Abstract
With the increasing power demands, size of the fault current in electrical grids is steadily increasing, and it exceeds the breaking capacity of circuit breakers. To effectively cope with these problems, a high-speed interrupter was suggested. The high-speed interrupter provides fault current with a bypass to a fault current limiter in case of accidents and consequently, fault current can be restricted. In this study, behavioral characteristics of high-speed interrupter were analyzed by accident types occurred in a distribution system. When accidents occurred, a and b contact of the high-speed interrupter were turned-off and then, turned-on. Accordingly, fault current flowed to the circuit connected to a current limiting element, and the fault current limiter restricted fault current to within a half-cycle. Nevertheless, the behavior of the high-speed interrupter was slowed down by a switching surge. As a result, fault current was confirmed to be restricted not to within the anticipated half-cycle, but to after a half-cycle. Moreover, the behavioral characteristics of the high-speed interrupter changed not only by accident types, but by behaviors of R, S, and T phases. This was due to the errors in stroke lengths of the high-speed interrupters, which resulted in a slight time discrepancy among three interrupters. In addition, the switching behaviors of the b and a contact were confirmed not to have coincided due to the switching surge; b contact behaved first and a contact followed. because of this, accuracy of stroke length and switching surges through the solenoid suction increases may be necessary to resolve.
