POWER SUPPLY DEVICE AND POWER SUPPLY SYSTEM

The present specification relates to a power supply device and a power supply system which enable uninterruptible power supply, wherein a circuit breaker is provided in a power bus to which a plurality of power supply devices are connected, so as to switch on/off the connected power supply devices, and thus the UPS function can be performed among the plurality of power supply devices by opening or closing the circuit breaker according to various situations occurring in the system to control power reception and supply.