不同预紧力下变压器绕组轴向振动模态分析

Axial vibration modal analysis of transformer windingsunder different levels of pre-compression

根据电力变压器绕组的轴向振动的弹簧质量系统数学模型并考虑了电力变压器绕组的轴向振动的非线性特点,建立了轴向质量、弹塑性绝缘垫块和夹件组成的电力变压器绕组的模态仿真系统,给出了电力变压器绕组在不同预紧力下的轴向振动模态分析的方法,得出每一阶模态具有特定的固有频率和模态振型。指出了电力变压器绕组轴向预紧力的变化与其轴向振动固有频率变化之间的关系,并通过有限元软件ANSYS进行仿真分析和瞬态激振法进行实验验证。结果表明,仿真计算和实验数据相符合。建立了绕组的不同预紧力与固有频率变化之间的关系数据库,为电力变压器绕组结构设计时固有频率避开轴向电磁力的频率提供了理论和实验依据。

According to the axial vibration of mass-spring system models of power transformer windings and its nonlinear characteristics, the modal simulation system of the power transformer windings, which composes of axial mass, elastoplastic insulation spacer blocks and clamps, is developed. The modal anal- ysis method of power transformer windings under different axial levels of pre-compression is given, and the specific natural frequency and modal order of each step mode are obtained. The relations between the changes of axial pre-compression and axial vibrations natural frequencies on the windings are investigated by ANSYS simulink computation and transient excitation vibration method. The results show that the sim- ulation calculation agrees with the experimental data well. The database in different levels of pre-com- pression and natural frequencies is established, which provides the experimental and theoretical founda- tion for designing of transformer windings structure, in which axial natural frequency will avoid the fre- quency of the axial electromagnetic force.