Transitional processes at switching-off unloaded power transmission lines by modern circuit-breakers and their computer simulation

The article presents results of transitional processes computer simulation at switching-off unloaded power transmission line of rated voltage 220 kV by auto-compression (SF6) circuit-breakers. Transitional voltages (voltage across the line terminals and recovery voltage) at switching-off were calculated and studied in the research carried out. There was also considered dependence between transitional voltages magnitudes and power transmission lines lengths. There were studied some computational peculiarities of the problem under consideration. In particular, the numbers of pi-sections provided satisfactory adequacy of lines equivalency at computer simulation for their typical lengths were determined. There were also estimated optimum simulation parameters provided stability of transitional regime parameters.