JP7212341B2 - Power switchgear, power transmission and distribution system, power generation system, load system, and control method for power switchgear - Google Patents

Description

The present invention relates to a power switchgear, a mechanical switch, a power transmission and distribution system, a power generation system, a load system, and a control method for a power switchgear.

In a power system, the generated power and the consumed power must be the same at the same time, and if the balance is lost, the frequency may fluctuate or the generator may step out. Therefore, when a system accident such as a short-circuit or ground fault or a short-circuit or ground fault due to equipment failure occurs, it is necessary to quickly isolate the accident location (accident point) from the system and minimize the accident area. For this reason, breakers such as vacuum circuit breakers and circuit breakers for breaking current paths when accidents such as ground faults and short circuits occur are installed in electric power systems and the like (see, for example, Patent Document 1). A mechanical circuit breaker such as that disclosed in Patent Document 1 interrupts current by separating electrodes.

JP-A-3-105818 JP 2017-130391 A

However, in the mechanical circuit breaker disclosed in Patent Document 1, if the current does not become zero, an arc occurs and continues, making it difficult to interrupt the current, and it is necessary to wait until the current becomes zero. In addition, it takes time to separate the electrodes to the required insulation distance, and it takes time to cut off. Furthermore, for example, circuit breakers used for extra high voltages (22 kV, 66 kV, 110 kV, etc.) or higher voltages require high voltage resistance, so the distance between the electrodes needs to be further increased. It takes time to cut off the current.

If a breaker such as the circuit breaking device described in Patent Document 2 is used, the current can be broken without waiting for the current to become zero, but the circuit configuration is complicated.

A power switchgear according to the present invention has at least the following configuration.
A power switching device having a parallel connection body of a mechanical switch and a semiconductor switch,
a control unit that controls the semiconductor switch to be in a connected state and then controls the mechanical switch to be in a connected state, thereby shifting the power switchgear from a non-conducting state to a conducting state;
The control unit maintains both the semiconductor switch and the mechanical switch in an ON state during the conduction state, and
When the power switchgear is to be shifted from the conducting state to the non-conducting state, the control unit performs control for confirming that the semiconductor switch is in the ON state, and then controls the mechanical switch to be in the non-connecting state. and then control to turn off the semiconductor switch,
The semiconductor switch is mounted on a metal body,
The heat capacity of the metal body on which the semiconductor switch is mounted is such that the amount of heat as the product of the heat capacity and the temperature change due to the temperature rise allowed for the semiconductor switch is larger than the amount of heat generated when the semiconductor switch is cut off. It is characterized in that it is set to a value of a sufficient heat capacity.

Further, the power switchgear of the present invention has a parallel connection body of a mechanical switch and a semiconductor switch,
The mechanical switch has a pair of electrodes, and the pair of electrodes are provided so as to be separated,
An on-voltage of the semiconductor switch is lower than an arc-generating voltage between the electrodes of the mechanical switch.

A power transmission and distribution system of the present invention has the power switchgear of the present invention.
A power generation system of the present invention is characterized in that a power generation device is connected to an electric power system via the power switchgear of the present invention.
Further, the load system of the present invention is characterized in that the load is connected to the power system via the power switchgear.

Further, a control method for a power switchgear according to the present invention includes at least the following configurations.
In a power switching device having a parallel-connected body of a mechanical switch and a semiconductor switch, the semiconductor switch is mounted on a metal body, and the heat capacity of the metal body on which the semiconductor switch is mounted is the same as the heat capacity and the semiconductor switch. A control method for a power switchgear, wherein a heat capacity value as a product of a temperature change due to an allowable temperature rise is set to a value greater than a heat quantity generated when the semiconductor switch is cut off,
The control unit controls the semiconductor switch to be in a connected state, and then controls the mechanical switch to be in a connected state, thereby shifting the power switchgear from the non-conducting state to the conducting state. Yes, and
The control unit maintains both the semiconductor switch and the mechanical switch in an ON state during the conduction state, and
After performing control to confirm that the semiconductor switch is on, the control unit performs control to disconnect the mechanical switch, and then performs control to turn off the semiconductor switch. As a result, the power switchgear is switched from the conducting state to the non-conducting state .

Advantageous Effects of Invention According to the present invention, it is possible to provide a power switchgear or a mechanical switch that quickly isolates an accident point. In addition, it is possible to provide electrical equipment such as a power conversion system using the power switchgear and mechanical switch, and contribute to improving the robustness of the power system (robustness against changes due to external factors).
Further, according to the control method of the power switchgear of the present invention, the fault point can be isolated quickly and easily.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the power distribution system which employ|adopted the switchgear for electric power which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the switchgear for electric power which concerns on embodiment of this invention. It is a figure which shows an example of the mechanical switch of the switchgear for electric power which concerns on embodiment of this invention. It is a figure which shows an example of the switchgear for electric power which employ|adopted IGBT and a diode (rectifier) as a semiconductor switch. 4 is a flow chart showing an example of an ON operation for controlling the power switchgear according to the embodiment of the present invention from a non-conducting state to a conducting state. 4 is a flowchart showing an example of a normal OFF operation for controlling the power switchgear according to the embodiment of the present invention from a conducting state to a non-conducting state. FIG. 5 is a flowchart showing an example of an abnormal turn-off operation when an abnormality is detected in the power switchgear according to the embodiment of the present invention; FIG. It is a figure which shows an example of the switchgear for electric power which has a several parallel connection body. It is a figure which shows an example of the switchgear for electric power with which the power supply for control is shared. It is a figure which shows an example of the switchgear for electric power which has multiple parallel connection bodies shown in FIG. It is a figure which shows an example of the switchgear for electric power with which the power supply for control is shared. 1 is a diagram showing an example of a power switchgear having a surge protection circuit; FIG.

A power switchgear according to an embodiment of the present invention has a parallel connection body of a mechanical switch and a semiconductor switch. The power switchgear also has a control unit that shifts the power switchgear from the non-conducting state to the conducting state by controlling the semiconductor switch to be in the ON state and the mechanical switch to be in the connected state.
In addition, the control unit turns the semiconductor switch on, disconnects the mechanical switch, and then turns off the semiconductor switch, thereby causing the power switchgear to shift from the conducting state to the non-conducting state. .

An embodiment of the present invention will be described below with reference to the drawings. Embodiments of the present invention include, but are not limited to, the illustrated content. In the following description of each figure, the same reference numerals are given to the parts that are common to the already described parts, and redundant description is partly omitted.

First, an example of a power system employing the power switchgear 100 (3, 4) according to the embodiment of the present invention shown in FIG. 1 will be described. An electric power system has a power source such as a generator (power generating device), power transmission and distribution facilities including distribution lines (transmission lines), and loads as power supply destinations. In addition, FIG. 1 extracts a power distribution system that occupies a part of the power system.

For example, an AC power supply as a power source 1 is connected to a plurality of distribution lines 6 of the AC power distribution system shown in FIG. there is A DC power source as a power source 2 is connected to the plurality of distribution lines 6 via a DC/AC converter (not shown), a transformer (not shown), a power switching device 4 (100), and the like. ing. A plurality of loads 5 as power supply destinations are connected to the plurality of distribution lines 6 .

For example, when an accident occurs in the distribution line 6 (transmission line), an accident occurs in the power source 1 or 2, an overcurrent or overvoltage occurs, or a large voltage fluctuation or current fluctuation occurs, other normal parts are protected. For this reason, the power switchgear 100 (3, 4) reliably cuts off power (current, etc.) in a short time, prevents it from spreading to other devices, suppresses frequency fluctuations in the power system, and To prevent the generators (generators) such as 1 and 2 from stepping out.
Alternatively, during maintenance, the power switchgear 100 (3, 4) similarly cuts off power (such as current) (disconnected state). In addition, when maintenance is completed or in normal operation, the power switchgear 100 (3, 4) is in a conductive state, and power is supplied from the power source 1 or the power source 2 to the load 5 to which power is supplied.
The power switchgear 100 (3, 4) according to one embodiment of the present invention can maintain, for example, simultaneous equality of an AC system or the like.
A power transmission and distribution system according to an embodiment of the present invention has a power switchgear provided between a power source and a distribution line or between a distribution line and a load.
Further, in the power generation system according to one embodiment of the present invention, a power source such as a power generation device (generator) is connected to the power system via the power switchgear.
A load system according to an embodiment of the present invention is one in which one or more loads are connected to a power system via a power switchgear.

As shown in FIG. 2, the power switchgear 100 according to the embodiment of the present invention includes a mechanical switch 10, a semiconductor switch 20 such as an FET (F1), a controller 71, and the like. Moreover, the power switchgear 100 shown in FIG.

The detection unit 72 is provided on the conductive line L1, for example, monitors the current, voltage, etc. of the conductive line L1, detects overcurrent, overvoltage, large voltage fluctuation, current fluctuation, etc., and outputs a signal indicating the detection result. Output to the control unit 71 .

The operation unit 73 is, for example, a touch panel type input display device, an operation button, an operation switch, an input device such as a keyboard (it may be provided with a display device), and for example, an ON command is issued in response to an operation by an operator. (Continuity instruction) or OFF instruction (Disconnection instruction) is output to the control unit 71 . Note that the operation unit 73 may be a control unit of a host system. Also, the control unit of the host system is not required to be directly operable by a human.

The control unit 71 integrally controls the mechanical switch 10, the semiconductor switch 20, and the like. The control unit 71 implements the functions according to the present invention by, for example, executing a control program stored in a storage unit within the control unit 71 .

For example, when the state between the terminal T1 and the terminal T2 is changed from the disconnected state to the conductive state, the control unit 71 controls the semiconductor switch 20 to be in the ON state and the mechanical switch 10 to be in the connected state.

Further, for example, when switching the connection between the terminals T1 and T2 from the conduction state to the non-conduction state, the control unit 71 turns the semiconductor switch 20 ON, disconnects the mechanical switch 10, and then turns the semiconductor switch 20 OFF. Control the state.

The first drive section 710 (mechanical switch drive section) and the second drive section 720 (semiconductor switch drive section) are connected to a common control power source 75 . In other words, power is supplied from the control power supply 75 to the first driving section 710 and the second driving section 720 .
For example, as a comparative example, compared with the case where the power supply for the first driving section 710 and the power supply for the second driving section 720 are provided, the first driving section 710 and the second driving section 720 are arranged as in the example shown in FIG. By using the common control power supply 75 in the , the number of drive unit power supplies can be reduced.
A driving power supply may be provided for each of the first driving section 710 and the second driving section 720 .

When the control unit 71 outputs a control signal for turning the semiconductor switch 20 on or off to the second driving unit 720 (semiconductor switch driving unit), the second driving unit 720 outputs , the semiconductor switch 20 is turned on or off.
Further, when the control unit 71 outputs a control signal for turning the mechanical switch 10 on or off to the first driving unit 710 (mechanical switch driving unit), the first driving unit 710 controls the According to the signal, the mechanical switch 10 is turned on (connected state) or off (disconnected state) by power from the control power supply 75 .

Further, in the power switchgear 100 shown in FIG. 2 , a semiconductor switch 20 is connected in parallel with the mechanical switch 10 . The parallel connection of the mechanical switch 10 and the semiconductor switch 20 is called a parallel connection body 30 . A terminal T1 is provided at one end of the conductive line L1 of the parallel connection body 30, and a terminal T2 is provided at the other end. A distribution line 6 (see FIG. 1) is connected to the terminals T1 and T2. The connection destination is not limited to the distribution line, and may be connected to a transmission line or the like.

Next, the mechanical switch 10 will be explained. Specifically, a pair of electrodes are provided in the mechanical switch 10 so as to be separated from each other. At the time of connection, both electrodes come into contact with each other and are in a connected state. In the mechanical switch of a conventional power switchgear, if the voltage applied between separated electrodes is high, arc discharge (arcing) is likely to occur. It was necessary to press the separable electrode into a highly insulating atmosphere such as a circuit breaker or gas circuit breaker.
For example, the control unit 71 outputs a control signal to the mechanical switch 10 through the control line L3 to set it to the disconnected state or the connected state.

An example of the mechanical switch 10 of the power switchgear according to the embodiment of the present invention will be described in detail with reference to FIG.
The mechanical switch 10 shown in FIG. 3 has a fixed side electrode 111 and a fixed side electrode rod 112 fixed to an insulating container 101, which is, for example, a high-vacuum vacuum container. A movable electrode 121 and a movable electrode rod 122 are movably provided in the insulating container 101 . A movable electrode rod 122 and a fixed electrode rod 112 are provided on the conductive wire L1. When the movable-side electrode 121 and the fixed-side electrode 111 are in contact with each other, the conductive line L1 is in a connected state, and when the movable-side electrode 121 and the fixed-side electrode 111 are separated from each other, the conductive line L1 is in a non-connected state.

In addition, when the ON voltage of the semiconductor switch 20 is high, or when it is difficult to mount the semiconductor switch 20 and the mechanical switch 10 close to each other, the mechanical switch 10 has a gap between the pair of electrodes 111 and 121 and the insulating container 101 . , having a shield 130 against arcing increases resistance to arcing.

The first drive unit 710 (mechanical switch drive unit) receives power from the control power source 75 and is controlled by the control unit 71 to control the movable electrode rod 122 protruding from the insulating container 101, for example. By moving the movable-side electrode rod 122 and the movable-side electrode 121 in the axial direction, the fixed-side electrode 111 and the movable-side electrode 121 are separated from each other or brought into contact with each other.

Note that the mechanical switch 10 is not limited to that shown in FIG. Examples of the mechanical switch 10 include a gas circuit breaker whose container is filled with inert gas, an oil circuit breaker whose container is filled with oil, a circuit breaker whose container is filled with air, a magnetic circuit breaker, and the like. can also be adopted. For example, if the ON voltage of the semiconductor switch 20 is low, the heat resistance of the semiconductor switch 20 is high, and the semiconductor switch 20 can be arranged close to the mechanical switch 10 (or one or more of them), the atmosphere in the container Arc generation can be suppressed even if management is not strict. The principle will be described later.

In addition, the power switchgear 100 shown in FIG. 2 employs a power semiconductor as the semiconductor switch 20. In FIG. 2, the power semiconductor is a bidirectional FET formed by laminating GaN on a Si chip. is shown as an example. For example, as the semiconductor switch 20, in addition to the FET (F1), a MOSFET, GaN, an insulated gate bipolar transistor, or the like can be employed. Note that the semiconductor switch 20 is not limited to this embodiment.
In the example shown in FIG. 2, the gate of the FET as the semiconductor switch 20 is connected to the control section 71 via the control line L2, and the source and drain are connected to the mechanical switch 10 connected to the conductive line L1. connected in parallel.

Further, if a bidirectional device such as a MOS-FET or FET is used, the semiconductor switch 20 described above can be composed of a single device. For example, the switch 20B can also have a configuration in which an IGBT and a diode are combined, as shown in FIG.

A power switchgear 100B shown in FIG. 4 has a semiconductor switch 20B (20) and a mechanical switch 10 connected in parallel 30B (30).
Parallel connection body 30B (30) has two insulated gate bipolar transistors (IGBT) BT1 and BT2 and two diodes D1 and D2 as semiconductor switches 20B (20).
In addition, the power switchgear 100B includes a first driving section 710 as a mechanical switch driving section, a second driving section 720 a as an IGBT (BT1) driving section, the second driving section 720 _a and the first driving section 720 _a . It has a control power source 75a that supplies power to the portion ₇₁₀ , _a second drive portion 720b as a drive portion for the IGBT (BT2), and _a control power source 75b that supplies power to the second drive portion _720a .

Specifically, the gate of one IGBT (BT1) is connected to the control unit 71 via the second driving unit 720 _a and the control line L2, the collector is connected to one end of the mechanical switch 10, and the emitter is It is connected to the anode of one diode D1, and the cathode of the diode D1 is connected to the other end of the mechanical switch 10.
The gate of the other IGBT (BT2) is connected to the control section 71 via the second driving section _720b and the control line L2, the collector is connected to the other end of the mechanical switch 10, and the emitter is connected to the other diode D2. , and the cathode of the diode D2 is connected to one end of the mechanical switch 10 .
That is, in the example shown in FIG. 4, an inexpensive semiconductor switch can be realized with a simple structure combining an IGBT and a diode. It should be _noted that _sharing the driving section as in the present embodiment makes it possible to reduce the size. It may be connected to a separate drive power supply.

Next, FIG. 5 and the like will be referred to as an example of the operation (hereinafter referred to as turn-on) of the power switchgear 100 shown in FIGS. Description will be made with reference to this. In the example shown in FIG. 5, the mechanical switch 10 includes a drive section for the mechanical switch, and the semiconductor switch 20 includes a drive section for the semiconductor switch.

When the voltage is blocked (disconnected state), both the semiconductor switch 20 and the mechanical switch 10 are off.

For example, when the operator operates the operation unit 73, a signal indicating an ON command is output from the operation unit 73 (ST1). When receiving the signal indicating the ON command from the operation unit 73, the control unit 71 outputs the signal indicating the ON command to the semiconductor switch 20, and performs processing for turning on the semiconductor switch 20 (ST2, ST3). Semiconductor switch 20 transitions to the ON state.

Next, after the semiconductor switch 20 has been turned on, or after the controller 71 has received an answerback signal indicating the on state from the semiconductor switch 20 and confirmed that the switch has been turned on (ST4, ST5), the machine is turned on. A control signal indicating an ON command is output to the formula switch 10 to turn on the mechanical switch 10 (ST6, ST7).

After the mechanical switch 10 is turned on, or after the control unit 71 receives an answerback signal indicating the on state from the mechanical switch 10 and confirms that the switch is turned on (ST8, ST9), the control unit 71 outputs a signal (on-confirmation signal) indicating that the semiconductor switch 20 and the mechanical switch 10 have been turned on, and performs processing for displaying this on the display device of the operation unit 73 (ST10). .

As described above, when the mechanical switch 10 is turned on, current flows through the mechanical switch 10 because the resistance of the mechanical switch 10 is lower than that of the semiconductor switch 20 . Specifically, if the semiconductor switch 20 is turned on first, the voltage applied to the mechanical switch 10 becomes the on voltage of the semiconductor switch 20 . If the ON voltage is lower than the voltage required to generate an arc (arc generation voltage), no arc is generated and the contact of the mechanical switch does not deteriorate.
An arc is generated by the electrons emitted from the electrodes colliding with the gas existing between the electrodes to ionize the gas, which is multiplied in an avalanche manner. Therefore, if the avalanche multiplication factor is less than one, no arc will occur. That is, it is preferable that the ON voltage of the semiconductor switch 20 is low. Specifically, it is preferable that the ON voltage of the semiconductor switch 20 is lower than the lowest voltage at which the electron multiplication of the electron avalanche between the electrodes becomes 1 when the pair of electrodes of the mechanical switch 10 are separated and not connected.
For example, wide-gap semiconductors such as SiC and GaN are known to have a lower on-voltage than Si-based semiconductors. If a semiconductor switch 20 with a sufficiently low on-voltage is used, it is not necessary to create a vacuum between the electrodes of the mechanical switch 10 or to enclose it under an insulating gas, thereby realizing simplification and cost reduction of the mechanical switch 10. can.

Next, an example of a normal OFF operation (hereinafter referred to as turn-off) in which the power switchgear 100 shifts from the conductive state to the voltage blocking state (disconnected state) will be described with reference to FIG. 6 and the like. In the conductive state, both the semiconductor switch 20 and the mechanical switch 10 are in the ON state (connected state).

For example, when a signal indicating an off command (disconnection command) is input from the operation unit 73 (ST11), the control unit 71 starts turn-off control.
Specifically, in the turn-off control, the control unit 71, for example, transmits a signal for checking the ON state of the semiconductor switch 20 (ST12), receives an answerback signal indicating the ON state from the semiconductor switch 20, and turns off the semiconductor switch. 20 is in the ON state (ST13, ST14), an OFF command is output to the mechanical switch 10 in order to shift the mechanical switch 10 to the OFF state (disconnected state). (ST15).

In step ST16, when the mechanical switch 10 receives a signal indicating an OFF command from the control section 71, the ON state is changed to the OFF state (turn OFF).

The control unit 71 receives the answerback signal indicating the off state from the mechanical switch 10, and confirms that the mechanical switch 10 is in the off state (ST17, ST18).

In step ST16 described above, if the mechanical switch 10 is turned off while the semiconductor switch 20 is in the ON state, ideally only the ON voltage of the semiconductor switch 20 is applied to the mechanical switch 10, so damage to the electrode due to arcing hard to receive Actually, since an inductance exists between the semiconductor switch 20 and the mechanical switch 10 , a voltage corresponding to the product of the current reduction rate of the mechanical switch 10 and the inductance is applied to the mechanical switch 10 . Therefore, it is important to mount the semiconductor switch 20 as close to the mechanical switch 10 as possible in order to suppress the voltage accompanying this current reduction. That is, when the semiconductor switch 20 is arranged close to the mechanical switch 10, the inductance between the semiconductor switch 20 and the mechanical switch 10 becomes small, and the voltage applied to the mechanical switch 10 accompanying the current decrease is reduced. can be reduced.

Also, the semiconductor switch 20 and the mechanical switch 10 may be connected via a wide conductor such as a busbar (metal conductor). As the bus bar, for example, a laminated bus bar formed by laminating (laminating) flat metal conductors via an insulator may be employed. Since the bus bars through which opposing currents flow can be arranged close to each other, the inductance can be reduced, and the voltage applied to the mechanical switch 10 can be reduced.
Letting L be the inductance between the semiconductor switch 20 and the mechanical switch 10, di/dt be the current reduction rate when the mechanical switch 10 is cut off, and _Va be the arcing voltage of the mechanical switch 10, the inductance L is , preferably satisfies equation (1).

Also, when the semiconductor switch 20 is mounted close to the mechanical switch 10, the semiconductor switch 20 is heated by a very slight arc. Therefore, it is more preferable that the semiconductor switch 20 is a semiconductor with high heat resistance, for example, a wide-gap semiconductor such as SiC or GaN.

Next, after the current has transferred to the semiconductor switch 20, or after the controller 71 confirms that the current has commutated to the semiconductor switch 20, the controller 71 turns off the semiconductor switch 20 (ST19, ST20). Specifically, control unit 71 outputs a control signal indicating an OFF command to semiconductor switch 20 in order to shift semiconductor switch 20 to the OFF state (ST19). In step ST20, when the semiconductor switch 20 receives a signal indicating an off command from the control unit 71, the semiconductor switch 20 transitions from the on state to the off state (turn off). At this time, a voltage corresponding to the product of the inductance of the distribution path in which the current changes and the rate of current decrease is applied to the semiconductor switch 20 . Therefore, semiconductor switch 20 preferably has an overvoltage suppression function. The overvoltage suppression function may be externally attached. Further, when the semiconductor switch 20 is cut off, the semiconductor switch 20 is subjected to a large thermal stress. Since this thermal stress is instantaneous, the semiconductor switch 20 is preferably mounted on a metal with a large heat capacity, such as a bulk metal. The product of the heat capacity of the metal body for mounting and the temperature change due to the allowable temperature rise must be greater than the amount of heat generated when the semiconductor switch 20 is turned off.
In addition, if the energy stored in the inductance is large immediately before the semiconductor switch 20 is cut off, a snubber circuit (for example, a resistor and a capacitor (capacitor) connected in series) to process the energy, or surge protection such as an arrester Devices are preferably connected in parallel with the semiconductor switch 20 .

After the semiconductor switch 20 has turned off, or after the control unit 71 receives an answerback signal indicating the off state from the semiconductor switch 20 and confirms that the semiconductor switch 20 has turned off (ST21, ST22), the control unit 71 outputs a signal (OFF confirmation signal) indicating that the semiconductor switch 20 and the mechanical switch 10 have been turned off to the operation unit 73, and performs processing to display that effect on the display device or the like of the operation unit 73. (ST23).

Next, an example of the turn-off operation when an abnormality such as an overcurrent is detected by the detection unit 72 will be described with reference to FIG. 7 and the like.
In the conductive state, both the semiconductor switch 20 and the mechanical switch 10 are in the ON state (connected state).

When an abnormality such as overcurrent is detected by the detection section 72, a signal (abnormality signal) indicating the detection of the abnormality is output from the detection section 72 to the control section 71 (ST31). Based on the signal, the control unit 71 determines whether or not to turn off the power switchgear (ST32), and if so, performs the processing of ST112 to ST123. Note that the processing of ST112 to ST122 shown in FIG. 7 is the same as the processing of ST12 to ST22 shown in FIG. 6, so description thereof will be omitted.
Then, in step ST122, after confirming that the semiconductor switch 20 and the mechanical switch 10 are turned off, the control unit 71, for example, outputs a signal (emergency OFF confirmation signal) is output to the operation unit 73, and processing is performed to display that fact on the display device or the like of the operation unit 73 (ST123).

Another embodiment of the present invention will be described below with reference to the drawings. In the following description of each figure, the same reference numerals are given to the parts that are common to the already described parts, and redundant description is partly omitted.

In the power switchgear 100C (100) according to _one embodiment of the present invention shown in _FIG . 8, FETs (F11, _F12 , , F1n) and _other semiconductor switches ₂₀ (201, 202, . . . , _20n ) are connected in parallel.
As shown in FIG. 8, the first drive units (710 ₁ , 710 ₂ , . . . , 710 _n ) and the second drive units ₍ 720 ₁ , 720 ₂ , . It is connected to control power sources (75 ₁ , 75 ₂ , . . . , 75 _n ). That is, from the power supply for control _{( 75 1} , _{75 2 , .} 720 ₂ , . . . , 720 _n ).
Also, in the power switchgear _100C (100), the parallel connection bodies 30 (30 ₁ , . A terminal T1 is provided at one end of the conductive line L1 of the structure 40, and a terminal T2 is provided at the other end. A distribution line 6 (see FIG. 1) is connected to the terminals T1 and T2.

Mechanical switches 10 ₁ to 10 _n are connected to conductive line L1 between terminals T1 and T2. Specifically, the mechanical switches 10 ₁ to 10 _n are provided with a pair of electrodes that can be separated from each other. The electrodes come into contact with each other and become connected. High-voltage mechanical switches, such as extra-high voltage switches, require a longer distance between electrodes to block voltage. Therefore, the distance between the electrodes becomes long when the current is cut off, and it takes time to cut off the current. Furthermore, if the voltage applied between the spaced apart electrodes is high, arc discharge (electrical arc) is likely to occur, and the arc extinguishment takes a long time. On the other hand, if the mechanical switches 10 ₁ to 10 _n are connected in series, the voltage assigned to each of the mechanical switches 10 ₁ to 10 _n will be low, so that the separation distance will be short, the time required for breaking will be short, and arcing will occur. In addition to reducing the possibility of arc extinguishing, it also has the advantage of shortening the time required to extinguish the arc.

Next, an example of the operation of the power switchgear 100C (100) shown in FIG. 8 will be described.
During voltage blocking, both the semiconductor switches 20 ₁ to 20 _n and the mechanical switches 10 ₁ to 10 _n are off. First, the operation at the time of transition from the voltage blocking state to the conducting state (referred to as turn-on) will be described.

The control unit 71 turns on the semiconductor switches 20 1 to 20 n , and after the semiconductor switches 20 ₁ to 20 _n have turned on or after the control unit 71 confirms that the semiconductor switches 20 ₁ to 20 _n have turned on, the control unit 71 turns on the mechanical switches 10 ₁ to 10 _n .

Since the mechanical switches 10 ₁ to 10 _n take time to open and close and have large individual differences, for example, the series-connected mechanical switches 10 ₁ to 10 _n are turned on without turning on the semiconductor switches 20 ₁ to 20 _n . Then, the full voltage is applied to the mechanical switch whose ON operation is delayed, and there is a risk of failure due to overvoltage.

_On the other hand, in the power _{switchgear 100C} ( ₁₀₀ ) according to the embodiment of the present invention shown in FIG. Even if the operation varies, only the ON voltage of the semiconductor switches 20 ₁ to 20 _n is applied to the mechanical switches 10 ₁ to 10 _n , so that they can be safely switched to the conductive state. In other words, one of the major features of the present invention is that it has a control section 71 that turns on the mechanical switches 10 ₁ to 10 _n after turning on the semiconductor switches 20 ₁ to 20 _n .

The operation when the power switchgear 100C (100) is turned off, as shown in FIG. 8, is the same as in the above-described embodiment (see FIGS. 6, 7, etc.), so the description is omitted.

As described above, each parallel-connected body of the power switchgear is connected in parallel with a control power supply (power supply circuit) that supplies the power necessary for the on/off operation of the mechanical switches and semiconductor switches. preferably. The control power supply (power supply circuit) extracts power from the applied voltage when the voltage is blocked, and uses it as operating power when turned on. On the other hand, when conducting, a minute current is shunted, and power is extracted from the shunted minute current and used as operating power at turn-off. The operating power at the time of turn-off may be extracted from the power supply circuit connected in series to each parallel connection.

For example, as in the power switchgear 100D ( ₁₀₀ ) shown in _FIG . , F22) may be adjacent to each other and connected to a power supply circuit as a common power supply/drive unit V, respectively. By doing so, it becomes possible to thin out the power supply circuits and drive units, and the number of power supply circuits and drive units in the entire power switchgear can be reduced. Specifically, in the example shown in FIG. 9, a common power supply/drive unit V is connected directly or via a resistor (not shown) to the drain of each FET (F21, F22). Note that FIG. 9 does not show an operation unit, a detection unit, and the like.

An example of the power/drive section V shown in FIG. 9 will be described.
The power/drive unit V has a plurality of switches SW1, SW2, SW3, SW4, capacitors C1, C2, resistors R1, R2, diodes D11, D12, and Zener diodes ZD1, ZD2, which are connected as shown in FIG. It is The switches SW1, SW2, SW3, and SW4 are controlled by the controller 71 to be in a connected state or a non-connected state. The switches SW1, SW2, SW3, and SW4 are semiconductor switches such as transistors and MOS-FETs, for example.

Specifically, in the example shown in FIG. 9, the drain of one FET (F21) and the drain of the other FET (F22) are connected via a node N1, and the node N1 is connected to the reference potential. . The source of one FET (F21) is connected to node N2, and one mechanical switch 10 ₁ (10) is connected between node N1 and node N2. The source of the other FET (F22) is connected to node N3, and the other mechanical switch 10 ₂ (10) is connected between node N1 and node N3.
A diode D11, a resistor R1, a capacitor C1 (capacitor), a capacitor C2, a resistor R2, and a diode D12 of the power/drive unit V are connected in series between the node N2 and the node N3. A connection node N4 between the capacitors C1 and C2 is connected to the drains of the FETs (F21 and F22) via the node N1.
Series-connected switches SW1 and SW2 and a Zener diode ZD1 are connected in parallel to both ends of one capacitor C1. The gate of one FET (F21) is connected between the switches SW1 and SW2 (connection node).
Series-connected switches SW3 and SW4 and a Zener diode ZD2 are connected in parallel across the other capacitor C2. The gate of the other FET (F22) is connected between the switches SW3 and SW4 (connection node).

Specifically, one of the diodes D11 mentioned above has an anode connected to the node N2 and a cathode connected to the resistor R1. The other diode D12 has an anode connected to the node N3 and a cathode connected to the resistor R2. When the potential of T2 is higher than T1, capacitor C2 is charged via diode D12 and resistor R2. On the other hand, when the potential of T1 is higher than T2, capacitor C2 is charged via diode D11 and resistor R1. C1 (capacitor) is charged. The voltages on capacitors C1 and C2 do not charge above the Zener voltages on ZD1 and ZD2, respectively.
The anode of one Zener diode ZD1 mentioned above is connected to switch SW2, and the cathode is connected to switch SW1. The other Zener diode ZD2 has an anode connected to the switch SW3 and a cathode connected to the switch SW4.
That is, as described above, the drains and gates of the series-connected MOS-FETs and FETs (F21, F22) of the adjacent semiconductor switches 20D ₁ and 20D ₂ (20) are connected to the common power supply/drive section V. It is possible to reduce the number of power supply circuits and drive units in the entire power switchgear. In this embodiment, especially, the conductor connecting the nodes N1 and N4 is common, and the common conductor can be reduced.

In addition, the power supply/drive unit V was the control power supply for the semiconductor switches _{20 (} 20D ₁ , 20D ₂ , . . . ) may also serve as a driving power supply for the driving unit. In other words, the semiconductor switch 20 and the mechanical switch 10 may be connected to a common power supply/drive section V. FIG.

A power switchgear 100E (100) according to an embodiment of the present invention shown in FIG. 10 includes a plurality of parallel-connected bodies 30B (30) shown in FIG. 4 connected in series.

A power switchgear 100E (100) shown in FIG. 10 is a parallel connection body of semiconductor switches 20 (20B ₁ , . . . , 20B _n ) and mechanical switches 10 (10 ₁ , . . . , 10 _n ). 30 (30B ₁ , . . . , 30B _n ). Each parallel connection body 30 (30B ₁ , . . . , 30B _n ) is connected in series to form a structure 40E (40).

. . , 30B _n (30), the parallel connection 30B ₁ (30) has _two insulated gate bipolar transistors IGBTs ( _BT11 , BT21), with two diodes D21 and D31.

In addition, the power switchgear 100E (100) includes first drive units (710 ₁₁ , . _{. . , 710 1n )} as drive units for the mechanical switches (10 ₁ , . _{BT11 , . _} Control power supplies (75 _a1 , . . . , 75 _an ) and _IGBTs ( _BT21 , . 2 drive units (720 _b1 , . . _{. , 720 bn )} and control power supplies (75 _{b1 , .} have

Specifically, the gate of one IGBT (BT11) is connected to the control unit 71 via the second driving unit 720 _a1 and the control line L2, and the collector is connected to one end of the mechanical switch 10 ₁ (10). , the emitter is connected to the anode of one diode D21, and the cathode of the diode D21 is connected to the other end of the mechanical switch 10 ₁ (10).
The gate of the other IGBT (B21) is connected to the control section 71 via the second driving section 720 _b1 and the control line L2, the collector is connected to the other end of the mechanical switch 10 ₁ (10), and the emitter is connected to the anode of the other diode D31 whose cathode is connected to the other end of the mechanical switch 10 ₁ (10).

Other components of the parallel connection are similarly configured. For example, the parallel connection 30B _n (30) includes two insulated gate bipolar transistors IGBTs (BT1n, BT2n) as semiconductor switches 20B _n (20). , has two diodes D2n, D3n. Specifically, the gate of one IGBT (BT1n) is connected to the control unit 71 via the second driving unit _720an and the control line L2, and the collector is connected to one end of the mechanical switch _10n (10). The emitter is connected to the anode of one diode D2n, the cathode of which diode D2n is connected to the other end of the mechanical switch 10 _n (10).
The gate of the other IGBT (B2n) is connected to the control section 71 via the control line L2 and the second driving section _720bn , the collector is connected to the other end of the mechanical switch _10n (10), and the emitter is It is connected to the anode of the other diode D3n, and the cathode of the diode D3n is connected to the other end of the mechanical switch 10 _n (10).

Further, as shown in FIG. 11, the power switchgear 100F (100) according to one embodiment of the present invention has a plurality of parallel-connected bodies 30 ( _30F1 , _30F2 , . . . ). Each semiconductor switch 20 (20F ₁ , 20F ₂ , . . . ) includes two insulated gate bipolar transistors IGBTs (BT41, BT51, BT42, BT52, . . . , D52, . . . ) and arranged as shown in FIG. It is possible to reduce the number of power supplies, drive units, and the like. Note that FIG. 11 does not show an operation unit, a detection unit, and the like.

Specifically, as shown in FIG. 11, for example, in one parallel connection body 30F ₁ (30), the collector of one IGBT (BT41) is connected to the cathode of one diode D41, and the anode of diode D41 is connected to the mechanical It is connected to one end (node N1) of the mechanical switch 10 ₁ (10), and the emitter of the IGBT (BT41) is connected to the other end of the mechanical switch 10 ₁ (10).
The gate of the other IGBT (BT51) is connected to the power supply/drive unit V, the collector is connected to the cathode of the diode D51, the anode of the diode 51 is connected to the other end of the mechanical switch 10 ₁ (10), The emitter of the IGBT (BT51) is connected to one end (node N1) of the mechanical switch 10 ₁ (10).

In the parallel connection body 30F ₂ (30), the gate of the IGBT (BT42) is connected to the power/drive unit V, the collector is connected to the cathode of one diode D42, and the anode of the diode D42 is connected to the mechanical switch 10 ₂ (10 ), and the emitter of the IGBT (BT42) is connected to the other end (the end connected to the node N1) of the mechanical switch 10 ₂ (10).
The collector of the other IGBT (BT52) is connected to the cathode of the other diode D52, and the anode of diode D52 is connected to the other end of mechanical switch 10 ₂ (10) (the end connected to node N1). and the emitter of the IGBT (BT52) is connected to one end of the mechanical switch 10 ₂ (10).

The power supply/drive section V shown in FIG. 11 has the same structure as the power supply/drive section V shown in FIG. 9, so the description thereof will be omitted. The other parallel connection body 30 and the power/drive section V have the same configuration.
Also, the gate of the IGBT (BT51) shown in FIG. 11 is connected between the switch SW1 and the switch SW2 of the power/drive unit V (connection node). A gate of the IGBT (BT42) is connected between the switch SW3 and the switch SW4 of the power/drive unit V (connection node). A connection node N4 between the switches SW2 and SW3 is connected to a connection node (node N1) between the semiconductor switches 20F ₁ and 20F ₂ .
In other words, the IGBT (BT51) of the adjacent semiconductor switch _20F1 and the IGBT (BT42) of the semiconductor switch _20F2 can share the power supply/drive section V. In other words, by sharing the power source/driving unit in the other adjacent parallel connection body 30F (30) of the power switchgear 100F (100), it is possible to thin out the power source/driving unit. It is possible to reduce the number of the power supply/driving unit, control power supply, and each driving unit of the entire device 100F (100).
Further, as described above, the power supply/drive unit V is a control power supply for each semiconductor switch, but it may also serve as a drive power supply for each mechanical switch drive unit. That is, the semiconductor switch and the mechanical switch may be connected to a common control power source or the like.
The IGBT (BT52) and the IGBT (not shown) above the parallel connection (not shown) next to the parallel connection 30F2 (30) (on the right side in FIG. 11) are driven by a common power source driving section. be.

As shown in FIG. 12, in the power switchgear 100G (100) according to one embodiment of the present invention, the semiconductor switch 20 and the mechanical switch 10 are provided with a capacitor and a resistor connected in series as measures against surge current. connected in parallel. A control power supply and each driving unit are not shown.
Specifically, mechanical switches 10 (10 ₁ , 10 ₂ , . . . , 10 _n ) and semiconductor switches 20 (20 ₁ , 20 ₂ , . . . , _{20 n )} connected in series with a capacitor C21 and a resistor R21, _a capacitor C22 and a resistor R22, . Each resistor R2n may be connected in parallel.
Also, as shown in FIG. 12, a series-connected capacitor C4 and a resistor R4 are connected in parallel at both ends of the series-connected structure 40 of each parallel-connected body 30 (30 ₁ , 30 ₂ , . . . , 30 _n ). may be connected. A surge protection device (arrestor) may be connected in parallel with the parallel body of the capacitor and resistor (not shown).
Also, as shown in FIG. 12, a surge protection device SP (arrester) such as an arrester (lightning arrester) is provided at both ends of the series connection structure 40 of each parallel connection 30 (30 ₁ , 30 ₂ , . . . , 30 _n ). ) may be connected in parallel. This arrester reduces the impedance only when a surge enters, passes overvoltage as a surge current, suppresses the surge voltage applied to the semiconductor switch 20 and the mechanical switch 10, and protects the semiconductor switch 20 and the mechanical switch 10. be able to.

As described above, the power switchgear 100 of the present invention includes the parallel connection body 30 of the mechanical switch 10 and the semiconductor switch 20, the controller 71, and the like. When connecting the terminals T1 and T2 of the parallel-connected body 30 from the disconnected state to the conductive state, the control unit 71 turns on the semiconductor switches 20 of the plurality of serially-connected structures 40 and turns the mechanical switches 10 on. to control.
In other words, it is possible to provide a power switchgear and a mechanical switch capable of quickly isolating the fault point.
In addition, it is possible to provide electrical equipment such as a power conversion system using the power switchgear and mechanical switch, and contribute to improving the robustness of the power system (robustness against changes due to external factors).

In addition, a power switchgear is provided that can reliably switch from a non-conducting state to a conducting state in a short period of time by using inexpensive mechanical switches and semiconductor switches with a low withstand voltage without using a circuit breaker with a high withstand voltage. can do. Specifically, for example, 500 kV or more, 275 kV, 220 kV, 187 kV using a plurality of mechanical switches 10, a plurality of semiconductor switches 20 for 400 V, 3.3 kV, 6.6 kV, or voltages therebetween. , 154 kV, 110 kV, 77 kV, 66 kV, 30 kV, 20 kV or voltages therebetween.

Further, as described above, the method for controlling the power switchgear includes a first step in which the semiconductor switch 20 is in the ON state and the mechanical switch 10 is in the non-connected state, and the control unit 71 controls the mechanical switch 10 a second step (ST2 to ST9 in FIG. 5) of shifting the power switchgear from the non-connected state to the conductive state by performing control from the non-connected state to the connected state. That is, it is possible to provide a control method for an electric power switchgear that can easily and quickly isolate a fault point through simple control.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and design changes and the like may be made without departing from the gist of the present invention. are included in the present invention.
Further, the embodiments shown in the respective drawings described above can be combined with each other as long as there is no particular contradiction or problem in the purpose, configuration, or the like.
In addition, the contents described in each drawing can be an independent embodiment, and the embodiment of the present invention is not limited to one embodiment in which each drawing is combined.

In the above-described embodiment, an AC power distribution system employing the power switchgear and the mechanical switch according to the present invention has been described, but the present invention is not limited to this embodiment. Devices and mechanical switches may be used for DC power distribution and used in DC power distribution systems.

1, 2... power source (generator)
3, 4, 100, 100B, 100C, 100D, 100E, 100F, 100G... Power switchgear 5... Load 6... Distribution line (transmission line)
DESCRIPTION OF SYMBOLS 10... Mechanical switch 20... Semiconductor switch 30... Parallel-connected body 40... Structure (plural series-connected structures)
71... Control part 72... Detection part 73... Operation part 75... Control power supply (power supply)
DESCRIPTION OF SYMBOLS 101... Insulating container 111... Fixed-side electrode 112... Fixed-side electrode bar 121... Movable-side electrode 122... Movable-side electrode bar 130... Shield 710... Drive unit for mechanical switch (first drive unit)
720... Drive unit for semiconductor switch (second drive unit)
C ... capacitor (capacitor)
D... Diode IGBT... Insulated gate bipolar transistor L1... Conductive line L2... Control line L3... Control line R... Resistor SP... Surge protective device (arrestor)
V: power supply and driving unit

Claims (15)

A power switching device having a parallel connection body of a mechanical switch and a semiconductor switch,
a control unit that controls the semiconductor switch to be in a connected state and then controls the mechanical switch to be in a connected state, thereby shifting the power switchgear from a non-conducting state to a conducting state;
The control unit maintains both the semiconductor switch and the mechanical switch in an ON state during the conduction state, and
When the power switchgear is to be shifted from the conducting state to the non-conducting state, the control unit performs control for confirming that the semiconductor switch is in the ON state, and then controls the mechanical switch to be in the non-connected state. and then control to turn off the semiconductor switch,
The semiconductor switch is mounted on a metal body,
The heat capacity of the metal body on which the semiconductor switch is mounted is such that the amount of heat as the product of the heat capacity and the temperature change due to the temperature rise allowed for the semiconductor switch is larger than the amount of heat generated when the semiconductor switch is cut off. A power switchgear, characterized in that it is set to a value of a heat capacity. 2. A power switchgear according to claim 1 , wherein a plurality of said parallel-connected bodies are connected in series. 3. The power switchgear according to claim 1, wherein the ON voltage of the semiconductor switch is lower than the arc generation voltage of the mechanical switch. 4. The power switchgear according to any one of claims 1 to 3 , wherein the semiconductor switch is arranged close to the mechanical switch. 5. The power switchgear according to claim 1 , wherein said semiconductor switch and said mechanical switch are connected via a bus bar. 6. The power switchgear according to claim 5 , wherein the busbar is a laminate busbar. Letting L be the inductance between the semiconductor switch and the mechanical switch, di/dt be the current reduction rate when the mechanical switch is interrupted, and _Va be the arcing voltage of the mechanical switch, then the inductance L is 7. The power switchgear according to any one of claims 1 to 6 , wherein the following equations (1) are satisfied.

The power switchgear according to any one of claims 1 to 7 , wherein the semiconductor switch is made of a heat-resistant wide-gap semiconductor. 9. The power switchgear according to claim 1 , wherein said semiconductor switch and said mechanical switch are connected to a common control power source. 10. The power switchgear according to any one of claims 2 to 9 , wherein adjacent semiconductor switches in a plurality of series-connected parallel-connected bodies are connected to a common control power source. . The mechanical switch has a pair of electrodes, and the pair of electrodes are provided so as to be separated,
2. The ON voltage of the semiconductor switch is lower than the lowest voltage at which the electron multiplication of the electron avalanche between the electrodes is 1 in the non-connected state where the pair of electrodes are spaced apart. 11. The power switchgear according to any one of 10 . A power transmission and distribution system comprising the power switchgear according to any one of claims 1 to 11 . A power generation system in which a power generation device is connected to a power system via the power switchgear according to any one of claims 1 to 11 . A load system in which a load is connected to a power system via the power switchgear according to any one of claims 1 to 11 . In a power switching device having a parallel-connected body of a mechanical switch and a semiconductor switch, the semiconductor switch is mounted on a metal body, and the heat capacity of the metal body on which the semiconductor switch is mounted is the same as the heat capacity and the semiconductor switch. A control method for a power switchgear, wherein a heat capacity value as a product of a temperature change due to an allowable temperature rise is set to a value greater than a heat quantity generated when the semiconductor switch is cut off,
The control unit controls the semiconductor switch to be in a connected state, and then controls the mechanical switch to be in a connected state, thereby shifting the power switchgear from the non-conducting state to the conducting state. Yes, and
The control unit maintains both the semiconductor switch and the mechanical switch in an ON state during the conduction state, and
After performing control to confirm that the semiconductor switch is on, the control unit performs control to disconnect the mechanical switch, and then performs control to turn off the semiconductor switch. Thus, the power switchgear is switched from the conducting state to the non-conducting state.
A control method for a power switchgear, characterized by:

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