Working Principle Of High-voltage Load Switch

The working principle of high-voltage load switch is similar to that of circuit breaker. Usually equipped with a simple arc extinguishing device, but its structure is relatively simple. The figure shows a compressed air high-pressure load switch, which works as follows: when the switch is opened, the main shaft rotates clockwise under the action of the opening spring, and on the one hand, the piston moves upward through the crank slider mechanism to compress the gas; On the other hand, through a transmission system composed of two sets of four-bar linkage mechanisms, the main blade is first opened, and then the arc extinguishing blade is pushed to open the arc contact. The compressed air in the cylinder blows out the arc through the nozzle. When closing, the main switch and arc extinguishing switch are rotated clockwise simultaneously through the main shaft and transmission system, and the arc contact is closed first; The spindle continues to rotate, causing the main contact to subsequently close. During the closing process, the opening spring simultaneously stores energy. Due to the inability of load switches to disconnect short-circuit currents, they are often used in combination with current limiting high-voltage fuses. By utilizing the current limiting function of current limiting fuses, not only can the task of disconnecting circuits be completed, but the thermal and electrical effects caused by short-circuit currents can also be significantly reduced.