| 摘要 |
A direct current (DC) circuit breaker comprises a main circuit 302 and transient circuit 308 configured to carry respective main and transient-path currents between live and load terminals 304,306. When the main-path current through a first solid-state switch 312 exceeds a first threshold, a second solid-state switch 316 in the transient circuit is closed, after which the first switch is opened, diverting the main-path current to the transient circuit. A main contactor 310 is then opened when the main-path current falls below a second threshold, after which the second switch 316 is opened. Finally, when the transient-path current falls below the second threshold, an auxiliary contactor 314 in the transient circuit is opened. The transient circuit may further comprise a voltage clamping device 318 and a capacitor 320 connected in parallel with the second switch. The first and second switches may be, respectively, a low-voltage MOSFET and a high-voltage IGBT. The main and auxiliary contactors may be integrated as a single three-pole mechanical contactor (408, figure 4). A high-voltage semiconductor switch 322 may be coupled between the main circuit and ground, and be configured to remain open in normal operation and close upon detection of a high-impedance fault. |
