Working principle of high-voltage ring main unit

The ring network refers to the ring power distribution network, that is, the power supply main line forms a closed loop. The power supply supplies power to the ring main line. From the main line all the way through the high-voltage switch, the advantage is that each power distribution The branch can take power from its left main line, and it can take power from its right main line. When the left main line fails, it continues to receive power from the right main line, and when the right main line fails, it continues to receive power from the left main line. In this way, even though the main power supply is single-circuit power supply. However, from the perspective of each power distribution branch, benefits similar to dual power supply are obtained, thereby improving the reliability of power supply.

The so-called "high voltage ring main unit" means that each distribution branch is equipped with a switchgear (outgoing switchgear). The bus of this switchgear is also a part of the ring trunk, that is, the ring trunk is from each outgoing cabinet The busbars are connected together, and each outlet cabinet is called a "high-voltage ring main unit". In fact, if you take out a high-voltage ring main unit separately, you cannot see the meaning of "ring network".

The rated current of these high-voltage ring main units is not large, so the high-voltage switch of the high-voltage ring main unit generally does not use a circuit breaker with a complicated structure but a high-voltage load switch with a high-voltage fuse with a simple structure, that is, the high-voltage ring main unit The high-voltage switch in the medium is generally a load switch. The high-voltage ring main unit uses a load switch to operate the normal current and a fuse to cut the short-circuit current. The combination of the two replaces the circuit breaker. Of course, this can only be limited to a certain capacity.

Such a ring main unit can also be used in a non-ring network structure power distribution system, so with the widespread application of this ring main unit. "High-voltage ring main unit" jumps out of the scope of ring power distribution and generally refers to the high-voltage ring main unit with load switches as the main switch.