赵紫薇,汪友华,火彩玲.变压器环形铁芯建模和剩磁测量[J].电测与仪表,2023,60(7):116-121. ZHAO Ziwei,WANG Youhua,HUO Cailing.Toroidal iron core modeling of transformer and residual flux density measurement[J].Electrical Measurement & Instrumentation,2023,60(7):116-121.
变压器环形铁芯建模和剩磁测量
Toroidal iron core modeling of transformer and residual flux density measurement
When the large transformer performs no-load closing operation, magnetizing inrush current may be resulted for the residual flux exists in the iron core, and thus the transformer perhaps fail to connect with the power grid. A novel method for analyzing and measuring residual flux in the closed iron core is proposed in this paper, which is based on the positive and negative DC voltage excitation method. The principle of residual flux generation is introduced, and then, considering the hysteresis characteristic of magnetic material, a toroidal iron core simulation model is established based on Jiles-Atherton (J-A) model. By applying DC voltage with the same magnitude but different polarity to the winding on the toroidal iron core, two different response currents can be obtained. Based on magnetic field and circuit transient analysis method, the residual flux direction can be determined, and then, the corresponding relationship between the response current and the residual flux can be also found. This method can accurately measure the value and direction of the residual flux when it has little effect on the initial residual flux in iron core. Finally, the residual flux in toroidal iron core is measured by the self-built experimental platform, and the rationality of the simulation results are verified.
