Anti-seismic Analysis And Virtual Prototype Simulation On Transformer With Nonlinear Isolation Device

As the transformer tonnage weighing hundreds of tons,even UHV transformer weighing thousands of tons,and the newly heavy-duty HUV transformers are still being developed and promoted,and seismic wave excitation frequency is low whose direction of randomness is very large,the traditional linear isolator has been gradually unable to meet the actual needs.Linear isolator has a good vibration isolation effect for highfrequency signal,although with the help of active isolation technology linear isolator can meet the requirements of low-frequency vibration isolation,but its control system and environmental stability requirements are higher,and for the transformer such "sillyrough-heavy" electrical equipment,the cost is higher,the maintenance and operation are more complicated.Therefore,combined with the existing transformer seismic engineering practice,to carry out low frequency passive isolation research and design low frequency isolation with the nonlinear isolator on the transformer actually has important practical significance.The SD oscillator theory was proposed by Prof.Cao Qingjie in 2006,based on which a new quasi-zero stiffness isolation model is proposed and a geometrical non-linear twostage quasi-zero stiffness isolation device is designed.Combined with numerical calculation and prototype simulation technology,the anti-seismic effect of the device is proved.The main contents of this paper are as follows:Firstly,based on the theory of SD oscillator,a geometric nonlinear quasi-zero stiffness model is established.The model consists of a segregated body,two oblique springs and horizontal linear trajectories.The nonlinear force-displacement and stiffness characteristics of the model are studied.The amplitude-frequency curve is analyzed under the excitation of the simple harmonic acceleration wave.The acceleration transfer rate and the displacement transfer rate are deduced,and the different sensitive parameters are discussed.Secondly,the geometric nonlinear quasi-zero stiffness theoretical model under the action of seismic wave is calculated by the Runge-Kutta method.The influence of different system parameters on the acceleration transfer rate is obtained.Then,the optimal physical parameters of the isolator for the transformer are calculated with the acceleration transfer rate as the target.Finally,according to the numerical optimal parameters calculated above,the geometric nonlinear two-stage quasi-zero stiffness isolation device is designed.For the structure,the virtual prototyping simulation of the multi rigid body dynamics software ADAMS is carried out.The three typical horizontal directions of the seismic wave excitation were simulated,namely X-axis,Y-axis and the direction of 45 degrees in the axial direction.The response indexes of these three directions of seismic wave excitation are obtained,and the accuracy of the above theoretical derivation and numerical calculation are verified.At the same time,in order to compare with the linear isolation system,in the end of this paper,the equivalent linear two-stage isolation device also carried out a prototype simulation analysis.It is concluded that the geometric nonlinear two-stage quasi-zero stiffness isolation device has lower isolation frequency than the linear two-stage isolation device,the resonance peak suppressing effect is better,and the seismic wave can be more effectively isolated,thus ensuring the transformer is safe,reliable and effective to run.