Development of 72/84 kV dead-tank VCB with rated normal current of 3000 A

A 72/84 kV dry-air insulated dead tank type VCB with rated normal current of 3000 A has been developed. The rated normal current of the conventional type is limited to 2000 A. We used thermal network analysis to design the 3000 A model. Based on the analysis results, the dimensions and materials of the conductors and contacts were modified and conditions to satisfy the temperature rise limit were determined. The results of temperature rise tests with a prototype model showed good agreement with the analysis results.