Selective cooperation system for semiconductor circuit breaker

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

[0001] The present disclosure relates to a semiconductor circuit breaker selection coordination system in which a semiconductor circuit breaker is used as a main circuit breaker and a branch side is used as a switch.

[0002] A selective circuit breaker has been known which includes a main circuit breaker, a current reduction means for temporarily reducing an overcurrent when an overcurrent flows due to an accident, and a plurality of branch circuit breakers provided on branch-side circuits, and which shuts off the branch circuit breaker when an accident occurs on the secondary side of the branch circuit breaker, and shuts off the branch circuit breaker when the overcurrent does not return to a set value or less even after a predetermined time has elapsed after the accident (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 5-15053

[0004] However, conventional technology has the problem that 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 the branch circuit breakers also need to have the breaking capacity to interrupt short-circuit current.There is a demand for a simple and inexpensive configuration of the distribution board.

[0005] The present disclosure has been made in view of the above, and aims to provide a selective coordination system for semiconductor circuit breakers that allows a distribution panel to be configured simply and inexpensively.

[0006] In order to solve the above-mentioned problems and achieve the object, the semiconductor circuit breaker selection coordination system according to the present disclosure includes 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, a plurality of switches connected to the load side of the semiconductor circuit breaker, a plurality of second current sensors that measure the current flowing in each of the plurality of switches, and a control unit that causes the semiconductor element to perform current-limiting control when the first current sensor detects a fault current, identifies a switch from the plurality of switches through which the fault current has flowed based on the currents measured by the plurality of second current sensors, and opens the switch after the current-limiting control has been performed. Each of the plurality of switches has an open / close contact or a semiconductor element.

[0007] The semiconductor circuit breaker selection coordination system according to the present disclosure has the effect of enabling a distribution panel to be configured simply and inexpensively.

[0008] FIG. 1 is a diagram showing the configuration of a semiconductor circuit breaker selection coordination system according to embodiment 1. FIG. 2 is a diagram showing the configuration of a single pole of a semiconductor module in a semiconductor circuit breaker provided in the semiconductor circuit breaker selection coordination system according to embodiment 1. FIG. 3 is a flowchart showing the procedure of operation performed by a semiconductor circuit breaker provided in the semiconductor circuit breaker selection coordination system according to embodiment 1. FIG. 4 is an explanatory diagram for explaining the operation of the semiconductor circuit breaker selection coordination system according to embodiment 1. FIG. 5 is a diagram showing the configuration of a semiconductor circuit breaker selection coordination system according to embodiment 2. FIG. 6 is a flowchart showing the procedure of operation performed by a semiconductor circuit breaker provided in the semiconductor circuit breaker selection coordination system according to embodiment 2. FIG. 7 is a diagram showing the configuration of a semiconductor circuit breaker selection coordination system according to embodiment 3. 9 is a diagram showing the state of an electric circuit when a semiconductor circuit breaker operates to estimate the inductance of the faulted branch circuit of FIG. 9; a flowchart showing the procedure of the operation performed by a semiconductor circuit breaker provided in a semiconductor circuit breaker selection coordination system according to embodiment 3; a flowchart showing the procedure of the operation of the inductance estimation process of the faulted branch circuit of FIG. 9; a diagram showing a current waveform when a semiconductor circuit breaker provided in a semiconductor circuit breaker selection coordination system according to embodiment 3 is performing a current limiting operation; a diagram showing a processor when part or all of the functions of a current measurement unit and a control unit provided in a semiconductor circuit breaker selection coordination system according to embodiment 1 are realized by a processor; a diagram showing a processing circuit when part or all of the functions of a current measurement unit and a control unit provided in a semiconductor circuit breaker selection coordination system according to embodiment 1 are realized by a processing circuit;

[0009] Hereinafter, a semiconductor circuit breaker selective coordination system according to an embodiment will be described in detail with reference to the drawings.

[0010] First Embodiment. FIG. 1 is a diagram showing the configuration of a semiconductor circuit breaker selective coordination system 100 according to a first embodiment. The semiconductor circuit breaker selective coordination system 100 includes a semiconductor circuit breaker 1 that interrupts an electric circuit 2 using a semiconductor element. The semiconductor element is a semiconductor module 12, which will be described later. The semiconductor circuit breaker selective 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.

[0011] Each of the multiple second current sensors 31 to 3N is connected to a corresponding load. FIG. 1 shows multiple loads 41 to 4N. The number of the multiple loads 41 to 4N is the same as the number of the multiple second current sensors 31 to 3N. For example, the load 41 is connected to the second current sensor 31, and the load 4N ​​is connected to the second current sensor 3N. Each of the multiple second current sensors 31 to 3N detects the current flowing through the corresponding load. For example, the second current sensor 31 detects the current flowing through the load 41, and the second current sensor 3N detects the current flowing through the load 4N.

[0012] The semiconductor circuit breaker 1 includes a semiconductor module 12 that is provided on an electric circuit 2 and that turns on and off a current flowing through the electric circuit 2, a mechanical element 13 that is provided on the electric circuit 2 in series with the semiconductor module 12 and that opens and closes the electric circuit 2, a first current sensor 14 that detects a current flowing through the electric circuit 2, a current measurement unit 15 that receives an output signal from the first current sensor 14 and measures the current flowing through the electric 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 plurality of second current sensors 31 to 3N are also input to the current measurement unit 15.

[0013] In the first embodiment, the semiconductor module 12 and the mechanical element 13 are, for example, three-pole elements corresponding to three-phase AC. Fig. 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 the first embodiment. That is, Fig. 2 shows the single-pole structure of the semiconductor module 12 shown in Fig. 1. The single-pole structure shown in Fig. 2 is a structure that is responsible for energizing and blocking for each phase. Each of the semiconductor module 12 and the mechanical element 13 is provided with three identical structures corresponding to the three power lines of the U phase, V phase, and W phase.

[0014] 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 an electric circuit connecting a power source and a load, and when the state of the semiconductor element 121 is switched from on to off, it interrupts the current in the electric circuit.

[0015] The semiconductor element 121 has a unidirectional blocking capability. The semiconductor element 121 is, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). If the semiconductor element 121 is a MOSFET, one terminal 122 of the semiconductor element 121 is a drain terminal, and the other terminal 123 of the semiconductor element 121 is a source terminal. If the semiconductor element 121 is an IGBT, one terminal 122 is a collector terminal, and the other terminal 123 is an emitter terminal. The semiconductor element 121 can block only current of the polarity flowing from the terminal 122 to the terminal 123.

[0016] In order to provide the semiconductor module 12 with bidirectional blocking capability, i.e., blocking both forward and reverse currents, the semiconductor module 12 has two semiconductor elements 121 connected in series with the terminal 122 of one semiconductor element 121 facing the terminal 122 of the other semiconductor element 121, as shown in FIG. 2 . Alternatively, the two semiconductor elements 121 may 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.

[0017] Next, the operation of the semiconductor circuit breaker selection coordination system 100 will be described with reference to the flowchart of Fig. 3. Fig. 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. Fig. 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 detected by the first current sensor 14. Ｍ In step S102, the current measurement unit 15 measures the current value I detected by each of the second current sensors 31 to 3N. ＳＷ 1-I ＳＷ Measure N.

[0018] In step S103, the control unit 16 calculates the current value I detected by the first current sensor 14 measured in step S101. Ｍ It is determined whether the current value I is greater than a first threshold value. Ｍ If the control unit 16 determines that the current value I is greater than the first threshold value (Yes in S103), the operation proceeds to step S104. Ｍ If the control unit 16 determines that the difference is equal to or less than the first threshold value (No in S103), the operation proceeds to step S105.

[0019] In step S104, the control unit 16 immediately turns off the semiconductor module 12 to cut 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 FIG. 3, the operation of step S104 is indicated by the phrase "Semiconductor element OFF."

[0020] In step S105, the control unit 16 calculates the current value I detected by the first current sensor 14 measured in step S101. Ｍ It is determined whether the current value I is greater than a second threshold value, which is less than the first threshold value. Ｍ If the control unit 16 determines that the current value I is greater than the second threshold value (Yes in S105), the operation proceeds to step S106. Ｍ If the control unit 16 determines that the difference 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.

[0021] In step S106, the current value I detected by the first current sensor 14 is Ｍ is greater than the second threshold value and equal to or less than the first threshold value, the control unit 16 causes the semiconductor module 12 to perform a switching operation and starts current limiting control of the fault current. Ｍ is greater than the second threshold, some accident or overcurrent has occurred, but the current value I Ｍ is equal to or less than the first threshold, current limiting control is possible in the semiconductor module 12, and current limiting makes it possible to interrupt current in the multiple switches 21 to 2N on the load side. In Figure 3, the operation of step S106 is indicated by the phrase "start current limiting control by semiconductor element."

[0022] 4 is an explanatory diagram for explaining the operation of the semiconductor circuit breaker selective coordination system 100 according to the first embodiment. In the example of FIG. 4, at timing t0, power is turned on and current begins to flow, but because a short circuit fault occurs in the branch circuit of the load 41, the current flowing through the load 41 increases, and the overall current also increases. At timing t1, the control unit 16 detects the fault current, and the semiconductor circuit breaker 1 starts current limiting control to suppress the increase in current.

[0023] In the next step S107, the control unit 16 calculates the current values ​​I detected by the second current sensors 31 to 3N measured in step S102. ＳＷ 1-I ＳＷ For N, the current value I detected by the second current sensor 31 is ＳＷ Reference value I in order from 1 基準 Determine whether the measured current values ​​I are greater than or equal to the ＳＷ 1-I ＳＷ N is the reference value I 基準 If the control unit 16 determines that the measured current values ​​I are greater than the reference current (Yes in S107), the operation proceeds to step S109. ＳＷ 1-I ＳＷ N is the reference value I 基準 If the control unit 16 determines that the current value I of the next branch circuit is equal to or less than the predetermined value (No in S107), the operation proceeds to step S108. ＳＷ In order to make a determination as to whether the value is I or I, the process proceeds to step S107 again. ＳＷ 1-I ＳＷ N is the reference value I 基準 This operation is repeated until it is determined to be greater.

[0024] 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 to 3N. In FIG. 3, the operation of step S109 is indicated by the phrase "identify the fault location of the branch circuit." In the next step S110, the control unit 16 outputs a command to open the contacts of the switch of the branch circuit identified in step S109 from among the multiple switches 21 to 2N that are branch circuits. At this time, the semiconductor module 12 limits the fault current, so the multiple switches 21 to 2N can interrupt the current. In FIG. 3, the operation of step S110 is indicated by the phrase "open the switch of the branch circuit in which the fault was detected."

[0025] Furthermore, in subsequent step S111, since the control unit 16 opened the switch of the branch where the fault occurred in step S110, the control unit 16 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 on semiconductor element." 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. 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.

[0026] The semiconductor circuit breaker selective coordination system 100 according to the first embodiment 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 switching 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 a 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 is performed, opens the switch determined to have a 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 plurality of switches 21 to 2N may have a semiconductor element instead of a switching contact.

[0027] Furthermore, current limiting control is not always performed, but the semiconductor circuit breaker 1 immediately performs an interruption when it is determined that current limiting control is difficult, so the reliability of the semiconductor circuit breaker selection coordination system 100 as a whole is high.

[0028] Each of the plurality of switches 21 to 2N is a circuit breaker with a low breaking capacity.

[0029] Second Embodiment. FIG. 5 is a diagram showing the configuration of a semiconductor circuit breaker selection 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 side of the plurality of 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 selection coordination system 101 is the same as the configuration of the semiconductor circuit breaker selection coordination system 100 according to the first embodiment. Therefore, detailed description of the components of the semiconductor circuit breaker selection coordination system 101, other than the load characteristic setting unit 17, will be omitted. The control unit 16 detects a fault current based on the characteristics.

[0030] 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 Fig. 6. Fig. 6 is a flowchart showing the procedure of the operation performed by the semiconductor circuit breaker 1A included in the semiconductor circuit breaker selection coordination system 101 according to the second embodiment. Fig. 6 mainly shows the procedure of the operation 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 description of steps S201 to S206 and step S212 will be omitted.

[0031] In step S207 after the current limiting control is started in step S206, the control unit 16 sets the current threshold value I for each branch circuit set by the load characteristic setting unit 17 in order from the branch circuit connected to the switch 21. 基準 Set N.

[0032] In the next step S208, the control unit 16 calculates the current value I detected by the second current sensor in the set branch circuit. ＳＷ N is the threshold I 基準 The control unit 16 determines whether the current value I ＳＷ N is the threshold I 基準If it is determined that the current value is greater than N (Yes in S208), ＳＷ The control unit 16 determines that the branch circuit corresponding to N is the branch circuit in fault, and the operation proceeds to step S210. ＳＷ N is the threshold I 基準 If it is determined that the current value is equal to or less than N (No in S208), ＳＷ It is determined that the branch circuit corresponding to N is not the branch circuit in the fault, and the operation proceeds to step S209 to determine the next branch circuit.

[0033] 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. ＳＷ N is the threshold I 基準 The operations from step S207 to step S209 are repeated until a branch circuit greater than N is found. In Fig. 6, the operation of step S209 is indicated by the phrase "set the next branch circuit to be determined."

[0034] Current value I ＳＷ N is the threshold I 基準 In step S210, when a branch circuit having a number greater than N is found, the control unit 16 identifies that branch circuit as the fault circuit. In Fig. 6, the operation of step S210 is indicated by the phrase "identify fault location of branch circuit."

[0035] 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 the operation proceeds to the next step S212. In Fig. 6, the operation of step S211 is indicated by the phrase "open the switch of the branch circuit in which the fault was detected."

[0036] According to the second embodiment, the semiconductor circuit breaker 1A has a load characteristic setting unit 17 that sets the load characteristics of the plurality of loads 41 to 4N, for example, a threshold value corresponding to the magnitude of an inrush current, for each branch circuit, and the load characteristics, for example, a threshold value corresponding to the magnitude of an inrush current, can be set for each branch circuit. The semiconductor circuit breaker 1A outputs an opening command to the plurality of switches 21 to 2N on the load side, and can therefore detect an inrush current or the like and suppress the issuance of an opening command to the plurality of switches 21 to 2N.

[0037] Third Embodiment. Figure 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 have the multiple second current sensors 31-3N that the semiconductor circuit breaker selective coordination system 100 according to the first embodiment has. In the third embodiment, the semiconductor circuit breaker 1B has a wire characteristic setting unit 18 for setting the inductance of the wires connecting the multiple switches 21-2N and each load 41-4N as the characteristics of each load 41-4N connected to the load side 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. Figure 7 shows multiple resistors 51-5N and multiple inductors 61-6N. The corresponding resistors and inductors schematically represent the electrical configuration of the wires.

[0038] 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, which is the value of the current flowing through each branch circuit, is Ｍ is measured by the first current sensor 14 of the semiconductor circuit breaker 1B. Ｍ are input to the control unit 16. In FIG. 8, the semiconductor circuit breaker 1B is shown as "SSCB1B" and "I, I １ , I ２ , ..., I Ｎ" means the current flowing through the corresponding wire.

[0039] From FIG. 8, the equation of the electric circuit is expressed by the following equation (1): ΣL Ｎ (dI Ｎ / dt)=EV-ΣR Ｎ I Ｎ ...(1) If we assume that the dI / dt of the branch circuit that is not experiencing an accident can be ignored and rearrange the equation (1), we get the inductance L of the branch circuit where the accident occurred. 事故 is expressed by the following formula (2): 事故 = (EV-ΣR Ｎ I Ｎ ) / (dI / dt)...(2)

[0040] In addition, since the current is limited by the semiconductor module 12, the ΣR Ｎ I Ｎ If we can also ignore the inductance L 事故 is expressed by the following formula (3): 事故 = (EV) / (dI / dt) (3) By inputting the measured values ​​of the power supply voltage E, the voltage V, and dI / dt into equation (3), the inductance L 事故 is calculated.

[0041] On the other hand, the wire characteristic setting unit 18 sets the wire diameter, conductor center distance, and wire length of the wire connected to each load, thereby Ｎ 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.

[0042] Therefore, the control unit 16 calculates the inductance L of each branch circuit calculated from the wire diameter, conductor center distance, and wire length of the wire connected to each switch set by the wire characteristic setting unit 18. Ｎ Among these, the inductance L calculated from equation (3) 事故 The inductance closest to this is selected, the branch circuit corresponding to this inductance is assumed to be the fault circuit, and the switch for that circuit is turned off.

[0043] In addition, the inductance L of each branch circuit Ｎ Regarding the inductance, in addition to the method of calculating it from the wire diameter, conductor center distance, and wire length of the wires 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.

[0044] 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 uses the inductance L calculated by the formula (3) 事故 The control unit 16 then selects the inductance that is second closest to the fault current 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.

[0045] 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 inductance L of the wire in each branch circuit from the wire diameter, wire length, etc. of the wire connected to each load set by the wire characteristic setting unit 18. １ ~L Ｎ That is, in step S301, the control unit 16 calculates the inductance of each branch circuit from the electric wire specifications.

[0046] Steps S302 to S307 are similar to step S101, step S103 to step S106, and step S111 in the first embodiment, and therefore detailed description of steps S302 to S307 will be omitted.

[0047] The control unit 16 detects the current value I measured by the first current sensor 14. Ｍ is greater than the first threshold value (Yes in S303), the semiconductor module 12 is turned off, and the current value I Ｍ If is equal to or smaller than the first threshold and larger than the second threshold (No in S303, Yes in S305), current limiting control is started in step S306, and then the inductance estimation process 300 of the faulted branch circuit is performed.

[0048] 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 of the branch circuit where the fault occurred based on equation (3). 事故 Calculate.

[0049] In step S312, the control unit 16 calculates the inductance L of the electric wire in each branch circuit calculated in step S301. １ ~L Ｎ Among these, the inductance L calculated in step S311 事故 In FIG. 10, the operation of step 312 is "L 事故 Close to L Ｎ This is indicated by the phrase "selection."

[0050] In step S313, the control unit 16 opens the switch in the branch circuit of the inductance extracted in step S312. ＮIn step S314, in order to confirm whether the opened switch is really the branch circuit in which the accident 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, and Δt, which is the difference between t2 and t1 in FIG. 11, represents dt in dI / dt, and the difference between c1 and c2 represents dI.

[0051] In step S315, the control unit 16 determines whether the dI / dt measured in step S314 is smaller than the third threshold. If the control unit 16 determines that the dI / dt is smaller than the third threshold (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. The operation proceeds to step S307 in FIG. 9.

[0052] On the other hand, if the control unit 16 determines that dI / dt is equal to or greater than the third threshold value (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 in step S316 is "L Ｎ This is indicated by the words "close the branch circuit breaker in the

[0053] In step S317, the control unit 16 determines whether the inductance L 事故 Before extracting the inductance closest to １ ~L Ｎ In step S313, the inductance of the branch circuit whose switch is opened is excluded from the selection targets. ＮThe operation returns from step S317 to step S312, and the control unit 16 performs the operations from step S312 to step S315.

[0054] A semiconductor circuit breaker selection coordination system 102 according to a third embodiment includes a semiconductor circuit breaker 1B 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 1B, a plurality of switches 21 to 2N that are connected to the load side of the semiconductor circuit breaker 1B and have opening and closing contacts, a wire characteristic setting unit 18 that sets the wire diameter and wire length of the wire connecting the plurality of switches 21 to 2N to each of the loads 41 to 4N as characteristics of the wire, 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 plurality of switches 21 to 2N through which the fault current flows based on the fault current, the wire diameter, and the wire length, and opens the switch after the current limiting control is performed. This allows switches to be used in branch circuits, resulting in a simple and inexpensive distribution panel.

[0055] Furthermore, the semiconductor circuit breaker selection coordination system 102 can identify the branch circuit in which an accident has occurred without having a current sensor that measures the current for each of the multiple switches 21 to 2N, allowing for a simple and inexpensive configuration of the distribution board.

[0056] 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 is really 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, so that the fault circuit can be reliably shut off.

[0057] 12 is a diagram illustrating a processor 91 in a case where some or all of the functions of the current measurement unit 15 and the control unit 16 included in the semiconductor circuit breaker selection coordination system 100 according to the first embodiment are realized by the processor 91. In other words, some or all of the functions of the current measurement unit 15 and the control unit 16 may be realized by the processor 91 that executes a program stored in a memory 92. The processor 91 is a CPU (Central Processing Unit), a processing system, an arithmetic system, a microprocessor, or a DSP (Digital Signal Processor). The memory 92 is also shown in FIG.

[0058] When some or all of the functions of the current measurement unit 15 and the control unit 16 are realized by the processor 91, the functions are realized by the processor 91 and 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 the control unit 16 by reading and executing the program stored in the memory 92.

[0059] When some or all of the functions of the current measurement unit 15 and the control unit 16 are realized 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 the 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 the control unit 16.

[0060] The memory 92 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (registered trademark) (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).

[0061] 13 is a diagram illustrating a processing circuit 93 in a case where some or all of the functions of the current measurement unit 15 and the control unit 16 included in the semiconductor circuit breaker selection coordination system 100 according to the first embodiment are realized by the processing circuit 93. In other words, some or all of the functions of the current measurement unit 15 and the control unit 16 may be realized by the processing circuit 93.

[0062] The processing circuitry 93 is dedicated hardware, and 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 thereof.

[0063] Some of the functions of the current measurement unit 15 and the control unit 16 may be realized by dedicated hardware that is separate from the hardware that realizes the remaining functions of the current measurement unit 15 and the control unit 16.

[0064] Some of the functions of the current measurement unit 15 and the control unit 16 may be implemented by software or firmware, and the remaining functions may be implemented by dedicated hardware. In this way, the functions of the current measurement unit 15 and the control unit 16 can be implemented by hardware, software, firmware, or a combination of these.

[0065] Some or all of the functions of the current measurement unit 15, the control unit 16, and the load characteristic setting unit 17 included in the semiconductor circuit breaker selection coordination system 101 according to the second embodiment may be realized by a processor or a processing circuit. The processor is a processor similar to the processor 91. The processing circuit is a processing circuit similar to the processing circuit 93.

[0066] Some or all of the functions of the current measurement unit 15, the control unit 16, and the wire characteristics setting unit 18 included in the semiconductor circuit breaker selection coordination system 102 according to the third embodiment may be realized by a processor or a processing circuit. The processor is the same as the processor 91. The processing circuit is the same as the processing circuit 93.

[0067] 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, or part of the configuration may be omitted or modified within the scope of the gist of the invention.

[0068] 1, 1A, 1B semiconductor circuit breaker, 2 electric circuit, 11 electric circuit, 12 semiconductor module, 13 mechanical element, 14 first current sensor, 15 current measurement unit, 16 control unit, 17 load characteristic setting unit, 18 electric wire characteristic setting unit, 21 to 2N switches, 31 to 3N second current sensors, 41 to 4N loads, 51 to 5N resistors, 61 to 6N inductors, 91 processor, 92 memory, 93 processing circuit, 100, 101, 102 semiconductor circuit breaker selection coordination system, 121 semiconductor element, 122, 123 terminal, 124 diode, 300 inductance estimation process of fault branch circuit.

Claims

1. A selective coordination system for semiconductor circuit breakers, comprising: 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 said semiconductor circuit breaker; a plurality of switches connected to the load side of said semiconductor circuit breaker; a plurality of second current sensors that measure the current flowing in each of said plurality of switches; and a control unit that, when said first current sensor detects a fault current, causes said semiconductor element to perform current-limiting control, determines from said plurality of switches through which said fault current has flowed based on the currents measured by said plurality of second current sensors, and causes said switch to open after said current-limiting control has been performed, wherein each of said plurality of switches has an open / close contact or a semiconductor element.

2. The semiconductor circuit breaker selective coordination system according to claim 1, further comprising a load characteristic setting unit that inputs the characteristics of each load connected to the load side of the plurality of switches to the control unit, and the control unit detects the fault current based on the characteristics.

3. The semiconductor circuit breaker selective coordination system according to claim 2, wherein the characteristic is the magnitude of an inrush current.

4. A selective coordination system for semiconductor circuit breakers comprising: 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; a plurality of switches connected to the load side of the semiconductor circuit breaker and having open / close contacts; a wire characteristic setting unit that sets the characteristics of the wires connecting the plurality of switches to each of the loads as the characteristics of each of the loads connected to the load sides of the plurality of switches; and a control unit that, when the first current sensor detects a fault current, causes the semiconductor element to perform current limiting control, selects from the plurality of switches a switch through which the fault current has flowed based on the fault current, the diameter and length of the wire, and causes the switch to open after the current limiting control has been performed.

5. A selective coordination system for semiconductor circuit breakers according to any one of claims 1 to 4, characterized in that each of the plurality of switches is a circuit breaker with a low breaking capacity.

Images