JP3319264B2 - Solar power system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic power generation system, and more particularly, to a photovoltaic power generation system having a distribution board connected to a commercial power supply.

[0002]

2. Description of the Related Art As one of the measures for preventing global warming caused by carbon dioxide, the development of a power generation system using solar cells in a house is progressing. This system uses the DC output of a solar cell as a power source to output an AC voltage, and uses the power while linking it to a commercial power supply.The distributed power system interconnection technical guideline issued by the Japan Electrical Association (Hereinafter referred to as guidelines) and the like, the technical guidelines are shown. This guideline states that the power supplied by commercial power will not be reduced in terms of quality, protection coordination, security, and reliability due to private power generation equipment such as interconnected solar power generation system,
This is for smooth interconnection.

[0003] For example, the one shown in the system configuration diagram of FIG. 2 is known. This solar power generation system 1
Is a solar cell 2, an inverter circuit 3a, and a parallel-off switch 3
and a distribution board 4 having a main breaker 4a and a branch breaker 4b. This means that the power from the commercial power source 5 is
First, it enters the distribution board 4 and branches after passing through the main breaker 4a, and is supplied to the load outlet 6 and the like through the branch breaker 4b. On the other hand, the DC power generated by the solar cell 2 is converted into AC by the inverter circuit 3a of the grid-connected inverter device 3, and is disconnected in the event of an abnormality or commercial power failure (opening the switch). R-phase R and T-phase T of single-phase three-wire wiring of commercial power supply via switch 3b
Is connected between the wiring lines. (This connected state is referred to as interconnection.) Then, the system interconnection type inverter device 3
Are connected and operated by outputting 200 V AC as a line voltage between an output terminal 3 e connected to the R phase R and 3 g connected to the T phase T. In addition, the grid-connected inverter device 3
Has an independent operation outlet 3d that is controlled to open and close by a switch 3c to output 100 V AC for power supply during a power failure.

The above-mentioned normal voltage at the time of interconnection means, in principle, a voltage between a power receiving point, that is, a line between three single-phase three wires near the primary side of the main breaker 4a, that is, a voltage between the R and N phases or a voltage between the T and N phases. Is 80 to 115 V, and the frequency 50 Hz area is 48.5 to 51.0 Hz, and the frequency 60 Hz area is 5
8.2 to 61.2 Hz. In addition, abnormal time means other than normal voltage at the time of interconnection, voltage rise, voltage drop,
Means frequency increase and frequency decrease. The grid-connected inverter device 3 has a function of detecting the abnormality and the power failure of the commercial power supply, detects the abnormality and the power failure of the commercial power supply for a certain period, controls the disconnecting switch 3b, and outputs the inverter output to the commercial power supply. 5 and electrically insulated. The open / close switch 3b is opened / closed by an excitation circuit 3b2 according to an open / close control signal output from the inverter circuit 3a.

[0005]

By the way, in the above-mentioned photovoltaic power generation system 1, when the commercial power supply system 5 is cut off by a disaster such as an earthquake, for example, an emergency power source such as communication equipment is required. The power supply to the load is inconvenient in that the wiring is reconnected to the independent operation outlet 3d provided in the grid-connected inverter device 3. In addition, this wiring is generally performed by using an extension cord or the like up to the grid-connected inverter device 3 installed at a remote place. Therefore, when a load having a large capacity is used, a voltage drop occurs, and the installation of the extension cord is not stable. As a result, the power supply itself lacked stability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solar panel having a distribution board section which effectively connects a grid and facilitates use of an emergency load during a power failure. It is to provide a photovoltaic power generation system.

[0007]

In order to achieve the above object, a photovoltaic power generation system according to a first aspect of the present invention provides a solar battery and a parallel disconnect switch by converting a DC voltage input from the solar battery into an AC. A power grid-connected inverter device that outputs power via a branch power supply, and a distribution board that inputs commercial power and branches and outputs the power through a branch breaker below the main breaker. The board is provided with a second disconnection switch controlled by an open / close control signal of the grid-connected inverter device, and an emergency branch circuit including a one-branch circuit for opening and closing a connection to a commercial power supply with the second disconnection switch. A branch circuit;
The second disconnection switch is connected in parallel with the branch breaker, is connected to the output of the grid-connected inverter, and opens and closes the connection between the commercial power supply and the grid-connected inverter. As a result, the output of the grid-connected inverter device is opened and closed by the second parallel-off switch, thereby forming a one-branch circuit.
It is connected to the emergency branch circuit by.

Further, in the photovoltaic power generation system according to a second aspect, the second parallel disconnecting switch according to the first aspect has a contact mechanism that closes when no excitation is performed. This allows
The second paralleling switch is not excited in the normal state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a solar power generation system according to the present invention will be described below with reference to FIG. FIG. 1 is a system configuration diagram of a solar power generation system 1 of the present invention.
The photovoltaic power generation system 1 includes a solar cell 2, a grid-connected inverter device 3, and a distribution board 4. The photovoltaic power generation system 1 is different from the conventional photovoltaic power generation system in two features, namely, the operation of the grid-connected inverter device 3 and the configuration of the distribution board 4.

The grid-connected inverter device 3 includes an inverter circuit 3a, a parallel-off switch 3b, a switch 3c,
Independent operation outlet 3d and output terminals 3e, 3f, 3
g. This inverter circuit 3a is also connected to the solar cell 2
In addition to converting the DC power generated by the DC power supply into an AC power, it has a function of detecting the abnormality at the time of interconnection and the power failure of the commercial power supply. When detecting an abnormality for a certain period, the inverter circuit 3a outputs an open / close control signal for opening the parallel-off switch 3b to open the circuit, and disconnects the output of the inverter circuit 3a from the commercial power supply 5. The disconnecting switch 3b is a switch having a two-pole contact circuit that opens and closes the connection between the R-phase and T-phase outputs of the inverter circuit 3a and the output terminals 3e and 3g. It is opened and closed. The output terminals 3e, 3f, 3g are connected to the grid-connected inverter device 3
And a single-phase three-wire wiring of the distribution board 4 described later. The output terminals 3e and 3g are connected to the single-phase 3
It is connected to the R-phase R and the T-phase T of the line wiring, and outputs 200 V AC as a line voltage. Output terminal 3f
Is an output terminal for connecting to N, which is the N phase of the single-phase three-wire wiring of the distribution board 4, and the switch 3c controls the inverter circuit 3a.
Is connected to the N-phase.

When the system interconnection type inverter device 3 detects a power failure for a certain period of time, the inverter circuit 3a keeps the disconnecting switch 3b closed, and activates a second disconnecting switch 4c described later. It outputs an open / close control signal. At the same time, the switch 3c1 of the switch 3c is closed to supply power during a power failure, and 100 V AC is output between the independent operation outlet 3d and the output terminals 3f, 3g.

The distribution board 4 has a main breaker 4a, a branch breaker 4b, a second parallel break switch 4c, and an emergency branch circuit 7 opened and closed by the second parallel break switch 4c. Second
The disconnecting switch 4c has a switch 4c1 and an excitation circuit 4c2, and is arranged in parallel with the branch breaker 4b. The opening / closing unit 4c1 has a contact mechanism that closes at the time of non-excitation, and is an opening / closing unit that opens and closes the R and R phases of the single-phase three-wire wiring, that is, the N and T phases that are the neutral and T phases. , Excitation circuit 4c2
Are opened by being excited. The excitation circuit 4c2 is
A circuit for opening and closing the opening / closing section 4c1. The opening / closing section 4c1 is opened by an excitation current which is an opening signal of an opening / closing control signal output from the inverter circuit 3a of the grid interconnection type inverter device 3. The emergency branch circuit 7 is a branch circuit for branching a power supply to an outlet or the like for using an emergency load, and includes an emergency branch breaker 4d. The emergency branch breaker 4d is connected to, for example, T, which is the T phase of single-phase three-wire wiring, and N, that is, N, which is a neutral wire.

The above-mentioned distribution board 4 is connected to the output terminals 3e, 3f, 3g of the system interconnection type inverter device 3 and the second parallel disconnecting switch 4c. 3e and N
The phase N is connected to 3f and the T phase T is connected to 3g. Then, the connection between the commercial power supply and the grid-connected inverter device is opened and closed by the second disconnection switch 4c.

Next, the operation of the photovoltaic power generation system having the above configuration will be described. When DC power is output from the solar cell 2, the DC power is first converted into AC power by the inverter circuit 3 a of the grid-connected inverter device 3. And
In a state where the disconnection switch 3b and the second disconnection switch 4c are connected to the commercial power supply system, that is, in an interconnected state,
The power output from the solar cell 2 together with the power from the commercial power supply 5 is supplied to the load outlet 6 and the emergency load of the emergency branch circuit 7 via the branch breaker 4b and the emergency branch circuit breaker 4d. And the inverter circuit 3
According to a, whether or not there is an abnormality (voltage increase, voltage decrease, frequency increase, and frequency decrease) in the vicinity of the second disconnection switch 4c, which is the connection point, based on the predetermined voltage range and the predetermined voltage frequency range described above. Is determined. Then, when it is determined that there is an abnormality, the disconnection switch 3b is opened. Further, when the power failure of the commercial power supply is detected by the inverter circuit 3a, the disconnecting switch 3b continues the closed state, and a control signal for opening the second disconnecting switch 4c, and a switching unit of the switch 3c. And a control signal for closing 3c1. As a result, at the time of a power failure, only the power output from the solar cell 2 is transmitted to the emergency branch circuit 7 via the emergency branch breaker 4d.
Applied to the emergency load.

In the above operation, the distribution board 4 of the photovoltaic power generation system 1 includes the second parallel-off switch 4c controlled by the switching control signal of the grid-connected inverter device 3;
1 minute when the connection to the commercial power supply is opened and closed by the disconnecting switch 4c
An emergency branch circuit 7 is provided by a branch circuit, and the second parallel disconnecting switch 4c is disposed in parallel with the branch breaker 4b and connected to the output of the grid-connected inverter device 3, thereby providing a grid-connected type. The output of the inverter device 3 is a second parallel-off switch 4c.
In the event of a commercial power failure, the output of the solar cell 2 is applied to the emergency load outlet of the emergency branch circuit 7. As a result, even when the commercial power supply is interrupted by a disaster such as an earthquake at home or the like, by connecting a load requiring power in an emergency such as a communication device such as a telephone or a fax to the outlet of the emergency branch circuit 7, And can be used without reconnection. In addition, by providing the second disconnecting switch 4c with a contact mechanism that closes when not energized, the closed state of the second disconnecting switch 4c is ensured in a state where it is not excited in a normal state. . Accordingly, electric power for operation for closing the second parallel-off switch 4c in a normal state becomes unnecessary, and
The loss of power is eliminated, and the contact state of the closed circuit is stable without being affected by the state of the operation power supply.

In the description of the above embodiment,
Second disconnecting switch 4c has been described as having a contact mechanism for closing at the time of non-excitation, the present invention is not limited only thereto. Furthermore, grid-connected inverter 3
Has a disconnection switch 3b having a two-pole contact circuit, and an output terminal 3f for a neutral conductor for outputting 100 V is connected to an outlet 3d for independent operation. The N-phase may be opened and closed with 3b having a three-pole contact circuit, and the output terminal 3f may be directly connected to the N-phase opening and closing pole.

[0017]

The solar power generation system according to claim 1 is
The output of the grid-connected inverter device is connected to an emergency branch circuit constituted by a single branch circuit that is opened and closed by a second parallel disconnecting switch, so that a power supply is required in an emergency such as a communication device such as a telephone or a fax machine . load by connecting to the emergency branch circuit that makes it possible to use without the recombinant tie.

Further, in the solar power generation system according to the second aspect, in addition to the effect of the first aspect, the second disconnecting switch is not excited in a normal state. Power for operation for closing is not required, and power loss is eliminated.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a system configuration diagram of a conventional example.

[Description of Signs] 1 Photovoltaic power generation system 2 Solar cell 3 Grid-connected inverter device 3b Off-line switch 4 Distribution board 4a Main breaker 4b Branch breaker 4c Second off-line switch 4d Emergency branch breaker 5 Commercial power supply 6 Load outlet 7 Emergency branch circuit

Continuation of the front page (72) Inventor Shinichiro Okamoto 1048 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Inside (56) References JP-A-2-7832 (JP, A) JP-A-62-53116 (JP, A (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 3/38 H02J 9/06 H02M 7/48

Claims (2)

(57) [Claims] 1. A solar cell, a grid-connected inverter device that converts a DC voltage input from the solar cell into AC and outputs the AC through a disconnecting switch, and a lower part of a main circuit breaker that receives a commercial power supply. A power distribution panel that branches and outputs a signal via a branch breaker on the side, wherein the power distribution panel is controlled by a switching control signal of a grid-connected inverter device to open and close the second off-line. And an emergency branch circuit with a one-branch circuit for opening and closing the connection to the commercial power supply with the second parallel-off switch. The second parallel-off switch is connected to the branch breaker. A photovoltaic power generation system, which is connected in parallel and connected to an output of the grid-connected inverter, and opens and closes a connection between a commercial power supply and the grid-connected inverter. 2. The photovoltaic power generation system according to claim 1, wherein the second off-switch has a contact mechanism that closes when not energized.