Core safety and efficient equipment in the medium-voltage power distribution field

The 12kV indoor SF₆ load switch is a three-phase AC high-voltage load switch with a rated voltage of 12kV, suitable for indoor installation. It uses SF₆ gas as the insulating and arc-extinguishing medium. It is mainly used to open and close the load current in the power system, as well as to close the short-circuit current (it cannot open the short-circuit current and needs to be combined with a fuse to achieve short-circuit protection). At the same time, it can achieve the isolation and grounding functions of the line, providing safety protection for the maintenance of distribution equipment.

The core working principle of this switch is based on the excellent properties of SF₆ gas: SF₆ gas has extremely strong insulation strength, being more than 2.5 times that of air. In a sealed gas chamber, it can effectively isolate the live parts from the casing, preventing the occurrence of leakage accidents. During the arc-extinguishing process, when the switch is opened, the moving and static contacts separate, generating an arc. The SF₆ gas is heated by the arc and undergoes ionization, absorbing a large amount of arc energy. At the same time, the gas convection and cooling effects are utilized to quickly extinguish the arc, avoiding the burning of the contacts or triggering equipment failures. Most products adopt a permanent magnetic field arc-extinguishing method. When opening the switch, the arc rotates and elongates in the electromagnetic field generated by the permanent magnet, further improving the arc-extinguishing efficiency, ensuring low operating overvoltage, stable opening performance, and even achieving excellent performance of opening the rated current at zero pressure.

The equipment usually integrates the three functions of "closing, breaking, and grounding". Through mechanical interlocks, the operation sequence is strictly regulated to ensure that "the equipment cannot be closed without grounding, and the load switch cannot be closed with the grounding switch not disengaged". This fundamentally avoids potential safety hazards caused by incorrect operations and ensures the safety of personnel and equipment operation.