A system configured to avoid a power shortage while a vehicle is traveling is provided. A voltage measurement device includes a relay, a first voltage measurement unit measures a first voltage applied to the power supply circuit, a second voltage measurement unit, a power supply circuit, and a control circuit. The power supply circuit is indirectly connected to a direct current bus. A first end of the relay is connected to the direct current bus, whereas a second end is connected to the power storage device. The control circuit, controls opening and closing of the relay, and closes a path between the first end and the second end when the first voltage is lower than or equal to a first threshold value. The second voltage measurement unit measures a second voltage applied to the second end at least when the relay is in an open state.