JP7188854B2 - DC current interrupter - Google Patents

Description

An embodiment of the present invention relates to a direct current interrupting device.

2. Description of the Related Art In recent years, electric power is transmitted through a DC system configured by a plurality of DC transmission lines. When an accident occurs in a DC system, there are cases where only a specific transmission line is cut off and power transmission is continued through the remaining transmission lines. With respect to this, there is known a technique related to a DC current interrupting device that includes both a mechanical contact and a semiconductor circuit breaker and interrupts current flowing through a DC power transmission line.

By the way, a direct current interrupting device may include a commutation circuit in addition to a mechanical contact and a semiconductor circuit breaker. This direct current interrupting device commutates the current flowing through the mechanical contact to a semiconductor circuit breaker by operating a commutation circuit, and when the semiconductor circuit breaker turns off, it interrupts a specific power transmission line. When commutating the current flowing through the mechanical contacts to the semiconductor circuit breaker, the commutation circuit operates to cause the current to extinguish the arc between the electrodes of the mechanical contacts. As a result, the mechanical contact is electrically and mechanically controlled to be in an open state, and the current flowing through the mechanical contact can be commutated to the semiconductor circuit breaker. Therefore, in order for the direct-current interrupter to interrupt a specific transmission line, it is required that the capacitor provided in the commutation circuit is charged at least during the initial state of the interrupting operation.

However, since the DC current interrupter is installed in a DC system with a very high voltage, the external power supply for charging the capacitor requires an isolation transformer with a withstand voltage equivalent to the DC system voltage. If the withstand voltage is very high, the insulating transformer may also be large.

JP 2016-162713 A

A problem to be solved by the present invention is to provide a direct current interrupting device capable of easily charging a capacitor provided in a commutation circuit.

A DC current interrupting device of an embodiment has a main circuit, a commutation circuit, and a charging circuit. The main circuit electrically interrupts or conducts the DC power transmission line that constitutes the DC system. The commutation circuit has a capacitor. The charging circuit has a first power supply, a second power supply, a first switch, and a second switching means. A first power supply supplies power supplied by a power supply to the capacitor. A second power supply supplies power supplied by the power supply to the capacitor. A first switch switches a connection state between the first power supply unit and the commutation circuit. The second opening/closing means switches a connection state between the second power supply section and the commutation circuit. A charging circuit charges the capacitor. The first power supply unit outputs larger power than the second power supply unit.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of a structure of the direct current interruption|blocking apparatus 1 of 1st Embodiment. 4 is a diagram showing an example of an initial state of a charging circuit 80 according to the first embodiment; FIG. 4 is a diagram showing an example of a normal conducting state of the charging circuit 80 according to the first embodiment; FIG. 5 is a flowchart showing an example of processing of the DC current interrupting device 1 related to charging of the capacitor C; It is a figure which shows an example of a structure of the 2nd transformer 84 of a modification. FIG. 10 is a diagram showing an example of a configuration of a charging circuit 80-1 according to a second embodiment; FIG. FIG. 13 is a diagram showing an example of the configuration of a charging circuit 80-2 of the third embodiment; FIG.

A DC current interrupting device according to an embodiment will be described below with reference to the drawings.

(First embodiment)
[Constitution]
FIG. 1 is a diagram showing an example of the configuration of a direct current interrupting device 1 according to the first embodiment. The DC current interrupting device 1 is a device for electrically conducting (energizing) or interrupting the first DC power transmission line LN1 and the second DC power transmission line LN2 among the DC power transmission lines constituting the DC system. In the following description, the DC voltage on the first DC power transmission line LN1 will be referred to as a first voltage VDC1, and the DC voltage on the second DC power transmission line LN2 will be referred to as a second voltage VDC2. The first voltage VDC1 and the second voltage VDC2 are, for example, voltages of several tens to several hundred [kV]. For example, power transmission facilities exist on the first DC power transmission line LN1 side, and consumers exist on the second DC power transmission line LN2 side. In this case, the first voltage VDC1 is normally higher than the second voltage VDC2. Therefore, normally, the DC system current flows in the direction from the first DC power transmission line LN1 to the second DC power transmission line LN2.

As shown in FIG. 1, the DC current interrupting device 1 includes, for example, a disconnector 10, a mechanical circuit breaker 20, a commutation circuit 30, a semiconductor circuit breaker 40, an arrester 50, a diode 60, and a reactor 70. , a charging circuit 80 , and a control unit 100 . The disconnector 10 includes a first terminal 10a and a second terminal 10b. The mechanical circuit breaker 20 has a first terminal 20a and a second terminal 20b. The commutation circuit 30 includes a first terminal 30a and a second terminal 30b. A circuit constituted by the mechanical circuit breaker 20, the commutation circuit 30, the semiconductor circuit breaker 40, the arrester 50, and the diode 60 in the direct current interrupting device 1 is an example of the "main circuit".

A first terminal 10a of the disconnecting switch 10 is connected to the first DC transmission line LN1. The illustrated reactor L1 virtually indicates an inductance component of the first DC power transmission line LN1. The second terminal 10b of the disconnecting switch 10, the first terminal 20a of the mechanical circuit breaker 20, and the first terminal 30a of the commutation circuit 30 are connected to each other.

Note that the DC current interrupting device 1 (disconnecting switch 10) may be connected to the first DC transmission line LN1 via an auxiliary disconnecting switch MS. A case where the disconnecting switch 10 is connected to the first DC transmission line LN1 via the auxiliary disconnecting switch MS will be described below. The auxiliary disconnector MS has a first terminal MSa and a second terminal MSb. The first terminal MSa is connected to the first DC transmission line LN1, and the second terminal MSb and the first terminal 10a are connected to each other.

A second terminal 20b of the mechanical circuit breaker 20 is connected to the second DC transmission line LN2. A reactor 70 is connected between the second terminal 20b and the second terminal 30b.

The semiconductor circuit breaker 40 includes, for example, a plurality of (four in the figure) switching units connected in series with each other. Each switching unit includes a switching element and a diode connected in parallel. Specifically, the cathode of the diode and the collector of the switching element are connected to each other, and the anode of the diode and the emitter of the switching element are connected. The switching element is, for example, a semiconductor switching element such as an insulated gate bipolar transistor (hereinafter, IGBT: Insulated Gate Bipolar Transistor). However, the switching elements are not limited to IGBTs. The switching element may be any element as long as it can realize self-extinguishing. In the following description, a case where the switching elements are IGBTs will be described. Further, in the following description, the emitter of the switching element of the switching section is also referred to as the "emitter of the switching section", and the collector of the switching element of the switching section is also referred to as the "collector of the switching section".

In the semiconductor circuit breaker 40, the emitter of the switching section and the collector of the switching section adjacent to the switching section are connected. The semiconductor circuit breaker 40 includes a first terminal 40a and a second terminal 40b. The first terminal 40a is connected to the collector of the terminal switching section among the plurality of switching sections of the semiconductor circuit breaker 40 and the cathode of the diode connected in parallel to the collector. The second terminal 40b is connected to the emitter of the switching section at the other end of the plurality of switching sections provided in the semiconductor circuit breaker 40 and the anode of the diode connected in parallel to the emitter.

The first terminal 40a, the second terminal MSb, and the first terminal 10a of the semiconductor circuit breaker 40 are connected to each other. Thereby, the semiconductor circuit breaker 40 is connected to the first DC transmission line LN1 via the auxiliary disconnector MS. A second terminal 40 b of the semiconductor circuit breaker 40 is connected to the anode of the diode 60 . The cathode of diode 60, second terminal 30b, and one end of reactor 70 are connected to each other. In the following description, the ON state of the switching element provided in the semiconductor circuit breaker 40 is also described as "the semiconductor circuit breaker 40 is in the closed state", and the switching element provided in the semiconductor circuit breaker 40 is in the OFF state. is also described as "the semiconductor circuit breaker 40 is in an open state".

The arrester 50 is connected in parallel with the semiconductor circuit breaker 40 between the first DC transmission line LN1 (in this example, the auxiliary disconnector MS) and the diode 60 . Arrestor 50 absorbs a surge voltage generated when semiconductor circuit breaker 40 is controlled to be open. The arrestor 50 is an example of a "lightning arrester".

Due to the connection relationship described above, the diode 60 allows the current to flow from the first DC power transmission line LN1 to the second DC power transmission line LN2, and allows the current to flow from the second DC power transmission line LN2 to the first DC power transmission line LN1. Block current flow.

The commutation circuit 30 includes, for example, a plurality of diodes (diodes 310a and 310b shown), a plurality of switching units (switching units 320a and 320b), a capacitor C, and a thyristor 35. Each of switching units 320a and 320b includes a switching element and a diode. The switching elements included in the switching units 320a and 320b and the diodes are connected in parallel with each other. Specifically, the cathode of the diode and the collector of the switching element are connected, and the anode of the diode and the emitter of the switching element are connected.

Capacitor C has a positive electrode and a negative electrode. Hereinafter, the voltage generated between the positive and negative electrodes of the capacitor C is also referred to as "capacitor voltage", and the circuit of the commutation circuit 30 that has the same potential as the positive electrode of the capacitor C is also referred to as the "positive electrode of the commutation circuit 30". , the circuit having the same potential as the negative terminal of the capacitor C in the commutation circuit 30 is also described as "the negative electrode of the commutation circuit 30". Diode 310a and switching section 320a are connected in series between the positive and negative poles of commutation circuit 30 in the order listed, and switching section 320b and diode 310b are connected in the order listed to the positive terminal of commutation circuit 30. and the negative electrode in series. The anode of diode 310a and the collector of switching section 320a are connected to each other. The emitter of switching section 320b and the cathode of diode 310a are connected to each other. The cathode of diode 310a, the collector of switching section 320b, and the positive electrode of capacitor C are connected to each other. The emitter of switching section 320a, the anode of diode 310b, and the negative electrode of capacitor C are connected to each other.

A first terminal 30a of the commutation circuit 30 is provided at a connection point between the anode of the diode 310a and the collector of the switching section 320a. A second terminal 30b of the commutation circuit 30 is provided at a connection point between the emitter of the switching section 320b and the cathode of the diode 310b. The anode of the thyristor 35 and the first terminal 30a of the commutation circuit 30 are connected to each other, and the cathode of the thyristor 35 and the second terminal 30b of the commutation circuit 30 are connected to each other.

Due to the connection relationship described above, the thyristor 35, in the OFF state, flows in the direction from the first DC power transmission line LN1 to the second DC power transmission line LN2, and flows in the direction from the second DC power transmission line LN2 to the first DC power transmission line LN1. Cut off both current flows. In the ON state, the thyristor 35 allows current to flow in the direction from the first DC power transmission line LN1 to the second DC power transmission line LN2 (that is, from the first DC power transmission line LN1 to the second DC power transmission line LN2). ) to block the current flowing in the direction from the second DC transmission line LN2 to the first DC transmission line LN1.

Note that the commutation circuit 30 may be a full bridge circuit including switching units 320c and 320d instead of the diodes 310a and 310b.

The charging circuit 80 includes a power supply device 81 , a first transformer 82 , a first switch 83 , a second transformer 84 , a second switch 85 and a rectifier 86 . The charging circuit 80 includes a first terminal 80a and a second terminal 80b. The first terminal 80 a is connected to the positive electrode of the capacitor C of the commutation circuit 30 . A second terminal 80 b is connected to the negative electrode of the capacitor C of the commutation circuit 30 . The first switch 83 has a first terminal 83a and a second terminal 83b. The second switch 85 has a first terminal 85a and a second terminal 85b. The second switch 85 is an example of "second opening/closing means".

The power supply device 81, the primary side of the first transformer 82, and the primary side of the second transformer 84 are connected to each other. The secondary side of the first transformer 82 and the first terminal 83a of the first switch 83 are connected to each other. The secondary side of the second transformer 84 and the first terminal 85a of the second switch 85 are connected to each other. The second terminal 83b and the rectifier 86 are connected. The second terminal 85b and the rectifier 86 are connected.

The power supply device 81 is supplied with commercial power, for example. The power supply device 81 supplies commercial power to the first transformer 82 and the first switch 83 . The power supplied to the power supply device 81 is not limited to commercial power, and may be transmitted power, distributed power, or stored power. Moreover, although the case where the charging circuit 80 is provided with the power supply device 81 was demonstrated, it is not restricted to this. The charging circuit 80 does not have to include the power supply device 81 as long as it can receive power from the power supply device 81 .

Each of the first transformer 82 and the second transformer 84 converts the voltage of the power supplied from the power supply device 81 into a voltage capable of charging the capacitor C. As shown in FIG. Here, the first transformer 82 is a converter having a lower withstand voltage than the second transformer 84 and a higher output power than the second transformer 84 . In other words, the second transformer 84 is a converter that has a higher withstand voltage than the first transformer 82 and a lower output power than the first transformer 82 . The voltage capable of charging the capacitor C is, for example, a voltage higher than the rated voltage of the capacitor C when rectified. In the first embodiment, the first transformer 82 is an example of a "first power supply", and the second transformer 84 is an example of a "second power supply". The first transformer 82 is implemented by, for example, an isolation transformer with low withstand voltage, and the second transformer 84 is implemented by, for example, an isolation transformer with high withstand voltage.

The first switch 83 has its opening/closing state controlled by the control unit 100, and connects the first transformer 82 and the capacitor C via the rectifier 86 in the closed state, and connects the first transformer 82 and the capacitor C in the open state. Cut off C. The second transformer 84 is controlled to open and close by the control unit 100. In the closed state, the second transformer 84 and the capacitor C are connected via the rectifier 86. In the open state, the second transformer 84 and the capacitor C are connected to each other. Cut off C. The first switch 83 and the second transformer 84 are implemented by mechanical contacts such as disconnectors and mechanical circuit breakers.

Rectifier 86 rectifies the power converted by first transformer 82 and the power converted by second transformer 84 . Note that the charging circuit 80 may not include the rectifier 86 when the power converted by the first transformer 82 and the second transformer 84 is direct current.

The control unit 100 controls the opening and closing of the auxiliary disconnecting switch MS, the disconnecting switch 10, the mechanical circuit breaker 20, the semiconductor circuit breaker 40, the first switch 83, and the second switch 85, and the ON/OFF switching control of the thyristor 35. , and control the operation of the commutation circuit 30 (that is, open/close control of the switching units 320a and 320b).

In a state in which the first DC power transmission line LN1 and the second DC power transmission line LN2 are electrically connected by the DC current interrupting device 1 (hereinafter referred to as normal conduction state), each part is in the following state. .
Auxiliary disconnector MS: closed state Disconnector 10: closed state Mechanical circuit breaker 20: closed state Semiconductor circuit breaker 40: open state Thyristor 35: OFF state Commutation circuit 30: OFF state Capacitor C included in flow circuit 30: charged state First switch 83: open state Second switch 85: closed state

As a result, in the normal conduction state, the DC system current flows from the first DC power transmission line LN1 to the second DC power transmission line LN2 via the path rt1 passing through the auxiliary disconnecting switch MS, the disconnecting switch 10, and the mechanical circuit breaker 20. flow.

When the DC current interrupter 1 electrically disconnects the first DC power transmission line LN1 and the second DC power transmission line LN2, the control unit 100 receives a disconnection instruction signal from a control system (not shown). The control system is, for example, a system that controls the supply (interchange) of electric power between power systems. to send. The disconnection instruction signal is, for example, a signal that instructs to electrically disconnect the first DC power transmission line LN1 and the second DC power transmission line LN2. Abnormalities in the DC system are, for example, abnormalities caused by accidents such as ground faults and short circuits that occur in DC transmission lines. When the control unit 100 receives a disconnection instruction signal from the control system, the control unit 100 controls the disconnecting switch 10 and the mechanical circuit breaker 20 to the open state, and the commutation circuit 30 (switching units 320a and 320b) to the ON state. Control.

Under the control of the control unit 100 described above, the disconnecting switch 10 of the direct current interrupting device 1 and the mechanical circuit breaker 20 are mechanically controlled to be in an open state. cannot be electrically cut off. In this state, the control unit 100 operates the commutation circuit 30, so that the switching units 320a and 320b included in the commutation circuit 30 are controlled to be on. Then, the commutation circuit 30 discharges the electric charge stored in the capacitor C, and from the positive electrode of the capacitor C to the negative electrode of the capacitor C via the switching unit 320b, the reactor 70, the mechanical circuit breaker 20, and the switching unit 320a. A circuit is formed in which the current circulates through the path rt2. This circuit is formed because the diode 60 is connected to the reactor 70 in the direction described above, so that the current flowing from the direction of the second DC power transmission line LN2 to the direction of the first DC power transmission line LN1 is blocked. This is because The current that circulates in this circuit is the current that flows in the direction opposite to the current that flows from the first DC power transmission line LN1 to the second DC power transmission line LN2 in the mechanical circuit breaker 20. Therefore, the arc generated in the mechanical circuit breaker 20 acts to cancel out As a result, the current flowing through the mechanical circuit breaker 20 becomes zero, and the mechanical circuit breaker 20 enters an electrical interruption state.

After that, the control unit 100 controls the semiconductor circuit breaker 40 to be closed. As a result, the DC system current flows from the first DC power transmission line LN1 to the second DC power transmission line LN2 via the auxiliary disconnecting switch MS, the disconnecting switch 10, the commutation circuit 30, and the reactor 70. The current is commutated to a path rt3 flowing from the line LN1 through the semiconductor circuit breaker 40, the diode 60, and the reactor 70 to the second DC transmission line LN2. Then, the control unit 100 controls the semiconductor circuit breaker 40 to open. A surge voltage generated when the semiconductor circuit breaker 40 is controlled to be open is absorbed by the arrester 50 . Thereby, the DC current interrupting device 1 can electrically interrupt the first DC power transmission line LN1 and the second DC power transmission line LN2.

Thus, in order for the DC current interrupting device 1 to electrically disconnect the first DC power transmission line LN1 and the second DC power transmission line LN2, the commutation circuit 30 operates to return the current to the path rt2. Desired.

In order for the commutation circuit 30 to circulate the current, the charging circuit 80 is required to charge the capacitor C to a predetermined charging capacity in the initial state. The predetermined charging capacity is, for example, the amount of electric power required for the capacitor voltage to reach a predetermined voltage, and the mechanical circuit breaker 20 can be electrically controlled to the open state when the commutation circuit 30 operates. is the amount of power required to circulate the current through path rt2. The predetermined voltage is, for example, the voltage of the capacitor C that can electrically control the mechanical circuit breaker 20 to the open state within a certain period of time. The initial state includes, for example, when the DC current interrupting device 1 is installed, when the DC current interrupting device 1 starts operating, when the DC current interrupting device 1 has not performed an interrupting operation so far, The DC current interrupting device 1 electrically disconnects the first DC transmission line LN1 and the second DC transmission line LN2 in a state where the capacitor C is not charged after the DC current interruption device 1 has performed the interruption operation. is blocked to

In addition, in order for the commutation circuit 30 to circulate the current, the charging circuit 80 is required to sequentially charge the amount of the natural discharge of the capacitor C after the initial state in the normal conduction state, and to maintain a predetermined charging capacity. . The normal conduction state is, for example, a state in which the first DC power transmission line LN1 and the second DC power transmission line LN2 are electrically connected by the DC current interrupting device 1 .

The state of the DC current interrupting device 1 when the capacitor C in the initial state is charged will be described below, and then the state of the DC current interrupting device 1 when the capacitor C in the normal conducting state is charged will be described.

[Charging of capacitor C in initial state]
In the initial state, the control unit 100 controls each part of the DC current interrupting device 1 as follows so that the DC current interrupting device 1 electrically disconnects the first DC power transmission line LN1 and the second DC power transmission line LN2. control to such a state.
Auxiliary disconnector MS: open state Disconnector 10: open state Mechanical breaker 20: open state Semiconductor breaker 40: open state Thyristor 35: off state Commutation circuit 30: off state Capacitor C included in flow circuit 30: not charged

When charging the capacitor C in the initial state, the control section 100 controls each section of the charging circuit 80 to the following states.
・First switch 83: closed state → open state ・Second switch 85: open state → closed state

FIG. 2 is a diagram showing an example of the initial state of the charging circuit 80 according to the first embodiment. In the state of FIG. 2, the first switch 83 is controlled to be closed and the second switch 85 is controlled to be open. The voltage converted by 1 transformer 82 is developed through rectifier 86 . Thereby, the capacitor C is charged with the power converted by the first transformer 82 .

In addition, in the initial state, if at least the first switch 83 is controlled to be closed, the second switch 85 may be controlled to be closed.

Next, when the capacitor C is charged to a predetermined charge capacity in the initial state, the control unit 100 controls the first switch 83 to open and the second switch 85 to close.

[Charging of Capacitor C in Normal Conduction State]
The control unit 100 controls each part of the DC current interrupting device 1 as follows so that the DC current interrupting device 1 electrically connects the first DC power transmission line LN1 and the second DC power transmission line LN2 in the normal conduction state. control to a good state.
Auxiliary disconnector MS: closed state Disconnector 10: closed state Mechanical circuit breaker 20: closed state Semiconductor circuit breaker 40: open state Thyristor 35: OFF state Commutation circuit 30: OFF state Capacitor C included in current circuit 30: Charged and naturally discharging state

Then, when charging the capacitor C which is in a normally conductive state, the control section 100 controls each section of the charging circuit 80 to the following states.
・First switch 83: open state ・Second switch 85: closed state

FIG. 3 is a diagram showing an example of the normal conduction state of the charging circuit 80 according to the first embodiment. In the state of FIG. 3, the first switch 83 is controlled to be open and the second switch 85 is controlled to be closed. The voltage converted by the 2-transformer 84 is developed through a rectifier 86 . Thereby, the capacitor C is charged with the power converted by the second transformer 84 .

[Operation flow]
FIG. 4 is a flow chart showing an example of processing of the DC current interruption device 1 for charging the capacitor C. As shown in FIG. First, the control unit 100 determines whether or not the state of the DC current interrupting device 1 is the initial state (step S100). When the control unit 100 determines that the state of the direct current interrupting device 1 is in the initial state, it controls the first switch 83 to close and the second switch 85 to open (step S102). Thereby, the capacitor C is charged with the power output by the first transformer 82 . When the control unit 100 determines that the state of the DC current interrupting device 1 is not the initial state, it assumes that the DC current interrupting device 1 is in the normal conduction state, controls the first switch 83 to open, and 2 switch 85 is controlled to be closed (step S104). Thereby, the capacitor C is charged with the power supplied by the second transformer 84 .

The control unit 100 determines whether or not the capacitor C in the initial state has been charged to a predetermined charging capacity by the power output from the first transformer 82 (step S106). The control unit 100 waits until the capacitor C in the initial state is charged up to a predetermined charging capacity. When the controller 100 determines that the capacitor C in the initial state has been charged to the predetermined charge capacity, it controls the first switch 83 to open and the second switch 85 to close (step S108). . As a result, the direct-current interrupting device 1 can switch its state to a normal conducting state while disconnecting the first transformer 82 having a low dielectric strength voltage in a state where the capacitor C is charged up to a predetermined charging capacity. .

[Summary of the first embodiment]
As described above, the direct current interrupting device 1 of this embodiment has mechanical contacts (in this example, the disconnecting switch 10 and the mechanical circuit breaker 20), the commutation circuit 30, and the charging circuit 80. The disconnecting switch 10 and the mechanical circuit breaker 20 are provided in a DC power transmission line (in this example, a connection point between the first DC power transmission line LN1 and the second DC power transmission line LN2) that constitutes the DC system. The commutation circuit 30 has a capacitor C. The charging circuit 80 includes a first power supply section (in this example, a first transformer 82), a second power supply section (in this example, a second transformer 84), a first switch 83, and a second It has a switch 85. The first transformer 82 supplies power supplied by the power supply device 81 to the capacitor C. As shown in FIG. The second transformer 84 supplies power supplied by the power supply device 81 to the capacitor C. As shown in FIG. The first switch 83 switches the connection state between the first transformer 82 and the commutation circuit 30 . The second switch 85 switches the connection state between the second transformer 84 and the commutation circuit 30 . A charging circuit charges the capacitor C. The first transformer 82 outputs larger power than the second transformer 84 .

Here, since the capacitor C is not charged in the initial state, the charging capacity required to charge the capacitor C is larger than that in the normal conduction state. As described above, first transformer 82 has a higher output power than second transformer 84 . In the initial state of the direct current interrupting device 1 of the present embodiment, between the first transformer 82 and the second transformer 84, by charging the capacitor C with the first transformer 82, the second transformer 84 Charging of the capacitor C can be completed in a short time as compared with charging the capacitor C.

Also, in the normal conduction state, the capacitor C is charged in the initial state and then naturally discharged, so the power capacity required to charge the capacitor C becomes smaller than in the initial state. In addition, since the DC system voltage is applied to the DC power transmission line LN in the normal conduction state, the internal circuit of the charging circuit 80 is required to have a high withstand voltage. In the normal conduction state, the DC current interrupting device 1 of the present embodiment charges the capacitor C with the second transformer 84, which has a high withstand voltage, out of the first transformer 82 and the second transformer 84, so that the charging circuit The naturally discharged charge capacity can be charged without dielectric breakdown of the capacitor 80 .

(Modification)
Modifications according to the first embodiment will be described below with reference to the drawings. 1st Embodiment demonstrated the case where the 2nd power supply part was implement|achieved by the one 2nd transformer 84. FIG. In a modified example, a case where the second power supply unit is implemented by a plurality of converters will be described. In addition, about the structure similar to embodiment mentioned above, the same code|symbol is attached|subjected and description is abbreviate|omitted.

FIG. 5 is a diagram showing an example of the configuration of the second transformer 84 of the modification. The second transformer 84 of the modified example is implemented by a plurality of isolation transformers TR connected in series between the power supply device 81 and the second switch 85 . In this example, the second transformer 84 is implemented by an isolation transformer TR-1, an isolation transformer TR-2, . . . , an isolation transformer TR-n (n is a natural number).

[Summary of modifications]
As described above, the second transformer 84 included in the DC current interrupting device 1 of the modification is implemented by a plurality of isolation transformers TR connected in series between the power supply device 81 and the second switch 85. . As a result, according to the DC current interrupting device 1 of the modification, the second transformer 84 with high withstand voltage can be realized by using a plurality of insulating transformers TR with low withstand voltage.

(Second embodiment)
A second embodiment will be described below with reference to the drawings. In the first embodiment, the case where the second power supply unit is implemented by the second transformer 84 has been described. In the second embodiment, a case where the second power supply unit is implemented by a configuration using an optical transmission line will be described. In addition, the same code|symbol is attached|subjected about the structure similar to embodiment and the modification which were mentioned above, and description is abbreviate|omitted.

FIG. 6 is a diagram showing an example of the configuration of the charging circuit 80-1 of the second embodiment. The charging circuit 80-1 of the second embodiment includes a power supply device 81, a first transformer 82, a first switch 83, a second switch 85, a rectifier 86, and a second power supply section 87. Prepare. The second power supply section 87 includes, for example, a laser driver LD, a light emitting element LE, an optical transmission line FB, a light receiving element RE, and a first conversion section CV1. The laser driver LD and power supply device 81 are connected to each other. The laser driver LD and the light emitting element LE are connected to each other. The light emitting element LE and the light receiving element RE are connected to each other by an optical transmission line FB. Specifically, the light emitting element LE is connected to the first end of the optical transmission line FB, and the light receiving element RE is connected to the second end of the optical transmission line FB. The light receiving element RE and the first converter CV1 are connected to each other. The first converter CV1 and the first terminal 85a are connected to each other. For example, commercial power is supplied to the power supply device 81 of the present embodiment, and the power supply device 81 converts the commercial power into power used by the laser driver LD.

The laser driver LD operates by power supplied from the power supply device 81, and controls the intensity of light emitted to the light emitting element LE and ON/OFF control. The light-emitting element LE emits light to the light-receiving element RE connected by the optical transmission line FB under the control of the laser driver LD. The laser driver LD and the light emitting element LE are examples of the "light emitting unit". Also, in the following description, the case where the intensity of the light emitted by the light emitting element LE is constant will be described.

The light receiving element RE receives light emitted by the light emitting element LE. The light receiving element RE outputs power according to the intensity of the received light. The light receiving element RE is realized by, for example, a photodiode. The power supplied by the photoreceptor RE varies, for example, in voltage and current depending on the light intensity and the output load. Here, the magnitude of the power supplied by the light receiving element RE is the power whose maximum value corresponds to the light emitted by the light emitting element LE and the conversion efficiency.

Note that the light receiving element RE may be configured to output electric power according to the wavelength of the received light. The light receiving element RE is an example of a "light receiving unit".

The first converter CV1 converts the voltage of the power output by the light receiving element RE into a predetermined voltage (for example, boosts or steps it down). As described above, the predetermined voltage is the charging voltage of the capacitor C, for example.

Note that the processing for controlling the state of the DC current interrupting device 1 depending on whether the control unit 100 is in the initial state or in the normal conduction state is the same as in the above-described embodiment, so description thereof will be omitted. omitted. Further, in the present embodiment, the DC current interrupting device 1 does not have to include the second switch 85 . In this case, the control unit 100 stops the operation of the laser driver LD in the initial state, and operates the laser driver LD in the normal conduction state. In addition, when the DC current interrupting device 1 does not include the second switch 85, the second power supply unit 87 functions as the "second switching means" as the operation or stop of the laser driver LD is switched. Also serves as

[Summary of the second embodiment]
As described above, the second power supply section 87 included in the DC current interrupting device 1 of the second embodiment has the laser driver LD, the light emitting element LE, the light receiving element RE, and the first conversion section CV1. . The laser driver LD uses power supplied by the power supply device 81 to cause the light emitting element LE to emit light. The optical transmission line FB has a first end connected to the light emitting element LE and a second end connected to the light receiving element RE. The light receiving element RE outputs electric power using light emitted by the light emitting element LE and transmitted by the optical transmission line FB. The first converter CV1 converts the power output from the light receiving element RE into power capable of charging the capacitor C. As shown in FIG. As a result, the DC current interrupting device 1 of the second embodiment can charge the capacitor C while ensuring sufficient dielectric strength in the normal conduction state.

(Third embodiment)
A third embodiment will be described below with reference to the drawings. In the first embodiment, the case where the second power supply unit is implemented by the second transformer 84 has been described. In the third embodiment, a case where the second power supply unit is realized by a configuration using a non-contact charging method will be described. In addition, the same code|symbol is attached|subjected about the structure similar to embodiment and the modification which were mentioned above, and description is abbreviate|omitted.

FIG. 7 is a diagram showing an example of the configuration of the charging circuit 80-2 of the third embodiment. The charging circuit 80-2 of the second embodiment includes a power supply device 81, a first transformer 82, a first switch 83, a second switch 85, a rectifier 86, and a second power supply section 88. Prepare. The second power supply unit 88 includes, for example, a power transmission circuit LC1, a power reception circuit LC2, and a second conversion unit CV2. Power supply device 81 and power transmission circuit LC1 are connected to each other. The power receiving circuit LC2 and the second conversion unit CV2 are connected to each other. The second converter CV2 and the first terminal 85a are connected to each other. For example, commercial power is supplied to the power supply device 81 of the present embodiment, and the power supply device 81 converts the commercial power into power used by the power transmission circuit LC1.

The power transmission circuit LC<b>1 is implemented by, for example, an excitation circuit in which a capacitor and a coil are connected in parallel, and the electric power supplied from the power supply device 81 causes the coil to generate a magnetic field. The power transmission circuit LC1 is an example of a "power transmission coil".

The power receiving circuit LC2 is implemented by, for example, an excitation circuit in which a capacitor and a coil are connected in parallel. In the power receiving circuit LC2, the magnetic field generated by the power transmitting circuit LC1 causes electromagnetic induction in the coil included in the power receiving circuit LC2, so that an induced electromotive force is generated by the electromagnetic induction. The power receiving circuit LC2 is an example of a "power receiving coil".

The second converter CV2 converts the voltage of the induced electromotive force output by the power receiving circuit LC2 into a predetermined voltage (for example, boosts or steps it down). As described above, the predetermined voltage is the charging voltage of the capacitor C, for example.

Note that the processing for controlling the state of the DC current interrupting device 1 depending on whether the control unit 100 is in the initial state or in the normal conduction state is the same as in the above-described embodiment, so description thereof will be omitted. omitted. Further, in the present embodiment, the DC current interrupting device 1 does not have to include the second switch 85 . In this case, the control unit 100 stops the operation of the power transmission circuit LC1 in the initial state, and operates the power transmission circuit LC1 in the normal conduction state. Further, when the direct current interrupting device 1 does not include the second switch 85, the second power supply unit 88 functions as a "second switching means" as the power transmission circuit LC1 is switched between operation and stop. Also serves as

[Summary of the third embodiment]
As described above, the second power supply unit 88 included in the direct current interrupting device 1 of the third embodiment includes the power transmission coil (the power transmission circuit LC1 in this example), the power reception coil (the power reception circuit LC2 in this example). ) and a second converter CV2. The power transmission circuit LC1 generates a magnetic field with power supplied by the power supply device 81 . The power receiving circuit LC2 generates power (induced electromotive force) by the magnetic field generated by the power transmitting circuit LC1. The second conversion unit CV2 converts the power output from the power receiving circuit LC2 into power capable of charging the capacitor C. FIG. As a result, the DC current interrupting device 1 of the third embodiment can charge the capacitor C while ensuring sufficient dielectric strength in the normal conduction state.

[Another example of the first switch 83 and the second switch 85]
In the above description, one first switch 83 is provided between the first power supply section and the rectifier 86, and one second switch 85 is provided between the second power supply section and the rectifier 86. Although the case where it is provided has been described, it is not limited to this. A plurality of switches may be provided in series between the first power supply section and the rectifier 86 and between the second power supply section and the rectifier 86 . As a result, the DC current interrupting device 1 can increase the withstand voltage of the first switch 83 and the second switch 85 .

[When a plurality of commutation circuits 30 are provided]
Moreover, although the case where the DC current interrupting device 1 includes one commutation circuit 30 has been described above, the present invention is not limited to this. The direct current interrupting device 1 may include a plurality of commutation circuits 30 . In this case, the direct current interrupting device 1 includes a commutation circuit 30-1, a commutation circuit 30-2, . The commutation circuits 30-2, . . . , 30-m are connected in series with each other. , commutation circuit 30-m are simply referred to as commutation circuit 30 when they are not distinguished from each other. Adjacent commutation circuits 30 have second terminals 30b and first terminals 30a connected to each other. Among the plurality of commutation circuits 30, the first terminal 30a, the second terminal 10b, and the first terminal 20a of the end commutation circuit 30 are connected to each other. Further, among the plurality of commutation circuits 30, the second terminal 30b of the commutation circuit 30 at the other end, the cathode of the diode 60, and one end of the reactor 70 are connected to each other. In this case, the first terminals 80a are connected to the positive terminals of the capacitors C of the commutation circuits 30, respectively, and the second terminals 80b are connected to the negative terminals of the capacitors C, respectively.

Here, in order for the commutation circuit 30 to operate when the mechanical circuit breaker 20 is electrically opened to return the current to the path rt2, a large number of capacitors C must be used to obtain a high capacitor voltage. may be required. According to the DC current interrupting device 1 having the plurality of commutation circuits 30, by connecting the capacitors C in series, the sum of the voltages of the plurality of capacitors C can realize a high capacitor voltage.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

REFERENCE SIGNS LIST 1 direct current interrupter, 10 disconnector, 20 mechanical circuit breaker, 30, 30-1, 30-2, 30-m commutation circuit, 35 thyristor, 40 semiconductor circuit breaker, 50 arrester , 60... diode, 70... reactor, 80, 80-1, 80-2... charging circuit, 81... power supply device, 82... first transformer, 83... first switch, 84... second transformer, 85... Second switch 310a, 310b Diode 320a, 320b, 320c, 320d Switching section C Capacitor CV1 First conversion section CV2 Second conversion section 86 Rectifier 87, 88 Second Power Supply Unit 100 Control Unit FB Optical Transmission Line L1 Reactor LC1 Power Transmission Circuit LC2 Power Reception Circuit LD Laser Driver LE Light Emitting Element LN1 First DC Transmission Line LN2 Second 2 DC transmission line, MS... Auxiliary disconnector, RE... Light receiving element, TR, TR-1, TR-2, TR-n... Insulation transformer

Claims (6)

A main circuit that electrically interrupts or conducts a DC power transmission line that constitutes a DC system;
a commutation circuit having a capacitor;
a first power supply unit that supplies power supplied by a power supply device to the capacitor; a second power supply unit that supplies power supplied by the power supply device to the capacitor; a first switch for switching a state of connection with a current circuit; and a second switching means for switching a state of connection between the second power supply unit and the commutation circuit, and a charging circuit for charging the capacitor. ,
The first power supply unit outputs larger power than the second power supply unit,
DC current interrupter. The first power supply unit has a lower dielectric strength voltage than the second power supply unit and outputs power larger than the second power supply unit;
The second power supply unit has a higher dielectric strength voltage than the first power supply unit and outputs power smaller than that of the first power supply unit.
The direct current interrupting device according to claim 1. Further comprising a control unit for controlling the opening/closing state of each of the first switch and the second opening/closing means,
The control unit
when the main circuit does not energize the DC power transmission line, at least the first switch is closed and the capacitor is charged with power output from the first power supply unit;
When the main circuit energizes the DC power transmission line, the first switch is opened and the second switching means is closed so that the power output from the second power supply unit causes the capacitor to to charge the
The direct current interrupting device according to claim 1 or 2. each of the first power supply and the second power supply comprises a transformer;
A first transformer included in the first power supply unit has a lower withstand voltage than a second transformer included in the second power supply unit, and outputs a larger amount of power than the second power supply unit.
The DC current interrupting device according to any one of claims 1 to 3. The second power supply unit includes: a light emitting unit that emits light using power supplied by the power supply device; an optical transmission line having a first end connected to the light emitting unit; a light-receiving unit connected to an end and outputting electric power using the light emitted by the light-emitting unit and transmitted by the optical transmission line; and converting the electric power output from the light-receiving unit into electric power capable of charging the capacitor. a conversion unit;
The DC current interrupting device according to any one of claims 1 to 4. The second power supply unit includes a power transmission coil that generates a magnetic field by power supplied by the power supply device, a power reception coil that generates power by the magnetic field generated by the power transmission coil, and power output from the power reception coil. a conversion unit that converts the capacitor into electric power that can be charged,
The DC current interrupting device according to any one of claims 1 to 5.

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