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Shape optimisation of basin insulator for DC gas insulated switchgear/gas insulated transmission lines based on artificial bee colony algorithm

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High Voltage 2024年第2期9卷 275-286页

作者： Yi Luo Shiyi Mao Ju Tang Zijun Pan Cheng Pan State Key Laboratory of Power Grid Environmental Protection School of Electrical Engineering and AutomationWuhan UniversityWuhanChina

The surface charge accumulation on the basin insulator is a particular problem in high-voltage direct current(HVDC)gas insulated switchgears(GIS)and gas insulated trans-mission lines(GIL),which restricts the development and application of extra/ultra high-voltage(EHV/UHV)*** surface charge distribution and anti-flashover performance are closely related to the insulator *** obtain the optimal basin insulator,a shape optimisation model based on artificial bee colony algorithm was established,and the minimisation objective functions based on capacitive(initial)electric field distribution and resistive(steady-state)electric field distribution were respectively *** optimisation results of the two objective functions were calculated,and the electric field and charge distribution on the surface of the insulator before and after optimisation were evaluated and compared using the simulation *** results indicated that the optimisation based on the capacitive electric field can significantly inhibit the surface charge accumulation,and the optimised insulator can significantly reduce the surface normal electric field and make the distribution of the tangential electric field more uniform,and the maximum tangential electric field can be reduced by 10%;the optimisation based on resistive electric field can achieve similar results,but requires more computational *** on the results,the‘anti-charge’basin insulator structure suitable for the DC field was given.

关键词： insulator artificial charge

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Hygrothermal ageing performance of high temperature vulcanised silicone rubber and its degradation mechanism

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High Voltage 2023年第6期8卷 1196-1205页

作者： Yu Deng Bo Peng Zheyuan Liu Yujun Du Songsong Zhou Jinghua Liu Xinzhe Yu Jun Zhou State Key Laboratory of Power Grid Environmental Protection(China Electric Power Research Institute) BeijingChina State Grid Corporation of China BeijingChina

High temperature vulcanised silicone rubber(SR)has excellent hydrophobicity and thus is widely applied both in indoor and outdoor *** to the analysis of different experimental ageing tests and field investigation of SR,temperature and humidity are considered to be the fundamental factors during *** ageing was proposed in this study to simulate the chalking state of the SR,finally leading to the irreversible degradation far below the thermal decomposition *** variation of morphology,hardness and polydimethylsiloxane(PDMS)content was quantified during the yearlong hygrothermal ageing *** is implied that the gradual process of whitening and hardening are accompanied by the decline of the PDMS ***,ageing delamination in SR and its degradation mechanism were proposed.

关键词： thermal mechanism rubber

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Positive corona discharge of rod-plate electrodes in high-speed airflow

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High Voltage 2025年第2期10卷 337-350页

作者： Qiang Wu Yu Wang Zhengxian Du Zeliang Wu Yeqiang Deng Xishan Wen School of Electrical Engineering and Automation Wuhan UniversityWuhanChina State Key Laboratory of Power Grid Environmental Protection Wuhan UniversityWuhanChina

The characteristics of positive corona discharge of rod electrode in high-speed airflow are studied in this *** experiments were carried out in a wind tunnel with a maximum flow speed of 100 m/s in a dark *** discharge voltage and current were recorded and the corona patterns were captured by a digital single lens reflex(DSLR)camera during the experiment.A discharge transition in rod electrode from streamer corona to mixed streamer-glow corona,and finally to stable glow discharge was observed with the voltage *** increase of airflow speed resulted in a decrease of each corona inception *** streamers will be suppressed and shifted towards the upwind side,while the glow layer will be promoted and shifted towards the downwind side in low and upwind side in high *** glow corona current and the voltage show a quadratic function and the higher the airflow speeds,the bigger the coefficient of square of *** distributions of peaks,pulse widths and interval times of streamer pulses were analysed,showing good correspondence with the streamer *** measurements were explained by combining particle transport and local air pressure distribution.

关键词： rod plate electrodes stable glow discharge streamer corona corona patterns wind tunnel rod electrode positive corona discharge discharge transition

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Failure mechanism of metallized film capacitors under DC field superimposed AC harmonic:From equipment to material

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High Voltage 2024年第5期9卷 1081-1089页

作者： Zhiyuan Li Yihan Zhou Xuguang Wang Hongbo Liu Lu Cheng Wenfeng Liu Shengtao Li Jiang Guo Yang Xu State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'anChina State Key Laboratory of Power Grid Environmental Protection WuhanChina State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjingChina

This study focuses on the degradation behaviour of metallised film capacitors,which are the essential components for the stability of converter valves in flexible ultra-high voltage direct current(HVDC)transmission *** systematic experimentation,we investigated the failure mechanisms of MFCs under HVDC fields with superimposed harmonics,considering both equipment and material *** experiments subjected capacitors to 500 h of ageing under two conditions:a DC/AC-superimposed field with a constant DC component of 290 kV/mm and an AC ripple rate varying from 12%to 28%,and a control group aged solely under a DC *** findings indicate that capacitors aged under the DC/AC-superimposed field exhibited shorter lifespans and more significant capacitance loss than those aged under only the DC *** difference in performance is primarily attributed to the distinct electrode loss behaviours observed under each ageing condition,which are key factors in the capacitors'capacitance ***,the biaxially oriented polypropylene films in the DC-aged samples showed more severe deterioration,characterised by more noticeable molecular chain scission and reduced breakdown strength,compared to those aged under the DC/AC superimposed *** difference is partly due to the moderate temperature increase caused by harmonics,which benefits the aggregation structure,and partly to the reduced molecular structure damage from the AC field.

关键词： film harmonics field

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Discharge characteristics of leader inception and development under 10 m long air gap—experimental observation and simulation results

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High Voltage 2023年第6期8卷 1151-1160页

作者： Changzhi Peng Xuzhu Dong Yanpu Zhao Zhijun Li Yu Zheng Xuekai Pei Lei Liu Bing Luo School of Electrical Engineering and Automation Wuhan UniversityWuhanChina State Key Laboratory of Environmental Protection for Power Grid State Grid Corporation of ChinaWuhanChina Electric Power Research Institute China Southern Power GridGuangzhouChina

The physical mechanism of leader formation and development is not well *** this study,we present experimental and simulation results obtained with a 10 m long air gap discharge.A 10 m outdoor discharge experiment is carried out to obtain the current,voltage,and optical image during the leader discharge *** different impulse voltages were applied to the rod‐plane *** measured current is used as an input for a plasma model,then the temperature and electric field could be *** simulation results show that the temperature of the streamer stem during the dark period may exceed 2000 *** addition,the critical charge required for leader initiation can be as low as 0.27μC for a 10 m air *** channel temperature is relatively stable in the process of leader development,which is maintained at about 4500 *** electron density is about 0.5–3�1020 m-3,and the discharge channel conductivity fluctuates in the range of 1–10 S/m for the leader current between 1 and 2 A.A long dark period is tended to be associated with a higher injected charge by the first *** is inferred that the voltage increments during the dark period play an important role in promoting streamer‐to‐leader transition,except for temperature and the injected charge.

关键词： discharge characteristics maintained

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Characteristics of perfluoromethyl vinyl ether:A new eco-friendly alternative gas for SF_(6)

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High Voltage 2024年第3期9卷 509-517页

作者： Song Xiao Yijiang Chen Mingjun Tang Shuangshuang Tian Haoran Xia Yifan Wang Ju Tang Yi Li Xiaoxing Zhang State Key Laboratory of Power Grid Environmental Protection School of Electrical Engineering and AutomationWuhan UniversityHubeiChina Key Laboratory for High-Efficiency Utilization of Solar Energy and Operation Control of Energy Storage System School of Electrical and Electronic EngineeringHubei University of TechnologyWuhanChina

The exploration of eco-friendly insulating gas to substitute the most potent greenhouse gas sulphur hexafluoride(SF6)has consistently garnered significant ***,the au-thors evaluated the feasibility of utilising perfluoromethyl vinyl ether(PMVE,C_(3)F_(6)O)as a new branch of eco-friendly insulating gas for the first *** primary dielectric and stability characteristics of PMVE regarding AC breakdown,partial discharge,dielectric recovery,and decomposition properties were revealed under various gas pressure and electrical field *** was found that PMVE demonstrated superior dielectric strength,with the AC breakdown and PD inception voltage(PDIV)1.10 and 1.14 times that of pure SF_(6).Furthermore,the dielectric strength of PMVE exhibits stability even after undergoing 100 cycles of AC breakdowns,and there is no observable formation of solid precipitation on the electrode *** discharge decomposition of PMVE mainly generates fluorocarbon(CF_(4),C_(2)F_(6),C_(3)F_(6),C_(3)F_(8),etc.)and ***,the exceptional insulation stabilityandno absence of solidprecipitation featuresendow PMVE tobe utilised as a new eco-friendly gas for SF_(6)-free gas-insulated equipment.

关键词： surface dielectric vinyl

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Audible Noise Performance of High Voltage AC Conductor Bundles at an Altitude of 226lm

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CSEE Journal of power and Energy Systems 2023年第6期9卷 2447-2455页

作者： Wangling He Baoquan Wan Shilong Huang Yunpeng Liu Jiangong Zhang Xiao Han North China Electric Power University Baoding 071000China China Electric Power Research Institute(State Key Laboratory of Power Grid Environmental Protection) Wuhan 430074China

Extra or ultra-high voltage transmission lines can exhibit strong corona discharge and generate severe audible noise(AN)at high altitudes,which has become a critical limiting factor for power lines ***,the AN data of bundle conductors at high altitudes are very rare,which cannot adequately support the power utilities to make reasonable conductor *** this paper,a sound pressure level(SPL)of 14 types of bundle conductors is investigated by using an ultra-high-voltage(UHV)corona cage(8 m×8 m×35 m)at an altitude of 2216 m,where the bundle numbers between 4 and 12 and the conductor types are used in 500 kV,750 kV or 1000 kV power transmission *** a large number of valuable AN data are obtained;the influences of bundle numbers and sub-conductor diameters on an acoustic power density level(LPWL)are analyzed;and an A-weighted LPWL calculation method is *** addition,by comparing the AN data obtained from the low-altitude area(altitude:23 m),the AN altitude correction factor is concluded,and the influences of conductor parameters and the surface electric field strength on correction factors are *** results obtained in this paper can provide important data for the construction of high-altitude AC power lines.

关键词： AC power lines audible noise corona discharge high altitude

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Assessment on gas-polyethylene terephthalate solid interface partial discharge properties of C4F7N/CO_(2)gas mixture for eco-friendly gas insulating transformer

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High Voltage 2024年第1期9卷 35-45页

作者： Song Xiao Yifan Wang Chenhua Ren Haoran Xia Yue Zhao Jingzi Qin Xiaoxing Zhang Yi Luo Yi Li State Key Laboratory of Power Grid Environmental Protection School of Electrical Engineering and AutomationWuhan UniversityWuhanHubeiChina Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina State Grid Anhui Electric Power Company Anhui Electric Power Research Institute HefeiAnhuiChina Hubei Engineering Research Center for Safety Monitoring of New Energy and Power Grid Equipment School of Electrical and Electronic EngineeringHubei University of TechnologyWuhanHubeiChina

The eco-friendly insulating gas perfluoroisobutyronitrile(C_(4)F_(7)N)is potentially used in gas-insulated transformers(GIT)to replace sulphur hexafluoride(SF_(6)).However,evaluation of the long-term insulation reliability and gas–solid interface discharge decomposition characteristics of the gas–solid film insulation structure in GIT is *** authors simulated the gas–solid film insulation structure in GIT and explored the interface partial discharge(PD)characteristics of C4F7N/CO_(2)gas mixture with polyethylene terephthalate(PET).The effect of gas pressure,mixing ratio on gas–solid interface gas decomposition,PET degradation was investigated,and the interaction mechanism was *** is found that the interface PD generated three degradation regions on a PET *** gas–solid interface reaction in the electrode contact region and the discharge development trace was significantly higher than that of halation *** content of gas decomposition products decreases with the increase of gas pressure and the PD intensity of SF6-PET is inferior to that of C_(4)F_(7)N/CO_(2)under the same *** results provide reference for the development and application of C_(4)F_(7)N/CO_(2)based GIT.

关键词： interface solid insulation

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Rhodium-Catalyzed Asymmetric Hydrogenation of Tetrasubstitutedα,β-Unsaturated Amides:Efficient Access to Chiralβ-Amino Amides

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Chinese Journal of Chemistry 2024年第21期42卷 2641-2646页

作者： Bing Jiao Fangyuan Wang Hui Lv State Key Laboratory of Power Grid Environmental Protection/Hubei Key Lab on Organic and Polymeric Optoelectronic Materials/Engineering Research Center of Organosilicon Compounds&Materials Ministry of Education/Key Laboratory of Biomedical Polymers of Ministry of Education&College of Chemistry and Molecular SciencesWuhan UniversityWuhanHubei430072 China

The first asymmetric hydrogenation of acyclic tetrasubstitutedα,β-unsaturated amides has been achieved by using Rh/DuanPhos complex as a catalyst,delivering chiralβ-amino amides with two contiguous chiral centers in excellent yields and high enantioselectivities(up to 99%yield,96%ee),which provides efficient and concise access to valuableβ-amino amide *** gram-scale reaction and efficient transformation ofβ-amino amide toβ-amino acid andβ-amino cyanide demonstrated the utility of this methodology.

关键词： Asymmetric hydrogenation β-Amino amides Asymmetric catalysis Contiguous chiral centers Rhodium Amines Reduction Enantioselectivity

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Dispersion characteristics of switching transients from large‐scale experiments in a 1100 kV gas insulated switchgear circuit

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High Voltage 2023年第6期8卷 1253-1263页

作者： Zihan Teng Weijiang Chen Jiangong Zhang Baoquan Wan Jun Zhao Kejie Li Zhenghai Liao Zheyuan Gan State Key Laboratory of Power Grid Environmental Protection China Electric Power Research InstituteWuhanChina State Grid Corporation of China BeijingChina School of Electrical Engineering and Automation Hefei University of TechnologyHefeiChina

The switching operation of gas insulated switchgear(GIS)disconnector will produce multiple random spark discharges between the gas gaps of the *** spark discharge can be affected by various random factors,such as trapped charge on the load side,the initial operating phase,gap distance and operating speed of the disconnector,leading to dispersion *** present,some studies have mentioned this dispersion,but its impact is still unclear due to the lack of experimental data,resulting in a deviation between the simulation results and the measured *** this study,thousands of switching operations were carried out based on the 1100 kV full‐scale GIS circuit in Wuhan ultra‐high voltage alternating current Test *** maximal information coeffi-cient analysis,linear regression fitting and other statistical methods were used to discuss the dispersion characteristics of very fast transient overvoltage(VFTO)and transient enclosure voltage(TEV)from large‐scale experimental *** results show that the dispersion of VFTO and TEV in amplitude aspects both increase gradually as the breakdown voltage increases,with the maximum difference of five times of TEV amplitude at normalised breakdown *** terms of frequency characteristics,the dispersion of different fre-quency components in TEV is always greater than that of VFTO,especially for the high‐frequency ***,by comparing the frequency characteristics of TEV at different positions,we notice that the dispersion is almost independent of the spatial po-sition but only determined by the randomness of spark *** discoveries reveal the importance of the dispersion in switching transients and make up for the lack of theoretical understanding of the correlation among them.

关键词： characteristics transient breakdown

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