PURPOSE: To facilitate the instantaneous phase changeover while a large excitation rush current is eliminated from a distribution system.

CONSTITUTION: A first witch 2 is connected to a distribution line 1 in parallel with the cut off point of the distribution line 1. A non-contact switch 3 which is closed with a high speed continuously after the first switch 2 is opened and a second switch 4 which is in parallel with the non-contact switch 3 are connected between the cut off phase and the changeover phase of the distribution line 1 at the position on a load side from the cut off point. Further, a voltage detecting means 6 is attached to the changeover phase and, when the voltage of the changeover phase reaches the peak value of a sine wave first time after the first switch is opened, the non-contact switch 3 is closed to avoid a large excitation rush current.