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Hollow porcelain insulators in substations are frequently confronted with rain flashovers under extreme rainfall. This study aims to investigate the spatial and temporal variation of electric fields between hollow porcelain insulator sheds affected by dynamic deformation of pendant water drops and effects of the dimensionless number of fluids, the Weber number (We) and the electric Bond number (BoE), on it for influencing factors' analysis. Flow-electric field coupling simulations were carried out to compute the magnitude and the position of AC electric fields between the sheds. The results show that the maximum electric field at a point in time (Etmax) increases significantly after the breakup of the pendant water drop, and its position alters accordingly. For low We and BoE, the global maximum electric field (Egmax) increases with increasing We and BoE, respectively. It is much closer to the adjacent sheds and occurs later than Etmax at the breakup of the pendant water drop (Ebmax). By contrast, Egmax decreases in different degrees at high We and BoE, respectively. There is little difference between Egmax and Ebmax in the position and the occurring time. The influence mechanism on the maximum electric field and discharges and the relationship between discharges induced by the pendant water drop and rain flashover are discussed.
Yijie Sun; Lin Yang; Gaofeng Shang; Zhiqiang Kuang; Yifan Liao; Yanpeng Hao; Licheng Li. Effects of dynamic deformation of pendant water drops on the electric field between hollow porcelain insulator sheds under extreme rainfall. High Voltage 2021, 1 .
AMA StyleYijie Sun, Lin Yang, Gaofeng Shang, Zhiqiang Kuang, Yifan Liao, Yanpeng Hao, Licheng Li. Effects of dynamic deformation of pendant water drops on the electric field between hollow porcelain insulator sheds under extreme rainfall. High Voltage. 2021; ():1.
Chicago/Turabian StyleYijie Sun; Lin Yang; Gaofeng Shang; Zhiqiang Kuang; Yifan Liao; Yanpeng Hao; Licheng Li. 2021. "Effects of dynamic deformation of pendant water drops on the electric field between hollow porcelain insulator sheds under extreme rainfall." High Voltage , no. : 1.
Rain is one of the dominant meteorological factors threatening the outdoor insulation performance of ultra-high voltage (UHV) power stations. Discharge occurring on the polluted surface of post insulators in rain has always been a major concern of power stations. Previous studies have shown that suspended water droplets on the shed edge play an important role in the rain flashover process. In this work, artificial contamination rain flashover tests were carried out in a laboratory on a UHV DC (Ultra-High Voltage Direct Current) large-diameter composite post insulator, which had a rod diameter of 625 mm and alternating sheds (105 mm and 75 mm for larger and smaller shed overhang, respectively). The discharge mechanism was analyzed base on the observation of discharge phenomenon of suspended water-drops on the shed edge. Moreover, simulation models by COMSOL Multiphysics were established to investigate the electric field around sheds and suspended water-drops, as well as the shape change of water droplets on the insulation surface, especially at the edge of the shed. Results show that the shape parameters of water-droplets changed continuously under the combined action of gravity, surface tension, and capillary tension. Suspended water-droplets on the shed edge showed a great influence on the electric field distribution, and the resulting discharge lead to the bridging between sheds. This work paves a new way to revealing the contamination rain flashover mechanism on post insulators and provides critical knowledge for power stations on preventing flashover accidents.
Yifan Liao; Qiao Wang; Lin Yang; Zhiqiang Kuang; Yanpeng Hao; Chuyan Zhang. Discharge Behavior and Morphological Characteristics of Suspended Water-Drop on Shed Edge during Rain Flashover of Polluted Large-Diameter Post Insulator. Energies 2021, 14, 1652 .
AMA StyleYifan Liao, Qiao Wang, Lin Yang, Zhiqiang Kuang, Yanpeng Hao, Chuyan Zhang. Discharge Behavior and Morphological Characteristics of Suspended Water-Drop on Shed Edge during Rain Flashover of Polluted Large-Diameter Post Insulator. Energies. 2021; 14 (6):1652.
Chicago/Turabian StyleYifan Liao; Qiao Wang; Lin Yang; Zhiqiang Kuang; Yanpeng Hao; Chuyan Zhang. 2021. "Discharge Behavior and Morphological Characteristics of Suspended Water-Drop on Shed Edge during Rain Flashover of Polluted Large-Diameter Post Insulator." Energies 14, no. 6: 1652.
The multifactor accelerated aging test is an important means to predict the lifetime of gas-insulated switchgear (GIS) O-ring seals, while the leakage rate (LR) is a potential index for failure evaluation. This article proposed a three-factor accelerated aging test platform and a leakage test system (LTS) for GIS seal rings. The aging factors are thermal, mechanical compression, and pressured SF 6 gas. The pressure aging vessel (PAV) can be filled with various gases to simulate the operating conditions of the GIS and age multiple samples simultaneously. During the aging process, leakage tests are conducted on flange pairs without disassembling and separating the seal rings. After the test, the aging can be continued so as to study the evolution of LR with aging time. In order to analyze the properties of leakage test and validate the platform, a three-factor accelerated aging and a traditional two-factor accelerated aging (thermal and compression) were conducted on GIS O-ring seals of EPDM material. Compression set (CS) and LR were tested. The result showed that a steady inherent LR $F_{0}$ exists for the LTS. The LR rose linearly with accumulating time, allowing simplified calculation of LR. The three-factor aged samples had significantly smaller CS than those of the two-factor aged samples, indicating that the working condition of GIS with SF 6 atmosphere significantly slows the aging rate of GIS seal rings. The findings proved that the three-factor accelerated aging test platform and LTS effectively simulate the operating conditions of GIS seal rings and evaluate their properties.
Zhimin Zhang; Yanpeng Hao; Jiahao Peng; Lin Yang; Chao Gao; Guoli Wang; Fusheng Zhou; Yun Yang; Hangyu Cao; Licheng Li. A Three-Factor Accelerated Aging Test Platform of Thermal, Mechanical Compression, Pressured SF6, and a Leakage Test System for GIS O-Ring Seals. IEEE Transactions on Instrumentation and Measurement 2021, 70, 1 -11.
AMA StyleZhimin Zhang, Yanpeng Hao, Jiahao Peng, Lin Yang, Chao Gao, Guoli Wang, Fusheng Zhou, Yun Yang, Hangyu Cao, Licheng Li. A Three-Factor Accelerated Aging Test Platform of Thermal, Mechanical Compression, Pressured SF6, and a Leakage Test System for GIS O-Ring Seals. IEEE Transactions on Instrumentation and Measurement. 2021; 70 ():1-11.
Chicago/Turabian StyleZhimin Zhang; Yanpeng Hao; Jiahao Peng; Lin Yang; Chao Gao; Guoli Wang; Fusheng Zhou; Yun Yang; Hangyu Cao; Licheng Li. 2021. "A Three-Factor Accelerated Aging Test Platform of Thermal, Mechanical Compression, Pressured SF6, and a Leakage Test System for GIS O-Ring Seals." IEEE Transactions on Instrumentation and Measurement 70, no. : 1-11.
The discharges of water columns and droplets between the sheds make the leakage distance not effectively used, which is one of the main reasons for flashover of composite post insulators under heavy rainfall. To study the influence of shed parameters on surface rainwater characteristics, artificial rain tests were carried out on the large-diameter composite post insulators under the rainfall intensity of 2–15 mm/min. Lwc (the length of water columns at the edge of large sheds), Nwc (the number of water columns at the edge of large sheds), Nwde (the number of water droplets at the edge of large sheds) and Nwds (the number of water droplets in the space between two adjacent large sheds) were proposed as the parameters of surface rainwater characteristics. The influences of large shed spacing, large shed overhang and rod diameter on the parameters of surface rainwater characteristics under different rainfall intensities were analyzed. The experimental results show that, under the same rainfall intensity, with the rise in large shed spacing, large shed overhang or rod diameter, Lwc, Nwc, Nwde and Nwds all increase. Under different rainfall intensities, the trends of the parameters with the change in shed parameters are basically invariant; however, the change ranges of the parameters are different. The increases in the parameters with the rises in shed parameters and rainfall intensity are mainly attributed to the change in the rainfall on the insulator surface. The experimental results can provide references for the quantitative description of surface rainwater characteristics and the design of large-diameter composite post insulators for DC transmission systems.
Yanpeng Hao; Yifan Liao; Zhiqiang Kuang; Yijie Sun; Gaofeng Shang; Weixun Zhang; Guiyun Mao; Lin Yang; Fuzeng Zhang; Licheng Li. Experimental Investigation on Influence of Shed Parameters on Surface Rainwater Characteristics of Large-Diameter Composite Post Insulators under Rain Conditions. Energies 2020, 13, 5011 .
AMA StyleYanpeng Hao, Yifan Liao, Zhiqiang Kuang, Yijie Sun, Gaofeng Shang, Weixun Zhang, Guiyun Mao, Lin Yang, Fuzeng Zhang, Licheng Li. Experimental Investigation on Influence of Shed Parameters on Surface Rainwater Characteristics of Large-Diameter Composite Post Insulators under Rain Conditions. Energies. 2020; 13 (19):5011.
Chicago/Turabian StyleYanpeng Hao; Yifan Liao; Zhiqiang Kuang; Yijie Sun; Gaofeng Shang; Weixun Zhang; Guiyun Mao; Lin Yang; Fuzeng Zhang; Licheng Li. 2020. "Experimental Investigation on Influence of Shed Parameters on Surface Rainwater Characteristics of Large-Diameter Composite Post Insulators under Rain Conditions." Energies 13, no. 19: 5011.
To perfect the wetting mechanism of hydrophobic insulators, it is urgent to explore the impact of hydrophobicity on wetting characteristics of the pollution layer of composite insulators. In this paper, the wetting test of the hydrophobic pollution layer was carried out in artificial hot fog. The local surface conductivity of the pollution layer with different hydrophobicity were measured. The test results show that the local surface conductivities of different hydrophobic pollution layers are obviously different at the same wetting time. For researching the regularity of wetting process in greater detail, three characteristic quantities were proposed to represent the wetting characteristics. They are the duration of local surface conductivity close to zero (DLSCCZ), the saturated wetting time (SWT) and the maximum value of local surface conductivity (MVLSC). With the enhancement of hydrophobicity of the pollution layer, DLSCCZ and SWT increase, while MVLSC and the growth velocity of local surface conductivity both decrease.
Jikai Bi; Yanpeng Hao; Lin Yang; Yao Zheng; Licheng Li. Impact of Hydrophobicity on Wetting Characteristics of Composite Insulators. IEEE Access 2020, 8, 159316 -159323.
AMA StyleJikai Bi, Yanpeng Hao, Lin Yang, Yao Zheng, Licheng Li. Impact of Hydrophobicity on Wetting Characteristics of Composite Insulators. IEEE Access. 2020; 8 (99):159316-159323.
Chicago/Turabian StyleJikai Bi; Yanpeng Hao; Lin Yang; Yao Zheng; Licheng Li. 2020. "Impact of Hydrophobicity on Wetting Characteristics of Composite Insulators." IEEE Access 8, no. 99: 159316-159323.
The flashover performance of insulators can be improved by BS (booster sheds) in the rain, which is mainly attributed to the reasons that BS break up long cascades of water and block connections of arcs. However, surface rainwater characteristics and arc characteristics of bushing have not been quantitatively studied under heavy rainfall. In this paper, the artificial rain tests were conducted on a 500 kV transformer high-voltage bushing equipped with and without BS under the rainfall intensity of 10 mm/min. X (the total length of water column) and Larc (the critical length of arc) on the bushing surface were taken as the feature parameters of surface rainwater characteristics and arc characteristics, respectively. The effects of BS on Eh (the rain flashover voltage gradient along the insulation height), X and Larc were investigated, respectively. Furtherly, the relationships were studied among Eh, X and Larc. Results indicate that Eh has a sharp rise as the number of BS (NBS) is from one to two, however the rise of Eh gradually decreases when NBS exceeds two. X decreases while Larc increases with the rise of NBS, however both the change ranges of them continually fall. Furthermore, Larc presents remarkable negative correlation to X because of the effect of the electric field. Eh rises nonlinearly with the decrease of X, which is due to the change of the wetting uniformity on the bushing surface and the potential redistribution along air gaps in the presence of the local arc.
Lin Yang; Zhiqiang Kuang; Yijie Sun; Yifan Liao; Yanpeng Hao; Licheng Li; Fuzeng Zhang. Study on Surface Rainwater and Arc Characteristics of High-Voltage Bushing With Booster Sheds Under Heavy Rainfall. IEEE Access 2020, 8, 146865 -146875.
AMA StyleLin Yang, Zhiqiang Kuang, Yijie Sun, Yifan Liao, Yanpeng Hao, Licheng Li, Fuzeng Zhang. Study on Surface Rainwater and Arc Characteristics of High-Voltage Bushing With Booster Sheds Under Heavy Rainfall. IEEE Access. 2020; 8 (99):146865-146875.
Chicago/Turabian StyleLin Yang; Zhiqiang Kuang; Yijie Sun; Yifan Liao; Yanpeng Hao; Licheng Li; Fuzeng Zhang. 2020. "Study on Surface Rainwater and Arc Characteristics of High-Voltage Bushing With Booster Sheds Under Heavy Rainfall." IEEE Access 8, no. 99: 146865-146875.
Internal stress in basin insulators of gas-insulated metal-enclosed switchgear (GIS) can lead to cracks, which affects the safe operation of these apparatuses. In this research, we proposed a subsurface internal stress measurement method for GIS epoxy composites. This method is based on an ultrasonic longitudinal critically refracted (LCR) wave technique. In this study, some epoxy composite specimens were synthesized with similar materials and manufacturing processes to those of 252 kV GIS basin insulators. An ultrasonic stress measurement system that utilized the LCR wave technique was set-up to investigate the relationship between stress and LCR wave propagation time, as well as to measure the compressive stress of the epoxy specimen within 0–50 MPa. The results show that LCR wave propagation time linearly decreased when stress increased in the subsurface zone and the acoustoelastic coefficient was −4.95. We found the relative errors of stress measurements to be less than 13%.
Zhouyiao Zou; Yanpeng Hao; Yao Zheng; Weiming He; Fangyuan Tian; Lin Yang; Licheng Li. Subsurface Stress Measurement in GIS Epoxy Composite by Using LCR Waves. Energies 2020, 13, 3725 .
AMA StyleZhouyiao Zou, Yanpeng Hao, Yao Zheng, Weiming He, Fangyuan Tian, Lin Yang, Licheng Li. Subsurface Stress Measurement in GIS Epoxy Composite by Using LCR Waves. Energies. 2020; 13 (14):3725.
Chicago/Turabian StyleZhouyiao Zou; Yanpeng Hao; Yao Zheng; Weiming He; Fangyuan Tian; Lin Yang; Licheng Li. 2020. "Subsurface Stress Measurement in GIS Epoxy Composite by Using LCR Waves." Energies 13, no. 14: 3725.
Flashover accidents on high-voltage bushings frequently occur under extreme rainfall, which is generally attributed to the bridging of adjacent sheds by pendant drops, a result of the dynamic deformation of pendant drops. We numerically investigate the effects of the parameters of pendant drops and the electric field on the dynamic deformation of pendant drops on a 500 kV transformer bushing under extreme rainfall and verify the simulation results by artificial rain experiment. The dynamic deformation of pendant drops is described by solving the Navier-Stokes equations and using the level set method. The results show that the maximum length of the pendant drop increases with the increase in the initial diameter and the initial mass flow rate, respectively, but decreases under the electric field. The main influencing factor on the maximum length of the pendant drop alters with the variation of the initial diameter and the initial mass flow rate in the absence of the electric field, whereas the initial mass flow rate is the unique main influencing factor in the presence of the electric field. Furthermore, the variations of the maximum length and breakup time of the pendant drop are elucidated by the instability of the pendant drop.
Lin Yang; Yijie Sun; Yifan Liao; Zhiqiang Kuang; Yanpeng Hao; Licheng Li; Fuzeng Zhang. Dynamic Deformation of Pendant Drops on the Edge of High-Voltage Bushing Sheds Under Extreme Rainfall. IEEE Access 2020, 8, 118101 -118113.
AMA StyleLin Yang, Yijie Sun, Yifan Liao, Zhiqiang Kuang, Yanpeng Hao, Licheng Li, Fuzeng Zhang. Dynamic Deformation of Pendant Drops on the Edge of High-Voltage Bushing Sheds Under Extreme Rainfall. IEEE Access. 2020; 8 ():118101-118113.
Chicago/Turabian StyleLin Yang; Yijie Sun; Yifan Liao; Zhiqiang Kuang; Yanpeng Hao; Licheng Li; Fuzeng Zhang. 2020. "Dynamic Deformation of Pendant Drops on the Edge of High-Voltage Bushing Sheds Under Extreme Rainfall." IEEE Access 8, no. : 118101-118113.
Icing detection of composite insulators is essential for the security and stability of power grids. As conventional methods have met difficulties in harsh weather, a 110 kV composite insulator with embedded Fiber Bragg Gratings (FBGs) was proposed for detecting glaze icing in this paper. FBG temperature compensation sensors in ceramic tubes were adopted for simultaneous measurement of icicle loads and temperature. Then, temperature calibration experiments and simulated icicle load experiments were carried out to obtain temperature and icicle load characteristics of FBGs. The results showed that temperature sensitivities of FBG strain sensors and FBG temperature compensation sensors were 18.16 pm/°C, and 13.18 pm/°C, respectively. Besides, wavelength shifts were linearly related to icicle loads within the polar angle range of −60° to 60°, and the load coefficient of FBG facing the icicle was -34.6 pm/N. In addition, the wavelength shift generated by several icicles was equal to the sum of wavelength shifts generated by each icicle within the polar angle range of −15° to 15°. Finally, icicles can cause wavelength shifts of FBGs within a big shed spacing. The paper provides a novel icing detection technology for composite insulators in transmission lines.
Jie Wei; Yanpeng Hao; Yuan Fu; Lin Yang; Jiulin Gan; Han Li. Experimental Study on Glaze Icing Detection of 110 kV Composite Insulators Using Fiber Bragg Gratings. Sensors 2020, 20, 1834 .
AMA StyleJie Wei, Yanpeng Hao, Yuan Fu, Lin Yang, Jiulin Gan, Han Li. Experimental Study on Glaze Icing Detection of 110 kV Composite Insulators Using Fiber Bragg Gratings. Sensors. 2020; 20 (7):1834.
Chicago/Turabian StyleJie Wei; Yanpeng Hao; Yuan Fu; Lin Yang; Jiulin Gan; Han Li. 2020. "Experimental Study on Glaze Icing Detection of 110 kV Composite Insulators Using Fiber Bragg Gratings." Sensors 20, no. 7: 1834.
Situations of internal stress in basin insulators inside gas-insulated metal-enclosed switchgear (GIS) can lead to cracks, which can influence the safety and stability of apparatus. However, there is currently no research on internal stress measurements for composites of GIS basin insulators, and only measurements for surface stress. In this paper, an internal stress measurement method for GIS epoxy composite is proposed using an ultrasonic longitudinal through-transmission technique based on the acoustoelastic effect. An internal stress measurement system is developed to investigate the relationship between the uniaxial compressive internal stress and the velocity of the ultrasonic wave vertical to the stress in epoxy composite within a range of 0–70 MPa, and to calculate the acoustoelastic coefficient of epoxy composite. The effects of system delay are eliminated in measuring the propagation time. Some epoxy composite cuboid specimens with similar materials and using a manufacturing process similar to those of 252 kV GIS basin insulators are synthesized, and the uniformity of the internal stress in cuboid specimens is verified by finite element simulation. The results reveal a linear increase of the ultrasonic longitudinal wave velocity with increasing stress. It has been shown that the average acoustoelastic coefficient of GIS epoxy composites, using the longitudinal waves vertical to the stress, is 4.556 × 10−5/MPa. Additionally, the absolute errors of the internal stress measurements are less than 12.397 MPa. This research shows that the ultrasonic method based on the acoustoelastic effect for measuring the internal stress in GIS epoxy composites is feasible.
Zhouyiao Zou; Yanpeng Hao; Fangyuan Tian; Yao Zheng; Weiming He; Lin Yang; Licheng Li. An Ultrasonic Longitudinal Through-Transmission Method to Measure the Compressive Internal Stress in Epoxy Composite Specimens of Gas-Insulated Metal-Enclosed Switchgear. Energies 2020, 13, 1248 .
AMA StyleZhouyiao Zou, Yanpeng Hao, Fangyuan Tian, Yao Zheng, Weiming He, Lin Yang, Licheng Li. An Ultrasonic Longitudinal Through-Transmission Method to Measure the Compressive Internal Stress in Epoxy Composite Specimens of Gas-Insulated Metal-Enclosed Switchgear. Energies. 2020; 13 (5):1248.
Chicago/Turabian StyleZhouyiao Zou; Yanpeng Hao; Fangyuan Tian; Yao Zheng; Weiming He; Lin Yang; Licheng Li. 2020. "An Ultrasonic Longitudinal Through-Transmission Method to Measure the Compressive Internal Stress in Epoxy Composite Specimens of Gas-Insulated Metal-Enclosed Switchgear." Energies 13, no. 5: 1248.
Voids or cracks in basin insulators inside a GIS (gas-insulated metal-enclosed switchgear) could trigger partial discharges or surface flashover under electrical stresses, threatening safe GIS operation. For this paper, some epoxy composite specimens were made from similar materials and manufacturing processes to make 252 kV GIS basin insulators. Some voids with different diameters or cracks with different diameters and orientations were artificially made in the specimens with different thicknesses. An ultrasonic pulse-echo system was set up, and ultrasonic tests were carried out on the specimens with voids or cracks. A method to calculate the depth of a defect was proposed by the propagation time of defect reflected waves. The results showed that a depth of 50 mm, a diameter φ of 2 mm void, and a diameter φ of 1 mm crack in epoxy composite insulation were detected by the ultrasonic system using a 1 MHz transducer.
Fangyuan Tian; Yanpeng Hao; Zhouyiao Zou; Yao Zheng; Weiming He; Lin Yang; Licheng Li. An Ultrasonic Pulse-Echo Method to Detect Internal Defects in Epoxy Composite Insulation. Energies 2019, 12, 4804 .
AMA StyleFangyuan Tian, Yanpeng Hao, Zhouyiao Zou, Yao Zheng, Weiming He, Lin Yang, Licheng Li. An Ultrasonic Pulse-Echo Method to Detect Internal Defects in Epoxy Composite Insulation. Energies. 2019; 12 (24):4804.
Chicago/Turabian StyleFangyuan Tian; Yanpeng Hao; Zhouyiao Zou; Yao Zheng; Weiming He; Lin Yang; Licheng Li. 2019. "An Ultrasonic Pulse-Echo Method to Detect Internal Defects in Epoxy Composite Insulation." Energies 12, no. 24: 4804.
Icing forecasting for transmission lines is of great significance for anti-icing strategies in power grids, but existing prediction models have some disadvantages such as application limitations, weak generalization, and lack of global prediction ability. To overcome these shortcomings, this paper suggests a new conception about a segmental icing prediction model for transmission lines in which the classification of icing process plays a crucial role. In order to obtain the classification, a hierarchical K-means clustering method is utilized and 11 characteristic parameters are proposed. Based on this method, 97 icing processes derived from the Icing Monitoring System in China Southern Power Grid are clustered into six categories according to their curve shape and the abstracted icing evolution curves are drawn based on the clustering centroid. Results show that the processes of ice events are probably different and the icing process can be considered as a combination of several segments and nodes, which reinforce the suggested conception of the segmental icing prediction model. Based on monitoring data and clustering, the obtained types of icing evolution are more comprehensive and specific, and the work lays the foundation for the model construction and contributes to other fields.
Yanpeng Hao; Zhaohong Yao; Junke Wang; Hao Li; Ruihai Li; Lin Yang; Wei Liang. A Classification Method for Transmission Line Icing Process Curve Based on Hierarchical K-Means Clustering. Energies 2019, 12, 4786 .
AMA StyleYanpeng Hao, Zhaohong Yao, Junke Wang, Hao Li, Ruihai Li, Lin Yang, Wei Liang. A Classification Method for Transmission Line Icing Process Curve Based on Hierarchical K-Means Clustering. Energies. 2019; 12 (24):4786.
Chicago/Turabian StyleYanpeng Hao; Zhaohong Yao; Junke Wang; Hao Li; Ruihai Li; Lin Yang; Wei Liang. 2019. "A Classification Method for Transmission Line Icing Process Curve Based on Hierarchical K-Means Clustering." Energies 12, no. 24: 4786.
Composite insulators are widely used in power grids at home and abroad. The anti-pollution flashover performance, hydrophobicity and hydrophobic migration, and pollution flashover mechanism of composite insulators have been the focus of international attention. Temperature is one of the important parameters to describe the flashover of composite insulators. In this paper, the internal temperatures of a composite insulation sample were detected based on FBGs (fiber Bragg gratings). The sample was layered and made of one layer of silicone rubber 3 mm in thickness and one layer of epoxy-GFRP (Glass Fiber Reinforced Plastics) similar to 220 kV composite insulators. Three gratings were embedded in the interface of the two layers between long and short electrodes on the surface of the sample. Temperature calibration tests were carried out on the gratings in the sample. Then, discharges tests were done on the sample with embedded FBGs. Internal temperatures as well as leakage currents were measured, and the arcs process of the discharges on the sample was photographed. The test conditions are as follows: the output voltage was increased by approximately 0.5 kV/s; the equivalent salt deposit density (ESDD) was about 0.5 mg/cm2 and the non-soluble deposit density (NSDD) was about 1.2 mg/cm2.The results show that the internal FBGs could sense the flashover on the surface of the sample. An interface temperature rise caused by the discharges is within 11 °C in this paper. There is a time delay of 1.4 s from the leakage current arise to the temperature rise during the discharges. The arcs always develops from the small electrode to the large electrode on the surface of the sample, the rise process of the internal temperature at the interface under the middle surface position of the two electrodes is significantly different from that near the small electrode, the arcs starting electrode, while similar to that near the large electrode, the flashover electrode.
Yanpeng Hao; Yuan Fu; Jie Wei; Lin Yang; Guiyun Mao; Zhenglin Yang; Licheng Li. Internal Temperature Detections of Contaminated Silicone Rubber Under Discharge Conditions Based on Fiber Bragg Gratings. IEEE Access 2019, 7, 161167 -161174.
AMA StyleYanpeng Hao, Yuan Fu, Jie Wei, Lin Yang, Guiyun Mao, Zhenglin Yang, Licheng Li. Internal Temperature Detections of Contaminated Silicone Rubber Under Discharge Conditions Based on Fiber Bragg Gratings. IEEE Access. 2019; 7 (99):161167-161174.
Chicago/Turabian StyleYanpeng Hao; Yuan Fu; Jie Wei; Lin Yang; Guiyun Mao; Zhenglin Yang; Licheng Li. 2019. "Internal Temperature Detections of Contaminated Silicone Rubber Under Discharge Conditions Based on Fiber Bragg Gratings." IEEE Access 7, no. 99: 161167-161174.
Conventional methods for the online monitoring of icing conditions of composite insulators suffer from difficulties. To solve this issue, a novel method is first proposed to detect glaze icing load via embedding three optical fibers with fiber Bragg gratings (FBGs) into a 10 kV composite insulator. Specifically, FBG temperature compensation sensors were packaged in ceramic tubes to solve strain and temperature cross-sensitivity. Temperature effect experiments and simulated glaze icing load experiments were performed to verify the feasibility of the proposed method. The results show that temperature sensitivities of all FBGs are identical (i.e., 10.68 pm/°C), which achieves a simultaneous measurement of temperature and strain. In addition, the proposed method can detect glaze icing load of the composite insulator above 0.5 N (i.e., 15% of icicle bridged degree) in the laboratory.
Jie Wei; Yanpeng Hao; Yuan Fu; Lin Yang; Jiulin Gan; Zhongmin Yang. Detection of Glaze Icing Load and Temperature of Composite Insulators Using Fiber Bragg Grating. Sensors 2019, 19, 1321 .
AMA StyleJie Wei, Yanpeng Hao, Yuan Fu, Lin Yang, Jiulin Gan, Zhongmin Yang. Detection of Glaze Icing Load and Temperature of Composite Insulators Using Fiber Bragg Grating. Sensors. 2019; 19 (6):1321.
Chicago/Turabian StyleJie Wei; Yanpeng Hao; Yuan Fu; Lin Yang; Jiulin Gan; Zhongmin Yang. 2019. "Detection of Glaze Icing Load and Temperature of Composite Insulators Using Fiber Bragg Grating." Sensors 19, no. 6: 1321.
The hydrophobicity of composite insulators is a great significance to the safe and stable operation of transmission lines. In this paper, a recognition method of the hydrophobicity class (HC) of composite insulators based on features optimization was proposed. Through the spray method, many hydrophobic images of water droplets on the insulator surface at various hydrophobicity classes (HCs) were taken. After processing of the hydrophobic images, seven features were extracted: the number n, mean eccentricity Eav and coverage rate k1 of the water droplets, and the coverage rate k2, perimeter Lmax, shape factor fc, and eccentricity Emax of the maximum water droplet. Then, the maximum value Δxmax, the minimum value Δxmin, and the average value Δxav of the change rate of each feature value between adjacent HCs, and the volatility Δs of each feature value, were used as the evaluation indexes for features optimization. After this features optimization, the five features that are most closely related to the HC were obtained. Lastly, a recognition model of the HC with the five features as input and the seven HCs as output was established. When compared with the spray method and the contact angle method, the correct rate of the proposed recognition method was 98.1% and 95.2%, respectively. The influence of subjective factors on the spray method was effectively overcome.
Lin Yang; Jikai Bi; Yanpeng Hao; Lupeng Nian; Zijun Zhou; Licheng Li; Yifan Liao; Fuzeng Zhang. A Recognition Method of the Hydrophobicity Class of Composite Insulators Based on Features Optimization and Experimental Verification. Energies 2018, 11, 765 .
AMA StyleLin Yang, Jikai Bi, Yanpeng Hao, Lupeng Nian, Zijun Zhou, Licheng Li, Yifan Liao, Fuzeng Zhang. A Recognition Method of the Hydrophobicity Class of Composite Insulators Based on Features Optimization and Experimental Verification. Energies. 2018; 11 (4):765.
Chicago/Turabian StyleLin Yang; Jikai Bi; Yanpeng Hao; Lupeng Nian; Zijun Zhou; Licheng Li; Yifan Liao; Fuzeng Zhang. 2018. "A Recognition Method of the Hydrophobicity Class of Composite Insulators Based on Features Optimization and Experimental Verification." Energies 11, no. 4: 765.
Icing on transmission lines might lead to ice flashovers of insulators, collapse of towers, tripping faults of transmission lines, and other accidents. Shed spacing and shed overhang of insulators are clues for evaluating the probability of ice flashover. This paper researches image-processing methods for the natural icing of in-service glass insulators. Calculation methods of graphical shed spacing and graphical shed overhang are proposed via recognizing the convexity defects of the contours of an icing insulator string based on the GrabCut segmentation algorithm. The experiments are carried out with image data from our climatic chamber and the China Southern Power Grid Disaster (Icing) Warning System of Transmission Lines. The results show that the graphical shed overhang of insulators show evident change due to icing. This method can recognize the most serious icing conditions where the insulator sheds are completely bridged. Also, it can detect bridging positions including the left side, right side, or both sides of the insulator strings in the images.
Yanpeng Hao; Jie Wei; Xiaolan Jiang; Lin Yang; Licheng Li; Junke Wang; Hao Li; Ruihai Li. Icing Condition Assessment of In-Service Glass Insulators Based on Graphical Shed Spacing and Graphical Shed Overhang. Energies 2018, 11, 318 .
AMA StyleYanpeng Hao, Jie Wei, Xiaolan Jiang, Lin Yang, Licheng Li, Junke Wang, Hao Li, Ruihai Li. Icing Condition Assessment of In-Service Glass Insulators Based on Graphical Shed Spacing and Graphical Shed Overhang. Energies. 2018; 11 (2):318.
Chicago/Turabian StyleYanpeng Hao; Jie Wei; Xiaolan Jiang; Lin Yang; Licheng Li; Junke Wang; Hao Li; Ruihai Li. 2018. "Icing Condition Assessment of In-Service Glass Insulators Based on Graphical Shed Spacing and Graphical Shed Overhang." Energies 11, no. 2: 318.
In this paper, the calculation of the conductor temperature is related to the temperature sensor position in high-voltage power cables and four thermal circuits—based on the temperatures of insulation shield, the center of waterproof compound, the aluminum sheath, and the jacket surface are established to calculate the conductor temperature. To examine the effectiveness of conductor temperature calculations, simulation models based on flow characteristics of the air gap between the waterproof compound and the aluminum are built up, and thermocouples are placed at the four radial positions in a 110 kV cross-linked polyethylene (XLPE) insulated power cable to measure the temperatures of four positions. In measurements, six cases of current heating test under three laying environments, such as duct, water, and backfilled soil were carried out. Both errors of the conductor temperature calculation and the simulation based on the temperature of insulation shield were significantly smaller than others under all laying environments. It is the uncertainty of the thermal resistivity, together with the difference of the initial temperature of each radial position by the solar radiation, which led to the above results. The thermal capacitance of the air has little impact on errors. The thermal resistance of the air gap is the largest error source. Compromising the temperature-estimation accuracy and the insulation-damage risk, the waterproof compound is the recommended sensor position to improve the accuracy of conductor-temperature calculation. When the thermal resistances were calculated correctly, the aluminum sheath is also the recommended sensor position besides the waterproof compound.
Lin Yang; Weihao Qiu; Jichao Huang; Yanpeng Hao; Mingli Fu; Shuai Hou; Licheng Li. Comparison of Conductor-Temperature Calculations Based on Different Radial-Position-Temperature Detections for High-Voltage Power Cable. Energies 2018, 11, 117 .
AMA StyleLin Yang, Weihao Qiu, Jichao Huang, Yanpeng Hao, Mingli Fu, Shuai Hou, Licheng Li. Comparison of Conductor-Temperature Calculations Based on Different Radial-Position-Temperature Detections for High-Voltage Power Cable. Energies. 2018; 11 (1):117.
Chicago/Turabian StyleLin Yang; Weihao Qiu; Jichao Huang; Yanpeng Hao; Mingli Fu; Shuai Hou; Licheng Li. 2018. "Comparison of Conductor-Temperature Calculations Based on Different Radial-Position-Temperature Detections for High-Voltage Power Cable." Energies 11, no. 1: 117.