The role of ring main unit

The function of the ring main unit is to contact the ring network line to improve the power supply reliability of the line, such as ring network line closing operation or ring network line load cutover, etc. The ring main unit is used in different parts of the ring network, and the classification is also slightly different, mainly including the incoming ring main unit, the outgoing ring main unit and the contact ring main unit.

Load switch classification of ring main unit

The main electrical components of the ring main unit are load switches and fuses. According to the different load switches, the ring main unit can be divided into vacuum load switch type and sulfur hexafluoride load switch type. At present, it is more common to use SF6 load switches for ring main units. This is because SF6 load switches are easy to achieve three working positions, that is, connecting, disconnecting and grounding.

Application environment classification of ring main unit

The ring main unit can be divided into indoor ring main unit and outdoor ring main unit according to the application environment. The indoor ring main unit is used for power distribution on the high voltage side. If necessary, the indoor ring main unit can also be equipped with a circuit breaker to ensure the smooth and safe switching on and off of the power grid. The indoor ring main unit is mainly composed of incoming cabinet, metering cabinet, PT cabinet, transformer outlet cabinet, etc.

The outdoor ring main unit is used in urban power grids, mostly using SF6 insulation and load switches. The outdoor ring main unit has a high level of anti-corrosion, and has a certain degree of waterproof and moisture resistance, which can withstand the more complex outdoor working environment.