JPH1169632A - Solar power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar power generation system in which a parallel-off switch and a power converter are installed so as to be close, in which a signal line is made short, which increases noise resistant property and which prevents malfunctions. SOLUTION: In a system, a system interconnection operation is performed between a power converter 23, which converts a direct current to be output from a solar cell 20 into an alternating current and a commercial power supply AC. When a system-interconnection protective device 25 detects an abnormality or the power failure of a commercial power supply AC, it drives parallel-off switches 22a, 22b so as to perform a system splitting operation and to be reported to the power converter 23. A linkage breaker 21 is inserted across a main line Lm, which is connected to the commercial power supply AC via a master breaker 12 and the parallel-off switches 22a, 22b. The master breaker 12 and the linkage breaker 21 are housed in a distribution board 1, and the parallel-off switches 22a, 22b are housed in a box 2 as a body which is separated from a distribution board 1.

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 in which a power supply device using a solar cell is electrically connected to a commercial power supply to perform a system interconnection operation so as to supply power to a common load. Things.

[0002]

2. Description of the Related Art In recent years, as one of measures to prevent global warming due to carbon dioxide, a solar cell is installed in a house for private power generation, the electric power obtained by the solar cell is converted into electric power, and the system is connected to a commercial power supply. It is considered to perform system operation. That is, DC power output from a solar cell is converted into AC power using an inverter circuit, and a power transmission system is communicated with a commercial power supply to perform system interconnection. Technical guidelines for such grid-connected operation between private power generation and commercial power are shown in the Technical Guidelines for Distributed Power System Interconnection (hereinafter abbreviated as guidelines) issued by the Japan Electrical Association. Have been. This guideline ensures the quality, security, reliability, and protection coordination of power supplied by commercial power,
It is shown for smooth interconnection operation.

By the way, as a photovoltaic power generation system,
As shown in FIG. 8, an interconnection breaker 21 and a trunk line Lm connected from a single-phase three-line commercial power supply AC to a trunk line Lm connected via a current limiter (hereinafter referred to as a limiter) 11 and a main trunk breaker 12 composed of an earth leakage breaker. Off-line switches 22a, 2
In some cases, a power converter 23 for converting the output of the solar cell 20 into electric power is connected via the power converter 2b. The limiter 11 is a breaker provided to limit a load current of a customer to a value not more than a contract value with a power company. The power converter 23 uses the inverter circuit as described above, and has a function of converting a DC voltage output from the solar cell 20 into an AC voltage. A plurality of branch circuits Lb are connected to the trunk line Lm between the main breaker 12 and the interconnection breaker 21 via the branch breakers 13, respectively. Limiter 1
1, the main breaker 12, the branch breaker 13, the interconnection breaker 21, the disconnecting switches 22a and 22b are housed in the distribution board 1, the solar cell 20 is installed on the roof of a house, etc., and the power converter 23 is a solar cell. In order to make the wiring between them as short as possible, they are placed outdoors in a house. The reason why the wiring between the solar cell 20 and the power converter 23 is shortened and arranged outdoors is that a direct current flows between the solar cell 20 and the power converter 23 so that the loss does not increase. The maximum output voltage of the 20 is about 300 V, so that the possibility of the high voltage wiring touching a person is reduced and safety is improved.

The disconnecting switches 22a and 22b are provided to disconnect the commercial power supply AC from the power converter 23 in the event of an abnormality or a power failure of the commercial power supply AC. That is, the system interconnection is performed when the disconnection switches 22a and 22b are on, and the system is separated when the disconnection switches 22a and 22b are off (that is, in the disconnected state). According to the above guidelines, it is desirable that two contacts are inserted between the two systems for disconnecting switches 22a and 22b for system interconnection.

The disconnecting switches 22a and 22b are disconnected when an abnormality or a power failure of the commercial power supply AC is detected by the system interconnection protection device 25. Breaker 21 and disconnection switch 22
a and 22b are detected based on the output of the sensor 27 inserted between the first and second sensors 22a and 22b. That is, the sensor 27 detects the current flowing through the main line Lm and the voltage between the lines, and transfers the detected current to the system interconnection protection device 25, whereby an abnormality or a power failure can be detected. Since the paralleling switches 22a and 22b are inserted between the power converter 23 and the branch breaker 13, power is supplied to the branch circuit Lb at the time of abnormality or power failure even if the solar cell 20 generates power. You can't do that. Therefore, the power converter 23 and the parallel-off circuit breaker 22
It has been proposed to connect a shared branch circuit Lc between the common branch circuit Lc and the common branch circuit Lc via the common branch breaker 24. If such a common branch circuit Lc is provided, power can be supplied to the common branch circuit Lc regardless of whether the system is connected to the system or separated from the system. In other words, power can be supplied to the shared branch circuit Lc even when an abnormality or power failure occurs, as long as the output is normally obtained from the power converter 23. As a result, there is a high possibility that power can be supplied to a load that needs to supply power preferentially, such as a communication device such as a telephone.

[0006]

In the above-described photovoltaic power generation system, since the disconnecting switches 22a and 22b are housed in the distribution board 1, the grid connection protection device 25 is also provided in the distribution board 1. It will be stored in. Grid connection protection device 2
5 is a power converter 2 depending on whether the system is connected or disconnected.
3 has a function of notifying the power converter 23 of system interconnection or system separation so that the corresponding operation is performed. A signal line Ls is provided between the system interconnection protection device 25 and the power converter 23.
Connected by Therefore, the parallel-off switches 22a, 22
When 2b is arranged in distribution board 1, signal line Ls between power converter 23 arranged near solar cell 20 becomes long, and there is a problem that noise resistance is reduced. That is, the power converter 23 may erroneously recognize whether the system is connected to the system or separated from the system, and may cause a malfunction.

The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to dispose a disconnecting switch and a power converter in close proximity, to shorten a signal line, and to reduce noise. An object of the present invention is to provide a photovoltaic power generation system which has improved performance and prevents malfunction.

[0008]

According to the first aspect of the present invention, there is provided a solar cell, a power converter for converting a direct current output from the solar cell to an alternating current, and a main line connected to a commercial power supply and a power converter. A disconnecting switch inserted between them to switch between system interconnection and system separation; a shared branch circuit that supplies power to the load from the power path between the power converter and the disconnecting switch; When a power failure is detected, the system disconnection switch is driven to separate the system and notify the power converter of the system interconnection, a trunk line connected to the commercial power supply via at least the main breaker, and the trunk line is disconnected. An interconnection breaker inserted between the switch and the main switch is provided, the main breaker and the interconnection breaker are housed in a distribution board, and the off-switch is arranged outside the distribution board. According to this configuration, the distance between the power converter arranged close to the solar cell and the disconnection switch can be reduced by providing the disconnection switch outside the distribution board, and as a result, By reducing the distance between the power grid and the power grid, the signal line between the grid protection power grid and the power converter can be shortened. Is higher.

According to a second aspect of the present invention, in the first aspect of the present invention, the power converter is configured to increase the output voltage from the time of system interconnection when the power system is separated, and the power converter is connected between the power converter and the common branch circuit. Is provided with a switching switch. The switching switch has a first contact for connecting the first output line of the power converter to the shared branch circuit when the system is separated, and an output of the first output line of the power converter. The second contact connecting the second output line of the power converter that divides the voltage and outputs the divided output to the shared branch circuit at the time of system interconnection, and the first contact and the second contact are simultaneously turned on. And interlock means for performing interlock so as to prevent the interlock. According to this configuration, the interlock means is provided to prevent the first contact and the second contact inserted between the power converter and the common branch circuit from being simultaneously turned on. It is possible to reliably prevent the first contact and the second contact from being simultaneously turned on, and to prevent a short circuit between the two output lines of the power converter.

According to a third aspect of the present invention, in the first aspect of the present invention, when the system interconnection protection device detects abnormality or cancellation of a power failure, the system automatically returns to the system interconnection operation.
According to this configuration, the system is separated due to an abnormality or a power failure, but when the system recovers from the abnormality or the power failure, the system automatically returns to the system interconnection operation.

According to a fourth aspect of the present invention, in the first aspect of the present invention, an interconnection protection panel containing a disconnecting switch and a system interconnection protection device and a box containing a power converter are connected to a distribution board. Is provided separately and houses a common branch breaker inserted into the common branch circuit in the interconnection protection panel. According to this configuration, since the disconnecting switch and the grid connection protection device are housed in the grid protection panel and the power converter is housed in the box, the grid connection protection device and the power converter are relatively separated. While being arranged close to each other, the interconnection protection panel can be arranged indoors separately from the box that is generally installed outdoors.
In addition, since the common branch breaker is stored in the interconnection protection panel, if the interconnection protection panel is placed indoors, the common branch breaker can be operated indoors and returned when the common branch breaker is cut off. Becomes possible.

According to a fifth aspect of the present invention, in the second aspect of the present invention, the parallel-off switch and the switching switch are each configured by combining a relay having two normally open contacts. According to this configuration, since the parallel-off switch and the switching switch are configured only by the relays each having two normally-open contacts,
The parallel-off switch and the switching switch can be constituted only by relatively inexpensive relays, and the number of parts can be reduced. As a result, the overall cost can be reduced.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the three output lines of the power converter are connected to the main line connected to the single-phase three-wire commercial power supply via a disconnecting switch. Among them, the common branch circuit is connected to the output line connected to the neutral line of the main line and the other two output lines respectively, and the voltage applied to each common branch circuit is individually controlled in the power converter. Things. According to this configuration, the output voltage of the power converter is not changed between the time of system interconnection and the time of system separation,
Since the line voltage of the common branch circuit of the system is individually controlled in the power converter, a switching switch is not required and the contact configuration is simplified.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) The basic configuration of the present embodiment is the same as the conventional configuration shown in FIG. 8, and, as shown in FIG. 1, the disconnection switches 22a and 22b are provided separately from the distribution board 1. Box 2
The main difference is that they are stored inside.

That is, similar to the conventional configuration, the limiter 1
The power converter 23 is connected to the trunk line Lm connected to the commercial power supply AC via the main power supply 1 and the main breaker 12 via the interconnection breaker 21 and the disconnecting switches 22a and 22b. The power converter 23 converts the DC output of the solar cell 20 into AC similar to the commercial power AC, and has an inverter circuit as a main configuration. A plurality of branch circuits Lb are connected to the trunk line Lm between the main breaker 12 and the interconnection breaker 21 via the branch breakers 13, respectively.

By the way, the limiter 11, the main breaker 1
2. The branch breaker 13 and the interconnection breaker 21 are housed in the distribution board 1 in the same manner as in the conventional configuration, but the disconnection switches 22a, 2
In this embodiment, a power converter 2b is provided outside the distribution board 1 in this embodiment.
3 and united together with the system interconnection protection device 25 and stored in the box 2. This box 2 is usually arranged outdoors near the solar cell 20 so that the loss of DC power in the path from the solar cell 20 to the power converter 23 is reduced. The power converter 23 and the parallel-off switch 22a,
The common branch circuit Lc is connected to the common branch circuit 22b via the common branch breaker 24.

The system interconnection protection device 25 is connected to the interconnection breaker 21.
An abnormality or a power failure is detected based on the output of the sensor 27 inserted between the switching switches 22a and 22b. Sensor 2
7 includes a current sensor for detecting a current flowing through the main line Lm, and a voltage sensor for detecting a voltage between the lines of the main line Lm.
By passing the detected values of the current and the voltage to the grid interconnection protection device 25, the grid interconnection protection device 25 detects the fluctuation of the voltage and the fluctuation of the frequency, and if there is any abnormality, disconnects the disconnection switches 22a and 22b. Disconnect. Further, a power failure of the commercial power supply AC can be detected based on changes in voltage and current.

Incidentally, the power converter 23 is configured to output an AC of 200 V (when the commercial power supply is 100 V) when the power system is interconnected, and to output an AC of 100 V when the power system is separated. Whether the system interconnection state or the system separation state is indicated by a notification signal from the system interconnection protection device 25 through the signal line Ls. The power converter 23 divides the output into equal parts, and connects the divided midpoint to the neutral line of the main line Lm during system interconnection. The reason why the output voltage of the power converter 23 is switched between the time of system interconnection and the time of system separation is to secure current capacity by lowering the output voltage because only the solar cell 20 is used as a power source during system separation. As described above, since the output voltage of the power converter 23 changes between the time of system interconnection and the time of system isolation, in order not to change the line voltage of the shared branch circuit Lc between the time of system interconnection and the time of system isolation, Means for switching the connection relationship between the power converter 23 and the shared branch circuit Lc is required. Therefore, diverter switch 2 comprising a contact r _21, r ₂₂ of the change-over switch 29a and the two-pole comprising a contact r ₁₁ ~r ₁₃ three-pole
9b is provided between the power converter 23 and the common branch breaker 24. Here, the parallel-off switches 22a, 22
b and the switching switches 29a and 29b are constituted by electromagnetic relays.

[0019] is controlled by the switching signal from the switching switch 29a of the contact r ₁₁ ~r ₁₃ and diverter switch 29b contacts r _21, the power so as not to turn on at the same time the r ₂₂ converter 23. Diverter switch 29a each contact r ₁₁ ~ between the 3 lines from 3 lines and disconnecting switch 22b from the power converter 23
It is intended to insert the r _13, all of the contacts r ₁₁ ~r ₁₃ are inserted into the same path. Here, in FIG. 1, the output lines from the power converter 23 are referred to as a line, b line, and c line from the top. One contact r ₂₂ of the change-over switch 29b is connected in parallel with the contact r ₁₃ inserted in the line c of the contact r ₁₁ ~r ₁₃ of the change-over switch 29a. Also, other contact r ₂₁ of the change-over switch 29b is connected to one end between the contact point r ₁₁ and power converter 23 inserted in a line of contact r ₁₁ ~r ₁₃ of the change-over switch 29a, b the other end is connected between the contact point r _12, which is inserted in line with the shared branch breakers 24.

In short, the common branch breaker 24 is connected to one of the power line and the neutral line of the main line Lm at the time of system interconnection, and the line voltage between the line a and the line c is 100 V at the time of system separation. contact r _21, r ₂₂ is inserted from becomes between the diverter switch 29b is shared branch breakers 24 and a line and c-line, the line voltage between a line and c-line at the time of system interconnection is 200V , The switching switch 29a is connected to the b-line and c
Contacts r ₁₂ and r ₁₃ are inserted between the line and the common branch breaker 24. In other words, the common branch breaker 24 is connected to the b-line and the c-line at the time of system interconnection,
One end of the common branch breaker 24 must be selectively connected to one of the a-line and the b-line when the system is interconnected and when the system is separated. That is,
Must be prohibited from simultaneously turned on and the contact point r ₂₁ of the contacts r ₁₂ and diverter switch 29b of the change-over switch 29a. If both contacts r ₁₂ and r ₂₁ are turned on at the same time, a problem arises that the a-line and the b-line are short-circuited.

Both switching switches 29a and 29b are connected to a contact r.₁₁~
r₁₃, R_{twenty one}, R_{twenty two}Are all a contacts (normally open contacts),
If there is no switching signal from power converter 23, it is turned off.
Contact r₁₂And contact point r_{twenty one}And are not turned on at the same time.
Therefore, at the time of system interconnection, the contact r of the switching switch 29a₁₁
~ R₁₃Is turned on, and the contact r of the switching switch 29b is turned on._{twenty one}, R _{twenty two}
Is turned off. Also,
Contact r at the time of separation₁₁~ R₁₃Is turned off and the contact r_{twenty one}, R
_{twenty two}Turns on.

On the other hand, when no abnormality or power failure is detected in the interconnection protection device 25 monitoring the output of the sensor 27, the interconnection protection device 25 converts the notification signal for notifying the abnormality or the cancellation of the power failure to power conversion. To the vessel 23. At the same time, system disconnection is instructed to the parallel-off switches 22a and 22b to turn on the contacts. When the power converter 23 receives the notification signal notifying the abnormality or the cancellation of the power failure, the switching switch 29a
The contact r ₁₁ ~r ₁₃ on and off the contact point r _21, r ₂₂ of the change-over switch 29b. This switching is performed automatically.

The switching switches 29a, 29b are
To ensure that the contacts do not turn on at the same time,
Interlocks the contacts of the switching switches 29a and 29b
It is desirable. The interlock uses electrical
Interlock and mechanical interlock by contact configuration
It is thought that. To perform electrical interlock
Is configured as shown in FIG. 2, for example. In this configuration,
Equipped with two a contacts (normally open contacts) as switching switches 29b
Parallel relays 22a, 22b
And the switching of the switching switch 29a is performed.
Point r₁₁~ R₁₃When the switch is turned off, the switching switch 29b
Of the drive coil Cb. One
In other words, the parallel-off switches 22a and 22b and the switching switch 29
a is an auxiliary contact r which is a b contact (normally closed contact)₃₁~
r ₃₃And these auxiliary contacts r₃₁~ R₃₃And switchgear
A switching signal is given to a series circuit with the drive coil Cb of 29b.
Contact r of the switching switch 29b_{twenty one}, R_{twenty two}Open and close
It is. Off-line switches 22a and 22b and switching switch 2
9a is an auxiliary contact r₃₁~ R₃₃All contacts are a contacts except
Consists of points.

When the disconnection switches 22a and 22b perform system separation, the auxiliary contacts r ₃₁ and r ₃₂ are turned on. At this time, a notification signal is given to the power converter 23 and the output voltage of the power converter 23 becomes 100V. Can be switched. Switching switch 2
9a turns off the contact r ₁₁ ~r ₁₃ of receiving the diverter switch 29a the notice signal from the system interconnection protection device 25, as a result, auxiliary contacts r ₃₃ is turned on. That is, the driving coil C
connected in series of three auxiliary contacts r ₃₁ ~r ₃₃ was is all turned on b. At this time, a switching signal is given from the power converter 23 to the coil Cb of the switching switch 29b, and the auxiliary contact r
₃₁ is energized the driving coil Cb through ~r _33, is the contact point r _21, r ₂₂ is turned on. Since the contact r ₁₁ ~r ₁₃ of the change-over switch 29a in the configuration of FIG. 2 is an auxiliary contact r ₃₃ If off does not turn on, the contacts r of the contact r ₁₁ ~r ₁₃ and diverter switch 29b of the change-over switch 29a _21, and r ₂₂ can be prevented from becoming oN simultaneously, it is possible to prevent a short circuit between a line and the line b. Here, the prevention of the short circuit between the a-line and the b-line must be performed also at the time of system interconnection, and therefore, the auxiliary contacts r ₃₁ , of the parallel-off switches 22a, 22b.
r ₃₃ also are connected in series to the driving coil Cb. That is, since the contact r ₂₁ is never turned on, which is inserted between the disconnection switch 22a, a wire and b wire if not performed strains isolated by 22b, and a line This also b A short circuit with the wire is reliably prevented.

On the other hand, to perform the mechanical interlock,
What is necessary is just to employ | adopt the structure like FIG. This is switching open / close
Instead of providing the devices 29a and 29b, two a contacts r₄₁,
r₄₂And one b contact r₄₃Switching switch 29 having
It is provided. Here, the operation of the circuit configuration shown in FIG.
As is clear from the work, both switching switches 29a, 29b
Contact r₁₃, R_{twenty two}Are not turned on at the same time,
Even if they are on, there is no change in the electrical connection relationship.
In the configuration shown in FIG.₁₃, R_{twenty two}Contact points corresponding to are omitted
I have. Also, the contact r of the switching switch 29a₁₁Is the grid
Because it is on when the system is off and off when the system is separated,
The corresponding contact r₄₁And a contact r₁₂Contact with
Point r_{twenty one}Contact r as a contact corresponding to₄₂, R₄₃With
is there. That is, both contact points r₄₂, R₄₃At one end
Connected to one end of the ₄₂The other end is a power converter
Of the 23 output lines, the contact r₄₃The other end of
The output line of the power converter 23 is connected to the line a.
Here, the contact r₁₂And contact point r _{twenty one}Is turned on at the same time
Is prohibited, the contact r₄₂Is a contact, contact r₄₃B contact
Interlock is performed by setting
You.

(Embodiment 2) In Embodiment 1, the disconnection switches 22a and 22b and the power converter 23 are housed in the box 2, but in this embodiment, as shown in FIG. 22a, 22b, the system interconnection protection device 25, the common branch breaker 24, and the sensor 27 are housed in the interconnection protection panel 4 separate from the distribution board 1 and the box 2a, and the power converter 23 is installed in the box 2a. And switching switches 29a and 29b.

In this configuration, the signal line Ls between the system interconnection protection device 25 and the power converter 23 is longer than in the first embodiment, but can be shorter than in the conventional configuration. . Moreover, since the box 2a containing the power converter 23 is arranged near the solar cell 20, it is generally arranged outdoors, but the interconnection protection panel 4 can be arranged indoors. If the interconnection protection panel 4 is arranged indoors, when the common branch breaker 24 is cut off, the common branch breaker 24 can be operated and restored indoors to facilitate the operation. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3) In Embodiment 1, the one having three a-contacts is used as the disconnecting switches 22a and 22b and the switching switch 29a. However, as shown in FIG. In this example, the parallel-off switches 22a and 22b and the switching switches 29a and 29b are constituted only by electromagnetic relays having two a contacts. In the configuration of the first embodiment shown in FIG. 1, electromagnetic relays each having three a contacts are used as the disconnection switches 22a and 22b.
In the present embodiment, an electromagnetic relay having two a-contacts is used. According to the guideline, two contacts are provided between two systems that perform system interconnection. By inserting two contacts of each of the parallel-off switches 22a and 22b into the two wires connected to Lc, the guideline can be satisfied for two of the three wires.

On the other hand, in the configuration of the first embodiment shown in FIG. 1, since the switching switch 29a has three a-contacts, if this is to be constituted by an electromagnetic relay having two a-contacts, A set of electromagnetic relays is required. Therefore, two switching switches 29a ₁ and 29a which are simultaneously turned on and off are provided.
₂ is provided, and the output line of the power
Contacts r ₁₁₁ , r of the switching switches 29a ₁ , 29a _2
112 are inserted in series, and each switching switch 29a ₁ , 29a ₂
Inserting the remaining contacts r _121, r ₁₂₂ to the b line and c-line, respectively. With this configuration, the disconnection switches 22a, 22
two contacts r _111, r _{11 2} of b of diverter switch 29a ₁ also 1 line contact is not inserted, 29a ₂ is to satisfy the guideline will be inserted.

By adopting the above-mentioned contact configuration, two a contacts are provided while satisfying the guideline of inserting two contacts into the electric circuit connecting the two systems for system interconnection. Can be configured with only electromagnetic relays,
The cost can be reduced as compared with the case where a special electromagnetic relay having three a contacts is used. Also,
Since the two parallel switches 22a and 22b and the two switching switches 29a ₁ and 29a ₂ are simultaneously turned on and off at the same time, the control of the contacts is the same as in the first embodiment shown in FIG.

If only the guidelines are satisfied, FIG.
As shown in FIG. 1, with respect to the configuration of the first embodiment shown in FIG. 1, only one of the disconnecting switches 22a may be configured by an electromagnetic relay having two a contacts. Other configurations and operations are the same as those of the first embodiment. (Embodiment 4) In Embodiment 1, the output voltage of the power converter 23 is changed between when the system is connected and when the system is separated. However, in the present embodiment, the output voltage is changed between when the system is connected and when the system is separated. The output voltage of the power converter 23 is not changed. Such a configuration can be adopted when the power generated by the solar cell 20 has a sufficient margin with respect to the power consumption of the load connected to the shared branch circuit Lc. And b line, and between b and c lines, shared branch circuits Lca and Lcb via shared branch breakers 24a and 24b, respectively.
Are connected. As shown in FIG. 7, the configuration of the present embodiment does not require the switching switches 29a and 29b, so that the configuration of the contacts is simplified. In addition, two shared branch circuits Lc
a, Lcb, both shared branch circuits Lca, Lca,
In order to suppress the fluctuation of the output voltage of the power converter 23 due to the load connected to Lcb, each of the shared branch circuits Lca, Lca
Voltage control is individually performed for each output line connected to cb. Other configurations and operations are the same as those of the first embodiment.

[0032]

According to the first aspect of the present invention, there is provided a solar cell, a power converter for converting DC output from the solar cell into AC,
A disconnection switch inserted between the mains connected to the commercial power supply and the power converter to switch between system interconnection and system isolation;
A shared branch circuit that supplies power to the load from the electric circuit between the power converter and the disconnecting switch, and a power disconnector that drives the disconnecting switch to separate the system when an abnormality or a commercial power failure is detected. A mains connected to the commercial power supply via at least the main breaker, and a mains breaker inserted between the mains and the disconnecting switch. The breaker is housed in the distribution board, and the disconnecting switch is located outside the distribution board.Since the disconnecting switch is provided outside the distribution board, it is placed close to the solar cell. The distance between the power converter and the disconnecting switch can be reduced, and as a result, the distance between the power grid and the grid connection protection device that drives the disconnecting switch can be reduced. The signal line between the protection device and the power converter can be shortened, There is an advantage in that noise resistance is high.

According to a second aspect of the present invention, the power converter is configured to increase the output voltage from the time of system interconnection when the system is separated, and a switching switch is provided between the power converter and the common branch circuit. The switching switch is provided to divide the output voltage of the first output line of the power converter from the first contact connecting the first output line of the power converter to the shared branch circuit when the system is separated. The second contact connecting the second output line of the output power converter to the shared branch circuit during system interconnection and the first contact and the second contact are prevented from being simultaneously turned on. In the case where an interlock means for performing a lock is provided, an interlock is provided to prevent the first contact and the second contact inserted between the power converter and the common branch circuit from being simultaneously turned on. Since the locking means is provided, the first contact and the second contact are The sometimes become on reliably prevented,
There is an advantage that a short circuit between two output lines of the power converter can be prevented.

According to the third aspect of the present invention, when the system interconnection protection device detects abnormality or cancellation of a power failure, the system is automatically returned to the system interconnection operation. When the system is restored from an abnormality or a power failure, the system automatically returns to the system interconnection operation. Therefore, there is an advantage that there is no trouble in performing the restoration operation. According to a fourth aspect of the present invention, the interconnection protection panel containing the disconnecting switch and the system interconnection protection device and the box containing the power converter are provided separately from the distribution board, and the common branch is provided. In the case where the common branch breaker inserted in the circuit is stored in the interconnection protection panel, the disconnecting switch and the system interconnection protection device are stored in the interconnection protection panel, and the power converter is stored in the box. Although the grid connection protection device and the power converter are arranged relatively close to each other, the grid protection panel can be placed indoors separately from the box that is generally installed outdoors, and Since the common branch breaker is housed in the interconnection protection panel, if the interconnection protection panel is placed indoors, the common branch breaker can be operated indoors and returned when the common branch breaker is cut off There is an advantage of becoming.

According to the fifth aspect of the present invention, in the case where the parallel-off switch and the switching switch are each configured by combining a relay having two normally-open contacts, two relays each having two normally-open contacts are provided. Since the disconnecting switch and the switching switch are constituted only by the relays, the disconnecting switch and the switching switch can be constituted only by relatively inexpensive relays, and the number of parts can be reduced. This has the advantage that the overall cost can be reduced.

According to the sixth aspect of the present invention, of the three output lines of the power converter connected to the main line connected to the single-phase three-wire commercial power supply via the disconnecting switch, the main line is connected to the main line. In the case where a common branch circuit is connected to each of the output line connected to the neutral conductor and the other two output lines, and the voltage applied to each common branch circuit is individually controlled in the power converter, a system connection is used. The output voltage of the power converter is not changed between the system and the system separation, and the line voltage of the two shared branch circuits is individually controlled in the power converter. This has the advantage of simplifying the contact configuration and consequently facilitating contact control.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is a main part circuit diagram showing a modification of the above.

FIG. 3 is a main part circuit diagram showing another modification of the above.

FIG. 4 is a circuit diagram showing a second embodiment.

FIG. 5 is a main part circuit diagram showing a third embodiment.

FIG. 6 is a main part circuit diagram showing an application example.

FIG. 7 is a circuit diagram showing a fourth embodiment.

FIG. 8 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 2 Box 2a Box 4 Interconnection Protection Panel 12 Main Breaker 20 Solar Battery 21 Interconnection Breaker 22a, 22b Disconnecting Switch 23 Power Converter 24 Shared Branch Breaker 25 System Interconnection Protection Device 29a, 29b Switching Switch AC Commercial Power Lm Trunk line Lc shared branch circuit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirotada Higashihama 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Inventor Hiroaki Yuasa 1048 Odaka Kazuma Kadoma City, Osaka Pref. (72) Inventor Hiroyuki Ohno 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Eiji Iwami 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. Matsushita Electric Works Co., Ltd., 1048 Kadoma, Kadoma, Osaka Prefecture (72) Inventor Shinichiro Okamoto 1048 Kadoma, Kazuma, Kadoma, Osaka Pref.

Claims (6)

[Claims] 1. A solar cell, a power converter for converting a direct current output from the solar cell into an alternating current, and a system interconnection and a system separation inserted between a mains line connected to a commercial power supply and the power converter. Switch that switches the power, a shared branch circuit that supplies power to the load from the power path between the power converter and the disconnector, and drives the disconnector when an abnormality or commercial power failure is detected. System protection device that separates the system and notifies the power converter, a main line connected to the commercial power supply via at least the main breaker, and a grid inserted between the main line and the disconnect switch. A photovoltaic power generation system comprising a breaker, wherein the main breaker and the interconnection breaker are housed in a distribution board, and wherein the disconnecting switch is arranged outside the distribution board. 2. The power converter is configured to raise the output voltage from the time of system interconnection when the power system is separated, and a switching switch is provided between the power converter and the common branch circuit. A first contact for connecting the first output line of the power converter to the shared branch circuit at the time of system separation, and a second contact of the power converter for dividing and outputting the output voltage of the first output line of the power converter. 2
A second contact for connecting the output line to the shared branch circuit at the time of system interconnection, and interlock means for performing interlock so as to prevent the first contact and the second contact from being simultaneously turned on. The photovoltaic power generation system according to claim 1, wherein the photovoltaic power generation system is provided. 3. The photovoltaic power generation system according to claim 1, wherein when the grid connection protection device detects abnormality or cancellation of the power failure, the system automatically returns to the grid connection operation. 4. An interconnection protection panel containing a disconnecting switch and a system interconnection protection device, and a box containing a power converter are provided separately from a distribution board, and inserted into a common branch circuit. The photovoltaic power generation system according to claim 1, wherein the common branch breaker is housed in an interconnection protection panel. 5. A disconnect switch and a switching switch each having two switches.
The photovoltaic power generation system according to claim 2, wherein the photovoltaic power generation system is configured by combining relays each having a normally open contact. 6. A power line connected to a main line connected to a single-phase three-wire commercial power supply via a disconnecting switch is connected to a neutral line of the main line among three output lines of the power converter. Output line and the other two
The photovoltaic power generation system according to claim 1, wherein a common branch circuit is connected to each of the output lines, and a voltage applied to each common branch circuit is individually controlled in the power converter.