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Intelligent identification method of insulation pull rod defects based on intactness-aware Mosaic data augmentation and fusion of YOLOv5s

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High Voltage 2024年第5期9卷 1171-1182页

作者： Changyun Li Yuze Hua Yilin Liu Kai Liu Sanyi Zhang College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdaoChina College of Electrical Engineering Southwest Jiaotong UniversityChengduChina Institute of Information Engineering Chinese Academy of SciencesBeijingChina

The authors introduce the intactness-aware Mosaic data augmentation strategy,designed to tackle challenges such as low accuracy in detecting defects in insulation pull rods,limited timeliness in intelligent analysis,and the absence of a comprehensive database for information on insulation pull rod *** proposed strategy incorporates the YOLOv5s algorithm for detecting defects in insulation pull ***,the YOLOv5s network was constructed,and a dataset containing photos of insulation pull rods with white spots,fractures,impurities,and bubble flaws was compiled to capture images of *** research presented a data enhancement approach to improve the images and establish a dataset for insulation pull rod *** YOLOv5s algorithm was applied for both training and testing purposes.A comparative analysis was conducted to assess the detection performance of YOLOv5s against a conventional target detector for identifying defects in insulation pull ***,the utility of Mosaic's data augmentation technique,which incorporates intactness awareness,was evaluated to enhance the accuracy of identifying insulation pull rod *** research findings indicate that the YOLOv5s algorithm is employed for intelligent detection and precise localisation of *** intactnessaware Mosaic data augmentation strategy significantly improves the accuracy of detecting faults in insulation pull *** YOLOv5s model used achieves a performance index mAP@0.5:0.95 of 0.563 on the test set,distinct from the training set *** a threshold of 0.5,the mAP@0.5 score is 0.904,indicating a substantial improvement in both detection efficiency and accuracy compared to conventional target detection *** approaches for identifying defects in insulation pull rods are introduced.

关键词： Mosaic insulation defects

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Mitigation of Deane and Hamill phenomenon in gallium nitride high-voltage power supply for electric propulsion system application

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High Voltage 2024年第1期9卷 252-265页

作者： Minghai Dong Hui Li Shan Yin Kye Yak See Yingzhe Wu Xiong Xin School of Aeronautics&Astronautics University of Electronic Science and Technology of ChinaChengduChina School of Electrical&Electronic Engineering Nanyang Technological UniversitySingaporeSingapore School of Automation Engineering University of Electronic Science and Technology of ChinaChengduChina Innoscience(Shenzhen)Semiconductor Co.Ltd. ShenzhenChina

The step-up resonant converters are widely adopted to provide high voltage in kV-level for electric propulsion system due to their high efficiency,low mass,modularisation,and high-power *** bipolar Cockcroft-Walton voltage multiplier(BiCWVM)is a major circuit that steps up the voltage in the resonant ***,the diode nonlinearity in BiCWVM can introduce self-sustained quasi-periodic oscillations in the voltage and current waveforms,which is commonly known as the Deane and Hamill(DH)*** oscillation can lead to higher magnetic loss and control failure,and it is more likely to present in the gallium nitride-based converter due to the highfrequency *** authors aim to investigate and mitigate the DH phenomenon systematically so that proper mitigation can be *** facilitate the investigation,the circuit before the BiCWVM in the converter is derived and modelled as a voltage source v_(m)and a series inductor L_(sy).Also,the reverse recovery process of the diode in the BiCWVM can be represented by a piecewise-linear(PWL)model,with the simplified circuit and PWL model,the relationship between voltage and current under different operating conditions can be determined with *** relationship allows to understand the mechanism of diode reverse recovery in BiCWVM that leads to DH ***,a hybrid-/full-silicon carbide(SiC)design is proposed to mitigate the DH phenomenon,which is verified experimentally for a 300-kHz,5-W,20-V/1.5-kV GaN-based step-up resonant converter.

关键词： power resonant high

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Research on the Time of Fire Initiation Caused by Tree Line Faults Under 35kV Transmission Lines 14

Research on the Time of Fire Initiation Caused by Tree Line ...

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14th International Conference on Power and Energy Systems, ICPES 2024

作者： Yang, Haohan Chen, Tianxiang Zeng, Yi Wang, Zheng The college of Nuclear Technology and Automation Engineering Chengdu University of Technology Cheng Du China

ISBN: (纸本)9798350391329

In recent years, forest fires caused by transmission line tree line faults occur frequently, transmission line tree line faults affect the safety and reliability of power grid operation, a serious threat to the safety of natural resources and people's property. In this paper, for the 35kV transmission line tree line faults caused by hill fire, built a 35kV line tree line fault experimental platform, in the capacitance current of 248 mA and 132 mA conditions, respectively, selected bamboo, pine and cedar three typical trees as a research sample, to carry out the three kinds of trees tree line fault fire time experiments. The burning phenomena, charring channels, and infrared images of different trees were recorded and analyzed, and the corresponding laws were drawn up to summarize the longest and shortest fire starting times of different capacitance currents and different trees. The research in this paper can provide technical reference for the development of measures to prevent fire caused by tree line faults in 35kV transmission lines. © 2024 IEEE.

关键词： Infrared imaging

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Experimental Study on the Effect of Temperature on tan δ Measurement of 110 kV Voltage Transformer 14

Experimental Study on the Effect of Temperature on tan δ Me...

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14th International Conference on Power and Energy Systems, ICPES 2024

作者： Gu, Hong Chen, Tianxiang Cai, Lehui Jiang, Zhuofeng The college of Nuclear Technology and Automation Engineering Chengdu University of Technology Cheng Du China

ISBN: (纸本)9798350391329

Voltage transformer as a substation important equipment, assuming the role of measurement, control and protection. Equipment in the operation process is susceptible to temperature and other factors that cause insulation defects, need to carry out regular insulation preventive testing. In this paper, we take 110 kV series-type voltage transformer as the research object, and use four different wiring methods to explore the changes of tanδ value and capacitance under different ambient temperatures, insulating oil temperatures, and insulating oil moisture conditions, to verify the applicability and reasonableness of the relevant values in the Regulations, and to provide an effective basis for the series-type voltage transformer to determine the insulation faults of the equipment through the tanδ value. The results show that the tanδ value increases with the rise of temperature under different wiring methods, while the capacitance is basically unchanged;the end shielding method is the most sensitive to the moisture of insulating oil under different temperature conditions;when the insulation is normal, the conventional inverse wiring is more sensitive to the temperature change;when the insulation is faulty, the conventional positive wiring is more sensitive;to determine whether there are insulation defects of voltage transformers should be measured by the tanδ value in lower temperature as the main criterion, and the Kegulations' will be used to determine whether there are insulation defects of the series type voltage transformer through the tanδ value. Judgment of whether the voltage transformer insulation defects should be measured at lower temperatures tanδ as the main criterion, Kegulations' in the relevant tanδ value criterion should be adjusted in a timely manner. © 2024 IEEE.

关键词： Capacitance

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Three-Dimensional Vector Cube Decomposition-Based Power Allocation for Multisource Inverter-Fed PMSM Drives

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IEEE Transactions on Power Electronics 2025年第8期40卷 10705-10716页

作者： Luo, Kehan Zhou, Dehong Zhang, Zhao Zou, Jianxiao Zhou, Xue University of Electronic Science and Technology of China School of Automation Engineering Chengdu611731 China University of Electronic Science and Technology of China Shenzhen Institute for Advanced Study Shenzhen518000 China

The multisource inverter (MSI)-fed motor drive is an attractive solution for hybrid electric vehicles. However, the design of the modulation scheme for the MSI is a challenging task since the desired motor control and the flexible power allocation between energy sources under unbalanced dc links should be realized simultaneously. In view of this, this article proposes a three-dimensional vector cube decomposition (3DVCD)-based power allocation strategy for the MSI to achieve flexible power allocation and desired motor control under unbalanced dc links. In the proposed 3DVCD scheme, the reference vector is synthesized in two symmetrical subcubes instead of the uneven three-dimensional voltage vector cube, which simplifies the modulation scheme with unbalanced dc links. By proportionally decomposing the reference vector as two subvectors and mapping them into two symmetrical subcubes, the additional degree of freedom of the power flow control of sources without affecting the motor control is obtained. Based on this, the power allocation between each source is realized by directly adjusting the decomposition factor of the reference vector. Besides, the theoretical power allocation range with the proposed scheme is analyzed. Experimental tests are conducted to validate the effectiveness and superiority of the proposed scheme. © 1986-2012 IEEE.

关键词： Vectors

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Research on the Characteristics of Leakage Current Changes in Tree Line Faults of 10Kv Distribution Lines 14

Research on the Characteristics of Leakage Current Changes i...

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14th International Conference on Power and Energy Systems, ICPES 2024

作者： Wang, Zheng Chen, Tianxiang Yang, Haohan Zeng, Yi The college of Nuclear Technology and Automation Engineering Chengdu University of Technology Cheng Du China

ISBN: (纸本)9798350391329

There are numerous cases of forest fires caused by tree line faults in distribution lines, and it is of great significance to study the characteristic signals when tree line faults occur to prevent mountain fire accidents. In this paper, through theoretical analyses and the construction of real experimental platform, we studied the change rule of leakage current when single-phase tree line fault occurs in different trees. Through the single-phase tree line fault experiment, the relationship between leakage current and tree species, capacitive current to ground and water content when different trees touch the line is studied. The results of the study show that: the occurrence of single-phase tree line fault leakage current for the first time to reach the maximum value of time and tree species, the first time to reach the maximum value of the water content of trees and ground capacitance related. © 2024 IEEE.

关键词： Water content

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Enhancing Safety in Nonlinear Systems: Design and Stability Analysis of Adaptive Cruise Control

IEEE Transactions on Intelligent Vehicles

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IEEE Transactions on Intelligent Vehicles 2024年 1-11页

作者： Yang, Fan Li, Haoqi Lv, Maolong Hu, Jiangping Zhou, Qingrui Ghosh, Bijoy K. School of Automation Engineering University of Electronic Science and Technology of China Chengdu China Air Force Engineering University Xian China Qianxuesen Lab China Academy of Space Technology Beijing China

The safety of autonomous driving systems, particularly self-driving vehicles, remains of paramount concern. These systems exhibit affine nonlinear dynamics and face the challenge of executing predefined control tasks while adhering to state and input constraints to mitigate risks. However, achieving safety control within the framework of control input constraints, such as collision avoidance and maintaining system states within secure boundaries, presents challenges due to limited options. In this study, we introduce a novel approach to address safety concerns by transforming safety conditions into control constraints with a relative degree of 1. This transformation is facilitated through the design of control barrier functions, enabling the creation of a safety control system for affine nonlinear networks. Subsequently, we formulate a robust control strategy that incorporates safety protocols and conduct a comprehensive analysis of its stability and reliability. To illustrate the effectiveness of our approach, we apply it to a specific problem involving adaptive cruise control. Through simulations, we validate the efficiency of our model in ensuring safety without compromising control performance. Our approach signifies significant progress in the field, providing a practical solution to enhance safety for autonomous driving systems operating within the context of affine nonlinear dynamics. IEEE

关键词： Adaptive cruise control

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Characterization of the Effect of Different Flame Clusters on Gap Leakage Current Under 10Kv Line 14

Characterization of the Effect of Different Flame Clusters o...

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14th International Conference on Power and Energy Systems, ICPES 2024

作者： Zeng, Yi Chen, Tianxiang Wang, Zhen Yang, Haohan Chengdu University of Technology The college of Nuclear Technology and Automation Engineering Cheng Du China

ISBN: (纸本)9798350391329

In recent years, wildfires in the corridors of transmission and distribution lines have occurred frequently, posing a serious threat to the stable operation of the power grid. To study the influence of flame cluster number on the leakage current characteristics of gaps in 10 kV lines, experiments were conducted on the discharge characteristics of a 12 cm wire-board gap under different vegetation flame cluster conditions. The variations in leakage current amplitude under different capacitive current conditions were analyzed, clarifying two discharge forms under flaming conditions. The results indicate that the leakage current in single and multiple cluster vegetation flame conditions is inversely correlated with capacitive current and shows a negative correlation with the ash content of vegetation. Under capacitive currents of 1A and 5A, breakdown occurs in the gap under straw flame conditions, attributed to the highest ash and burning particle content in the straw. This demonstrates that temperature is not the primary factor affecting gap breakdown under straw flame conditions, with ash content being dominant. The findings provide technical references for using electrical signals from lines to warn of wildfires beneath and analyze the causes of incidents. © 2024 IEEE.

关键词： Premixed flames

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Experimental Study of Flame Impedance Characteristics under 35 kV Line 2

Experimental Study of Flame Impedance Characteristics under ...

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2nd Asia Power and Electrical technology Conference, APET 2023

作者： Meng, Wang Tianxiang, Chen Chaoxu, Zeng Sen, Yang Longshan, Yang Long, Chen College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu China

ISBN: (纸本)9798350359428

Hill fire hazards on transmission and distribution lines due to various factors affect the safe operation of the lines. The current study does not consider the effect of ground capacitance current on fire impedance characteristics under the line. This paper takes 35 kV line under the mountain fire flame impedance characteristics as the test object, build different to ground capacitance of the mountain fire test platform, put forward the mountain fire ground fault theoretical model, through simulated line under the mountain fire test on the flame completely bridged gap order eucalyptus, shrubs and straw flame impedance characteristics of curve fitting, verify the vegetation mountain fire triggered by the line single-phase grounding is a high resistance ground, research and analysis of the vegetation flame impedance characteristics of the impact mechanism. Experimental research shows that the occurrence of mountain fire fault line fault degree and ground capacitance current is positively correlated;flame temperature is one of the main factors affecting flame impedance, flame impedance and flame temperature does not strictly show a negative correlation;different vegetation types triggered by mountain fire flame impedance characteristics vary greatly, arc discharge will seriously weaken the vegetation flame insulation characteristics, flame completely bridged gap stage before and mid-term flame impedance of the main influencing factors are flame temperature and flame height, flame completely bridged gap stage late flame impedance of the main influencing factors into the ash content of vegetation. The study of vegetation flame impedance characteristics can provide technical reference for transmission and distribution lines to prevent line failures caused by hill fires. © 2023 IEEE.

关键词： Fires

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Study on the Influence of Temperature on Tanδ Measurement of 110kV Cascade Voltage Transformer 2

Study on the Influence of Temperature on Tanδ Measurement o...

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2nd Asia Power and Electrical technology Conference, APET 2023

作者： Longshan, Yang Tianxiang, Chen Shuyue, Wang Xun, Wang College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu China

ISBN: (纸本)9798350359428

Cascade voltage transformers (hereinafter referred to as CTV) are widely used in power grids, and a good insulation condition is a prerequisite for their safe and reliable operation. 110kV CTV tan δ can be affected by changes in environmental factors (such as temperature and humidity), and sometimes the tanδ can be abnormal or even fail to reflect the actual state of the equipment. This paper takes a JCC6-110 CTV which has been operated for many years as the research object, and makes a comprehensive and detailed study on the influence of temperature on CTV tanδ, and researches the change of CTV tanδ under different temperature conditions, proposes the CTV insulation equivalent circuit model, obtains tanδ and capacity data through different wiring methods and derives the model parameters, and establishes the insulation equivalent circuit model influenced by temperature factors. The insulation equivalent circuit model with the influence of temperature factors is proposed, and the method of correcting tanδ to the standard atmospheric conditions is proposed. The model was simulated using MATLAB/Simulink software to verify the correctness of the insulation equivalent circuit model considering the effect of temperature on tanδ under fault conditions, and the model can be applied to the conversion and correction of the effect of temperature on CTV tanδ during field testing. © 2023 IEEE.

关键词： Timing circuits

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