JP2000253584A - Distributed power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distributed power supply system, wherein a plurality of distributed power supply units can be operated in parallel without damages to a commercial power supply or distributed power supplies. SOLUTION: A distributed power supply system is provided with distributed power supply units, which performs system linkage between the direct-current power supplies 8 and a commercial power supply 1 and a display 15, which is connected with a plurality of the distributed power supply units and controls the operation of the distributed power supply units. The distributed power supply system is so designed that the display 15 gives permission to generate power to the distributed power supplies 7, only when all the distributed power supplies recognize the power supply from the commercial power supply 1 to be normal, and when all the distributed power supplies 7 recognize the power supply from the commercial power supply 1 to be abnormal, the distributed power supplies 7 generate power only when such a permission to generate power is given.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply using a DC power supply such as a solar cell, which is electrically connected to a commercial power supply.
The present invention relates to a distributed power supply system that performs a system interconnection operation so as to supply power to a common load.

[0002]

2. Description of the Related Art FIG. 5 is a schematic block diagram of a conventional distributed power supply (solar power generation apparatus) using a solar cell as a DC power supply. In FIG. 5, reference numeral 1 denotes a power system of a commercial power supply,
A main power source 2 of the power plant, a power plant 3 that steps down the power from the power plant 2 and distributes the power, a circuit breaker 5 provided on the distribution line 4,
A pole transformer 6 for reducing the supplied electric power and supplying it to each home. Reference numeral 8 denotes a solar cell installed in each home. The distributed power source 7 includes a grid-connected power converter 10 that converts a DC voltage output from the solar cell 8 into an AC voltage.

[0003] Reference numeral 12 denotes a system interconnection protection circuit, which operates the disconnecting switch 11 when the state of the commercial power supply 1 is normal to interconnect the distributed power supply 7 with the commercial power supply 1. When an abnormality or a power failure of the commercial power supply 1 is detected, the power converter 9 stops supplying power to the commercial power supply 1, disconnects the disconnecting switch 11, and disconnects the distributed power supply 7.
When the abnormality and the power failure of the commercial power supply 1 are no longer detected, the disconnecting switch 11 is operated again to interconnect the distributed power supply 7 and the commercial power supply 1 with the system.

When the system interconnection protection circuit 12 recognizes that the commercial power supply 1 is normal and performs system interconnection, power is supplied from the commercial power supply 1 to the shared branch circuit 16 and the interconnection protection circuit 12 When it is determined that 1 is abnormal / power failure, power is supplied from the power converter 9.

In the distributed power supply device having the above-described configuration,
When DC power is output from the solar cell 8, the power is converted into AC power of a predetermined frequency by the power converter 9 and the AC power is supplied to the load in the house, while the power that cannot be covered by the AC power from the distributed power source Is supplied from the commercial power supply 1.

In the basic configuration of the distributed power supply device shown in FIG. 5, reference numeral 8 denotes a solar cell, and reference numeral 10 denotes a grid-connected power converter. This grid-connected power converter 10 includes the above-described power converter 9, a parallel-off switch 11, and a grid-connected protection circuit 12. In addition, the grid-connected power converter 10 has a display 15 connected by a cable 14. The display 15 displays the solar cells 8 of the distributed power source 7 so that the user can easily grasp the power generation state of the distributed power source.
, The power generation amount, the integrated power amount, the state of the commercial power supply 1, and the state of the grid-connected power converter 10.

[0007]

In the case of a distributed power supply system (see FIG. 6) in which a plurality of distributed power supplies having the above-described configuration are connected to the commercial power supply 1 in parallel and operated (see FIG. 6), each distributed power supply 7 Each is operated independently. Therefore,
Even if the system interconnection protection device 12 of a certain distributed power source 7 erroneously detects an abnormality and a power failure of the commercial power source 1 and separates the systems, the other distributed power sources 7 ′ continue to be connected to the solar cells 8 ′. Is supplied to the power converter 9 ′, the power converter 9 ′ converts DC into AC and continuously supplies power to the commercial power supply 1.

[0008] In such a case, when DC power of a predetermined value or more is supplied to the solar cell 8 in the distributed power source 7 separated from the system, power is supplied from the power converter 9 to the shared branch circuit 16. become. However, since the actual state of the commercial power supply 1 is normal, power is also supplied from the commercial power supply 1. At this time, the contacts of the shared branch circuit 16 are charged by two types of AC outputs, but the phases of the two are not generally coincident with each other. Therefore, there is a problem that an excessive current flows and the commercial power source 1 and the distributed power source 7 may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a distributed power supply system capable of operating a plurality of distributed power supply devices in parallel without damaging a commercial power supply or a distributed power supply. A power supply system is provided.

[0010]

According to the first aspect of the present invention,
A DC power supply, a power converter for converting DC output from the DC power supply to AC, and, when an abnormality / power failure of the commercial power supply is detected, stopping the power supply output from the power converter to the commercial power supply and performing system separation, When the abnormality of the commercial power supply / release of the power failure is detected, the distributed power supply having a grid connection protection device that performs grid connection and restarts the power supply from the power converter to the commercial power supply, and the power from the commercial power supply during grid connection. A distributed power supply device including a shared branch circuit that is supplied with power from the power converter at the time of system separation and a plurality of distributed power supply devices are connected, and an indicator that controls operation of each distributed power supply device;
In a distributed power supply system with a power supply, the display is only displayed when all the distributed power supplies recognize the power supply of the commercial power supply as normal and when all the distributed power supplies recognize the power supply of the commercial power supply as abnormal. The power generation is given permission to the distributed power source, and the distributed power source generates power only when the power generation permission is given.

According to a second aspect of the present invention, in the distributed power supply system according to the first aspect, the display unit gives permission for power generation to all the distributed power supplies when any of the distributed power supplies has an abnormality. The feature is that it is not provided.

According to a third aspect of the present invention, in the distributed power supply system according to the first or second aspect, when the display has an abnormality in communication between any one of the distributed power supplies and the display, all of the display units are connected. It is characterized in that the power generation is not given permission to the distributed power source.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a distributed power supply system according to an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a schematic configuration diagram of a distributed power supply system. FIG. 2 is a flowchart showing the operation of the distributed power supply system. FIG. 3 is a flowchart showing an operation of the distributed power supply system according to another embodiment. FIG. 4 is a flowchart showing an operation of the distributed power supply system according to another embodiment. Note that the same parts as those of the distributed power supply device and the distributed power supply system shown in the section of the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

The distributed power source 7 is constituted by a solar cell 8 corresponding to a DC power source and a system interconnection type power converter 10.
The distributed power supply system 18 includes a plurality of distributed power supplies 7 and the display 15. The grid-connected power converter 10 includes a power converter 9, a parallel-off switch 11, a grid-connected protection device 12, a transmission / reception circuit 19, and a sensor unit 17. The display 15 is provided with a transmitting / receiving circuit 15a
, Operation control circuit 15b, display unit 15c, operation unit 1
5d.

The power converter 9 converts DC power input from the solar cell 8 as a DC power supply into AC, and outputs AC power to the commercial power supply 1 when the power system is interconnected, and to the shared branch circuit 16 when the power system is separated. Things. The disconnection switch 11 is a switch for connecting and disconnecting the distributed power supply 7 and the commercial power supply 1, and is controlled by the system interconnection protection device 12.

The system interconnection protection device 12 outputs a control signal for controlling the power converter 9 when signals from the voltage sensor and the current sensor provided in the sensor section 17 are input. Further, the system interconnection protection device 12 detects a frequency abnormality or a voltage abnormality in the system of the distributed power supply 7 or a power failure of the commercial power supply 1 based on a voltage signal or a current signal from the sensor unit 17, and disconnects based on the abnormality. By controlling the switch 11, the distributed power supply 7 is disconnected from the commercial power supply 1, the AC output to the commercial power supply 1 is stopped by the power converter 9, and when the system separation is confirmed, the shared branch circuit 16 is connected to the power converter 9. To restart output. When it is detected that the abnormality and the power failure of the commercial power supply 1 have been eliminated, the power converter 9 stops the output of the AC power to the shared branch circuit 16 and controls the parallel-off switch 11 to reconnect the distributed power supply 7 to the system. The power converter 9 restarts the AC current output to the commercial power supply 1 when the system interconnection is confirmed.

Further, the interconnection protection device 12 notifies the display 15 of the operation state of the distributed power source 7 such as the state of the solar cell voltage and the system voltage, the operation state of the power converter 9, and the presence or absence of an abnormality. As means for that purpose, the grid-connected power converter 10
Is a transmission / reception circuit 19, and the display 15 is a transmission / reception circuit 15a.
Is provided. The transmission and reception circuits 19 and 15a may be wired communication or wireless communication.

The display 15 performs an operation based on the transmission / reception circuit 15a and the notified operating state of each distributed power supply 7, determines a command for controlling the operation of the distributed power supply system 18, and displays a display 15c. An operation control circuit 15b for determining the content to be displayed on the display, a display unit 15c for displaying the display content determined by the operation control circuit 15b, and an operation device 15d for receiving a user's request such as start or stop of operation. Is provided.

Next, the operation of the distributed power supply system 18 according to the present embodiment will be described with reference to FIG. In addition,
Here, a distributed power supply system 18 including two distributed power supplies 7 and 7 'will be described, but the number of distributed power supplies 7 is not limited to this.

The distributed power sources 7, 7 'are connected to sensor units 17, 17'.
The state of the commercial power supply 1 is constantly monitored based on the voltage and current signals from the CPU, and the obtained state of the commercial power supply 1 is notified to the display 15 using the transmission / reception circuits 19 and 19 '(see S21). The display 15 transmits the notified data to the transmission / reception circuit 15.
a, and the operation control circuit 15b monitors whether each of the distributed power sources 7, 7 'recognizes the state of the commercial power supply 1 as normal, abnormal, or power failure (S
11).

The operation control circuit 15b permits the system interconnection generation when both the distributed power source 7 and the distributed power source 7 'recognize the commercial power source 1 as normal (see S13), and the distributed power source 7 and the distributed source 7 'Both recognizes that the commercial power supply 1 is abnormal or blackout, and permits system-separated power generation (see S15). A permission signal is sent to the distributed power supplies 7 and 7' via the transmission / reception circuit 15a. You will be notified. The operation control circuit 15b also determines that the distributed power source 7 recognizes that the commercial power source 1 is normal and the distributed power source 7 ′ determines that the commercial power source 1 is abnormal or power outage.
In 7 ', when there is a difference in recognition regarding the state of the commercial power supply 1, no notification is made to the distributed power supplies 7, 7'. On the other hand, the distributed power sources 7 and 7 'start the system interconnection power generation only when the system interconnection generation permission is received (S3).
0), the system-separated power generation is started only when the system-separated power generation is permitted (see S28).

In the above-mentioned distributed power supply system 18, among the distributed power supplies 7 and 7 'interconnected with the system, the distributed power supply 7' erroneously detects an abnormality or power failure of the commercial power supply 1 and separates the system. Even if the power supply is performed, since the recognition of the state of the commercial power supply 1 is different from each other, the permission of the system-separated power generation is not notified from the display 15. 'Does not start system-separated power generation (see S26). That is,
Grid-connected power generation and grid-separated power generation do not occur simultaneously. Therefore, a dangerous state in which two types of AC voltages are output to the contacts of the shared branch circuit 16 'does not occur, and it is possible to eliminate the risk of damaging the commercial power supply 1 and the distributed power supply 7'. It becomes.

Further, as information to be notified from the distributed power source 7 to the display 15, the presence or absence of abnormality of each of the distributed power sources 7 and 7 ′ is added (see S 11 ′ and S 21 ′ in FIG. 3) and the display 1 is displayed.
Reference numeral 5 may be such that when an abnormality has occurred in any of the distributed power sources 7 and 7 ', the system interconnection power generation and the system separation power generation are not permitted (see S16 in FIG. 3). This allows
Even if all of the distributed power sources 7 and 7 ′ recognize the commercial power source 1 as being in the same state, if any of the distributed power sources 7 and 7 ′ has an abnormality, the power generation permission is not notified. It is possible to avoid a dangerous state in which power generation is started despite abnormalities in the distributed power sources 7, 7 '.

If there is no notification from any of the distributed power sources 7 and 7 'due to a failure of the transmission / reception circuits 15a and 19 (see S17 in FIG. 4), the display 15 displays the distributed power source 7 without the notification. The state recognition of the commercial power supply 1 is set to "undefined"
Instead of notifying all the distributed power sources 7 and 7 ′ of the permission of the system interconnection power generation and the system separation power generation, all the distributed power sources 7 and 7 ′ may be in a standby state. As a result, since the state of one of the distributed power supplies 7 does not start generating while the state of one of the distributed power supplies 7 is “undefined”, the distributed power supply system 18 can be operated more safely.

[0025]

As described above, according to the first aspect of the present invention, a DC power supply, a power converter for converting a DC output from the DC power supply into an AC, and an abnormality / power failure of a commercial power supply are detected. Then, the power supply output from the power converter to the commercial power supply is stopped to separate the system, and when the abnormality of the commercial power supply / release of the power failure is detected, the system is connected to restart the power supply from the power converter to the commercial power supply. A distributed power supply including a distributed power supply having a grid connection protection device, a shared branch circuit supplied with power from a commercial power supply when the power grid is connected, and supplied with power from a power converter when the power grid is separated, and a plurality of distributed power supplies And a display for controlling the operation of each distributed power supply device.In the distributed power supply system, the display is provided when all the distributed power supplies recognize that the power supply of the commercial power supply is normal. Only when the distributed power source recognizes that the power supply of the commercial power source is abnormal, the distributed power source is given permission to generate power, and the distributed power source generates power only when the power generation permission is given. Since the grid-connected power generation and the system-separated power generation do not occur at the same time, it is possible to provide a distributed power supply system capable of operating a plurality of distributed power supply devices in parallel without damaging a commercial power supply or a distributed power supply. This has the effect.

In the invention according to claim 2, claim 1 is
In the distributed power supply system described above, if any of the distributed power supplies has an error, the display does not give permission to generate power to all of the distributed power supplies. This produces an effect that it is possible to avoid occurrence of a dangerous state such as generating power.

According to the third aspect of the present invention, there is provided the first aspect.
Alternatively, in the distributed power supply system according to claim 2, the display does not give permission for power generation to all the distributed power supplies when an error occurs in communication between any of the distributed power supplies and the display. Therefore, since the distributed power supply does not start power generation in a state where the state of the distributed power supply is not recognized by the display, it is possible to prevent power generation from being started without notification of a dangerous state. It works.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a distributed power supply system.

FIG. 2 is a flowchart illustrating an operation of a display unit of the distributed power supply system.

FIG. 3 is a flowchart showing an operation of a distributed power supply system according to another embodiment.

FIG. 4 is a flowchart showing an operation of the distributed power supply system according to another embodiment.

FIG. 5 is a schematic configuration diagram of a conventional distributed power supply device.

FIG. 6 is a schematic configuration diagram of a conventional distributed power supply system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Commercial power supply 7 Distributed power supply 8 Solar cell 9 Power converter 10 Grid-connected power converter 11 Off-line switch 12 System fan-shaped control circuit 13 House load 15 Display 15a Transmission / reception circuit 15b Operation control circuit 15c Display 15d Operation Unit 16 Shared branch circuit 17 Sensor unit 18 Distributed power system 19 Transmitter / receiver circuit 20 Outlet for shared branch circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirotada Higashihama 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor Shinichiro Okamoto 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works Co., Ltd. Tadayoshi 1048 Kadoma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. (reference) EB38 EB39 FF03 FF04 FF21 FF28 LL03

Claims (3)

[Claims] A DC power supply; a power converter for converting DC output from the DC power supply to an AC; and a system for stopping power supply output from the power converter to the commercial power supply when an abnormality / power failure of the commercial power supply is detected. A distributed power supply equipped with a grid connection protection device that performs grid connection and resumes power supply from the power converter to the commercial power supply when power supply is disconnected from the power supply and power failure is detected. A distributed power supply device having a shared branch circuit supplied with electric power from a commercial power supply and supplied with electric power from a power converter at the time of system separation, and a display device connected to a plurality of distributed power supply devices and controlling the operation of each distributed power supply device In the distributed power supply system that includes the following, the display recognizes that all the distributed power supplies recognize the power supply of the commercial power supply as normal and that all the distributed power supplies recognize the power supply of the commercial power supply as abnormal. Distributed power systems only, authorized power for distributed power, dispersion power, characterized in that to perform the power generation only when given permission to power generation when there. 2. The distributed power source according to claim 1, wherein the display unit does not give permission for power generation to all of the distributed power sources when any of the distributed power sources has an abnormality. system. 3. The display device according to claim 1, wherein when an error occurs in communication between any one of the distributed power sources and the display device, permission for power generation is not given to all of the distributed power sources. The distributed power supply system according to claim 1 or 2.