distance, through selecting appropriate size of differential loop and the number of turns, and choosing reasonable shielding, combined with self-integral, the measurement sensor can reflect the waveform and the amplitude of the currents which is produced by the high impulse current generator accurately, and has the advantage of safety, strong anti-interference, well linearity and accuracy.
{"title":"Lightning current measurement by differential loop for 110kV transmission line","authors":"Ling Zhang, Yifeng Li, C. Yao, Y. Mi, Y. Long","doi":"10.1109/ICHVE.2012.6357014","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357014","url":null,"abstract":"The measurement of lightning current is essential to lightning protection in grid, because only if accurate amplitude and waveform of the lightning current is obtained can the correct lightning protection measures be taken. However, in a high voltage power system, it is almost impossible to measure directly the lightning currents accurately and safely. So aiming at solving the problem of accurate and safe measurement of the lightning current on the overhead transmission lines, the differential loop which has been widely used in the pulse power measurement technique is applied, and a new method of measurement which based on the principle of differential loop can measure the lightning current on overhead transmission lines contactless is used and improved considering the actual running conditions in the 110kV level of transmission line. In this essay, the principle of differential loop for measuring lightning current and the design of the detector are introduced. In laboratory by using the high impulse current generator to simulate the lightning currents, the experiment results show that: for the 1.4m measurement distance, through selecting appropriate size of differential loop and the number of turns, and choosing reasonable shielding, combined with self-integral, the measurement sensor can reflect the waveform and the amplitude of the currents which is produced by the high impulse current generator accurately, and has the advantage of safety, strong anti-interference, well linearity and accuracy.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"29 1","pages":"133-136"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80496108","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357073
Shengke Chen, Caipeng Yue, Wei Wang, D. He, Kai Yang
Traditionally, oil-filled transformers have utilized cellulose paper as primary insulation. However, cellulose insulation is a relatively low temperature material and thermal degradation due to overload conditions and long-term aging can lead to transformer failures, Therefore, it restraints the development of high density power transformers. What's more, since the transformer oil has a relative dielectric constant of 2.2, a material with a high dielectric constant can increase the stress in the oil and cause a breakdown in the transformer. In an effort to find a more suitable insulating material than the cellulose paper for use in an oil-filled transformer, on the basis of fundamental properties of polymer materials, we choose 4 polymer materials with low permittivity and dielectric loss, high electric strength, partial discharge inception voltage and insulation resistance, including polyphenylene sulfide (PPS), polycarbonate (PC), Polytetrafluoroethylene (PTFE) and polyester film (PET). In our experiment, the kraft paper, PC, PET, PPS, PTFE with 0.5mm thick are used. The kraft paper and these four polymer materials are aged in mineral oil for a period of 270 days under 90°C, 110°C and 130°C respectively, simultaneously an electric pre-stressing of 4kV/mm is performed, Then analyze the SEM, the PD inception voltage and volume resistivity of the kraft paper and four polymer materials before and after electro-thermal aging.
{"title":"Volume resistivity and PDIV characteristics of polymer materials under electro-thermal aging","authors":"Shengke Chen, Caipeng Yue, Wei Wang, D. He, Kai Yang","doi":"10.1109/ICHVE.2012.6357073","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357073","url":null,"abstract":"Traditionally, oil-filled transformers have utilized cellulose paper as primary insulation. However, cellulose insulation is a relatively low temperature material and thermal degradation due to overload conditions and long-term aging can lead to transformer failures, Therefore, it restraints the development of high density power transformers. What's more, since the transformer oil has a relative dielectric constant of 2.2, a material with a high dielectric constant can increase the stress in the oil and cause a breakdown in the transformer. In an effort to find a more suitable insulating material than the cellulose paper for use in an oil-filled transformer, on the basis of fundamental properties of polymer materials, we choose 4 polymer materials with low permittivity and dielectric loss, high electric strength, partial discharge inception voltage and insulation resistance, including polyphenylene sulfide (PPS), polycarbonate (PC), Polytetrafluoroethylene (PTFE) and polyester film (PET). In our experiment, the kraft paper, PC, PET, PPS, PTFE with 0.5mm thick are used. The kraft paper and these four polymer materials are aged in mineral oil for a period of 270 days under 90°C, 110°C and 130°C respectively, simultaneously an electric pre-stressing of 4kV/mm is performed, Then analyze the SEM, the PD inception voltage and volume resistivity of the kraft paper and four polymer materials before and after electro-thermal aging.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"49 1","pages":"190-193"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80610113","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357005
C. Kocatepe, O. Arikan, C. F. Kumru, A. Erduman, N. Umurkan
The aim of this work is the experimental study of the electric field distribution around a line model in high voltage laboratory. Thereby study and knowledge of the electric field around a line at different voltage levels can be purposive for safety, settlements and design procedures of power lines. The measurements were carried out by using HOLADAY/HI-3604 electromagnetic field survey meter. Additionally, to compare the results obtained from the measurements, Finite Element Method Magnetics (FEMM) packaged program is used. The results show that the electric field intensity around a distribution line is changing with the distance in any direction. The electric field under and also near the distribution line is influenced with the increasing voltage levels.
{"title":"Electric field measurement and analysis around a line model at different voltage levels","authors":"C. Kocatepe, O. Arikan, C. F. Kumru, A. Erduman, N. Umurkan","doi":"10.1109/ICHVE.2012.6357005","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357005","url":null,"abstract":"The aim of this work is the experimental study of the electric field distribution around a line model in high voltage laboratory. Thereby study and knowledge of the electric field around a line at different voltage levels can be purposive for safety, settlements and design procedures of power lines. The measurements were carried out by using HOLADAY/HI-3604 electromagnetic field survey meter. Additionally, to compare the results obtained from the measurements, Finite Element Method Magnetics (FEMM) packaged program is used. The results show that the electric field intensity around a distribution line is changing with the distance in any direction. The electric field under and also near the distribution line is influenced with the increasing voltage levels.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"5 1","pages":"39-42"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77734348","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357089
R. Włodek
Ageing process of an insulation system appears in the final part of failure rate function v. exploitation time and it influences then the reliability of the device in this time interval of exploitation. Paper presents the different types of the time-to-failure distribution functions and their effects on the failure rate functions.
{"title":"Application of time-to-failure distributions for the modelling of ageing processes","authors":"R. Włodek","doi":"10.1109/ICHVE.2012.6357089","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357089","url":null,"abstract":"Ageing process of an insulation system appears in the final part of failure rate function v. exploitation time and it influences then the reliability of the device in this time interval of exploitation. Paper presents the different types of the time-to-failure distribution functions and their effects on the failure rate functions.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"25 8 1","pages":"532-535"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82564293","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357018
Nan-nan Yan, Z. Fu
In order to obtain the waveform of lightning current, the Rogowski coil is installed directly on tall structures such as the UHV transmission line towers. However, the measured results are influenced by the structure involved. This paper investigates the effects of different current-carrying bus positions to the large size Rogowski coil on the measured results. Two different large size coils' frequency spectrum characteristics are analyzed and the effects of coil parameters on frequency band are also discussed. The impact of current-carrying bus decentration and inclination the Rogowski coil measured results is investigated. Both calculation and test strategy study methods are employed for the impact investigation. It is shown that the decentration of current-carrying bus has little impact of less than 4% errors on the measurement results when the current-carrying bus's decentration distance changed from 0 cm to 30 cm. The inclination of the current carrying-bus has more significant impact on the measured results. The error of measured current amplitude changes from 1.17% to 7.4% whilst the inclination angle changes from 0°to 60°under 5kA impulse current, and from 1.5% to 17.9% under 10kA impulse current. The theoretical analysis is in accordance with the experimental results. It is suggested that the Rogowski coil should be located installed perpendicular to the current-carrying bus and the decentration impact is ignorable when the decentration distance is less then 20% of the coil radius.
{"title":"The impact of current-carrying bus decentration and inclination on impulse current measurement by large size Rogowski coils","authors":"Nan-nan Yan, Z. Fu","doi":"10.1109/ICHVE.2012.6357018","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357018","url":null,"abstract":"In order to obtain the waveform of lightning current, the Rogowski coil is installed directly on tall structures such as the UHV transmission line towers. However, the measured results are influenced by the structure involved. This paper investigates the effects of different current-carrying bus positions to the large size Rogowski coil on the measured results. Two different large size coils' frequency spectrum characteristics are analyzed and the effects of coil parameters on frequency band are also discussed. The impact of current-carrying bus decentration and inclination the Rogowski coil measured results is investigated. Both calculation and test strategy study methods are employed for the impact investigation. It is shown that the decentration of current-carrying bus has little impact of less than 4% errors on the measurement results when the current-carrying bus's decentration distance changed from 0 cm to 30 cm. The inclination of the current carrying-bus has more significant impact on the measured results. The error of measured current amplitude changes from 1.17% to 7.4% whilst the inclination angle changes from 0°to 60°under 5kA impulse current, and from 1.5% to 17.9% under 10kA impulse current. The theoretical analysis is in accordance with the experimental results. It is suggested that the Rogowski coil should be located installed perpendicular to the current-carrying bus and the decentration impact is ignorable when the decentration distance is less then 20% of the coil radius.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"45 4 1","pages":"166-169"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81039407","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357068
V. P. Androvitsaneas, F. Asimakopoulou, I. Gonos, I. Stathopulos
Grounding system constitutes an essential part of the protection system of electrical installations and power systems against lightning and fault currents. Therefore, it is of paramount importance that engineers ensure as low values for grounding resistance as possible, during the designing phase as well as the lifecycle of the grounding system. A widely used technique of reducing the grounding resistance value, in case of high soil resistivity values, or lack of adequate space for the installation of grounding systems, is the use of ground enhancing compounds. This paper presents a methodology, for the evaluation of grounding resistance, under various meteorological conditions, of grounding systems embedded in natural soil as well as in ground enhancing compounds, using Artificial Neural Network (ANN). The ANN training is based on field measurements that have been performed in Greece during the last year. As a matter of fact, this is a first step to develop a new method for estimating variations of grounding resistance value.
{"title":"Estimation of ground enhancing compound performance using Artificial Neural Network","authors":"V. P. Androvitsaneas, F. Asimakopoulou, I. Gonos, I. Stathopulos","doi":"10.1109/ICHVE.2012.6357068","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357068","url":null,"abstract":"Grounding system constitutes an essential part of the protection system of electrical installations and power systems against lightning and fault currents. Therefore, it is of paramount importance that engineers ensure as low values for grounding resistance as possible, during the designing phase as well as the lifecycle of the grounding system. A widely used technique of reducing the grounding resistance value, in case of high soil resistivity values, or lack of adequate space for the installation of grounding systems, is the use of ground enhancing compounds. This paper presents a methodology, for the evaluation of grounding resistance, under various meteorological conditions, of grounding systems embedded in natural soil as well as in ground enhancing compounds, using Artificial Neural Network (ANN). The ANN training is based on field measurements that have been performed in Greece during the last year. As a matter of fact, this is a first step to develop a new method for estimating variations of grounding resistance value.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"39 1","pages":"145-149"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90451120","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357004
H. L. Rasara, K. Wong
Power distribution and transmission networks widely adopt composite insulators for the overhead power line applications. The premature failure of these insulators due to the high electric field induced in them has become a major disappointment in the recent years. In this paper, an 11kV composite insulator is modelled in a three phase high voltage environment, and the induced electrical field is studied using finite element analysis. To reduce the computational time and resources, a simplified geometry for the insulator is also proposed. The electric field calculations are used to understand the importance of using a three phase supply in computational and experimental analysis of insulators, which we determine is more accurate than using a single phase supply.
{"title":"Electrical field and potential distribution of polymer insulators under the influence of a three phase supply","authors":"H. L. Rasara, K. Wong","doi":"10.1109/ICHVE.2012.6357004","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357004","url":null,"abstract":"Power distribution and transmission networks widely adopt composite insulators for the overhead power line applications. The premature failure of these insulators due to the high electric field induced in them has become a major disappointment in the recent years. In this paper, an 11kV composite insulator is modelled in a three phase high voltage environment, and the induced electrical field is studied using finite element analysis. To reduce the computational time and resources, a simplified geometry for the insulator is also proposed. The electric field calculations are used to understand the importance of using a three phase supply in computational and experimental analysis of insulators, which we determine is more accurate than using a single phase supply.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"1 1","pages":"35-38"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89787532","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357026
Shen Wei, Li Dejun, U. Schichler, B. Suermann
Gas-insulated switchgear (GIS) are used up to a nominal voltage of 1100 kV. One of the main GIS components are the solid epoxy insulators which are subject of ageing under mechanical and electrical stresses. Optimized insulator design based on calculations/simulations and intensive mechanical and electrical testing of insulators during research and development and manufacturing are key issues for a trouble-free life of GIS. Results from high-voltage long-duration tests on real-sized insulators are described in comparison with the return of experience from a GIS which was in service for more than 37 years.
{"title":"Performance of GIS epoxy insulators and related tests","authors":"Shen Wei, Li Dejun, U. Schichler, B. Suermann","doi":"10.1109/ICHVE.2012.6357026","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357026","url":null,"abstract":"Gas-insulated switchgear (GIS) are used up to a nominal voltage of 1100 kV. One of the main GIS components are the solid epoxy insulators which are subject of ageing under mechanical and electrical stresses. Optimized insulator design based on calculations/simulations and intensive mechanical and electrical testing of insulators during research and development and manufacturing are key issues for a trouble-free life of GIS. Results from high-voltage long-duration tests on real-sized insulators are described in comparison with the return of experience from a GIS which was in service for more than 37 years.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"129 1","pages":"225-228"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89307119","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 : 2012-11-26DOI: 10.1109/ICHVE.2012.6357015
R. Ziemba, G. Masłowski, G. Karnas, S. Wyderka
The paper presents computer results of current distribution for two different lightning current waveforms injected in the central part of a typical substation grounding grid buried in an uniform soil and two different two-layered soils with positive and negative reflection factors, respectively. Obtained results show that the modules of the input impedance of the grounding systems differ significantly and are almost constant in the low-frequency range being practically the same as dc grounding resistances. The computed input impedances increase rapidly above 10 kHz and reach at 1 MHz similar values for both two-layered soils. The lightning current flowing in the horizontal conductors of the analysed grounding grid with vertical rods is slightly greater in the outer edges than current for the same grounding system and soil but without the vertical rods for both injected current waveforms with relatively slow and very fast rising wavefronts.
{"title":"Distribution of lightning current in the grounding grid for different multilayer soil models","authors":"R. Ziemba, G. Masłowski, G. Karnas, S. Wyderka","doi":"10.1109/ICHVE.2012.6357015","DOIUrl":"https://doi.org/10.1109/ICHVE.2012.6357015","url":null,"abstract":"The paper presents computer results of current distribution for two different lightning current waveforms injected in the central part of a typical substation grounding grid buried in an uniform soil and two different two-layered soils with positive and negative reflection factors, respectively. Obtained results show that the modules of the input impedance of the grounding systems differ significantly and are almost constant in the low-frequency range being practically the same as dc grounding resistances. The computed input impedances increase rapidly above 10 kHz and reach at 1 MHz similar values for both two-layered soils. The lightning current flowing in the horizontal conductors of the analysed grounding grid with vertical rods is slightly greater in the outer edges than current for the same grounding system and soil but without the vertical rods for both injected current waveforms with relatively slow and very fast rising wavefronts.","PeriodicalId":6375,"journal":{"name":"2012 International Conference on High Voltage Engineering and Application","volume":"28 1","pages":"137-140"},"PeriodicalIF":0.0,"publicationDate":"2012-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85775674","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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