WO2025182030A1 - Selective cooperation system for semiconductor circuit breaker - Google Patents

Abstract

A selective coordination system (100) for a semiconductor circuit breaker comprises: a semiconductor circuit breaker (1) that opens and closes an electric path (2) by means of a semiconductor module (12); a first current sensor (14) that measures a current flowing through the semiconductor circuit breaker (1); a plurality of switches (21-2N) that are connected to the load side of the semiconductor circuit breaker (1); a plurality of second current sensors (31-3N) that measure a current flowing through each of the plurality of switches (21-2N); and a control unit (16). The control unit (16), upon detection of a fault current by the first current sensor (14): causes the semiconductor module (12) to perform current limiting control; determines, on the basis of the currents measured by the plurality of second current sensors (31-3N), a switch through which the fault current has flowed, from among the plurality of switches (21-2N); and causes said switch to perform open operation after the current limiting control is performed. Each of the plurality of switches (21-2N) has opening/closing contacts or a semiconductor element.

Description

Semiconductor circuit breaker selection and coordination system

This disclosure relates to a semiconductor circuit breaker selective coordination system in which a semiconductor circuit breaker serves as the main circuit breaker and the branch side serves as a switch.

Conventionally, a selective circuit breaker has been known that includes a main circuit breaker, a current reduction means that temporarily reduces an overcurrent when an overcurrent flows due to an accident, and multiple branch circuit breakers installed on the branch side of the electrical circuit.The selective circuit breaker will trip a branch circuit breaker when an accident occurs on the secondary side of the branch circuit breaker, and will trip the branch circuit breaker if the overcurrent does not return to a set value or below within a predetermined time after the accident (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 5-15053

However, with conventional technology, the current-limiting performance of the main circuit breaker is low, so mechanical circuit breakers must also be installed in the branch circuit breakers, and these branch circuit breakers also need to have the breaking capacity to interrupt short-circuit currents. There is a demand for simple, inexpensive switchboard configurations.

The present disclosure was made in light of the above, and aims to provide a semiconductor circuit breaker selection and coordination system that allows for a simple and inexpensive configuration of distribution panels.

In order to solve the above-mentioned problems and achieve the objectives, the semiconductor circuit breaker selection and coordination system disclosed herein comprises a semiconductor circuit breaker that opens and closes an electric circuit using a semiconductor element, a first current sensor that measures the current flowing in the semiconductor circuit breaker, multiple switches connected to the load side of the semiconductor circuit breaker, multiple second current sensors that measure the current flowing in each of the multiple switches, and a control unit that causes the semiconductor element to perform current-limiting control when the first current sensor detects a fault current, determines from the multiple switches through which the fault current has flowed based on the currents measured by the multiple second current sensors, and causes the switch to open after the current-limiting control has been performed. Each of the multiple switches has an open/close contact or a semiconductor element.

The semiconductor circuit breaker selection and coordination system disclosed herein has the advantage of enabling the construction of a simple and inexpensive distribution panel.

FIG. 1 is a diagram showing a configuration of a semiconductor circuit breaker selection coordination system according to a first embodiment; FIG. 1 is a diagram showing a single-pole configuration of a semiconductor module in a semiconductor circuit breaker included in a semiconductor circuit breaker selection coordination system according to a first embodiment. 1 is a flowchart showing the procedure of an operation performed by a semiconductor circuit breaker included in a semiconductor circuit breaker selection coordination system according to a first embodiment. FIG. 1 is an explanatory diagram for explaining the operation of the semiconductor circuit breaker selective coordination system according to the first embodiment. FIG. 10 is a diagram showing the configuration of a semiconductor circuit breaker selective coordination system according to a second embodiment. 10 is a flowchart showing the procedure of an operation performed by a semiconductor circuit breaker included in a semiconductor circuit breaker selection coordination system according to a second embodiment. FIG. 10 is a diagram showing the configuration of a semiconductor circuit breaker selective coordination system according to a third embodiment. FIG. 8 is a diagram showing the state of the electric circuit when the semiconductor circuit breaker operates, in order to explain a method for estimating the current of each branch circuit shown in FIG. 7 from the electric wire specifications. 10 is a flowchart showing the procedure of an operation performed by a semiconductor circuit breaker included in a semiconductor circuit breaker selection coordination system according to a third embodiment. A flowchart showing the procedure of the operation of the inductance estimation process of the fault branch circuit in FIG. FIG. 10 is a diagram showing a current waveform when a semiconductor circuit breaker included in a semiconductor circuit breaker selective coordination system according to a third embodiment is performing a current limiting operation. FIG. 1 is a diagram showing a processor in a case where some or all of the functions of a current measurement unit and a control unit included in the semiconductor circuit breaker selective coordination system according to the first embodiment are realized by the processor. FIG. 1 is a diagram showing a processing circuit in the case where some or all of the functions of a current measurement unit and a control unit included in the semiconductor circuit breaker selective coordination system according to the first embodiment are realized by the processing circuit.

Below, a detailed description of the semiconductor circuit breaker selective coordination system according to an embodiment is provided with reference to the accompanying drawings.

Embodiment 1.
FIG. 1 is a diagram showing the configuration of a semiconductor circuit breaker selection coordination system 100 according to a first embodiment. The semiconductor circuit breaker selection coordination system 100 includes a semiconductor circuit breaker 1 that uses a semiconductor element to interrupt an electric circuit 2. The semiconductor element is a semiconductor module 12, which will be described later. The semiconductor circuit breaker selection coordination system 100 further includes a plurality of switches 21-2N and a plurality of second current sensors 31-3N connected in parallel to the load side of the semiconductor circuit breaker 1. The number of the plurality of second current sensors 31-3N is the same as the number of the plurality of switches 21-2N. Each of the plurality of second current sensors 31-3N is connected to a corresponding one of the plurality of switches 21-2N. For example, the second current sensor 31 is connected to the switch 21, and the second current sensor 3N is connected to the switch 2N.

Each of the multiple second current sensors 31-3N is connected to a corresponding load. Figure 1 shows multiple loads 41-4N. The number of multiple loads 41-4N is the same as the number of multiple second current sensors 31-3N. For example, load 41 is connected to second current sensor 31, and load 4N is connected to second current sensor 3N. Each of the multiple second current sensors 31-3N detects the current flowing through the corresponding load. For example, second current sensor 31 detects the current flowing through load 41, and second current sensor 3N detects the current flowing through load 4N.

The semiconductor circuit breaker 1 comprises a semiconductor module 12 that is provided on the electrical circuit 2 and turns the current flowing through the electrical circuit 2 on and off; a mechanical element 13 that is provided on the electrical circuit 2 in series with the semiconductor module 12 and opens and closes the electrical circuit 2; a first current sensor 14 that detects the current flowing through the electrical circuit 2; a current measurement unit 15 that receives the output signal of the first current sensor 14 and measures the current flowing through the electrical circuit 2; and a control unit 16 that controls the semiconductor module 12 and the mechanical element 13 based on the current value measured by the current measurement unit 15. The current values detected by each of the multiple second current sensors 31-3N are also input to the current measurement unit 15.

In embodiment 1, the semiconductor module 12 and mechanical element 13 are, for example, three-pole elements corresponding to three-phase AC. Figure 2 is a diagram showing the single-pole configuration of the semiconductor module 12 in the semiconductor circuit breaker 1 included in the semiconductor circuit breaker selection coordination system 100 according to embodiment 1. In other words, Figure 2 shows the single-pole structure of the semiconductor module 12 shown in Figure 1. The single-pole structure shown in Figure 2 is a structure that is responsible for energizing and blocking current for each phase. Each of the semiconductor module 12 and mechanical element 13 has three identical structures corresponding to the three power lines of the U phase, V phase, and W phase.

The single-pole structure of the semiconductor module 12 shown in Figure 2 includes two semiconductor elements 121. Each semiconductor element 121 is a semiconductor switching element. The on/off state of each semiconductor element 121 is controlled by a gate control signal s2 from the control unit 16. When the semiconductor element 121 is on, it energizes the electrical circuit connecting the power source and the load, and when the state of the semiconductor element 121 switches from on to off, it interrupts the current in the electrical circuit.

Semiconductor element 121 has unidirectional blocking capability. Semiconductor element 121 is, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). If semiconductor element 121 is a MOSFET, one terminal 122 of semiconductor element 121 is a drain terminal, and the other terminal 123 of semiconductor element 121 is a source terminal. If semiconductor element 121 is an IGBT, one terminal 122 is a collector terminal, and the other terminal 123 is an emitter terminal. Semiconductor element 121 can only block current of the polarity flowing from terminal 122 to terminal 123.

In order to give the semiconductor module 12 the bidirectional blocking capability of blocking both forward and reverse currents, in the semiconductor module 12, as shown in FIG. 2, two semiconductor elements 121 are connected in series with the terminal 122 of one semiconductor element 121 facing the terminal 122 of the other semiconductor element 121. Note that the two semiconductor elements 121 may also be connected in series with the terminal 123 of one semiconductor element 121 facing the terminal 123 of the other semiconductor element 121. The diode 124 is connected in parallel with the semiconductor element 121. The diode 124 bypasses currents in directions that the semiconductor element 121 cannot block.

Next, the operation of the semiconductor circuit breaker selection coordination system 100 will be described with reference to the flowchart in Figure 3. Figure 3 is a flowchart showing the procedure of the operation performed by the semiconductor circuit breaker 1 included in the semiconductor circuit breaker selection coordination system 100 according to the first embodiment. Figure 3 mainly shows the procedure of the operation performed by the control unit 16 included in the semiconductor circuit breaker 1. In step S101, the current measurement unit 15 measures the current value I _M detected by the first current sensor 14. In step S102, the current measurement unit 15 measures the current values I _SW1 to I _SWN detected by each of the second current sensors 31 to 3N.

In step S103, the control unit 16 determines whether the current value I 1 _M measured in step S101 by the first current sensor 14 is greater than a first threshold value. If the control unit 16 determines that the current value I 1 _M is greater than the first threshold value (Yes in S103), the operation proceeds to step S104. If the control unit 16 determines that the current value I _{1 M} is equal to or less than the first threshold value (No in S103), the operation proceeds to step S105.

In step S104, the control unit 16 immediately turns off the semiconductor module 12 and cuts off the current. This is an operation performed because it may be difficult to perform current limiting control in the semiconductor module 12, and cutting off the current may also be difficult. That is, in step S104, the control unit 16 immediately cuts off the current in the semiconductor module 12. In Figure 3, the operation of step S104 is indicated by the phrase "Semiconductor element OFF."

In step S105, the control unit 16 determines whether the current value I 1 _M detected by the first current sensor 14 measured in step S101 is greater than a second threshold value. The second threshold value is smaller than the first threshold value. If the control unit 16 determines that the current value I 1 _M is greater than the second threshold value (Yes in S105), the operation proceeds to step S106. If the control unit 16 determines that the current value I 1 _M is equal to or less than the second threshold value (No in S105), the operation returns to step S101, and the operations from step S101 to step S103 are performed.

In step S106, because the current value I 1 _M detected by the first current sensor 14 is greater than the second threshold value but less than the first threshold value, the control unit 16 switches the semiconductor module 12 to start current-limiting control of the fault current. The reason for starting current-limiting control is that, because the current value I 1 _M is greater than the second threshold value, some kind of fault or overcurrent has occurred, but because the current value I 1 _M is less than the first threshold value, current-limiting control is possible in the semiconductor module 12, and by limiting the current, it is possible to interrupt the current at the multiple switches 21-2N on the load side. In Figure 3, the operation of step S106 is indicated by the phrase "start current-limiting control by semiconductor elements."

FIG. 4 is an explanatory diagram illustrating the operation of the semiconductor circuit breaker selective coordination system 100 according to embodiment 1. In the example of FIG. 4, at timing t0, power is turned on and current begins to flow, but because a short-circuit fault has occurred in the branch circuit of load 41, the current flowing through load 41 increases, causing the overall current to also increase. At timing t1, the control unit 16 detects the fault current, and the semiconductor circuit breaker 1 begins current-limiting control to suppress the increase in current.

In the next step S107, the control unit 16 determines whether the current values I _SW1 to I SWN detected by the second current sensors 31 to 3N measured in step S102 are greater than the reference value I reference, starting with the current value I _SW1 detected by the second current _sensor 31. If the control unit 16 determines that the measured current values I _SW1 to I _SWN are greater than the reference value I _reference (Yes in S107), the operation proceeds to step S109. If the control unit 16 determines that the measured current values I _SW1 to I _SWN are equal to or less than the reference value I _reference (No in S107), the operation proceeds to step S108, and _then to step S107 again to determine the current value I _SW1 of the next branch circuit. This operation is repeated until it is determined in step S107 that I _SW1 to I _SWN are greater than _{the reference value I reference} .

In step S109, the control unit 16 identifies which branch circuit an excessive current has flowed in, based on the current values detected by the multiple second current sensors 31-3N. In Figure 3, the operation of step S109 is indicated by the phrase "identify the fault location in the branch circuit." In the next step S110, the control unit 16 outputs a command to open the contacts to the switch of the branch circuit identified in step S109 from among the multiple switches 21-2N that make up the branch circuits. At this time, the semiconductor module 12 has limited the fault current, so the multiple switches 21-2N are able to interrupt the current. In Figure 3, the operation of step S110 is indicated by the phrase "open the switch of the branch circuit in which the fault was detected."

Furthermore, in the subsequent step S111, since the control unit 16 opened the switch of the branch where the fault occurred in step S110, it stops the current-limiting control by the semiconductor module 12 and turns on the semiconductor module 12. In Figure 3, the operation of step S111 is indicated by the phrase "Stop current-limiting control of semiconductor element and turn semiconductor element ON." The operation related to step S111 will be further explained using Figure 4. At timing t2 in Figure 4, the switch is opened and the current flowing to the load 41 is interrupted, and thereafter the control unit 16 stops the current-limiting control by the semiconductor module 12 and the semiconductor module 12 is turned on, so the current in the load 42 continues to flow.

The semiconductor circuit breaker selective coordination system 100 of embodiment 1 includes a semiconductor circuit breaker 1 that opens and closes an electric circuit 2 using a semiconductor module 12; a first current sensor 14 that measures the current flowing through the semiconductor circuit breaker 1; multiple switches 21-2N connected to the load side of the semiconductor circuit breaker 1 and having open/close contacts; multiple second current sensors 31-3N that measure the current flowing through each of the multiple switches 21-2N; and a control unit 16 that, when a current measurement unit 15 detects a fault current, causes the semiconductor module 12 to perform current limiting control, determines which of the multiple switches 21-2N has the fault current flowing through it based on the current values measured by the multiple second current sensors 31-3N, and, after the current limiting control has been performed, opens the switch determined to have the fault current flowing through it. Therefore, the semiconductor circuit breaker selective coordination system 100 can use switches in branch circuits, allowing for a simple and inexpensive distribution panel configuration. The first current sensor 14, rather than the current measurement unit 15, may detect the fault current. Each of the multiple switches 21-2N may have a semiconductor element instead of a switching contact.

Furthermore, current limiting control is not always performed, but rather the semiconductor circuit breaker 1 immediately performs an interruption if it determines that current limiting control is difficult, so the reliability of the semiconductor circuit breaker selection coordination system 100 as a whole is high.

Each of the multiple switches 21-2N has a low breaking capacity.

Embodiment 2.
FIG. 5 is a diagram illustrating the configuration of a semiconductor circuit breaker selective coordination system 101 according to a second embodiment. In the second embodiment, the semiconductor circuit breaker 1A includes a load characteristic setting unit 17 that sets the load characteristics of the loads 41 to 4N, for example, a threshold value corresponding to the magnitude of the inrush current, for each branch circuit. Furthermore, the load characteristic setting unit 17 has a function of inputting the characteristics of each of the loads 41 to 4N connected to the load sides of the multiple switches 21 to 2N to the control unit 16. With the exception of the load characteristic setting unit 17, the configuration of the semiconductor circuit breaker selective coordination system 101 is the same as the configuration of the semiconductor circuit breaker selective coordination system 100 according to the first embodiment. Therefore, detailed descriptions of the components of the semiconductor circuit breaker selective coordination system 101, other than the load characteristic setting unit 17, are omitted. The control unit 16 detects a fault current based on the characteristics.

Next, the operation of the semiconductor circuit breaker selection coordination system 101 according to the second embodiment will be described with reference to the flowchart shown in Figure 6. Figure 6 is a flowchart showing the procedure of operations performed by the semiconductor circuit breaker 1A included in the semiconductor circuit breaker selection coordination system 101 according to the second embodiment. Figure 6 mainly shows the procedure of operations performed by the control unit 16 included in the semiconductor circuit breaker 1A. Steps S201 to S206 and step S212 are the same as steps S101 to S106 and step S111 in the first embodiment, and therefore detailed explanations of steps S201 to S206 and step S212 will be omitted.

In step S207 after the current limiting control is started in step S206, the control unit 16 sets the current threshold I _reference N for each branch circuit set by the load characteristic setting unit 17, starting from the branch circuit connected to the switch 21.

In the next step S208, the control unit 16 determines whether the current value I _SW N detected by the second current sensor in the set branch circuit is greater than the threshold value I _Reference N. If the control unit 16 determines that the current value I _SW N is greater than the threshold value I _Reference N (Yes in S208), it determines that the branch circuit corresponding to that current value I _SW N is the faulty branch circuit, and the operation proceeds to step S210. If the control unit 16 determines that the current value I _SW N is equal to or less than the threshold value I _Reference N (No in S208), it determines that the branch circuit corresponding to that current value I _SW N is not the faulty branch circuit, and the operation proceeds to step S209 to determine the next branch circuit.

In step S209, the control unit 16 designates the next branch circuit as the branch circuit to be processed next in steps S207 and S208, and the operation returns to step S207. As a result, the operations from step S207 to step S209 are repeated until a branch circuit whose current value I _SW N is greater than the threshold value I _reference N is found in step S208. In Fig. 6, the operation of step S209 is indicated by the phrase "set the next branch circuit to be judged."

In step S210, when a branch circuit having a current value I _SW N greater than the threshold value I _reference N is found, the control unit 16 identifies the branch circuit as the fault circuit. In Fig. 6, the operation of step S210 is indicated by the phrase "identify the fault location of the branch circuit."

In the next step S211, the control unit 16 issues a command to open the switch of the branch circuit identified in step S210, and operation proceeds to the next step S212. In Figure 6, the operation of step S211 is indicated by the phrase "Open the switch of the branch circuit in which the fault was detected."

According to embodiment 2, the semiconductor circuit breaker 1A has a load characteristic setting unit 17 that sets the load characteristics of the multiple loads 41-4N, for example, a threshold value corresponding to the magnitude of the inrush current, for each branch circuit, and can set the load characteristics, for example, a threshold value corresponding to the magnitude of the inrush current, for each branch circuit. Because the semiconductor circuit breaker 1A outputs an opening command to the multiple load-side switches 21-2N, it can detect inrush currents, etc., and suppress the issuance of opening commands to the multiple switches 21-2N.

Embodiment 3.
FIG. 7 is a diagram showing the configuration of a semiconductor circuit breaker selective coordination system 102 according to a third embodiment. The semiconductor circuit breaker selective coordination system 102 does not include the multiple second current sensors 31-3N included in the semiconductor circuit breaker selective coordination system 100 according to the first embodiment. In the third embodiment, the semiconductor circuit breaker 1B includes a wire characteristic setting unit 18 for setting the inductance of the wires connecting the multiple switches 21-2N to each of the loads 41-4N as the characteristics of each of the loads 41-4N connected to the load sides of the multiple switches 21-2N. The configuration of the semiconductor circuit breaker 1B, other than the wire characteristic setting unit 18, is the same as that of the semiconductor circuit breaker 1 according to the first embodiment. FIG. 7 shows multiple resistors 51-5N and multiple inductors 61-6N. The corresponding resistors and inductors schematically represent the electrical configuration of the wires.

FIG. 8 is a diagram showing the state of the electric circuit when semiconductor circuit breaker 1B operates, in order to explain a method for estimating the current of each branch circuit shown in FIG. 7 from the electric wire specifications. As shown in FIG. 8, when semiconductor circuit breaker 1B operates, voltage V is applied across semiconductor circuit breaker 1B. Control unit 16 measures voltage V. Power supply voltage E of electric circuit 11 is also measured in real time, and the value of power supply voltage E is also input to control unit 16. Current value I 1 _M , which is the value of the current flowing through each branch circuit, is measured by first current sensor 14 of semiconductor circuit breaker 1B. Current value I 1 _M is input to control unit 16. In FIG. 8, semiconductor circuit breaker 1B is shown as "SSCB1B," and "I, I ₁ , I ₂ , ..., I _N " represent the currents flowing through the corresponding electric wires.

From FIG. 8, the equation of the electric circuit is expressed by the following formula (1).
ΣL _N (dI _N /dt)=EV-ΣR _N I _N ...(1)
If we transform equation (1) assuming that the dI/dt of a branch circuit that is not experiencing a fault can be ignored, the inductance L of the branch circuit that has experienced a _fault can be expressed by the following equation (2).
L _accident = (EV-ΣR _N I _N )/(dI/dt) ... (2)

Furthermore, since the current is limited by the semiconductor module 12, if it is assumed that ΣR _N I _N due to the resistance value can also be ignored, the inductance L _fault can be expressed by the following equation (3).
L _accident = (EV)/(dI/dt)...(3)
The inductance L _fault is calculated by inputting the measured values of the power supply voltage E, the voltage V, and dI/dt into equation (3).

On the other hand, the inductance _LN of each branch circuit can be calculated by setting the wire diameter, conductor center distance, and wire length of the wires connected to each load using the wire characteristics setting unit 18. Since the fault here is assumed to be a short circuit fault on the load side, the conductor center distance refers to the distance between the centers of the conductors of the wires that make up the sending and returning current in the circuit where the short circuit fault occurred.

Therefore, the control unit 16 selects the inductance L closest to the inductance L fault calculated from the formula (3) from the inductances L _N of each branch circuit calculated from the wire diameter, conductor center distance, and wire length of the wires connected to each switch set by the wire _{characteristics} setting unit 18, estimates that the branch circuit corresponding to that inductance is the fault circuit, and turns off the switch of that circuit.

In addition to the method of calculating the inductance _LN of each branch circuit from the wire diameter, conductor center distance, and wire length of the wire connected to each load as described above, an inductance calculated in advance from the type and length of the wire may be directly input to the wire characteristics setting unit 18, or the inductance per unit length for each type of wire listed in an electric wire handbook or the like may be stored in the wire characteristics setting unit 18, and the inductance may be calculated by inputting the type and length of the wire. The unit of the inductance per unit length is mH/km, and the value of the inductance is, for example, 0.1 to 0.3 mH/km.

After turning off the switch, the control unit 16 again determines whether the fault current has been interrupted based on the dI/dt measured by the first current sensor 14. If the control unit 16 determines that the fault current has not been interrupted, it selects the inductance that is second closest to _{the inductance} L calculated by equation (3) and turns off the switch of the circuit corresponding to the selected inductance. The control unit 16 again determines whether the fault current has been interrupted based on the dI/dt measured by the first current sensor 14. The control unit 16 repeats the above operation to interrupt the fault circuit.

Next, the operation of the semiconductor circuit breaker selection coordination system 102 will be described with reference to the flowchart shown in Fig. 9. Fig. 9 is a flowchart showing the procedure of the operation performed by the semiconductor circuit breaker 1B included in the semiconductor circuit breaker selection coordination system 102 according to the third embodiment. Fig. 9 mainly shows the procedure of the operation performed by the control unit 16 included in the semiconductor circuit breaker 1B. In step S301, the control unit 16 calculates the inductances _L1 to _LN of the wires in each branch circuit from the wire diameter, wire length, etc. of the wires connected to each load set by the wire characteristics setting unit 18. That is, in step S301, the control unit 16 calculates the inductance of each branch circuit from the wire specifications.

Steps S302 to S307 are similar to steps S101, S103 to S106, and S111 in embodiment 1, so detailed explanations of steps S302 to S307 will be omitted.

If the current value I _M measured by the first current sensor 14 is greater than the first threshold value (Yes in S303), the control unit 16 turns off the semiconductor module 12, and if the current value I _M is equal to or less than the first threshold value and greater than the second threshold value (No in S303, Yes in S305), the control unit 16 starts current limiting control in step S306 and then performs inductance estimation processing 300 for the fault branch circuit.

The fault branch circuit inductance estimation process 300 will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the procedure of the operation of the fault branch circuit inductance estimation process 300 in Fig. 9. In step S311, the control unit 16 calculates the inductance L _fault of the branch circuit where the fault occurred based on equation (3).

In step S312, the control unit 16 extracts an inductance closest to the inductance L _fault calculated in step S311 from the inductances L ₁ to L _N of the electric wires in each branch circuit calculated in step S301. In Fig. 10, the operation of step 312 is indicated by the phrase "selection of L _N closest to L _fault ."

In step S313, the control unit 16 opens the switch in the branch circuit of the inductance extracted in step S312. In FIG. 10, the operation of step S313 is indicated by the phrase "open the switch of the branch circuit at the selected L _N. " In step S314, to confirm whether the opened switch is actually the branch circuit where the fault occurred, the control unit 16 measures dI/dt when the semiconductor module 12 is on, based on the current waveform shown in FIG. 11. FIG. 11 is a diagram showing a current waveform when the semiconductor circuit breaker 1B included in the semiconductor circuit breaker selection coordination system 102 according to the third embodiment is performing a current limiting operation. In FIG. 11, Δt, which is the difference between t2 and t1, represents dt in dI/dt, and the difference between c1 and c2 represents dI.

In step S315, the control unit 16 determines whether the dI/dt measured in step S314 is smaller than the third threshold value. If the control unit 16 determines that the dI/dt is smaller than the third threshold value (Yes in S315), it can be determined that the fault circuit has been disconnected by opening the switch in step S313, and the fault branch circuit inductance estimation process 300 ends. Operation proceeds to step S307 in Figure 9.

On the other hand, if the control unit 16 determines that dI/dt is equal to or greater than the third threshold (No in S315), it is determined that the fault circuit has not been interrupted even though the switch was opened in step S313, and the operation proceeds to step S316. In step S316, the control unit 16 closes the switch that was opened in step S313 again. In FIG. 10, the operation of step 316 is indicated by the phrase "close the switch of the branch circuit at L _N. "

In step S317, the control unit 16 excludes from the selection candidates the inductance of the branch circuit whose _switch was opened in step S313 from among the wire inductances _L1 to _LN in each branch circuit calculated in step S301, before extracting the inductance closest to the inductance L fault in the subsequent step S312. In FIG. 10, the operation of step S317 is indicated by the phrase "exclude selected _LN from selection candidates." The operation returns from step S317 to step S312, and the control unit 16 performs the operations from step S312 to step S315.

The semiconductor circuit breaker selection and coordination system 102 according to the third embodiment includes a semiconductor circuit breaker 1B that opens and closes the electric circuit 2 using a semiconductor module 12; a first current sensor 14 that measures the current flowing through the semiconductor circuit breaker 1B; multiple switches 21-2N that are connected to the load side of the semiconductor circuit breaker 1B and have open/close contacts; a wire characteristic setting unit 18 that sets the wire diameter and wire length of the wire connecting the multiple switches 21-2N to each load 41-4N as characteristics of the respective loads 41-4N connected to the load side of the multiple switches 21-2N; and a control unit 16 that, when the first current sensor 14 detects a fault current, causes the semiconductor module 12 to perform current limiting control, selects a switch from the multiple switches 21-2N through which the fault current flows based on the fault current, wire diameter, and wire length, and opens the selected switch after the current limiting control has been performed. This allows switches to be used in branch circuits, resulting in a simple and inexpensive distribution panel.

Furthermore, the semiconductor circuit breaker selection and coordination system 102 can identify the branch circuit in which the fault occurred without requiring a current sensor to measure the current for each of the multiple switches 21-2N, allowing for a simple and inexpensive configuration of the distribution panel.

Furthermore, even if the branch circuit selected by the fault branch circuit inductance estimation process 300 is not the fault circuit, the semiconductor circuit breaker selection coordination system 102 opens the switch, measures dI/dt when the semiconductor module 12 is on, and confirms whether the selected branch circuit was actually the branch circuit that caused the fault. If it is incorrect, it selects the next branch circuit and again checks dI/dt when the semiconductor module 12 is on, thereby ensuring that the fault circuit is shut off.

FIG. 12 is a diagram showing a processor 91 in the case where some or all of the functions of the current measurement unit 15 and control unit 16 of the semiconductor circuit breaker selection coordination system 100 according to embodiment 1 are realized by the processor 91. In other words, some or all of the functions of the current measurement unit 15 and control unit 16 may be realized by the processor 91 executing a program stored in memory 92. The processor 91 is a CPU (Central Processing Unit), processing system, arithmetic system, microprocessor, or DSP (Digital Signal Processor). Memory 92 is also shown in FIG. 12.

When some or all of the functions of the current measurement unit 15 and control unit 16 are realized by the processor 91, those functions are realized by the processor 91 in combination with software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. The processor 91 realizes some or all of the functions of the current measurement unit 15 and control unit 16 by reading and executing the program stored in the memory 92.

When some or all of the functions of the current measurement unit 15 and control unit 16 are implemented by the processor 91, the semiconductor circuit breaker selection coordination system 100 has a memory 92 for storing a program that results in some or all of the steps executed by the current measurement unit 15 and control unit 16. It can also be said that the program stored in the memory 92 causes a computer to execute some or all of the procedures or methods executed by the current measurement unit 15 and control unit 16.

Memory 92 may be, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disk).

FIG. 13 is a diagram showing the processing circuit 93 when some or all of the functions of the current measurement unit 15 and control unit 16 of the semiconductor circuit breaker selection coordination system 100 according to embodiment 1 are realized by the processing circuit 93. In other words, some or all of the functions of the current measurement unit 15 and control unit 16 may be realized by the processing circuit 93.

The processing circuit 93 is dedicated hardware. The processing circuit 93 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these.

Some of the functions of the current measurement unit 15 and the control unit 16 may be realized by dedicated hardware separate from the hardware that realizes the remaining functions of the current measurement unit 15 and the control unit 16.

Some of the functions possessed by the current measurement unit 15 and the control unit 16 may be realized by software or firmware, and the remaining functions may be realized by dedicated hardware. In this way, the functions possessed by the current measurement unit 15 and the control unit 16 can be realized by hardware, software, firmware, or a combination of these.

Some or all of the functions of the current measurement unit 15, control unit 16, and load characteristic setting unit 17 of the semiconductor circuit breaker selection coordination system 101 according to embodiment 2 may be implemented by a processor or a processing circuit. The processor is the same as processor 91. The processing circuit is the same as processing circuit 93.

Some or all of the functions of the current measurement unit 15, control unit 16, and wire characteristic setting unit 18 of the semiconductor circuit breaker selection coordination system 102 according to embodiment 3 may be implemented by a processor or a processing circuit. The processor is the same as processor 91. The processing circuit is the same as processing circuit 93.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. Parts of the configuration may also be omitted or modified without departing from the spirit of the invention.

1, 1A, 1B: semiconductor circuit breaker, 2: electrical path, 11: electrical circuit, 12: semiconductor module, 13: mechanical element, 14: first current sensor, 15: current measurement unit, 16: control unit, 17: load characteristics setting unit, 18: electrical wire characteristics setting unit, 21-2N: switches, 31-3N: second current sensors, 41-4N: loads, 51-5N: resistors, 61-6N: inductors, 91: processor, 92: memory, 93: processing circuit, 100, 101, 102: semiconductor circuit breaker selection and coordination system, 121: semiconductor element, 122, 123: terminals, 124: diode, 300: inductance estimation process for faulted branch circuit.

Claims (5)

a semiconductor circuit breaker that opens and closes an electric circuit using a semiconductor element;
a first current sensor that measures a current flowing through the semiconductor circuit breaker;
A plurality of switches connected to the load side of the semiconductor circuit breaker;
a plurality of second current sensors that measure currents flowing through the plurality of switches;
a control unit that, when the first current sensor detects a fault current, causes the semiconductor element to perform current-limiting control, determines a switch through which the fault current has flowed from among the plurality of switches based on the currents measured by the plurality of second current sensors, and causes the switch to perform an opening operation after the current-limiting control has been performed;
A selective coordination system for semiconductor circuit breakers, characterized in that each of the plurality of switches has a switching contact or a semiconductor element. a load characteristic setting unit that inputs characteristics of each load connected to the load side of the plurality of switches to the control unit;
The semiconductor circuit breaker selective coordination system according to claim 1 , wherein the control unit detects the fault current based on the characteristics. The semiconductor circuit breaker selective coordination system according to claim 2 , wherein the characteristic is the magnitude of an inrush current. a semiconductor circuit breaker that opens and closes an electric circuit using a semiconductor element;
a first current sensor that measures a current flowing through the semiconductor circuit breaker;
a plurality of switches connected to the load side of the semiconductor circuit breaker and having switching contacts;
a wire characteristic setting unit that sets characteristics of wires connecting the plurality of switches and each of the loads as characteristics of each of the loads connected to the load sides of the plurality of switches;
a control unit that, when the first current sensor detects a fault current, causes the semiconductor element to perform current-limiting control, selects a switch through which the fault current has flowed from among the plurality of switches based on the fault current, the diameter of the electric wire, and the length of the electric wire, and causes the switch to open after the current-limiting control has been performed. The semiconductor circuit breaker selection coordination system according to any one of claims 1 to 4, wherein each of the plurality of switches is a circuit breaker with a low breaking capacity.