Overvoltage phenomena associated with virtual current chopping in three phase circuits

Switching of three phase load currents with low power factors, such as encountered in arc furnace installations can result in a series of reignitions and clearings. Depending on the switch performance and system parameters the switching transients may involve one, two, or three phases. The effect of virtual current chopping which can lead to line to line overvoltages is described. The phenomena are explained for simplified conditions, more complex situations are handled by digital computer studies.