Power supply device, system and method

The present invention relates to a power supply device, system and method, and relates to the technical field of communication. The power supply device comprises: a photoelectric composite plug, wherein a plug optical fiber interface, a plug power supply interface and a plug power supply grounding interface are arranged on the photoelectric composite plug; and a photoelectric composite socket provided with a socket optical fiber interface, a socket power supply interface and a socket power supply grounding interface which respectively correspond to the plug optical fiber interface, the plug power supply interface and the plug power supply grounding interface in quantity and position, wherein the contact surface of the plug optical fiber interface and the socket optical fiber interface is plated with a metal layer which is used to transmit authentication electrical signals of the photoelectric composite plug or the photoelectric composite socket. The power supply device can be connectedwith an unmanned aerial