Switching device and control method for switching device

Abstract

In the present invention, a switch unit (20) is connected between a first node (N1) that is electrically connected with a power supply, and a second node (N2) that is electrically connected with a load circuit that receives a supply of power from the power supply. As a current suppression element (30), an electrical resistor (31) for current limiting is connected in parallel with the switch unit (20). An accident detection unit (40) detects abnormalities within an energized circuit formed by electrically connecting between the first node and the second node (N2). An open / close command unit (25) executes an abnormality diagnosis on the basis of output of the accident detection unit (40) in a first state with the switch unit (20) controlled so that the impedance between the first node (N1) and the second node (N2) is a first value during the closing operation of a switching device (10c), and when an abnormal state is not detected in that abnormality diagnosis, controls the switch unit (20) so that a second state is formed in which the impedance is equal to or less than the first value.

Description

[Technical field]

[0001] The present disclosure relates to a switching device and a control method for the switching device. [Background technology]

[0002] Electrical contacts, semiconductor switches, etc. are used as switching elements for closing and opening an electric circuit. Japanese Utility Model Application Publication No. 5-78146 (Patent Document 1) discloses a current-limiting circuit breaker in which a semiconductor switch and a current-limiting resistor are each connected in parallel with a high-speed switch in a configuration in which a high-speed switch and a circuit breaker are connected in series.

[0003] According to the current-limiting circuit breaker of Patent Document 1, under normal circumstances, a large current is passed through a high-speed switch composed of mechanical contacts, but when a short-circuit accident occurs and an abnormality is detected by a current transformer, the semiconductor switch is turned on and then the mechanical contacts are opened, so that the short-circuit current is diverted to the semiconductor switch, and the arc is quickly extinguished.

[0004] Furthermore, after the commutation to the semiconductor switch is completed, the short-circuit current can be further commutated to the current-limiting resistor without arcing by turning off the semiconductor switch. As a result, the current-limiting breaker of Patent Document 1 can quickly extinguish the arc and safely open the electric circuit without requiring a special commutation mechanism. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 5-78146 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, the current-limiting circuit breaker of Patent Document 1 can realize a safe circuit when a short circuit occurs in the electric circuit from a normal closed state. On the other hand, when a switchgear is used to connect a power source and an electric circuit, that is, when a circuit to be connected is closed during a closing operation from an open state to a closed state, if an abnormality such as a short circuit has already occurred in the circuit, a large current is generated at the same time as the circuit is closed, and there is a concern that the switching element may be damaged. However, Patent Document 1 does not particularly describe control during the closing operation.

[0007] On the other hand, in order to ensure resistance to the above-mentioned case where a short circuit current occurs simultaneously with the closing of the circuit, measures can be considered such as increasing the current carrying capacity of the switchgear and semiconductor switch, or arranging multiple switches in parallel and increasing the breaking capacity or closing capacity of the circuit breaker. However, there is a concern that such measures will lead to an increase in the size and cost of the switchgear.

[0008] The present disclosure has been made to solve such problems, and an object of the present disclosure is to provide a switching device and a control method for a switching device that are capable of preventing the generation of excessive current and damage to components during closing operation even when a circuit in which an abnormality such as a short circuit has occurred is closed. [Means for solving the problem]

[0009] According to an aspect of the present disclosure, there is provided a switchgear. The switchgear includes a switch unit, a current suppression element, and a switching command unit that controls the opening and closing of the switch unit. The switch unit is connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit that receives power from the power source. The current suppression element is connected in parallel with the switch unit between the first node and the second node. The accident detection unit detects an abnormality in a current-carrying circuit including a power source and a load circuit formed by electrically connecting the first node and the second node. The switching command unit controls the switch unit so that a first state is formed in which an impedance between the first node and the second node has a first value during a closing operation of the switchgear, and performs an abnormality diagnosis based on an output of the accident detection unit. When an abnormal state is not detected by the accident detection unit in the abnormality diagnosis, the switching command unit controls the switch unit so that a second state is formed in which the impedance has a second value that is equal to or less than the first value.

[0010] According to another aspect of the present disclosure, there is provided a control method for a switchgear, the control method for a switchgear being disposed between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source, includes the steps of: controlling, during a closing operation of the switchgear, a switch unit connected in parallel with a current suppressing element between the first node and the second node to form a first state in which an impedance between the first node and the second node is a first value; executing, in the first state, an abnormality diagnosis for detecting an abnormal state in a current-carrying circuit including the power source and the load circuit formed by electrically connecting the first node and the second node; controlling the switch unit so as to form a second state in which the impedance is a second value equal to or less than the first value when the abnormality diagnosis does not detect the abnormality; and opening the switch unit when the abnormality diagnosis detects the abnormality. Effect of the Invention

[0011] According to the present disclosure, the switch unit is controlled so that a steady closed-circuit state is established between the first node and the second node only when the abnormality diagnosis is normal in a state (first state) in which the impedance between the first node and the second node is higher than a steady closed-circuit state (second state). Therefore, even when a circuit in which an abnormality such as a short circuit has occurred is closed, the generation of excessive current and damage to components can be prevented. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a conceptual circuit diagram illustrating a configuration example of a switching device according to a first embodiment. [Diagram 2] FIG. 4 is a waveform diagram illustrating a control operation in a closing operation of the switching device according to the first embodiment. [Diagram 3] 4 is a flowchart illustrating a first example of a control process during a closing operation of the switching device according to the first embodiment. [Figure 4] 10 is a flowchart illustrating a second example of a control process during a closing operation of the switching device according to the first embodiment. [Diagram 5] 13 is a cross-sectional view illustrating a modified example of the commutation switch. FIG. [Figure 6] FIG. 4 is a conceptual circuit diagram illustrating a configuration example of a switching device according to a modified example of the first embodiment. [Figure 7] FIG. 11 is a conceptual circuit diagram illustrating a configuration example of a switching device according to a second embodiment. [Figure 8] 10 is a flowchart illustrating an example of a control process during a closing operation of a switching device according to the second embodiment. [Figure 9A] 13 is a conceptual cross-sectional view illustrating the configuration of a switching command unit according to embodiment 3 and its operation during low current. FIG. [Figure 9B] 13 is a conceptual cross-sectional view illustrating the configuration of a switching command unit according to embodiment 3 and its operation within a reference current range. FIG. [Figure 9C] 11 is a conceptual cross-sectional view illustrating the configuration of a switching command unit according to embodiment 3 and its operation during an overcurrent. FIG. [Figure 10]FIG. 13 is a conceptual circuit diagram illustrating a configuration example of a switching device according to a fourth embodiment. [Figure 11] FIG. 13 is a conceptual circuit diagram illustrating a configuration example of a switching device according to a fifth embodiment. [Figure 12] 13 is a flowchart illustrating an example of a control process during a closing operation of a switching device according to embodiment 5. [Figure 13] 13 is an example of an operational waveform diagram of a semiconductor switch in a switching device according to embodiment 5. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference characters, and their description will not be repeated in principle.

[0014] Embodiment 1 FIG. 1 is a conceptual circuit diagram illustrating a configuration example of a switching device 10a according to the first embodiment.

[0015] 1, a switching device 10a includes a switch section 20, a switching command section 25, an electric resistor 31 serving as a current suppressing element 30, a fault detection section 40, and a current switching section 50. The switching device 10a includes a switch section 20, a switching command section 25, an electric resistor 31 serving as a current suppressing element 30, an accident detection section 40, and a current switching section 50.

[0016] The switch section 20 and the current switching section 50 are connected in series between the nodes N1 and N2, and control the connection state between the nodes N1 and N2 according to a command from the switching command section 25.

[0017] The node N1 is electrically connected to a power supply (not shown). The node N2 is electrically connected to a load circuit (not shown) that receives power from the power supply. That is, in the first embodiment, the current switching unit 50 is connected between the switch unit 20 and the node N2. The nodes N1 and N2 correspond to an example of a "first node" and a "second node", respectively.

[0018] The switch section 20 includes an electrical contact 21 and a commutation switch 22 connected in parallel. Each of the electrical contact 21 and the commutation switch 22 is opened or closed by a switching command section 25. The switching command section 25 can be configured, for example, by a microcomputer having a program implemented for executing the control processing described below.

[0019] The electrical contacts 21 are arranged to form a steady current path and are therefore configured with low impedance. For example, the electrical contacts 21 are configured to be opened and closed mechanically depending on the presence or absence of electromagnetic force. The commutation switching unit 22 is arranged to operate in the event of an accident and is typically configured with a semiconductor switch. As will be explained later as a modified example, the commutation switching unit 22 can also be configured with contacts.

[0020] The electrical contacts 21 have a current carrying capacity corresponding to the power supply to a load circuit (not shown), but basically do not require a breaking capacity. In contrast, the commutation switch 22 is configured to have a smaller current carrying capacity but a larger breaking capacity than the electrical contacts 21. Furthermore, the impedance of the electrical contacts 21 in the on state is equal to or less than the impedance of the commutation switch 22 in the on state.

[0021] The current switching unit 50 is composed of a circuit breaker or a switch capable of interrupting a fault current. The current switching unit 50 requires a current-carrying capacity equivalent to that of the electrical contacts 21. Generally, a switch has the ability to interrupt an overcurrent that is several times to less than ten times the rated current, and a circuit breaker has the ability to interrupt a short-circuit current that is ten times or more the rated current. Therefore, the circuit breaker or switch can be selected as the current switching unit 50 according to the magnitude of the fault current that is expected to be interrupted.

[0022] The accident detection unit 40 detects an abnormality in a current-carrying circuit formed by electrically connecting the nodes N1 and N2 and including a power supply (not shown) connected to the node N1 and a load circuit (not shown) electrically connected to the node N2. An abnormality diagnosis is performed based on the output of the accident detection unit 40, i.e., whether or not an abnormal state is detected.

[0023] The accident detection unit 40 detects the occurrence of an abnormal state (accident) represented by an overcurrent caused by a short circuit based on an electrical signal reflecting measurement information such as current, voltage, electrical resistance calculated from the ratio of current and voltage, or temperature rise at a predetermined portion in the current-carrying circuit. Alternatively, the accident detection unit 40 can detect the occurrence of an abnormal state based on the distribution (frequency spectrum) of frequency components of the electrical signal.

[0024] When an abnormality occurs in the circuit, a change in the circuit characteristics occurs, such as an increase in current, and the accident detection unit 40 can detect the abnormal state by measuring the change in current. Also, when a short circuit occurs, a drop in voltage or a drop in electrical resistance occurs at the shorted location. Therefore, the accident detection unit 40 can also detect an abnormal state by measuring the voltage or electrical resistance.

[0025] Alternatively, abnormal heat may be generated within the current-carrying circuit, and the accident detection unit 40 can also detect the abnormal state by measuring the temperature rise. Furthermore, when an abnormality accompanied by discharge occurs, a phenomenon occurs in which discharge noise is superimposed on the above-mentioned electrical signal, or light is emitted in association with the discharge. Therefore, the accident detection unit 40 can also detect an abnormality by measuring the frequency component of the above-mentioned electrical signal, or the light information related to the light emission.

[0026] The light information may typically be the intensity value of light emission measured by an image sensor, or, in order to avoid false detection, the intensity value of light at a specific wavelength obtained through an optical filter or a spectroscope may be used as the light information.

[0027] The accident detection unit 40 can also detect an abnormal state by combining multiple pieces of the above-mentioned measurement information. In this case, it is possible to improve the detection accuracy and also to determine the type of abnormality.

[0028] The accident detection unit 40 can detect an abnormal state by comparing the electrical signal, the specific frequency component of the electrical signal, and the optical information with a preset reference range. Alternatively, the reference range can be set based on measurement information learned during normal operation.

[0029] Typically, the measurement information of the electrical signals etc. in a normal state is collected as normal values, and a reference range used for abnormality diagnosis can be set by statistical processing according to the distribution of the normal values. For example, a 3σ range of the collected normal values ​​is set as a reference range, and an abnormal state can be detected when the measurement information of the electrical signals etc. falls outside the reference range.

[0030] Alternatively, when detecting an abnormal condition using multiple types of measurement information, the pattern or range of the distribution (two-dimensional, three-dimensional, or four or more dimensions) of normal values ​​collected as described above is learned, and an abnormal condition can be detected when the correlation coefficient of the data pattern between the measurement information (actual values) obtained during abnormality diagnosis and the normal values ​​(learned values) becomes equal to or less than a predetermined reference value.

[0031] By setting the reference range through such learning, it becomes possible to appropriately correct the reference range even when the load circuit is updated.

[0032] FIG. 2 is a waveform diagram illustrating a control operation when the switching device 10a according to the first embodiment transitions from an open circuit state to a closed circuit state, that is, during a closing operation.

[0033] 2, at time t1, the switching device 10a is in a state in which the electrical contacts 21, the commutation switching unit 22, and the current switching unit 50 are all turned off. When the switching command unit 25 instructs the switching device 10a to perform a closing operation, it first keeps the electrical contacts 21 and the commutation switching unit 22 turned off while turning on the current switching unit 50 at time t2. As a result, in FIG. 1, a current path passing through the electrical resistance 31 and the current switching unit 50 is formed between the nodes N1 and N2. In this state, at time t3, an abnormality diagnosis A based on the output of the accident detection unit 40 is performed.

[0034] If no abnormal state is detected in abnormality diagnosis A, at time t4, switching command unit 25 keeps electrical contact 21 off while further turning on commutation switching unit 22. In this state, at time t5, abnormality diagnosis B based on the output of accident detection unit 40 is performed. If no abnormal state is detected in abnormality diagnosis B, switching command unit 25 further turns on electrical contact 21 at time t6.

[0035] Furthermore, at time t7, the switching command unit 25 may turn off the commutation switching unit 22 while keeping the electrical contact 21 on. For example, when the commutation switching unit 22 is configured by a semiconductor switch, it is preferable to turn off the commutation switching unit 22 at time t7. In a steady closed state after a normal closing operation, a current path is formed between the nodes N1 and N2 by the low-impedance electrical contact 21 and the current switching unit 50 in the on state. On the other hand, when the commutation switching unit 22 is configured as a contact, that is, includes electrical contacts, the commutation switching unit 22 may be kept on after time t7. Also, even when the commutation switching unit 22 is configured by a semiconductor switch, it is possible to keep the commutation switching unit 22 on at time t7. In either case, in a steady closed state, a current path is formed between the nodes N1 and N2 with the electrical contact 21 on. When an overcurrent occurs from the steady closed state, the fault current can be interrupted by opening the current switching unit 50.

[0036] Fig. 3 is a flowchart for explaining a control process for the circuit closing operation shown in Fig. 2. The control process shown in Fig. 3 is executed by, for example, the opening and closing command unit 25 when a circuit closing operation is commanded to the switching device 10a.

[0037] 3, in step (hereinafter simply referred to as "S") 110, the switching command unit 25 turns on the current switching unit 50. The processing of S110 is performed at time t2 in FIG. 2. As a result, in the switching device 10a (FIG. 1), a current path is formed between nodes N1 and N2 via the current switching unit 50 in the on state and the electrical resistance 31. As a result, a "first state" is formed between nodes N1 and N2. That is, in the control processing of FIG. 3, the "first value" of the impedance between nodes N1 and N2 corresponds to the sum of the on resistance of the current switching unit 50 and the electrical resistance 31.

[0038] From this state, the switching command unit 25 executes abnormality diagnosis A in S120, similarly to time t3 in Fig. 2. That is, in S120, it is determined whether or not an abnormal state is detected based on the output of the accident detection unit 40. If an abnormal state is detected, the process proceeds to S180, and the current switching unit 50, which was turned on in S110, is turned off. At this time, since the current passing through the current switching unit 50 is limited by the electrical resistance 31, the current can be easily interrupted. Then, since an abnormal state has occurred, the closing operation is terminated with the current switching unit 50, and the electrical contacts 21 and the commutation switching unit 22 constituting the switch unit 20, turned off.

[0039] On the other hand, when no abnormal state is detected in the determination in S120 (abnormality diagnosis A), in S130, switching command unit 25 maintains electrical contact 21 in the OFF state while turning on commutation switching unit 22, similar to time t4 in Fig. 2. As a result, in switching device 10a (Fig. 1), the ON resistance of commutation switching unit 22 is significantly lower than the resistance value of electrical resistance 31, so that a current path is formed between nodes N1 and N2 via current switching unit 50 and commutation switching unit 22 in the ON state.

[0040] From this state, the switching command unit 25 executes the abnormality diagnosis B in S140, similarly to time t5 in FIG. 2. In S140, it is also determined whether or not an abnormal state is detected based on the output of the accident detection unit 40. If an abnormal state is detected, the process proceeds to S170 and S180. In S170, the switching command unit 25 turns off the commutation switching unit 22 that was turned on in S130, and in S180, as described above, turns off the current switching unit 50 that was turned on in S110. As a result, when an abnormality occurs, the closing operation is terminated with the current switching unit 50 and the electrical contacts 21 and commutation switching unit 22 that constitute the switch unit 20 in the off state. The processes of S170 and S180 may be executed simultaneously, or S180 may be executed first.

[0041] Depending on the type of accident in the current-carrying circuit, in cases where the accident current passes through electrical resistance 31, the change in information detected by accident detection unit 40 may be small. In abnormality diagnosis B in which commutation switching unit 22 is turned on, the effect of electrical resistance 31 on the accident current is small, making it possible to detect abnormalities that could not be detected in abnormality diagnosis A. In particular, when commutation switching unit 22 is configured as a semiconductor switch, it is possible to perform a turn-off operation before the current rises significantly, so that the current-carrying circuit can be opened without generating an arc even when an abnormality occurs.

[0042] On the other hand, if no abnormal state is detected in the determination in S140 (abnormality diagnosis B), the switching command unit 25 further turns on the electrical contacts 21 in S150, similar to time t6 in Fig. 2. Thereafter, the switching command unit 25 turns off the commutation switching unit 22 in S160, similar to time t7 in Fig. 2. As a result, in the switching device 10a, in a steady closed circuit state after the closing operation, the electrical contacts 21 and the current switching unit 50 can form a low impedance current path between the nodes N1 and N2. As described above, the process of S160 for turning off the commutation switching unit may be omitted.

[0043] In this manner, if no abnormal state is detected by abnormality diagnosis A and abnormality diagnosis B, a "second state" is formed between nodes N1 and N2. That is, in the control process of FIG. 3, the "second value" of the impedance between nodes N1 and N2 corresponds to the sum of the on-resistance value of the current switching unit 50 and the on-resistance value of the electrical contact 21, or the resistance value of the parallel connection of the on-resistance of the electrical contact 21 and the commutation switching unit 22. That is, in the second state, the impedance between nodes N1 and N2 is equal to or lower than the impedance in the first state. Also, in the second state, the on / off state of the components of the switch unit 20 changes from the first state.

[0044] In the first embodiment, since the current switching section 50 is provided, it is also possible to configure the switch section 20 with only one of the electrical contact 21 and the commutation switching section 22.

[0045] Fig. 4 is a flowchart for explaining the control process of the closing operation when the switch section 20 is composed of only one of the electrical contacts 21 and the commutation switching section 22. The control process shown in Fig. 4 is also executed by, for example, the switching command section 25 when a closing operation is commanded to the switching device 10a.

[0046] 4, the switching command unit 25 turns on the current switching unit 50 in S110 similar to that in Fig. 3, and then executes an abnormality diagnosis A based on the output of the accident detection unit 40 in S120 similar to that in Fig. 3. If an abnormal state is detected in the abnormality diagnosis A, the process proceeds to S180. In S180, the current switching unit 50 that was turned on in S110 is turned off, thereby interrupting the fault current limited by the electrical resistance 31, and the closing operation is terminated in a state in which both the current switching unit 50 and the electrical contacts 21 or the commutation switching unit 22 that constitutes the switch unit 20 are turned off.

[0047] 4, a "first state" is created between nodes N1 and N2 by turning on current switching unit 50. That is, a "first value" of the impedance between nodes N1 and N2 corresponds to the sum of the on-resistance of current switching unit 50 and electrical resistance 31.

[0048] On the other hand, when no abnormal state is detected in the determination in S120 (abnormality diagnosis A), the switching command unit 25 turns on the electrical contacts 21 or the commutation switching unit 22 constituting the switch unit 20 in S132. As a result, in the switching device 10a (FIG. 1), a current path is formed between the nodes N1 and N2 via the current switching unit 50 and the switch unit 20 (electrical contacts 21 or commutation switching unit 22) in the on state.

[0049] From this state, the switching command unit 25 executes an abnormality diagnosis B based on the output of the accident detection unit 40 in S140 similar to that in FIG. 3, and if an abnormal state is detected, the process proceeds to S172 and S180. In S172, the switching command unit 25 turns off the electrical contacts 21 or the commutation switching unit 22 (i.e., the switch unit 20) that were turned on in S132, and in S180, as described above, turns off the current switching unit 50 that was turned on in S110. As a result, when an abnormality occurs, the closing operation is terminated with both the current switching unit 50 and the switch unit 20 turned off. As in FIG. 2, the processes of S170 and S180 may be executed simultaneously, or S180 may be executed first. Note that, when the switch unit 20 is composed of only the electrical contacts 21, it is preferable to execute S180 first and turn off the current switching unit 50 before the electrical contacts 21 from the viewpoint of preventing the generation of an arc.

[0050] When no abnormal state is detected in the determination in S140 (abnormality diagnosis B), the switching command unit 25 maintains the state in abnormality diagnosis B, i.e., the state in which the current switching unit 50 and the switch unit 20 (electrical contacts 21 or commutation switching unit 22) are turned on. As a result, the switching device 10a forms a steady closed-circuit state after the closing operation. This forms a "second state" between the nodes N1 and N2. That is, the "second value" of the impedance between the nodes N1 and N2 corresponds to the sum of the on-resistance of the current switching unit 50 and the on-resistance of the switch unit 20 (electrical contacts 21 or commutation switching unit 22).

[0051] In this way, in the switching device according to the present embodiment, during a closing operation, an abnormality diagnosis is performed while controlling the multiple switching elements so that the impedance between the nodes N1 and N2 is higher than in a steady closed state, and when no abnormality is detected in the abnormality diagnosis, the multiple switching elements are controlled so that a steady closed state is formed by the multiple switching elements. This makes it possible to prevent the generation of an excessive current and damage to components even when a circuit in which an abnormality such as a short circuit has occurred is closed.

[0052] In particular, in the switching device 10a according to embodiment 1, a current limiting effect can be obtained by first forming a path via the electrical resistance 31. Therefore, even when an electrical circuit in which an abnormality such as a short circuit has occurred is closed, the current switching unit 50 can open the circuit in response to the detection of the abnormal state without generating an excessive current.

[0053] Furthermore, in a configuration including electrical contacts 21 and commutation switching unit 22 connected in parallel to switch unit 20, by controlling the opening and closing of electrical contacts 21 and commutation switching unit 22 according to the sequence shown in FIG. 2, the interrupting capacity of commutation switching unit 22 can be utilized in abnormality diagnosis using switch unit 20 (abnormality diagnosis B), and the low impedance characteristics of electrical contacts 21 can be utilized in a steady closed circuit state.

[0054] Depending on the type of load circuit, an abnormal state may be detected only at startup, i.e., only for a certain period immediately after the electric circuit is closed, and the abnormal state may be detected only for a certain period. For example, when a load whose impedance or reactance varies after startup of a motor or the like is connected to a power source by a switching device, there may be a case where a large starting current flows only immediately after the circuit is closed. In order to deal with such a case, for the abnormality diagnosis A (S120 in Figs. 3 and 4), it is also possible to perform switching control of the current switching unit 50 and the switch unit 20 so that the output of the accident detection unit 40 is monitored for a predetermined waiting time, and branching to S180 or S130 (S132) is determined depending on whether an abnormal state is detected after the waiting time has elapsed. In this way, the switching device can perform a closing operation without determining that the starting current is abnormal.

[0055] The commutation switch 22 shown in FIG. 1 can be configured by a combination of a high melting point electrical contact and an arc chute, as shown in FIG. 5, in addition to the above-mentioned semiconductor switch.

[0056] 5, a commutation switch 22X according to the modified example includes a heat-resistant contact 114 and an arc chute 120 housed in a case 111. The heat-resistant contact 114 is made of a material having a higher melting point than silver and copper (e.g., tungsten or a nickel alloy, etc.). On the other hand, the electrical contact 21 can be made of silver or copper, which are typical materials having low electrical resistivity, or an alloy thereof.

[0057] The case 111 houses a movable electrode 112, a fixed electrode 113, and an electrode operation unit 118 for opening and closing a heat-resistant contact 114. Furthermore, terminals 115 to 117 that can be electrically contacted from the outside of the case 111 are arranged. The terminal 115 corresponds to the power supply side terminal of the commutation switch 22 in Fig. 1. The terminals 116 and 117 are load side terminals of the commutation switch 22 in Fig. 1, and the terminal 116 is connected to the accident detection unit 40 while the terminal 117 is connected to an electrical resistor 31.

[0058] The arc chute 120 has a pair of arc runners 121A, 121B and an arc-extinguishing unit 122 as a mechanical mechanism for extinguishing an arc that occurs when the heat-resistant contact 114 is turned on and off.

[0059] When a large current is introduced into the commutation switch 22 from the terminal 115, the electromagnetic force generated by the current automatically separates the movable electrode 112 from the fixed electrode 113. An arc generated between the electrodes in response to the separation of the movable electrode 112 is driven toward the arc chute 120 by the action of the magnetic field from the electrode.

[0060] After driving the arc in this manner, the arc is commutated to arc runner 121B, causing a current to flow to the load circuit side via arc runner 121B, electrode operation unit 118, and terminal 116. At this time, electrode operation unit 118 operates to hold movable electrode 112 in an open state by means of electromagnetic force.

[0061] After the arc is driven between arc runners 121A and 121B in this manner, the current starts to move from terminal 116 (accident detection unit 40) to terminal 117 (electrical resistance 31) due to the effect of the discharge resistance of the arc, and as time passes, the current is completely commutated so that it flows through electrical resistance 31. At this time, the current that has passed through electrical resistance 31 flows to the load circuit side via terminal 117, electrode operation unit 118, and terminal 116. This makes it possible to open (turn off) the commutation switch 22 while suppressing the passage of a large current.

[0062] 5, due to the above-mentioned operating principle, the determination of an abnormality is made based on the magnitude of the current passing through the movable electrode 112 or the fixed electrode 113. That is, when a current of a predetermined magnitude or more flows, the commutation switch 22X determines that an abnormality has occurred and automatically performs an OFF operation.

[0063] Moreover, the commutation switching unit 22X can be manually turned on and off by connecting it to an external circuit (not shown). That is, by connecting the external circuit to the terminals 116 and 117 and passing electricity between them, it becomes possible to control the opening and closing of the movable electrode using the electrode operation unit 118. For example, in S130 in Fig. 3 and S172 in Fig. 4, a trigger for turning on the commutation switching unit 22X can be given by passing a current through the electrode operation unit 118 using such an external circuit.

[0064] In this way, the commutation switching unit 22X shown in Fig. 5 is provided with the arc chute 120 for increasing the resistance of the arc discharge, thereby making it possible to ensure the breaking capacity when an abnormal state is detected in the abnormality diagnosis B. This makes it possible to realize the OFF operation of the commutation switching unit 22 in S170 or S172 in the switching control shown in Figs.

[0065] 1, the accident detection unit 40 is disposed closer to the load (i.e., node N2) than the switch unit 20. This results in greater changes in electrical signals such as voltage, current, and electrical resistance in the accident detection unit 40 compared to a configuration in which the accident detection unit 40 is disposed closer to the power supply (i.e., node N1) than the switch unit 20. As a result, it becomes easier to detect an abnormal state during abnormality diagnosis.

[0066] Alternatively, as shown in FIG. 6, the location of the accident detection unit 40 can be modified from that shown in FIG.

[0067] Referring to FIG. 6, in a switching device 10b according to a modified example of embodiment 1, the accident detection unit 40 is connected to the electrical resistance 31 on the load circuit side (node ​​N2 side) of the electrical resistance 31, and is connected in parallel to the switch unit 20.

[0068] In the switching device 10b according to the modification, the accident detection unit 40 can detect an abnormal state based on the amount of temperature rise in the electrical resistance 31 or the amount of absorbed energy in the electrical resistance 31 indicated by the integrated value of the square of the passing current, in addition to the above-mentioned electrical signals such as voltage, current, and electrical resistance. As a result, it becomes possible to perform the switching control shown in Fig. 3 or Fig. 4 so as to prevent a failure due to melting or the like of the electrical resistance 31.

[0069] Embodiment 2 FIG. 7 is a conceptual circuit diagram illustrating a configuration example of a switching device 10c according to the second embodiment.

[0070] 7, the switching device 10c includes a switch unit 20, a switching command unit 25, an electrical resistor 31 serving as a current suppression element 30, and an accident detection unit 40. The switch unit 20 includes an electrical contact 21 and a commutation switching unit 22 similar to those in the first embodiment, which are connected in parallel. The electrical contact 21 and the commutation switching unit 22 are turned on or off by the switching command unit 25. In this way, it can be understood that the switching device 10a (FIG. 1) according to the first embodiment further includes a current switching unit 50 between the switch unit 20 and the node N2, as compared with the switching device 10c according to the second embodiment.

[0071] In the switching device 10c of embodiment 2, a current switching unit 50 is not provided, and therefore the switch section 20 is not composed of only one of the electrical contacts 21 and the commutation switching unit 22, but is composed of the electrical contacts 21 and the commutation switching unit 22 connected in parallel.

[0072] Fig. 8 is a flowchart for explaining a control process of a circuit closing operation by the switching device according to embodiment 2. The control process shown in Fig. 8 is executed by, for example, the switching command unit 25 when a circuit closing operation is commanded to the switching device 10c.

[0073] 8, in S210, the switching command unit 25 maintains the electrical contacts 21 in the OFF state while turning on the commutation switching unit 22. This creates a "first state" between the nodes N1 and N2. That is, in the control process of FIG. 8, the "first value" of the impedance between the nodes N1 and N2 corresponds to the ON resistance of the commutation switching unit 22.

[0074] In this state, the opening / closing command unit 25 executes an abnormality diagnosis in S220. That is, in S220, it is determined whether or not an abnormal state is detected based on the output of the accident detection unit 40. Note that, in S220, similarly to S120 (FIGS. 3 and 4) in the first embodiment, the determination of abnormality or normality may be branched depending on whether or not an abnormal state is detected after a predetermined waiting time has elapsed.

[0075] If an abnormal state is detected, the process proceeds to S250, and the commutation switch 22 that was turned on in S210 is turned off. As described above, the commutation switch 22 is configured to have a certain degree of breaking capacity, unlike the electrical contacts 21. This makes it possible to interrupt the fault current in response to detection of an abnormal state, before the current has risen completely immediately after the commutation switch 22 is turned on. Then, because an abnormal state has occurred, the closing operation is terminated with both the electrical contacts 21 and the commutation switch 22 turned off.

[0076] On the other hand, if no abnormal state is detected in the determination (abnormality diagnosis) in S220, the switching command unit 25 further turns on the electrical contacts 21 in S230. Furthermore, the switching command unit 25 turns off the commutation switching unit 22 in S240. The process of S240 may be omitted, similar to S160 (FIG. 3).

[0077] In this way, in the switching device 10c, in a steady closed state after the closing operation, a current path with low impedance and large current carrying capacity can be formed between the nodes N1 and N2 by the electrical contact 21. As a result, a "second state" is formed between the nodes N1 and N2. That is, in the control process of Fig. 8, the "second value" of the impedance between the nodes N1 and N2 corresponds to the on-resistance value of the electrical contact 21 or the resistance value of the parallel connection of the on-resistance of the electrical contact 21 and the commutation switching unit 22.

[0078] In this way, the switching device 10c according to the second embodiment has a minimum configuration in which the current switching section 50 is omitted from the switching device 10a according to the first embodiment. In the switching device 10c, when the switch section 20 is open, a current path is formed by the electrical resistance 31. Therefore, although the switching device 10c does not have an interruption function by itself, even if an accident such as a short circuit occurs in the load circuit connected to the node N2, the switching device 10c It is possible to suppress the current flowing through (electrical resistance 31), and it has a current limiting function.

[0079] Furthermore, during the closing operation of the switch unit 20, the switching device 10c executes an abnormality diagnosis with only the commutation switching unit 22 turned on, and if no abnormality is detected in the abnormality diagnosis, a steady closed state is formed with the electrical contacts 21 turned on. As a result, if an overcurrent occurs due to an accident in response to the closing of the switch unit 20, the accident current can be interrupted by turning off the commutation switching unit 22. After the interruption, the current flowing through the switching device 10c is suppressed by the current limiting effect of the electrical resistance 31.

[0080] In the second embodiment, the accident detection unit 40 can be configured to detect an abnormality when the passing current at the location where it is installed is outside a predetermined reference current range. In this case, the switching command unit 25 operates to open the switch unit 20, that is, to turn off both the electrical contact 21 and the commutation switching unit 22, when the current passing through the accident detection unit 40 is lower or higher than the above-mentioned reference current range.

[0081] In this case, when a power source is not connected to node N1 and the current of the accident detection unit 40 is zero and lower than the above-mentioned reference current range, a closing operation is not commanded and the processing from S210 onwards is not started. Then, when a power source and a load circuit (not shown) are connected to nodes N1 and N2, respectively, and a passing current within the reference current range passes through the accident detection unit 40, an opening operation is commanded and the processing from S210 onwards is started. Then, in the abnormality diagnosis at S220, when the passing current of the accident detection unit 40 becomes higher than the reference current range, an abnormal state is detected and the above-mentioned opening and closing control can be realized.

[0082] Embodiment 3 9A to 9C, a modified example of the opening / closing command unit 25 of the switch unit 20 in the first and second embodiments will be described. The opening / closing command unit 25X according to the third embodiment also has the function of the accident detection unit 40, and has a mechanism for automatically controlling the on / off of the electrical contacts 21 according to the passing current of the accident detection unit 40 in the first and second embodiments.

[0083] Specifically, the opening / closing command unit according to the third embodiment 25X When the current passing through the accident detection unit 40 is within a predetermined reference current range, the electrical contact 21 is turned on, and when the current passing through the accident detection unit 40 is lower than the reference current range (low current) or higher than the reference current range (overcurrent), the electrical contact 21 is turned off.

[0084] FIG. 9A shows the state of the switching command unit 25X when the current passing through the coil 204 is low, that is, lower than the reference current range.

[0085] 9A, an opening / closing command unit 25X according to the third embodiment has an electromagnet 26 formed of iron cores 201 to 203 and a current-carrying conductor (coil) 204, and a connecting rod 27. The iron cores 201 and 203 are 202 9A, iron cores 201 to 203 are arranged such that a gap is generated between iron cores 201 and 202, and between iron cores 202 and 203.

[0086] The iron cores 201 and 202 are electrically connected to first and second contacts (not shown) constituting the electrical contact 21. When the iron cores 201 and 202 are in contact with each other, the first and second contacts are also closed, whereas when a gap is generated between the iron cores 201 and 202, the first and second contacts are also opened. The coil 204 is arranged so that the same current as that of the accident detection unit 40 passes through it.

[0087] The connecting rod 27 passes through a hole (not shown) provided in the fixed core 202, and integrally connects the cores 201 and 203. That is, the cores 201 and 203 are configured to be integrally movable relative to the fixed core 202 in response to an electromagnetic force generated by a current passing through the coil 204.

[0088] When no current flows through the coil 204, a biasing force 210 from a spring or the like (not shown) acts on the connecting rod 27, generating gaps between the iron cores 201 and 202, and between the iron cores 202 and 203. When the current is low, a magnetic path is formed as shown by the dotted line in FIG. 9A, but the magnetic force of the magnetic path is small, so no magnetic force (attraction force) is generated to eliminate the gaps. As a result, the gap between the iron cores 201 and 202 is maintained, and the first and second contacts connected to the nodes N1 and N2, respectively, are also maintained in an open state. That is, the electrical contact 21 is turned off.

[0089] FIG. 9B shows that the current passing through the coil 204 is within the reference current range. When The state of the opening / closing command unit 25X is shown.

[0090] As shown in Fig. 9B, when the current passing through the coil 204 becomes larger than that in the state of Fig. 9A, a magnetic path 250A passing through the iron cores 201 and 202 is formed. An electromagnetic force generated by the magnetic path 250A generates an attractive force 221 of the movable iron core 201 against the fixed iron core 202. As a result, a driving force 211 in the right direction in the figure, which exceeds the biasing force 210 in Fig. 9A, acts on the connecting rod 27 connected to the iron cores 201 and 203. As a result, the gap between the iron cores 201 and 202 is eliminated, and the iron cores 201 and 202 come into contact with each other, thereby closing the circuit between the first contact and the second contact. That is, the electrical contact 21 is turned on.

[0091] FIG. 9C shows the state of the switching command unit 25X when an overcurrent occurs, that is, when the current passing through the coil 204 is higher than the reference current range.

[0092] As shown in FIG. 9C, iron core 202 has a thin portion 202# having a smaller cross-sectional area than the other portions. When the magnetic flux density of magnetic path 250A increases from the state shown in FIG. 9B in response to an increase in current in coil 204, magnetic saturation occurs in thin portion 202#.

[0093] As shown in Fig. 9C, when such magnetic saturation occurs, a magnetic path 250B is formed penetrating the iron cores 201-203 so as to avoid the thin-walled portion 202# where the magnetic resistance has increased. The formation of the magnetic path 250B generates an attractive force 222 of the movable iron core 203 against the fixed iron core 202. As a result, a driving force 212 in the same direction as the biasing force 210 in Fig. 9A (leftward in the figure) acts on the connecting rod 27 connected to the iron cores 201 and 203. As a result, the gap between the iron cores 202 and 203 is eliminated, while a gap is generated between the iron cores 201 and 202, so that the first contact and the second contact are opened. That is, the electrical contact 21 is turned off.

[0094] 9A and 9B, core 201 corresponds to an embodiment of the "first core", core 202 corresponds to the "second core", and core 203 corresponds to an embodiment of the "third core". Driving force 211 and magnetic path 250A shown in Fig. 9B correspond to the "first driving force" and the "first magnetic path", respectively, and driving force 212 and magnetic path 250B shown in Fig. 9C correspond to the "second driving force" and the "second magnetic path", respectively.

[0095] The switching command unit according to the third embodiment controls the electrical contacts 21 from off to on when the passing current of the switching device rises from zero and falls within a predetermined reference current range, and can automatically turn off the electrical contacts 21 if an excessive current occurs due to an accident such as a short circuit in the load circuit while the electrical contacts are on. That is, the switching command unit according to the third embodiment can realize, by a hardware mechanism, the abnormality diagnosis during the closing operation of the switching device described in the first and second embodiments, by controlling the on / off of the electrical contacts 21 without transmitting and receiving a control signal.

[0096] The switching command unit 25X according to the third embodiment is applied to the on / off control of the electrical contact 21 which is connected in parallel with the commutation switching unit 22 to constitute the switch unit 20. That is, a switching command unit for controlling the on / off of the commutation switching unit 22 is provided for the commutation switching unit 22 as in the first and second embodiments, and the on / off of the electrical contact 21 can be automatically controlled by the operation of the switching command unit 25 when the commutation switching unit 22 is turned on.

[0097] In this manner, even in the configuration in which the on / off of the electrical contact 21 is automatically controlled by the opening / closing command unit 25X of embodiment 3, in the same manner as described in embodiments 1 and 2, in the switch unit 20 during closing operation, an abnormality diagnosis is performed with the commutation opening / closing unit 22 in the on state, and then the electrical contact 21 can be turned on in a steady closed circuit state.

[0098] Embodiment 4 FIG. 10 is a conceptual circuit diagram illustrating a configuration example of a switching device 10d according to the fourth embodiment.

[0099] 10, a switching device 10d includes a switch unit 20, a switching command unit 25, an energy absorption element 32 as a current suppression element 30, and an accident detection unit 40. The switch unit 20 includes an electrical contact 21 and a commutation switching unit 22 similar to those in the first embodiment, which are connected in parallel. The electrical contact 21 and the commutation switching unit 22 are turned on or off by the switching command unit 25.

[0100] The commutation switching unit 22 can be configured by a semiconductor switch or an electrical contact (for example, FIG. 5) as in the first and second embodiments. Of the functions of the switching command unit 25, the on / off function of the electrical contact 21 can also be applied to the switching command unit 25X according to the third embodiment (FIGS. 9A to 9C).

[0101] In this way, the switching device 10d according to the fourth embodiment differs from the switching device 10c according to the second embodiment (FIG. 7) in that the current suppression element 30 is constituted by an energy absorption element 32 instead of an electric resistor 31. The energy absorption element 32 is typically constituted by a varistor made of a material such as ZnO (zinc oxide). A varistor has non-ohmic properties and a voltage difference absorption capability (i.e., an interruption capability) like a diode, and has voltage-current characteristics that prevent a current from flowing even if a voltage difference equal to or less than the limit voltage, which is a specification value, is applied across both ends.

[0102] Alternatively, the energy absorbing element 32 may be a thermistor element whose electrical resistance increases with an increase in temperature. The thermistor element has an equivalent current interruption capability as its electrical resistance increases with the amount of heat generated by the energy of the overcurrent.

[0103] The opening and closing control of the switch section 20 during the closing operation of the switching device 10d is the same as in the second embodiment. That is, the on and off of the electrical contacts 21 and the commutation switching section 22 constituting the switch section 20 can be controlled according to the flowchart of Fig. 8. Furthermore, as described in the second embodiment, the abnormality diagnosis can also be performed so as to determine whether or not the current of the accident detection section 40 is within the reference current range. In this case, among the functions of the switching command section 25, the on and off control function of the electrical contacts 21 can be performed by using the hardware of the switching command section 25X according to the third embodiment.

[0104] The switching device 10d according to the third embodiment has a configuration in which the nodes N1 and N2 are constantly connected via a varistor (energy absorbing element), and therefore, even when both the electrical contacts 21 and the commutation switching unit 22 constituting the switch section 20 are turned off, the current between the nodes N1 and N2 can be interrupted by the energy absorbing element 32. That is, unlike the switching device 10c, the switching device 10d has an interrupting function even when the switch section 20 is open, despite not having the current switching unit 50 of Fig. 1.

[0105] Furthermore, during the closing operation of the switch unit 20, the switching device 10d executes an abnormality diagnosis with only the commutation switching unit 22 turned on, and if no abnormality is detected in the abnormality diagnosis, a steady closed state is formed with the electrical contacts 21 turned on. As a result, if an overcurrent occurs due to an accident in response to the closing of the circuit by the switch unit 20, the accident current can be interrupted by turning off the commutation switching unit 22. After the interruption, the current flowing through the switching device 10d can be interrupted by the energy absorption element 32 (varistor).

[0106] Embodiment 5. FIG. 11 is a conceptual circuit diagram illustrating a configuration example of a switching device 10e according to the fifth embodiment.

[0107] 11, the switching device 10e differs from the switching device 10d (FIG. 10) according to the fourth embodiment in that the switch section 20 is composed only of a semiconductor switch 23. The semiconductor switch 23 is connected between nodes N1 and N2, and is on / off controlled in response to a control signal from a switching command section 25. In the switching device 10e, the semiconductor switch 23 is on / off controlled during circuit operation, making it possible to configure the switch section 20 only with the semiconductor switch 23.

[0108] Fig. 12 shows a flowchart for explaining an example of control processing during a circuit closing operation of the switching device according to embodiment 5. The control processing shown in Fig. 12 is executed, for example, by the switching command unit 25 when a circuit closing operation is commanded to the switching device 10e.

[0109] 12, when opening / closing command unit 25 turns on semiconductor switch 23 in S310, it executes abnormality diagnosis in S320. In S320, an ON period of semiconductor switch 23 is set to a predetermined time length, and during the ON period, a passing current Isw of semiconductor switch 23 detected by accident detection unit 40 is compared with a predetermined determination current It. In S320, if Isw≧It is detected during the ON period, an abnormal state is detected.

[0110] The switching command unit 25 branches the process in S320 at the end of the on-period described above. If an abnormal state is detected during the on-period of the semiconductor switch 23, the process proceeds to S330, where the semiconductor switch 23 is turned off to provide an off-period of the semiconductor switch 23. This temporarily blocks the passing current Isw. In this manner, in the fifth embodiment, the abnormality diagnosis is performed by repeatedly turning the semiconductor switch 23 on and off. That is, in the control process of FIG. 12, the switching command unit 25 generates a control signal for repeatedly turning the semiconductor switch 23 on and off, thereby forming a "first state" between the nodes N1 and N2.

[0111] When the semiconductor switch 23 is turned off in S330, the opening / closing command unit 25 counts the number of times the semiconductor switch 23 is repeatedly turned on and off for abnormality diagnosis, and in S340, it is determined whether the number of times is less than a predetermined number. The processes of S310 to S340 are repeatedly executed until the number of times reaches the predetermined number. Typically, the semiconductor switch 23 can be turned on and off repeatedly with a constant switching period and a constant on-period ratio (duty ratio) to the switching period. Alternatively, the switching period can be set to a minimum at start-up and gradually lengthened, taking into consideration that the current is large at start-up.

[0112] When the passing current Isw during the on-period of the semiconductor switch 23 does not rise above the determination current It before the number of repetitions reaches a specified number, that is, when an abnormal state is not detected by the abnormality diagnosis of S320, the switching command unit 25 skips the processes of S330 and S340 and ends the closing operation of the switching device 10e. As a result, the semiconductor switch 23 is maintained in the on state and the closing operation is ended, so that a steady closing state is formed by the switching device 10e. That is, in the control process of FIG. 12, the switching command unit 25 generates a control signal for maintaining the semiconductor switch 23 on, so that a "second state" in which the equivalent impedance is lower than the "first state" is formed between the nodes N1 and N2.

[0113] On the other hand, if the passing current Isw during the on-period of the semiconductor switch 23 is equal to or greater than the determination current It, that is, if the detection of the abnormal state continues even after the number of repetitions reaches the specified number, a YES determination is made in S340, the semiconductor switch 23 remains in the off state, and the closing operation of the switching device 10e is terminated. In other words, since an abnormal state has occurred, the closing operation is terminated with the semiconductor switch 23 in the off state.

[0114] FIG. 13 shows an example of an operational waveform diagram of the semiconductor switch in the switching device according to the fifth embodiment.

[0115] Referring to FIG. 13, by repeatedly turning the semiconductor switch 23 on and off to perform an abnormality diagnosis, even when an abnormality such as a short circuit occurs, the semiconductor switch 23 is turned off while the passing current Isw is increasing, thereby preventing a large current from passing during the closing operation.

[0116] Furthermore, in a load circuit such as a motor, the load impedance is low when the motor starts up at a low rotation speed, but as the rotation speed increases, the load impedance increases and the current passing through the switchgear also decreases. In this case, a large inrush current occurs even in a normal state where no abnormality such as a short circuit occurs. Under normal conditions, the overcurrent state caused by the inrush current disappears over time, but when an abnormality occurs, the overcurrent state continues.

[0117] 12 can be preset according to a standby time corresponding to the time length for which the inrush current is eliminated in a normal state, that is, according to the characteristics of a load circuit (not shown) connected to node N2. When the switching device 10d is arranged for a load circuit in which no inrush current occurs and the starting current is not so large, the above-mentioned specified number can be reduced to complete the closing operation earlier.

[0118] By setting the specified number of times in this manner, the switching device 10e can be brought into a steady closed state after the inrush current is eliminated in the case of an inrush current in a normal state. At this time, the magnitude of the inrush current can also be suppressed by turning the semiconductor switch 23 on and off. On the other hand, when an overcurrent occurs due to an abnormality such as a short circuit, an abnormality diagnosis is performed so that the switching device 10e is opened. The specified number of times can be obtained from the standby time according to the characteristics of the load circuit described above and the switching period of the semiconductor switch 23 during the abnormality diagnosis. Therefore, it is noted for confirmation that the comparison of the number of on / off repetitions in S340 with the specified number of times is equivalent to the comparison of the elapsed time from the start of the closing operation and the standby time.

[0119] As described above, the switching device 10e according to the fifth embodiment can perform a closing operation accompanied by an abnormality diagnosis that appropriately detects an abnormal state when a load circuit having a characteristic that generates a large starting current is connected to a power source. Furthermore, the current passing through the switching device 10e during the closing operation, including the starting current under normal conditions, can be suppressed, thereby enhancing the effect of protecting the equipment.

[0120] The abnormality diagnosis in which the semiconductor switch 23 is repeatedly turned on and off as described in the fifth embodiment (FIGS. 12 and 13) can also be applied to the abnormality diagnosis (corresponding to S210, S220 in FIG. 8) performed with the electrical contacts 21 turned off while the commutation switching unit 22 (semiconductor switch) is turned on when the commutation switching unit 22 is configured as a semiconductor switch in the switching device 10d (FIG. 10) of the fourth embodiment.

[0121] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0122] 10a to 10e switching device, 20 switch section, 21 electrical contact, 22, 22X commutation switching section, 23 semiconductor switch, 25, 25X switching command section, 30 current suppression element, 31 electrical resistance, 32 energy absorption element, 40 accident detection section, 50 current switching section, 111 case, 112 movable electrode, 113 fixed electrode, 114 heat-resistant contact, 115 to 117 terminal, 118 electrode operation section, 120 arc chute, 121A, 121B arc runner, 122 arc extinguishing section, 201 to 203 iron core, 202♯ thin-walled section, 204 coil, 205 connecting rod, 210 biasing force, 211, 212 driving force, 221, 222 attraction force, 250A, 250B magnetic path, Isw Passing current (semiconductor switch), It decision current, N1, N2 nodes.

Claims

1. An opening and closing device, a switch section connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source; a current suppressing element connected in parallel with the switch unit between the first node and the second node; an accident detection unit formed by electrically connecting the first node and the second node, the accident detection unit detecting an abnormality in a current carrying circuit including the power supply and the load circuit; An opening / closing command unit that controls opening / closing of the switch unit, the switching command unit controls the switch unit so that a first state in which the impedance between the first node and the second node has a first value is formed during a closing operation of the switching device, and executes an abnormality diagnosis based on an output of the accident detection unit, and when no abnormal state is detected by the accident detection unit in the abnormality diagnosis, controls the switch unit so that a second state in which the impedance has a second value that is equal to or less than the first value is formed; The current suppressing element is an electrical resistor for current limiting, The switching device further includes a current switching unit connected between the switch unit and the second node, and the switching operation of the current switching unit is controlled by the switching command unit. The switch unit is configured by an electrical contact or a commutation switch unit, The opening / closing command unit turns off the switch unit while turning on the current opening / closing unit to form the first state and executes a first abnormality diagnosis, and if the accident detection unit does not detect an abnormal state in the first abnormality diagnosis, turns on the switch unit again to execute a second abnormality diagnosis, and if the accident detection unit does not detect an abnormal state in the second abnormality diagnosis, continues to turn on the current opening / closing unit and the switch unit to form the second state.

2. 2. The switching device according to claim 1, wherein, when the abnormal state is detected by the accident detection unit in the first abnormality diagnosis, the switching command unit turns off the current switching unit and keeps the switch unit off to terminate the closing operation, and when the abnormal state is detected by the accident detection unit in the second abnormality diagnosis, the switching command unit turns off the current switching unit and the switch unit to terminate the closing operation.

3. An opening and closing device, a switch section connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source; a current suppressing element connected in parallel with the switch unit between the first node and the second node; an accident detection unit formed by electrically connecting the first node and the second node, the accident detection unit detecting an abnormality in a current carrying circuit including the power supply and the load circuit; An opening / closing command unit that controls opening / closing of the switch unit, the switching command unit controls the switch unit so that a first state in which the impedance between the first node and the second node has a first value is formed during a closing operation of the switching device, and executes an abnormality diagnosis based on an output of the accident detection unit, and when no abnormal state is detected by the accident detection unit in the abnormality diagnosis, controls the switch unit so that a second state in which the impedance has a second value that is equal to or less than the first value is formed; The current suppressing element is an electrical resistor for current limiting, The switching device further includes a current switching unit connected between the switch unit and the second node, and the switching operation of the current switching unit is controlled by the switching command unit. The switch unit has a commutation switch unit and an electrical contact connected in parallel, the commutation switch has a breaking capacity larger than that of the electrical contact, and an impedance of the electrical contact in an on state is equal to or smaller than an impedance of the commutation switch in an on state; a switching device in which, in the first state, the switching command unit turns on the current switching unit while turning off the commutation switching unit and the electrical contacts in the switch unit to execute a first abnormality diagnosis, and if the abnormal state is not detected by the accident detection unit in the first abnormality diagnosis, the switching command unit turns on the commutation switching unit in the switch unit while turning off the electrical contacts to execute a second abnormality diagnosis, and if the abnormal state is not detected by the accident detection unit in the second abnormality diagnosis, the switching command unit forms the second state by turning on the current switching unit and the electrical contacts.

4. 4. The switching device according to claim 3, wherein, when the abnormal state is detected by the accident detection unit in the first abnormality diagnosis, the switching command unit turns off the current switching unit and maintains the commutation switching unit and the electrical contacts off in the switch unit to terminate the closing operation, and when the abnormal state is detected by the accident detection unit in the second abnormality diagnosis, the switching command unit turns off the current switching unit and the commutation switching unit and maintains the electrical contacts off to terminate the closing operation.

5. An opening and closing device, a switch section connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source; a current suppressing element connected in parallel with the switch unit between the first node and the second node; an accident detection unit formed by electrically connecting the first node and the second node, the accident detection unit detecting an abnormality in a current carrying circuit including the power supply and the load circuit; An opening / closing command unit that controls opening / closing of the switch unit, the switching command unit controls the switch unit so that a first state in which the impedance between the first node and the second node has a first value is formed during a closing operation of the switching device, and executes an abnormality diagnosis based on an output of the accident detection unit, and when no abnormal state is detected by the accident detection unit in the abnormality diagnosis, controls the switch unit so that a second state in which the impedance has a second value that is equal to or less than the first value is formed; The current suppressing element is an electrical resistor for current limiting, The switch unit has a commutation switch unit and an electrical contact connected in parallel, the commutation switch has a breaking capacity larger than that of the electrical contact, and an impedance of the electrical contact in an on state is equal to or smaller than an impedance of the commutation switch in an on state; a switching device, in which, in the first state, the switching command unit turns on the commutation switching unit while turning off the electrical contacts to execute the abnormality diagnosis, and if the fault detection unit does not detect the abnormal state in the abnormality diagnosis, the switching command unit forms the second state by turning on the electrical contacts.

6. An opening and closing device, a switch section connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source; a current suppressing element connected in parallel with the switch unit between the first node and the second node; an accident detection unit formed by electrically connecting the first node and the second node, the accident detection unit detecting an abnormality in a current carrying circuit including the power supply and the load circuit; An opening / closing command unit that controls opening / closing of the switch unit, the switching command unit controls the switch unit so that a first state in which the impedance between the first node and the second node has a first value is formed during a closing operation of the switching device, and executes an abnormality diagnosis based on an output of the accident detection unit, and when no abnormal state is detected by the accident detection unit in the abnormality diagnosis, controls the switch unit so that a second state in which the impedance has a second value that is equal to or less than the first value is formed; The current suppressing element is an energy absorbing element having an interruption capability, The switch unit has a commutation switch unit and an electrical contact connected in parallel, the commutation switch has a breaking capacity larger than that of the electrical contact, and an impedance of the electrical contact in an on state is equal to or smaller than an impedance of the commutation switch in an on state; a switching device, in which, in the first state, the switching command unit turns on the commutation switching unit while turning off the electrical contacts to execute the abnormality diagnosis, and if the fault detection unit does not detect the abnormal state in the abnormality diagnosis, the switching command unit forms the second state by turning on the electrical contacts.

7. 7. The switching device according to claim 5, wherein when the abnormal state is detected by the accident detection unit in the abnormality diagnosis, the switching command unit turns off the commutation switching unit and maintains the electrical contacts off to terminate the closing operation.

8. the commutation switching unit is configured with a semiconductor switch that is on / off controlled by the switching command unit, 7. The opening and closing device according to claim 6, wherein, in the first state, the opening and closing command unit performs the abnormality diagnosis by turning off the electrical contact while repeatedly turning on and off the semiconductor switch, and when the abnormal state is no longer detected by the accident detection unit during an on-period of the semiconductor switch before the number of repeated on-off cycles reaches a predetermined specified number, the opening and closing command unit forms the second state by turning on the electrical contact while maintaining the semiconductor switch on.

9. An opening and closing device, a switch section connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source; a current suppressing element connected in parallel with the switch unit between the first node and the second node; an accident detection unit formed by electrically connecting the first node and the second node, the accident detection unit detecting an abnormality in a current carrying circuit including the power supply and the load circuit; An opening / closing command unit that controls opening / closing of the switch unit, the switching command unit controls the switch unit so that a first state in which the impedance between the first node and the second node has a first value is formed during a closing operation of the switching device, and executes an abnormality diagnosis based on an output of the accident detection unit, and when no abnormal state is detected by the accident detection unit in the abnormality diagnosis, controls the switch unit so that a second state in which the impedance has a second value that is equal to or less than the first value is formed; The current suppressing element is an energy absorbing element having an interruption capability, the switch unit is configured with a semiconductor switch that is on / off controlled by the opening / closing command unit, The opening / closing command unit, in the first state, repeatedly turns the semiconductor switch on and off to perform the abnormality diagnosis, and if the abnormal state is no longer detected by the accident detection unit during an on-period of the semiconductor switch before the number of repeated on-off cycles reaches a predetermined specified number, forms the second state by maintaining the semiconductor switch on.

10. The commutation switch unit includes: A heat-resistant contact; 3. The switchgear according to claim 1 or 2, further comprising an arc chute for extinguishing an arc generated at the heat-resistant contact.

11. The commutation switch unit includes: a heat-resistant contact formed of a material having a higher melting point than the electrical contact; The switchgear according to any one of claims 3 to 8, further comprising an arc chute for extinguishing an arc generated at the heat-resistant contact.

12. The switching device according to any one of claims 1 to 11, wherein the accident detection unit is disposed on the second node side with respect to the switch unit and the current suppression element.

13. The opening and closing device according to any one of claims 1 to 11, wherein the accident detection unit detects the abnormal state based on an electrical signal including information on at least one of a current, a voltage, an electrical resistance, and a temperature rise in the current-carrying circuit, and measurement information including at least one of a distribution of frequency components of the electrical signal and optical information.

14. The opening and closing device according to any one of claims 1 to 5, wherein the accident detection unit is connected to the electrical resistance and detects the abnormal state based on measurement information including at least one of an amount of absorbed energy and an amount of temperature rise in the electrical resistance when the energized circuit is formed.

15. The switching device according to claim 13 or 14, wherein the accident detection unit sets a reference range for the measurement information using the measurement information collected during normal operation of the energized circuit, and detects the abnormal state when the measurement information obtained during the abnormality diagnosis falls outside the reference range.

16. An opening and closing device, a switch section connected between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source; a current suppressing element connected in parallel with the switch unit between the first node and the second node; an accident detection unit formed by electrically connecting the first node and the second node, the accident detection unit detecting an abnormality in a current carrying circuit including the power supply and the load circuit; An opening / closing command unit that controls opening / closing of the switch unit, the switching command unit controls the switch unit so that a first state in which the impedance between the first node and the second node has a first value is formed during a closing operation of the switching device, and executes an abnormality diagnosis based on an output of the accident detection unit, and when no abnormal state is detected by the accident detection unit in the abnormality diagnosis, controls the switch unit so that a second state in which the impedance has a second value that is equal to or less than the first value is formed; the accident detection unit detects the abnormal state based on an electric signal including information on at least one of a current, a voltage, an electric resistance, and a temperature rise in the energized circuit, and measurement information including at least one of a distribution of frequency components of the electric signal and optical information; The accident detection unit sets a reference range for the measurement information using the measurement information collected during normal operation of the energized circuit, and detects the abnormal state when the measurement information obtained during the abnormality diagnosis falls outside the reference range.

17. The opening and closing device according to any one of claims 1 to 7, wherein when the abnormal condition is detected by the accident detection unit in the abnormality diagnosis, if the abnormal condition is not detected after a predetermined waiting time has elapsed, the opening and closing command unit controls the switch unit so that the second state is formed, while when the abnormal condition is detected even after the waiting time has elapsed, the opening and closing command unit opens the switch unit and terminates the closing operation.

18. the accident detection unit detects the abnormal state when a passing current of the accident detection unit is higher than a predetermined reference current range; The opening and closing command unit is configured to generate a first driving force in a direction to turn on the electrical contacts when the passing current is within the reference current range by electromagnetic force from an electromagnet including a coil into which the passing current is introduced, and to generate a second driving force in a direction to turn off the electrical contacts when the passing current is higher than the reference current range.

19. A biasing force for turning off the electrical contact is applied to the electrical contact, the first driving force acts in a direction opposite to the biasing force and is greater than the biasing force; The switching device according to claim 18 , wherein the switching command unit is configured not to generate the first driving force when the passing current is lower than the reference current range.

20. The electromagnet is first and second iron cores arranged with a first gap therebetween; a third core disposed in an opposite direction to the first core across a second gap from the second core, the first and third iron cores are connected by a connecting rod and are arranged to be movable integrally with the fixed second iron core by the first or second driving force, the electrical contact is configured to be turned on when the first and second iron cores are in contact with each other and turned off when the first and second iron cores are not in contact with each other; The switching device according to claim 18 or 19, wherein the electromagnet is configured to generate the first driving force by forming a first magnetic path that drives the first iron core in a direction in which the first air gap is reduced when the passing current is within the reference current range, and to generate the second driving force by forming a second magnetic path that drives the third iron core in a direction in which the second air gap is reduced in response to occurrence of magnetic saturation in the first magnetic path when the passing current is higher than the reference current range.

21. 1. A method for controlling a switchgear disposed between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source, comprising: controlling, during a closing operation of the switchgear, a switch unit connected in parallel with a current suppressing element between the first node and the second node, so as to form a first state in which an impedance between the first node and the second node has a first value; performing, in the first state, an abnormality diagnosis for detecting an abnormality in a current carrying circuit including the power supply and the load circuit, the current carrying circuit being formed by electrically connecting the first node and the second node; controlling the switch unit so as to create a second state in which the impedance has a second value that is equal to or less than the first value when the abnormality diagnosis does not detect the abnormality; and opening the switch unit when the abnormality diagnosis detects the abnormal state. The current suppressing element is an electrical resistor for current limiting, The switching device further includes a current switching unit connected between the switch unit and the second node, The switch unit is configured by an electrical contact or a commutation switch unit, the first state is formed by turning off the switch unit and turning on the current switching unit, The abnormality diagnosis includes: a first abnormality diagnosis that is executed under the first condition; and and a second abnormality diagnosis that is executed by further turning on the switch unit when the abnormal state is not detected in the first abnormality diagnosis, A method for controlling a switching device, wherein the second state is formed by continuing to turn on the current switching unit and the switch unit when the abnormal state is not detected in the second abnormality diagnosis.

22. when the abnormal state is detected in the first abnormality diagnosis, turning off the current switching unit and maintaining the switch unit in an off state to terminate the closing operation; The method for controlling a switching device according to claim 21 , further comprising the step of turning off the current switching unit and the switch unit to terminate the closing operation when the abnormal state is detected in the second abnormality diagnosis.

23. A method for controlling a switching device disposed between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source, comprising: controlling, during a closing operation of the switchgear, a switch unit connected in parallel with a current suppressing element between the first node and the second node, so as to form a first state in which an impedance between the first node and the second node has a first value; performing, in the first state, an abnormality diagnosis for detecting an abnormality in a current carrying circuit including the power supply and the load circuit, the current carrying circuit being formed by electrically connecting the first node and the second node; controlling the switch unit so as to create a second state in which the impedance has a second value that is equal to or less than the first value when the abnormality diagnosis does not detect the abnormality; and opening the switch unit when the abnormality diagnosis detects the abnormal state. The current suppressing element is an electrical resistor for current limiting, The switching device further includes a current switching unit connected between the switch unit and the second node, The switch unit has a commutation switch unit and an electrical contact connected in parallel, the commutation switch has a breaking capacity larger than that of the electrical contact, and an impedance of the electrical contact in an on state is equal to or smaller than an impedance of the commutation switch in an on state; the first state is formed by turning on the current switching unit while turning off the commutation switching unit and the electrical contacts in the switch unit; The abnormality diagnosis includes: a first abnormality diagnosis that is executed under the first condition; and a second abnormality diagnosis that is executed in a state in which the commutation switching unit is turned on while the electrical contact is turned off in the switch unit when the abnormal state is not detected in the first abnormality diagnosis, A method for controlling a switching device, wherein the second state is formed by turning on the current switching unit and the electrical contacts when the abnormal state is not detected in the second abnormality diagnosis.

24. when the abnormal state is detected in the first abnormality diagnosis, turning off the current switching unit and maintaining the commutation switching unit and the electrical contacts in the switch unit in an off state to terminate the closing operation; 24. The method for controlling a switching device according to claim 23, further comprising the step of: when the abnormal state is detected in the second abnormality diagnosis, turning off the current switching unit and the commutation switching unit and maintaining the electrical contacts off to terminate the closing operation.

25. A method for controlling a switching device disposed between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source, comprising: controlling, during a closing operation of the switchgear, a switch unit connected in parallel with a current suppressing element between the first node and the second node, so as to form a first state in which an impedance between the first node and the second node has a first value; performing, in the first state, an abnormality diagnosis for detecting an abnormality state in a current carrying circuit including the power supply and the load circuit, the current carrying circuit being formed by electrically connecting the first node and the second node; controlling the switch unit so as to create a second state in which the impedance has a second value that is equal to or less than the first value when the abnormality diagnosis does not detect the abnormality; and opening the switch unit when the abnormality diagnosis detects the abnormal state. The current suppressing element is an electrical resistor for current limiting, The switch unit has a commutation switch unit and an electrical contact connected in parallel, the commutation switch has a breaking capacity larger than that of the electrical contact, and an impedance of the electrical contact in an on state is equal to or smaller than an impedance of the commutation switch in an on state; the first state is formed by turning on the commutation switch while turning off the electrical contacts; The second state is established by turning on the electrical contacts when the abnormal state is not detected in the abnormality diagnosis.

26. A method for controlling a switching device disposed between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source, comprising: controlling, during a closing operation of the switchgear, a switch unit connected in parallel with a current suppressing element between the first node and the second node, so as to form a first state in which an impedance between the first node and the second node has a first value; performing, in the first state, an abnormality diagnosis for detecting an abnormality in a current carrying circuit including the power supply and the load circuit, the current carrying circuit being formed by electrically connecting the first node and the second node; controlling the switch unit so as to create a second state in which the impedance has a second value that is equal to or less than the first value when the abnormality diagnosis does not detect the abnormality; and opening the switch unit when the abnormality diagnosis detects the abnormal state. The current suppressing element is an energy absorbing element having an interruption capability, The switch unit has a commutation switch unit and an electrical contact connected in parallel, the commutation switch has a breaking capacity larger than that of the electrical contact, and an impedance of the electrical contact in an on state is equal to or smaller than an impedance of the commutation switch in an on state; the first state is formed by turning on the commutation switch while turning off the electrical contacts; The second state is established by turning on the electrical contacts when the abnormal state is not detected in the abnormality diagnosis.

27. 27. The method for controlling a switching device according to claim 25, further comprising the step of turning off the commutation switching unit and maintaining the electrical contacts in an off state to terminate the closing operation when the abnormal state is detected in the abnormality diagnosis.

28. The commutation switching unit is configured with a semiconductor switch that is on / off controlled by a control signal, the first state is formed by generating the control signal to repeatedly turn the semiconductor switch on and off while turning off the electrical contacts; 27. The method for controlling a switching device according to claim 26, wherein the second state is formed by generating the control signal so as to turn on the electrical contact while maintaining the semiconductor switch on when the abnormal state is no longer detected during an on-period of the semiconductor switch before a number of repeated on-off cycles of the semiconductor switch reaches a predetermined specified number.

29. A method for controlling a switching device disposed between a first node electrically connected to a power source and a second node electrically connected to a load circuit receiving power from the power source, comprising: controlling, during a closing operation of the switchgear, a switch unit connected in parallel with a current suppressing element between the first node and the second node, so as to form a first state in which an impedance between the first node and the second node has a first value; performing, in the first state, an abnormality diagnosis for detecting an abnormality in a current carrying circuit including the power supply and the load circuit, the current carrying circuit being formed by electrically connecting the first node and the second node; controlling the switch unit so as to create a second state in which the impedance has a second value that is equal to or less than the first value when the abnormality diagnosis does not detect the abnormality; and opening the switch unit when the abnormality diagnosis detects the abnormal state. The current suppressing element is an energy absorbing element having an interruption capability, The switch unit is configured with a semiconductor switch that is controlled to be on / off by a control signal, the first state is formed by generating the control signal to repeatedly turn the semiconductor switch on and off; the second state is formed by generating the control signal to maintain the semiconductor switch on when the abnormal state is no longer detected during an on-period of the semiconductor switch before the number of repeated on-off cycles of the semiconductor switch reaches a predetermined specified number.

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