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Integrated Experimental and Simulation Investigation of Breakdown voltage Characteristics Across Electrode Configurations in SF_(6) Circuit Breakers

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Journal of Electronic research and Application 2024年第4期8卷 133-142页

作者： Bo Guan Qi Yu Qingpeng Yuan Shiwen Chen Lailin Chen Su Guo Peilong Zhu Xiangshan research institute Ningbo University of TechnologyNingbo 315799China Lotus Cars Ningbo 315336China Naisen Electric Ningbo 315712China

This study investigates the breakdown voltage characteristics in sulfur hexafluoride(SF6)circuit breakers,employing a novel approach that integrates both experimental investigations and finite element *** a sphere-sphere electrode configuration,we meticulously measured the relationship between breakdown voltage and electrode gap distances ranging from 1 cm to 4.5 *** simulations,conducted using COMSOL Multiphysics,mirrored the experimental setup to validate the model’s accuracy through a comparison of the breakdown voltage-electrode gap distance *** simulation results not only aligned closely with the experimental data but also allowed the extraction of detailed electric field strength,electric potential contours,and electric current flow curves at the breakdown voltage for gap distances extending from 1 to 4.5 *** the analysis,the study explored the electric field and potential distribution at a constant voltage of 72.5 kV for gap distances between 1 to 10 cm,identifying the maximum electric field strength.A comprehensive comparison of five different electrode configurations(sphere-sphere,sphere-rod,sphere-plane,rod-plane,rod-rod)at 72.5 kV and a gap distance of 1.84 cm underscored the significant influence of electrode geometry on the breakdown ***,the research contrasts the breakdown voltage in SF6 with that in air,emphasizing SF6’s superior insulating *** investigation not only elucidates the intricate dynamics of electrical breakdown in SF6 circuit breakers but also contributes valuable insights into the optimal electrode configurations and the potential for alternative insulating gases,steering future advancements in high-voltage circuit breaker technology.

关键词： SF6 circuit breaker Breakdown voltage Electrode configurations COMSOL simulation Electrical insulation

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Influence of imidazolium ionic liquids as organic filler dispersant on electrical properties of chitin/epoxy composites

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high voltage 2024年第4期9卷 930-938页

作者： Kai Yin Qihong Fan Jing Li Taqi ur Rahman Tianyin Zhang Ashish Paramane Xiangrong Chen School of Information and Electrical Engineering Hangzhou City UniversityHangzhouChina College of Electrical Engineering Zhejiang UniversityHangzhouChina State Grid Tianjin Power Chengnan District Supply Company TianjinChina Electrical Engineering Department National Institute of TechnologySilcharAssamIndia

Ionic liquid(IL)as the dispersant can help disperse the organic nanofillers to improve the performance of epoxy resin ***,the effect of IL on the electrical properties of epoxy composites is not well *** comprehensive study consists of the preparation,material characterisation and systematical investigation of electrical properties of 1-Butyl-3-methylimidazole hexafluorophosphate-modified chitin fibre/epoxy *** findings show that introducing IL into a chitin/epoxy composite can minimise porosity defects and improve the compatibility between filler and ***,a high concentration of IL induces severe charge injection into chitin/epoxy composites and internal electric field *** addition of 0.75%–1.5%mass fraction IL results in maximum enhancement in the AC breakdown strength of the chitin/epoxy composite(by~71%)compared with the non-IL *** nonlinear conductivity and non-uniform charge injection phenomena of IL-modified composites can be attributed to the movement of radicals and anions due to the decomposition of *** this study,it is highly expected that the organic filler dispersion in the epoxy matrix can be optimised by tuning IL to improve the insulation properties.

关键词： composites composite filler

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Defects and failure types of solid insulation in gas‐insulated switchgear:In situ study and case analysis

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high voltage 2022年第1期7卷 158-164页

作者： Yunqi Xing Zhiwen Wang Lin Liu Yuan Xu Yang Yang Shan Liu Fusheng Zhou Shun He Chuanyang Li State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjinChina Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province Hebei University of TechnologyTianjinChina School of Electric Power South China University of TechnologyGuangzhouChina high voltage institute China Electric Power Research InstituteBeijingChina Simpson Querrey institute Northwestern UniversityEvanstonIllinoisUSA HVDC Transmission Technology Department Globe Energy Interconnection Research InstituteBeijingChina Electric Power research institute China Southern Power GridGuangzhouChina high voltage institute Yunnan Institute of Electrical ScienceYunnanChina institute of Material Science University of ConnecticutStorrsConnecticutUSA

The gas‐insulated switchgear(GIS)has been widely used in modern ultra‐high voltage ***,once it fails,its fully enclosed feature brings challenges in its diagnosis and *** the failure rate of GIS due to insulator failure has been increasing in recent years,it is necessary and important to understand the commonly existing defects presented in the ***,the manufacturing process of GIS insulators is intro-duced *** defect types commonly existing in the insulator are *** failure of GIS due to insulator defects that occurred in recent years are reviewed and *** content in this study is useful for engineers and scientists to study on the GIS solid insulation defects and their failure mechanisms.

关键词： (GIS) insulation solid

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A NEW HYBRID THERMOCHEMICAL CYCLE FOR PRODUCTION OF HYDROGEN FROM WATER

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Science in China,Ser.B 1986年第7期29卷 709-717页

作者：廖晓垣 research institute of Applied Technology wuhan university

A new hybrid cycle to produce hydrogen from water, which consists of a thermochemical reaction （3） and an electrochemical reaction （4）, has been devised.2KNO3+I2→2KI+2NO+2O2, （3）2NO+3/2 O2+2KI+H2O→2KNO3+I2+H2. （4）The change in free energy of the reaction （3） decreases as temperature rises. and the temperature, at which the △G° is zero, is about 950 K. The electrochemical reaction （4） could be divided intoanode 2I-→I2+2e- （7）andcathode 2H++2e-→H2 （8）in electrolysis cell with an ion-exchange resin. So, the standard equilibrium decomposition voltage of the reaction （4） is 0.54 *** preliminary experimental investigations were carried out. The yields of the reaction （3） increase as the temperature rises, and KNO3 is converted into KI casily and rapidly, when reacting with gaseous iodine above 1000 K. The polarizations of the electrolysis reaction were small. The sum of the equilibrium decomposition voltages and overvoltages—0.56, 0.65 and 0.78 V at 100, 500 and 1000 mA·cm-2, respe

关键词： A NEW HYBRID THERMOCHEMICAL CYCLE FOR PRODUCTION OF HYDROGEN FROM WATER

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A novel dimmable LED driver with soft-start and UVLO circuits

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Journal of Semiconductors 2015年第2期36卷 135-143页

作者：江金光谭高建张泽宇周细凤 GNSS research Center Wuhan University School of Physics and Technology Wuhan University Suzhou institute Wuhan University School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

A fully integrated LED driver based on a current mode PWM boost DC-DC converter with constant output current is proposed. In order to suppress the inrush of current and the overshoot voltage at the start up state, a soft-start circuit is adopted. Additionally, to adjust the LED brightness without color variation over the full dimming range and achieve high efficiency, a PWM dimming circuit is presented. Furthermore, to keep the loop stability of the LED driver, an internal slope compensation network is designed to avoid the sub-harmonic oscillation when the duty cycle exceeds 50%. Finally, a UVLO circuit is adopted to improve the reliability of the LED driver against the input voltage changing. The LED driver has been fabricated with a standard 0.5/xm CMOS process, and only occupies 1.21 × 0.76 mm^2. Experimental results show that the brightness of the LED can be adjusted by an off- chip PWM signal with a wide adjusting range. The inductor current and output current increase smoothly over the whole load range. The chip is in the UVLO condition when the input voltage is below 2.18 V and has achieved about 137 μs typical start-up time.

关键词： LED driver DC-DC converter UVLO soft-start PWM dimming

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Simulation Analysis of Transmission-Line Impedance Transformers for Petawatt-Class Pulsed Power Accelerators

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Plasma Science and Technology 2011年第4期13卷 490-496页

作者：呼义翔孙风举黄涛邱爱慈丛培天王亮平曾江涛李岩张信军雷天时 State Key Laboratory of Electrical insulation and Power Equipment Xian Jiaotong University Northwest institute of Nuclear Technology

Based on the transmission line code TLCODE, a 1D circuit model for a transmission- line impedance transformer was developed and the simulation results were compared with those in the literature. The model was used to quantify the efficiencies of voltage-transport, energy- transport and power-transport for a transmission-line impedance transformer as functions of ψ （the ratio of the output impedance to the input impedance of the transformer） and Г （the ratio of the pulse width to the one-way transit time of the transformer） under a large scale of m （the coefficient of the generalized exponential impedance profile）. Simulation results suggest that with the increase in Г, from 0 to ∞, the power transport efficiency first increases and then decreases. The maximum power transport efficiency can reach 90% or even higher for an exponential impedance profile （m = 1）. With a consideration of dissipative loss in the dielectric and electrodes of the transformer, two representative designs of the water-insulated transformer are investigated for the next generation of petawatt-class z-pinch drivers. It is found that the dissipative losses in the electrodes are negligibly small, below 0.1%, but the dissipative loss in the water dielectric is about 1% to 4%.

关键词： dissipative loss transmission line code (TLCODE) transport efficiency transmission line impedance transformer

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Effect of Frequency on Degradation in BOPP Films Under Repetitively Pulsed voltage

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1280-1290页

作者： Chuansheng Zhang Yu Feng Fei Kong Bangdou Huang Cheng Zhang Tao Shao Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China university of Chinese Academy of Sciences Beijing 100049China

Operating conditions of film capacitors are complex,and the problem of film insulation failure caused by repetitively pulsed voltage is becoming ever *** of the film under repetitively pulsed voltage cannot be accurately evaluated by the average breakdown electric *** this paper,the effects of pulsed electric field and pulse repetition frequency on the breakdown in biaxially oriented polypropylene(BOPP)films are *** phases of BOPP degradation are proposed based on the voltage amplitude,i.e.,maintenance(M),decline(D),and near-zero(N).Evolution of the BOPP film from degradation to breakdown at different frequencies is ***,transition of discharge mode and elemental composition of the film are *** results show continuous heat generation under repetitive microsecond pulses is the dominant factor for degradation of BOPP *** number of applied pulses and the repetitive stressing time decrease exponentially with increase of *** research can be contributed to the safe and reliable operation of capacitors.

关键词： Aging breakdown film capacitor polypropylene repetitive pulse

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The influence of the sand-dust environment on air-gap breakdown discharge characteristics of the plate-to-plate electrode

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Science China(Physics,Mechanics & Astronomy) 2010年第3期53卷 458-464页

作者： HE Bo1, ZHANG Gang1, CHEN BangFa1, GAO NaiKui1, LI YaoZhong2, PENG ZongRen1 & JIN HaiYun1 1 State Key Laboratory of Electrical insulation and Power Equipment, Xi’an Jiaotong university, Xi’an 710049, China 2 Xinjiang Electric Power research institute, Urumqi 830011, China State Key Laboratory of Electrical insulation and Power Equipment Xi’an Jiaotong University Xi’an China Xinjiang Electric Power research institute Urumqi China

The experiments of plane-plane gap discharge was carried out in an environment of artificial sandstorm. By comparing and analyzing the differences in gap breakdown voltage between the sand & dust environment and clean air, some problems were investigated, such as effects of wind speed and particle concentration on the breakdown voltage, differences of gap discharge characteristics between the dust & sand medium and the clean air medium. The results showed that compared with the clean air environment, the dust & sand environment had a decreased gap breakdown voltage. The longer the gap distance, the greater the voltage drop; the breakdown voltage decreased with the increase of particle concentration in flow. With the increase of wind speed, the breakdown voltage decreased at the beginning and rose afterwards. The results of the paper may helpful for further research regarding the unidentified flashover and external insulation characteristics of the HV power grid in the dust & sand environment.

关键词： external insulation air-gap breakdown sand-dust flow simulation experiment

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Decay-like fracture diagnosis of composite insulator based on small sample virtual expansion and radar graph mapping

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high voltage 2023年第2期8卷 347-357页

作者： Ben Shang Youping Fan Yuqing Zhang Lei Yang Zijiang Wang Yating Zhang Zian Zeng Jianyi Guo School of Electrical Engineering and Automation Wuhan UniversityWuhanChina College of Electrical Engineering and New Energy China Three Gorges UniversityYichangChina China Electric Power research institute WuhanChina

Due to the complexity of test procedures and the high cost of measurements,the mechanism of the decay-like fracture is unclear,which brings hard concepts and the small sample ***,it is intractable to establish accurate data-driven *** solve the above mentioned problems,this paper proposes a data-driven modeling method based on radar graph mapping models and virtual sample generation(Radar-VSG).The main idea of the proposed method is to construct and select the most appropriate input features by using radar graph mapping,and to generate virtual samples by using the local outlier factor based on the isometric feature mapping algorithm(Isomap-LOF).To verify the effectiveness of our approach,a set of 27 training samples and 127 testing samples from China Southern Power Grid was *** results suggested the accuracy was up to 100%after adding more than 27 virtual samples,with a 4.75%*** the model has the best generalisation ability for 270 virtual samples,with the root mean square error of *** with support vector machine and four advanced VSG methods,the proposed Radar-VSG can achieve better performance.

关键词： mapping virtual fracture

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Digital/Analog Simulation Platform for Distributed Power Flow Controller Based on ADPSS and dSPACE

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CSEE Journal of Power and Energy Systems 2021年第1期7卷 181-189页

作者： Aihong Tang Zhijian Lu Huiyuan Yang Xinpeng Zou Yong Huang Xu Zheng the School of Automation Wuhan University of TechnologyWuhan 430070Hubei ProvinceChina the State Grid Hubei Economic&Technology research institute Wuhan 430077Hubei ProvinceChina

Distributed power flow controller,which is among the most powerful distributed flexible transmission equipments,is still only in the stage of the oretical research and digital *** order to promote the engineering demonstration of a distributed power flow controller,it is urgent to establish a digital/analog simulation platform that supports closed-loop real-time simulation of a distributed power flow *** this paper,the electromagnetic transient model of a distributed power flow controller is established on ADPSS(advanced digital power system simulator).The rapid control prototype realized by dSPACE is connected to ADPSS to form a digital/analog simulation platform for a distributed power flow *** a voltage control and power flow control simulation of the test system with a distributed power flow controller,the correctness and effectiveness of the constructed simulation platform are verified,which provides a new way for the verification of the new theory of a distributed power flow controller.

关键词： ADPSS digital/analog simulation platform distributed power flow controller dSPACE rapid control prototype

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