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Date：12-19-2022
Ring network cabinet is commonly known as SF6 load switch and SF6 load switch + fuse combination appliance used in ring network line or terminal. SF6 load switch is an excellent load switch experienced by many users in recent years. In addition to the advantages of long electric life, strong breaking force and vacuum load switch, its outstanding advantages are easy to realize three working positions (on, off and ground), small current (inductance, capacitance) to open and break, and strong ability to resist harsh environmental conditions. It is suitable to popularize and apply in urban and rural medium voltage distribution network.
Ring network cabinet is generally divided into two types: air insulation and SF6 insulation. It is used for dividing and closing load current, opening and breaking short circuit current and transformer no-load current, and charging current of overhead line and cable line at a certain distance. It plays a role of control and protection, and is an important switching equipment for ring network power supply and terminal power supply. In the cabinet body, the load switch equipped with air insulation mainly includes gas production type, pressure type and vacuum type. The load switch equipped with SF6 insulation is SF6 type. Because SF6 gas is closed in the shell, the partition fracture formed by it is not visible. The load switch in the ring network cabinet generally requires three stations, that is, cut off the load, isolate the circuit, feasible by grounding. Gas production type, pressure type and SF6 type load switch is easy to achieve three stations, and the vacuum arc extinguishing chamber can only be broken, can not be isolated, so the general vacuum load ring network switch before the load switch to add an isolation switch, in order to form an isolation break.
The load switch is a kind of switching appliance with a simple arc extinguishing device. The load switch that uses SF6 gas as insulation and arc extinguishing medium is called SF6 load switch. It can be used to turn on and off load current and overload current, and can also be used to turn on and off no-load lines, no-load transformers and capacitor banks, etc. The three-bit load switch with the functions of on, off and ground has the characteristics of simple structure and cheap price. Only the load switch cannot disconnect the short circuit current.
SF6 load switch + fuse combination appliance is by SF6 load switch to bear overload current (the overload current for SF6 load switch is still within the range of load switch rated off current) and normal working current closing and breaking, and also requires to bear the “transfer current” off. The high voltage fuses are responsible for the short circuit protection and overload protection on the high voltage side. At this time, a group of SF6 load switch and three fuses with triggers, as long as any trigger action, its linkage mechanism will make the load switch three-phase automatic switch. The combination of the two can meet the requirements of power distribution system operation protection under normal and fault conditions.
Ring network cabinet can be divided into indoor ring network and outdoor ring network
The indoor loop network is generally used for the power distribution of the high voltage side. It is composed of the incoming line cabinet, the metering cabinet, the PT cabinet and the transformer outlet cabinet. For the users with high power requirements, the incoming line must adopt the dual power switch cabinet. The seventh floor said that “now some people will load switch and fuse combination of high voltage switch cabinet called ring network cabinet, mainly is easy to distinguish with circuit breaker switch cabinet” is not accurate, ring network cabinet also has a circuit breaker program
Outdoor ring network is generally used in urban power grid, using common box type SF6 ring network cabinet, the biggest characteristic of this type of cabinet is that the protection level is high, can do IP67, suitable for outdoor, and can be soaked in water for a short time. The scheme of loop network power supply generally adopts one loop in, one loop out, two or three times to do the outgoing circuit, that is, the formation of hand in hand loop network power supply mode.
In order to ensure the reliability and continuity of power supply, two inlet lines are used to supply power, which forms a ring. SF6 load switch, 3 stations (closing, opening, grounding), branch line, transformer.
