JPH10201105A - Photovoltaic power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit operation control information without laying an exclusive use signal line respectively between a control device and each dispersed power source, in the case of operating a stationary type power converter device of a plurality of solar battery constitutional dispersed power sources by a common one set of control device. SOLUTION: A common one set of control device 18 and each dispersed power source 19a to 19b is provided with a distribution line carrier communication device 21 which is connected to a power line (distribution line 2') of a system 2 to exchange operation control information of a power converter device (inverter 22) of each dispersed power source 19a to 19d between the control device 18 and each dispersed power source 19a to 19d, thereby controlling the power converter device of each dispersed power source 19a to 19d by the control device 18 through the distribution line of the system 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic power generator having a plurality of distributed power sources having a solar cell configuration.

[0002]

2. Description of the Related Art Conventionally, when a photovoltaic power generator is provided as a so-called distributed power source in a factory, a building, a general house, or the like, when a large-scale solar cell with a large power output cannot be installed on a roof or a side wall thereof. Disperses this large-scale solar cell into a plurality of small-sized and small-sized solar cells, and combines these small-sized solar cells with a small-sized and small-capacity inverter as a stationary power converter. A plurality of distributed power sources having a configuration are distributed and installed on the roof and the side wall.

[0003] A conventional photovoltaic power generator comprising a plurality of distributed power sources is formed substantially as shown in FIG.

FIG. 1 shows a case where four distributed power sources 3a, 3b, 3c and 3d are connected to a system 2 on the load side of a power receiving panel 1, and each of the distributed power sources 3a to 3d is, for example, a number. The output of a relatively small and small solar cell 4 of about KW is supplied to, for example, a voltage-type inverter 5 as a static power converter.

Further, the inverters 5 of the distributed power sources 3a to 3d are connected to respective control devices (system controllers) 6
The DC output power of the solar cell 4 is converted into AC power of a system frequency, respectively, and the AC power is transmitted to each of the systems 2 via the respective wiring breakers 7 and load switching boards 8. Power is supplied to the general load 9 and the emergency load 10.

When the system power supply 11 is normal,
By the interconnection operation control of the control device 6 based on the monitoring of the system voltage on the output side of the inverter 5, each of the distributed power sources 3 a to 3 d is individually operated for interconnection with the system power supply 11 based on the output of each solar cell 4. You.

At this time, in order to suppress an increase in the interconnection point voltage of the system 2 due to an increase in the amount of power generation, each of the distributed power sources 3a to 3d
Has a phase leading operation function of the inverter 5 and the interconnection point voltage is 1
When the voltage rises from 05% to 110% or more, each of the inverters 5 is operated in the leading phase according to the amount of the rise.

Next, the system power supply 11 for the occurrence of a disaster, etc.
In order to prevent the adverse effects of the asynchronous operation of the distributed power supplies 3a to 3d when the power failure occurs, only one of the preset distributed power supplies 3a to 3d, for example, only the distributed power supply 3a shifts to the autonomous operation, and the remaining The operation of each of the distributed power sources 3b to 3d is stopped.

Further, the distributed power supply 3a which has shifted to the independent operation
In order to supply the output to the emergency load 10, the control device 6 switches the load switch 8, and supplies the self-sustained operation output of the inverter 5 only to the emergency load 10 via the switch 8.

In FIG. 3, reference numeral 12 denotes an AC breaker of the power receiving panel 1, and 13 denotes a wiring breaker of each load feeder of the system 2.
Reference numeral 4 denotes each switch forming the load switching board 8.

Reference numeral 15 denotes a system interconnection protection relay,
Zero phase transformer (ZPD) 16 for system voltage and capacitor division
Based on this output, an abnormality such as an overvoltage, an undervoltage, or a ground fault of the interconnection point voltage is detected, and the required breaker 12 is opened.

Further, the photovoltaic power generator of FIG. 3 includes a distributed power source 3a and a battery power source 17 having a secondary battery configuration.

The battery power source 17 is connected to the distributed power source 3a which is operated independently. When the distributed power source 3a is operated independently, the input of the inverter 5 is controlled by the control device 6 from the single output of the solar cell 4 to the solar cell 4a. And the battery power supply 17 is switched to a parallel output, and the DC input of the inverter 5 is supplemented by the battery power supply 17.

[0014]

In the case of the above-mentioned conventional solar power generation apparatus, the operation of the inverters 5 of the distributed power supplies 3a to 3d is individually controlled by the respective control devices 6, so that each of the distributed power supplies 3a to 3d is controlled. Requires a control device 6,
The power generator becomes larger.

Further, since the operation of the inverters 5 of the respective distributed power sources 3a to 3d is controlled independently by the respective control devices 6, the following problems are caused.

First, in the interconnection operation, when an increase in the interconnection point voltage due to an increase in the amount of power generation is suppressed by the phase-advanced operation of the distributed power sources 3a to 3d, the reference voltage for the inhibition determination performed by each control device 6 is described. Varies with the distributed power sources 3a to 3d,
The phase operation amounts of the distributed power sources 3a to 3d vary, and in an extreme case, only the distributed power source with the lowest reference voltage is operated in the advanced phase.

In general, the phase-advance operation is clipped at a power factor of 0.85.
If the interconnection point voltage continues to rise even after the power failure, the output (power generation output) may be reduced by actually narrowing down the output. The efficiency deteriorates (decreases).

Next, the proper operation is continued even when the output of the inverter 5 and the load capacity are balanced during the interconnection operation and each of the distributed power sources 3a to 3d is in an independent operation state.
If an attempt is made to detect islanding with the reactive power system widely used for the detection of the active mode of islanding, this detection periodically repeats the variation of the reactive power and changes in the interconnection point voltage etc. Since the shift to the islanding operation is detected, this detection is performed separately and independently in a state where the distributed power sources 3a to 3d are asynchronous, so that the effect of the variable reactive power is offset between the distributed power sources 3a to 3d. This makes detection difficult, and in some cases, a transition to islanding operation cannot be detected.

Further, there is another problem that the operation state of each of the distributed power sources 3a to 3d cannot be monitored centrally at one place, and efficient operation management and the like cannot be performed.

Therefore, each of the distributed power sources 3a to 3d is connected to a common 1
It is conceivable that the above-mentioned points are eliminated by controlling the operation of the two control devices and sharing the reference voltage for the suppression determination.

In this case, transmission of operation control information between one common control device and each of the distributed power sources 3a to 3d is generally performed as follows.
A dedicated signal line (cable) is laid between the control device and each of the distributed power supplies 3a to 3d, and a wired communication method using a dedicated line is performed.

However, when this dedicated wire communication system is adopted, communication work such as laying of each signal line, which is complicated and requires labor, time and cost, is required. In this case, as the number of distributed power sources increases, the number of distributed power sources increases. As the length of the signal line increases, the number of signal lines increases. In this case, there is a problem that the signal line becomes more complicated and requires labor, time and cost.

If each signal line is formed by an optical fiber in order to eliminate the influence of disturbance (noise), it becomes extremely expensive.

According to the present invention, a dedicated signal line is provided between the control device and each of the distributed power sources when the operation of the power converters of the plurality of distributed power sources having the solar cell configuration is controlled by one common control device. It is an object to enable operation control information to be transmitted without laying.

[0025]

In order to solve the above-mentioned problems, in a photovoltaic power generator according to the present invention, one common control device and each distributed power source are connected to a system power line and connected to a control device. A distribution line carrier communication device for exchanging operation control information of the power conversion device between the power supply device and each distributed power source is provided, and the control device controls the power conversion device of each distributed power source via a system distribution line.

Therefore, the communication of the operation control information of the power conversion device between the common control device and each distributed power source is performed by the distribution line conveyance using the power line of the system without laying a dedicated signal line. .

Further, in the photovoltaic power generator of the present invention, wireless communication for exchanging operation control information of the power conversion device between the control device and each distributed power source to one common control device and each distributed power source. A device is provided, and the control device controls the power conversion device of each distributed power supply by wireless communication.

Therefore, in this case, the communication of the operation control information of the power converter between the common control device and each distributed power source is performed by wireless communication without laying a dedicated signal line.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. (First Embodiment) First, a first embodiment of the present invention corresponding to the photovoltaic power generator of claim 1 will be described with reference to FIG. FIG. 1 shows one common control device (main controller) 18 having an address # 0 and addresses # 1 and #
4, # 3, # 4, four distributed power supplies (AC array) 19
1A, 19B, 19C and 19D are single-line system diagrams in a case where a battery power supply (battery panel) 20 is provided.

In FIG. 1, the same reference numerals as those in FIG. 3 denote the same or corresponding elements, and the difference between the configuration of FIG. 1 and the conventional configuration of FIG. 3 is mainly the following points (i) to (iv). It is.

(I) Each of the distributed power supplies 19a to 19d is not provided with a separate control device 6 for the conventional power supplies 3a to 3d in FIG.
Centrally controlled by one common control device 18 provided at a factory, a building management office, or the like.

(Ii) The controller 18 and each distributed power supply 19a
To 19d, the distribution line carrier communication device 21 connected to the distribution line 2 ′ as the power line of the system 2 is provided.

(Iii) Instead of the inverters 5 of the conventional power supplies 3a to 3d shown in FIG.
In that a voltage-type inverter 22 having a function of switching to a parallel input of the output of the battery power supply 20 and a charge converter function of the battery power supply 20 is provided. The battery power supply 20 forms a common auxiliary DC power supply for each of the distributed power supplies 19a to 19d.

(Iv) Instead of the grid connection protection relay 15 of FIG. 5, a grid connection protection relay 23 having a configuration in which, for example, a wired communication function is added to the relay 15 is provided. A signal of detection information such as overvoltage and undervoltage of the relay 23 is transmitted to the operation control unit 24 of the microcomputer configuration of the control device 18, and each of the distributed power supplies 19 a to 19 is utilized by using the detection information of the system interconnection protection relay 23.
The point that d is protected from interconnection.

Then, the controller 18 and each distributed power source 19a
-19d to exchange operation control information of the inverter 22 of each of the distributed power supplies 19a-19d by distribution line transport communication via the distribution line 2 ', the respective distribution line transport communication devices 21 And a demodulator 21b for reception.

Next, the control device 18 will be described.
The control device 18 is supplied with the detection information of the system interconnection protection relay 23, and the system voltage of the distribution line 2 'is supplied as information of the synchronization voltage (interconnection point voltage) via the instrument transformer 25.

The selection of the manual or automatic operation mode selectively switches to the control of the individual interconnection operation mode, the parallel independent operation mode, and the charging operation mode. During the interconnection operation, each of the distributed power supplies 19a to 19d is switched. Independent operation is controlled individually, and in the independent operation, the distributed power sources 19a to 19d are synchronized to be controlled to the parallel independent operation. In the charging operation, the distributed power sources 19a to 1d are controlled.
Control is performed to charge the battery power supply 20 by the 9d converter operation.

That is, when the operation mode is selected, the operation control unit 24 executes a preset program for each operation mode.

At this time, the information of the synchronization voltage from the instrument transformer 25 is divided and processed into a synchronization control timing signal (synchronization signal) at the time of interconnection operation, and the size of the information is divided into various values. This is a common criterion for starting the operation of the power supplies 19a to 19d (starting the phase advance operation).

During self-sustained operation or the like in which information on the synchronization voltage is not obtained, a timing signal for synchronization control of the system frequency is formed by the free-running oscillation output of the control device 18 at the reference frequency.

Then, the operation control unit 24 determines the timing signal, the detection information of the system interconnection protection relay 23, the synchronous voltage of the instrument transformer 25, and the current operation state and power generation notified from each of the distributed power supplies 19a to 19d. The status and the like of the system power supply 11 and the distributed power supplies 19a to 19d are monitored by a sequence control process based on the output, the output voltage, and the like.

Further, for example, a system interconnection operation protection relay 2
Based on the detection information of No. 3, the presence / absence of a system power outage is detected and information on operation / stop is formed.

That is, based on the monitoring, the operation control unit 24 determines the timing signal, the command signal for starting the early phase operation, the parallel operation / individual operation, the independent operation / interconnection operation, and the power generation operation in accordance with the selected operation mode or the like. / Charging operation, operation /
A signal for operation control information on the control device side, such as a stop mode change signal and a data request signal, is formed.

Further, these operation control information signals are:
In order to individually or simultaneously transmit to the distributed power supplies 19a to 19d in a predetermined communication format, the address # 0 (transmission source address) of the control device 18 and the distributed power supplies 19a to 19d are transmitted.
The individual address # 1 to # 4 of d or a common address (destination address) and the like are added and processed into a downlink transmission signal.

The downstream transmission signal is sent from the operation control unit 24 to the transmitter 21a of the distribution line carrier communication device 21, and the downstream transmission signal is converted by the transmitter 21a to an appropriate frequency which is less affected by the system frequency. Modulated distribution line 2 '
Sent to

Further, an upstream transmission signal, which will be described later, transmitted from each of the distributed power supplies 19a to 19d to the distribution line 2 'in accordance with the data request signal is received and demodulated by the demodulator 21b of the control device 18, and this demodulation causes Distributed power supply 19a-
Operation control information such as the current operation state, power generation output, and output voltage of 19d is reproduced.

Then, based on the operation control information from each of the distributed power supplies 19a to 19d, the operation control unit 24
Of the distributed power supplies 19a to 19d are collectively displayed on a display (not shown).

Next, each of the distributed power supplies 19a to 19d will be described. Each of the distributed power supplies 19a to 19d receives and demodulates the downstream transmission signal of the distribution line 2 'by the demodulator 21b of the distribution line carrier communication device 21, and the address # 1 to # 4 of the own device or the common address is used. The added operation control information signal is transmitted from the demodulator 21b to the respective inverters 22.
Transfer to

The inverter 22 changes its operation mode (operation mode) to any one of the above-described individual interconnection operation mode, parallel independent operation mode, and charging operation mode based on the operation mode command given to the operation control information.

Then, during the normal interconnection operation in which the individual interconnection operation mode is commanded, the inverters 22 of the distributed power supplies 19a to 19d individually operate in synchronization with the system voltage based on the received timing signal. .

At this time, based on monitoring of the output voltage and the like of the solar cell 4, the inverter 22 operates so as to take out the maximum electric power of the solar cell 4 so as to extract the maximum electric power from the solar cell 4.

By this inverter operation, each distributed power supply 19
a to 19d are individually operated in synchronization with the system voltage,
The momentary maximum power of each of the solar cells 19a to 19d is converted to AC power of the system frequency.

At this time, since the inverters 22 of the distributed power supplies 19a to 19d are operated in synchronization with the system voltage, the distributed power supplies 19a to 19d are operated in synchronization with each other.

When the interconnection point voltage tends to increase, an instruction to start the phase advance operation is received during the individual interconnection operation in order to suppress the excessive increase, and the inverter 22 of each of the distributed power supplies 19a to 19d operates. The phase is driven.

At this time, each of the distributed power supplies 19a to 19d is operated in accordance with a common voltage of the same determination criterion based on a command for starting the phase operation from the control device 18, and the conventional distributed power supply is used. The dispersion of the advanced operation amount between 19a to 19d is prevented, and the dispersed power supplies 19a to 19d are uniformly operated in advanced phase. The overall power generation efficiency is prevented from lowering and the interconnection point voltage is suppressed.

Further, based on a timing signal synchronized with the system voltage, the inverter 2 of each of the distributed power supplies 19a to 19d
Numeral 2 varies the reactive power of its output by synchronizing the disturbance occurrence timing, and monitors and detects the transition to the isolated operation state by a so-called reactive power fluctuation method.

Therefore, the effect of varying the reactive power of each of the distributed power supplies 19a to 19d is not canceled among the distributed power supplies 19a to 19d, and even if each of the distributed power supplies 19a to 19d is in the independent operation state, this state is ensured. The operation is detected and the operation is continued.

Next, at the time of parallel independent operation in which a system blackout or the like occurs and the parallel independent operation mode is instructed, each distributed power source 1
The inverters 9a to 19d switch to the inverter operation of the self-sustained operation. At this time, the inverters 22 of the distributed power supplies 19a to 19d are operated in synchronization based on the timing signal of the free-running oscillation of the control device 18.

The input power of each of the distributed power supplies 19a to 19d is a parallel power supply of the solar cell 4 and the battery power supply 20.

Therefore, when a power outage occurs due to a disaster or the like, all the inverters 22 of the distributed power supplies 19a to 19d operate independently in synchronization with each other, and the distributed power supplies 19a to
The power that can be supplied to the emergency load 10 is greater than when one of the 19d is operated, and the emergency load 10 can be made sufficiently large.

In addition, by using the battery power supply 20 together, it is possible to ensure stable power supply during the self-sustained operation and further increase the power supply.

Next, when the charge operation mode is commanded,
The inverter 22 of each of the distributed power supplies 19a to 19d switches to the converter operation, and the battery power supply 20 is charged by the converter output of each of the distributed power supplies 19a to 19d.

In this case, the battery power supply 20 is charged with a larger amount of charging power than when the charging is performed by using the converter output of any one of the distributed power supplies 19a to 19d without separately preparing a large dedicated charging facility or the like. Thus, the capacity of the battery power supply 20 can be increased.

By the way, the operation state, the amount of power generation, and the output voltage of each of the distributed power supplies 19a to 19d are
And this monitoring information forms operation control information on the distributed power source side.

When each of the distributed power supplies 19a to 19d receives the data request signal from the control device 18, the address # 1 of each of the distributed power supplies 19a to 19d is added to the operation control information signal on the distributed power supply side of each inverter 22. # 4 (source address), address # 0 (destination address) of the control device 18 and the like are added to form an upstream transmission signal, and this upstream transmission signal is transmitted to the transmitter 21 of the distributed power supplies 19a to 19d.
By a, the signal is modulated in the same manner as the downstream transmission signal and transmitted to the distribution line.

Therefore, in the case of FIG.
By controlling the operation of each of the distributed power supplies 19a to 19d by one common control apparatus 18 by communication of distribution line conveyance using a transmission path of operation control information between the control device 18 and each of the distributed power supplies 19a to 19d, The inconvenience when each of the distributed power supplies 19a to 19d is individually operated by each control can be eliminated.

Then, the controller 18 and each distributed power source 19a
It is not necessary to lay a dedicated signal line for the operation control information between the device and the device, and no signal line (communication cable) is required for the signal line and the laying work is not required. be able to.

The control device 18 and each of the distributed power sources 19a to 19a
It goes without saying that various systems such as a polling communication system for calling each of the distributed power supplies 19a to 19d from the control device 18 can be adopted as a communication system between the control device 18 and the communication device 19d.

The control device 18 and each distributed power source 19a
The transmission / reception frequency (frequency band) to 19d, modulation method, etc.
Depending on the communication method or the like, the setting may be the same or different for each device or different for each of the upstream and downstream.

(Second Embodiment) Next, a second embodiment of the present invention corresponding to the photovoltaic power generator of claim 2 will be described with reference to FIG. 2, the same reference numerals as those in FIG. 1 denote the same or corresponding components.

In FIG. 2, the control device 18 and each of the distributed power supplies 19a to 19d are provided with a modulation / demodulation converter 26a, a radio transmitter 26b, and a receiver 26c instead of the distribution line carrier communication device 21 of FIG. Wireless communication device 26 comprising
Is provided.

In this case, the signal of the downstream operation control information of the control device 18 and the signal of the upstream operation control information of each of the distributed power supplies 19a to 19d are modulated by the respective converters 26a and transmitted wirelessly from the transmitter 26b. You.

The signals transmitted by radio are received by the distributed power supplies 19a to 19d and the receiver 26c of the control device 18 and demodulated by the respective converters 26a.

Therefore, in FIG. 2, the operation information is transmitted between the control device 18 and each of the distributed power sources 19a to 19d by wireless communication. In this case, the same effect as in the case of FIG. 1 is obtained. Can be

Moreover, the influence of the system power as in the case of the distribution line transport system is small, there is no restriction on the transmission / reception frequency, the degree of freedom in design and the like is greater than in the case of FIG. 1, and the reliability of communication is improved.

The radio signal may be modulated by various methods such as AM, FM, and FSK.

By the way, the number of distributed power sources and the like may be any. Further, each distributed power source may not be provided in a building, and may be provided in place of, for example, a soundproof wall of a railway such as an expressway or a bullet train.

Furthermore, the stationary power converters of the distributed power supplies 19a to 19d may have a power converter configuration other than the inverter.

Next, in both of the above embodiments, communication between the control device 18 and a part of the distributed power source, for example, the distributed power source 19a, or the control device 18 and the distributed power sources 19a to 19d
The communication of the main part of the information between them may be secured by wired communication such as an optical fiber to further improve the reliability.

[0080]

The present invention has the following effects. First, in the case of claim 1, one common control device 1
8 and each distributed power supply 19 between the distributed power supplies 19a to 19d.
The communication of the operation control information of the power converters (inverter 22) of a to 19d can be performed by the distribution line conveyance using the power line (distribution line 2 ′) of the system 2 without laying a dedicated signal line, A common control device for each of the distributed power supplies 19a to 19d can be used, and communication work can be reduced, thereby greatly reducing labor and cost.

Furthermore, the common use of the control device eliminates the inconvenience of providing the control device individually for each of the distributed power supplies 19a to 19d, thereby improving the performance and improving the reliability.

Next, in the case of claim 2, the wireless communication device 2 is connected to the common control device 18 and each of the distributed power sources 19a to 19d.
6, the control device 18 and each of the distributed power sources 19a to 19a-1
Communication of the operation control information of the power converter (inverter 22) of each of the distributed power supplies 19a to 19d with the power supply 9d can be performed by wireless communication without laying a dedicated signal line.

In this case, the same effect as that of the first aspect can be obtained, and there is also an advantage that there is almost no restriction on the communication conditions due to the influence of the system 2 and the degree of freedom in design is increased.

[Brief description of the drawings]

FIG. 1 is a connection diagram of a first embodiment of the present invention.

FIG. 2 is a connection diagram of a second embodiment of the present invention.

FIG. 3 is a connection diagram of a conventional example.

[Explanation of symbols]

 2 system 2 'distribution line 18 controller 19a to 19d distributed power supply 21 distribution line carrier communication device 22 inverter 26 wireless communication device

Claims (2)

[Claims] An operation of a stationary power converter of a plurality of distributed power supplies connected to a system is controlled by a common controller, and an output of a solar cell of each of the distributed power supplies is converted into AC power. A photovoltaic power generator that supplies power to a system load by connecting the control device and each of the distributed power sources to a power line of a system and transmitting operation control information of the power conversion device between the control device and each of the distributed power sources. A photovoltaic power generator, comprising: a distribution line carrier communication device for communication, wherein the control device controls the power converters of the respective distributed power sources via the distribution line of the system. 2. The operation of a stationary power converter of a plurality of distributed power supplies connected to a grid is controlled by a common controller, and the output of a solar cell of each of the distributed power supplies is converted into AC power. A photovoltaic power generator that feeds power to a system load by providing a wireless communication device for exchanging operation control information of the power conversion device between the control device and each of the distributed power sources. The solar power generation device, wherein the control device controls the power conversion devices of the respective distributed power sources by wireless communication.