JP3402886B2 - Distributed power equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed power supply system in which a distributed power supply such as a power storage system is connected to a power system to operate and supply power to a load. In particular, the present invention relates to a distributed power supply system capable of surely supplying power to a load without interruption even when an abnormality occurs in a power system while improving the efficiency of the equipment and reducing the size of the equipment. 2. Description of the Related Art Recently, much research and development has been conducted on power supply equipment such as a distributed power storage system. Regarding the connection of these decentralized power supply facilities to the power grid, guidelines on grid interconnection were established,
It is considered that the technology will be established and will be installed together with general power receiving equipment such as buildings in the future. [0003] Further, it has been studied to add an uninterruptible power supply (UPS) function to such a distributed power supply and use it as a power supply for disaster prevention. In this way, when a distributed power supply system is installed in a building or the like and connected to the power system for operation, ensuring stability, coordinating protection with the power system, and the ability to continue supplying power to the load even during an instantaneous voltage drop, etc. Is required. Hereinafter, an example of a general distributed power storage system will be described with reference to FIG. In FIG.
The interconnection reactor 2, the power conversion device 3, and the storage battery 4 are connected to the power system 0 via the interconnection breaker 1. In addition, a load 5 is connected to the power system 0, and a connection protection device 6 is provided between the power system 0 and the connection breaker 1.
Is installed. Here, the power converter 3 is of a self-excited type,
At night, the electric power is stored in the storage battery 4, and at the peak load in the daytime, the operation of discharging the electric power stored in the storage battery 4 to the AC side is performed. [0006] When the power system 0 is out of power, the power conversion device 3 temporarily stops, and after confirming that the power system 0 is surely disconnected from the power system 0, switches the operation control mode from current control to voltage control. Independent operation is performed to supply power to the load 5. On the other hand, as shown in FIG.
When a PS (PS) device is used, power is supplied to the load 5 via the second power converter 3-2 while charging the storage battery 4 with the first power converter 3-1 in normal times. When a power failure occurs in the power system 0, the storage battery 4
Is supplied to the load 5 via the second power converter 3-2. However, the above-mentioned distributed power supply equipment has the following problems. That is, first, in the case of the power storage system, when the voltage, frequency, and the like of the power system 0 are abnormal, the operation of the power converter 3 is temporarily stopped. Can not continue to supply power. In addition, the external dimensions of the interconnection reactor 2 for suppressing voltage fluctuation when the power system 0 is disconnected become large. On the other hand, if this system is to be realized by an uninterruptible power supply (UPS) device, power can be continuously supplied to the load 5 even when the power system 0 is disconnected, but two power converters are required. Therefore, there is a problem that the cost increases and the operation efficiency decreases. [0011] As described above, in the conventional distributed power supply equipment, power cannot be continuously supplied to the load when the power system is abnormal, the equipment becomes large, and the operation efficiency increases. Was low. SUMMARY OF THE INVENTION It is an object of the present invention to provide a distributed power supply system capable of reliably supplying power to a load without interruption even when a power system is abnormal, while improving the efficiency of the equipment and reducing the size of the equipment. Is to provide. [0013] In order to achieve the above-mentioned object, the present invention provides a power supply system such as a power storage system.
Connected to the power system to operate and supply power to the load
If the operation control mode is
Has a high-speed switching control function that switches instantaneously to voltage control from
A power conversion device for performing AC / DC power conversion;
The power conversion device is provided so that it can be separated from the grid.
Disconnected means, between the power system and the power converter
Provided to detect abnormalities such as voltage and frequency of the power system
System abnormality detecting means, and the system abnormality detecting means
When a power system abnormality is detected, the power system
Disconnect the power converter and operate the power converter.
Switch the current control mode from current control to voltage control,
1st control to shift from grid-connected operation to independent operation
Control means and switching frequency during grid-connected operation
Low, and the switching frequency increases during autonomous operation.
Control the control system of the power converter and
The voltage waveform of the power system immediately before the power system is disconnected and
The output voltage waveform of the power converter after disconnection from the power system
A second control means connected in 1/4 cycle or less.
It is characterized by having done. According to the present invention, first, the first control means
Power system abnormality detected by the system abnormality detection means
The power converter from the power grid
And the operation control mode of the power converter
Switching from control to voltage control, independent from grid-connected operation
By controlling to shift to operation, power system abnormalities
Power supply to the load without interruption.
Can be. In addition, the grid connection operation is performed by the second control means.
During operation, the switching frequency is lowered for high efficiency operation.
On the other hand, when operating independently, increase the switching frequency.
Improves the transient response of the power converter and provides stable power to the load
Can be supplied, especially when the power system is disconnected
The voltage waveform of the power system immediately before
The output voltage waveform of the power converter is reduced to 1/4 cycle or less.
By connecting, it is possible to switch from detection of power system abnormality to independent operation.
Set a series of control speeds up to switching to 1/4 cycle or less.
In this way, the voltage of the load system can be
Detection of power system abnormality so that it does not fall below a certain value
The control speed from switching to autonomous operation
Less than one cycle, only one power converter
And a configuration in which the interconnection reactor is omitted.
Therefore, the device can be made compact. The following is a description of embodiments of the present invention. An embodiment of the present invention will be described in detail with reference to the drawings. (First Embodiment) FIG. 1 is a circuit diagram showing a configuration example of a distributed power supply equipment according to the present embodiment. In FIG. 1, a power conversion device 12 and a storage battery 13 are connected to a power system 10 via a connection breaker 11 which is a disconnecting means. Further, a load 14 is connected to the power system 10, and a connection protection device 15 is provided between the power system 10 and the connection breaker 11. Here, the interconnection breaker 11 is constituted by a high-speed switching element such as an IGBT switch that can be opened at a high speed, and enables the power converter 12 to be separated from the power system 10. The power converter 12 is of a self-excited type,
It has a high-speed switching control function for instantaneously switching the operation control mode from current control to voltage control, and performs AC / DC power conversion (power is stored in the storage battery 13 at night, and stored in the storage battery 13 during daytime load peaks. Operation to discharge the discharged power to the AC side). This power converter 12
Except when the system is abnormal, the system interconnection operation is performed, and the independent operation is performed only when the system is abnormal. Further, the interconnection protection device 15 is connected to the power system 1.
It has a system abnormality detection function (high-speed power failure detection function) for detecting an abnormality such as a voltage or frequency of 0. Next, the operation of the distributed power supply equipment of the present embodiment configured as described above will be described. First, the interconnection protection device 15 detects whether there is any abnormality in the power system 10 such as voltage and frequency. As a result of this detection, if the power system 10 side is normal, the power converter 12 performs the system interconnection operation, and repeatedly performs the charging / discharging operation corresponding to day and night time zones. In the case where the power system 10 is out of power, the interconnection breaker 11 is cut off at a high speed, the operation control mode of the power converter 12 is switched from current control to voltage control, and discharge operation (independent operation) is performed. Operation) and load 14
Power supply without interruption. Next, when the power system 10 recovers in such a state, the power system 10 is synchronized with the power system 10 and the connection breaker 11 is turned on. The operation is switched from control to current control. At this time, the AC output of the power converter 12
Between the power system 10 and the power system 10, even when the system voltage is lost, such that the instantaneous decrease of the voltage with respect to the load 14 does not exceed a predetermined constant rate or a predetermined time.
In addition, an interconnection reactor with a minimum capacity is used. By repeatedly performing the above-described operation control, even in the event of a power outage on the power system 10 side, the load 14 equipment in the station is provided with an instantaneous voltage that affects the operation of the load 14. Without any significant decline
Power can be supplied continuously. As described above, the distributed power supply system of this embodiment has the high-speed switching control function of instantaneously switching the operation control mode from the current control to the voltage control, and performs the power conversion device 12 for performing the AC / DC power conversion. And an interconnection breaker 11, which is a disconnecting means provided so as to be able to disconnect the power converter 12 from the power system 10, and is constituted by a high-speed switching element such as an IGBT switch, and the power system 10 and the power converter. And an interconnection protection device 15 having a system abnormality detection function for detecting an abnormality in the power system 10 such as a voltage and a frequency.
When a 0 abnormality is detected, the power conversion device 12 is disconnected from the power system 10, and the operation control mode of the power conversion device 12 is instantaneously switched from current control to voltage control to shift from grid-connected operation to independent operation. It is like that. Accordingly, the power converter 12 is provided with a UPS function, and only one power converter 12 is provided. When the power system is abnormal, the power converter 12 is instantaneously disconnected from the power system 10 and the operation mode is changed to the independent operation mode. Since the operation can be switched, the power can be reliably supplied to the load 14 without interruption even when the power system 10 is abnormal. Further, since the interconnection breaker 11 is constituted by a high-speed switching element such as an IGBT switch, the power system 10 and the power converter 12
Can be separated at a higher speed. (Second Embodiment) FIG. 2 is a circuit diagram showing a configuration example of the distributed power supply equipment according to the present embodiment.
The same elements as those described above are denoted by the same reference numerals and description thereof will be omitted, and only different parts will be described here. That is, in the distributed power supply equipment of this embodiment, as shown in FIG. 2, the interconnection breaker 11 is composed of a thyristor switch 11-2, which is a switching element having a large inrush withstand capacity, and a high-speed switching element. This is a hybrid configuration combining the IGBT switch 11-1. That is, in the distributed power supply system according to the first embodiment, the interconnection breaker 11 is constituted by a high-speed switching element such as an IGBT, so that when the power system 10 is abnormal, the power system 10 Although the device 12 is disconnected at high speed, in the case of large-capacity power supply equipment, there is a possibility that the switching element of the interconnection breaker 11 may be damaged due to inrush current at the time of starting the power supply equipment or an accident in the power system 10. Occurs. In this regard, in the case of the distributed power supply equipment of the present embodiment, the configuration in which the thyristor switch 11-2 which is a switching element having a large rush tolerance and the IGBT switch 11-1 which is a high-speed switching element are combined. By doing so, it is possible to disconnect from the power system 10 at high speed, as in the case of the first embodiment described above. In the operation of the interconnecting circuit breaker having such a configuration, the thyristor switch 11-2 is turned on at the time of starting, then the thyristor switch 11-2 is turned off and the IGBT switch 11-1 is turned on. If the inrush current exceeds a certain value during operation, the IGBT switch 11-1 is turned off,
The thyristor switch 11-2 is turned on. Then, when the inrush current is reduced, the thyristor switch 1
1-2 is turned off and the IGBT switch 11-1 is turned on. As described above, in the distributed power supply system according to the present embodiment, the thyristor switch 11-2, which is a switching element having a large withstand voltage, and the IGBT switch 11-1, which is a high-speed switching element, are connected to the interconnection breaker. It is designed to be combined to form a hybrid configuration. Therefore, it is possible to obtain the same effect as that of the first embodiment, and in addition to this,
In the case of large-capacity power supply equipment, it is possible to prevent problems such as damage to switching elements of interconnected circuit breakers due to inrush current when the power supply equipment is started or when a power system accident occurs. It is possible to improve the performance. (Third Embodiment) FIG. 3 is a circuit diagram showing a configuration example of a distributed power supply system according to the present embodiment.
The same elements as those described above are denoted by the same reference numerals and description thereof will be omitted, and only different parts will be described here. That is, as shown in FIG. 3, the distributed power supply equipment of the present embodiment has a configuration in which a first control device 16 having a function of preventing the power conversion device 12 from operating independently is added. It is. Therefore, the distributed power supply system of the present embodiment is provided with the first control device 16 having the function of preventing the power conversion device 12 from operating independently. It goes without saying that the same effect can be obtained, and in addition to this, the reliability of the power failure detection is increased, and it is possible to switch from the grid-connected operation to the independent operation more safely and at a higher speed. (Fourth Embodiment) FIG. 4 is a circuit diagram showing a configuration example of a distributed power supply system according to the present embodiment.
The same elements as those described above are denoted by the same reference numerals and description thereof will be omitted, and only different parts will be described here. That is, as shown in FIG. 4, the distributed power supply system of this embodiment has a function of making the feedback control speed of the control system of the power converter 12 variable between the system interconnection operation and the self-sustaining operation. Is added to the second control device 17 having. Therefore, in the distributed power supply system of the present embodiment, the second control device having the function of making the feedback control speed of the control system of the power conversion device 12 variable between the system interconnection operation and the self-sustaining operation. 17 to provide the same effects as those of the third embodiment described above, and in addition to this, the switching frequency is reduced during grid interconnection operation to achieve high efficiency operation. Conversely, during the self-sustaining operation, the switching frequency is increased to improve the transient response of the power conversion device 12, and it is possible to stably supply power to the load 14. In particular, in this case, when the power system 10 is abnormal, the voltage of the load system does not drop below a certain value.
By reducing a series of control speeds from detection of an abnormality in the power system 10 to switching of the independent operation to 1/4 cycle or less,
Since the configuration can be such that the interconnection reactor is omitted, the device can be made compact. As a result, the operating efficiency and the reliability of power supply to the load 14 can be improved. As described above, according to the present invention, the power storage
Operation by connecting a distributed power source such as a storage system to the power grid.
In distributed power facilities that supply power to
Instantly switch the operation control mode from current control to voltage control.
It has a high-speed switching control function to perform AC / DC power conversion.
And a power converter for the power system.
Disconnecting means provided so that the switching device can be separated;
A power system provided between the power system and the power converter;
System abnormality detection means for detecting abnormalities in voltage, frequency, etc.
And a power system abnormality is detected by the system abnormality detection means.
Disconnects the power converter from the power system
In addition, the operation control mode of the power
Control to voltage control to switch from grid-connected operation to independent operation.
First control means for performing control to shift to
During system operation, the switching frequency is low.
The power conversion so as to increase the switching frequency.
The control system of the device is controlled and the power system is disconnected.
Voltage waveform immediately before the power system
The output voltage waveform of the power converter is reduced to 1/4 cycle or less.
By providing the second control means for connection,
Control means, and the power system
When a power failure is detected, the power system
Disconnecting the power conversion device and controlling the operation of the power conversion device.
Switch the mode from current control to voltage control, and
By controlling to shift from operation to autonomous operation,
Even if the power system is abnormal, the power is
Can be supplied. Also, the second control means
Therefore, lower the switching frequency during grid-connected operation.
High efficiency operation is possible.
By increasing the wave number to improve the transient response of the power converter,
It can supply stable power to loads, especially in power systems.
The voltage waveform of the power system immediately before the
The output voltage waveform of the power converter after disconnection is reduced to 1/4
By connecting in less than the cycle, detection of power system abnormality
1/4 of the series of control speeds from switching to autonomous operation
With less cycle, when the power system abnormality,
To prevent the load system voltage from dropping below a certain value,
A series of controls from detection of a system abnormality to switching to independent operation
Power conversion by reducing the speed to 1/4 cycle or less
There is only one device, and the interconnection reactor is omitted.
Equipment can be made compact,
You. As described above, the load can be increased even when the power system is abnormal, while improving the efficiency of the equipment and reducing the size of the equipment. And a decentralized power supply equipment capable of reliably supplying power without interruption.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing a first embodiment of a distributed power supply system according to the present invention. FIG. 2 is a circuit diagram showing a second embodiment of the distributed power supply equipment according to the present invention. FIG. 3 is a circuit diagram showing a third embodiment of the distributed power supply equipment according to the present invention. FIG. 4 is a circuit diagram showing a fourth embodiment of the distributed power supply equipment according to the present invention. FIG. 5 is a circuit diagram showing a configuration example of a conventional power storage system. FIG. 6 is a circuit diagram showing a configuration example of a conventional uninterruptible power supply. [Description of Signs] 0: power system, 1: interconnected circuit breaker, 2: interconnected reactor, 3: power converter, 3-1: power converter, 3-2: power converter, 4: storage battery, 5 ... Load, 10 ... Power system, 11 ... Interconnection breaker, 11-1 ... IGBT switch, 11-2 ... Thyristor switch, 12 ... Power conversion device, 13 ... Storage battery, 14 ... Load, 15 ... Interconnection protection device, 16: first control device (independent operation prevention function); 17: second control device (control speed variable function).

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hirofumi Shinohara 1-1-1, Shibaura, Minato-ku, Tokyo Inside the Toshiba head office (72) Inventor Eiichi Igawa 1-Toshiba-cho, Fuchu-shi, Tokyo Toshiba Fuchu Plant (72) Inventor Katsuhisa Inagaki 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation Fuchu Plant (72) Masato Hatakeyama 1-1-1, Shibaura, Minato-ku, Tokyo Toshiba Corporation In the office (56) References JP-A-7-336898 (JP, A) JP-A-7-39086 (JP, A) JP-A-7-177748 (JP, A) JP-A-7-321215 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02J 9/00-11/00 H02J 3/38 H02J 7/34 H02M 7/48

Claims (1)

(57) [Claims 1] In a distributed power supply system in which a distributed power supply such as a power storage system is connected to a power system to operate and supply power to a load, an operation control mode is set to a current A power conversion device that has a high-speed switching control function of instantaneously switching from control to voltage control and performs AC / DC power conversion; and disconnection means that is provided so that the power conversion device can be separated from the power system. A system abnormality detecting means provided between the power system and the power conversion device for detecting an abnormality of the power system, such as a voltage and a frequency, and a power system abnormality detected by the system abnormality detecting means.
In this case, disconnecting the power converter from the power system
In both cases, whether the operation control mode of the power converter is current control
Switch to voltage control from grid-connected operation to independent operation.
A first control means for controlling so as to shift, at the time of system-interconnected run low switching frequency, self luck
In order to increase the switching frequency during rotation,
Controls the control system of the power converter and disconnects the power system.
Power system voltage waveform just before separation and power system disconnection
1/4 cycle with the output voltage waveform of the power converter
A distributed power supply system comprising: a second control unit connected as follows .