Fault current limiter circuit breaker

Abstract

This disclosure relates to a method of operating a fault current limiter circuit breaker (FLCB) (1), the FLCB (1) comprising a plurality of FLCB modules (2) connected in series, including at least a first module (2a) and a second module (2b). Each module includes a plurality of parallel component branches, the plurality of parallel component branches including: a mechanical switch branch (3) including a mechanical switch (3a); a semiconductor switch branch (4) including a semiconductor switch (4a; 4b); and a metal oxide varistor (MOV) branch (5) including an MOV (5a). The method includes: obtaining an indication that the FLCB should be closed when the FLCB is in an open configuration; closing the semiconductor switch of each module in response to the obtained indication; and closing the mechanical switch of the first module after the semiconductor switch is closed and while the mechanical switch of the second module remains open.

Description

Technical Field

[0001] This disclosure relates to a fault current limiter circuit breaker (FLCB) and a method of operating the FLCB. Background Technology

[0002] FLCBs can be used in power systems where additional generators are installed, causing short-circuit currents in the system to exceed the ratings of the existing system. Without upgrading the entire system, FLCBs can be installed to limit peak currents within rated limits. One such solution is a hybrid FLCB, where the rapid switching of power semiconductors is combined with the low conduction losses of mechanical switches. The mechanical switches carry the nominal current with low losses, and in the event of a fault, the mechanical switches open and divert current to the parallel-connected semiconductors. The semiconductors then carry the rising fault current for a short period to allow the mechanical switches to open completely to prevent arcing. When the semiconductors are turned off, the mechanical switches must withstand transient overvoltages during the period when the current is forced to zero.

[0003] Furthermore, the closing sequence of a hybrid circuit breaker is also performed step-by-step. First, the semiconductor is turned on, allowing current to flow. If a system fault occurs, the current will rise rapidly, and the FLCB will trip again. The current can then be immediately interrupted because the mechanical switch remains open. If the system is not faulty, the mechanical switch should close because the semiconductor can only carry the nominal system current for about one second without overheating.

[0004] Problems arise if a fault occurs during the mechanical switch's closure. Because the mechanical switch is not in the closed position, it cannot be opened to divert current to the semiconductor. Once the mechanical switch is closed, it takes tens of milliseconds to open and interrupt the current. During this time, the system fault current will reach its full intended current, and the FLCB will be unable to function. Therefore, there is no guarantee that the FLCB will always perform its function correctly. Summary of the Invention

[0005] The purpose of this invention is to improve the reliability of hybrid FLCBs.

[0006] According to one aspect of the invention, a method for operating a fault current limiter circuit breaker (FLCB) is provided, the FLCB comprising a plurality of FLCB modules connected in series, including at least a first module and a second module. Each module includes a plurality of parallel component branches, the plurality of parallel component branches including: a mechanical switch branch including a mechanical switch; a semiconductor switch branch including a semiconductor switch; and a metal oxide varistor (MOV) branch including an MOV. The method includes: obtaining an indication that the FLCB should be closed when the FLCB is in an open configuration; closing the semiconductor switch of each module in response to the obtained indication; and closing the mechanical switch of the first module after the semiconductor switch is closed and while the mechanical switch of the second module remains open.

[0007] According to another aspect of the present invention, a computer program product is provided, including a computer executable component, such that a controller performs an embodiment of the method of the present disclosure when the computer executable component is running on a processing circuitry system included in the controller.

[0008] According to another aspect of the invention, an FLCB is provided, comprising a plurality of FLCB modules connected in series. The series-connected modules include at least a first module and a second module. Each module includes a plurality of parallel component branches, the plurality of parallel component branches including: a mechanical switch branch including a mechanical switch; a semiconductor switch branch including a semiconductor switch; an MOV branch including an MOV; and a controller including a processing circuit system and a data storage device storing instructions executable by the processing circuit system, whereby the controller is operable to obtain an indication that the FLCB should be closed when the FLCB is in an open configuration. The controller is also operable to close the semiconductor switch of each module in response to the obtained indication. The controller is also operable to close the mechanical switch of the first module when the semiconductor switch is closed and the mechanical switches of the second module are disconnected from each other. The FLCB can therefore be configured to perform embodiments of the methods disclosed herein.

[0009] According to another aspect of the present invention, a power distribution network is provided, including an embodiment of the FLCB disclosed herein.

[0010] By sequentially closing mechanical switches, where the mechanical switch of the second module remains open while the mechanical switch of the first module is closed, the sequential closing according to the invention enables the operation of the FLCB to limit fault current even when a fault is detected during FLCB closure, since mechanical switch closure takes several milliseconds (ms), i.e., the switching duration of the mechanical switch, and the mechanical switch may not be able to open again for another duration of tens of milliseconds (e.g., up to 100 ms) after closing, the operation of the FLCB can limit fault current even when a fault is detected during FLCB closure. Semiconductor switches can close or open the FLCB very quickly, but may only be able to carry current for a limited time, e.g., a rated current of up to 1A, without overheating, and are also used in the closing configuration to prevent arcing when the mechanical switch is opened. When both the mechanical switch and the semiconductor switch of the module are open, the fault current is directed to the MOV of the module, thereby reducing the voltage and absorbing the energy of the fault current.

[0011] It should be noted that any feature of any aspect can be applied to any other aspect, as appropriate. Similarly, any advantage of any aspect can be applied to any other aspect. Other objects, features, and advantages of the accompanying embodiments will become apparent from the following detailed disclosure, the appended dependent claims, and the drawings.

[0012] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. Unless otherwise expressly stated, all references to “element, device, component, part, step, etc.” are to be interpreted as referring to at least one instance of an element, device, component, part, step, etc. Unless expressly stated otherwise, the steps of any method disclosed herein need not be performed in the exact order disclosed. The use of “first,” “second,” etc., for different features / components of this disclosure is intended only to distinguish features / components from other similar features / components, and not to assign any order or hierarchy to the features / components. Attached Figure Description

[0013] The embodiments will be described by way of example only with reference to the accompanying drawings, wherein:

[0014] Figure 1 This is a schematic circuit diagram of an FLCB connected in a power distribution network according to some embodiments of the present invention.

[0015] Figure 2 This is a schematic block diagram of an embodiment of the controller of an FLBC according to some embodiments of the present invention.

[0016] Figure 3 This is a schematic flowchart illustrating some embodiments of the method of the present invention.

[0017] Figure 4These are schematic flowcharts illustrating some embodiments of alternative methods of the present invention. Detailed Implementation

[0018] Embodiments will now be described more fully below with reference to the accompanying drawings, in which particular embodiments are shown. However, many other embodiments of different forms are possible within the scope of this disclosure. Rather, the following embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. The same numerals refer to the same elements throughout the description.

[0019] In this article, the term "open" is used for non-conductive switches (whether mechanical or semiconductor) (corresponding to a semiconductor switch that is turned off), while the term "closed" is used for conductive switches (corresponding to a semiconductor switch that is turned on).

[0020] Figure 1 The illustration shows an FLBC 1 comprising multiple modules 2 connected in series with each other. FLBC 1 includes at least a first series-connected module 2a and a second series-connected module 2b, for example, ranging from two to ten modules, such as the four modules 2a, 2b, 2c, and 2d in the embodiment shown in the figures. As discussed herein, the first module 2a and the second module 2b can be any adjacent (i.e., directly connected to each other without any other modules in between) modules in the multiple series-connected modules. The FLBC is capable of interrupting and absorbing / dissipating fault (e.g., short-circuit) currents, for example in a distribution network 10, to prevent currents from rising beyond the handling capacity of existing circuit breakers. This functionality allows for network expansion without upgrading equipment such as switchgear, cables, or transformers. In particular, recent demand for connecting renewable energy sources (such as solar and / or wind power) may result in high fault currents. FLBC 1 can be included in such a distribution network 10. The distribution network can be configured for nominal voltages in the medium voltage (MV) range, for example, a nominal voltage of at least 1 kV, such as in the 2 kV and 35 kV range.

[0021] Each module 2 includes multiple parallel component branches, including: a mechanical switch branch 3, including a mechanical switch 3a; a semiconductor switch branch 4, including a semiconductor switch 4a or 4b; and an MOV branch 5, including an MOV 5a. Optionally, the multiple parallel branches also include a buffer branch 6, which includes a buffer, such as an RC buffer including a resistor 6a and a capacitor 6b connected in series with each other.

[0022] The mechanical switch 3a of each module can be any suitable mechanical switch that can move to open and close the current connection in the mechanical switch branch 3. Preferably, the mechanical switch is or includes a Thomson switch, which is an example of a mechanical switch with a relatively short switching duration. A short switching duration of the mechanical switch (i.e., the time it takes for the mechanical switch to move from its open position to its closed position, and vice versa) is preferred to enable the FLBC to handle detected fault currents more quickly. The mechanical switch can, for example, have a switching duration in the range of 5 to 10 milliseconds (ms). Compared to semiconductor switches 4a or 4b, mechanical switches have the advantages of lower conduction losses and the ability to handle relatively large currents with respect to cost. The disadvantage of mechanical switches is that they are relatively slow, i.e., they have a relatively long switching duration compared to semiconductor switches.

[0023] Semiconductor switch branch 4 includes at least one semiconductor 4a or 4b, which is primarily configured to react faster than mechanical switch 3a during the opening or closing of the FLBC, but is typically only used to conduct current (fault or nominal current) for a limited period of time during the opening or closing of the mechanical switch. For example, the semiconductor switch may conduct current for at most 1 second (s) to avoid overheating. The semiconductor switch may have a relatively short switching duration, such as less than 20 microseconds (μs), for example in the range of 5 to 15 μs. Semiconductor switch 4a or 4b is typically or includes an active turn-off semiconductor switch, such as an insulated-gate bipolar transistor (IGBT), a dual-mode insulated-gate transistor (BiGT), a gate turn-off thyristor (GTO), or an integrated gate commutated thyristor (IGCT), typically with an anti-parallel diode. In some embodiments, the BiGT is preferred. It may be advantageous for the FLBC and each of its modules 2 to be bidirectional, particularly for AC network applications, in which case two semiconductor switches 4a and 4b of different polarities connected in series with each other may be included in semiconductor switch branch 4, such as two BiGTs of different polarities as shown in the figures. In the case where semiconductor switch branch 4 includes more than one semiconductor switch 4a and 4b, the opening or closing of the semiconductor switch as discussed herein means that the associated semiconductor switch (e.g., depending on the polarity of the current) used to control the conductivity of semiconductor switch branch 4 is open or closed (or is opening or closing).

[0024] MOV 5a is arranged to consume (also known as absorb) the electrical energy of fault current when the current is directed through the MOV of the module, since both the mechanical and semiconductor switches of the module are disconnected.

[0025] FLBC 1 may also include a controller for controlling the operation of the FLBC, particularly the opening and closing of the mechanical switch 3a and the semiconductor switches 4a and 4b of module 2, for example, to enable the FLBC to perform the methods of this disclosure.

[0026] Figure 2 The diagram illustrates a controller 9. The controller 9 includes a processing circuitry system 91, such as a central processing unit (CPU). The processing circuitry system 91 may include one or more processing units in the form of microprocessors(s). However, other suitable devices with computing capabilities may be included in the processing circuitry system 91, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or complex programmable logic devices (CPLDs). The processing circuitry system 91 is configured to run one or more computer programs or software(SW)(s)93, which are stored in a storage device 92 of one or more storage units, such as a memory. The storage units are considered computer-readable components 92, forming a computer program product, as discussed herein, together with the SW 93 stored thereon as computer-executable components, and may be, for example, in the form of random access memory (RAM), flash memory or other solid-state memory or a hard disk, or a combination thereof. The processing circuitry system 91 may also be configured to store data in the storage device 92 as needed.

[0027] Figure 3 Some embodiments of the method of operating FLCB 1 according to the present invention are illustrated.

[0028] When the FLBC is in the off configuration, i.e., when the mechanical switch 3a and semiconductor switch 4a or 4b of each module 2 in module 2 are off, an indication is obtained S1 that the FLBC should be closed (i.e., conducted via each module in its module). In response to the indication of obtaining S1, the semiconductor switch 4a or 4b of each module 2 in module 2 is typically closed simultaneously S2. After the closing of semiconductor switch 4a or 4b S2, the mechanical switch 3a of the first module 2a is closed S3 while the mechanical switch 3a of the second module 2b remains off. As discussed herein, the switching duration of the mechanical switches is relatively long, for example in the range of 5 to 10 ms, allowing the semiconductor switches to switch again (if necessary) when the mechanical switch 3a of the first module 2a is closed S3.

[0029] In some embodiments of the invention, option a), for example, when no fault current is detected during the FLCB closure, after the mechanical switch 3a of the first module 2a is closed (S3), i.e., after the mechanical switch of the first module has reached its closed position (conduction), the mechanical switch 3a of the second module 2b is closed (S4a). Then, when the mechanical switches of each of the plurality of modules have been closed (S3 and S4a, i.e., have reached their closed positions and are conducting), the corresponding semiconductor switch 4a or 4b of each module 2 in module 2 is opened (S5a). When the corresponding mechanical switch of each module in the module is in its closed position, the FLCB is closed and conducts via each corresponding mechanical switch of the series-connected modules. To avoid overheating of the semiconductor switches and reduce conduction losses, the semiconductor switch of each module in the module is opened when the FLCB is closed.

[0030] In some other embodiments of the invention, option b) detects or infers the fault current during the closure of the mechanical switch S3 of the first module (providing an indication that the FLCB should be reopened). Thus, the indication that FLCB 1 should be reopened is obtained S4b during the closure of the mechanical switch 3a of the first module 2a, while the mechanical switch 3a of the second module 2b remains open (not yet initiated for closing, as the mechanical switches are closed sequentially). In response to the acquisition of the indication that FLCB 1 should be reopened S4b, the semiconductor switch 4a or 4b of the second module 2b is opened S5b, forcing the fault current through the MOV 5a of the second module 2b. Then, after the semiconductor switch 4a or 4b of the second module 2b is opened S5b, the mechanical switch 3a of the first module 2a is opened. Typically, the mechanical switch of the first module completes its closure S3 (conduction) before it is opened S6b. During the closure of the mechanical switch of the first module S3, the semiconductor switch of the first module can remain closed to avoid arcing at the mechanical switch. After the mechanical switch of the first module has been fully opened to avoid arcing, the semiconductor switch 4a or 4b of the first module 2a can also be opened. Therefore, if a fault current is detected during the closure of the mechanical switch of the first module, the current can be quickly disconnected in the second module by means of some embodiments of the present invention since the mechanical switch of the second module remains open, and the semiconductor switch of the second module can be quickly opened S5b to direct the fault current to the MOV of the second module.

[0031] In some other embodiments of the invention, option c), during the closing of the mechanical switch of the second module S4c, a fault current is detected or inferred (providing an indication that the FLCB should be reopened), and the second module mechanical switch closes sequentially after the first module mechanical switch reaches its closed position in response to the indication of closing the FLCB S1. Thus, after the mechanical switch 3a of the first module 2a closes S3, the mechanical switch 3a of the second module 2b is closed S4c. Then, during the closing of the mechanical switch 3a of the second module 2b S4c, while the mechanical switch 3a of the first module 2a remains closed (it has been closed S3), an indication that the FLCB 1 should be reopened is obtained S5c, typically due to the detection of a fault current. In response to the obtaining of the indication that the FLCB 1 should be reopened S5c, the mechanical switch 3a of the first module 2a and the semiconductor switch 4a or 4b of the first module are reopened S6c, forcing the fault current through the MOV 5a of the first module 2b. Then, after the semiconductor switch 4a or 4b of the first module 2a is opened (S6c), and typically also after the mechanical switch 3a of the first module is opened (although alternatively, it may be opened during the opening of the mechanical switch of the first module), the mechanical switch 3a of the second module 2b is opened (S7c). After the mechanical switch of the second module has been sufficiently opened to avoid arcing, the semiconductor switch 4a or 4b of the second module 2a may also be opened. Therefore, if a fault current is detected during the closing of the mechanical switch of the second module, the current can, in any case, be quickly disconnected in the first module after the mechanical switch of the first module is closed, by some embodiments of the invention, because the mechanical switch of the first module is in its closed position and can be reopened (S6c), and the semiconductor switch of the first module can also be quickly opened, directing the fault current to the MOV of the first module.

[0032] In some embodiments of the invention, during the closing of mechanical switch 3a (S3 or S4c) and after obtaining the indication that the FLBC should be disconnected (S4b or S5c), the semiconductor switch 4a or 4b of the same module as the mechanical switch closing (S3 or S4c) may also be disconnected, forcing fault current through the MOV 5a of that module until the mechanical switch is closed (i.e., providing current connection). To avoid arcing when the mechanical switch reaches its closed position, the semiconductor switch can then be reclosed during the closing of the mechanical switch (S3 or S4c), typically just before the mechanical switch reaches its closed position and thus provides current connection. Since the switching time of the semiconductor switch is much faster than that of the mechanical switch, the semiconductor switch can be disconnected immediately after the indication to disconnect the FLBC is obtained, to further dissipate the fault current by forcing it through another MOV during the mechanical switch closing but before it reaches its closed position. Disconnecting the semiconductor switch in the module during the closing of the mechanical switch in the FLBC may be particularly useful when the mechanical switch is last closed in the FLBC.

[0033] Figure 4 The illustration depicts a semiconductor switch being opened (and optionally re-closed) during the closure of the mechanical switch of a module. The FLCB can then consist, for example, of only one module 2, or include multiple modules that are operated simultaneously (especially where the mechanical switch of each module is simultaneously closed and opened), rather than based on... Figure 3 The operation proceeds sequentially. An indication that FLCB 1 should be closed is received A1. In response to the receipt of indication A1, semiconductor switches 4a and / or 4b are closed A2. Furthermore, mechanical switch 3a closes A3 in response to the receipt of indication A1, but during the closure of mechanical switch A3, an indication to open FLCB is received A4. In response to the receipt of indication A4, the semiconductor switch is opened A5 during the closure of mechanical switch A3, thereby forcing fault current through MOV 5a before the mechanical switch reaches its closed position and providing current connection. Optionally, to avoid arcing at the mechanical switch, the semiconductor switch can be reclosed before the mechanical switch reaches its closed position, providing current connection. Because mechanical switches have a much longer switching duration than semiconductor switches—that is, the time it takes for a mechanical switch to close from its open position to its closed position (where current connection is provided)—a semiconductor switch can open A5 while the mechanical switch is closed (i.e., during the switching time) and may reclose A6. This greatly contributes to the handling of fault current, as the fault current is directed through MOV 5a and thus consumed through MOV 5a during this time period (after the semiconductor switch opens A5, but before the mechanical switch reaches its closed position).

[0034] Then, after the mechanical switch has reached its closed position, it can be reopened A7. If the semiconductor switch has already reopened A6, it can reopen A8 during the reopening of the mechanical switch A7 to avoid arcing during the reopening of the mechanical switch A7. Therefore, if the semiconductor switch A6 is reopened just before the mechanical switch reaches its closed position during its closing A3, the semiconductor switch is closed to avoid arcing at the end of the closing A3 and reopening A7 of the mechanical switch.

[0035] Therefore, in some embodiments, during the closing of the mechanical switch 3a of the first module 2a in S3, in response to an indication that FLCB 1 should be disconnected in S4b, the method further includes disconnecting the semiconductor switch 4a or 4b of the first module A5. In some embodiments, the method then further includes reclosing the semiconductor switch 4a or 4b of the first module A6 during the closing of the mechanical switch of the first module in S3.

[0036] In some other embodiments, during the closing of the mechanical switch 3a of the second module 2b in S4c, in response to an indication that FLCB 1 should be disconnected in S5c, the method further includes disconnecting the semiconductor switch 4a or 4b of the second module A5. In some embodiments, the method then further includes reclosing the semiconductor switch 4a or 4b of the second module A6 during the closing of the mechanical switch of the second module in S4c.

[0037] It should be noted that when the FLBC has only one module, or when the FLBC has multiple modules connected in series but these modules are not configured to close the mechanical switch sequentially as discussed herein, it may also be advantageous to open the semiconductor switch of the same module that is in the closing process of the mechanical switch.

[0038] Therefore, according to an alternative aspect of the invention, a method for operating a fault current limiter circuit breaker (FLCB) 1 is provided, the FLCB 1 including an FLCB module 2. The module includes a plurality of parallel component branches, including: a mechanical switch branch 3, including a mechanical switch 3a; a semiconductor switch branch 4, including a semiconductor switch 4a or 4b; and a metal oxide varistor (MOV) branch 5, including an MOV 5a. The method includes: obtaining an indication A1 that the FLCB should be closed when the FLCB is in an open configuration. The method further includes: closing the semiconductor switch 4a or 4b A2 in response to obtaining the indication A1. The method further includes: closing the mechanical switch 3a A3 after the semiconductor switch A2 is closed. The method further includes: obtaining an indication A4 that the FLCB 1 should be open during the closure of the mechanical switch 3a A3. The method further includes: in response to an indication that FLCB 1 should be disconnected, during the closure of mechanical switch 3a (A3), disconnecting semiconductor switch 4a or 4b (A5) to force fault current through MOV 5a. The method also includes: after the closure of mechanical switch 3a (A3), re-disconnecting mechanical switch 3a (A7).

[0039] In some embodiments of alternative aspects of the invention, the method further includes: re-disconnecting semiconductor switch 4a or 4b A6 during the closing of mechanical switch 3a A3 after semiconductor switch 4a or 4b is disconnected A5. In some embodiments, the method further includes: re-disconnecting semiconductor switch 4a or 4b A8 during the re-disconnection of mechanical switch 3a A7.

[0040] In some embodiments of the invention, each of the mechanical switches 3a includes a Thomson switch. A Thomson switch is an example of a relative pair of mechanical switches that can be adapted to the mechanical switches 3a.

[0041] In some embodiments of the invention, each of the semiconductor switches 4a and / or 4b includes an active turn-off semiconductor switch, such as an insulated gate bipolar transistor (IGBT), a dual-mode insulated gate transistor (BiGT), a gate turn-off thyristor (GTO), or an integrated gate commutated thyristor (IGCT), such as the BiGT that may be preferred in some embodiments illustrated herein.

[0042] In some embodiments of the present invention, the corresponding semiconductor switch branch 4 of each module 2 includes bidirectional semiconductor switch arrangements 4a and 4b, for example, including two BiGTs connected in series but with different polarities, such as... Figure 1 As illustrated, a bidirectional semiconductor switch arrangement may be required for AC applications, while some DC applications may operate using a unidirectional semiconductor switch arrangement, such as one consisting of a single BiGT.

[0043] In some embodiments of the present invention, each mechanical switch 3a in the mechanical switch 3a has a switching duration in the range of 5 to 10 ms.

[0044] In some embodiments of the present invention, each of the semiconductor switches (4a, 4b) has a switching duration in the range of 5 to 15 μs.

[0045] In some embodiments of the invention, multiple parallel component branches include a buffer branch 6, which includes a resistor 6a and a capacitor 6b connected in series, thereby providing a conventional RC buffer circuit.

[0046] Embodiments of the present invention can be readily implemented using one or more conventional general-purpose or special-purpose digital computers, computing devices, machines, or microprocessors, including one or more processors, memory, and / or computer-readable storage media programmed according to the teachings of this disclosure. Appropriate software code can be readily prepared by skilled programmers based on the teachings of this disclosure, as will be apparent to those skilled in the art of software.

[0047] In some embodiments, the present invention includes a computer program product, which is a non-transient storage medium or computer-readable medium (medium) 92, on which / therein are stored instructions 93 in the form of computer-executable components or software (SW), which can be used to program a computer 9 to perform any method / process of the present invention. Examples of storage medium 92 may include, but are not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0048] This disclosure has been described above primarily with reference to several embodiments. However, as will be readily apparent to those skilled in the art, other embodiments besides those disclosed above are also possible within the scope of this disclosure as defined by the appended claims.

Claims

1. A method for operating a fault current limiter circuit breaker (FLCB) (1), the fault current limiter circuit breaker (FLCB) (1) comprising a plurality of FLCB modules (2) connected in series, including at least a first module (2a) and a second module (2b), each module comprising a plurality of parallel component branches, the plurality of parallel component branches comprising: Mechanical switch branch (3), including mechanical switch (3a); Semiconductor switch branch (4), including semiconductor switch (4a); 4b)； as well as Metal oxide varistor MOV branch (5), including MOV (5a); The method includes: When the FLBC is in the disconnected configuration, an indication is obtained (S1) that the FLBC should be closed; In response to the received (S1) instruction, the semiconductor switches (4a; 4b) of each module (2) in the module (2) are closed (S2); and After the semiconductor switches (4a; 4b) are closed (S2), and while the mechanical switch (3a) of the second module (2b) remains open, the mechanical switch (3a) of the first module (2a) is closed (S3).

2. The method according to claim 1, further comprising: After the mechanical switch (3a) of the first module (2a) is closed (S3), the mechanical switch (3a) of the second module (2b) is closed (S4a); as well as When the mechanical switch of each of the plurality of modules has been closed (S3; S4a), the semiconductor switch of each of the modules (2) is opened (S5a) (4a; 4b).

3. The method according to claim 1, further comprising: During the closure (S3) of the mechanical switch (3a) of the first module (2a), while the mechanical switch (3a) of the second module (2b) remains open, an indication is obtained (S4b) that the FLCB (1) should be disconnected; In response to the indication that the FLCB (1) should be disconnected (S4b), the semiconductor switch (4a; 4b) of the second module (2b) is disconnected (S5b), forcing the fault current through the MOV (5a) of the second module (2b); and After the semiconductor switch (4a; 4b) of the second module (2b) is disconnected (S5b), the mechanical switch (3a) of the first module (2a) and the semiconductor switch (4a; 4b) of the first module (2a) are disconnected (S6b).

4. The method according to claim 3, further comprising: During the closure (S3) of the mechanical switch (3a) of the first module (2a), in response to the acquisition (S4b) of the indication that the FLCB 1 should be disconnected, the semiconductor switch (4a; 4b) of the first module is disconnected (A5); as well as During the closing (S3) of the mechanical switch (3a) of the first module (2a), the semiconductor switch (4a; 4b) of the first module is reclosed (A6).

5. The method according to claim 1, further comprising: After the mechanical switch (3a) of the first module (2a) is closed (S3), the mechanical switch (3a) of the second module (2b) is closed (S4c); During the closure (S4c) of the mechanical switch (3a) of the second module (2b), while the mechanical switch (3a) of the first module (2a) remains closed, an indication is obtained (S5c) that the FLCB (1) should be disconnected; In response to the indication that the FLCB (1) should be disconnected, the mechanical switch (3a) of the first module (2a) and the semiconductor switch (4a; 4b) of the first module (2a) are disconnected (S6c), and the fault current is forced through the MOV (5a) of the first module (2b). as well as After the semiconductor switches (4a; 4b) of the first module (2a) are disconnected (S6c), the mechanical switch (3a) of the second module (2b) and the semiconductor switches (4a; 4b) of the second module (2b) are disconnected (S7c).

6. The method according to claim 5, further comprising: During the closing (S4c) of the mechanical switch (3a) of the second module (2b), in response to the indication that the FLCB (1) should be disconnected (S5c), the semiconductor switch (4a; 4b) of the second module is disconnected (A5); as well as During the closing (S4c) of the mechanical switch (3a) of the second module (2b), the semiconductor switch (4a; 4b) of the second module is reclosed (A6).

7. The method according to any one of the preceding claims, wherein each of the mechanical switches (3a) comprises a Thomson switch.

8. The method according to any one of claims 1 to 6, wherein each of the semiconductor switches (4a; 4b) comprises an active turn-off semiconductor switch.

9. The method according to any one of claims 1 to 6, wherein each of the semiconductor switch branches (4) comprises a bidirectional semiconductor switch arrangement (4a; 4b).

10. The method according to any one of claims 1 to 6, wherein each of the mechanical switches (3a) has a switching duration in the range of 5 to 10 ms.

11. The method according to any one of claims 1 to 6, wherein each of the semiconductor switches (4a; 4b) has a switching duration in the range of 5 to 15 μs.

12. The method according to any one of claims 1 to 6, wherein the plurality of parallel component branches include a buffer branch (6), the buffer branch (6) including a resistor (6a) and a capacitor (6b) connected in series.

13. The method according to claim 8, wherein the active turn-off semiconductor switch is an insulated gate bipolar transistor (IGBT), a dual-mode insulated gate transistor (BiGT), a gate turn-off thyristor (GTO), or an integrated gate commutation thyristor (IGCT).

14. The method of claim 9, wherein the bidirectional semiconductor switch arrangement (4a; 4b) comprises two BiGTs connected in series but having different polarities.

15. A computer program product (92) comprising a computer executable component (93) for causing a controller (9) to perform the method according to any one of the preceding claims when the computer executable component is run on a processing circuitry system (91) included in the controller.

16. A fault current limiter circuit breaker (FLCB) (1) comprising a plurality of FLCB modules (2) connected in series, the plurality of FLCB modules (2) comprising at least a first module (2a) and a second module (2b), each module comprising a plurality of parallel component branches, the plurality of parallel component branches comprising: Mechanical switch branch (3), including mechanical switch (3a); Semiconductor switch branch (4), including semiconductor switch (4a); 4b)； Metal oxide varistor MOV branch (5), including MOV (5a); as well as The controller (9) includes a processing circuit system (91) and a data storage device (92) for storing instructions (93), which are executable by the processing circuit system, thereby enabling the controller to operate as follows: When the FLBC is in a disconnected configuration, an indication is obtained that the FLBC should be closed; In response to the received instruction, the semiconductor switches (4a; 4b) of each module (2) are closed; as well as When the semiconductor switch (4a; 4b) is closed and the mechanical switch (3a) of the second module (2b) remains open, the mechanical switch (3a) of the first module (2a) is closed.

17. A power distribution network (10) comprising the FLCB (1) according to claim 16.

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