Coupled-plate structures are widely used in the practical engineering such as aeronautical,civil and naval engineering etc.Limited works can be found on the vibration of the coupled-plate structure due to the increase...Coupled-plate structures are widely used in the practical engineering such as aeronautical,civil and naval engineering etc.Limited works can be found on the vibration of the coupled-plate structure due to the increased mathematical complexity compared with the single plate structure.In order to study analytically the vibration characteristics and power transmission of the coupled-plate structure,an analytical model consisting of three coupled plates elastically restrained along boundary edges and elastically coupled with arbitrary angle is considered,in which four groups of springs are distributed consistently along each edge of the model to simulate the transverse shearing forces,bending moments,in-plane longitudinal forces and in-plane shearing forces separately.With elastic coupling condition and general boundary condition of both flexural and in-plane vibrations taken into account by setting the stiffness of corresponding springs,the double Fourier series solution to the dynamic response of the structure was obtained by employing the Rayleigh-Ritz method.In order to validate the model,the natural frequency and velocity response of the model are firstly checked against results published in literatures and the ANSYS data,and good agreement was observed.Then,numerical simulation of the effects of several relevant parameters on the vibration characteristics and power transmission of the coupled structure were performed,including boundary conditions,coupling conditions,coupling angle,and location of the external forces.Vibration and energy transmission behaviors were analyzed numerically.The results show that the power transmission can be significantly influenced by the boundary restraints and the location of excitation.When the excitation is located at the central symmetry point of the model,the energy flow shows a symmetrical distribution.Once the location deviates from the central symmetry point,the power circumfluence occurs and the vortex energy field is formed at high frequency.展开更多
Power is the nucleus of social and political life. Effective restraint on and supervision over the operation of power is the fundamental way of preventing corruption of power, which at the same time constitutes an imp...Power is the nucleus of social and political life. Effective restraint on and supervision over the operation of power is the fundamental way of preventing corruption of power, which at the same time constitutes an important indication to democracy and its development in a given country. Looking forward to attaining the strategic goal of building a society of relative prosperity in all aspects, the Sixteenth National Congress of the Communist Party of China called for ＂strengthening the restraint of and supervision over power to ensure that power given by the people is truly used to promote the interests of the people.＂ The call specifies, in explicit language, the target of institutionalizing socialist democracy characterized by standardized operations in accordance with legal procedures.展开更多
介绍了牵引供电系统的结构特点,并针对铁道牵引系统负荷分时性、空载率高的特点,设计了机械投切电容器MSC(mechanical switch capacitor)及晶闸管控制电抗器TCR(thyristor control reactor)型的无功补偿及滤波装置,并在PSCAD软件中建模...介绍了牵引供电系统的结构特点,并针对铁道牵引系统负荷分时性、空载率高的特点,设计了机械投切电容器MSC(mechanical switch capacitor)及晶闸管控制电抗器TCR(thyristor control reactor)型的无功补偿及滤波装置,并在PSCAD软件中建模、仿真,分析了在不同牵引负荷情况下MSC-TCR型静止无功补偿装置分组投切无功补偿效果和谐波滤除作用,为保证牵引供电系统的电能质量提供参考.展开更多
研究了具备低电压穿越(Low Voltage Ride-Through,LVRT)能力的光伏并网发电系统,送出线部分发生三相短路故障时,LVRT控制过程中发出的无功电流对传统比率制动式和新型标积制动式差动保护灵敏度的影响。理论分析表明故障期间无功补偿会...研究了具备低电压穿越(Low Voltage Ride-Through,LVRT)能力的光伏并网发电系统,送出线部分发生三相短路故障时,LVRT控制过程中发出的无功电流对传统比率制动式和新型标积制动式差动保护灵敏度的影响。理论分析表明故障期间无功补偿会导致两种差动保护的灵敏度下降,并通过Simulink搭建光伏并网发电系统仿真模型验证了这一结论。在此基础上,进一步对比得出发生金属性短路故障时,标积制动式差动保护的灵敏度受无功补偿影响较小,作为光伏电站送出线部分的保护效果更佳。最后通过差动特性曲线的整定方式,对如何提升差动保护灵敏度的问题提出改进建议。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 10802024)Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200802171009)Innovative Talents Fund of Harbin of China(Grant No.2009RFQXG211)
文摘Coupled-plate structures are widely used in the practical engineering such as aeronautical,civil and naval engineering etc.Limited works can be found on the vibration of the coupled-plate structure due to the increased mathematical complexity compared with the single plate structure.In order to study analytically the vibration characteristics and power transmission of the coupled-plate structure,an analytical model consisting of three coupled plates elastically restrained along boundary edges and elastically coupled with arbitrary angle is considered,in which four groups of springs are distributed consistently along each edge of the model to simulate the transverse shearing forces,bending moments,in-plane longitudinal forces and in-plane shearing forces separately.With elastic coupling condition and general boundary condition of both flexural and in-plane vibrations taken into account by setting the stiffness of corresponding springs,the double Fourier series solution to the dynamic response of the structure was obtained by employing the Rayleigh-Ritz method.In order to validate the model,the natural frequency and velocity response of the model are firstly checked against results published in literatures and the ANSYS data,and good agreement was observed.Then,numerical simulation of the effects of several relevant parameters on the vibration characteristics and power transmission of the coupled structure were performed,including boundary conditions,coupling conditions,coupling angle,and location of the external forces.Vibration and energy transmission behaviors were analyzed numerically.The results show that the power transmission can be significantly influenced by the boundary restraints and the location of excitation.When the excitation is located at the central symmetry point of the model,the energy flow shows a symmetrical distribution.Once the location deviates from the central symmetry point,the power circumfluence occurs and the vortex energy field is formed at high frequency.
文摘Power is the nucleus of social and political life. Effective restraint on and supervision over the operation of power is the fundamental way of preventing corruption of power, which at the same time constitutes an important indication to democracy and its development in a given country. Looking forward to attaining the strategic goal of building a society of relative prosperity in all aspects, the Sixteenth National Congress of the Communist Party of China called for ＂strengthening the restraint of and supervision over power to ensure that power given by the people is truly used to promote the interests of the people.＂ The call specifies, in explicit language, the target of institutionalizing socialist democracy characterized by standardized operations in accordance with legal procedures.
文摘介绍了牵引供电系统的结构特点,并针对铁道牵引系统负荷分时性、空载率高的特点,设计了机械投切电容器MSC(mechanical switch capacitor)及晶闸管控制电抗器TCR(thyristor control reactor)型的无功补偿及滤波装置,并在PSCAD软件中建模、仿真,分析了在不同牵引负荷情况下MSC-TCR型静止无功补偿装置分组投切无功补偿效果和谐波滤除作用,为保证牵引供电系统的电能质量提供参考.
文摘研究了具备低电压穿越(Low Voltage Ride-Through,LVRT)能力的光伏并网发电系统,送出线部分发生三相短路故障时,LVRT控制过程中发出的无功电流对传统比率制动式和新型标积制动式差动保护灵敏度的影响。理论分析表明故障期间无功补偿会导致两种差动保护的灵敏度下降,并通过Simulink搭建光伏并网发电系统仿真模型验证了这一结论。在此基础上,进一步对比得出发生金属性短路故障时,标积制动式差动保护的灵敏度受无功补偿影响较小,作为光伏电站送出线部分的保护效果更佳。最后通过差动特性曲线的整定方式,对如何提升差动保护灵敏度的问题提出改进建议。
