A superconducting electrical power distribution system has a superconducting bus bar and one or more bus bar thermal conductor lines extending in thermal proximity along the bus bar to receive heat from the bus bar over the length of the bus bar. The system further has superconducting cables electrically connected to the bus bar at respective electrical joints distributed along the bus bar. The system further has a cryogenic cooling sub-system. The system further has a network comprising first and second thermal conductor lines, each line comprising a cold end which is cooled by the cryogenic cooling sub-system, and an opposite hot end, whereby heat received by each line is normally conducted along the line in a direction from its hot end to its cold end.