Method for switching phase lines of three-phase circuit and capable of preventing inter-phase short-circuit and phase change switch device

The invention relates to a method for switching the phase lines of a three-phase circuit and capable of preventing inter-phase short-circuit and a phase change switch device, which belong to the field of transformation and distribution devices. A phase line switch and a self-resetting single-phase switch are arranged in the shell body of the phase change switch; when load switching needs to be carried out, first the self-resetting single-phase switch is controlled to be off, and the external power supply of the phase change switch device is cut off; then the moving contact of an electric rotation switch is rotated and a 'one-from-three' rotation switch method is adopted, so that the phase sequence of the phase line input end of a single-phase power supply is switched to specified phase lines; and finally the self-resetting single-phase switch to be on, and the external power supply of the phase change switch device is recovered. Because the 'one-from-more' rotation switch method is adopted, the connection with a load end is cut off when in switching, the phenomenon that two phase lines are short-circuited when the phase change switch fails to work is thoroughly overcome, the whole switching process is safe and reliable, and the safety of power supply is improved. The invention can be widely applied to the field of low-voltage power supply and the operation of power grids.