Arc Resistance Enhancement of Converter Transformer Tank Through Structural Improvements: Simulation and Experimental Validation

Abstract

Currently, limited research exists on the structural response and protection methods of the converter transformer tank for ± 800 kV ultra-high voltage direct current transmission project to high energy arc faults. This research investigates the dynamic response and the vulnerable areas of the ultra-high voltage converter transformer under the 50 MJ arc fault. It is found that the horizontal weld of the tank and the vertical weld of the tank are high strain concentration areas. Based on this, a design scheme for strengthening the weak areas of the transformer is proposed and the improvement effect is analysed via simulation. The results demonstrate that the improvement measures effectively reduce the strain level of the areas. In addition, the traditional transformer and the improved transformer are scaled down equivalently for experimental testing. To this end, mechanical structure, electrical circuit and data acquisition systems are established. The experimental results demonstrate the protective efficacy of the proposed measures, achieving peak strain reductions of 25.3% at the horizontal weld and 26.4% at the vertical weld.