Pub Date : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509131
Yubo Zhang, Zhiming Huang, R. Zhuo, M. Fu, Zhangting Yu, Lei Zhang, Yan Luo, Yue Yu
This paper presents an investigation on the characteristics of damping and X-wax defects of oil-paper insulated bushing, with a combination of oil chromatograph and Frequency Domain Spectroscopy (FDS) and disintegration analysis. Firstly, based on the disintegration analysis and oil chromatography analysis of five 500 kV bushings with different service periods, the difference of dissolved gas component content in the bushing oil were obtained and were related to damping and X-wax defects. The results show that in the bushing suffering X-wax defect the oil contains a large amount of hydrogen (over $10000 mumathrm{L}/mathrm{L}$) and methane, and that shall be acted as a significant characteristic of the X-wax defect. Nevertheless, the content of carbon dioxide (CO2), acetylene (C2H2), ethylene (C2H4) and moisture in the oil of the bushing suffering damping defect is clearly higher than that in the defective bushings with X-wax. Secondly, the frequency domain dielectric spectrum (FDS) analysis of 5 bushings in service and 1 new bushing was conducted. It shows that the FDS is sensitive to moisture and x-wax defects of the bushings. In addition, the moisture mainly affects the dielectric loss of low frequency band (1mHz∼10mHz) of FDS curves. The X-wax defect has little effect on the low frequency band (1mHz∼10mHz) of FDS curves, but mainly affects the dielectric loss of 0.1Hz∼10Hz frequency band of FDS curves.
{"title":"An Analysis of the Characteristics of Oil-Paper Insulated Bushing with Moisture and X-wax Defects Through Oil Chromatographic and Frequency Domain Spectroscopy","authors":"Yubo Zhang, Zhiming Huang, R. Zhuo, M. Fu, Zhangting Yu, Lei Zhang, Yan Luo, Yue Yu","doi":"10.1109/ICEMPE51623.2021.9509131","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509131","url":null,"abstract":"This paper presents an investigation on the characteristics of damping and X-wax defects of oil-paper insulated bushing, with a combination of oil chromatograph and Frequency Domain Spectroscopy (FDS) and disintegration analysis. Firstly, based on the disintegration analysis and oil chromatography analysis of five 500 kV bushings with different service periods, the difference of dissolved gas component content in the bushing oil were obtained and were related to damping and X-wax defects. The results show that in the bushing suffering X-wax defect the oil contains a large amount of hydrogen (over $10000 mumathrm{L}/mathrm{L}$) and methane, and that shall be acted as a significant characteristic of the X-wax defect. Nevertheless, the content of carbon dioxide (CO2), acetylene (C2H2), ethylene (C2H4) and moisture in the oil of the bushing suffering damping defect is clearly higher than that in the defective bushings with X-wax. Secondly, the frequency domain dielectric spectrum (FDS) analysis of 5 bushings in service and 1 new bushing was conducted. It shows that the FDS is sensitive to moisture and x-wax defects of the bushings. In addition, the moisture mainly affects the dielectric loss of low frequency band (1mHz∼10mHz) of FDS curves. The X-wax defect has little effect on the low frequency band (1mHz∼10mHz) of FDS curves, but mainly affects the dielectric loss of 0.1Hz∼10Hz frequency band of FDS curves.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"73 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80398827","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 : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509243
G. Ferraz, Laerty J. S. Damião, R. Capelini, R. Salustiano
The assessment of the insulation condition of a transformer is of great importance for the operational efficiency of the power system. However, as insulation systems are complex, many challenges are seen in terms of methods of analysis and measurement of critical parameters. In this context, this paper presents the application of an online monitoring system specially developed for the detection of partial discharges (PDs), which are recognized as a phenomenon that carries relevant information regarding the health of a transformer. The results were explored to show how the PD pattern and its correlation with gases dissolved in oil can be analyzed in practical situations with the equipment in service.
{"title":"Assessment of the Insulation Conditions of Power Transformers Through Online Monitoring of Partial Discharges","authors":"G. Ferraz, Laerty J. S. Damião, R. Capelini, R. Salustiano","doi":"10.1109/ICEMPE51623.2021.9509243","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509243","url":null,"abstract":"The assessment of the insulation condition of a transformer is of great importance for the operational efficiency of the power system. However, as insulation systems are complex, many challenges are seen in terms of methods of analysis and measurement of critical parameters. In this context, this paper presents the application of an online monitoring system specially developed for the detection of partial discharges (PDs), which are recognized as a phenomenon that carries relevant information regarding the health of a transformer. The results were explored to show how the PD pattern and its correlation with gases dissolved in oil can be analyzed in practical situations with the equipment in service.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"29 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81635245","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 : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509188
Yi Ding, Yalin Wang, Mingyu Zhou, Haoran Sun, Wenyi Li, Y. Yin
Exploring the partial discharge (PD) characteristics of power modules under square wave high electric fields with short rise and fall time is of great significance for improving the reliability of its packaging insulation. In this paper, a PD detection method based on super high frequency (SHF, 3-30 GHz) technique and signal down-mixing principle is applied to detect the PD under square wave. The power module packaging insulation specimen consisting of metal baseplate, direct bonding copper (DBC), substrate and housing is fabricated. A repetitive square wave generator is built to supply high voltage square waves with short transition time. PD experiments are performed under square wave and sinusoidal wave. Experimental results show that the SHF-down-mixing PD detection system can effectively suppress the electromagnetic interference (EMI) from the square wave and extract PD signals successfully. As the radius of the electrode corner increases, the partial discharge inception voltage (PDIV) values under the sinusoidal wave also gradually increases. The PDIV under square wave does not show a monotonically increasing and is usually higher than that under sinusoidal wave probably because of the effect of space charge accumulation.
{"title":"Partial Discharge Measurement of Power Module Packaging Insulation Under Square Wave with Short Transition Time Based on SHF-Down-Mixing Method","authors":"Yi Ding, Yalin Wang, Mingyu Zhou, Haoran Sun, Wenyi Li, Y. Yin","doi":"10.1109/ICEMPE51623.2021.9509188","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509188","url":null,"abstract":"Exploring the partial discharge (PD) characteristics of power modules under square wave high electric fields with short rise and fall time is of great significance for improving the reliability of its packaging insulation. In this paper, a PD detection method based on super high frequency (SHF, 3-30 GHz) technique and signal down-mixing principle is applied to detect the PD under square wave. The power module packaging insulation specimen consisting of metal baseplate, direct bonding copper (DBC), substrate and housing is fabricated. A repetitive square wave generator is built to supply high voltage square waves with short transition time. PD experiments are performed under square wave and sinusoidal wave. Experimental results show that the SHF-down-mixing PD detection system can effectively suppress the electromagnetic interference (EMI) from the square wave and extract PD signals successfully. As the radius of the electrode corner increases, the partial discharge inception voltage (PDIV) values under the sinusoidal wave also gradually increases. The PDIV under square wave does not show a monotonically increasing and is usually higher than that under sinusoidal wave probably because of the effect of space charge accumulation.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"4 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85600434","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 : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509089
Xiaokang Wang, Bo Niu, B. Hu, Haichuan Jin, Zhiyong Wu, Dongfang Wang
To achieve the high precision location of partial discharge defects found during the live detection, the electroacoustic location modelling is performed on the air-insulation switchgear in this paper based on the time difference of arrival algorithm by exploiting the homology of photoelectric signals generated in the PD process. Furthermore, the PD location accuracy of electrical equipment on the TDOA delay is reduced through the particle swarm optimization of location results. With the combination of ultrasonic associated with electromagnetic wave type and particle swarm optimization of localization results, the influence of background interference on localization accuracy can be further reduced, which has higher detection flexibility and localization accuracy. The technique can be applied to localization of partial discharge defects in air-insulation during live detection.
{"title":"Research on Partial Discharge Source Positioning in Switchgear Based on PSO","authors":"Xiaokang Wang, Bo Niu, B. Hu, Haichuan Jin, Zhiyong Wu, Dongfang Wang","doi":"10.1109/ICEMPE51623.2021.9509089","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509089","url":null,"abstract":"To achieve the high precision location of partial discharge defects found during the live detection, the electroacoustic location modelling is performed on the air-insulation switchgear in this paper based on the time difference of arrival algorithm by exploiting the homology of photoelectric signals generated in the PD process. Furthermore, the PD location accuracy of electrical equipment on the TDOA delay is reduced through the particle swarm optimization of location results. With the combination of ultrasonic associated with electromagnetic wave type and particle swarm optimization of localization results, the influence of background interference on localization accuracy can be further reduced, which has higher detection flexibility and localization accuracy. The technique can be applied to localization of partial discharge defects in air-insulation during live detection.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"16 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85888801","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}
In past earthquakes, a large number of surge arresters were damaged due to the low strength of materials. Compared with directly enlarging profiles of components, adopting isolation may be a more cost-effective way to improve the seismic performance of post electrical equipment. In this study, a numerical analysis of a representative 220 kV surge arrester is conducted. Since the stress safety factor of surge arrester under severe seismic inputs cannot satisfy the requirement of 1.67, the wire rope isolation is introduced. Based on the modified Bouc-wen model, the wire ropes are modeled as user-define elements. Then the arrangement and selection of wire ropes are determined based on the displacement and stress response of the isolated surge arrester. The results show that the wire rope isolation with proper configuration can effectively improve the seismic performance of surge arrester by reducing the stress while slightly increasing displacement response. Therefore, wire rope isolation is recommended for high voltage post equipment in seismic areas.
{"title":"Seismic performance and isolation design for 220kV surge arrester","authors":"Hao Li, Long Shen, Yaolong Wang, Xin Wang, Zhenyu Yang, Q. Xie","doi":"10.1109/ICEMPE51623.2021.9509124","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509124","url":null,"abstract":"In past earthquakes, a large number of surge arresters were damaged due to the low strength of materials. Compared with directly enlarging profiles of components, adopting isolation may be a more cost-effective way to improve the seismic performance of post electrical equipment. In this study, a numerical analysis of a representative 220 kV surge arrester is conducted. Since the stress safety factor of surge arrester under severe seismic inputs cannot satisfy the requirement of 1.67, the wire rope isolation is introduced. Based on the modified Bouc-wen model, the wire ropes are modeled as user-define elements. Then the arrangement and selection of wire ropes are determined based on the displacement and stress response of the isolated surge arrester. The results show that the wire rope isolation with proper configuration can effectively improve the seismic performance of surge arrester by reducing the stress while slightly increasing displacement response. Therefore, wire rope isolation is recommended for high voltage post equipment in seismic areas.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"698 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76889589","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}
Stress concentration may be an important cause for mechanical strength deterioration of GIS/GIL insulators. Ultrasonic detection technology of stress has the advantages of good directivity, nondestructive and high efficiency. In this paper, three kinds of LabVIEW visual detection platforms are designed. One is the platform of ultrasonic longitudinal wave penetration, which is used to detect the stress of epoxy in three-post insulators. One is the platform of ultrasonic longitudinal wave reflection, which is used to detect the stress of epoxy outside grounding insert of three-post insulators. The last one is the platform of ultrasonic critical refraction longitudinal wave, which is used to detect the surface stress of basin insulators. Taking a 550 kV GIL three-post insulator and a 252 kV GIS basin insulator as the research objects, the ultrasonic detection for stress of insulators is carried out. It is found that the stress of epoxy in a post of the three-post insulator is −0.008 MPa. The stress of epoxy outside grounding insert of the three-post insulator is −0.007 MPa. The surface stress of the basin insulator is 0.423 MPa when no external load is applied. The platforms can be used to detect the stress of insulators conveniently and quickly, which provides the foundation for subsequent engineering applications of the stress detection on GIS/GIL insulators.
{"title":"Visual Platforms for Ultrasonic Detection of the Stress in GIS/GIL Insulators","authors":"Weiguo Li, Jinwei Chu, Wanying Liu, F. Zhou, Chao Gao, Ruodong Huang, Yi-Ning Zhang","doi":"10.1109/ICEMPE51623.2021.9509155","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509155","url":null,"abstract":"Stress concentration may be an important cause for mechanical strength deterioration of GIS/GIL insulators. Ultrasonic detection technology of stress has the advantages of good directivity, nondestructive and high efficiency. In this paper, three kinds of LabVIEW visual detection platforms are designed. One is the platform of ultrasonic longitudinal wave penetration, which is used to detect the stress of epoxy in three-post insulators. One is the platform of ultrasonic longitudinal wave reflection, which is used to detect the stress of epoxy outside grounding insert of three-post insulators. The last one is the platform of ultrasonic critical refraction longitudinal wave, which is used to detect the surface stress of basin insulators. Taking a 550 kV GIL three-post insulator and a 252 kV GIS basin insulator as the research objects, the ultrasonic detection for stress of insulators is carried out. It is found that the stress of epoxy in a post of the three-post insulator is −0.008 MPa. The stress of epoxy outside grounding insert of the three-post insulator is −0.007 MPa. The surface stress of the basin insulator is 0.423 MPa when no external load is applied. The platforms can be used to detect the stress of insulators conveniently and quickly, which provides the foundation for subsequent engineering applications of the stress detection on GIS/GIL insulators.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"32 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76923553","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 : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509181
Zhangting Yu, Dajian Li, Liangyuan Chen
In order to measure the aging state of silicone rubber insulators, a new method of nuclear magnetic resonance(NMR) measurement is proposed and a portable low field NMR measurement system is developed. This paper introduced a design method of magnet and RF coil of NMR sensor and made a experiment about the aging of composite insulators on 220kV high voltage. The study draw a conclusion that the transverse relaxation time of composite insulators decreases with the increasing of running time. Therefore, low-field NMR can be used to evaluate the aging state of composite insulator umbrella skirt quantitatively.
{"title":"A new method of nuclear magnetic resonance for aging State detection of composite insulators","authors":"Zhangting Yu, Dajian Li, Liangyuan Chen","doi":"10.1109/ICEMPE51623.2021.9509181","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509181","url":null,"abstract":"In order to measure the aging state of silicone rubber insulators, a new method of nuclear magnetic resonance(NMR) measurement is proposed and a portable low field NMR measurement system is developed. This paper introduced a design method of magnet and RF coil of NMR sensor and made a experiment about the aging of composite insulators on 220kV high voltage. The study draw a conclusion that the transverse relaxation time of composite insulators decreases with the increasing of running time. Therefore, low-field NMR can be used to evaluate the aging state of composite insulator umbrella skirt quantitatively.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"87 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81003553","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 : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509235
Yimeng Li, B. Du, Jin Li, Zhonglei Li, T. Han, Z. Ran
In this paper, graphene/silicone rubber (SiR) nanocomposites with filler contents of 0.001 ∼ 0.005 wt % are prepared to improve electrical tree inhibiting ability under different temperature gradients. The electrical treeing test is performed under three temperature gradients, by controlling the temperature of high voltage and ground sides. Experimental results indicate that the SiR sample with 0.003 wt% graphene presents the best performance on electrical tree resistance. The tree length and accumulated damage are both reduced with the increase of graphene content from 0 to 0.003 wt %, but increased with the further increase of filler content from 0.003 to 0.005 wt %. The tree outline tends to be circular in neat SiR under negative temperature gradient, while is triangular under positive temperature gradient. However, the effect of temperature gradient is weakened when graphene exists. The doping of graphene leads to deeper trap sites at the interfaces between nanoplatelets and polymer matrix, which enhances electrical resistances of SiR. This research provides an effective method to suppress electrical trees of SiR for cable accessories.
{"title":"Electrical Tree Characteristics in Graphene/SiR Nanocomposites under Temperature Gradient","authors":"Yimeng Li, B. Du, Jin Li, Zhonglei Li, T. Han, Z. Ran","doi":"10.1109/ICEMPE51623.2021.9509235","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509235","url":null,"abstract":"In this paper, graphene/silicone rubber (SiR) nanocomposites with filler contents of 0.001 ∼ 0.005 wt % are prepared to improve electrical tree inhibiting ability under different temperature gradients. The electrical treeing test is performed under three temperature gradients, by controlling the temperature of high voltage and ground sides. Experimental results indicate that the SiR sample with 0.003 wt% graphene presents the best performance on electrical tree resistance. The tree length and accumulated damage are both reduced with the increase of graphene content from 0 to 0.003 wt %, but increased with the further increase of filler content from 0.003 to 0.005 wt %. The tree outline tends to be circular in neat SiR under negative temperature gradient, while is triangular under positive temperature gradient. However, the effect of temperature gradient is weakened when graphene exists. The doping of graphene leads to deeper trap sites at the interfaces between nanoplatelets and polymer matrix, which enhances electrical resistances of SiR. This research provides an effective method to suppress electrical trees of SiR for cable accessories.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"126 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85703531","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 : 2021-04-11DOI: 10.1109/ICEMPE51623.2021.9509213
Zihan He, H. Wu, X. Hu
Bird damage is one of the main reasons for transmission line tripping or even outage. In order to analyze the characteristics and causes of bird damage faults, the bird damage faults of 110 kV and above transmission lines in Ningxia Power Grid from 2015 to 2020 are statistically analyzed. The results show that most of the bird faults in Ningxia power grid occur in plain and farmland, and most of them occur from July to October. The main cause of the fault is bird manure flashover, and all of them are short air gap flashover. In view of this phenomenon, the electric field distribution of composite insulator with grading ring is studied. The results show that the installation of grading ring greatly reduces the electric field along the insulator surface. At the same time, the pipe diameter and diameter of grading ring are selected as $R=mathrm{30}$ mm and $D=mathrm{260}$ mm, respectively. The application of insulation grading ring reduces the electric field along the surface of composite insulator, and different insulation layers and their thicknesses should be determined according to different voltage levels.
{"title":"Analysis on Bird Damage Accident of Overhead Transmission Lines in Ningxia Region and Optimization Design of Insulating Grading Ring","authors":"Zihan He, H. Wu, X. Hu","doi":"10.1109/ICEMPE51623.2021.9509213","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509213","url":null,"abstract":"Bird damage is one of the main reasons for transmission line tripping or even outage. In order to analyze the characteristics and causes of bird damage faults, the bird damage faults of 110 kV and above transmission lines in Ningxia Power Grid from 2015 to 2020 are statistically analyzed. The results show that most of the bird faults in Ningxia power grid occur in plain and farmland, and most of them occur from July to October. The main cause of the fault is bird manure flashover, and all of them are short air gap flashover. In view of this phenomenon, the electric field distribution of composite insulator with grading ring is studied. The results show that the installation of grading ring greatly reduces the electric field along the insulator surface. At the same time, the pipe diameter and diameter of grading ring are selected as $R=mathrm{30}$ mm and $D=mathrm{260}$ mm, respectively. The application of insulation grading ring reduces the electric field along the surface of composite insulator, and different insulation layers and their thicknesses should be determined according to different voltage levels.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"59 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81455370","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}
The residual stress could be produced during the curing process of GIS basin insulators. The coupling of residual stress and external stress may cause stress concentration, which threaten the safe operation of the insulators. In this paper, the method for detecting residual stress of a 252kV GIS basin insulator by critical refraction longitudinal wave (LCR) is presented. The residual stress detection system is built. The main frequency of excitation and receiving probe is 2 MHz. The ultrasonic velocity of epoxy resin standard sample is measured. Two checkpoints on the basin insulator are selected for the circumferential residual stress detection with a distance of 5 mm. The results show that ultrasonic velocity of the standard sample is 2927 m/s. The ultrasonic propagation time of the two checkpoints is different. Near the central conductor, the ultrasonic velocity is 3399 m/s and the compressive residual stress is 0.38 MPa. The ultrasonic velocity is 3073 m/s and the compressive residual stress is 0.12 MPa far away from the central conductor.
{"title":"Measurement of Residual Stress in GIS Basin Insulators by Using Ultrasonic Longitudinal Critically Refracted Wave Method","authors":"Xu Yang, Changhong Zhang, Weiguo Li, Chao Gao, F. Zhou, Ruodong Huang, Guoli Wang, Xuezhi Liang","doi":"10.1109/ICEMPE51623.2021.9509141","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509141","url":null,"abstract":"The residual stress could be produced during the curing process of GIS basin insulators. The coupling of residual stress and external stress may cause stress concentration, which threaten the safe operation of the insulators. In this paper, the method for detecting residual stress of a 252kV GIS basin insulator by critical refraction longitudinal wave (LCR) is presented. The residual stress detection system is built. The main frequency of excitation and receiving probe is 2 MHz. The ultrasonic velocity of epoxy resin standard sample is measured. Two checkpoints on the basin insulator are selected for the circumferential residual stress detection with a distance of 5 mm. The results show that ultrasonic velocity of the standard sample is 2927 m/s. The ultrasonic propagation time of the two checkpoints is different. Near the central conductor, the ultrasonic velocity is 3399 m/s and the compressive residual stress is 0.38 MPa. The ultrasonic velocity is 3073 m/s and the compressive residual stress is 0.12 MPa far away from the central conductor.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"35 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78669876","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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