The disconnect switch has no special arc extinguishing device, and its arc extinguishing ability is weak. The load switch is an on-off switch with a dedicated arc extinguishing contact, an arc extinguishing device and a spring circuit breaker. Vacuum circuit breakers have reliable arc extinguishing devices.
Because disconnect switches lack a particular interrupting device and have a low interrupting capacity, they are often employed to isolate voltage and cannot connect or disconnect the load current. The principal purpose of pole mounted disconnect switch is to isolate the supply voltage when electrical equipment is shut down for maintenance, as well as to create an obvious separation point to protect the safety of maintenance people on the job.
A load break switch sf6 combines a specific arcing contact, an arc extinguishing mechanism, and a spring-loaded circuit breaker into one device. A load break switch is structurally similar to a disconnector (both have apparent break points when detached), but it can also be used to open and stop circuits, much like a circuit breaker. A load break switch, on the other hand, can only open and close a load current or open and close an overload current, but a circuit breaker can control any circuit. As a result, it is only used to cut and tun on circuits under normal operating conditions, rather than to break short-circuit fault currents.
It must, however, be built to pass the short-circuit time fault current without causing damage. The load break switch's interrupters and contacts are designed to cut and connect the load current. In most circumstances, the load break switch should be used in conjunction with a high-voltage fuse, with the latter's job being to cut off the short-circuit fault current. Load break switches have a higher frequency of opening and closing, as well as a longer operating life, than circuit breakers.
The advantages of load break switch are less expensive and are typically used for distribution lines below 10kV. Air, pressurized air, SF6, and vacuum arc extinguishing are their arc extinguishing methods. The varieties and quality of load break switches have evolved and improved as science and technology has progressed. When the circuit is running properly, the load break switch contains a simple arc extinguishing device with limited arc extinguishing capability, which is utilized to connect or cut off the load current, but not to cut off significant short circuit currents when the circuit is served. After disconnection, the load break switch has a visible disconnection point, which is one of its characteristics.
When the circuit is running normally, the arc extinguishing capacity of a reliable arc extinguishing device is very strong, and it is used to connect or cut off the load current, and in the event of a fault in the circuit, pole mounted auto recloser is used to cut off the massive short-circuit current. According to the arc extinguishing medium, high-voltage circuit breakers can be classified as multi-oil arc extinguishing circuit breakers, oilless circuit breakers, vacuum circuit breakers, sulphur hexafluoride circuit breakers, and so on.