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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

Mechanism and control of water seepage of vertical feeding borehole for solid materials in backflling coal mining

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International Journal of Mining Science and Technology 2013年第5期23卷 675-679页

作者： Zhou Yuejin Guo Hongzeng Cao Zhengzheng zhang jiangong State Key Laboratory of Geomechanics and Deep Underground Engineering China University of Mining & Technology School of Mines China University of Mining & Technology

To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding *** with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical *** results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic *** higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will *** practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.

关键词： Backflling coal mining Vertical feeding borehole Mechanism of water seepage Optimum moisture content

Statistical Analysis of Radio Interference of 1000 kV UHV AC Double-circuit Transmission Lines in Foul Weather

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CSEE Journal of Power and Energy Systems 2016年第2期2卷 47-55页

作者： Huichun Xie Xiang Cui Baoquan Wan jiangong zhang State Key Laboratory of Alternate Electrical Power System with Renewable Source(NCEPU) Beijing 102206China China Electric Power Research Institute Wuhan 430074China

Analyzing the impact of radio interference(RI)variation during foul weather conditions is an area that has received limited *** paper provides a statistical analysis of RI measurements obtained from a long-term observation station close to the world’s first commercially operating 1000 kV UHV AC double-circuit transmission line in *** six months of observations,the impact of RI was studied on the line during fog,drizzle,and light snow and *** was found that RI increases linearly with the natural logarithm of the precipitation *** Levenberg-Marquardt algorithm(LMA)is employed to fit the RI value with the precipitation *** reasonable distribution of RI in different foul weather is verified by one-sample K-S *** test is seen as beneficial for further RI prediction based on statistical weather mode.

关键词： 1000 kV UHV AC double-circuit transmission line foul weather precipitation intensity radio interference statistical analysis

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

Development in Researches on Reradiation Interference from UHV Power Lines

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高电压技术 2013年第10期39卷 2372-2382页

作者： TANG Bo ZHAO Zhibin zhang jiangong LIU Xingfa CHEN Bin College of Electronic Engineering & New Energy China Three Gorges University Yichang 443002 China College of Electricial and Electronic North China Electric Power University Baoding 071003 China China Electric Power Research Institute Wuhan 430074 China)

Reradiation interference(RRI) from ultra high voltage(UHV) power lines has become a hotspot for researches in electromagnetic(EM) interference between UHV power grids and adjacent radio *** mechanism of RRI,numerical simulations,methods of protecting distance calculation,and resonance characteristics of RRI are reviewed in this paper using results of works reported by IEEE and Chinese *** conclude in this review that RRI at short and medium wavelengths can be simulated using method of moment(MoM) and two commonly used models,the wire model and the surface model,which have different applicable *** indicate that the accurate simulation of RRI at higher frequencies using uniform geometrical theory of diffraction is still beyond our capability because it requires studies of the relative simulation *** also suggest that further researches of the mechanism of RRI and the prediction of resonance frequencies above 1.7 MHz are necessary for dealing with the interference between the existing power lines and radio stations because resonance frequencies proposed by IEEE are less than 1.7 MHz.

关键词：特高压输电线路辐射干扰数值模拟共振频率电力线路 IEEE 共振特性表面模型

Radio Interference Characteristic of Ultra-high Voltage AC Transmission Lines by Using Stochastic Modeling

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高电压技术 2013年第10期39卷 2438-2444页

作者： HE Wangling WAN Baoquan PEI Chunming zhang jiangong HE Junjia GUO Haozhou School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China China Electric Power Research Institute Wuhan 430074 China

For developing ultra-high voltage(UHV) AC power transmission systems,it is important to precisely estimate and to limit the radio interference(RI) level of power *** on the stochastic characteristics in amplitude and repetition rate of induced corona current,by using the probability theory and mathematical statistics,we establish a stochastic model for the wide-sense stationary random process of corona *** combining the stochastic model with model-propagation-analysis method,the RI levels under three-phase UHV AC transmission lines are *** results of the calculation based on stochastic model method and International Council on Large Electric Systems(CIGRE) excitation function are compared with that based on semi-empirical method and some other excitation *** stochastic model based on different excitation functions is also adopted to simulate the RI levels under finite test lines with two opened *** results indicate that with the same average maximum gradient on conductor surface and the same conductor type,the number of corona discharge per unit length is one of the main reasons that causes the difference between different excitation *** is also concluded that for a long test line,the effect of standing wave on RI field strength is negligible in the middle of the line,but obvious near both terminations: for a 10-km line,the maximum difference in RI field strength is 2.78 dB,between the peak value of the standing wave near the ends and the steady value near the middle of the line.

关键词：特高压输电线路交流输电线路无线电干扰随机建模干扰特性概率论与数理统计电力传输系统平稳随机过程

Fracture mechanics model of fully mechanized top coal caving of shallow coal seams and its application

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International Journal of Mining Science and Technology 2014年第3期24卷 349-352页

作者： zhang jiangong Miao Xiexing Huang Yanli Li Meng School of Mines China University of Mining and Technology Key Laboratory of Deep Coal Resource Mining Ministry of Education of China

Based on break characteristics of roofs in fully mechanized top-coal mining of thick shallow coal seams, a fracture mechanics model was built, and the criterion of crack propagation in the main roof was derived using the fracture mechanics theory. The relationships between the fracture length of the roof and the working resistance of the supports were discovered, and the correlations between the load on the overlying strata and the ratio of the crack's length to the thickness of the roof were obtained. Using a working face of Jindi Coal Mine, Xing county Shanxi province as an example, the relationships between the fracture length of the roof and the working resistance of the supports were analysed in detail. The results give a design basis in hydraulic top coal caving supports, which could provide useful references in the practical application. On-site experiment proves that the periodic weighting step interval of the caving face is 15–16 m, which is basically consistent with the theoretical analysis results, and indicates that the mechanized caving hydraulic support is capable of meeting the support requirements in the mining of a super-thick but shallowly buried coal seam.

关键词： Super-thick shallow coal seam Fully mechanized top-caving mining Main roof Fracture mechanics model0

基于方波电压注入的刮板机重载启动控制策略研究

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煤炭科学技术 2019年第2期47卷 136-142页

作者：张建公开滦(集团)有限责任公司河北唐山063000

针对煤矿刮板机传统启动方法启动速度慢、启动转矩控制不精确与启动耗能大等问题,研究了一种基于无滤波器载波信号分离的高频方波电压注入法的刮板机启动方法,通过引入永磁电动机转子位置与转速的观测器,能够实现启动转矩的精确控制,实... 详细信息

针对煤矿刮板机传统启动方法启动速度慢、启动转矩控制不精确与启动耗能大等问题,研究了一种基于无滤波器载波信号分离的高频方波电压注入法的刮板机启动方法,通过引入永磁电动机转子位置与转速的观测器,能够实现启动转矩的精确控制,实现快速与平稳启动;无滤波器载波信号分离策略可以避免传统方法信号分离过程中滤波器的使用,从而提高了系统的动态性能。仿真结果表明:基于高频电压注入的刮板机重载启动方法与传统的I/F启动方式相比,启动时间减少约52.3%,启动电流减小约75.0%,有效改善了刮板机启动性能。

关键词：刮板机重载启动永磁同步电动机高频方波电压注入

企业需求导向下全日制工程硕士学习成果评价实证研究

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国家教育行政学院学报 2022年第4期292卷 61-69页

作者：张建功华南理工大学广东广州510640

学习成果强调教育成效证据,以学生学习增值客观评价教育质量而备受关注。基于企业需求的视角,构建了全日制工程硕士学习成果评价体系,并对全国6大区域、 76所不同类型高校的3080名全日制工程硕士学习成果进行了实证研究。结果表明:全日... 详细信息

学习成果强调教育成效证据,以学生学习增值客观评价教育质量而备受关注。基于企业需求的视角,构建了全日制工程硕士学习成果评价体系,并对全国6大区域、 76所不同类型高校的3080名全日制工程硕士学习成果进行了实证研究。结果表明:全日制工程硕士学习成果总体处于中等水平,距离企业需求仍有一定差距;全日制工程硕士学习成果的显著性差异与区域、高校类型和年级有关,而与专业类别和性别无关。根据研究结果,从完善课程设置、夯实专业知识,落实专业实践、强化应用能力,打破学科壁垒、提升融合水平,推进课程思政、培养公民意识等方面提出了相应的对策。

关键词：工程硕士学习成果能力导向评价