Method for fault current limiting between solid-state circuit breakers
A circuit breaker network includes a solid-state circuit breaker (SSCB), one or more circuit breakers, and a current limiting control circuit of the SSCB. The current limiting control circuit is programmed to determine a first time period for keeping the SSCB in an on state, determine a second time period for keeping the SSCB in an off state, and switch, cyclically, the SSCB to the off state for the second time period and then to the on state for the first time period to control the fault current within a predetermined band-to-band range that is below the first current threshold and above the second current threshold for a fault clearance duration.
1 . A circuit breaker network for executing fault current limiting control, comprising:
a solid-state circuit breaker (SSCB) disposed as a main or upstream circuit breaker, the SSCB comprising a current limiting control circuit, a semiconductor switch, and a voltage clamping circuit; and
one or more circuit breakers disposed as branch or downstream circuit breakers, wherein the current limiting control circuit comprises a processor, a memory, and computer-readable logic code stored in the memory, that when executed by the processor, causes the current limiting control circuit to:
determine a first time period for keeping the SSCB in an on state based at least in part on a delay time period for changing a state of the SSCB to the on state and a first current threshold associated with a tripping current threshold for the SSCB;
determine a second time period for keeping the SSCB in an off state based at least in part on a delay time period for changing the state of the SSCB to the off state, a second current threshold associated with a tripping current threshold for a circuit breaker of the one or more circuit breakers, and parameters of the voltage clamping circuit; and
switch, cyclically, the SSCB to the off state for the second time period and then to the on state for the first time period to control a fault current within a predetermined band-to-band range that is below the first current threshold and above the second current threshold for a fault clearance duration.
2 . The circuit breaker network according to claim 1 , wherein the circuit breaker is another SSCB or an electromechanical circuit breaker.
3 . The circuit breaker network according to claim 1 , wherein the SSCB further comprises a gate driver circuit configured to switch the SSCB between the on state and the off state.
4 . The circuit breaker network according to claim 3 , wherein the delay time period for changing a state of the SSCB to the on state and the delay time period for changing the state of the SSCB to the off state are based at least in part on a speed of opening and closing associated with the gate driver circuit.
5 . The circuit breaker network according to claim 1 , wherein the SSCB is arranged in a hierarchical manner such that the main or upstream circuit breaker feeds current to the branch or downstream circuit breaker, wherein the branch or downstream circuit breaker feeds the current to either end loads or to further smaller branch circuit breakers, wherein when a fault occurs only a closest circuit breaker of the one or more circuit breakers upstream of the fault will trip thereby enabling a load to continue to be provided to other circuit breakers of the one or more circuit breakers of the circuit breaker network.
6 . The circuit breaker network according to claim 1 , wherein the fault clearance duration corresponds to a certain time period required for the circuit breaker to clear a fault associated with the fault current.
7 . The circuit breaker network according to claim 6 , wherein the current limiting control circuit is further configured to switch the SSCB to the off state upon expiration of the fault clearance duration.
8 . The circuit breaker network according to claim 6 , wherein the current limiting control circuit is further configured to switch the SSCB to the on state in response to the circuit breaker clearing the fault.
9 . The circuit breaker network according to claim 1 , further comprising identifying that a fault is occurring in the circuit breaker network based at least in part on comparing the fault current to the second threshold.
10 . The circuit breaker network according to claim 1 , wherein determining the first time period, the second time period, and switching the SSCB is based on a user preference setting indicating the fault current limiting control for the SSCB.
11 . The circuit breaker network according to claim 1 , wherein a rate of rise for the fault current of a fault occurring in the circuit breaker network is based on a fault inductance between a source for the circuit breaker network and a fault location of the fault in the circuit breaker network.
12 . The circuit breaker network according to claim 1 , wherein switching the SSCB to the on state for the first time period allows the fault current for a fault to peak at a certain current value that falls in a first band.
13 . The circuit breaker network according to claim 12 , wherein switching the SSCB to the off state for the second time period allows the fault current for the fault to fall to another current value that falls in a second band.
14 . The circuit breaker network according to claim 13 , wherein the first band is less than the tripping current threshold for the SSCB, and wherein the second band is greater than the tripping current threshold for the circuit breaker.
15 . The circuit breaker network according to claim 1 , further comprising a direct current (DC) capacitor as a downstream load, and wherein the current limiting control circuit is further configured to switch, cyclically, the SSCB between the off state and the on state to charge the DC capacitor.
16 . The circuit breaker distribution system according to claim 15 , wherein a rate of rise of the current for charging the DC capacitor changes as the DC capacitor voltage increases.
17 . A method of providing fault current limiting control in a circuit breaker network, the method comprising:
providing a solid-state circuit breaker (SSCB) disposed as main or upstream circuit breaker, the SSCB comprising a current limiting control circuit, a semiconductor switch, and a voltage clamping circuit; and
a circuit breaker disposed as a branch of downstream breaker, wherein the current limiting control circuit is configured to:
determine a rate of rise for a fault current of a fault occurring in the circuit breaker network;
determine a first time period for keeping the SSCB in an on state based at least in part on the rate of rise for the fault current, a delay time period for changing a state of the SSCB to the on state, and a first current threshold associated with a tripping current threshold for the SSCB;
determine a second time period for keeping the SSCB in an off state based at least in part on a rate of fall for the fault current, a delay time period for changing the state of the SSCB to the off state, a second current threshold associated with a tripping current threshold for the circuit breaker, and parameters of the voltage clamping circuit; and
switch, cyclically, the SSCB to the off state for the second time period and then to the on state for the first time period to control the fault current within a predetermined band-to-band range that is below the first current threshold and above the second current threshold for a fault clearance duration.
18 . A current limiting control circuit of a solid-state circuit breaker (SSCB) for providing fault current limiting control in a circuit breaker network, the current limiting control circuit comprising processing circuitry configured to:
determine a rate of rise for a fault current of a fault occurring in the circuit breaker network;
determine a first time period for keeping the SSCB in an on state based at least in part on the rate of rise for the fault current, a delay time period for changing a state of the SSCB to the on state, and a first current threshold associated with a tripping current threshold for the SSCB;
determine a second time period for keeping the SSCB in an off state based at least in part on a rate of fall for the fault current, a delay time period for changing the state of the SSCB to the off state, and a second current threshold associated with a tripping current threshold for a circuit breaker of the circuit breaker network; and
switch, cyclically, the SSCB to the off state for the second time period and then to the on state for the first time period to control the fault current within a predetermined band-to-band range that is below the first current threshold and above the second current threshold for a fault clearance duration.
19 . The current limiting control circuit according to claim 18 , wherein the SSCB is disposed as a main or upstream circuit breaker, the circuit breaker is disposed as a branch or downstream circuit breaker, and wherein the SSCB is arranged in a hierarchical manner such that the main or upstream circuit breaker feeds the current to the branch or downstream circuit breaker, wherein the branch or downstream circuit breaker feeds the current to either end loads or to further smaller branch circuit breakers, wherein when the fault occurs only a closest circuit breaker of the one or more circuit breakers upstream of the fault will trip thereby enabling a load to continue to be provided to other circuit breakers of the one or more circuit breakers of the circuit breaker network.
20 . The current limiting control circuit according to claim 18 , wherein the fault clearance duration corresponds to a certain time period required for the circuit breaker to clear the fault.