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Influence of Bird Droppings Channel on Electric Field Distribution Characteristics for Catenary Positive Feeder insulator string Under Windy Conditions

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IEEE ACCESS 2024年 12卷 68747-68756页

作者： Xu, Jinyang Ma, Jianqiao Ren, Limiao Lanzhou Jiaotong Univ Coll Automat & Elect Engn Lanzhou 730070 Peoples R China

Under windy conditions, air currents induce changes in the shape and trajectory of bird-dropping channels. Therefore, it is crucial to examine the impact of the bird droppings channel on the electric field distribution under such conditions. This study established a simulation experiment system to model the bird droppings channel's morphology under windy conditions. The experiments have identified three typical morphologies of the bird droppings channel under windy conditions: quasi-linear, wavy, and fan-shaped. A simulation model of the bird droppings channel around the insulator string of the catenary feeder was also established, analyzing the influence law of three typical bird-dropping channel forms on the local electric field intensity distribution characteristics of catenary feeder insulator string under windy conditions. The simulation results reveal that the quasi-linear bird droppings channel causes a distorted area of the electric field on the insulator surface concentrated at the head of the channel. The electric field intensity increases with the angle of the channel offset, and the closer the channel is to the insulator edge, the stronger the electric field intensity at the head. The wavy bird droppings channel directly short-circuits the 1# insulator, resulting in the most severe distortion of the 1# insulator's surface electric field. The influence of the fan-shaped bird droppings channel on the surface electric field is mainly concentrated at the joints between the insulator cap, shed, and air. The study results indicate that, under windy conditions, the wavy-shaped channel has the most severe impact on the voltage distribution of the insulator string, whereas the quasi-linear and fan-shaped bird droppings channels exhibit nearly the same impact as under ideal working conditions. The results of this paper can provide a reference for the analysis of the causes of the bird dropping channel flashover fault of catenary feeder under windy conditions.

关键词： Windy conditions bird droppings channel morphology catenary positive feeder insulator string electric field distribution

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A Cloud Edge Collaborative Intelligence Method of insulator string Defect Detection for Power IIoT

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IEEE INTERNET OF THINGS JOURNAL 2021年第9期8卷 7510-7520页

作者： Song, Chunhe Xu, Wenxiang Han, Guangjie Zeng, Peng Wang, Zhongfeng Yu, Shimao Chinese Acad Sci Shenyang Inst Automat Key Lab Networked Control Syst Shenyang 110016 Peoples R China Chinese Acad Sci Inst Robot Shenyang 110016 Peoples R China Chinese Acad Sci Inst Intelligent Mfg Shenyang 110016 Peoples R China Fujian Univ Technol Fujian Key Lab Automot Elect & Elect Drive Fuzhou 350118 Peoples R China Hohai Univ Dept Informat & Commun Syst Changzhou 213022 Peoples R China

Using unmanned aerial vehicles (UAVs) for equipment condition monitoring is an important application of Industrial Internet of Things (IIoT), and the limited energy is the key factor to restrict the application of UAV. In order to reduce the computational load for intelligence computing of UAV, this article proposes a cloud edge collaborative intelligent method for object detection, and applies it to insulator string recognition defect detection in the power IIoT. First, the impact of the extremely large aspect ratio of object on the detection accuracy and the computational load is analyzed, then the cloud edge collaborative intelligent method for insulator string detection and defect recognition is presented, in which on the UAV side a low cost method is proposed for estimating possible directions of insulator strings, and on the cloud side, an effective method is proposed for insulator string defect detection. The experimental results show the effectiveness of the proposed algorithm. To the best knowledge of us, this article is the first work to analyze the impact of the extremely large aspect ratio of insulator string on the detection accuracy and the computational load.

关键词： insulators Unmanned aerial vehicles Feature extraction Support vector machines Image edge detection Cloud computing Training Artificial intelligence defect recognition edge computing Industrial Internet of Things (IIoT) insulator string

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Shape and electric performance improvement of an insulator string using particles swarm algorithm

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2020年第2期14卷 198-205页

作者： Doufene, Dyhia Bouazabia, Slimane Haddad, Abderrahmane Univ Sci & Technol Houari Boumediene Elect & Ind Syst Lab LSEI Bab Ezzouar Algeria Cardiff Univ Sch Engn Adv High Voltage Engn Res Ctr Cardiff CF24 3AA Wales

In this study, a particle swarm optimisation (PSO) algorithm coupled with finite-element method (FEM) is implemented to improve the performance of a cap-and-pin insulator by reducing the value of maximum electric field strength. Two goals are set in this work: (i) optimisation of the tangential electric field distribution and magnitude (which is taken as the objectif function to be minimised) to reduce the risk of flashover due to surface pollution, and (ii) reduction of the creepage distance (by adopting adequate constraints) leading to a reduction of the surface area and consequently a decrease in the insulator weight. The investigation is divided into two parts;first, one-unit insulator is optimised with which a chain is constructed, and its performance compared with the reference insulator string. The second part considers a whole chain of four-unit insulator whose performance is optimised and compared to that of a reference insulator string. The main finding of this work indicates that, if an insulator string is constructed using an optimised cap-and-pin unit, the performance of the so-formed string is also optimised. The optimisation of a complete string leads to practically the same performance as that of a string obtained by assembling optimised insulator units.

关键词： electric fields insulators finite element analysis flashover ceramic insulators particle swarm optimisation insulator contamination surface area insulator weight one-unit insulator four-unit insulator insulator string cap -pin unit complete string optimised insulator units electric performance improvement particles swarm algorithm particle swarm optimisation algorithm finite-element method -pin insulator maximum electric field strength tangential electric field distribution objectif function

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Leakage Current Response Mechanism of insulator string string With Ambient Humidity on Days Without Rain

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IEEE ACCESS 2019年 7卷 55229-55236页

作者： Wang, Jianguo Xi, Yanjun Fang, Chunhua Cai, Li Wang, Jianping Fan, Yadong Wuhan Univ Sch Elect Engn & Automat Wuhan 430072 Hubei Peoples R China China Three Gorges Univ Coll Elect Engn & New Energy Yichang 443002 Peoples R China

The leakage current, which is influenced by the operating voltage, the surface contamination, and environmental variables, is one of the most basic online monitoring parameters for the surface contamination status of insulators. However, the impact of temperature and humidity on leakage current have not been expressed concisely nor distinguished according to sunny and rainy weather. In this paper, based on leakage current online monitoring data, the time-domain waveforms of leakage current of an insulator string in Shenzhen, China, were compared with those of the ambient temperature and humidity. Results indicate that the leakage current presents a saddle-shaped curve on days without rain, and that there is a remarkable positive correlation between leakage current and humidity as well as a negative correlation between leakage current and temperature. In a short period (several days) without rain, as long as the relative humidity keeps constant, the leakage current would vary insignificantly, whereas it may vary in a wide range at the same temperature. Moreover, the functional relation mathematical model I = a * e(b)*(RH) between the first harmonic component of leakage current and the relative humidity is presented, inferring that the insulator string leakage current depends mainly on the ambient relative humidity in a day without rain.

关键词： Leakage current ambient temperature relative humidity insulator string on-line monitoring response mechanism

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A Fault Diagnosis Method of insulator string Based on Infrared Image Feature Extraction and Probabilistic Neural Network 10

A Fault Diagnosis Method of Insulator String Based on Infrar...

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10th International Conference on Intelligent Computation Technology and Automation (ICICTA)

作者： Xiao, Lijun Mao, Qiang Lan, Penghao Zang, Xiaochun Liao, Zhiwei Beijing Univ Posts & Telecommun State Key Lab Networking & Switching Technol Beijing 100876 Peoples R China Guangdong Power Grid Co Ltd Zhuhai Power Supply Bur Zhuhai 519000 Peoples R China South China Univ Technol Guangzhou 510640 Guangdong Peoples R China

ISBN: (纸本)9781538612309

In view of the close relationship between insulator fault and surface temperature distribution, a detection method for insulator string is proposed combined infrared image segmentation and artificial neural network, which is based on the analysis of infrared image processing and fault diagnosis of artificial neural network. Firstly, the steel cap and the disk of insulator string are extracted according to their length characteristics, and then the temperature characteristics are calculated, finally, the fault diagnosis model of insulator string is established by probability neural network (PNN) according to the integral temperature distribution rule of a string insulator and the heating law of fault insulator. The K-means clustering method is introduced to eliminate the bad data and improve the accuracy of diagnosis when the temperature characteristics are calculated. The validity and accuracy of the proposed method are verified in the application of 500kV substation insulator string state detection.

关键词： insulator string Fault Detection Image Segmentation K-Means Cluster Probability Neural Network

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Investigations on AC pollution flashover performance of insulator string under different non-uniform pollution conditions

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IET GENERATION TRANSMISSION & DISTRIBUTION 2016年第2期10卷 437-443页

作者： Zhang, Zhijin You, Jinwei Wei, Donghong Jiang, Xingliang Zhang, Dongdong Bi, Maoqiang Chongqing Univ State Key Lab Power Transmiss Equipment & Syst Se Chongqing 400044 Peoples R China State Grid Chongqing Elect Power Co Elect Power Res Inst Chongqing 401121 Peoples R China

Observations of contamination tests showed that, the contamination distribution of insulators is usually uneven. In this study, the solid layer method was used to imitate different non-uniform pollution conditions and the AC pollution flashover tests of 7-unit insulators were carried out. The results indicate that the increase of uneven pollution degree J from 1 to 15 will give a 39% raise of U-50 under non-uniform pollution on top and bottom surfaces, a 23% decrease for fan-shaped non-uniform pollution and a 21% higher U-50 with ring-shaped non-uniform pollution. A higher occupation ratio (k) of leeward side will reduce U-50 under fan-shaped non-uniform pollution and a bigger radius R of heavy polluted area has certain effect on U-50 for ring-shaped non-uniform pollution. The U-50 and salt deposit density still can be expressed by the negative power function, and non-uniform pollution conditions and J have great effect on a, but less impact on n. The correction equations of different non-uniform pollution conditions are obtained and the relative errors are acceptable. The research has certain reference significance for the design and selection of AC transmission line external insulation.

关键词： insulator string pollution flashover iodine AC power transmission lines insulators sectorial relative errors ANNULAR negative power

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A Set of Models for Investigation of Voltage Distribution Along Suspension insulator string

A Set of Models for Investigation of Voltage Distribution Al...

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IEEE North-West-Russia-Section Young Researchers in Electrical and Electronic Engineering Conference (ElConRusNW)

作者： Antonov, Alexey S. Glushkov, Daniil A. Kropotuhin, Sergey Y. Ural Fed Univ Dept High Voltage Tech 19 Mira St Ekaterinburg 620002 Russia

ISBN: (纸本)9781509004454

Suspension insulator string is widely used as insulator structures in high voltage overhead power lines. Power frequency voltage of feed line is distributed along string elements in unequal amounts due to parasitic capacities (on ground and wire). Grading rings arrangement close to current-conducting elements is one of the most effective ways for voltage grading. The results of investigation of voltage distribution along insulator string based on the following models set are presented in the article: real string in high voltage laboratory, string physical model based on lumped elements, mathematical model in software package. Two-dimensional axially symmetric model of insulator string based on finite element analysis was developed in ActiveField software package. The results of optimality calculation for selection of grading ring arrangement height are presented and analyzed. Comparison and analysis of theoretical and experimental data were carried out on the base of investigation results.

关键词： voltage distribution insulator string suspension insulator porscelain/toughened glass insulator grading ring

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Investigation of the DC Arc Propagation of insulator string and Its Performance at Low Air Pressure

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IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2015年第6期22卷 3244-3252页

作者： Zhang, Zhijin Zhang, Dongdong Zheng, Qiang Li, Xing Jiang, Xingliang Chongqing Univ Sch Elect Engn State Key Lab Power Transmiss Equipment & Syst Se 174 Shazheng St Chongqing 400044 Peoples R China

Air pressure affects the electrical performance of polluted insulator. The dc pollution flashover process of 7-unit XP-160 insulator string under low air pressure was presented by laboratory tests in this paper. During the tests, the flashover voltage and the critical flashover current were measured. Also, based on the insight of insulator flashover process, the length of discharge path, the arc propagation velocity and arc radius under different air pressure were investigated and measured. The research results indicate that, the position of arcing point is stochastic and multipoint arcing phenomenon exists. Surface arc will levitate and develop into air-gap arc under low air pressure. The length of discharge path is related to air pressure and pollution degree, and it is always shorter than the total creepage of insulator string. The leakage current, the arc shape and arc propagation velocity, are also related to air pressure. In this study, it was measured that the arc radius (r(a)) varied from 1.5 to 3.5 mm, and the characteristic exponent describing the influence of air pressure on arc radius (m) varied from -0.35 to -0.65. The research results are of some significance for revealing the mechanism of flashover and discharge performance of arcs.

关键词： dc low air pressure insulator string pollution flashover arc propagation

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DIDNet: An End-to-End Directional insulator Detection Network Based on Direction Field 7th

DIDNet: An End-to-End Directional Insulator Detection Networ...

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7th Chinese Conference on Pattern Recognition and Computer Vision

作者： Wu, Yuxiang Sun, Shuifa Wei, Ning Coll Comp & Informat Technol Hubei Key Lab Intelligent Vis Based Monitoring Hy Yichang 443002 Hubei Peoples R China China Three Gorges Univ Coll Comp & Informat Technol Yichang 443002 Hubei Peoples R China

ISBN: (纸本)9789819784929;9789819784936

insulator strings exhibit strong directional characteristics in UAV images and have relatively long spatial spans. Therefore, traditional anchor box-based methods struggle to accurately locate their spatial features. In this paper, we model the linear features of insulator strings by first describing the position of the central axis segment of the insulator string using endpoints at both ends. Then, a direction field on the insulator space is established to encode the repetitive texture features of the insulator string itself. Based on this model, an end-to-end convolutional neural network is constructed to generate a set of proposed line segments by estimated keypoints. These proposed lines are then encoded using a feature map enhanced with the direction field, enabling the learning of the texture features of the insulator string. Experimental results demonstrate that the proposed algorithm framework achieves more accurate directional positioning of insulator strings under the DIOU (Direction Intersection over Union) metric.

关键词： insulator string direction field channel attention

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Analysis of Overvoltage and Backflashover with Different Transmission Line Models

Analysis of Overvoltage and Backflashover with Different Tra...

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IEEE SoutheastCon Conference on Engineering the Future

作者： Guevara, Jesus E. Colqui, Jaimis S. L. Pissolato Filho, Jose Univ Estadual Campinas Sch Elect & Comp E Campinas SP Brazil

ISBN: (纸本)9798350317107;9798350317114

Most research on the lightning overvoltage and backflashover phenomenon caused by direct lightning strikes use EMT programs considering the J. Marti model to represent transmission lines. Additionally, Carson's equations are used to compute the earth-return impedance. However, these equations disregard ground displacement current and assume that soil electrical properties are independent of frequency. Due to these disregards, simulations can produce incorrect findings and possibly even skip backflashover into existing insulator strings. In order to carry out the study of lightning overvoltage and backflashover, a real overhead transmission line in 440 kV was analyzed, getting results that there is backflashover when using the Pettersson transmission line model, even in two phases. However, it does not occur when Carson and Nakagawa models are used in some cases of lightning. Furthermore, considering high values of electrical resistivity of the ground will increase the lightning overvoltage in the insulator string. For example, when this value increases from 1000 to 10,000 Omega(sic)m, the lightning overvoltage increases by 249%.

关键词： Lightning overvoltage backflashover transmission line insulator string lightning current

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