JP2017200327A - Multi-terminal power transmission system - Google Patents

Abstract

A highly reliable multi-terminal power transmission system is provided. A multi-terminal power transmission system (100) is connected to a wind power plant (G1) via an AC circuit breaker (12) and to an AC / DC converter (11) connected to a DC power transmission network (Q) via a DC circuit breaker (13). A control device 14 for controlling the converter 11, an AC circuit breaker 12, a DC circuit breaker 13, and a central processing unit 40 for transmitting a command signal to the control device 14; a wind power plant G 1, G 2, and an AC system G3 is connected to the DC power transmission network Q, and the central processing unit 40 is connected to the AC / DC converters 11, 21, 31 and the control device by supplying power from the power system that can supply power among the wind power plants G1, G2 and the AC system G3. 14, 24, 34 are activated. [Selection] Figure 1

Description

  The present invention relates to a multi-terminal power transmission system.

  As a countermeasure when the power supply from the power system stops, for example, Patent Document 1 discloses that when the power transmission network is collapsed and the wind power plant is in a shutdown state, “the central power plant controller 5 is a local power source. 6 ”, it is possible to control the start-up and the self-start-up sequence by receiving power supply from“ 6 ”.

JP 2008-283856 A

  Patent Document 1 describes a countermeasure when a wind power plant is shut down in one-to-one power transmission between two power systems, but between three or more power systems. There is no description on how to deal with multi-terminal power transmission.

  The above-described multi-terminal power transmission is often performed, for example, in an offshore wind farm that transmits power from a wind power plant installed on the ocean to a land via a power conversion plant and a DC power transmission network. Even in such multi-terminal power transmission, it is desired that each device such as a power conversion station can be returned to a normal state when power supply from the power system is stopped.

  Therefore, an object of the present invention is to provide a highly reliable multi-terminal power transmission system.

  In order to solve the above-described problems, the present invention is characterized in that each of the power converters and the control device is activated by power supply from a power system that can supply power among three or more power systems.

  According to the present invention, a highly reliable multi-terminal power transmission system can be provided.

1 is a configuration diagram of a multi-terminal power transmission system according to a first embodiment of the present invention. It is a block diagram of the AC / DC converter with which the multi-terminal power transmission system which concerns on 1st Embodiment of this invention is provided. It is a flowchart which shows the flow of a process in the multiterminal power transmission system which concerns on 1st Embodiment of this invention. It is a flowchart which shows the flow of a process in the multiterminal power transmission system which concerns on 2nd Embodiment of this invention. It is a block diagram of the multi-terminal power transmission system which concerns on 3rd Embodiment of this invention. It is a block diagram of the multi-terminal power transmission system which concerns on 4th Embodiment of this invention. It is a block diagram of the multi-terminal power transmission system which concerns on 5th Embodiment of this invention. It is a block diagram of the AC-AC converter with which the multi-terminal power transmission system which concerns on 5th Embodiment of this invention is provided. It is a block diagram of the multi-terminal power transmission system which concerns on 6th Embodiment of this invention. It is a block diagram of the multi-terminal power transmission system which concerns on 7th Embodiment of this invention.

<< First Embodiment >>
<Configuration of multi-terminal power transmission system>
FIG. 1 is a configuration diagram of a multi-terminal power transmission system 100 according to the first embodiment.
In FIG. 1, the DC power transmission network Q (interconnection power transmission network) is illustrated by a thick solid line, and power lines such as the AC power transmission lines h1, h2, and h3 are illustrated by a thin solid line. In FIG. 1, “communication means” between the central processing unit 40 (processing unit) and each device is illustrated by broken lines. As the “communication means”, for example, an optical fiber may be used, or wireless communication may be performed.

  A multi-terminal power transmission system 100 shown in FIG. 1 is a system that performs multi-terminal power transmission between a wind power plant G1, G2 (power system) and an AC system G3 (power system) via a DC power transmission network Q or the like. As shown in FIG. 1, the wind power plant G1 sequentially passes through an AC circuit breaker 12 (first circuit breaker), an AC / DC converter 11 (power converter), and a DC circuit breaker 13 (second circuit breaker). It is connected to the DC power transmission network Q. The same applies to wind power plants G2 and AC systems G3, which are other “power systems”.

As shown in FIG. 1, the multi-terminal power transmission system 100 includes power conversion stations 10, 20, 30 and a central processing unit 40.
The power conversion station 10 is a facility that performs power conversion between the wind power plant G1 and the DC power transmission network Q. The AC side is connected to the wind power plant G1 via the AC power transmission line h1, and the DC side is DC power transmission. Connected to the network Q. As shown in FIG. 1, the power conversion station 10 includes an AC / DC converter 11, an AC circuit breaker 12, a DC circuit breaker 13, and a control device 14.

  The AC / DC converter 11 is a power converter that performs power conversion from one of AC power and DC power to the other. The AC / DC converter 11 has a function of converting AC power supplied from the wind power plant G1 into DC power and outputting the converted DC power to the DC power transmission network Q. Further, the AC / DC converter 11 converts the DC power supplied via the DC power transmission network Q into AC power when the wind power plant G1 is not generating power, and converts the converted AC power into the wind power plant. It also has a function of outputting to each G1 device (a control device and a power converter (not shown)).

FIG. 2 is a configuration diagram of the AC / DC converter 11 included in the multi-terminal power transmission system 100.
The AC / DC converter 11 is a two-level self-excited power converter, and includes a bridge circuit T and a capacitor N.
The bridge circuit T includes self-extinguishing switching elements S1 to S6 connected in a bridge shape, and free-wheeling diodes D1 to D6 connected in antiparallel to the switching elements S1 to S6, respectively.

The bridge circuit T includes a first leg in which switching elements S1 and S2 are connected in series, a second leg in which switching elements S3 and S4 are connected in series, and a third leg in which switching elements S5 and S6 are connected in series. The leg is connected in parallel. The connection point cu of the switching elements S1 and S2 is connected to the AC circuit breaker 12 (see FIG. 1) via the AC side terminal eu. The same applies to the other connection points cv and cw.
For example, IGBTs (Insulated G1te Bipolar Transistors) can be used as the self-extinguishing switching elements S1 to S6, but the invention is not limited thereto.

  The capacitor N smoothes the voltage applied from the bridge circuit T, and is connected in parallel to the DC side of the bridge circuit T. The positive electrode of the capacitor N is connected to the collectors of the switching elements S1, S3, and S5 of the upper arm, and is connected to the DC circuit breaker 13 (see FIG. 1) via the DC side terminal ea. The negative electrode of the capacitor N is connected to the emitters of the switching elements S2, S4, and S6 of the lower arm, and is connected to the DC circuit breaker 13 (see FIG. 1) via the DC side terminal ec.

  The control device 14 shown in FIG. 2 is a device that controls ignition / extinguishing of the switching elements S1 to S6 based on a command from the central processing unit 40 described later. The control device 14 also has a function of controlling the AC circuit breaker 12 and the DC circuit breaker 13 based on a command from the central processing unit 40.

  Although not shown, the control device 14 includes electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read out and expanded in the RAM, and the CPU executes various processes.

  As shown in FIG. 2, the control device 14 is connected in parallel to the capacitor N via the wiring k. Power is supplied to the control device 14 via the wiring k, and the control device 14 is activated. The activation of the control device 14 will be described later.

Returning again to FIG. 1, the description will be continued.
The AC circuit breaker 12 is a device that connects and disconnects the AC / DC converter 11 and the wind power plant G1. The DC circuit breaker 13 is a device that connects and disconnects the AC / DC converter 11 and the DC power transmission network Q. The AC circuit breaker 12 and the DC circuit breaker 13 are controlled by the control device 14. However, depending on the case, the AC circuit breaker 12 and the DC circuit breaker 13 may be controlled by the central processing unit 40 without going through the control device 14.

The AC side of the power conversion station 20 is connected to the wind power plant G2 via the AC power transmission line h2, and the DC side is connected to the DC power transmission network Q.
The power conversion station 30 has an AC side connected to the AC system G3 via an AC transmission line h3, and a DC side connected to the DC power transmission network Q.
In addition, about the structure of the power converter stations 20 and 30, since it is the same as that of the above-mentioned power converter station 10, description is abbreviate | omitted.

  The central processing unit 40 is a device that transmits predetermined command signals to the AC circuit breakers 12, 22, 32, the DC circuit breakers 13, 23, 33, and the control devices 14, 24, 34. Although not shown, the central processing unit 40 includes electronic circuits such as a CPU, ROM, RAM, and various interfaces. Then, the program stored in the ROM is read out and expanded in the RAM, and the CPU executes various processes. The processing executed by the central processing unit 40 will be described later.

<Processing in a multi-terminal power transmission system>
Next, a process for starting each device by power supply from the AC system G3 in a state where power generation is not performed at the wind power plants G1 and G2 and power is not supplied to the power conversion stations 10, 20, and 30 is illustrated in FIG. 3 will be described. Incidentally, when the power generation is not performed at the wind power plants G1 and G2, the windmill (not shown) is stopped or idle, or during the maintenance of the wind power plants G1 and G2.

FIG. 3 is a flowchart showing the flow of processing in the multi-terminal power transmission system 100 (see FIG. 1 as appropriate).
At the time of “system start-up” in step S101, as described above, the wind power plants G1 and G2 are not generating power, and the power converter stations 10, 20, and 30 (control devices 14, 24, and 34). It is assumed that no power is supplied. Further, the AC circuit breakers 12, 22, 32 and the DC circuit breakers 13, 23, 33 are all open.

  In step S101 of FIG. 3, the central processing unit 40 starts system activation. That is, the central processing unit 40 starts processing for starting each device of the power conversion stations 10, 20, and 30. For example, when it is determined that power is not supplied to the power conversion stations 10, 20, and 30 based on the detection values of various sensors (not shown) installed in the power conversion stations 10, 20, and 30, the central calculation The apparatus 40 starts system activation in step S101.

In step S <b> 102, the central processing unit 40 transmits a closing instruction to the AC circuit breaker 32 in order to activate each device of the power conversion station 30.
In step S103, the AC circuit breaker 32 is actually turned on by the above-described making command.

  When the AC circuit breaker 32 is thus turned on (S103), the AC / DC converter 31 and the like are started from the AC side in step S104. That is, the AC / DC converter 31 and the control device 34 are activated by the power supply from the AC system G3. Since the AC / DC converter 31 has the same configuration as the AC / DC converter 11 shown in FIG. 2, the activation of the AC / DC converter 31 and the like will be described below with reference to FIG. 2.

  Since the switching elements S1 to S6 shown in FIG. 2 are self-extinguishing type elements as described above, they are in the arc extinguishing state when the control device 34 (see FIG. 1) is not activated. Thereafter, the AC circuit breaker 32 is turned on (S103), and when AC power is supplied via the AC side terminals eu, ev, and ew shown in FIG. 2, the bridge circuit T included in the AC / DC converter 31 is converted into a three-phase diode rectifier. Function as. As a result, DC power is supplied to the control device 34 via the bridge circuit T, the capacitor N, and the wiring k, and the control device 34 is activated. Further, electric charge is stored in the capacitor N, and the voltage between the electrode plates of the capacitor N increases. In this way, the AC / DC converter 31 and the control device 34 are activated from the AC side.

  In step S105 of FIG. 3, the central processing unit 40 turns on the DC circuit breaker 33. As a result, power can be supplied from the AC system G3 to the power conversion stations 10 and 20 via the DC power transmission network Q.

In step S <b> 106, the control device 34 transmits an activation completion signal to the central processing unit 40. That is, the control device 34 notifies the central processing unit 40 that each device of the power conversion station 30 including itself has started.
Although omitted in FIG. 3, after the potential difference between the plates of the capacitor N (see FIG. 2) included in the AC / DC converter 31 reaches a predetermined value, the control device 34 switches the switching elements S1 to S6 (see FIG. 2). Starts switching.

  In step S107, the DC power transmission network Q is charged. For example, in the multi-terminal power transmission system 100, when the wind power plant G1 is installed on the ocean and transmits power to the land via the DC power transmission network Q, a submarine cable is often used as the DC power transmission network Q. Based on the charging capacity of DC power transmission network Q, central processing unit 40 stands by until the potential of DC power transmission network Q is stabilized in step S107.

Next, in step S <b> 108, the central processing unit 40 transmits a closing instruction to the DC circuit breaker 13 in order to activate each device of the power conversion station 10.
In step S109, the DC circuit breaker 13 is actually turned on in accordance with the above-described turn-on command.

  When the DC circuit breaker 13 is thus turned on (S109), the AC / DC converter 11 and the like are started from the DC side in step S110. That is, the AC / DC converter 11 and the control device 14 are activated by power feeding via the DC power transmission network Q.

  As shown in FIG. 2, the control device 14 of the AC / DC converter 11 is connected to the capacitor N in parallel. Therefore, when the DC circuit breaker 13 is turned on (S109), the capacitor N is charged and the AC / DC converter 11 is activated. Further, the control device 14 is activated by power feeding via the wiring k.

Next, in step S111 in FIG. 3, the central processing unit 40 turns on the AC circuit breaker 12. Thus, power is supplied to each device (a control device and a power converter (not shown)) of the wind power plant G1 through the AC power transmission line h1. As a result, it is possible to generate power at the wind power plant G1.
In step S112, the control device 14 transmits an activation completion signal to the central processing unit 40.

Next, in step S113, the central processing unit 40 transmits a closing instruction to the DC circuit breaker 23 in order to activate each device of the power conversion station 20.
In step S114, the DC circuit breaker 23 is actually turned on in accordance with the above-described making command.

When the DC circuit breaker 23 is thus turned on (S114), the AC / DC converter 21 and the like are started from the DC side in step S115. That is, the AC / DC converter 21 and the control device 24 are activated by power feeding via the DC power transmission network Q.
In step S116, the central processing unit 40 turns on the AC circuit breaker 22. As a result, power is supplied to each device of the wind power plant G2 via the AC power transmission line h2.
In step S117, the control device 24 transmits an activation completion signal to the central processing unit 40.

In this way, the central processing unit 40 is connected to the AC / DC converters 11, 21, 31 and the control devices 14, 24, 34 by supplying power from the AC system G 3 that can supply power among the wind power plants G 1, G 2 and the AC system G 3. Is activated (S104, S110, S115).
The central processing unit 40 supplies power to the wind power plant G1 from the AC system G3 that can supply power via the AC / DC converters 31 and 11 after startup (S101 to S112), and then AC / DC conversion after startup. Power is supplied to the wind power plant G2 through the devices 31 and 21 (S113 to S117). In this way, power is sequentially supplied to the wind power plants G1 and G2.

In step S118, the central processing unit 40 determines that the activation of each device has been completed in all of the power conversion stations 10, 20, and 30 (all sites have been activated).
In step S119, the central processing unit 40 completes system startup. That is, the central processing unit 40 completes activation of each device of the multi-terminal power transmission system 100.

  In addition, after starting of each apparatus of the multi-terminal power transmission system 100 is completed, power is exchanged between the wind power plants G1 and G2 and the AC system G3 based on, for example, well-known power flow calculation.

<Effect>
According to 1st Embodiment, since each apparatus of the power converter station 10, 20, 30 can be started by the electric power feeding from AC system | strain G3, the reliability of the multi-terminal power transmission system 100 can be improved rather than before.

  In addition, since it is not necessary to provide a starting power source (not shown) such as a power storage device in the power conversion stations 10, 20, 30 and the wind power plants G1, G2, the facility cost can be reduced as compared with the conventional case. For example, when the wind power plants G1 and G2 are offshore wind farms installed on the ocean, it is desirable that the number of start-up power supplies (not shown) is small from the viewpoint of equipment area and equipment cost. According to this embodiment, since each apparatus of the power converter station 10, 20, 30 can be started from AC system | strain G3 which can supply electric power, the installation area and installation cost of an offshore wind farm can be small.

  The control device 14 (see FIG. 2) is connected in parallel to the DC side of the self-excited AC / DC converter 11. Therefore, as described above, the control device 14 can be activated by power feeding from the AC side of the AC / DC converter 11, or the control device 14 can be activated by power feeding from the DC side of the AC / DC converter 11. it can. The same applies to the activation of the other control devices 24 and 34. Thus, for example, if power can be supplied from at least one of the three power systems (wind power plants G1, G2 and AC system G3), power can be supplied to other power systems using the AC / DC converters 11, 21, 31. it can.

<< Second Embodiment >>
The second embodiment is different from the first embodiment in that power is not sequentially supplied to the wind power plants G1 and G2 (see FIG. 1), but these are performed in parallel. The configuration and the like of the power transmission system 100 (see FIG. 1) are the same as those in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

FIG. 4 is a flowchart showing a process flow in the multi-terminal power transmission system 100 according to the second embodiment (refer to FIG. 1 as appropriate).
Note that the processing in steps S101 to S107 in FIG. 4 is the same as that in the first embodiment (see FIG. 3), and thus the description thereof is omitted.
After the DC power transmission network Q is charged in step S107, the central processing unit 40 transmits a closing command to the DC circuit breaker 13 and also transmits a closing command to the DC circuit breaker 23 in step S201.

  Thereafter, for the power conversion station 10, the DC circuit breaker 13 is turned on (S109), the AC / DC converter 11 is activated from the DC side (S110), and the AC circuit breaker 12 is turned on (S111). An activation completion signal is transmitted to the central processing unit 40 (S112). The same applies to the other power conversion station 20 (S114 to S117). In this way, the central processing unit 40 feeds power from the AC system G3 capable of feeding power to the wind power plant G1 via the AC / DC converters 31 and 11 after startup, and via the AC / DC converters 31 and 21 after startup. Power supply to the wind power plant G2 is performed in parallel. As a result, the time required to start each device of the AC / DC converter station 10 or 20 can be shortened compared to the first embodiment.

  In FIG. 4, after receiving the activation completion signals (S112, S117) from the control devices 14, 24, the central processing unit 40 assumes that the activation of each device has been completed in all of the power conversion stations 10, 20, 30. Determination is made (S118), and the system startup is completed (S119).

<Effect>
According to the second embodiment, power feeding to the power conversion station 10 and the wind power plant G1 and power feeding to the power conversion plant 20 and the wind power plant G2 are performed in parallel (S201, S109 to S117). Therefore, the time required for starting each device can be shortened as compared with the first embodiment in which these power supplies are sequentially performed.

«Third embodiment»
In the third embodiment, when a power failure or the like occurs in the AC system G3 (see FIG. 5), power cannot be supplied from the AC system G3, and power generation is not performed in the wind power plants G1 and G2, the startup power supply P3 ( The point which starts each apparatus by the electric power feeding from FIG. 5) differs from 1st Embodiment. Other points are the same as in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

FIG. 5 is a configuration diagram of a multi-terminal power transmission system 100A according to the third embodiment.
The multi-terminal power transmission system 100A has a configuration in which a startup power supply P3 and an AC circuit breaker K3 (third circuit breaker) are added to the configuration described in the first embodiment (see FIG. 1). As shown in FIG. 5, the power conversion station 30 </ b> A includes an AC / DC converter 31, an AC circuit breaker 32, a DC circuit breaker 33, a control device 34, a starting power source P <b> 3, and an AC circuit breaker K <b> 3. Yes.

  The start power source P3 is a power source for a power storage device, a diesel generator, or the like. When a power storage device is used as start-up power supply P3, it is assumed that a power converter (not shown) that converts DC power supplied from the power storage device into AC power is separately provided.

  The AC circuit breaker K3 is a device that connects and disconnects the AC / DC converter 31 and the starting power supply P3. In the example shown in FIG. 5, an AC circuit breaker K <b> 3 is connected to a three-phase wiring i that connects the AC / DC converter 31 and the AC circuit breaker 32. The AC circuit breaker K3 is controlled by a command signal from the central processing unit 40.

  In the case where a power failure or the like occurs in the AC system G3 shown in FIG. 5 and power supply is stopped, and in the wind power plants G1 and G2, the central processing unit 40 inputs the AC circuit breaker K3. In addition, when using a diesel generator as starting power supply P3, after starting this diesel generator, the central processing unit 40 throws in AC circuit breaker K3.

  When the AC circuit breaker K3 is turned on, power is supplied from the activation power source P3 to the AC / DC converter 31 and the control device 34 via the AC circuit breaker K3, and these devices are activated. Thereafter, the central processing unit 40 sequentially performs the processing of steps S105 to S119 described in the first embodiment (see FIG. 3). As a result, power is supplied to the AC / DC converters 11 and 21 and the control devices 14 and 24 in addition to the AC / DC converter 31 and the control device 34 described above, and these devices are activated. In addition, power is supplied to each of the wind power plants G1 and G2. After each device of the wind power plants G1 and G2 is activated to generate power, the central processing unit 40 opens the AC circuit breaker K3 and turns on the AC circuit breaker 32. As a result, the power generated by the wind power plants G1 and G2 is supplied to the AC system G3.

  Prior to power supply to the wind power plants G1 and G2, the AC system G3 may be restored first by supplying power to the AC system G3 from the starting power supply P3 via the AC circuit breaker K3 and the AC circuit breaker 32. After restoration of the AC system G3, the central processing unit 40 opens the AC circuit breaker K3, and further sequentially performs the processing of steps S105 to S119 described in the first embodiment (see FIG. 3). As a result, the power from the restored AC system G3 can be supplied to each device of the wind power plants G1 and G2, and the power can be returned to a state where power can be generated at the wind power plants G1 and G2.

<Effect>
According to the third embodiment, even in a situation where a power failure or the like occurs in the AC system G3 and power generation is not performed in the wind power plants G1 and G2, the power conversion stations 10, 20, 30A and the like are used using the startup power source P3. You can power up and activate each device.

<< Fourth Embodiment >>
In the fourth embodiment, instead of the power conversion station 30A (see FIG. 5), the power conversion station 10B (see FIG. 6) connected to the wind power station G1 is connected to the start power source P1 and the AC circuit breaker K1 (third). The point which provides the circuit breaker differs from 3rd Embodiment. Other points are the same as in the third embodiment. Therefore, a different part from 3rd Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

FIG. 6 is a configuration diagram of a multi-terminal power transmission system 100B according to the fourth embodiment.
As shown in FIG. 6, the power conversion station 10 </ b> B includes an AC / DC converter 11, an AC circuit breaker 12, a DC circuit breaker 13, a control device 14, a starting power supply P <b> 1, and an AC circuit breaker K <b> 1. Yes.

The starting power source P1 is a power source for a power storage device, a diesel generator, or the like.
The AC circuit breaker K1 is a device that connects and disconnects the AC / DC converter 11 and the starting power supply P1. In the example shown in FIG. 6, an AC circuit breaker K <b> 1 is connected to a three-phase wiring j that connects the AC / DC converter 11 and the AC circuit breaker 12. The AC circuit breaker K1 is controlled by a command signal from the central processing unit 40.

  Assume that a power failure or the like occurs in the AC system G3 shown in FIG. 6 and power supply stops, and that no power generation is performed in the wind power plants G1 and G2. In such a case, the central processing unit 40 activates the activation power source P1 (for example, a diesel generator), and further turns on the AC circuit breaker K1. Thereby, the AC / DC converter 11 and the control device 14 are activated from the AC side. Then, the central processing unit 40 turns on the DC circuit breakers 13, 23, and 33, and activates each device of the power conversion stations 20 and 30 from the DC side. Thus, after starting each apparatus of power converter station 10B, 20, and 30, after restoring AC system | strain G3, you may supply electric power to wind power plant G1, G2, or wind power plant G1, The power may be supplied to the AC system G3 after generating power with G2.

<Effect>
According to the fourth embodiment, even in a situation where a power failure or the like occurs in the AC system G3 and power generation is not performed in the wind power plants G1 and G2, the power conversion stations 10B, 20, 30 and the like are used using the startup power supply P1. You can power up and activate each device.

«Fifth embodiment»
In the fifth embodiment, the AC-AC conversion is performed at the power conversion stations 10C, 20C, and 30C (see FIG. 7), and the “connected power transmission network” connected to the power conversion stations 10C, 20C, and 30C is AC transmission. The point which is the net | network R differs from 1st Embodiment. Other points are the same as in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

FIG. 7 is a configuration diagram of a multi-terminal power transmission system 100C according to the fifth embodiment.
As illustrated in FIG. 7, the multi-terminal power transmission system 100C includes power conversion stations 10C, 20C, and 30C, and a central processing unit 40.

  The power conversion station 10C is a facility that performs power conversion between the wind power plant G1 and the AC power transmission network R. As shown in FIG. 7, the power conversion station 10C includes an AC-AC converter 15 (power converter), an AC circuit breaker 12 (first circuit breaker), an AC circuit breaker 16 (second circuit breaker), And a control device 14.

  The AC-AC converter 15 is a two-level self-excited power converter that changes the voltage and current of AC power input to itself and outputs the AC power after the change. The AC-AC converter 15 has a function of converting AC power supplied from the wind power plant G1 into AC power having a predetermined voltage and current, and outputting the converted AC power to the AC power transmission network R. Yes. Further, the AC-AC converter 15 converts AC power supplied to itself via the AC power transmission network R into AC power of a predetermined voltage and current when power generation is not performed at the wind power plant G2. Also, it has a function of outputting the converted AC power to each device of the wind power plant G1.

FIG. 8 is a configuration diagram of the AC-AC converter 15 provided in the multi-terminal power transmission system 100C. As shown in FIG. 8, the AC-AC converter 15 includes an AC / DC converter 151 (first AC / DC converter) and an AC / DC converter 152 (second AC / DC converter).
The AC / DC converter 151 is a power converter that performs conversion from one of AC power and DC power to the other. More specifically, the AC / DC converter 151 is a self-excited two-level converter that includes a plurality of self-extinguishing switching elements (not shown) and a capacitor (not shown), and is a first embodiment. The configuration is the same as that of the AC / DC converter 11 (see FIG. 2) described above. The same applies to the other AC / DC converter 152.

As shown in FIG. 8, the AC side of the AC / DC converter 151 is connected to the wind power plant G <b> 1 (power system: power supply) via the three-phase AC connection terminal fe and the AC circuit breaker 12 (first circuit breaker: see FIG. 7). (See FIG. 7).
The DC side of the AC / DC converter 151 is connected to the DC side of the other AC / DC converter 152.
The AC side of the AC / DC converter 152 is connected to the AC power transmission network R (interconnection power transmission network: see FIG. 7) via the three-phase AC connection terminal ge and the AC circuit breaker 16 (second circuit breaker: see FIG. 7). It is connected.

  The control device 14 illustrated in FIG. 8 has a function of controlling the AC / DC converters 151 and 152 and the like. The control device 14 is connected in parallel to the DC side of the AC / DC converter 151 via the wiring n, and is also connected in parallel to the DC side of the AC / DC converter 152 via the wiring n.

  The AC circuit breaker 16 shown in FIG. 7 is a device that connects and blocks the AC-AC converter 15 and the AC power transmission network R. The AC circuit breaker 16 is controlled by the central processing unit 40 and the control device 14 after activation. Since the other power conversion stations 20C and 30C have the same configuration as the power conversion station 10C, the description thereof is omitted.

  For example, when the power generation is not performed at the wind power plants G1 and G2, and the power conversion stations 10C, 20C, and 30C are not supplied with power, the central processing unit 40 performs processing similar to that in the first embodiment (see FIG. 3). )I do. As a result, power from the AC system G3 is supplied to the control device 14 through the power conversion station 30C, the AC power transmission network R, the AC circuit breaker 16, and the wiring n shown in FIG. to start. In addition, capacitors (not shown) included in the AC / DC converters 151 and 152 are charged. In this way, each device in the power conversion station 10C is activated, and each device in the power conversion stations 20C and 30C is also activated. In addition, power is supplied to each of the wind power plants G1 and G2.

<Effect>
According to the fifth embodiment, even when the AC power transmission network R is used as the “connected power transmission network”, each device of the power conversion stations 10C, 20C, 30C and the wind power plants G1, G2 is fed by power supply from the AC system G3. Can be started. In addition, since the above-described start-up can be performed without providing a start-up power source (not shown) in the wind power plants G1, G2, etc., the equipment area and equipment costs of the wind power plants G1, G2 can be reduced as compared with the conventional one. .

<< Sixth Embodiment >>
The sixth embodiment is different from the first embodiment in that DC-DC conversion is performed in the power conversion stations 10D and 20D (see FIG. 9), but the other points are the same as those in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

FIG. 9 is a configuration diagram of a multi-terminal power transmission system 100D according to the sixth embodiment.
As illustrated in FIG. 9, the multi-terminal power transmission system 100D includes power conversion stations 10D, 20D, and 30 and a central processing unit 40.

  The power conversion station 10D includes a DC-DC converter 17 (power converter), a DC circuit breaker 18 (first circuit breaker), a DC circuit breaker 13 (second circuit breaker), a switching circuit 19, and a power meter. W11 (first wattmeter), wattmeter W12 (second wattmeter), and control device 14 are provided.

The DC-DC converter 17 is a well-known self-excited power converter that changes the voltage and current of DC power input to itself and outputs the DC power after the change.
The DC breaker 18 is a device for connecting / cutting off the DC-DC converter 17 and the wind power plant G1.

  Whether the switching circuit 19 supplies power to the control device 14 from the wind power plant G1 via the DC circuit breaker 18, or supplies power to the control device 14 via the DC power transmission network Q and the DC circuit breaker 13. Is a circuit for switching between. As shown in FIG. 9, the switching circuit 19 is connected to the control device 14 and also connected to the input side and output side of the DC-DC converter 17.

  The wattmeter W11 detects power supplied from the wind power plant G1 to the DC-DC converter 17. In the example shown in FIG. 9, a wattmeter W11 is connected to a wiring q that connects the DC-DC converter 17 and the DC circuit breaker 18. The detection value of the wattmeter W11 is transmitted to the central processing unit 40.

  The wattmeter W12 detects power supplied to the DC-DC converter 17 via the DC power transmission network Q. In the example shown in FIG. 9, a wattmeter W <b> 12 is connected to a wiring r that connects the DC-DC converter 17 and the DC circuit breaker 13. The detected value of the wattmeter W12 is transmitted to the central processing unit 40.

  The power conversion station 20D has the same configuration as the above-described power conversion station 10D, and the power conversion station 30 is the same as that described in the first embodiment (see FIG. 1). The description of is omitted. By the way, although not shown in figure, the AC / DC converter which converts alternating current power (generated power) into direct current power is provided in the wind power plants G1 and G2.

Next, a process for supplying power to the control device 14 via the switching circuit 19 will be described.
Although power can be supplied from at least one of the wind power plants G1, G2 and the AC system G3, when the power is not supplied to each device of the power conversion station 10D, the central processing unit 40 executes the following processing. That is, the central processing unit 40 detects whether the power meters W11 and W12 can supply power to the control device 14 from the wind power plant G1 or whether it can supply power to the control device 14 via the DC power transmission network Q. Determine based on the value. It is assumed that the DC breakers 13 and 18 are turned on when making this determination.

  Then, the central processing unit 40 controls the switching circuit 19 so that power is supplied to the control device 14 based on the result of the determination described above. As a result, power is supplied to the control device 14 via the switching circuit 19 and the control device 14 is activated. The same applies to the activation of the control device 24 included in the other power conversion station 20D.

<Effect>
According to the sixth embodiment, even in a configuration that performs DC-DC conversion in the power conversion stations 10D, 20D, for example, the power conversion stations 10D, 20D, 30 and the wind power station G1, using the power from the AC system G3. Each device of G2 can be activated. Moreover, since direct current power transmission is performed between the wind power plant G1 and the power conversion plant 10D, or between the wind power plant G2 and the power conversion plant 20D, the loss associated with power transmission compared with the case of performing alternating current power transmission. Can be reduced.

<< Seventh Embodiment >>
The seventh embodiment differs from the first embodiment in that a starting power source PE (see FIG. 10) connected to the DC power transmission network Q via a DC breaker KE (fourth breaker: see FIG. 10) is provided. However, other aspects are the same as in the first embodiment. Therefore, a different part from 1st Embodiment is demonstrated and description is abbreviate | omitted about the overlapping part.

FIG. 10 is a configuration diagram of a multi-terminal power transmission system 100E according to the seventh embodiment.
As shown in FIG. 10, the multi-terminal power transmission system 100E includes power conversion stations 10, 20, and 30, a central processing unit 40, a starting power source PE, and a DC circuit breaker KE.

The starting power source PE is a power source for a power storage device, a diesel generator, or the like.
The DC circuit breaker KE is a device that connects and disconnects the DC power transmission network Q and the starting power source PE. The DC circuit breaker KE is controlled by a command signal from the central processing unit 40.

  For example, it is assumed that a power failure or the like occurs in the AC system G3 illustrated in FIG. 10 and power supply is stopped, and that no power generation is performed in the wind power plants G1 and G2. In such a case, the central processing unit 40 turns on the DC circuit breaker KE and turns on the DC circuit breakers 13, 23, and 33 (second circuit breaker).

  For example, when the DC breakers KE and 13 are turned on, power is supplied from the starting power supply PE to the AC / DC converter 11 and the control device 14 via the DC breaker KE and the like. As a result, the AC / DC converter 11 and the control device 14 are activated. The same applies to the activation of each device in the power conversion stations 20 and 30.

<Effect>
According to the seventh embodiment, even in a situation where a power failure or the like occurs in the AC system G3 and power generation is not performed in the wind power plants G1 and G2, the power conversion stations 10, 20, 30 and the like are used using the startup power source PE. You can power up and activate each device.

≪Modification≫
As described above, the multi-terminal power transmission system 100 and the like according to the present invention have been described by the respective embodiments, but the present invention is not limited to these descriptions, and various modifications can be made. For example, in each embodiment, although each power converter (For example, the AC / DC converters 11, 12, and 13 shown in FIG. 1) was a self-excited 2 level converter, it was not restricted to this. That is, as each power converter, a self-excited three-level converter or a modular multi-level converter may be used. Even in such a configuration, by connecting the control device in parallel to the DC side of the power converter, power can be supplied to the control device from either the DC side or the AC side, and this control device can be activated.

  Further, in each embodiment, a configuration in which three “power systems” (wind power plants G1, G2 and AC system G3) are connected to a “connected power transmission network” (for example, the DC power transmission network Q shown in FIG. 1). Although explained, it is not limited to this. That is, each embodiment can also be applied to a configuration in which four or more power systems are connected to the interconnection grid.

  Moreover, although 3rd Embodiment demonstrated the structure which connects the starting power supply P3 via AC circuit breaker K3 to the wiring i which connects the AC / DC converter 31 (refer FIG. 5) and AC circuit breaker 32, this Not limited to. That is, the starting power supply P3 may be connected to the wiring connecting the AC / DC converter 31 and the DC circuit breaker 33 via an AC circuit breaker (not shown). The same applies to the fourth embodiment (see FIG. 6).

  Moreover, although each embodiment demonstrated the case where IGBT was used as the self-extinguishing type | mold switching element S1-S6 (refer FIG. 2) used for the AC / DC converter 11 grade | etc., It does not restrict to this. That is, for example, FETs (Field Effect Transistors) and bipolar transistors may be used as the self-extinguishing type switching elements S1 to S6.

  Moreover, each embodiment can be combined suitably. For example, when the second embodiment and the third embodiment are combined and power is supplied to each device of the multi-terminal power transmission system 100A (see FIG. 5) from the startup power supply P3 (third embodiment), the AC / DC converter 11 is used. Power feeding to the wind power plant G1 and power feeding to the wind power plant G2 via the AC / DC converter 21 may be performed in parallel (second embodiment).

  Each embodiment is described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the described configurations. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of the embodiment. In addition, the above-described mechanisms and configurations are those that are considered necessary for the description, and do not necessarily indicate all the mechanisms and configurations on the product.

  In addition, power lines and signal lines are those that are considered necessary for explanation, and not all power lines and signal lines are necessarily shown in the product. Actually, it may be considered that almost all the components are connected to each other.

100, 100A, 100B, 100C, 100D, 100E Multi-terminal power transmission system 11, 21, 31 AC / DC converter (power converter)
T bridge circuit S1, S2, S3, S4, S5, S6 switching element D1, D2, D3, D4, D5, D6 freewheeling diode N capacitor 12, 22, 32 AC circuit breaker (first circuit breaker)
13, 23, 33 DC breaker (second breaker)
14, 24, 23 Control device 15 AC-AC converter (power converter)
151 AC / DC converter (first AC / DC converter)
152 AC / DC converter (second AC / DC converter)
16 AC circuit breaker (second circuit breaker)
17 DC-DC converter (power converter)
18 DC circuit breaker (first circuit breaker)
19 switching circuit 40 central processing unit (processing unit)
G1, G2 Wind farm (electric power system)
G3 AC system (power system)
K1, K3 AC circuit breaker (third circuit breaker)
KE DC circuit breaker (4th circuit breaker)
P1, P3, PE Start-up power supply Q DC transmission network (interconnection transmission network)
R AC transmission network (interconnection grid)
W11 power meter (first power meter)
W12 power meter (second power meter)
k wiring n wiring

Claims (8)

A power converter connected to the power system via the first circuit breaker and connected to the grid transmission network via the second circuit breaker;
A control device for controlling the power converter;
An arithmetic unit that transmits a command signal to the first circuit breaker, the second circuit breaker, and the control device;
Three or more of the power systems are connected to the interconnected power grid through the first circuit breaker, the power converter, and the second circuit breaker, respectively,
The arithmetic device starts each of the power converter and the control device by feeding power from a power system that can feed power among three or more power systems. The power converter is
An AC / DC converter that performs power conversion from one of AC power and DC power to the other,
A bridge circuit having a plurality of self-extinguishing switching elements connected in a bridge shape, and a plurality of free-wheeling diodes connected in antiparallel to each of the plurality of switching elements;
A capacitor connected in parallel to the DC side of the bridge circuit,
The multi-terminal power transmission system according to claim 1, wherein the control device is connected in parallel to the capacitor via a wiring and is activated by the power feeding via the wiring. The power converter is
It is an AC-AC converter that changes the voltage and current of AC power input to itself and outputs the AC power after the change,
A first AC / DC converter that converts AC power and DC power from one to the other;
A second AC / DC converter that performs conversion from one of DC power and AC power to the other; and
The first AC / DC converter and the second AC / DC converter are respectively
A bridge circuit having a plurality of self-extinguishing switching elements connected in a bridge shape, and a plurality of free-wheeling diodes connected in antiparallel to each of the plurality of switching elements;
A capacitor connected in parallel to the DC side of the bridge circuit,
The AC side of the first AC / DC converter is connected to the power system via the first circuit breaker,
The DC side of the first AC / DC converter is connected to the DC side of the second AC / DC converter,
The AC side of the second AC / DC converter is connected to the interconnection power grid via the second circuit breaker,
The control device is connected in parallel to the DC side of the first AC / DC converter via wiring, and is also connected in parallel to the DC side of the second AC / DC converter via the wiring, via the wiring The multi-terminal power transmission system according to claim 1, wherein the multi-terminal power transmission system is activated by the power feeding. Whether to supply the power to the control device from the power system via the first circuit breaker, or to perform the power supply to the control device via the interconnection network and the second circuit breaker, A switching circuit for switching between,
A first wattmeter that detects power supplied from the power system to the power converter that is a control target of the control device;
A second wattmeter that detects power supplied to the power converter, which is a control target of the control device, via the interconnection power grid,
The power converter is a DC-DC converter that changes the voltage and current of DC power input to itself and outputs the DC power after the change,
The arithmetic device controls the switching circuit so that the power is supplied to the control device based on the detection value of the first wattmeter and the detection value of the second wattmeter, and The multi-terminal power transmission system according to claim 1, wherein the control device is activated by the supplied power. The arithmetic device sequentially supplies power to a plurality of other power systems from the power system that can supply power among the three or more power systems via the power converter after startup. The multi-terminal power transmission system according to any one of claims 1 to 4. The arithmetic device performs power feeding in parallel to the plurality of other power systems from the power system that can be fed out of the three or more power systems via the power converter after startup. The multi-terminal power transmission system according to any one of claims 1 to 4. A power converter connected to the power system via the first circuit breaker and connected to the grid transmission network via the second circuit breaker;
A control device for controlling the power converter;
An arithmetic device that transmits a command signal to the first circuit breaker, the second circuit breaker, and the control device, and transmits a command signal to a third circuit breaker that connects and disconnects the power converter and the starting power source. And comprising
Three or more of the power systems are connected to the interconnected power grid through the first circuit breaker, the power converter, and the second circuit breaker, respectively,
The computing device activates each of the power converter and the control device by power feeding from the activation power source through the third circuit breaker. A power converter connected to the power system via the first circuit breaker and connected to the grid transmission network via the second circuit breaker;
A control device for controlling the power converter;
An operation for transmitting a command signal to the first circuit breaker, the second circuit breaker, and the control device, and for transmitting a command signal to a fourth circuit breaker that connects and disconnects the interconnection power grid and the starting power source. An apparatus,
Three or more of the power systems are connected to the interconnected power grid through the first circuit breaker, the power converter, and the second circuit breaker, respectively,
The computing device activates each of the power converter and the control device by feeding power from the activation power source through the fourth circuit breaker.

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