The SF6 load break switch is an excellent load switch. In addition to its long electrical life and strong breaking force, it has the same advantages as the vacuum load switch. Its outstanding advantage is that it is easy to achieve three working positions (connected, disconnected, and grounded). Current (inductance, capacitance) breaking, strong resistance to severe environmental conditions. It is suitable for popularization and application in urban and rural medium-voltage distribution networks. The load break switch is a kind of switching device with a simple arc extinguishing device. The load break switch that uses SF6 gas as insulation and arc extinguishing medium is called SF6 load break switch. It can be used for switching and breaking load current and overload current, or as switching and disconnecting no-load circuits, no-load transformers and capacitor banks, all three-position load switches with the functions of connecting, disconnecting and grounding have the characteristics of simple structure and low price. But the load switch cannot disconnect the short-circuit current.
The SF6 load break switch + fuse combination electrical appliance is the SF6 load break switch to bear the overload current (this overload current is still within the range of the load switch rated breaking current for the SF6 load break switch) and the closing and breaking of the normal operating current. And it is also required to undertake the breaking of "transfer current". The short-circuit protection and overload protection of the high-voltage side of the transformer are borne by the high-voltage current-limiting fuse. At this time, a set of SF6 load break switches and three fuses with triggers, as long as any one of the triggers is activated, its linkage mechanism will automatically open the load switches at the same time. The organic combination of the two can meet the requirements of various normal and fault operation protection of the power distribution system.
Indoor SF6 Load Break Switch Structure
1. The load break switch and the combined electrical appliance are composed of the same insulated shell switch body, their own spring operating mechanism, the fuse contact base and the fuse action impact trip system.
2. The upper and lower enclosure are injected with epoxy resin to form an inflatable cavity. The common movable contact rotates to complete the three working states of "closing-opening-grounding" in sequence. On the basic manual spring energy storage operating mechanism Electric closing and opening can be installed to realize remote control operation for users to choose.
3. The position indicating device is directly connected with the driving shaft of the moving contact, indicating that the working position of the moving contact is absolutely reliable.
4. There is a safety diaphragm at the rear of the enclosure. When an accident may occur inside the arc extinguishing chamber and the pressure is too high, the over-pressure gas can break through the diaphragm and be released, thereby ensuring personal safety.
5. Load break switch and grounding switch, grounding switch and front door have reliable mechanical interlock.