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Effects of Corona Discharge from the Grounding Tip on Charge Evolution of Wall Bushing

IEEE Transactions on power Delivery 2025年第3期40卷 1682-1693页

作者： Bai, Zheng Zhou, Yuanxiang Zhang, Yunxiao Huang, Xin Xie, Xiongjie Liu, Taiwei Tsinghua University State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Beijing100084 China Electric Power Research Institute State Key Laboratory of Power Grid Environmental Protection Wuhan430204 China

Manufacturers consider that the grounding tip near the wall bushing flange is a potentially important factor in several sheath perforation accidents. Taking a ±100 kV true type SF6 gas-insulated bushing as a typical wall bushing, this paper tests the impact of the nearby grounding tip on the charge accumulation. Based on the experiment results, we propose the three-dimensional nonlinear conduction model to unravel the charge accumulation process and the three-dimensional corona ion migration model to clarify the corona process. It is concluded that the consumption of gas ions leads to the nonlinear charge relaxation process. When the corona of grounding tip incepts, numerous ions are generated, forming an "overcharge" phenomenon. The electric field at the insulator-sheds interface and the SF6-insulator interface increases compared to the normal condition, with non-uniform distribution along the circumferential direction. Material inhomogeneity amplifies electric field distortion and creates insulation weaknesses, making insulation aging more likely and potentially leading to a slowly developing electrical tree breakdown process. The length of the needle tip affects the duration of the corona effect;an excessively long needle tip can cause a sustained corona discharge. This research provides a foundation for bushing accidents analysis and operation reliability improvement. © 1986-2012 IEEE.

关键词： Bushings

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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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A New Method for the Aging Evaluation of Oil-Paper Insulation Using η-Butanol and Methanol

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CSEE Journal of power and Energy systems 2024年第2期10卷 717-726页

作者： Jianyi Wang Yuanxiang Zhou Jun Liu Zhaowei Wang Song Bai Jiayu Lu Department of High Voltage China Electric Power Research InstituteBeijing 100192China State Key Laboratory of Power Grid Environmental Protection Beijing 100192China Electrical Engineering Department Tsinghua UniversityBeijing 100084China Solar Storage Division of State Key Lab of Power System and Generation Equipment School of Electrical EngineeringXinjiang UniversityUrumqi 830047China State Grid Wuwei Electric Power Supply Company Wuwei 733000China

To improve the accuracy and efficiency of the aging life prediction and assessment of transformer oil-paper insulation,and to make up for the deficiencies of traditional characterizers,such as 2-furfural,carbon monoxide,and carbon dioxide,a method for the simultaneous determination of methanol,ethanol,n−propanol,and η-butanol in oil with a single injection is established by headspace-gas chromatography-mass *** measured results show that the determination limits of the four alcohol characterizers can be controlled to 10μg/kg *** on this method,the change patterns of the above four alcohols with thermal aging time and degree of polymerization are obtained through thermal aging experimental ***,η-propanol,and η-butanol in oil indicate nearly linear correlations with thermal aging time and degree of polymerization,similar to that of *** analyzing 52 sets of measured data of 500 kV EHV transformers in operation,η-butanol is found to have excellent performance,and a new method to evaluate the aging state of oil-paper insulation employing η-butanol and methanol is proposed along with the aging attention value *** measured data of 500 kV EHV transformers in operation indicate that the combination of η-butanol and methanol as the preferred characterizers can effectively compensate for the shortcoming of traditional characterizers in the early stages of aging,and the feasibility of the method is *** possible pathways for the generation of η-butanol by cellulose cleavage during the aging of oil-paper are proposed from the chemical structure of cellulose.

关键词： Aging characterization determination method methanol η-butanol oil-paper insulation 500 kV transformers

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The bubble formation characteristics of oil‐paper insulation and its influence on insulation performance

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High Voltage 2023年第5期8卷 1030-1040页

作者： Yiyi Zhang Qianlun Du Wenchang Wei Wenqiang Wang Gang Wang Yansong Liu Qing Xie Guangxi Power Transmission and Distribution Network Lightning Protection Engineering Technology Research Center Guangxi UniversityNanningChina Electric Power Research Institute Guangxi Power Grid Co.Ltd.NanningChina State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University BaodingChina

Engineering experience shows that for transformers with long service life and serious moisture exposure,the inter‐turn paper insulation inside the winding will precipitate bubbles under the condition of electric field and conductor heating,which will endanger the equipment *** order to explore the influence factors of bubbles formation in the moist insulating paper of transformers,based on the existing research on the influence of moisture content and gas dissolution in transformer oil,this study further considers the influence of air pressure(AP)and electric field and establishes an experimental platform to change the air pressure and electric field,thereby studying the formation characteristics of bubbles in oil‐paper *** results show that air pressure and electric field can affect the initial temperature,volume,and shape of bubble *** 0 to−0.05 MPa for air pressure,the initial temperature of bubble generation decreased by 41℃,its maximum two‐dimensional projected area increased by 418.4%with more severe distortion,and the breakdown voltage *** the AC voltage applied on the needle plate electrode increased from 0 to 10 kV,the initial temperature of bubble formation increased by 29℃,and the maximum two‐dimensional projection area increased by 336.6%.

关键词： bubble insulation characteristics

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Research for MMC Topology of power Conversion system and Test for Control Performance Based on RTDS 4

Research for MMC Topology of Power Conversion System and Tes...

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4th International Conference on Smart Grid and Energy Internet, SGEI 2024

作者： Yang, Zaixin Jian, Xusheng Liu, Xiaokai Liu, Feng Inner Mongolia Key Laboratory of Smart Grid of New-type Power System Institute of Relay Protection Inner Mongolia Electric Power Science & Research Institute Hohhot China

ISBN: (纸本)9798350368314

With the widespread application of PCSs in power system for large-scale new energy, it is of great significance to study the new topology structure and control strategy of power conversion system (PCS). In this paper, a MMC topology of PCS is studied and MMC digital model is established. The control strategy is proposed to enable PCS to operate continuously for 10 minutes under 0.2 pu. grid voltage. Therefore, a novel RTDS for PCS controller testing platform is established. power control testing, frequency response testing, and voltage ride through testing of the actual hardware of PCS controller is completed. The correctness and effectiveness of the control strategy of the new hybrid energy storage multifunctional controller is verified. ©2024 IEEE.

关键词： Electric power system control

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Wide Bandwidth Rogowski Coil Overvoltage Measurement system Using the Tap of the Transformer Bushing 4

Wide Bandwidth Rogowski Coil Overvoltage Measurement System ...

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4th International Conference on Advanced Electrical and Energy systems, AEES 2023

作者： Dai, Min Wang, Lei Fan, Zhenxing Liu, Hao Ma, Guoming State Key Laboratory of Power Grid Environmental Protection Wuhan China North China Electric Power University State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing China

ISBN: (纸本)9798350342659

Bushings are one of the vulnerable parts to overvoltage effects in power transformers. Therefore, it is significant to investigate the wide bandwidth overvoltage measurement system for the transformer bushing. In this paper, a wide bandwidth overvoltage measurement system using the tap of the bushing was developed. Two Rogowski coils were utilized as the main component to address the wide frequency range and large variation in ground current at the tap of the bushing. Rogowski coils with a frequency threshold of 5kHz were designed to measure the low-frequency and high-frequency components of the overvoltage separately. An integrator was used to reconstruct the overvoltage on the top of the bushing. Lightning overvoltage and operational overvoltage produced by a bushing experimental platform were measured, verifying the excellent performance of the proposed sensor. © 2023 IEEE.

关键词： Taps

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Study on the Catalytic Degradation of Strong Greenhouse Gas SF6 Using a Two-Dimensional Metal Organic Framework 5

Study on the Catalytic Degradation of Strong Greenhouse Gas ...

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5th IEEE International Conference on Dielectrics, ICD 2024

作者： Zhu, Kexin Lv, Langlang Chen, Guangzhi Jiang, Hua Wang, Xiangyu Dai, Liangjun Zeng, Fuping School of Electrical Engineering and Automation Wuhan University State Key Laboratory of Power Grid Environmental Protection Wuhan430072 China Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing400044 China

ISBN: (纸本)9798350308976

With the continuous development of sustainable and renewable energy sources, the catalytic degradation of SF6, a strong greenhouse gas, is receiving increasing attention. In this article, we provide a reference for the selection of SF6 thermal catalysts by simulating the adsorption and decomposition processes of SF6 on two-dimensional metals with different metal modifications. Based on DFT (density functional theory), simulate energy changes and charge transfer during adsorption and decomposition processes. The absence of band gaps in the energy band structure of Cu-CN, Mo-CN and Tc-CN implies their metallic character, which can be attributed to the effective orbital interaction between the benzene ring and MN4. In addition, there is a strong chemisorption between the CN structures of Cr, Mn and Ru and SF6 with significant bond length changes, charge transfer. The CN structures of these three metals have better potential to catalyze SF6 © 2024 IEEE.

关键词： Bond length

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Effects of Cross-Linking Density on the Breakdown Characteristics of Silicone Gels for power Device Encapsulation 5th

Effects of Cross-Linking Density on the Breakdown Characteri...

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5th International Symposium on Plasma and Energy Conversion, iSPEC 2023

作者： Zhu, Kexin Zeng, Fuping Chen, Rirong Lv, Langlang Jiang, Hua Chen, Guangzhi Hubei State Key Laboratory of Power Grid Environmental Protection School of Electrical Engineering and Automation Wuhan University Hubei Wuhan430072 China Hubei Key Laboratory of Power Equipment & System Security for Integrated Energy School of Electrical Engineering and Automation Wuhan University Hubei Wuhan430072 China

ISBN: (纸本)9789819722440

Silicone gels are widely used as a high-performance polymer insulating material in the packaging of high-voltage, high-power devices. However, under long-term thermal stress conditions, silicone gels undergo cross-linking reactions, and the degree of cross-linking increases with the aging degree. In order to study the potential relationship between the aging degree and the crosslink density, this paper builds the AC and DC withstand voltage test platform, by changing the ratio of the specimen preparation, to obtain the silicone gel specimens with different crosslink density, and carries out the negative polarity under the role of the rod-plate electrode DC breakdown test, and draws the Weibull distribution diagram. The study shows that the increase of cross-linking density leads to the decrease of the breakdown voltage of the organosilicon gel, and the change of the cross-linking density of the organosilicon gel due to thermal aging is an important means by which it affects the breakdown voltage of the organosilicon gel. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Organosilicon

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A Flexible Antenna Array Design for Microwave Energy Transmission 17th

A Flexible Antenna Array Design for Microwave Energy Transmi...

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17th Annual Conference of China Electrotechnical Society, CES 2022

作者： Chen, Jinghan Guo, Siwei Nie, Yongjie Liu, Siyang Wang, Ping State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University Chongqing China Yunnan Key Laboratory of Green Energy Electric Power Measurement Digitalization Control and Protection Yunnan Power Grid Co. Ltd. Kunming China

ISBN: (纸本)9789819904075

Microstrip antenna as a kind of receiver front-end equipment of microwave energy transmission system, which plays an important role on the overall transmission efficiency of the system. Conventional solid metal antennas have poor mechanical properties and are susceptible to plastic deformation and cracks under external forces, which will degrade their performance. Gallium-indium alloy (EGaIn), which is liquid at room temperature, has similar electrical properties to copper and can recover itself after bending, which can make up for the shortcoming of solid-state antennas;Polyethylene naphthalate two formic acid glycol ester (PEN) is an organic polymer material, which has similar electrical properties and superior mechanical properties to conventional materials. Based on the above two materials, this paper proposes a microstrip antenna array based on flexible materials, which can endure a wide range of mechanical deformation and has better ductility and mechanical toughness. The simulation results indicate that the proposed antenna array can operate at 2.45 Hz and achieve 90% efficiency of conventional antennas, which can better meet the demand of microwave energy transmission. © 2023, Beijing Paike Culture Commu. Co., Ltd.

关键词： Microstrip antennas

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A diluent protective organic additive electrolyte of hydrophilic hyperbranched polyester for long-life reversible aqueous zinc manganese oxide batteries

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Frontiers of Materials Science 2023年第2期17卷 65-78页

作者： Hengxin Xu Song Yang Yufeng Chen Junle Xiong Shengtao Zhang Fang Gao Zhengyong Huang Hongru Li College of Chemistry and Chemical Engineering Chongqing UniversityChongqing 400044China Chongqing Kunding Environmental Protection Technology Co.Ltd.Chongqing 400044China State Key Laboratory of Power Transmission Equipments and System Security and New Technology Chongqing UniversityChongqing 400044China

hydrophilic hyperbranched polyester(poly(tetramethylol acetylenediurea(TA)-CO-succinyl chloride)(PTS))was proposed to be used as an organic additive in aqueous ZnSO_(4)electrolyte to achieve a highly reversible zinc/manganese oxide *** is found that the zinc symmetric battery based on the 2.0 wt.%PTS/ZnSO_(4)electrolyte showed a long cycle stability of more than 2400 h at 1.0 mA·cm^(-2),which is much longer than that including the blank ZnSO_(4)electrolyte(140 h).Furthermore,the capacity retention of the Zn||MnO_(2)full cells employing the 2.0 wt.%PTS/ZnSO_(4)electrolyte remained 85%after 100 cycles at 0.2 A·g^(1),which is much higher than 20%capacity retention of the cell containing the blank ZnSO_(4)electrolyte,and also greater than 59.6%capacity retention of the cell including the 10.0 wt.%TA/ZnSO_(4)*** using 2.0 wt.%PTS/ZnSO_(4)electrolytes,the capacity retention of the Zn||MnO_(2)full cells even reached 65%after 2000 cycles at a higher current density of 1.0 A·g^(1).It is further demonstrated that the PTS was firmly adsorbed on the zinc anode surface to form a protective layer.

关键词： aqueous zinc-ion battery hydrophilic branched polyester Zn anode protection Zn dendrite adsorption

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