Random Vibration Analysis Of Large Transformer During Transportation

Large transformers are the key to the construction of national smart grid.To ensure that they are not damaged in the process of transportation is the premise of normal use of large transformers.The traditional large transformer transportation mainly studies the driver’s comfort and vehicle handling stability,and the random vibration of the transformer itself has not been widely paid attention to.The fundamental reason is that the experiment is difficult,and the experience can only be accumulated by actual transportation.Therefore,this paper takes the semi-trailer train system transporting large transformers as the main research object,and uses the theory of random vibration and on-board dynamics to study the system response caused by random excitation.The specific research content of the thesis is as follows:In view of the infinite problem of the traditional pavement expression,the method of adding the lower cutoff circle frequency was proposed according to the actual situation,and the random excitation mathematical model was established and improved by using the filtering white noise method,and the simulation and verification were carried out in Matlab/Simulink.On this basis,combined with the 8-axis semi-trailer train combination studied in this thesis,a multi-axis stochastic excitation model was established by using the relative time delay principle,and the simulation and verification were carried out.The research results showed that the simulation model established by this method was used as the random excitation input for random vibration analysis.In order to study the overall model of the transformer-semi-trailer system,it was subdivided into the suspension-wheel system model,focusing on the study of the main part of random vibration transmission,by analyzing the suspension performance indicators to get three focused random vibration responses.Then a 2-degree-of-freedom model of the suspension system was established to solve the correlation amplitude-frequency characteristics,and then the simulation analysis was carried out in Matlab/Simulink,and the root-mean-square statistical value of random vibration analysis was proposed.Then,the mechanical system that can transmit random excitation to the transformer was retained by reasonable simplification of the 8-axle semi-trailer train,including the saddle structure which was often neglected.The 12-DOF dimensional parametric dynamics model of the transformer-semi-trailer system was established,and the matrix transformation was carried out.The dynamic response of the whole vehicle system was calculated by the solution idea of the suspension-wheel system.The results showed that this simplified method was not only accurate,but also much more efficient than the direct vehicle analysis.It can be used as a mechanical system model for random vibration analysis.The numerical simulation solution of the mathematical model was compared with the actual transportation results by Matlab to prove that the simulation results were consistent with the actual results and within the early warning range.The causes of the simulation errors were analyzed and the error threshold was set.Then,the sensitivity analysis was carried out in Isight to judge the influence factor weight of acceleration and angular acceleration response at the transformer,and complete the random vibration analysis in the transportation process of large transformer.The results showed that the simulation model established by random vibration analysis can accurately reflect the actual transportation situation,replace the actual transportation simulation experiment,reduce the experimental cost,and the analysis results of vibration impact factors were convenient for the subsequent vibration optimization scheme weighing selection.