Research On Core Loss And Winding Vibration Based On Magnetic Field Characteristics Of New Converter Transformer

With the vigorous growth of the power industry,DC transmission projects have a very important position in terms of power expansion and resource optimization.Due to the use of a series of non-linear power electronic devices such as thyristor converters in HVDC converter stations,many harmonic currents have passed through the converter transformer,causing the phenomenon that harmonic flux appears in the converter transformer.The loss of the iron core increases,and the amplitude of the electromagnetic force related to the winding increases,which causes the related vibration in the transformer to increase.The noise pollution situation is intensified,and the transformer winding may be severely deformed.The insulation-related function is affected.To some damage,reducing the use time of the transformer,and bringing many negative effects to the grid system.The new converter transformer to be explored in this paper relies on the unique technical method of filtering.The converter transformer uses a filtering technology to add a set of filtering device inside,which is connected at the valve side end to isolate the harmonics nearby,reduce the current flowing in the harmonics to the mesh side end,and effectively reduce the iron harmonic The magnetic flux can reduce the core loss and electromagnetic vibration at the same time,which serves the purpose of noise reduction.This thesis explores the explanation and analysis of the aspects related to the calculation and core vibration of the new converter transformer core loss,and roughly the following aspects:Based on ANSYS software sets up the winding 2D finite element model.In accordance with the field-circuit coupling analysis method,the circuit processing analysis model of the field-circuit coupling related to the converter transformer is made,and the winding current is used as the input excitation of the finite element processing analytical model.The core flux density distribution of the new converter transformer is calculated by finite element method,and the magnetic flux component and core loss and its characteristic harmonic loss of the core are obtained by post-processing.The comparative analysis can be concluded that the core loss and its characteristic harmonic loss are reduced after inputting the filter tuning device,which can effectively suppress the harmonic flux of the transformer core.According to the vibration analysis method,the model of the 3D finite element processing of the winding core is established.According to the Lagrange’s method,the magnitude of the electromagnetic force of the winding in the new converter transformer is solved,and the magnitude of the electromagnetic force is compared with the case where the filter device is not put into the filter device and the filter device is input.The transient dynamics analysis method is adopted,and the electromagnetic force amplitude is sequentially loaded into each relevant winding to solve the phenomenon of vibration movement of each winding in two different situations.By comparing and solving the solution,it can be obtained that the new converter transformer can effectively suppress the harmonic flux of the core,reduce the core loss and its characteristic harmonic loss,and help to suppress the electromagnetic vibration characteristics of the winding.Its filtering technology has a good application prospect for the field of DC transmission engineering.