新型HVDC换流变压器绕组振动抑制研究

Study on winding vibration suppression of new HVDC converter transformer

针对高压直流输电(HVDC)换流变压器的阀侧换流器产生大量谐波电流,导致过量谐波电流流过换流变压器绕组,使铁心由于谐波磁通过大而过饱和,引发换流变压器的铁心和绕组剧烈振动问题,对新型换流变压器绕组在谐波条件下的电磁振动进行理论研究。首先,基于三绕组变压器理论并考虑特征次谐波,求解新型换流变压器各绕组电流与负载电流的变换关系;然后,利用虚位移法求解绕组受到的电磁力,建立绕组及相应铁心的3-D有限元(FEM)模型,通过瞬态求解最终得到其电磁振动特性。最后,测试变压器的绕组振动,通过对比实测振动和有限元计算结果验证计算的可靠性。研究结果显示,感应滤波技术对绕组电磁振动的抑制效果显著。

Nonlinear loads in valve side of high-voltage direct current(HVDC)converter transformer produces a mass of harmonic currents,and DC magnetic bias phenomena also affects the converter transformer.As a result,harmonic currents in the windings and harmonic flux in the core of converter transformer increases,which leads to more serious vibration of windings and core.It has become a new problem in HVDC project.Winding electromagnetic vibration of a new converter transformer considering harmonic currents was studied.Transformation matrices from load currents to windings′currents were proposed and the electromagnetic forces of windings were calculated by Lagrange′s theorem.The 3-D finite element method(FEM)model of windings and core was established.Finally,the windings′vibration characteristics were determined by computing the FEM model with transient dynamic analysis method.Finally,the windings′vibration was tested,and the experimental data verified the correctness of the FEM simulation.The result reveals that the new HVDC converter transformer can suppress the windings′vibration.