Ring main unit working principle

The ring network 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 the main line passes through the high-voltage switch to distribute power. The advantage of this is that each power distribution branch can take power from its left trunk and also from its right trunk. When the left main line fails, it continues to receive power from the right main line, and when the right main line goes out, it continues to receive power from the left main line. For a power distribution branch, it is similar to the benefits of dual power supply, thus improving the reliability of power supply.

Ring main unit means that each distribution branch is equipped with a switchgear (outgoing switchgear), and the busbar of this switchgear is also a part of the ring line. In other words, the ring trunk line is composed of the busbars of each outlet cabinet. Each outlet cabinet is called a "bad network cabinet". In fact, the meaning of "ring network" cannot be seen by taking out a ring network cabinet alone.

The rated currents of these ring main units are not large, so the high-voltage switch of the ring main unit is generally not complicated to open the circuit and adopts a simple structure of high-voltage load switches with high-voltage fuses. In other words, the high-voltage switch in the ring main unit is generally a load switch. The ring main unit uses a load switch to operate the normal current and a fuse to cut the short-circuit current. The two combine to replace the circuit breaker. Of course, this can only be limited to the capacity of one walk.

Such switchgear can also be used in the distribution system of non-ring network structure, so with the wide application of this switchgear, "ring network cabinet" has jumped out of the category of ring network power distribution and generally refers to load switch High-voltage switchgear for the main switch.