High-Voltage Ring Main Units
High-voltage ring main units (HV RMUs) can improve power supply reliability, allowing users to obtain power from two directions. Generally, equipment that connects the power supply network into a ring structure is called a high-voltage ring main unit. In AC 10kV power distribution systems such as ports and high-rise buildings, due to the small load capacity, their high-voltage circuits are usually controlled by load switches or vacuum contactors, and equipped with high-voltage fuses for protection. This system typically adopts a ring network for power supply, and the high-voltage switchgear used is commonly referred to as a high-voltage ring main unit in practice.
In addition to supplying power to the local substation, the high-voltage bus of the HV RMU also needs to carry the through current of the ring power supply network (i.e., the current that supplies power to adjacent substations through the bus of the local substation). Therefore, the cross-sectional area of the high-voltage bus of the HV RMU should be selected based on the sum of the load current of the local substation and the through current of the ring network.
Solid Insulated Ring Main Units
Solid insulated ring main units (solid-insulated RMUs) are known for their high operational safety. They are available in standard cabinet types with 2 to 6 units as well as expandable cabinet types. Both the electrical and mechanical parts of the RMU adopt fully enclosed metal enclosures, which effectively shield against environmental influences.
All components are made of materials acceptable to the natural environment and contain no SF₆ gas. All primary electrical components and mechanical devices are installed in fully enclosed enclosures, which effectively prevent dust, moisture, and other adverse environmental factors from affecting the operation of the RMU.
On the basis of the original products, expandable cabinet types have been developed, facilitating users to expand lines and add functions such as metering. These units can be used in fully automated power networks.
This article is compiled and edited by DAYA Electric Group Co., Ltd. (https://www.hygraphics.com/). Please indicate the source when reprinting.