The function of high-voltage ring main units (HV RMUs) is to improve power supply reliability by enabling users to obtain power from two directions. Typically, the power supply network is connected into a ring, a power supply mode referred to as "ring network power supply" for short.

In AC 10KV power distribution systems such as industrial and mining enterprises, residential communities, ports, and high-rise buildings, due to the small load capacity, the high-voltage circuits are usually controlled by load switches or vacuum contactors, supplemented with high-voltage fuses for protection. Such systems generally adopt ring network power supply, and the high-voltage switchgears used are customarily called high-voltage ring main units.

A ring network refers to a circular power distribution network, where the main power supply line forms a closed ring. The power supply source feeds electricity to this circular main line, and then distributes power outward through high-voltage switches branch by branch from the main line. The advantage of this configuration is that each power distribution branch can draw power from both the left and right main lines. If the left main line fails, the branch continues to receive power from the right main line; if the right main line fails, it draws power from the left main line. In this way, although the total power supply is a single circuit, each power distribution branch achieves the practical benefit similar to dual-circuit power supply, thereby improving the reliability of power supply.

This article is edited and organized by DAYA Electric Group Co., Ltd. (https://www.hygraphics.com/). Please indicate the source when reprinting.