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7th IEEE International Electrical and Energy Conference, CIEEC 2024

作者： Zhou, Yuanxiang Xu, Jingfan School of Electrical Engineering Xinjiang University Tsinghua University The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment Beijing100084 China School of Electrical Engineering Xinjiang University The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment Urumqi830047 China

ISBN: (纸本)9798350359558

This paper adopts a linear temperature change method to subject epoxy resin to thermal cycling within a temperature range of -40 °C to 70°C at different rates of temperature change (1 °C/min and 10 °C/min), exploring the effects of thermal cycling duration and rate of temperature change on the glass transition temperature and dielectric properties of the epoxy resin. The results indicate that with an increase in cycling duration, both the dielectric constant and dielectric loss of the epoxy resin first decrease and then increase. Moreover, under a temperature change rate of 10 °C/min, this trend shows a smaller decrease in the early stages of cycling and a more significant increase in the later stages. Analysis reveals that thermal cycling promotes dynamic adjustment of internal chain segments in the epoxy resin, resulting in a denser structure and enhanced binding capacity to polar groups, which increases the glass transition temperature and improves the dielectric properties of the epoxy resin in the early stages. However, as the number of cycles increases, molecular chains break under the long-term effects of thermal expansion and contraction, gradually deteriorating the dielectric properties. Furthermore, a faster rate of temperature change prevents the internal chain segments of the epoxy resin from adjusting sufficiently, and the increased stress impact makes the epoxy resin more prone to degradation. © 2024 IEEE.

关键词： Thermal cycling

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Effect of Low Frequency Electrical Aging on Conductive Current Characteristics of Cross-Linked Polyethylene Films 18th

Effect of Low Frequency Electrical Aging on Conductive Curre...

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18th Annual Conference of China Electrotechnical Society, ACCES 2023

作者： Huang, Jiyu Zhou, Yuanxiang Chen, Jianning Jiang, Guimin Zhu, Xiaoqian Wind Solar Storage Division of State Key Lab of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi830047 China State Key Laboratory of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9789819714469

With the construction of offshore wind power projects, cross-linked polyethylene (XLPE) submarine cables are gradually applied to low frequency power transmission. However, the electrical aging characteristics and mechanisms of XLPE at low frequency remain unclear. In order to study the effect of low frequency electrical aging on the electrical conductivity current characteristics of XLPE and its difference from power frequency electrical aging, accelerated electrical aging experiment of XLPE films are conducted under applied AC voltage of 20 Hz and 50 Hz. The electrical conductivity current characteristics of XLPE films are measured at different electric field strengths after 3, 6 and 9 days of electrical aging. The results show that the conductive currents of XLPE increased with the growth of accelerated electrical aging time at both low frequency and power frequency. The conductivity current increases from 6 pA to 147 pA after 9 d of aging at power frequency, and from 6 pA to 307 pA at low frequency. The conductive current increases more at low frequency than at power frequency, the 20 Hz conductivity current is 80%, 63% and 52% higher than the 50 Hz conductivity current at 3 d, 6 d and 9 d aging, respectively. In addition, the electric field remains above the charge injection threshold for a longer period of time in a single cycle at low frequency, so the low frequency voltage enhances the charge carrier mobility and space charge trapping probability in the insulating medium, generating more thermionic and causing more polymer chain breaks, resulting in higher conductivity currents under low frequency aging compared with power frequency. © Beijing Paike Culture Commu. Co., Ltd. 2024.

关键词： Electric power transmission

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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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Multi-physics Based Temperature Distribution Simulation of HVAC Submarine Cable at Various Velocity 4th

Multi-physics Based Temperature Distribution Simulation of H...

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4th International Symposium on Insulation and Discharge Computation for power equipment, IDCOMPU 2023

作者： Zhang, Zhen Zhou, Yuanxiang Chen, Jianning Li, Yuhang Dai, Yasong The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi830047 China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9789819974009

The temperature distribution of submarine cables is an important parameter reflecting its operation status. The acquisition of temperature distribution trends for submarine cables under varying seawater flow rates holds important engineering significance. In this paper, the geometric model is constructed using a 220 kV three-core AC armored submarine cable laid on the seabed. The simulation model of AC three-core submarine cable temperature field is proposed based on the coupling of electro-thermal-flow multi-physics field. Finally, the study investigates how the steady-state temperature distribution of submarine cables varies with different seawater flow velocities. The results show that the temperature is radially distributed at the seawater velocity of 0m/s, and the temperatures of different phase conductors are different by the relative position, which are 89.9 °C, 89.6 °C and 89.08 °C, respectively. As the seawater flow velocity increases, the heat taken away from the cable surface by convection increases. When the seawater flow velocity is 1 × 10−6m/s, 0.0001 m/s, 0.001 m/s, 0.001 m/s and 0.001 m/s, the maximum conductor temperatures are 69.5 °C, 44.6 °C, 38.5 °C, 33.6 °C and 32.7 °C, and the ampacity is 871.7 A, 1216 A, 1382.8 A, 1590.7 A and 1640.9 A, respectively. The simulation results can provide reference for submarine cable transmission engineering design. © 2024, Beijing Paike Culture Commu. Co., Ltd.

关键词： Temperature distribution

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Simulation of Arc Erosion on the Main Contact of On-Load Tap Changer 4th

Simulation of Arc Erosion on the Main Contact of On-Load Tap...

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4th International Symposium on Insulation and Discharge Computation for power equipment, IDCOMPU 2023

作者： Zhou, Yuanxiang Dai, Yasong Chen, Jianning Li, Yuhang Hou, Xuzhao Zhang, Zhen State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi830047 China

ISBN: (纸本)9789819974047

Long-term operation and switching of transformer on-load tap-changers can cause degradation and deterioration of the main contact material, even leading to contact arcing damage in severe cases. However, the arcing mechanism of the main contact during the switching has not been clarified yet. A magneto-hydrodynamic simulation method of main contact arcing has been proposed. The geometry of the main contact in transformer oil is simplified, and the simulation model of the arc temperature field of the main contact in transformer oil coupled with electric, magnetic, thermal and fluid fields is proposed. The dynamic evolution of the arc temperature has been investigated at peak currents of 2100 A, 1500 A, 600 A and 300 A, respectively. The results show that with the increase of the spacing between contacts, the temperature at arc core rises rapidly and then decreases slowly, and the temperature can reach 50177 K at 2100A. Due to the electron bombardment at the anode surface, the temperature at anode surface is higher than that at cathode surface under different chopped currents. The highest temperatures at anode and cathode surface can reach 4142.5 K and 4081.7 K respectively. © Beijing Paike Culture Commu. Co., Ltd 2024.

关键词： Deterioration

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Electrical resistivity-temperature characteristics enhancement of insulating cross-linked polyethylene composites by incorporating positive temperature coefficient particles with different Curie temperatures

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High Voltage 2023年第1期8卷 1-11页

作者： Guimin Jiang Yuanxiang Zhou Chenyuan Teng Yunxiao Zhang Xin Huang Lei Xue Luming Zhou The Wind Solar Storage Division of State Key Laboratory of Control and Simulation of Power System and Generation Equipment Xinjiang UniversityUrumqiChina State Key Laboratory of Power System and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijingChina College of Information Engineering Zhejiang University of TechnologyHangzhouChina School of Electronics and Computer Science University of SouthamptonSouthamptonUK

Incorporating positive temperature coefficient(PTC)ceramic particles into polymers provides a prospective alternative solution for suppressing severe electric field distortions caused by negative temperature coefficient(NTC)of electrical resistivity within polymer insulation in high voltage direct current *** effect of the Curie temperature of PTC particles on the inhibition of the NTC effect of cross-linked polyethylene(XLPE)is investigated in this *** temperature coefficient particles with varied Curie temperatures are surface-modified and melt blending with *** modified particles are dispersed on averagely in the *** electrical resistivity,space charge behaviour,and direct current(DC)electrical breakdown strength of the samples are investigated at different temperatures,exploring the effect of the Curie temperature of PTC particles on suppressing the NTC effect of *** is demonstrated that the reduction in Curie temperature can further suppress the NTC effect of XLPE,enhance the DC strength at elevated temperatures,and inhibit the internal space charge *** reduction in the Curie temperatures means that the initiation of the PTC effect advances,exhibiting a higher potential barrier and inhibiting the NTC effect more *** work may give a reference for improving the temperature stability of DC properties for XLPE cable insulation.

关键词： coefficient resistivity insulation

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Improvement of the Electrical Properties of Silicone Rubber Doped with Nano-zirconia Grafted by Voltage Stabilizer 4

Improvement of the Electrical Properties of Silicone Rubber ...

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4th IEEE International Conference on Electrical Materials and power equipment, ICEMPE 2023

作者： Zhu, Xiaoqian Zhou, Yuanxiang Zhang, Yunxiao Chen, Ming Liu, Xuanhao Tsinghua University State Key Lab of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Beijing China Fuzhou University College of Electrical Engineering and Automation Fuzhou China Xiamen Power Supply Company State Grid Fujian Electric Power Company Xiamen China Xinjiang University The Wind Solar Storage Division State Key Laboratory of Control and Simulation of Power System and Generation Equipment School of Electrical Engineering Urumqi China

ISBN: (纸本)9798350334678

Enhancing the electrical performance of silicone rubber (SiR) for cable accessories is noteworthy as they are almost the weakest parts of the cable system. Two types of voltage stabilizers were grafted onto the surface of nano-zirconia (ZrO2) particles, and the grafted nanoparticles were added to the SiR. Measurements such as breakdown strength, and conductivity were carried out to evaluate the electrical performance of SiR nanocomposites. The electrical performance measurement results indicated that the breakdown strength of the nanocomposite SiR improved while the conductance current was reduced. The trap distribution showed that the improvement of the electrical performance of the nanocomposite SiR is mainly due to the decrease of the shallow trap density or the increase of the deep trap density. © 2023 IEEE.

关键词： Nanoparticles

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Effect of Thermal Cycling on the Dielectric Properties of Epoxy Resin

Effect of Thermal Cycling on the Dielectric Properties of Ep...

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China International Electrical and Energy Conference (CIEEC)

作者： Yuanxiang Zhou Jingfan Xu The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Tsinghua University Beijing China The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi China

ISBN: (数字)9798350359558

ISBN: (纸本)9798350359565

关键词： Degradation Temperature distribution Thermal expansion Epoxy resins Dielectric losses Glass Market research

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Space Charge Transport of Al2O3/Silicone Rubber Composites under Thermal Aging

Space Charge Transport of Al2O3/Silicone Rubber Composites u...

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2022 IEEE International Conference on High Voltage Engineering and Applications, ICHVE 2022

作者： Zhang, Yunxiao Yan, Chenning Wu, Kai Zhou, Yuanxiang Zhang, Tianfeng College of Electrical Engineering and Automation Fuzhou University Fujian Fuzhou China Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing China School of Electrical Engineering Xinjiang University The Wind Solar Storage Division State Key Laboratory of Power System and Generation Equipment Urumqi China Electric Power Research Institute Anhui Electric Power Company of State Grid Hefei China

ISBN: (纸本)9781665407502

Silicone rubber (SIR) has been widely used in the insulation of cable accessories due to its excellent performance. In this paper, pure SIR and nano Al2O3/SIR composites are thermally aged for 0-80 days at 200°C. The effects of long-term thermal aging on the space charge transport are analyzed. The results show that with the increase of thermal aging time, the accumulation of heteropolar charge of pure SIR and nano Al2O3/SIR composites gradually decreases and changes to the accumulation of homopolar charge. Compared with pure SIR, the space charge accumulation of Al2O3/SIR composites decreases significantly and changes little with the increase of thermal aging time. It is believed that when doped nano Al2O3 in SIR, the increase of carrier mobility and the introduction of metal oxides reacting with fallen free radicals to form stable compounds both lead to less space charge accumulation of Al2O3/SIR composites. © 2022 IEEE.

关键词： Aluminum oxide

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Improvement of the Electrical Properties of Silicone Rubber Doped with Nano-zirconia Grafted by Voltage Stabilizer

Improvement of the Electrical Properties of Silicone Rubber ...

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International Conference on Electrical Materials and power equipment (ICEMPE)

作者： Xiaoqian Zhu Yuanxiang Zhou Yunxiao Zhang Ming Chen Xuanhao Liu State Key Lab of Control and Simulation of Power System and Generation Equipment & Department of Electrical Engineering Tsinghua University Beijing China College of Electrical Engineering and Automation Fuzhou University Fuzhou China Xiamen Power Supply Company State Grid Fujian Electric Power Company Xiamen China The Wind Solar Storage Division of State Key Laboratory of Control and Simulation of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi China

Enhancing the electrical performance of silicone rubber (SiR) for cable accessories is noteworthy as they are almost the weakest parts of the cable system. Two types of voltage stabilizers were grafted onto the surface of nano-zirconia (ZrO 2 ) particles, and the grafted nanoparticles were added to the SiR. Measurements such as breakdown strength, and conductivity were carried out to evaluate the electrical performance of SiR nanocomposites. The electrical performance measurement results indicated that the breakdown strength of the nanocomposite SiR improved while the conductance current was reduced. The trap distribution showed that the improvement of the electrical performance of the nanocomposite SiR is mainly due to the decrease of the shallow trap density or the increase of the deep trap density.

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