The invention provides a standalone power bus system comprising at least one standalone power bus unit. Each standalone power bus unit comprises a first convergence board, a second convergence board, a power bus positive line, a power bus negative line, a first lug, and a second lug, wherein the power bus positive line and the first lug are connected to the back of the first convergence board, the power bus negative line and the second lug are connected to the back of the second convergence board, the first convergence board and the second convergence board are respectively provided with bonding wire slots, the power bus positive line and the power bus negative line are respectively equipped with binding posts, and the first lug and the second lug are respectively connected with a transmission line. A third lug and a fourth lug are respectively arranged on the first convergence board and the second convergence board of any standalone power bus unit. Each third lug is connected with a power controller bus, and each fourth lug is connected with a power controller loop. The satellite-borne cable network is simplified, and the mode of standalone multi-channel power supply input is optimized.