The ring main unit cabinet refers to the ring power distribution network, that is, the power supply main line forms a closed loop, and the power supply supplies power to the ring main line, and then distributes power from the main line all the way through the high-voltage switch. The advantage of this is that each power distribution branch can take power from its left main line, and it can take power from its right main line.

　　 The high-voltage ring main unit is to provide power supply reliability by connecting the high-voltage switch cabinet busbars into a closed loop. The user obtains power from two directions to become the ring main unit.