Power Conversion System for Distributed Power Sources

Abstract

Provided is a power conversion system for a dispersed power source, wherein a conductivity test of a power converter can be performed prior to power reception in a system. This power conversion system for a dispersed power source comprises: a plurality of power converters that convert DC power into AC power; and a control device that selects at least one power converter among the plurality of power converters as a power converter under test, and performs a conductivity test of the power converter under test in a condition in which the AC side of the power converter under test is not connected to a system but is connected to an AC power source device and a load bank, and a voltage on the AC side of the power converter under test has been established.

Description

[Technical field]

[0001] The present invention relates to a power conversion system for a distributed power source. [Background technology]

[0002] Patent Document 1 discloses a power conversion system for distributed power sources. According to this power conversion system for distributed power sources, when a plurality of power conversion devices are operated by a single common control device, operation control information can be transmitted without laying a dedicated signal line. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 10-201105 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the power conversion system for distributed power sources described in Patent Document 1, a current test of the power converter is performed after the system starts receiving power. Therefore, if it takes time to prepare the power receiving equipment on the system side, the current test of the power converter cannot be performed. As a result, the start of power sales is delayed.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a power conversion system for distributed power sources that can perform a current test of a power converter before receiving power from a grid. [Means for solving the problem]

[0006] The present invention relates to a power conversion system for a distributed power source, comprising: a power grid switch; The AC side A switch is connected in parallel with the grid switch. DC side Multiple solar power generation facilities and Connected in seriesThe power conversion system includes a plurality of power conversion units and a control device that controls the plurality of power conversion units. Each power conversion unit includes a power converter that converts DC power into AC power, a DC switch provided on the DC side of the power converter, and an AC switch provided on the AC side of the power converter. The control device controls at least one of the power converters when the grid switch is in a cutoff state. but Selected as the power converter under test Be , a DC switch corresponding to the power converter under test but Connected status Be Other DC switches but In a blocked state Be , an AC switch corresponding to the power converter under test but Connected status Be Other AC switches but In a blocked state Be An AC power supply device and a load bank are temporarily connected to the AC side of the test power converter, and the test power converter is controlled during a current test of the test power converter while a voltage on the AC side of the test power converter is established.

[0007] The present invention relates to a power conversion system for a distributed power source, comprising: a power grid switch; The AC side A switch is connected in parallel with the grid switch. DC side Multiple solar power generation facilities and Connected in series The power conversion system includes a plurality of power conversion units and a control device that controls the plurality of power conversion units. Each power conversion unit includes a power converter that converts DC power to AC power or converts AC power to DC power, a DC switch provided on the DC side of the power converter, and an AC switch provided on the AC side of the power converter. The control device controls at least one of the power converters when the grid switch is in a cutoff state. but Selected as a power converter to maintain AC voltage Be a power converter different from the power converter for maintaining the AC voltage; but Selected as the power converter under test Be A DC switch corresponding to the power converter for maintaining the AC voltage but Connected status Be Other DC switches butIn a blocked state Be A power converter for maintaining the AC voltage and an AC switch corresponding to the power converter under test but Connected status Be Other AC switches but In a blocked state Be A DC side between the power converter for maintaining the AC voltage and the power converter under test but Temporarily connect to make it a common state Be During a current test of the test power converter, the power converter for maintaining the AC voltage is controlled so that the voltage on the AC side of the power converter for maintaining the AC voltage is constant.

[0008] The present invention relates to a power conversion system for a distributed power source, comprising: a power grid switch; The AC side A switch is connected in parallel with the grid switch. DC side Multiple DC power sources Connected in series The power conversion system includes a plurality of power conversion units and a control device that controls the plurality of power conversion units. Each power conversion unit includes a power converter that converts DC power to AC power or converts AC power to DC power, a DC switch provided on the DC side of the power converter, and an AC switch provided on the AC side of the power converter. One of the multiple DC power sources is a power storage facility and the others are solar power generation facilities. The control device ,before When the system switch is in an interrupted state, one power converter connected to the storage facility but Selected as a power converter to maintain AC voltage Be a power converter different from the power converter for maintaining the AC voltage; but Selected as the power converter under test Be A power converter for maintaining the AC voltage and a DC switch corresponding to the power converter under test but Connected status Be Other DC switches but In a blocked state Be A power converter for maintaining the AC voltage and an AC switch corresponding to the power converter under test but Connected status Be Other AC switches but In a blocked state By beingThe AC sides of the power converter for maintaining the AC voltage and the test power converter are temporarily connected to each other, and during a current test of the test power converter, the power converter for maintaining the AC voltage is controlled so that the voltage on the AC side of the power converter for maintaining the AC voltage is constant.

[0009] The present invention relates to a power conversion system for a distributed power source, comprising: a power grid switch; The AC side A switch is connected in parallel with the grid switch. DC side Multiple solar power generation facilities and Connected in series The power conversion system includes a plurality of power conversion units and a control device that controls the plurality of power conversion units. Each power conversion unit includes a power converter that converts DC power to AC power or converts AC power to DC power, a DC switch provided on the DC side of the power converter, and an AC switch provided on the AC side of the power converter. The control device controls at least one of the power converters when the grid switch is in a cutoff state. but Selected as a power converter for regeneration Be a power converter different from the power converter for regeneration; but Selected as the power converter under test Be A DC switch corresponding to the regenerative power converter but Connected status Be Other DC switches but In a blocked state Be An AC switch corresponding to the regenerative power converter and the test power converter but Connected status Be Other AC switches but In a blocked state By being The AC sides of the regenerative power converter and the test power converter are temporarily connected to each other and to an AC power supply device, and in a state in which a voltage on the AC side of the test power converter is established by the AC power supply device, but Temporarily connect to make it a common state Be During an energization test of the test power converter, the regenerative operation of the regenerative power converter is controlled so that the power generated by the test power converter is regenerated to the DC side. Effect of the Invention

[0010] According to these inventions, a current test of the power converter can be performed before receiving power from the grid. [Brief description of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of a power system to which a distributed power supply power conversion system in a first embodiment is applied. [Diagram 2] 2 is a hardware configuration diagram of a control device of the distributed power source power conversion system in the first embodiment. FIG. [Diagram 3] FIG. 11 is a configuration diagram of a power system to which a distributed power supply power conversion system in a second embodiment is applied. [Figure 4] FIG. 11 is a configuration diagram of a power system to which a distributed power supply power conversion system in a third embodiment is applied. [Diagram 5] FIG. 11 is a configuration diagram of a power system to which a distributed power source power conversion system in a fourth embodiment is applied. [Figure 6] FIG. 13 is a configuration diagram of a power system to which a distributed power supply power conversion system in a fifth embodiment is applied. [Figure 7] FIG. 13 is a configuration diagram of a power system to which a distributed power source power conversion system in a sixth embodiment is applied. [Figure 8] FIG. 13 is a configuration diagram of a power system to which a distributed power source power conversion system in a seventh embodiment is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals. The description of the same parts will be appropriately simplified or omitted.

[0013] Embodiment 1 FIG. 1 is a configuration diagram of a power system to which a distributed power supply power conversion system according to a first embodiment is applied.

[0014] In the power system of Fig. 1, a plurality of photovoltaic power generation facilities 1 are, for example, solar cells, and are installed outdoors. Four photovoltaic power generation facilities 1 are illustrated in Fig. 1. A power grid 2 is operated by a power company or the like. A distributed power source power conversion system 3 is connected between the plurality of photovoltaic power generation facilities 1 and the power grid 2.

[0015] The distributed power source power conversion system 3 includes a plurality of power converters 4, a plurality of DC side switches 5, a plurality of transformers 6, a plurality of AC side switches 7, a system side switch 8, and a control device 9.

[0016] An input portion of each of the multiple power converters 4 is connected to an output portion of each of the multiple photovoltaic power generation facilities 1. Each of the multiple power converters 4 is provided so as to be able to convert DC power from each of the multiple photovoltaic power generation facilities into AC power.

[0017] Each of the multiple DC side switches 5 is connected between each of the multiple photovoltaic power generation facilities 1 and each of the multiple power converters 4. Each of the multiple DC side switches 5 is, for example, a circuit breaker, and is provided so as to be able to cut off the connection between each of the multiple photovoltaic power generation facilities 1 and each of the multiple power converters 4 when an overcurrent occurs between each of the multiple photovoltaic power generation facilities 1 and each of the multiple power converters 4.

[0018] Each of the multiple transformers 6 is connected between each of the multiple power converters 4 and the grid 2. Each of the multiple transformers 6 is provided so as to be able to transform the AC voltage from each of the multiple power converters 4.

[0019] Each of the multiple AC side switches 7 is connected between each of the multiple power converters 4 and each of the multiple transformers 6. Each of the multiple AC side switches 7 is, for example, a circuit breaker, and is provided so as to be able to cut off the connection between each of the multiple power converters 4 and each of the multiple transformers 6 when an overcurrent occurs between each of the multiple power converters 4 and each of the multiple transformers 6.

[0020] The system-side switch 8 is provided between the multiple transformers 6 and the system 2. The system-side switch 8 is, for example, a circuit breaker, and is provided so as to be able to cut off the connection between the multiple transformers 6 and the system 2 when an overcurrent occurs between the multiple transformers 6 and the system 2.

[0021] The control device 9 is provided so as to be able to control the multiple power converters 4. Each of the multiple power converters 4 may be provided with an independent control device 9.

[0022] In the distributed power conversion system 3, a commissioning test is performed before receiving power from the grid 2. Specifically, in a state in which the grid-side switch 8 cuts off the connection between the multiple transformers 6 and the grid 2, at least one power converter 4 out of the multiple power converters 4 is selected as a power converter 4 under test.

[0023] The AC side switch 7 corresponding to the test power converter 4 is maintained in a state in which the test power converter 4 is connected to the transformer 6. The other AC side switches 7 are maintained in a state in which the connection between the power converter 4 and the switch is cut off.

[0024] In this state, an AC power supply device 10 and a load bank 11 are temporarily connected to the output side of a transformer 6 corresponding to the power converter 4 under test.

[0025] The DC side switch 5 corresponding to the test power converter 4 is maintained in a state in which the connection between the photovoltaic power generation facility 1 and the test power converter 4 is established. The other DC side switches 5 are maintained in a state in which the connection between the photovoltaic power generation facility 1 and the power converter 4 is interrupted.

[0026] In this state, the AC power supply device 10 establishes the voltage on the AC side of the power converter 4 under test, and then the control device 9 operates the power converter 4 under test, thereby carrying out an electrical test.

[0027] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0028] According to the first embodiment described above, the AC side of the test power converter 4 is not connected to the system 2 but is connected to the AC power supply device 10 and the load bank 11, and a current test is performed on the test power converter 4 in a state in which the voltage on the AC side of the test power converter 4 is established. The active power injected on the AC side is absorbed by the load bank 11. Therefore, the test power converter 4 can be caused to output active power. As a result, a current test on the power converter 4 can be performed before receiving power from the system 2.

[0029] The AC power supply device 10 may be a generator, an AC power supply, a motor generator, a power converter, or the like.

[0030] The output power of the power converter 4 under test is consumed in the load bank 11. Therefore, the AC power supply device 10 only needs to output reactive power for maintaining the AC voltage, and the rated power may be smaller than that of the power converter 4 under test.

[0031] Next, an example of the control device 9 will be described with reference to FIG. FIG. 2 is a hardware configuration diagram of the control device of the distributed power source power conversion system in the first embodiment.

[0032] Each function of the control device 9 may be realized by a processing circuit. For example, the processing circuit includes at least one processor 100a and at least one memory 100b. For example, the processing circuit includes at least one dedicated hardware 200.

[0033] When the processing circuit includes at least one processor 100a and at least one memory 100b, each function of the control device 9 is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. At least one of the software and firmware is stored in the at least one memory 100b. The at least one processor 100a realizes each function of the control device 9 by reading and executing the program stored in the at least one memory 100b. The at least one processor 100a is also called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. For example, the at least one memory 100b is a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD, or the like.

[0034] When the processing circuit includes at least one dedicated hardware 200, the processing circuit is realized, for example, by a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. For example, each function of the control device 9 is realized by a processing circuit. For example, each function of the control device 9 is realized collectively by a processing circuit.

[0035] Some of the functions of the control device 9 may be realized by dedicated hardware 200, and the remaining parts may be realized by software or firmware. For example, the function of controlling the power converter 4 under test may be realized by a processing circuit as the dedicated hardware 200. , supply Functions other than the function of controlling the power converter 4 may be realized by at least one processor 100a reading and executing a program stored in at least one memory 100b.

[0036] Thus, the processing circuitry implements each function of the controller 9 in hardware 200, software, firmware, or a combination thereof.

[0037] Embodiment 2 3 is a configuration diagram of a power system to which a distributed power conversion system according to embodiment 2 is applied. Note that parts that are the same as or correspond to parts according to embodiment 1 are given the same reference numerals. Explanation of these parts will be omitted.

[0038] In a commissioning test of the distributed power conversion system 3 of the second embodiment, in a state in which the system-side switch 8 cuts off the connection between the multiple transformers 6 and the system 2, at least one power converter 4 out of the multiple power converters 4 is selected as a power converter 4 for maintaining an AC voltage. Among the multiple power converters 4, a power converter 4 other than the power converter 4 for maintaining an AC voltage is selected as a power converter 4 under test.

[0039] The AC side switch 7 corresponding to the power converter 4 for maintaining the AC voltage is maintained in a state in which the connection between the power converter 4 for maintaining the AC voltage and the transformer 6 is established. The AC side switch 7 corresponding to the test power converter 4 is maintained in a state in which the connection between the test power converter 4 and the transformer 6 is established. The other AC side switches 7 are maintained in a state in which the connection between the power converter 4 and the transformer 6 is interrupted.

[0040] In this state, a load bank 11 is temporarily connected to the output sides of a transformer 6 corresponding to a power converter 4 for maintaining an AC voltage and a transformer 6 corresponding to a power converter 4 under test.

[0041] The DC side switch 5 corresponding to the power converter 4 for maintaining the AC voltage is maintained in a state in which the connection between the photovoltaic power generation equipment 1 and the power converter 4 for maintaining the voltage is interrupted. The DC side switch 5 corresponding to the test power converter 4 is maintained in a state in which the connection between the photovoltaic power generation equipment 1 and the test power converter 4 is established. The other DC side switches 5 are maintained in a state in which the connection between the photovoltaic power generation equipment 1 and the power converter 4 is interrupted.

[0042] In this state, the control device 9 performs a current test on the power converter 4 under test while controlling the power converter 4 for maintaining the AC voltage so that the voltage on the AC side of the power converter 4 for maintaining the AC voltage is constant. The power converter 4 for maintaining the AC voltage outputs reactive power to control the voltage on the AC side.

[0043] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0044] According to the second embodiment described above, in a state in which the AC sides of the voltage maintaining power converter 4 and the test power converter 4 are connected to the load bank 11, the power converter 4 for maintaining AC voltage is controlled so that the voltage on the AC side of the power converter 4 for maintaining voltage is constant during an energization test of the test power converter 4. In addition, the active power injected into the AC side is consumed by the load bank 11. Therefore, it is possible to cause the test power converter 4 to output active power. Therefore, an energization test of the power converter 4 can be performed without requiring the AC power supply device 10 before receiving power from the system 2.

[0045] In the second embodiment, it is sufficient that at least two power converters 4 are provided with an independent operation function or an AVR mode function. A power converter 4 with an independent operation function is expensive due to the need for certification and the like. For this reason, if a power converter 4 with an AVR mode function is used, the energization test of the power converter 4 can be performed inexpensively.

[0046] Embodiment 3 4 is a configuration diagram of a power system to which a distributed power conversion system according to embodiment 3 is applied. Note that parts that are the same as or correspond to parts according to embodiment 2 are given the same reference numerals. Explanation of these parts is omitted.

[0047] In a commissioning test of the distributed power conversion system 3 of the third embodiment, the AC-side switch 7 corresponding to the power converter 4 for maintaining the AC voltage is maintained in a state in which the connection between the power converter 4 for maintaining the AC voltage and the transformer 6 is established. The AC-side switch 7 corresponding to the power converter 4 under test is maintained in a state in which the connection between the power converter 4 under test and the transformer 6 is established.

[0048] In this state, the DC sides of the power converter 4 for maintaining the AC voltage and the power converter 4 under test are temporarily connected via the test cable 12 .

[0049] The DC side switch 5 corresponding to the power converter 4 for maintaining the AC voltage is maintained in a state in which the connection between the photovoltaic power generation facility 1 and the power converter 4 for maintaining the AC voltage is established. The DC side switch 5 corresponding to the test power converter 4 is maintained in a state in which the connection between the photovoltaic power generation facility 1 and the test power converter 4 is interrupted.

[0050] In this state, the control device 9 performs a current test on the power converter 4 under test while controlling the power converter 4 for maintaining the AC voltage so that the voltage on the AC side of the power converter 4 for maintaining the AC voltage is constant.

[0051] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0052] According to the above-described third embodiment, in a state in which the DC sides of the power converter 4 under test and the power converter 4 for maintaining the AC voltage are shared, the power converter 4 for maintaining the AC voltage is controlled so that the voltage on the AC side of the power converter 4 for maintaining the AC voltage is constant during an energization test of the power converter 4 under test. In addition, the AC power generated by the power converter 4 under test is converted to DC power by the power converter 4 for maintaining the AC voltage, and is again provided to the DC side of the power converter 4 under test. For this reason, an energization test of the power converter 4 can be performed without requiring the AC power supply device 10 and the load bank 11 before receiving power from the system 2.

[0053] Embodiment 4 5 is a configuration diagram of a power system to which a distributed power conversion system according to embodiment 4 is applied. Note that parts that are the same as or correspond to parts according to embodiment 3 are given the same reference numerals. Explanation of these parts will be omitted.

[0054] In a commissioning test of the power conversion system 3 for distributed power sources in embodiment 4, an AC power supply device 10 is connected to the output side of a transformer 6 corresponding to the regenerative power converter 4 and a transformer 6 corresponding to the power converter 4 under test.

[0055] In this state, the AC power supply device 10 establishes the voltage on the AC side of the test power converter 4, and then the control device 9 performs a current test on the test power converter 4 while performing regenerative operation of the regenerative power converter 4 so as to regenerate the power generated by the test power converter 4 to the DC side.

[0056] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0057] According to the fourth embodiment described above, in a state in which the AC sides of the regenerative power converter 4 and the test power converter 4 are connected to the AC power supply device 10, the regenerative operation of the regenerative power converter 4 is performed during a current test of the test power converter 4. Therefore, a current test of the power converter 4 can be performed by the small-capacity AC power supply device 10 before receiving power from the system 2.

[0058] Embodiment 5. 6 is a configuration diagram of a power system to which a distributed power conversion system according to embodiment 5 is applied. Note that parts that are the same as or equivalent to those in embodiment 4 are given the same reference numerals. Explanation of these parts will be omitted.

[0059] In the commissioning test of the power conversion system 3 for distributed power sources of embodiment 5, the DC side switch 5 corresponding to the power converter 4 for maintaining the DC voltage is maintained in a state in which the connection between the solar power generation equipment 1 and the power converter 4 for maintaining the DC voltage is cut off.

[0060] In this state, the AC power supply device 10 establishes the voltage on the AC side of the test power converter 4, and the control device 9 performs a current test on the test power converter 4 while controlling the power converter 4 for maintaining the DC voltage so that the voltage on the DC side of the power converter 4 for maintaining the DC voltage is constant.

[0061] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0062] According to the fifth embodiment described above, in a state in which the DC sides of the power converter 4 for maintaining a DC voltage and the power converter 4 under test are connected to each other and the AC sides of the power converter 4 for maintaining a DC voltage and the power converter 4 under test are connected to the AC power supply device 10, the power converter 4 for maintaining a DC voltage is controlled so that the voltage on the DC side of the power converter 4 for maintaining a DC voltage is constant during an energization test of the power converter 4 under test. Therefore, even if a connection to a DC power source is not established before receiving power from the system 2, an energization test of the power converter 4 can be performed with the small-capacity AC power supply device 10.

[0063] Embodiment 6 7 is a configuration diagram of a power system to which a distributed power conversion system according to embodiment 6 is applied. Note that parts that are the same as or correspond to parts in embodiment 2 are given the same reference numerals. Explanation of these parts is omitted.

[0064] In a commissioning test of the distributed power conversion system 3 of the sixth embodiment, in a state in which the system-side switch 8 cuts off the connection between the multiple transformers 6 and the system 2, a power converter 4 having a power storage facility 13 connected to the DC side is selected as the power converter 4 for charging. Of the multiple power converters 4, a power converter 4 different from the power converter 4 for charging is selected as the power converter 4 under test.

[0065] The DC side switch 5 corresponding to the charging power converter 4 is maintained in a state in which a connection between the storage equipment 13 and the charging power converter 4 is established. The DC side switch 5 corresponding to the test power converter 4 is maintained in a state in which a connection between the photovoltaic power generation equipment 1 and the test power converter 4 is established.

[0066] An AC power supply device 10 is connected to the output sides of a transformer 6 corresponding to the power converter 4 for charging and a transformer 6 corresponding to the power converter 4 under test.

[0067] In this state, the AC power supply device 10 establishes the voltage on the AC side of the test power converter 4, and then the control device 9 performs a charging operation of the charging power converter 4 so as to charge the power generated by the test power converter 4, while performing a current test of the test power converter 4.

[0068] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0069] The power stored in the power storage facility 13 may be discharged by a discharge resistor provided on the DC side or AC side.

[0070] According to the sixth embodiment described above, in a state in which the AC sides of the charging power converter 4 and the test power converter 4 are connected to the AC power supply device 10, the charging power converter 4 is operated in regenerative mode during a power test of the test power converter 4. Therefore, before receiving power from the system 2, a power test of the power converter 4 can be performed while the power storage device 13 is absorbing power from the photovoltaic power generation facility 1 and the small-capacity AC power supply device 10.

[0071] Embodiment 7 8 is a configuration diagram of a power system to which a distributed power conversion system according to embodiment 7 is applied. Note that parts that are the same as or equivalent to parts according to embodiment 6 are given the same reference numerals. Explanation of these parts will be omitted.

[0072] In the commissioning test of the power conversion system 3 for distributed power sources of embodiment 7, the control device 9 performs a current test on the test power converter 4 while controlling the power converter 4 for maintaining the AC voltage so that the voltage on the AC side of the power converter 4 for maintaining the AC voltage is constant.

[0073] When the current test of the current test power converter 4 is completed, the current tests of the remaining power converters 4 are sequentially performed in the same manner.

[0074] According to the seventh embodiment described above, during an energization test of the test power converter 4, the power converter 4 for maintaining the AC voltage is controlled so that the voltage on the AC side of the power converter 4 for maintaining the AC voltage is constant. Therefore, before receiving power from the system 2, an energization test of the power converter 4 can be performed while the power storage facility 13 is absorbing power from the photovoltaic power generation facility 1 without requiring the AC power supply device 10.

[0075] It should be noted that even if the transformer 6 is not provided in any of the first to seventh embodiments, the electrical test of the power converter 4 can be performed in a similar manner.

[0076] Furthermore, in the second to seventh embodiments, a plurality of power converters 4 for maintaining a voltage may be divided into groups, and the electrical continuity tests of the test power converters 4 may be performed simultaneously in the plurality of groups. In this case, the electrical continuity tests of all the power converters 4 may be completed in a short period of time. [Industrial Applicability]

[0077] As described above, the power distribution conversion system according to the present invention can be used in a power system. [Explanation of symbols]

[0078] REFERENCE SIGNS LIST 1 Photovoltaic power generation equipment, 2 System, 3 Power conversion system for distributed power sources, 4 Power converter, 5 DC side switch, 6 Transformer, 7 AC side switch, 8 System side switch, 9 Control device, 10 AC power supply device, 11 Load bank, 12 Test cable, 13 Energy storage equipment, 100a Processor, 100b Memory, 200 Hardware

Claims

1. A system switch; A plurality of power conversion units, each having an AC side connected in parallel to the grid switch and a DC side connected in series to a plurality of photovoltaic power generation facilities; A control device that controls the plurality of power conversion units; Equipped with Each power conversion unit is a power converter for converting DC power into AC power; A DC switch provided on a DC side of the power converter; an AC switch provided on an AC side of the power converter; Including, The control device includes: In a state where the system switch is in a cutoff state, at least one power converter is selected as a power converter under test, a DC switch corresponding to the power converter under test is in a connected state and other DC switches are in a cutoff state, an AC switch corresponding to the power converter under test is in a connected state and other AC switches are in a cutoff state, an AC power supply device and a load bank are temporarily connected to the AC side of the power converter under test, and a voltage on the AC side of the power converter under test is established. In this state, the power converter under test is controlled during a power-on test of the power converter under test. A power conversion system for distributed power sources comprising:

2. A system switch; A plurality of power conversion units, each having an AC side connected in parallel to the grid switch and a DC side connected in series to a plurality of photovoltaic power generation facilities; A control device that controls the plurality of power conversion units; Equipped with Each power conversion unit is a power converter that converts DC power to AC power or converts AC power to DC power; A DC switch provided on a DC side of the power converter; an AC switch provided on an AC side of the power converter; Including, The control device includes: In a cut-off state of the system switch, at least one power converter is selected as a power converter for maintaining an AC voltage, one power converter different from the power converter for maintaining an AC voltage is selected as a power converter under test, a DC switch corresponding to the power converter for maintaining an AC voltage is connected and the other DC switches are disconnected, the power converter for maintaining an AC voltage and an AC switch corresponding to the power converter under test are connected and the other AC switches are disconnected, the power converter for maintaining an AC voltage and the power converter under test are temporarily connected so that the DC sides of the power converter for maintaining an AC voltage and the power converter under test are in a common state, and the power converter for maintaining an AC voltage is controlled so that the voltage on the AC side of the power converter for maintaining an AC voltage is constant during an energization test of the power converter under test. A power conversion system for distributed power sources comprising:

3. A system switch; A plurality of power conversion units, each having an AC side connected in parallel with the grid switch and a DC side connected in series with a plurality of DC power sources; A control device that controls the plurality of power conversion units; Equipped with Each power conversion unit is a power converter that converts DC power to AC power or converts AC power to DC power; A DC switch provided on a DC side of the power converter; an AC switch provided on an AC side of the power converter; Including, One of the plurality of DC power sources is a power storage facility and the others are photovoltaic power generation facilities; The control device includes: In a cut-off state of the grid switch, one power converter connected to the power storage facility is selected as a power converter for maintaining an AC voltage, and one power converter different from the power converter for maintaining an AC voltage is selected as a power converter under test, the power converter for maintaining an AC voltage and a DC switch corresponding to the power converter under test are connected and the other DC switches are cut off, the power converter for maintaining an AC voltage and the AC switch corresponding to the power converter under test are connected and the other AC switches are cut off, whereby the AC sides of the power converter for maintaining an AC voltage and the power converter under test are temporarily connected to each other, and the power converter for maintaining an AC voltage is controlled so that the voltage on the AC side of the power converter for maintaining an AC voltage is constant during an energization test of the power converter under test. A power conversion system for distributed power sources comprising:

4. A system switch; A plurality of power conversion units, each having an AC side connected in parallel to the grid switch and a DC side connected in series to a plurality of photovoltaic power generation facilities; A control device that controls the plurality of power conversion units; Equipped with Each power conversion unit is a power converter that converts DC power to AC power or converts AC power to DC power; A DC switch provided on a DC side of the power converter; an AC switch provided on an AC side of the power converter; Including, The control device includes: In a cut-off state of the system switch, at least one power converter is selected as a regenerative power converter, and one power converter different from the regenerative power converter is selected as a test power converter, a DC switch corresponding to the regenerative power converter is connected and the other DC switches are cut off, the regenerative power converter and the AC switch corresponding to the test power converter are connected and the other AC switches are cut off, so that the AC sides of the regenerative power converter and the test power converter are temporarily connected to each other and temporarily connected to an AC power supply device, and in a state in which a voltage on the AC side of the test power converter is established by the AC power supply device, the regenerative power converter and the test power converter are temporarily connected so that the DC sides of the regenerative power converter and the test power converter are in a common state, and regenerative operation of the regenerative power converter is controlled so that power generated by the test power converter is regenerated to the DC side during an energization test of the test power converter. A power conversion system for distributed power sources comprising:

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