JPH10304570A - Electric power system stabilizing method and electric power system stabilization equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a continuous system of small transmission loss in normal times, and stabilize the system at the time of an accident. SOLUTION: In normal times, breakers 20, 25, 23, 26 are closed, and breakers 21, 22, 24, 27 are opened, thereby constituting an AC continuous system. When a system accident is generated, breakers 21, 27 are closed, breakers 23, 25 are opened, BTB converters 10, 11 are started, and a DC continuous system is constituted. A stabilization control equipment 12 controls the BTB converters 10, 11, on the basis of frequency data of both systems. As a result, electric power necessary to maintain the system frequency is supplied, and the system is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for stabilizing a power system when a system fault occurs in a power system in which a plurality of power systems are interconnected by DC transmission or AC transmission. .

[0002]

2. Description of the Related Art FIG. 13 is a block diagram showing a conventional interconnection between power systems, for example, disclosed in Japanese Patent Application Laid-Open No. 7-67257. In the figure, 1 is a power system A, 2 is a power system B, 3 is a BTB converter (converter for DC transmission interconnection) incorporated in a BTB (DC transmission interconnection) configuration, 4 is a system stabilizer, 5 , 6 are system information, and 7 is a BTB power transmission amount command value.

Next, the operation will be described. For example, when it is considered that an accident occurs in the power system B2, the stability of the system is insufficient, and the system may collapse, the system information 5 and 6 obtained from the power system A1 and the power system B2 are used as the system stabilizing device 4.
To obtain the command value 7 of the transmission power of the BTB by calculation, and to transmit the power from the power system A1 to the power system B2 via the BTB3 to the power system B2 to maintain the stability of the system. .

However, for example, when an accident occurs in the power system B2 and the power becomes insufficient, the power system
The stabilization is achieved by receiving the power exchange through the TB converter 3. However, the power system A1 has the power interchange to assist the power system B even though there is no system accident, and the power system A1 has its own system. Cause unnecessary upset,
There was a risk that the system could collapse, and there was a limitation that too much power could not be interchanged.

[0005] Further, the power system B2
If the power to be transmitted is modulated to stabilize
The power system A1 also has a disadvantage that the power system is similarly shaken. Furthermore, since power is transmitted from the normal state via the BTB converter 3, there is a disadvantage that power transmission efficiency is poor due to loss of the converter.

[0006]

Since the conventional system stabilizing device is constructed as described above, the BTB can be used in normal times.
In addition to the converter loss, there is a problem that the effect cannot be exerted at the time of a large-scale accident, such as the fact that the power system to be assisted and the power system to be assisted are subjected to the same fluctuation, so that there is not much power interchange.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. In an ordinary situation, the system is interconnected by an AC interconnection line, and when an accident occurs, the interconnection by DC and the interconnection by AC are performed. It is an object to provide a device that can easily switch to a combined configuration and transmit power.

[0008]

[Means for Solving the Problems]

(1) A method for stabilizing a power system according to the present invention provides a method for stabilizing an AC system in a normal state by connecting an AC system to an AC system adjacent to each other and a DC system using DC transmission equipment. In the event of an accident, the AC system is separated and the DC system is connected so as to transfer power and suppress system fluctuation.

(2) In addition, the AC system is normally connected to an AC system that can perform AC interconnection with an adjacent AC system and DC interconnection with a plurality of DC transmission facilities, and the AC system is in the event of an AC system accident. In addition to separating the AC system, at least one of the DC transmission facilities is used for DC interconnection, and at least one of the other DC transmission facilities is used to suppress system fluctuation in the accident system. Things.

(3) In addition, the AC system is normally connected to an AC system adjacent to each other, which can perform AC interconnection and DC interconnection with a plurality of DC power transmission facilities, and in the event of an AC system failure, In addition, the AC system is separated, and at least one of the DC power transmission facilities is used for each of the AC systems to suppress system fluctuation in each of the systems.

(4) In addition, an AC system is normally connected to an AC system that can perform AC interconnection and a DC interconnection with a DC power transmission facility with respect to adjacent AC systems. The above-mentioned DC transmission equipment is used while the system is connected to control the system fluctuation in the accident system.

(5) In addition, an AC system is normally connected to an AC system that can perform AC interconnection to an adjacent AC system and DC interconnection with a DC power transmission facility. After the interconnection, the AC system was separated, and then the AC system was separated using the DC transmission equipment that was DC-connected,
Alternatively, the system swing is suppressed.

(6) In addition, AC power is normally connected to an AC system that can perform AC interconnection to an adjacent AC system and DC interconnection by a plurality of DC transmission facilities, In addition, the AC system is separated, and the DC interconnection is performed by using one or a plurality of DC power transmission facilities according to the power exchanged between the AC systems.

(7) The above (1) to (3),
In the power system stabilization method according to any one of (5) and (6), when the separated AC system is AC-connected again,
DC power is connected using DC power transmission equipment, the power flow is controlled, the phases of both power systems are matched, and a transition is made to AC connection.

(8) The power system stabilizing device according to the present invention has two connection points, a first connection point and a second connection point, respectively. In the configured power system, a series body of the switching means, the DC power transmission equipment, and the switching means is connected between the first connection point and the second connection point of the AC systems, and Switching means is connected between one connection point and the AC system B side terminal of the second connection point side DC power transmission equipment, and the second
Opening / closing means is connected between a connection point and an AC system B terminal of the first connection point side DC power transmission facility, and a first connection point of the AC system B and the AC system A of the second connection point side DC power transmission facility are connected. A switching circuit is connected between the second terminal of the AC system B and the AC system A side terminal of the first connection point side DC power transmission equipment to constitute a circuit; And control means for controlling the opening and closing of the switching means and the operation of the DC power transmission equipment, thereby performing AC interconnection, DC interconnection, and system fluctuation suppression.

(9) In the power stabilizing apparatus of (8), the control means is means for performing the power system stabilizing method of at least one of the above (1) to (4). is there.

(10) In a power system having two connection points of a first connection point and a second connection point, each of which is composed of an AC system A and an AC system B adjacent to each other, A series body of the switching means, the DC power transmission equipment, and the switching means is connected between the first connection point and the second connection point of the AC systems, and the first connection point of the AC system B and the second connection point. Switching means is connected between an AC system A side terminal of the DC power transmission equipment and a switching means between a second connection point of the AC system B and the AC system A terminal of the first connection point DC power transmission equipment. And by controlling the opening and closing of the switching means and the operation of the DC power transmission equipment, AC interconnection,
It is provided with control means for performing DC interconnection and system fluctuation suppression.

(11) In the power stabilizing apparatus according to the above (10), the control means comprises the above (1), (2),
(4) A means for performing the power system stabilization method according to at least one of (4).

(12) In a power system having two connection points of a first connection point and a second connection point, each of which is composed of an AC system A and an AC system B adjacent to each other, A circuit comprising a series body of switching means, DC power transmission equipment and switching means, and switching means connected in parallel to the series body is connected to each of a first connection point and a second connection point between the two AC systems, Opening / closing means is connected between the AC system A terminal of the first connection point side DC power transmission facility and the AC system A terminal of the second connection point side DC power transmission facility, and the first connection point side DC power transmission facility A circuit in which switching means is connected between the AC system B side terminal and the AC system B terminal of the second connection point side DC power transmission equipment is configured, and the opening and closing of the switching means and the operation of the DC power transmission equipment are controlled. AC connection, DC connection, system fluctuation suppression Those having a control means for performing.

(13) In the power stabilizing apparatus of (12), the control means is means for performing the power system stabilizing method of at least one of (5) and (6). is there.

(14) The method for stabilizing a power system according to the present invention provides a method for stabilizing an AC system in a normal state in a power system in which AC connection and DC connection by DC transmission equipment can be performed between three or more AC systems. However, in the event of an AC system accident, the DC power transmission equipment is used to stabilize the system by performing at least one of the interchange of power and the suppression of system fluctuation by using the DC transmission equipment between the desired AC systems. .

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a power system stabilizing device according to Embodiment 1 of the present invention. In the figure, 1 is a power system A, 2 is a power system B, and has first connection points 101 and 201 and second connection points 102 and 202. 10 and 11 are BTB conversion or DC power transmission equipment,
12 is a system stabilization control device, 13 and 14 are system information, 1
5 is a control signal, 20, 21, 22, 23, 24, 25,
Reference numerals 26 and 27 denote switches such as circuit breakers. FIG. 2 is a block diagram showing an example of a normal AC interconnection state, and the connection points shown in FIG. 1 are omitted. (Connection points are also omitted in the following block diagrams.) FIG. 3 is a diagram showing an example in which a DC link is changed to a DC link at the time of a system failure.

Next, the operation will be described. In normal times, as shown in FIG. 2, circuit breakers 20, 23, 25, and 26 are turned on to connect power system A1 and power system B2 by AC interconnection.

Now, for example, if an accident occurs in the AC system B2, system information 13 and 14 from each system are input to the system stabilization control device 12, and power is exchanged from the AC system A1 to the power system B2. If it is determined that it is necessary, a closing command is issued to the circuit breakers 21 and 27,
By issuing an open command to 3, 25, and then issuing an operation command to the BTB converter or the DC power transmission equipment 10, 11,
A state of DC interconnection as shown in FIG.

The system stabilization control device 12 continually takes in frequency information and the like of both systems and stabilizes the power by maintaining the power required to maintain the system frequency. As described above, in normal times, efficient system interconnection without loss of the converter is performed, and in the event of an accident, the configuration of DC interconnection can be easily changed only by turning on and off two circuit breakers.

As described above, according to this embodiment, all the AC interconnections can be promptly switched to DC interconnections in the event of an accident, and power can be interchanged to stabilize the system.

Embodiment 2 FIG. Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram showing a configuration of a power system stabilizing device according to another embodiment of the present invention. The corresponding parts are denoted by the same reference numerals as in FIG. 1 and description thereof is omitted.

In the normal state, the system is operated with the configuration shown in FIG. 2 as in the first embodiment, but an accident occurs in the power system B2, so that power interchange is required, and at the same time, power fluctuations occur in the power system B2. When this occurs, the system stabilization control device 12 issues a closing command to the circuit breakers 21 and 27 and issues an opening command to the circuit breakers 20 and 23 to make the configuration shown in FIG.

The BTB converter 11 controls transmission power so as to provide power interchange from the power system A1 to the power system B2.
The BTB converter 10 controls the passing electric power in the power system B2 in which the accident has occurred, thereby continuing the control in the direction in which the power fluctuation is contained. When the necessity of the power interchange and the power fluctuation disappear, the BTB converter stops the output and waits for the return to the AC interconnection.

With such a configuration, the power system A1 can contribute to stabilization without being affected by power fluctuations occurring in the power system B2, and only by supplying duty power. Give me

In this embodiment, the case where the power fluctuation occurs in the power system B2 has been described. However, even when the power fluctuation occurs in the power system A1, the closing command is supplied to the circuit breakers 24 and 27, , 25, a similar effect can be obtained.

As described above, according to the present embodiment, when power is insufficient in the system where the accident has occurred and large power fluctuations occur, one line is connected to a DC link to reduce the power fluctuations. At the same time as the power is sent, by controlling the passing power so as to calm the power fluctuation generated by using another DC power transmission equipment, it is possible to calm down without transmitting the fluctuation to the sound system side.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram showing a configuration of a power system stabilizer according to still another embodiment of the present invention.

Even if an accident occurs in the AC system and the respective systems input the system information 13 and 14 to the system stabilization control device 12, the power fluctuation is large and the fluctuation is suppressed while the two power systems are interconnected. In the case where it is difficult to perform the above operation, a closing command is issued to the circuit breakers 21 and 22 and an opening command is issued to the circuit breakers 20 and 23, and after being separated into two systems as shown in FIG.
By controlling the passing power so that the TB converters 10 and 11 suppress the system fluctuation, the respective power systems can be stabilized.

By adopting such a configuration, it is possible to easily change to a state in which the system is separated from the AC interconnection state and stabilize the system in each system, and to provide a configuration capable of coping with a serious accident. There is an effect that can be.

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram showing a configuration of a power system stabilizing device according to still another embodiment of the present invention, which is applied when the degree of an accident is minor.

Even if an accident occurs in the power system, it is a minor accident, and power fluctuations that are considered to have no problem even when the AC interconnection is maintained are required. 6, the circuit breaker 21 is turned on in a normal state, as shown in FIG. 6, and the BTB converter 10 is changed to a configuration that produces an effect of suppressing power fluctuation, thereby reducing the fluctuation. In this case, the AC interconnection is maintained, and if the power fluctuation stops, it is possible to return to the normal state by simply opening the circuit breaker 21.

As described above, even in the case of a minor accident, the power fluctuation can be suppressed without affecting the other party's AC system. In this case, the circuit breaker 27 in FIG. 6 may also be turned on, and the BTB converter 11 may also suppress power fluctuation.

Embodiment 5 Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a block diagram showing the configuration. In the first to fourth embodiments, the effects of the invention are realized by using two BTB converters or DC power transmission equipment and eight switches such as circuit breakers. However, as shown in FIG. However, it is possible to achieve the same effects as those of the first, second, and fourth embodiments, and it is possible to adopt a configuration that can cope with situations other than the third embodiment even if the capital investment is reduced, so that an extremely economical system A stabilizing device can be provided.

Embodiment 6 FIG. Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a block diagram showing a configuration of a power system stabilizing device according to still another embodiment of the present invention, in which 30, 31, 32, 33, 34, 3
Reference numerals 5, 36 and 37 denote switches such as circuit breakers.

Next, the operation will be described. In the figure,
In normal times, only the circuit breakers 30 and 37 are turned on to form an AC interconnection, and when an accident occurs in the system, the circuit breakers 30 and 37 constitute a parallel circuit as shown in FIG. 3
After turning on 1, 32, 35, and 36, the BTB converter or the DC power transmission equipment 10, 11 is started up, and the current flowing through the circuit breakers 30, 37 is replaced by a state where the current can be taken over.
An open command is sent to 0 and 37.

Thereafter, there is an effect that the two power systems can be separated and the system power stabilization control can be performed by adjusting the transmission power of the BTB converter.

When an accident occurs, only the circuit breakers 31 and 32 are turned on, and the circuit breakers 35 and 36 are kept open and the BTB
Only the converter 10 may be activated, then the circuit breakers 30 and 37 may be opened, and only the BTB converter 10 may be used to separate the power system and adjust the transmission power to perform the system stabilization control.

This embodiment can be applied to the first embodiment, and can also be applied to a seventh embodiment described later.

Embodiment 7 Next, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 10 is a block diagram showing the configuration, and the circuit configuration is the same as that of FIG. 9 of the sixth embodiment.

In normal times, the circuit breakers 30, 37 are turned on to connect the power systems A1 and B2, thereby realizing interconnection without BTB loss. For example, a system accident occurs in the AC system B2. Then, when it becomes necessary to perform power interchange from the electric power system A1 to the electric power system B2, the circuit breakers 31 and 32 are turned on, and the circuit breaker 30 is opened. Power can be exchanged.

Further, when the situation of the system accident is bad and further power interchange becomes necessary, as shown in FIG. 10, circuit breakers 33 and 34 are further turned on to further install another BTB converter or DC power transmission equipment. Is activated, power can be supplied to a total of two units.

By adopting such a configuration, it is possible to provide a configuration in which the magnitude of power interchange can be changed depending on the degree of a system fault. Note that, in the configuration of FIG. 10, the DC interconnection may be opened after the DC interconnection in the event of an accident as in the sixth embodiment.

Embodiment 8 FIG. Next, an eighth embodiment of the present invention will be described with reference to the drawings. FIG. 11 is a block diagram showing a configuration of a power system stabilizing device according to still another embodiment of the present invention. Reference numerals 41 and 42 denote synchronization verification devices.

When the two power systems are interconnected by a BTB converter or DC power transmission devices 10 and 11 due to a system fault, and the power system returns to a stable state as a result of performing the stabilization control, the two power systems are re-established. In order to return the system to the AC connection state, for example, it is necessary to turn on the circuit breakers 23 and 25. However, in the DC connection state, the two power systems operate independently, and It is not always the case that the phases of both sides of 25 are matched.

For this reason, the magnitude of the transmission power of the BTB converter or the DC power transmission devices 10 and 11 is adjusted and controlled in a direction such that the phases of the two systems coincide with each other.
2 can confirm the synchronization, issue a closing command to the circuit breakers 23 and 25, and then the BTB converter or the DC power transmission device 10,
If the circuit 11 is stopped and the circuit breakers 21 and 27 are opened, it is possible to return to the AC-connected state again.

As described above, in this embodiment, after the two power systems are separated and when the AC interconnection is performed again, the phases of the two systems are adjusted by controlling the power flow by the DC transmission equipment, and the circuit breaker is operated. , It is possible to easily return to AC interconnection.

Embodiment 9 FIG. Next, a ninth embodiment of the present invention will be described with reference to the drawings. FIG. 12 is a block diagram showing a configuration of a power system stabilizing device according to still another embodiment of the present invention.
C, 50, 51, 52, 53, 54 and 55 are interconnecting lines connecting the two power systems, and 61, 62, 63 and 64 are BTBs.
A converter or a DC power transmission device.

Now, a system accident occurs in the power system C3, and after the interconnection lines 52, 53, 54, 55 are changed to have a BTB converter or an interconnection configuration by DC transmission, each BTB conversion is performed. When the power supply or the DC power transmission equipment controls the transmission power based on its own judgment, the power fluctuations that occur are not calmed down, but rather work to expand.

In order to prevent such a situation, a role to be played by a BTB converter or a DC power transmission facility installed at each interconnection point is specified in advance, and system control can be performed without interfering with each other. Be able to achieve your goals. Of course, it is needless to say that the same effects can be obtained as long as these roles are not limited to fixed ones and can be uniquely determined based on system conditions.

For example, the BTB converters 61 and 62 may be dedicated to power supply (interchange), and the fluctuation of the system may be shared by the BTB converters 63 and 64. Alternatively, a BTB converter close to the fault point may be in charge of a system oscillation function, and a BTB converter far from the fault point may be in charge of only power supply.

As described above, in the present embodiment, when three or more AC systems are interconnected, unnecessary control is generated at each interconnection point, thereby causing unnecessary oscillations in the system and stabilizing the system. Since there is a risk that the system will not be able to be achieved, assign a function to be assigned to each interconnection point, and set a location that is dedicated to power supply through power interchange and a location that is dedicated to calming power fluctuations, and achieve a smooth target. System stabilization control can be performed.

[0058]

As described above, according to the present invention, an AC interconnection having a small transmission loss during normal times is provided, and in the event of a system failure, DC interconnection using a DC transmission facility and system fluctuation suppression are easily performed. Is performed, it is possible to perform control in accordance with the purpose of power interchange and fluctuation suppression, and there is an effect that a system stabilization control that does not impose too much load on a healthy system can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a system stabilization device according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration in a normal state according to the first embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration when an accident occurs according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a system stabilizing device according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a system stabilizer according to Embodiment 3 of the present invention.

FIG. 6 is a block diagram of a system stabilizing device according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram of a system stabilizing device according to a fifth embodiment of the present invention.

FIG. 8 is a block diagram of a system stabilization device according to a sixth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration when an accident occurs according to a sixth embodiment of the present invention.

FIG. 10 is a block diagram of a system stabilizing device according to a seventh embodiment of the present invention.

FIG. 11 is a block diagram of a system stabilizing device according to an eighth embodiment of the present invention.

FIG. 12 is a block diagram of a system stabilization device according to Embodiment 9 of the present invention.

FIG. 13 is a block diagram showing a conventional system stabilization device.

[Explanation of symbols]

1, 2 Power system 10, 11 BTB converter or DC power transmission device 12 System stabilization control device 13, 14 System information 15 Control signal 20, 21, 22, 23, 24, 25, 26, 27 Circuit breaker 30, 31, 32, 33, 34, 35, 36, 37 Circuit breaker 41, 42 Synchronization verification device 50, 51, 52, 53, 54, 55 Interconnection line 61, 62, 63, 64 BTB converter or DC power transmission equipment 101, 201 First connection point, 102, 202 Second connection point

Claims (14)

[Claims] 1. An AC system is normally connected to an AC system that can perform AC interconnection and a DC interconnection with a DC power transmission facility to adjacent AC systems, and the AC system is separated in the event of an AC system accident. A method for stabilizing an electric power system, wherein the method includes a direct-current (DC) interconnection to perform at least one of transmission and reception of power and suppression of system fluctuation. 2. An AC system is normally connected to an AC system that can perform AC interconnection to an adjacent AC system and DC interconnection with a plurality of DC transmission facilities, and in the event of an AC system accident,
Separate the AC system, use at least one of the above-mentioned DC transmission facilities for DC interconnection, and use at least one of the other DC transmission facilities to suppress system fluctuations in the accident system. A power system stabilization method characterized by the following. 3. An AC system is normally connected to an AC system that can perform AC interconnection to an adjacent AC system and DC interconnection with a plurality of DC transmission facilities, and in the event of an AC system accident,
A method for stabilizing a power system, comprising separating an AC system and suppressing system fluctuations in each system by using at least one of the DC power transmission facilities for each AC system. 4. An AC system is normally connected to an AC system capable of performing AC interconnection to a mutually adjacent AC system and a DC system using DC transmission equipment, and in the event of an AC system accident, the AC system is interconnected. A method for stabilizing an electric power system, wherein system fluctuations in an accident system are suppressed by using the DC power transmission equipment as it is. 5. An AC system is normally connected to an AC system that can perform AC interconnection to a mutually adjacent AC system and DC interconnection with a DC transmission facility, and is connected to the DC system in the event of an AC system failure. A method for stabilizing a power system, comprising: separating an AC system, and then separating the AC system or suppressing system fluctuation using the DC power transmission equipment connected to the DC system. 6. A power system that can perform AC interconnection to an adjacent AC system and DC interconnection by a plurality of DC power transmission facilities, and in normal times, performs AC interconnection, and in the event of an AC system accident,
A method for stabilizing a power system, wherein an AC system is separated, and DC connection is performed using one or a plurality of DC power transmission facilities according to power exchanged between the AC systems. 7. The method for stabilizing a power system according to claim 1, wherein when the separated AC system is again connected to an AC system, the separated DC system is connected to the DC system using a DC power transmission facility. A power flow stabilizing method, wherein the phases of both power systems are matched by power flow control to shift to AC interconnection. 8. A power system having two connection points, a first connection point and a second connection point, each of which is constituted by an AC system A and an AC system B adjacent to each other. A series body of DC power transmission equipment and switching means is connected between the first connection point and the second connection point of the AC systems, and the DC connection between the first connection point of the AC system A and the second connection point side. Switching means is connected between the AC system B side terminal of the equipment, and the switching means is connected between the second connection point of the AC system A and the AC system B terminal of the first connection point side DC transmission equipment. A switching means is connected between the first connection point of the AC system B and the AC system A terminal of the DC power transmission equipment on the second connection point side;
By configuring a circuit in which switching means is connected between the connection point and the AC system A terminal of the first connection point side DC power transmission equipment, by controlling the opening and closing of the switching means and the operation of the DC power transmission equipment. A power system stabilizing device including control means for performing AC interconnection, DC interconnection, and system fluctuation suppression. 9. The power system stabilizing device according to claim 8, wherein the control means is means for performing the power system stabilizing method according to at least one of claims 1 to 4. 10. Each of a first connection point and a second connection point
Power system having two connection points and comprising an AC system A and an AC system B adjacent to each other, wherein a series body of switching means, DC transmission equipment and switching means is connected to a first connection point of the two AC systems. Connecting between the first connection point of the AC system B and the AC system A terminal of the second connection point side DC power transmission equipment, and connecting between the first connection point of the AC system B and the second connection point. A circuit in which switching means is connected between the second connection point of B and the AC system A side terminal of the first connection point side DC power transmission equipment is configured, and the switching of the switching means and the operation of the DC power transmission equipment are performed. By controlling, AC interconnection, DC interconnection,
An electric power system stabilizing device including control means for suppressing system fluctuation. 11. A power system stabilizing device according to claim 10, wherein the control means is means for performing the power system stabilizing method according to at least one of claims 1, 2, and 4. 12. Each of a first connection point and a second connection point
A power system having two connection points and constituted by an AC system A and an AC system B adjacent to each other, wherein a series body of switching means, DC transmission equipment, and switching means, and a switching apparatus connected in parallel to the series body Means connected to each of a first connection point and a second connection point between the two AC systems, and connected to an AC system A-side terminal of the first connection point side DC power transmission equipment and the second connection point.
Opening / closing means is connected between an AC system A terminal of the connection point side DC power transmission equipment, and an AC system B side terminal of the first connection point side DC power transmission equipment and an AC system of the second connection point side DC power transmission equipment. A circuit for connecting an open / close means to the B-side terminal and controlling the open / close of the open / close means and the operation of the DC power transmission equipment to control AC interconnection, DC interconnection, and system fluctuation suppression. An electric power system stabilizing device provided with means. 13. The power system stabilizing apparatus according to claim 12, wherein the control means is means for performing the power system stabilizing method according to at least one of claim 5 and claim 6. 14. A power system in which AC interconnection and DC interconnection by DC power transmission equipment can be performed between three or more AC systems in a normal state, and in the event of an AC system failure, a desired AC system is provided. A method for stabilizing a power system, wherein the system is stabilized by performing at least one of power interchange and system fluctuation suppression by DC interconnection using the DC power transmission equipment.