A Fast Actuation Mechanism and Energy-Effective Driving Method for Pulse-Closers

Abstract

When a recloser detects fault currents in electric power distribution lines, it breaks the line and then restores the line after several fault tests. To check whether fault remains, the recloser performs CO operations (opening the contacts after reclosing them for a while). In this operation, the fault currents flow into the line, potentially causing damage to equipment connected to the line. Therefore, reducing the current-carrying time during the fault test is desirable, but this reduction is difficult because of the slow actuation mechanism of reclosers. In this article, a novel actuation mechanism combining a permanent magnetic actuator (PMA) and a solenoid actuator (SA) is proposed. During the CO operations for the fault tests, the proposed mechanism can rapidly break the closed contacts by hitting the moving contact with the SA. To increase the energy efficiency of the actuation mechanism, a distinctive PMA driving method is also proposed; it weakens the strong holding force of the PMA using assistive magneto-motive force (MMF). The structure and configuration of the proposed mechanism are explained. The performance of the mechanism and the effectiveness of the driving method are studied through cosimulations. Finally, a prototype is developed, and its practicality is verified through experiments.