重合闸工况下变压器绕组轴向动稳定性仿真研究

Simulation research on axial dynamic stability of transformer winding under reclosing condition

当重合闸重合于永久性故障时,会给变压器带来二次冲击,增加变压器损坏的可能性。对此,首先建立了三绕组变压器“高-中-低”运行方式下的漏磁场计算模型;之后建立了绕组线圈轴向振动的非线性模型,并提出线饼及垫块上所受轴向压力的动态计算方法;最后利用所建立模型对一台110 kV变压器在重合闸工况下的轴向强度进行评估。结果表明,重合于最劣工况时,变压器漏磁场增加,振动更为剧烈,作用于线圈及垫块上的力更大,变压器出现轴向不稳定的可能性增大。研究结果可为变压器重合闸工况校核提供依据。

Reclosing during a permanent fault subjects the transformer to secondary impacts,thereby increasing the likelihood of transformer damage.In this paper,a computational model for calculating the leakage magnetic field of a three-winding transformer operating in"high-medium-low"mode is first established.Subsequently,a nonlinear model for the axial vibration of winding coils is developed,and a dynamic calculation method for the axial pressure on the coils and spacers is proposed.Finally,the established model is utilized to evaluate the axial strength of a 110 kV transformer under reclosing operation conditions.The results indicate that during reclosing in the poorest operating condition,the leakage magnetic field of the transformer increases,vibrations become more intense,and the forces acting on the coils and spacers are greater,thereby increasing the possibility of axial instability in the transformer.These findings can provide a basis for the verification of operating conditions for transformers during reclosing.