Selective coordination system for semiconductor circuit breakers

Abstract

The semiconductor circuit breaker selection coordination system (100) includes: a semiconductor circuit breaker (1) that switches the circuit (2) on and off via a semiconductor module (12); a first current sensor (14) that measures the current flowing in the semiconductor circuit breaker (1); a plurality of switches (21-2N) connected to the load side of the semiconductor circuit breaker (1); a plurality of second current sensors (31-3N) that measure the current flowing in each of the plurality of switches (21-2N); and a control unit (16) that, if an emergency current is detected by the first current sensor (14), causes the semiconductor module (12) to perform current limiting control, determines the switch from the plurality of switches (21-2N) that is flowing with the emergency current based on the current measured by the plurality of second current sensors (31-3N), and causes that switch to disconnect after performing current limiting control. Each of the plurality of switches (21-2N) has an opening / closing contact or a semiconductor element.

Description

Technical Field

[0001] This invention relates to a selection coordination system for semiconductor circuit breakers that are configured as main circuit breakers and whose branch sides are openers / closers. Background Technology

[0002] Previously, a selective circuit breaker was known, comprising: a main circuit breaker; a current reduction unit that temporarily reduces an overcurrent when an overcurrent flows due to an accident; and a plurality of branch circuit breakers disposed on branch-side circuits, which disconnect the branch circuit breaker when an accident occurs on the secondary side of the branch circuit breaker, and disconnect the branch circuit breaker if the overcurrent has not recovered to less than or equal to a set value even after a predetermined time following the accident (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 5-15053 Summary of the Invention

[0004] However, existing technologies have the following drawbacks: due to the low current-limiting performance of main circuit breakers, mechanical circuit breakers are also configured in branch circuit breakers, which also need to have breaking capacity capable of interrupting short-circuit currents. There is a desire for a simple and inexpensive way to construct switchboards.

[0005] The present invention was made in view of the above circumstances, and its object is to provide a selection coordination system for semiconductor circuit breakers that can be simply and inexpensively constructed into a distribution panel.

[0006] To address the aforementioned issues and achieve the objective, the semiconductor circuit breaker selection and coordination system of the present invention comprises: a semiconductor circuit breaker that switches the circuit on and off using semiconductor elements; 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, if an emergency current is detected by the first current sensor, causes the semiconductor elements to perform current-limiting control, determines the switch from the plurality of switches that is flowing with the emergency current based on the current measured by the plurality of second current sensors, and causes the switch to open after performing current-limiting control. Each of the plurality of switches has an opening / closing contact or a semiconductor element.

[0007] The effects of the invention

[0008] The semiconductor circuit breaker selection coordination system of the present invention has the advantage of being able to construct a distribution panel simply and inexpensively. Attached Figure Description

[0009] Figure 1This is a diagram showing the structure of the selection coordination system for the semiconductor circuit breaker involved in Embodiment 1.

[0010] Figure 2 This is a diagram showing the unipolar structure of the semiconductor module in the semiconductor circuit breaker of the semiconductor circuit breaker selection coordination system according to Embodiment 1.

[0011] Figure 3 This is a flowchart illustrating the operation of the semiconductor circuit breaker in the semiconductor circuit breaker selection and coordination system according to Embodiment 1.

[0012] Figure 4 This is an explanatory diagram used to illustrate the operation of the selection coordination system for the semiconductor circuit breaker according to Embodiment 1.

[0013] Figure 5 This is a diagram showing the structure of the selection coordination system for the semiconductor circuit breaker involved in Embodiment 2.

[0014] Figure 6 This is a flowchart illustrating the operation of the semiconductor circuit breaker in the semiconductor circuit breaker selection and coordination system according to Embodiment 2.

[0015] Figure 7 This is a diagram showing the structure of the selection coordination system for the semiconductor circuit breaker involved in Embodiment 3.

[0016] Figure 8 This is to explain the difference between wire specifications and wire specifications. Figure 7 The method for estimating the current in each branch circuit is shown, and a diagram showing the state of the electrical circuit when the semiconductor circuit breaker operates is presented.

[0017] Figure 9 This is a flowchart illustrating the operation of the semiconductor circuit breaker in the semiconductor circuit breaker selection and coordination system according to Embodiment 3.

[0018] Figure 10 It means Figure 9 The flowchart shows the operation process of inductance estimation handling for the fault branch circuit.

[0019] Figure 11 This is a diagram showing the current waveform of the semiconductor circuit breaker in the selection and coordination system of the semiconductor circuit breaker according to Embodiment 3 when it performs current limiting operation.

[0020] Figure 12 This is a diagram of a processor in the case where some or all of the functions of the current measurement unit and control unit of the semiconductor circuit breaker selection coordination system according to Embodiment 1 are implemented by a processor.

[0021] Figure 13 This is a diagram showing the processing circuit in which some or all of the functions of the current measurement unit and control unit of the semiconductor circuit breaker selection coordination system according to Embodiment 1 are implemented by the processing circuit. Detailed Implementation

[0022] The selection and coordination system for semiconductor circuit breakers according to the embodiments will now be described in detail based on the accompanying drawings.

[0023] Implementation Method 1

[0024] Figure 1 This diagram illustrates the structure of the semiconductor circuit breaker selection coordination system 100 according to Embodiment 1. The semiconductor circuit breaker selection coordination system 100 includes a semiconductor circuit breaker 1, which disconnects circuit 2 via a semiconductor element. This semiconductor element is the semiconductor module 12 described later. The semiconductor circuit breaker selection coordination system 100 also includes: a plurality of switches 21 to 2N connected in parallel to the load side of the semiconductor circuit breaker 1; and a plurality of second current sensors 31 to 3N. The number of the plurality of second current sensors 31 to 3N is the same as the number of switches 21 to 2N. Each of the plurality of second current sensors 31 to 3N is connected to a corresponding switch among the plurality of switches 21 to 2N. For example, second current sensor 31 is connected to switch 21, and second current sensor 3N is connected to switch 2N.

[0025] Multiple second current sensors 31 to 3N are each connected to a corresponding load. Figure 1 The diagram shows multiple loads 41 to 4N. The number of loads 41 to 4N is the same as the number of second current sensors 31 to 3N. For example, second current sensor 31 is connected to load 41, and second current sensor 3N is connected to load 4N. Each of the second current sensors 31 to 3N detects the current flowing in its corresponding load. For example, second current sensor 31 detects the current flowing in load 41, and second current sensor 3N detects the current flowing in load 4N.

[0026] The semiconductor circuit breaker 1 includes: a semiconductor module 12 disposed in a circuit 2 for connecting and disconnecting the current flowing in the circuit 2; a mechanical element 13 disposed in series with the semiconductor module 12 in the circuit 2 for switching the circuit 2 on and off; a first current sensor 14 for detecting the current flowing in the circuit 2; a current measuring unit 15, which receives the output signal from the first current sensor 14 and measures the current flowing in the circuit 2; and a control unit 16 for controlling the semiconductor module 12 and the mechanical element 13 based on the current value measured by the current measuring unit 15. Current values ​​detected by a plurality of second current sensors 31 to 3N are also input to the current measuring unit 15.

[0027] In embodiment 1, the semiconductor module 12 and the mechanical element 13 are, for example, three-pole elements corresponding to three-phase AC. Figure 2 This is a diagram illustrating the unipolar structure of the semiconductor module 12 in the semiconductor circuit breaker 1 of the semiconductor circuit breaker selection coordination system 100 according to Embodiment 1. That is, Figure 2 It shows Figure 1 The semiconductor module 12 shown has a unipolar structure. Figure 2 The unipolar configuration shown is responsible for energizing and de-energizing each phase. Three identical configurations are provided in the semiconductor module 12 and the mechanical element 13, corresponding to the three electric power lines of the U, V, and W phases, respectively.

[0028] Figure 2 The unipolar configuration of the semiconductor module 12 shown includes two semiconductor elements 121. Each semiconductor element 121 is a semiconductor switching element. Each semiconductor element 121 controls the on / off state of power supply according to the gate control signal s2 from the control unit 16. When the power supply is turned on, each semiconductor element 121 energizes the electrical circuit connecting the power supply and the load. By switching the power supply from on to off, the current in the electrical circuit is cut off.

[0029] Semiconductor element 121 has unidirectional interruption capability. Semiconductor element 121 is, for example, a metal oxide semiconductor field-effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). When semiconductor element 121 is a MOSFET, one terminal 122 is the drain terminal and the other terminal 123 is the source terminal. When semiconductor element 121 is an IGBT, one terminal 122 is the collector terminal and the other terminal 123 is the emitter terminal. Semiconductor element 121 can interrupt only the current of the polarity flowing from terminal 122 to terminal 123.

[0030] In order to enable the semiconductor module 12 to have bidirectional interruption capability, cutting off both forward and reverse currents, such as Figure 2 As shown, in semiconductor module 12, two semiconductor elements 121 are connected in series with terminals 122 of one semiconductor element 121 facing each other. Alternatively, the two semiconductor elements 121 can be connected in series with terminals 123 of one semiconductor element 121 facing each other. Diode 124 is connected in parallel with semiconductor elements 121. Diode 124 bypasses current in a direction that semiconductor elements 121 cannot cut off.

[0031] Next, based on Figure 3 The flowchart illustrates the operation of the semiconductor circuit breaker selection coordination system 100. Figure 3 This is a flowchart illustrating the operation of the semiconductor circuit breaker 1 in the semiconductor circuit breaker selection coordination system 100 according to Embodiment 1. Figure 3 This mainly illustrates the operation flow of the control unit 16 of the semiconductor circuit breaker 1. In step S101, the current measuring unit 15 measures the current value I detected by the first current sensor 14. M Measurements are performed. In step S102, the current measuring unit 15 measures the current values ​​I detected by the second current sensors 31 to 3N respectively. SW 1~I SW N is measured.

[0032] In step S103, the control unit 16 determines the current value I measured in step S101 and detected by the first current sensor 14. M Is it greater than the first threshold? The control unit 16 determines it to be the current value I. MIf the current value is greater than the first threshold (S103 is Yes), the operation proceeds to step S104, where the control unit 16 determines that the current value is I. M If the value is less than or equal to the first threshold (S103 is No), the action proceeds to step S105.

[0033] In step S104, the control unit 16 immediately disconnects the semiconductor module 12, cutting off the current. This action is performed because it is difficult to perform current limiting control on the semiconductor module 12, and cutting off the current may also become difficult. That is, in step S104, the control unit 16 immediately cuts off the current through the semiconductor module 12. Figure 3 In this context, the action of step S104 is indicated by a statement such as "semiconductor element OFF".

[0034] In step S105, the control unit 16 determines the current value I measured in step S101 and detected by the first current sensor 14. M Is it greater than the second threshold? The second threshold is less than the first threshold. The control unit 16 determines it to be the current value I. M If the current value is greater than the second threshold (S105 is Yes), the operation proceeds to step S106. The control unit 16 determines the current value to be I. M If the value is less than or equal to the second threshold (S105 is No), the action returns to step S101, and the actions from step S101 to step S103 are performed.

[0035] In step S106, the current value I detected by the first current sensor 14 is... M If the current value is greater than the second threshold and less than or equal to the first threshold, the control unit 16 causes the semiconductor module 12 to switch on and off, initiating current limiting control for the fault current. The reason for initiating current limiting control is that, due to the current value I... M The current value is greater than the second threshold, therefore some kind of accident or overcurrent has occurred, but due to the current value I... M The current is less than or equal to the first threshold, therefore current limiting control can be implemented by the semiconductor module 12. By limiting the current, the current can be interrupted by multiple switches 21 to 2N on the load side. Figure 3 In this context, the action of step S106 is indicated by a statement such as "start current limiting control through semiconductor elements".

[0036] Figure 4 This is an explanatory diagram used to illustrate the operation of the selection coordination system 100 for the semiconductor circuit breaker according to Embodiment 1. Figure 4In the example, at timing t0, the power is turned on and current begins to flow. However, a short circuit occurs in a branch circuit of load 41, causing the current flowing in load 41 to increase, and the overall current also increases. At timing t1, the control unit 16 detects the fault current, and the semiconductor circuit breaker 1 begins current limiting control to suppress the current increase.

[0037] In the next step S107, the control unit 16 measures the multiple current values ​​I detected by the multiple second current sensors 31 to 3N in step S102. SW 1~I SW N, the current value I detected by the second current sensor 31 SW 1. Sequentially determine whether it is greater than the baseline value I. 基准 The control unit 16 determines the multiple measured current values ​​I. SW 1~I SW N is greater than the baseline value I. 基准 If S107 is Yes, the operation proceeds to step S109. The control unit 16 determines that the multiple measured current values ​​I... SW 1~I SW N is less than or equal to the baseline value I 基准 In the case where S107 is No, the operation proceeds to step S108 to determine the current value I of the next branch circuit. SW If the determination is 1, proceed to step S107 again, repeating this action until the determination is I in step S107. SW 1~I SW N is greater than the baseline value I 基准 .

[0038] In step S109, the control unit 16 determines, based on the current values ​​detected by the plurality of second current sensors 31 to 3N, which indicate that an overcurrent is flowing in which branch circuit. Figure 3 In step S109, the action is indicated by a statement such as "determine the fault location of the branch circuit." In the following step S110, the control unit 16 outputs a command to open the contacts of the switches in the branch circuit determined in step S109 from among the multiple switches 21-2N that constitute the branch circuit. At this time, since the fault current is limited by the semiconductor module 12, the multiple switches 21-2N can interrupt the current. Figure 3 In this context, the action of step S110 is indicated by a statement such as "disconnect the switch of the branch circuit where the accident was detected".

[0039] Furthermore, in the subsequent step S111, since the switch of the branch where the accident occurred was set to open in step S110, the control unit 16 stops the current limiting control performed by the semiconductor module 12 and sets the semiconductor module 12 to open. Figure 3 In this context, step S111 is represented by a statement such as "Stop the current limiting control of the semiconductor device, semiconductor device ON". Using... Figure 4 The actions related to step S111 are further explained. Figure 4 At time t2, the switch is turned off, the current flowing in the load 41 is cut off, and then the control unit 16 stops the current limiting control performed by the semiconductor module 12, the semiconductor module 12 is turned on, so the current in the load 42 continues to flow.

[0040] The semiconductor circuit breaker selection coordination system 100 according to Embodiment 1 includes: a semiconductor circuit breaker 1, which switches circuit 2 on and off via a semiconductor module 12; a first current sensor 14, which measures the current flowing in the semiconductor circuit breaker 1; a plurality of switches 21 to 2N, which are connected to the load side of the semiconductor circuit breaker 1 and have opening and closing contacts; a plurality of second current sensors 31 to 3N, which measure the current flowing in each of the plurality of switches 21 to 2N; and a control unit 16, which, if the current measuring unit 15 detects an emergency current, causes the semiconductor module 12 to perform current limiting control, determines the switch from the plurality of switches 21 to 2N that is flowing with an emergency current based on the current values ​​measured by the plurality of second current sensors 31 to 3N, and after performing current limiting control, causes the switch determined to be flowing with an emergency current to disconnect. Therefore, the semiconductor circuit breaker selection coordination system 100 can use switches in branch circuits and can be used to construct a distribution panel simply and inexpensively. Alternatively, the fault current may not be detected by the current measuring unit 15, but by the first current sensor 14. Each of the multiple switches 21 to 2N may also have a semiconductor element instead of a switching contact.

[0041] In addition, since current limiting control is not always performed, the semiconductor circuit breaker 1 immediately disconnects when it is determined that current limiting control is difficult to perform. Therefore, the overall reliability of the semiconductor circuit breaker selection coordination system 100 is high.

[0042] Each of the multiple switches 21 to 2N is a circuit breaker with a low breaking capacity.

[0043] Implementation Method 2

[0044] Figure 5This diagram illustrates the structure of the selection coordination system 101 for the semiconductor circuit breaker according to Embodiment 2. In Embodiment 2, the semiconductor circuit breaker 1A has a load characteristic setting unit 17, which sets a threshold value corresponding to the load characteristics of the loads 41 to 4N, such as the magnitude of the surge current, for each branch circuit. Furthermore, the load characteristic setting unit 17 functions to input the characteristics of each load 41 to 4N connected to the load side of the plurality of switches 21 to 2N to the control unit 16. Regarding the structure other than the load characteristic setting unit 17, the structure of the selection coordination system 101 for the semiconductor circuit breaker is the same as that of the selection coordination system 100 for the semiconductor circuit breaker according to Embodiment 1. Therefore, detailed descriptions of all structural elements of the selection coordination system 101 for the semiconductor circuit breaker, except for the load characteristic setting unit 17, are omitted. Furthermore, the control unit 16 detects fault current based on the characteristics.

[0045] Next, based on Figure 6 The flowchart shown illustrates the operation of the semiconductor circuit breaker selection coordination system 101 according to Embodiment 2. Figure 6 This is a flowchart illustrating the operation of the semiconductor circuit breaker 1A in the semiconductor circuit breaker selection coordination system 101 according to Embodiment 2. Figure 6 The main illustration shows the operation flow of the control unit 16 of the semiconductor circuit breaker 1A. Steps S201 to S206 and S212 are the same as steps S101 to S106 and S111 in Embodiment 1, so detailed descriptions of steps S201 to S206 and S212 are omitted.

[0046] After current limiting control is started in step S206, in step S207, the control unit 16 sequentially sets the current threshold I for each branch circuit, which is set by the load characteristic setting unit 17, starting from the branch circuit connected to the switch 21. 基准 N.

[0047] In the next step S208, the control unit 16 determines the current value I detected by the second current sensor for the set branch circuit. SW Is N greater than the threshold I? 基准 N. Control unit 16 determines the current value I SW N is greater than the threshold I 基准 In the case of N (S208 is Yes), it is determined to be related to the current value I. SW The branch circuit corresponding to N is the branch circuit where the accident occurred, and the operation proceeds to step S210. The control unit 16 determines that the current value I... SW N is less than or equal to the threshold I 基准In the case of N (S208 is No), it is determined to be related to the current value I. SW The branch loop corresponding to N is not the branch loop where an accident occurred. The next branch loop is determined, so the action proceeds to step S209.

[0048] In step S209, the control unit 16 designates the next branch loop as the branch loop to be processed in steps S207 and S208, and the operation returns to step S207. Thus, the operations from steps S207 to S209 are repeated until the current value I is found in step S208. SW N is greater than the threshold I 基准 N's branch loop. Figure 6 In this process, the action of step S209 is represented by a statement such as "set the decision object as the next branch loop".

[0049] After finding the current value I SW N is greater than the threshold I 基准 In step S210 of the branch circuit of N, the control unit 16 determines the branch circuit as an emergency circuit. Figure 6 In this context, the action of step S210 is indicated by a statement such as "determine the fault location of the branch circuit".

[0050] In the next step S211, the control unit 16 issues a command to disconnect the switch of the branch circuit determined in step S210, and the operation proceeds to the next step S212. Figure 6 In this context, the action of step S211 is indicated by a statement such as "disconnect the switch of the branch circuit where the accident was detected".

[0051] According to Embodiment 2, the semiconductor circuit breaker 1A includes a load characteristic setting unit 17. This load characteristic setting unit 17 sets a threshold value corresponding to the load characteristics, such as the magnitude of the surge current, of the plurality of loads 41 to 4N for each branch circuit. The threshold value corresponding to the load characteristics, such as the magnitude of the surge current, can be set for each branch circuit. Since the semiconductor circuit breaker 1A outputs disconnection commands to the plurality of switches 21 to 2N on the load side, it is possible to suppress the situation where multiple disconnection commands to the switches 21 to 2N are issued due to the detection of surge current, etc.

[0052] Implementation Method 3

[0053] Figure 7This diagram illustrates the structure of the selection coordination system 102 for the semiconductor circuit breaker according to Embodiment 3. The selection coordination system 102 for the semiconductor circuit breaker does not have the plurality of second current sensors 31-3N present in the selection coordination system 100 for the semiconductor circuit breaker according to Embodiment 1. In Embodiment 3, the semiconductor circuit breaker 1B has a wire characteristic setting unit 18, which sets the inductance of the wires connecting the plurality of switches 21-2N to each load 41-4N as the characteristic of each load 41-4N connected to the load side of the plurality of switches 21-2N. The structure of the semiconductor circuit breaker 1B, except for the wire characteristic setting unit 18, is the same as that of the semiconductor circuit breaker 1 in Embodiment 1. Figure 7 The diagram shows multiple resistors ranging from 51 to 5N and multiple inductors ranging from 61 to 6N. The corresponding resistors and inductors schematically illustrate the electrical structure of the wires.

[0054] Figure 8 This is to explain the difference between wire specifications and wire specifications. Figure 7 The method for estimating the current in each branch circuit is shown, and a diagram illustrating the state of the electrical circuit when semiconductor circuit breaker 1B operates is presented. (See diagram for example.) Figure 8 As shown, when the semiconductor circuit breaker 1B operates, a voltage V is applied across the semiconductor circuit breaker 1B. The control unit 16 measures the voltage V. The power supply voltage E of the electrical circuit 11 is also measured in real time, and the value of the power supply voltage E is input to the control unit 16. The value of the current flowing in each branch circuit is the current value I. M The current value I is measured by the first current sensor 14 of the semiconductor circuit breaker 1B. M Input to control unit 16. Figure 8 In the diagram, semiconductor circuit breaker 1B is shown as "SSCB1B", and "I, I1, I2, I N This means the current flowing in the corresponding wire.

[0055] according to Figure 8 The equation of the electrical circuit is expressed by the following equation (1).

[0056]

[0057] If we assume that dI / dt of the branch circuit without an accident can be neglected and transform equation (1), then the inductance L of the branch circuit with an accident... 事故 This is expressed by the following formula (2).

[0058]

[0059] Furthermore, if the current is limited by the semiconductor module 12, the ΣR generated by the resistance value... N IN If it can be ignored, then the inductance L 事故 This is expressed by the following equation (3).

[0060]

[0061] The inductance L is calculated by inputting the measured power supply voltage E, voltage V, and dI / dt values ​​into equation (3). 事故 .

[0062] On the other hand, the wire characteristic setting unit 18 can calculate the inductance L of each branch circuit by setting the wire diameter, conductor center distance, and wire length of the wires connected to each load. N The scenario here is a short circuit on the load side; therefore, the conductor center-to-center distance represents the distance between the center-to-center distances of the conductors of the wires that form the current path in the circuit where the short circuit occurred.

[0063] Therefore, the control unit 16 calculates the inductance L of each branch circuit. N In the middle, the inductance L calculated according to equation (3) is selected. 事故 The closest inductor is used to presume the branch circuit corresponding to that inductor as the fault circuit, and the switch of that circuit is set to open. The inductance L of each branch circuit... N It is calculated based on the wire diameter, conductor center distance, and wire length of the wires connected to each switch, as set by the wire characteristic setting unit 18.

[0064] In addition, regarding the inductance L of each branch circuit N In addition to the method described above, which calculates the inductance based on the wire diameter, conductor center distance, and wire length of the wires connected to each load, the inductance can also be directly input into the wire characteristic setting unit 18 based on the type and length of the wire. Alternatively, the inductance per unit length for each wire type recorded in wire manuals or similar documents can be stored in the wire characteristic setting unit 18 beforehand, and the calculation can be performed by inputting the wire type and wire length. The unit of the inductance per unit length is mH / km, and the value of this inductance is, for example, 0.1 to 0.3 mH / km.

[0065] After setting the switch to open, the control unit 16 again determines whether the fault current has been cut off 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 cut off, it selects the inductance L obtained by formula (3). 事故The second closest inductor sets the switch of the circuit corresponding to the selected inductor to open. The control unit 16 then determines whether the fault current has been cut off based on the dI / dt measured by the first current sensor 14. The control unit 16 cuts off the fault circuit by repeating the above operation.

[0066] Next, based on Figure 9 The flowchart shown illustrates the operation of the semiconductor circuit breaker selection coordination system 102. Figure 9 This is a flowchart illustrating the operation of the semiconductor circuit breaker 1B in the semiconductor circuit breaker selection coordination system 102 according to Embodiment 3. Figure 9 This mainly illustrates the operation flow of the control unit 16 of the semiconductor circuit breaker 1B. In step S301, the control unit 16 calculates the inductance L1 to L2 of the wires in each branch circuit based on the wire diameter and length of the wires connected to each load, as set by the wire characteristic setting unit 18. N That is, in step S301, the control unit 16 calculates the inductance of each branch circuit according to the wire specifications.

[0067] Steps S302 to S307 are the same as steps S101, S103 to S106 and S111 in Embodiment 1, therefore detailed descriptions of steps S302 to S307 are omitted.

[0068] The control unit 16 uses the current value I measured by the first current sensor 14. M If the current value is greater than the first threshold (S303 is Yes), the semiconductor module 12 is disconnected, and the current value I... M If the current limiting control is less than or equal to the first threshold and greater than the second threshold (S303 is No, S305 is Yes), after the current limiting control is started in step S306, the inductance estimation process 300 of the fault branch circuit is performed.

[0069] Regarding the inductance estimation of the fault branch circuit 300, use... Figure 10 Please provide an explanation. Figure 10 It means Figure 9 The flowchart shows the operation process of the inductance estimation processing 300 for the faulty branch circuit. In step S311, the control unit 16 estimates the inductance L of the faulty branch circuit based on equation (3). 事故 Perform the calculation.

[0070] In step S312, the control unit 16 calculates the inductance L1 to L2 of the wires in each branch circuit from step S301. N In the process, the inductance L calculated through step S311 is extracted. 事故 The inductance value closest to the given value. Figure 10In step 312, the action is performed by "selecting and L". 事故 Approaching L N Such statements indicate...

[0071] In step S313, the control unit 16 sets the switch in the branch circuit of the inductor extracted in step S312 to be open. Figure 10 In step 313, the action is performed by "selecting L". N The statement indicates that "the corresponding branch circuit's switch is disconnected." In step S314, in order to confirm whether the switch set to disconnected is indeed the branch circuit where an accident has occurred, the control unit 16 bases its statement on... Figure 11 The current waveform shown is used to measure dI / dt when semiconductor module 12 is turned on. Figure 11 This is a diagram showing the current waveform of the semiconductor circuit breaker 1B in the semiconductor circuit breaker selection coordination system 102 according to Embodiment 3 when it performs current limiting operation. Figure 11 The difference between t2 and t1, i.e., Δt, means dI / dt in dt, and the difference between c1 and c2 means dI.

[0072] In step S315, the control unit 16 determines whether the dI / dt measured in step S314 is less than the third threshold. If the control unit 16 determines that dI / dt is less than the third threshold (S315 is Yes), the switch is set to open in step S313, thereby confirming that the fault circuit is cut off, and the inductance estimation process 300 of the fault branch circuit ends. Operation enters... Figure 9 Step S307.

[0073] On the other hand, if the control unit 16 determines that dI / dt is greater than or equal to the third threshold (S315 is No), the switch is set to open in step S313. However, since it is determined that the fault circuit has not been cut off, the operation proceeds to step S316. In step S316, the control unit 16 sets the switch, which was set to open in step S313, back to closed. Figure 10 In step 316, the action is performed by "transferring L". N The statement "the corresponding branch circuit switch is closed" indicates this.

[0074] In step S317, the control unit 16 extracts the data related to the inductor L in the subsequent step, namely step S312. 事故 Before finding the closest inductance value, calculate the inductance L1 to L2 of the wires in each branch circuit from step S301. N In this process, the inductance of the branch circuit that disconnects the switch in step S313 is excluded from the selected object. Figure 10 In step 317, the action is performed by "selecting L".N The statement "Excluded from selected objects" indicates that the action returns from step S317 to step S312, and the control unit 16 performs the actions from step S312 to step S315.

[0075] The semiconductor circuit breaker selection and coordination system 102 according to Embodiment 3 includes: a semiconductor circuit breaker 1B, which switches the circuit 2 on and off via a semiconductor module 12; a first current sensor 14, which measures the current flowing in the semiconductor circuit breaker 1B; a plurality of switches 21 to 2N, which are connected to the load side of the semiconductor circuit breaker 1B and have opening and closing contacts; a wire characteristic setting unit 18, which sets the wire diameter and wire length of the wires connecting the plurality of switches 21 to 2N and each load 41 to 4N as the characteristics of the wires, as the characteristics of each load 41 to 4N connected to the load side of the plurality of switches 21 to 2N; and a control unit 16, which, if the first current sensor 14 detects an emergency current, causes the semiconductor module 12 to perform current limiting control, selects the switch from the plurality of switches 21 to 2N that is flowing with the emergency current based on the emergency current, wire diameter, and wire length, and causes the switch to open after performing current limiting control. Therefore, switchgear can be used in branch circuits, and distribution panels can be constructed simply and inexpensively.

[0076] Furthermore, even without a current sensor that measures the current of each of the multiple switches 21 to 2N, the semiconductor circuit breaker selection coordination system 102 can determine the branch circuit where the accident occurred, thus enabling the distribution panel to be constructed simply and inexpensively.

[0077] Furthermore, even if the branch circuit selected by the inductance estimation process 300 for the fault branch circuit is not a fault circuit, the semiconductor circuit breaker selection coordination system 102 will measure the dI / dt when the semiconductor module 12 is turned on after setting the switch to open to confirm whether the selected branch circuit is indeed a faulty branch circuit. If the wrong branch circuit is selected, the next branch circuit is selected and the dI / dt when the semiconductor module 12 is turned on is checked again. Therefore, the fault circuit can be reliably disconnected.

[0078] Figure 12This diagram illustrates a processor 91 in the case where some or all of the functions of the current measurement unit 15 and control unit 16 in the semiconductor circuit breaker selection coordination system 100 according to Embodiment 1 are implemented by a processor 91. That is, some or all of the functions of the current measurement unit 15 and control unit 16 can be implemented by the processor 91, which executes programs stored in the memory 92. The processor 91 is a CPU (Central Processing Unit), processing system, arithmetic system, microprocessor, or DSP (Digital Signal Processor). Figure 12 The memory 92 is also shown.

[0079] When some or all of the functions of the current measuring unit 15 and the control unit 16 are implemented by the processor 91, these functions are implemented by the processor 91 in conjunction with software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. The processor 91 implements some or all of the functions of the current measuring unit 15 and the control unit 16 by reading and executing the program stored in the memory 92.

[0080] When some or all of the functions of the current measuring unit 15 and the control unit 16 are implemented by the processor 91, the semiconductor circuit breaker selection coordination system 100 has a memory 92 for storing programs that enable some or all of the steps performed by the current measuring unit 15 and the control unit 16 to be ultimately executed. The program stored in the memory 92 can also be described as part or all of the process or method executed by the current measuring unit 15 and the control unit 16 that enables the computer to execute.

[0081] The memory 92 includes, for example, non-volatile or volatile semiconductor memories 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), disks, floppy disks, optical disks, compact disks, mini disks, or DVDs (Digital Versatile Disk).

[0082] Figure 13This diagram illustrates the processing circuit 93 in the case where some or all of the functions of the current measurement unit 15 and the control unit 16 of the semiconductor circuit breaker selection coordination system 100 according to Embodiment 1 are implemented by the processing circuit 93. That is, some or all of the functions of the current measurement unit 15 and the control unit 16 can be implemented by the processing circuit 93.

[0083] The processing circuit 93 is dedicated hardware. The processing circuit 93 may be, for example, a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0084] Some of the functions of the current measurement unit 15 and the control unit 16 can also be implemented by other dedicated hardware that is different from the hardware that implements the remaining functions of the current measurement unit 15 and the control unit 16.

[0085] Regarding the multiple functions of the current measuring unit 15 and the control unit 16, some of these functions may be implemented using software or firmware, while the remaining functions may be implemented using dedicated hardware. As described above, the multiple functions of the current measuring unit 15 and the control unit 16 can be implemented using hardware, software, firmware, or a combination thereof.

[0086] In Embodiment 2, 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 can be implemented by a processor or by a processing circuit. The processor is the same as processor 91. The processing circuit is the same as processing circuit 93.

[0087] In Embodiment 3, some or all of the functions of the current measurement unit 15, control unit 16, and wire characteristic setting unit 18 in the semiconductor circuit breaker selection coordination system 102 can be implemented by a processor or by a processing circuit. The processor is the same as processor 91. The processing circuit is the same as processing circuit 93.

[0088] The structure shown in the above embodiments is an example and can be combined with other known technologies. The embodiments can also be combined with each other, and parts of the structure can be omitted or changed without departing from the spirit of the subject.

[0089] Explanation of the label

[0090] 1. Semiconductor circuit breaker, 1A, 1B; 2. Circuit; 11. Electrical circuit; 12. Semiconductor module; 13. Mechanical component; 14. First current sensor; 15. Current measurement unit; 16. Control unit; 17. Load characteristic setting unit; 18. Wire characteristic setting unit; 21-2N. Switch; 31-3N. Second current sensor; 41-4N. Load; 51-5N. Resistor; 61-6N. Inductor; 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 processing for fault branch circuit.

Claims

1. A selection coordination system for semiconductor circuit breakers, characterized in that, have: A semiconductor circuit breaker uses semiconductor elements to switch circuits on and off. The first current sensor measures the current flowing in the semiconductor circuit breaker; Multiple switches are connected to the load side of the semiconductor circuit breaker; Multiple second current sensors, which measure the current flowing in each of the multiple switches; as well as If an emergency current is detected by the first current sensor, the control unit causes the semiconductor element to perform current limiting control. Based on the current measured by the plurality of second current sensors, the control unit determines from the plurality of switches that are flowing with the emergency current, and after performing the current limiting control, causes the switch to disconnect. Each of the plurality of switches has an opening / closing contact or a semiconductor element.

2. The selection and coordination system for semiconductor circuit breakers according to claim 1, characterized in that, It also includes a load characteristic setting unit, which inputs the characteristics of each load connected to the load side of the plurality of switches to the control unit. The control unit detects the fault current based on the aforementioned characteristics.

3. The selection and coordination system for semiconductor circuit breakers according to claim 2, characterized in that, The characteristic mentioned is the magnitude of the surge current.

4. A selection coordination system for semiconductor circuit breakers, characterized in that, have: A semiconductor circuit breaker uses semiconductor elements to switch circuits on and off. The first current sensor measures the current flowing in the semiconductor circuit breaker; Multiple switches, which are connected to the load side of the semiconductor circuit breaker, have opening and closing contacts; The wire characteristic setting unit sets the characteristics of the wires connecting the plurality of switches to each load as the characteristics of each load connected to the load side of the plurality of switches. as well as If an emergency current is detected by the first current sensor, the control unit causes the semiconductor element to perform current limiting control. Based on the emergency current, the diameter of the wire, and the length of the wire, the control unit selects the switch from the plurality of switches that carries the emergency current, and causes the switch to disconnect after performing the current limiting control.

5. The selection coordination system for semiconductor circuit breakers according to any one of claims 1 to 4, characterized in that, Each of the multiple switches is a circuit breaker with a low breaking capacity.

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