What Are The Differences Between Load Switches, High Voltage Disconnect Switch And Vacuum Circuit Breakers? Where Are They Used?
High Voltage Disconnect Switch plays a role of control and protection in the power system. It can put part of the power equipment or line into or out of operation according to the needs of the power grid operation, and can also quickly cut off the faulty part from the power grid when the power equipment or line fails, so as to ensure the normal operation of the fault-free part of the power grid and the safety of equipment and operation and maintenance personnel.
According to the classification of functions, high-voltage switchgear generally includes high-voltage circuit breakers, High Voltage Disconnect Switch, load switches, fuses and high-voltage switch cabinets. Among them, circuit breakers, High Voltage Disconnect Switch, and load switches all carry the rated current of the circuit in the primary circuit, control and protect the circuit. What are their specific functions? What is the difference? Let's take a look.
What is a load switch?
It is a control device with a simple arc extinguishing device that can open and close the circuit with load. It can switch on and off a certain load current and overload current, but cannot disconnect the short-circuit current. It must be used in series with a high-voltage fuse to cut off the short-circuit current with the help of a fuse.
Function of load switch
1. Opening and closing function
Since it has a certain arc extinguishing ability, it can be used to open and close load current and overload current of a certain multiple (usually 3-4 times); it can also be used to open and close no-load transformers with a larger capacity than High Voltage Disconnect Switch, longer no-load lines, and sometimes used to open and close large-capacity capacitor banks.
2. Substitution function
The combination of load switch and current-limiting fuse in series can replace the circuit breaker. That is, the load switch is responsible for opening and closing overload currents less than a certain multiple, while the current-limiting fuse is responsible for opening and closing larger overload currents and short-circuit currents.
3. The load switch that is combined in series with the current-limiting fuse is called "load switch-fuse combination electrical appliance" in the national standard. The fuse can be installed on the power supply side of the load switch or on the power receiving side of the load switch. When it is not necessary to replace the fuse frequently, the former arrangement should be adopted so that the load switch can also serve as the function of High Voltage Disconnect Switch and be used to isolate the voltage applied to the current limiting fuse.
