Research On The Correlation Between Loose Deformation And Vibration Signal Of Power Transformer Windings

Power transformer was one of the most important equipment in the power system,it operated with the safe condition was important for the power system.And the winding loose deformation was one of the common type of winding fault,due to the power transformer had the cumulative effect,if the loose winding deformation was not found in time,the winding deformation would lead to the mechanical stability fault.which would reduce the anti-short circuit ability.So it was important to the transformer operating with the detecting the winding loose deformation in time.It detected the winding deformation fault from the winding mechanical stability,when the winding was loose,it mechanical structure will change,and it modal parameters would change all the time,comparing with the normal condition.But the change of the above parameter could be detected with the vibration signal frequency response function.Modal was the natural vibration characteristic of structure,which will change with the structure.So it could detect the transformer winding deformation with the vibration response function.Vibration frequency response method was used to the winding loose fault,it should specify the modal parameter change trend,which would lay foundation for the later research.To achieve the above research target,firstly,it analyzed the common winding deformation and the faults reason,it summarized the application of the vibration frequency in the fault detecting,and it specify the feasibility of the method in the winding fault detecting.It summarized the current modal analysis method,when it made the research of the modal parameter change trend,and it specify the research status and basic research method,and it introduced the experiment analysis system.In order to research the modal parameter change trend with the above analysis,firstly it made the finite element analysis of transformer winding to the numerical modal analysis,and it established the above four simulation model in normal and loose deformation.Through the simulation model of initial normal state of power transformer winding,the modal parameters change trend of natural frequency was obtained.In order to further understand the looseness fault modal characteristics of the power transformer winding,50%Fn pre-tightening force for the power transformer winding looseness fault was carried on the test,and then Fn was carried out different pre-tightening force in the experiment,through the change of the pre-tightening force,it found the neglect modes for looseness fault of transformer winding was more sensitive,and its inherent frequency variation changed more.And in order to corresponding to the research of finite element simulation,it carried the research platform for the entity of the transformer winding experimental modal.And it made the modal experiment for the normal and 50%Fn pre-tightening force test,and it got the vibration frequency curve.Finally in order to get the modal parameter from the winding vibration frequency curve,so that it could detect the winding deformation from the change of modal parameter,it came up with the parameter decomposition algorithm,and it compared the simulation result with test result on the basis of the above research,it showed the correction of the ANSYS simulation result,it also analyzed the vibration change trend in the loose winding fault,it laid a foundation for the vibration frequency response testing system in the transformer winding deformation.