Influence of Box-in Structure on Heat Dissipation Performance of UHV Converter Transformer

The Box-in structure is a structure used to reduce the noise effect of the converter transformer, but it also brings about the problem of reduced heat dissipation performance of the converter transformer. To study influences of Box-in structure on the heat dissipation and temperature distribution of Ultra-High Voltage(UHV) converter transformers so as to guide the heat dissipation of converter transformer and ensure its safe and stable operation, the following workwas done in this paper: Based on the finite element principle, the commercial software COMSOL was used to establish the electromagnetic-thermal-flow field simulation model of the converter transformer and its surrounding environment. Then, the influence of the Box-in structure on the temperature rise of the converter transformer and its surrounding environment under different ambient wind speeds was analyzed. After the above work, the following conclusions were obtained: the existence of the box-in structure significant reduces the convection heat dissipation capacity of the converter transformer box wall, resulting in that when the converter transformer with Box-in structure is compared with the one without Box-in structure, its average box wall temperature is 3.7K higher, and the local temperature is 7.7-17.55K higher; the hot-spot temperature rise of the converter transformer box wall decreases with the increase of ambient wind speeds. The research results obtained in this paper can be used to guide the heat dissipation of the box-in structure UHV converter transformer to ensure its stable operation.