JPH1169661A - Solar light power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar light power generation system whose safety is increased by a method, wherein whether a common branch circuit is to be electrified or not in a system splitting operation is selected by a manual operation. 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 the commercial power supply AC, it drives parallel-off switches 22a, 22b so as to perform a system splitting operation, and it stops the supply of electric power to a common branch circuit Lc from the power converter 23. When an operating switch SW is operated by a manual operation in the system splitting operation, the supply of the electric power to the common branch circuit Lc from the power converter 23 is resumed.

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 switch 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]

By the way, in the above-mentioned photovoltaic power generation system, at the time of abnormality or power failure, the grid interconnection protection device 25 only separates the system by the disconnecting switches 22a and 22b. In the event of a power outage, power is automatically supplied from power converter 23 to shared branch circuit Lc.

However, when an abnormality or a power failure occurs due to a disaster, there is a possibility that a short circuit or disconnection of the wiring system has occurred. If power is supplied to the shared branch circuit Lc without checking the wiring system after disconnection, It may not be possible to ensure sufficient safety. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photovoltaic power generation system with enhanced safety by manually selecting whether to supply power to a common branch circuit when the system is separated. To provide.

[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 outage is detected, a grid connection protection device that drives the disconnection switch to separate the system and stop the power supply from the power converter to the shared branch circuit, and to share the power from the power converter manually when the system is separated An operation switch for restarting power supply to the branch circuit. According to this configuration, when an abnormality or a commercial power failure occurs, the power is disconnected by the disconnecting switch. However, if power is generated by the solar cell, power can be supplied from the power converter to the shared branch circuit. . However, power is not automatically supplied from the power converter to the shared branch circuit when the system is separated, but the power supply from the power converter to the shared branch circuit is temporarily stopped when the system is separated and the operation switch is turned on. When operated, the power supply from the power converter to the common branch circuit is restarted, so when the system is separated due to an abnormality or power failure, check the safety and then operate the operation switch, Safety can be improved.

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, there is provided a box accommodating the parallel-off switch, the power converter, and the system interconnection protection device, and an operation unit including an operation switch is separate from the box. It is provided on the body. According to this configuration, since the operation unit can be arranged in a place different from the disconnecting switch and the power converter, for example, in order to shorten an electric path between the power converter and the solar cell, the box is placed outdoors. Even when the operation unit is installed in a room, operability is facilitated by arranging the operation unit indoors.

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 this embodiment is the same as the conventional configuration shown in FIG. 8, and as shown in FIG. 1, an operation unit 22 for manual operation is provided in a system interconnection protection device 25. This is the main difference.

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 state is the system interconnection state or the system separation state is indicated by a notification signal from the system interconnection protection device 25. 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. So 3
Is provided with a switching switch 29b comprises a diverter switch 29a and the contact r _21, r ₂₂ of the two-pole comprising a contact r ₁₁ ~r ₁₃ poles between the common branch breakers 24 and power converter 23. Here, the paralleling switches 22a and 22b and the switching switch 2
9a 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~ R₁₃Turns off. Where
The power converter 2 according to the notification signal from the interconnection protection device 25
At the stage when the switching signal is generated from No. 3, the contact r_{twenty one}, R_{twenty two}Is
It is kept off as in the case of grid connection, and is a shared branch circuit.
No power is supplied to Lc. Also during this period
Since no power is supplied from the power converter 23, the power converter
It is also desirable to stop the operation of DC-AC conversion by 23.
New

In this embodiment, an operation switch SW for performing a manual operation is provided, and when the operation restart is instructed by operating the operation switch SW, the contact r of the switching switch 29b is switched.
_21, r ₂₂ switching signal is given to turn on. When the operation of the power converter 23 is stopped, the operation is restarted by an operation restart instruction from the operation switch SW. In this way, the power supply to the common branch circuit Lc is stopped until there is an instruction from the operation switch SW. Since the power supply can be instructed, safety is enhanced.

As described above, in the event of an abnormality or a power failure, after the supply of power to the common branch circuit Lc is stopped, the operation switch SW is operated to supply power from the power converter 23 to the common branch circuit Lc. Will be possible. 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 sends a notification signal notifying the abnormality or the cancellation of the power failure to the power converter 23. give. At the same time, the paralleling switches 22a, 22
Instruct the system interconnection to b to turn on the contact. The power converter 23 turns on the contact point r ₁₁ ~r ₁₃ of the receiving a notification signal for notifying the cancellation of abnormal or power failure diverter switch 29a, to turn off the contact point r _21, r ₂₂ of the change-over switch 29b.
This switching operation is automatically performed irrespective of the operation switch SW.

Incidentally, the switching switches 29a and 29b
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. Here, if the operation switch SW is operated,
A switching signal is given to the coil Cb of the switching switch 29b,
Is energized the driving coil Cb through auxiliary contacts r ₃₁ ~r _33, it 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, diverter switch 29
contact r ₂₁ of the contact r ₁₁ ~r ₁₃ and diverter switch 29b of a, r
₂₂ can be prevented from being turned on at the same time, and a short circuit between line a and line b can be prevented. Here, since the short-circuit prevention between the a-line and the b-line must be performed also at the time of system interconnection, the auxiliary contacts r ₃₁ and r _{33 of the} parallel-off switches 22a and 22b are also connected in series to the drive coil Cb. is there. That is, if system separation is not performed by the paralleling switches 22a and 22b, the contact r inserted between the line a and the line b
_{Because 21} never turns on, this also
The short circuit between the line and the b line 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. In addition, when this configuration is adopted, the two contact points r₄₂, R₄₃The same
Because it cannot be turned off sometimes, the grid connection protection device
DC-AC by the power converter 23 with the notification signal from
Stop the conversion operation and operate the operation switch SW
The operation of the power converter 23 is restarted.

(Second Embodiment) In the first embodiment, an instruction is given to the power converter 23 from the operation switch SW. However, in the present embodiment, as shown in FIG. Is provided with an operation switch SW, and the operation unit 3 is connected to the system interconnection protection device 25. The operation unit 3 includes a display DP composed of a liquid crystal display in addition to the operation switch SW, and a display mode changeover switch S for switching the display content of the display DP.
It is equipped with a W _1. The display DP is capable of displaying an instantaneous power amount, a used power amount, an integrated power amount, and the like calculated based on the current and the voltage detected by the sensor 27. In the present embodiment, an instruction to restart the operation is given to the power converter 23 through the grid interconnection protection device 25.
A switching instruction is given to 9a and 29b through the power converter 23. 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. From the power supply to the shared branch circuit, and an operation switch to manually restart the power supply from the power converter to the shared branch circuit during system separation, The power is not automatically supplied from the power converter to the common branch circuit, but the power supply from the power converter to the common branch circuit is temporarily stopped when the system is separated, and the power is turned off when the operation switch is operated. Since the power supply from the converter to the common branch circuit is restarted, when the system is separated due to an abnormality or power failure, it is necessary to operate the operation switch after confirming safety. Te, there is an advantage that safety can be improved.

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, there is provided a box including a disconnection switch, a power converter, and a system interconnection protection device, wherein an operation unit including an operation switch is provided separately from the box. Since the operation unit can be arranged in a place different from the disconnecting switch and the power converter, for example, a box is installed outdoors to shorten the electric path between the power converter and the solar cell. Even in such a case, there is an advantage that operability is facilitated by disposing the operation unit indoors.

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 3 Operation unit 20 Solar cell 22a, 22b Off-line switch 23 Power converter 25 Grid connection protection device 29a, 29b Switching switch AC Commercial power Lm Trunk line Lc Shared branch circuit SW Operation switch

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H02N 6/00 H02N 6/00 (72) Inventor Hirotada Higashihama 1048 Ojidoma, Kadoma-shi, Osaka Inventor Hiroaki Yuasa 1048 Kadoma, Kazuma, Kadoma, Osaka Pref., Matsushita Electric Works, Ltd. (72) Inventor Hiroyuki Ohno 1048 Kadoma, Kazuma, Kadoma, Osaka Pref. Matsushita Electric Works Co., Ltd. 1048, Matsushita Electric Works Co., Ltd. (72) Inventor Hisumi Usui, Kazuma Usui, 1048 Kazumasa Kadoma, Kadoma, Osaka Prefecture, Japan Within a stock company

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 interconnection protection device that separates the power supply from the power converter and stops the power supply to the common branch circuit, and an operation switch that manually restarts the power supply from the power converter to the common branch circuit when the power system is separated A solar power generation system comprising: 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. A box including a disconnecting switch, a power converter, and a system interconnection protection device, wherein an operation unit including an operation switch is provided separately from the box. Item 4. The solar power generation system according to Item 1. 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.