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Vibration Characteristics Analysis and Structure Optimization of Catenary Portal Structure on Four-Wire Bridge

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Structural Durability & Health Monitoring 2022年第4期16卷 361-382页

作者： sihua wang Xujie Li School of Automation&Electrical Engineering Lanzhou Jiaotong UniversityLanzhou730070China Rail Transit Electrical Automation Engineering Laboratory of Gansu Province(Lanzhou Jiaotong University) Lanzhou730070China

The portal structure is the support equipment in the catenary,which bears the load of contact suspension and support equipment.In practical work,with the change of external forces,the support equipment bears complex and changeable loads,so it has higher requirements for its reliability and safety.In order to study the dynamic characteristics of catenary portal structure on continuous beam of four-way bridge,taking the catenary portal structure on Dshaping four-way bridge as the research object,the portal structure simulation model of bridgenetwork integration was established in Midas Civil.The maximum point of deformation and stress was determined by finite element analysis of catenary hard span equipment,and the frequency and mode of natural vibration of hard span were obtained by modal analysis.Secondly,through the field dynamic stress acquisition test,combined with the results of finite element analysis,the fault location is determined,and the vibration characteristics are analyzed.Finally,based on the results of modal analysis and vibration analysis,the method that the vibration of portal structure beam is affected by structural stiffness and vibration frequency amplitude is proposed.The torsional vibration of the portal structure beam was suppressed by increasing the stiffness of the beam and reducing the vibration conduction between the trolley and the beam,and the hard cross beam was optimized by strengthening the hanging column and the connecting beam and adding diagonal support between the pillar and the portal structure beam.By comparing the values of shear,bending moment,displacement and dynamic stress on the hard span before and after optimization,the amplitude peak after structural optimization is reduced by about 25%,and the application of oblique support and reinforcement of the beam can significantly improve the portal structure vibration.

关键词： Catenary portal structure vibration analysis modal analysis structural optimization

Research on Flashover Voltage Prediction of Catenary Insulator Based on CaSO_(4) Pollution with Different Mass Fraction

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Energy Engineering 2022年第1期119卷 219-236页

作者： sihua wang Junjun wang Lijun Zhou Long Chen Lei Zhao College of Automation&Electrical Engineering Lanzhou Jiaotong UniversityLanzhou730070China Rail Transit Electrical Automation Engineering Laboratory of Gansu Province Lanzhou Jiaotong UniversityLanzhou730070China

Pollution flashover accidents occur frequently in railway OCS in saline-alkali areas.To accurately predict the pollution flashover voltage of insulators,a pollution flashover warning should be made in advance.According to the operating environment of insulators along the Qinghai-Tibet railway,the pollution flashover experiments were designed for the cantilever composite insulator FQBG-25/12.Through the experiments,the flashover voltage under the influence of soluble contaminant density(SCD)of different pollution components,non-soluble deposit density(NSDD),temperature(T),and atmospheric pressure(P)was obtained.On this basis,the GA-BP neural network prediction model was established.P,SCD,NSDD,CaSO_(4) mass fraction(w(CaSO_(4))),and T were taken as input parameters,50%flashover voltage(U_(50%))of the insulator was taken as output parameters.The results showed that the prediction deviation was less than 10%,which meets the basic engineering requirements.The results could not only provide early warning for the anti-pollution flashover work of the railway power supply department,but also be used as an auxiliary contrast to verify the accuracy of the results of the experiments,and provide a theoretical basis for the classification of pollution levels in different regions.

关键词： Overhead contact system w(CaSO_(4)) insulator pollution flashover test genetic algorithm-back propagation(GA-BP)neural network flashover voltage prediction

Fault Diagnosis of Wind Turbine Generator with Stacked Noise Reduction Autoencoder Based on Group Normalization

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Energy Engineering 2022年第6期119卷 2431-2445页

作者： sihua wang Wenhui Zhang Gaofei Zheng Xujie Li Yougeng Zhao School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou730070China Rail Transit Electrical Automation Engineering Laboratory of Gansu Province(Lanzhou Jiaotong University) Lanzhou730070China

In order to improve the condition monitoring and fault diagnosis of wind turbines,a stacked noise reduction autoencoding network based on group normalization is proposed in this paper.The network is based on SCADA data of wind turbine operation,firstly,the group normalization(GN)algorithm is added to solve the problems of stack noise reduction autoencoding network training and slow convergence speed,and the RMSProp algorithm is used to update the weight and the bias of the autoenccoder,which further optimizes the problem that the loss function swings too much during the update process.Finally,in the last layer of the network,the softmax activation function is used to classify the results,and the output of the network is transformed into a probability distribution.The selected wind turbine SCADA data was substituted into the pre-improved and improved stacked denoising autoencoding(SDA)networks for comparative training and verification.The results show that the stacked denoising autoencoding network based on group normalization is more accurate and effective for wind turbine condition monitoring and fault diagnosis,and also provides a reference for wind turbine fault identification.

关键词： Wind farm wind turbine group normalization stack noise reduction autoencoding fault diagnosis

Effect of Salty Fog on Flashover Characteristics of OCS Composite Insulators

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Chinese Journal of Electrical Engineering 2019年第3期5卷 59-66页

作者： sihua wang Youlong Wu College of Automation&Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070China Rail Transit Electrical Automation Engineering Laboratory of Gansu Province Lanzhou Jiaotong UniversityLanzhou 730070China

To study the flashover characteristics of the fog water in saline-alkali areas for high-speed railway OSC insulators,the spatial distributions of both the potential and electric field of soiled insulators in the presence of salty fog are analyzed using COMSOL Multiphysics,a multi-physics coupling software.Furthermore,to analyze the effect of the contamination of insulators due to salty fog water,a saline solution is used for staining an insulator sample by using the solid coating method.In an artificial climate chamber,the salty fog environment is simulated,and the flashover voltage for different salty fog water conductivities and surface staining are obtained.The salt-density correction coefficient K is also proposed.It provides a strong basis for the selection of railway insulators in saline-alkali areas.The results show that the salty fog water changes the original surface equivalent salt density,ρESDD,by wetting the existing fouling layer on the surface of the insulator,so that the original surface contamination layer becomes equivalent to KρESDD;the smaller is the value ofρESDD of the insulator surface,the larger is the value of K;the surface of the same insulator is dirty,and as the concentration of salty fog-water increases,K also increases.

关键词： Salty fog composite insulators flashover characteristics COMSOL multiphysics additional salt density

Fast Protection Strategy for DC Transmission Lines of MMC-based MT-HVDC Grid

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Chinese Journal of Electrical Engineering 2021年第2期7卷 83-92页

作者： sihua wang Lijun Zhou Tian wang Tianyu Chen Yu wang College of Automation&Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070China Rail Transit Electrical Automation Engineering Laboratory of Gansu Province Lanzhou Jiaotong UniversityLanzhou 730070China

Multi-terminal high voltage DC(MT-HVDC)grid has broad application prospects in connecting different energy sources,asynchronous interconnection of power grids,remote load power supply,and other fields.At present,the key technologies that affect the development of MT-HVDC transmission system include swift fault identification and location in the DC line and its rapid isolation.Traditional fault monitoring relies on line communication,which cannot guarantee the rapidity and reliability of protection;moreover,it may even cause device damage.A fault identification scheme based on a single-terminal transient is presented in this paper.This scheme calculates the line inductance by using the rise rate of fault current at the initial stage of the fault,and determines the occurrence of the fault by comparing the observed line inductance with the set value,which lays a foundation for calculating the location of the fault point using distance protection.A simulation model on the PSCAD/EMTDC platform is built;the simulation example verifies that the proposed scheme can identify faults under dissimilar conditions while maintaining a low error level on the premise of no communication lines so as to meet the protection requirements of the MT-HVDC grid.

关键词： Multi-terminal high voltage DC(MT-HVDC)grid modular multilevel converter(MMC) DC circuit breaker(DCCB) bipolar short-circuit fault identification

大风区段开孔式挡风墙对正馈线气动特性的影响

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哈尔滨工业大学学报 2024年第3期56卷 143-153页

作者：张友鹏冯强赵珊鹏王思华兰州交通大学自动化与电气工程学院兰州730070 甘肃省轨道交通电气自动化工程实验室(兰州交通大学) 兰州730070

兰新高速铁路常年遭受风灾,挡风墙的修建虽有效防止了列车倾覆,但加剧了接触网正馈线的舞动。针对大风区段既有挡风墙“防车不防网”的不足,通过设计一种开孔式挡风墙,基于流体力学理论建立计算域模型,对挡风墙的防风效果进行评估,并仿... 详细信息

兰新高速铁路常年遭受风灾,挡风墙的修建虽有效防止了列车倾覆,但加剧了接触网正馈线的舞动。针对大风区段既有挡风墙“防车不防网”的不足,通过设计一种开孔式挡风墙,基于流体力学理论建立计算域模型,对挡风墙的防风效果进行评估,并仿真分析挡风墙孔隙率及开孔角度对于正馈线气动特性响应的规律。结果表明:挡风墙设置一定孔隙率后,会冲击挡风墙后形成的旋涡流场,使流场趋于平稳;随着孔隙率的增大挡风墙尾流接触网正馈线位置处气流增速区范围大幅减小,且正馈线气动力系数呈明显降低趋势;当挡风墙孔隙率为0.3时,挡风墙背风侧风速残余系数为0.46~0.69,此时正馈线升、阻力系数下降率分别超过41.56%和24.59%;在孔隙率为0.3,且挡风墙设置150°开孔角度时,正馈线气动力系数相较其他角度降幅明显,从而对于正馈线的舞动可以起到进一步的抑制作用。研究成果可为兰新高铁大风区段接触网正馈线舞动防治及挡风墙优化提供一定的理论参考。

关键词：兰新高铁挡风墙防风效果正馈线气动特性

Upper-Tropospheric Environment–Tropical Cyclone Interactions over the Western North Pacific:A Statistical Study

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Advances in Atmospheric Sciences 2016年第5期33卷 614-631页

作者： Yu-Kun QIAN Chang-Xia LIANG Zhuojian YUAN Shiqiu PENG Junjie WU sihua wang Center for Monsoon and Environmental Research/Department of Atmospheric Science Sun Yat-sen UniversityGuangzhou 510275 State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301 South China Sea Marine Prediction Center South Oceanic AdministrationGuangzhou 510300 Civil Aviation Flight University of China Guanghan 618307 Luogang District Meteorological Bureau Guangzhou 510530

Based on 25-year（1987–2011） tropical cyclone（TC） best track data, a statistical study was carried out to investigate the basic features of upper-tropospheric TC–environment interactions over the western North Pacific. Interaction was defined as the absolute value of eddy momentum flux convergence（EFC） exceeding 10 m s^（-1）d^（-1）. Based on this definition, it was found that 18% of all six-hourly TC samples experienced interaction. Extreme interaction cases showed that EFC can reach^120 m s^（-1）d^（-1） during the extratropical-cyclone（EC） stage, an order of magnitude larger than reported in previous studies.Composite analysis showed that positive interactions are characterized by a double-jet flow pattern, rather than the traditional trough pattern, because it is the jets that bring in large EFC from the upper-level environment to the TC center. The role of the outflow jet is also enhanced by relatively low inertial stability, as compared to the inflow jet. Among several environmental factors, it was found that extremely large EFC is usually accompanied by high inertial stability, low SST and strong vertical wind shear（VWS）. Thus, the positive effect of EFC is cancelled by their negative effects. Only those samples during the EC stage, whose intensities were less dependent on VWS and the underlying SST, could survive in extremely large EFC environments, or even re-intensify. For classical TCs（not in the EC stage）, it was found that environments with a moderate EFC value generally below ~25 m s^（-1）d^（-1） are more favorable for a TC＇s intensification than those with extremely large EFC.

关键词： Tropical cyclone–trough interaction upper troposphere eddy momentum flux convergence

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压力管道斜井开挖施工工艺的综合效益研究

陕西水利 2024年第2期 151-152,159页

作者：张扬王思桦中国电建集团北京勘测设计研究院有限公司北京100024

针对某抽水蓄能电站压力管道斜井开挖断面直径大、深度大、地质条件较为复杂等特点,提出爬罐、反井钻机2种方案开挖斜井。在对2种方案的施工工艺进行对比分析之后,测算出爬罐、反井钻机斜井施工的生产成本,并从经济、环保、安全效益3个... 详细信息

针对某抽水蓄能电站压力管道斜井开挖断面直径大、深度大、地质条件较为复杂等特点,提出爬罐、反井钻机2种方案开挖斜井。在对2种方案的施工工艺进行对比分析之后,测算出爬罐、反井钻机斜井施工的生产成本,并从经济、环保、安全效益3个方面对2种施工方案的综合效益进行分析。分析结果显示:爬罐在经济效益方面具有一定优势,但反井钻机在环保效益与安全效益方面的优势显著,在水电工程建设领域具有广泛应用前景与推广价值。

关键词：爬罐反井钻机斜井施工综合效益

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大风区接触网线路参数对附加导线舞动的影响

哈尔滨工业大学学报 2024年第5期56卷 74-83页

作者：赵珊鹏陈智涛张友鹏王思华葛威张鹏飞兰州交通大学自动化与电气工程学院兰州730070 甘肃省轨道交通电气自动化工程实验室兰州730070

针对大风环境下兰新高速铁路接触网附加导线发生剧烈舞动以及线间放电的现象,依据接触网附加导线结构特点,建立了附加导线有限元计算模型,并对附加导线进行找形计算。采用谐波叠加法模拟接触网附加导线处的随机风场,并对导线模型施加风... 详细信息

针对大风环境下兰新高速铁路接触网附加导线发生剧烈舞动以及线间放电的现象,依据接触网附加导线结构特点,建立了附加导线有限元计算模型,并对附加导线进行找形计算。采用谐波叠加法模拟接触网附加导线处的随机风场,并对导线模型施加风荷载,利用无条件稳定Newmark法以及荷载增量法,分析接触网线路参数对附加导线舞动及线间距离的影响规律,并给出相应的舞动防治措施。结果表明:40 m及更小档距对导线在低风速及高风速下的舞动均有明显的抑制效果;将附加导线运行张力提高至6.5 kN,导线阻尼比提高至1.5%及以上能有效降低两条导线的舞动剧烈程度;接触网附加导线的档距过大,运行张力及阻尼比过小,将导致导线舞动时悬挂点张力过大,易引起导线掉线、断线等事故;随附加导线档距减小、运行张力及阻尼比增大,线间最小距离呈递增趋势;不同线路参数下(档距、运行张力及阻尼比)附加导线舞动时线间最小距离均随风速增大出现减小趋势。本研究可为兰新高铁大风区段接触网附加导线舞动及线间放电的防治提供有效的理论依据。

关键词：舞动特性线间最小距离附加导线接触网兰新高铁