METHOD, CIRCUIT BREAKER AND SWITCHING UNIT FOR SWITCHING OFF HIGH-VOLTAGE DC CURRENTS
First Claim
1. A method for switching off a high-voltage DC current from a voltage source delivering a nominal voltage by means of a circuit breaker including a semiconductor switching assembly and at least one mechanical switch in series, wherein the semiconductor switching assembly includes a plurality of semiconductor switches and a plurality of arresters in parallel to the semiconductor switches, the method comprising:
- switching off the semiconductor switching assembly to reduce current in the circuit breaker to a residual current; and
switching off the residual current by means of the mechanical switch, wherein;
the arresters have an added threshold voltage exceeding the nominal voltage;
the mechanical switch is arranged in a resonant circuit configured to generate an oscillating current through an arc in the mechanical switch after switching off the semiconductor switching assembly and opening the mechanical switch;
the oscillating current has an amplitude exceeding the residual current such that at least one current zero crossing can be generated in the arc of the mechanical switch; and
the method comprises extinguishing the arc during the current zero crossing.
8 Assignments
0 Petitions
Accused Products
Abstract
A high voltage DC circuit breaker includes a semiconductor switching assembly in series with a mechanical switch. When the semiconductor switching assembly is switched off due to a current fault, a residual current flowing through arresters of the semiconductor switching assembly is switched off by the mechanical switch. A capacitor arranged parallel to the mechanical switch leads to passive resonance effects, which in turn induce current zero crossings in its arc. The current zero crossings allow for reliable extinguishing of the arc. The mechanical switch can be an AC circuit breaker.
28 Citations
30 Claims
-
1. A method for switching off a high-voltage DC current from a voltage source delivering a nominal voltage by means of a circuit breaker including a semiconductor switching assembly and at least one mechanical switch in series, wherein the semiconductor switching assembly includes a plurality of semiconductor switches and a plurality of arresters in parallel to the semiconductor switches, the method comprising:
-
switching off the semiconductor switching assembly to reduce current in the circuit breaker to a residual current; and switching off the residual current by means of the mechanical switch, wherein; the arresters have an added threshold voltage exceeding the nominal voltage; the mechanical switch is arranged in a resonant circuit configured to generate an oscillating current through an arc in the mechanical switch after switching off the semiconductor switching assembly and opening the mechanical switch; the oscillating current has an amplitude exceeding the residual current such that at least one current zero crossing can be generated in the arc of the mechanical switch; and the method comprises extinguishing the arc during the current zero crossing. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method for switching off a high-voltage DC current from a voltage source delivering a nominal voltage by means of a circuit breaker including a semiconductor switching assembly and at least one mechanical switch in series, wherein the semiconductor switching assembly includes a plurality of semiconductor switches and a plurality of arresters in parallel to the semiconductor switches, the method comprising:
-
switching off the semiconductor switching assembly to reduce current in the circuit breaker to a residual current; and switching off the residual current by means of the mechanical switch, wherein; the arresters have an added threshold voltage exceeding the nominal voltage; and the residual current is below 20 Ampere. - View Dependent Claims (7, 8, 9)
-
-
10. A circuit breaker for switching off high-voltage DC currents of a nominal voltage, the circuit breaker comprising:
-
a semiconductor switching assembly including a plurality of semiconductor switches and a plurality of arresters in parallel to the semiconductor switches, the arresters having an added threshold voltage exceeding the nominal voltage; a mechanical switch arranged in series with the semiconductor switching assembly; and a resonant circuit including a capacitor and an arc gap of the mechanical switch, the capacitor being arranged in parallel to the mechanical switch, wherein; the circuit breaker is configured to switch off the semiconductor switching assembly to reduce current in the circuit breaker to a residual current, and switch off the residual current by opening the mechanical switch; the mechanical switch is arranged in the resonant circuit which is configured to generate an oscillating current through an arc in the mechanical switch after the semiconductor switching assembly is switched off and the mechanical switch is opened; the oscillating current has an amplitude exceeding the residual current such that at least one current zero crossing can be generated in the arc of the mechanical switch; and the arc is extinguished during the current zero crossing. - View Dependent Claims (11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
-
-
12. The circuit breaker of 10, wherein the capacitor has a capacitance in a range of 1 nF to 4 nF.
Specification