Electric railcar power feeding system, power feeding device, and power storage device

An electric railcar power feeding system in an embodiment includes a power storage device, a rectifier, and an emergency power supply. The power storage device is connected to a feeder line for an electric railcar. The rectifier converts alternating-current power of a first power system to direct-current power and supply the direct-current power for the feeder line. The emergency power supply supplies power of a second power system different from the first power system for the feeder line.