POWER SYSTEM

A power system includes a central unit, a zone unit capable of communicating with the central unit, and a downstream electric wire configured to electrically connect a predetermined downstream unit to the zone unit. A central processor of the central unit executes processing including transmitting electric wire characteristic data stored in a central storage device to the zone unit at a predetermined timing. A zone processor of the zone unit executes processing including writing the electric wire characteristic data transmitted from the central unit into a zone storage device in response to reception of the electric wire characteristic data, and determining whether to turn a semiconductor switch coupled to the downstream electric wire to an OFF state, based on the electric wire characteristic data written into the zone storage device and the current detected by a current sensor.