DC CIRCUIT BREAKER
Provided is a DC circuit breaker capable of interrupting a failure current in both directions which flows in a DC transmission line when a failure occurs in the DC transmission line. The DC circuit breaker includes: a first mechanical switch connected to a first DC transmission line at a first side thereof, and connected to a first conductive connecting member at a second side thereof; a second mechanical switch connected to the first conductive connecting member at a first side thereof, and connected to a second DC transmission line at a second side thereof; a first diode connected to the first mechanical switch in parallel; a second diode serially connected to the first diode through the second conductive connecting member, and connected to the second mechanical switch 120 in parallel; and a semiconductor switching circuit switching a flow of a failure current when a failure occurs.
1 . A DC circuit breaker, comprising:
a first mechanical switch ( 110 ) connected to a first DC transmission line (DCL 1 ) at a first side thereof, and connected to a first conductive connecting member (SCL 1 ) at a second side thereof;
a second mechanical switch ( 120 ) connected to the first conductive connecting member (SCL 1 ) at a first side thereof, and connected to a second DC transmission line (DCL 2 ) at a second side thereof;
a first diode ( 130 ) connected to the first mechanical switch ( 110 ) in parallel by being connected to a first branch line (DL 1 ) branched from the first DC transmission line (DCL 1 );
a second diode ( 140 ) serially connected to the first diode ( 130 ) through the second conductive connecting member (SCL 2 ), and connected to the second mechanical switch ( 120 ) in parallel by being connected to a second branch line (DL 2 ) branched from the second DC transmission line (SCL 2 ); and
a semiconductor switching circuit ( 150 ) switching a flow of a failure current when a failure occurs by being installed in a transmission line (CL) between the first conductive connecting member (SCL 1 ) and the second conductive connecting member (SCL 2 ).
2 . The DC circuit breaker of claim 1 , wherein in the semiconductor switching circuit ( 150 ), at least one semiconductor switch ( 151 ) is serially connected in the same direction.
3 . The DC circuit breaker of claim 2 , wherein in the semiconductor switching circuit ( 150 ), a non-linear resistor ( 152 ) is connected to each semiconductor switch ( 151 ) in parallel.
4 . The DC circuit breaker of claim 3 , wherein a number of semiconductor switches ( 151 ) is proportional to a size of a voltage across both sides of the first DC transmission line (DCL 1 ) and the second DC transmission line (DCL 2 ).
5 . The DC circuit breaker of claim 3 , wherein the first diode ( 130 ) is connected to the first branch line (DL 1 ) at a cathode (K) thereof, and connected to the second conductive connecting member (SCL 2 ) at an anode (A) thereof, and the second diode 140 is connected to the second branch line (DL 2 ) at a cathode (K) thereof, and connected to the second conductive connecting member (SCL 2 ) at an anode (A) thereof.
6 . The DC circuit breaker of claim 3 , wherein the first and second mechanical switches ( 110 ) and ( 120 ) maintain close states during a normal operational state, and when a failure occurs in the first DC transmission line (DCL 1 ), the first mechanical switch ( 110 ) is opened and the semiconductor switch ( 151 ) is turned ON so that a failure current is conducted through the second mechanical switch ( 120 ), the semiconductor switch ( 151 ), and the first diode ( 130 ).
7 . The DC circuit breaker of claim 6 , wherein the semiconductor switch ( 151 ) is turned OFF after a preset time elapses after the failure current is conducted so that the failure current is provided to the non-linear resistor ( 152 ).
8 . The DC circuit breaker of claim 3 , wherein the first and second mechanical switches ( 110 ) and ( 120 ) maintain close states during a normal state, and when a failure occurs in the second DC transmission line (DCL 1 ), the second mechanical switch ( 120 ) is opened and the semiconductor switch 151 is turned ON so that a failure current is conducted through the first mechanical switch ( 110 ), the semiconductor switch ( 151 ), and the second diode ( 140 ).
9 . The DC circuit breaker of claim 8 , wherein the semiconductor switch ( 151 ) is turned OFF after a preset time elapses after the failure current is conducted so that the failure current is provided to the non-linear resistor ( 152 ).