JP6984262B2 - Control device, power conversion device, control method, power conversion method, program - Google Patents

Description

The present invention relates to a control device, a power conversion device, a control method, a power conversion method, and a program.

Conventionally, in a grid interconnection system in which a distributed power source such as a photovoltaic power generation system is linked to a grid power supply, a technique for detecting an isolated operation state and / or the occurrence of flicker is known (see, for example, Patent Documents 1 to 7). ..
Patent Document 1 Japanese Patent Application Laid-Open No. 2017-127044 Patent Document 2 Japanese Patent Application Laid-Open No. 2016-131441 Patent Document 3 Japanese Patent Application Laid-Open No. 2008-193827 Patent Document 4 Japanese Patent Application Laid-Open No. 2008-259400 Patent Document 5 Japanese Patent Application Laid-Open No. 2012-060826 Patent Document 6 Japanese Patent Application Laid-Open No. 2010-074989 Patent Document 7 Japanese Patent Application Laid-Open No. 2015-144551

Since the characteristics of the power system to which the distributed power source is connected and the connection status of other distributed power sources and loads differ depending on the connection location, it is desired to appropriately prevent the occurrence of flicker in various situations.

In order to solve the above problems, in the first aspect of the present invention, there is provided a control device that controls a first power conversion device that converts power from a distributed power supply into power according to a system power supply. The control device is based on local area information including information about at least one of the power lines connected in the local area to which the first power conversion device is connected and the device other than the first power conversion device in the power system. (1) The power conversion device may include an adjustment determination unit that determines adjustment of the invalid power output characteristic used for detecting the independent operation state. The control device may include an adjustment instruction unit that instructs the first power conversion device to adjust the determined ineffective power output characteristic.

The control device uses the amount of power used by the load connected in the local area, the amount of active power output by the second power converter connected in the local area, the line impedance of the wiring connected in the local area, and the local. Further there may be a collector that collects information about at least one of the power flow states at a point in the area as at least part of the local area information.

The control device may further include a demand forecasting unit that predicts at least one of the electric energy used and the change in the electric energy of the load connected in the local area and includes it in the local area information.

The control device may further include a supply prediction unit that predicts at least one of the amount of active power output by the second power conversion device connected in the local area and the change in the amount of active power and includes it in the local area information.

The second power conversion device connected in the local area may convert the power from the distributed power source that performs photovoltaic power generation into the power corresponding to the system power supply. The supply prediction unit may predict at least one of the amount of active power output by the second power conversion device and the change in the amount of active power based on the sunshine prediction.

The adjustment determination unit has an ineffective power output characteristic in which the amount of ineffective power output by the first power conversion device is further reduced in response to an increase in the amount of active power output by the second power conversion device connected in the local area. You may decide to adjust to.

The adjustment determination unit adjusts the amount of disabled power output by the first power converter to the disabled power output characteristics that are further increased in response to the increase in the amount of power used by the load connected in the local area. You may decide.

The control device may further include a simulation processing unit that performs power simulation using a model of the local area based on the local area information. The adjustment determination unit may determine the adjustment of the reactive power output characteristic based on the result of the power simulation.

In the second aspect of the present invention, there is provided a power conversion device that converts electric power from a distributed power source into electric power according to a system power source. The power conversion device may include a switching unit capable of switching a single-phase alternating current selected from a plurality of single-phase alternating currents included in the multi-phase alternating current included in the grid power supply. The power conversion device may include an output stop unit that stops the output from the distributed power source according to the result of observing the selected single-phase alternating current.

When the voltage on the system power supply side drops below the reference value, the output stop unit stops the output from the distributed power supply according to the detection of the independent operation state in any of multiple single-phase ACs. You may let me.

The output stop unit may have an independent operation detection unit that detects the independent operation state of the distributed power source for each of the plurality of single-phase alternating currents. The output stop unit may have a voltage drop detection unit that detects a voltage drop state in which the voltage on the system power supply side drops below the reference value. The output stop unit is a stop condition that the isolated operation state is detected in the selected single-phase AC, or the independent operation state is detected in any of a plurality of single-phase ACs, and the voltage drop state is detected. It may have a condition determination unit for determining whether or not is satisfied.

In the third aspect of the present invention, a control device for controlling the power conversion device of the second aspect is provided. The control device includes a selection instruction unit that instructs two or more power conversion devices to select the same single-phase alternating current by the switching unit from a plurality of single-phase alternating currents included in the polyphase alternating current. good.

The control device may further include a selection information acquisition unit that acquires selection information of the single-phase alternating current selected in each of the plurality of power conversion devices. The selection indicator may instruct other power converters to select the most selected single-phase alternating current among the plurality of power converters.

The control device may further include a fixed state information acquisition unit that acquires fixed state information indicating single-phase alternating current used by one power conversion device having no switching unit to determine a stop condition. The selection instruction unit may instruct two or more power conversion devices to select the same single-phase alternating current as the single-phase alternating current shown in the fixed state information by the switching unit.

In the fourth aspect of the present invention, there is provided a control method for controlling a first power conversion device that converts power from a distributed power source into power according to a system power supply. The control method is based on local area information including information about at least one of a power line connected in the local area to which the first power conversion device is connected in the power system and a device other than the first power conversion device. (1) The power conversion device may include an adjustment determination step for determining adjustment of the invalid power output characteristic used for detecting the independent operation state. The control method may include an adjustment instruction step instructing the first power converter to adjust the determined reactive power output characteristic.

In a fifth aspect of the present invention, there is provided a program that operates a computer that controls a first power conversion device that converts power from a distributed power supply into power according to a system power supply. The program bases the computer on local area information, including information about at least one of the power lines and equipment other than the first power converter connected within the local area to which the first power converter is connected in the power system. , The first power conversion device may function as an adjustment determination unit for determining the adjustment of the invalid power output characteristic used for detecting the independent operation state. The program may allow the computer to function as an adjustment indicator instructing the first power converter to adjust the determined reactive power output characteristics.

In the sixth aspect of the present invention, there is provided a power conversion method for converting power from a distributed power source into power according to a grid power source. The power conversion method may include a switching stage for switching a single-phase alternating current to be selected from a plurality of single-phase alternating currents included in the multi-phase alternating current included in the grid power supply. The power conversion method may include an output stop stage in which the output from the distributed power source is stopped depending on the result of observing the selected single-phase alternating current.

In a seventh aspect of the present invention, there is provided a program that activates a computer that converts power from a distributed power source into power according to a grid power source. The program may cause the computer to function as a switching unit capable of switching the single-phase alternating current selected from the plurality of single-phase alternating currents included in the polymorphic alternating current included in the grid power supply. The program may act as an output stop to stop the output from the distributed generation, depending on the result of observing the selected single-phase alternating current.

The outline of the above invention does not list all the necessary features of the present invention. A subcombination of these feature groups can also be an invention.

The grid interconnection system which concerns on this embodiment is shown. An example of the adjustment mode of the reactive power output characteristic is shown. Shows the model of the local area. The control method of the ineffective power output characteristic performed by a control device is shown. The detection method of the isolated operation performed by the power conversion device is shown. The power conversion device in the modification is shown. Indicates an output stop section. The waveform of each single-phase AC voltage is shown. The grid interconnection system which concerns on the modification is shown. The control method of the selective phase performed by the control device is shown. The detection method of the isolated operation performed by the power conversion device is shown. An example of the configuration of the computer according to this embodiment is shown.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention to which the claims are made. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

[1. Configuration of grid interconnection system]
FIG. 1 shows a grid interconnection system 1 according to the present embodiment. The grid interconnection system 1 includes a grid power source 10 included in an electric power system provided by an electric power company or the like, and a solar power generation system, a wind power generation system, and a fuel cell power generation connected to a local area 100 forming at least a part of the electric power system. One or a plurality of distributed power sources 11 (two as an example in this embodiment) such as a system, and the system power source 10 and the distributed power source 11 are provided between the distributed power source 11 and the distributed power source 11 are supplied with power according to the system power source 10. It includes one or a plurality of power conversion devices 2 (two as an example in this embodiment) that are converted into electric power and supplied to the system power supply 10, and a control device 3 that controls the power conversion device 2 in the local area 100.

The grid power supply 10 is a facility for supplying electric power provided by an electric power company that manages an electric power system, and may be, for example, a power plant, a substation, or a transformer. The local area 100 is an area including wiring, a load, a distributed power source, and the like connected to the terminal side of the system power supply 10 in the power system. As an example, the local area 100 is located on a land located at a branch line at the end of an electric power system having a small population and low electric power demand, and as an example of the distributed power source 11, a solar power generation facility using a large number of solar panels can be provided. It is an area. In such an area, a relatively large distributed power source 11 is connected to a branch line at the end of the power system, so that the structure may be prone to flicker. In the present embodiment, the power line 110 between the power conversion device 2 and the system power supply 10 has one or a plurality of system side circuit breakers 111 that are cut off in the event of an accidental power outage, a planned power outage, a maintenance power outage, or the like of the power system. Is provided. Further, one or a plurality of loads 50 are connected to the power line 110. The power line 110 has a line impedance 1100 including an unintended inductance 1101 and a resistor 1102.

[1-1. Power converter]
The power conversion device 2 detects that the system power supply 10 side is separated from the power system due to an accidental power failure, a planned power failure, a maintenance power failure, or the like of the power system, and the distributed power supply 11 side is in an independent operation state. As an example, the power conversion device 2 according to the present embodiment disconnects between the distributed power supply 11 side and the system power supply 10 side in response to the detection of independent operation. As a result, the power conversion device 2 can ensure the safety of work / inspection on the power system side and / or protect the power distribution equipment on the power system side. The power conversion device 2 includes a power conversion unit 20, an output stop unit 21, and a communication unit 23.

[1-1-1. Power converter]
The power conversion unit 20 has an inverter 201 and an inverter control unit 203, and converts the power from the distributed power source 11 into alternating current according to the system power supply 10. The inverter 201 converts DC power or AC power from the distributed power source 11 into AC power suitable for the power system and outputs the power. The inverter control unit 203 controls the inverter control unit 203 so as to match the voltage, frequency, and phase of the AC power output by the inverter 201 with the power on the power system side.

[1-1-2. Output stop]
The output stop unit 21 detects that the system power supply 10 has become an independent operation state, and stops the output from the distributed power supply 11. The output stop unit 21 according to the present embodiment injects invalid power into the power supply path between the power conversion unit 20 and the system power supply 10, and in the case of independent operation, the frequency of the power supply power is changed due to the influence of the ineffective power injection. Detects isolated operation by utilizing large fluctuations. The output stop unit 21 includes a switch 210, a deviation parameter calculation unit 211, an reactive power injection unit 213, and an independent operation detection unit 215.

The switch 210 is provided between the power conversion unit 20 and the system power supply 10. The switch 210 connects or disconnects between the power conversion unit 20 and the system power supply 10 under the control of the independent operation detection unit 215. As a result, the switch 210 connects the power conversion unit 20 on the distributed power source 11 side to the system power supply 10 side and switches whether or not to connect the system power supply 10 to the power system. The power conversion device 2 according to the present embodiment has a configuration in which the switch 210 is built-in, but instead of this, a configuration in which the switch 210 is outside the power conversion device 2 may be adopted.

The deviation parameter calculation unit 211 calculates a frequency parameter according to the frequency of the power supplied from the distributed power supply 11, and determines the frequency parameter in a certain period (first period) and the frequency in the second period earlier than the first period. The deviation parameter according to the frequency deviation is calculated based on the parameter.

For example, the deviation parameter calculation unit 211 detects the voltage of the power supply path between the switch 210 and the system power supply 10, and calculates the frequency of the power supply power as an example of the frequency parameter from the change in the voltage. Instead of this, the deviation parameter calculation unit 211 may detect the current flowing through the wiring and calculate the frequency parameter. The deviation parameter calculation unit 211 can use the period instead of using the frequency as the frequency parameter. Since the period is nothing but the reciprocal of the frequency, it can be understood by those skilled in the art that a configuration using the period as a frequency parameter is also substantially described herein. Further, the frequency parameter may be a value that changes according to the frequency or the period, not the frequency or the period itself.

Further, the deviation parameter calculation unit 211 is predetermined from the calculated frequency parameter sequence, representative values of a plurality of frequency parameters in the first period having a predetermined time length corresponding to the current period, and predetermined values corresponding to the past period. The representative values of the plurality of frequency parameters in the second period of the time length are calculated. The representative values of the first period and the second period may be, for example, the moving average values of the frequency parameters of the first period and the second period. The first period and the second period may be continuous with each other, may be separated from each other, or may be partially overlapped with each other. The lengths of the first period and the second period may be the same or different.

Further, the deviation parameter calculation unit 211 subtracts the deviation of the representative value of the frequency parameter in the first period and the second period, that is, for example, the representative value of the frequency parameter in the first period from the representative value of the frequency parameter in the second period. Calculate the deviation parameter according to the frequency deviation. Alternatively, the deviation parameter may be a periodic deviation, or a value that changes accordingly.

When the system power supply 10 supplies multi-phase AC power, the frequency parameter and the deviation parameter may be calculated for any single-phase AC power. The deviation parameter calculation unit 211 supplies the calculated deviation parameter to the independent operation detection unit 215 and the reactive power injection unit 213.

The ineffective power injection unit 213 injects the ineffective power corresponding to the deviation parameter output by the independent operation detection unit 215 into the power supply path. The ineffective power injection unit 213 calculates the amount of ineffective power to be output according to the ineffective power output characteristic used for detecting the independent operation state of the distributed power supply 11 connected to the power conversion device 2.

The reactive power output characteristic is the relationship between the deviation parameter and the amount of reactive power to be injected to detect the isolated operating condition. In this embodiment, the reactive power output characteristic can be adjusted. For example, in the present embodiment, the ineffective power injection unit 213 adjusts one or a plurality of parameters (also referred to as an ineffective power output characteristic parameter) representing the ineffective power output characteristic. However, the ineffective power injection unit 213 may select any of the ineffective power output characteristics as the target of use from a plurality of ineffective power output characteristics. The ineffective power injection unit 213 supplies the amount of output ineffective power to the inverter control unit 203 and the amount of active power to the communication unit 36.

The independent operation detection unit 215 detects whether or not the power supply is operating independently based on the deviation parameter output by the deviation parameter calculation unit 211. As an example, the isolated operation detection unit 215 determines that the distributed power source 11 connected to the power conversion device 2 is in a state of independently supplying power when a change exceeding the reference value is detected in the deviation parameter. ..

In the present embodiment, among the parts of the output stop unit 21, the parts other than the switch 210 are control computers including a CPU such as a microcontroller, and function as the parts shown below by executing the detection program. Instead of this, parts other than the switch 210 may be realized by a dedicated circuit or a programmable circuit.

[1-1-3. Communication Department]
The communication unit 23 communicates with the control device 3 via a dedicated or general-purpose network. For example, the communication unit 23 receives various commands from the control device 3 to the output stop unit 21. Further, the communication unit 23 supplies the active power amount output by the power conversion device 2 to the control device 3.

[1-2. Control device]
The control device 3 controls at least one power conversion device 2 connected in the local area 100. As an example in the present embodiment, the control device 3 controls each power conversion device 2 connected to the local area 100. The control device 3 may be an operating condition monitoring device of the system power supply 10, or may be a power server of a power company. The control device 3 includes a collection unit 30, a demand forecast unit 31, a supply forecast unit 32, a simulation processing unit 33, an adjustment determination unit 34, an adjustment instruction unit 35, and a communication unit 36.

[1-2-1. Collection Department]
The collecting unit 30 collects at least a part of the local area information regarding the electric power in the local area 100. Here, the local area information includes information about at least one of the power line 110 and one or a plurality of devices (power conversion device 2 and / or load 50 as an example in this embodiment) connected in the local area 100. ..

For example, the collecting unit 30 is connected to the local area 100, the amount of power used by the load 50 connected to the local area 100, the amount of active power output by each power conversion device 2 connected to the local area 100, and the amount of active power output by each power conversion device 2 connected to the local area 100. It collects information about the line impedance 1100 of the power line 110 and at least one of the power flow states at a point in the local area 100.

The collection may be performed by communication, may be performed by direct input from the electric power company or the like to the control device 3, or may be performed by performing an operation on the information acquired by these. For example, information on the amount of power used by the load 50 is collected by communication with a smart meter (not shown) built in or externally connected to the load 50. Information on the amount of active power output by the power conversion device 2 is collected by communication with each power conversion device 2. In addition to / instead of the information of the active power amount output by the power conversion device 2, the invalid power amount output by the power conversion device 2 or the invalid power output characteristic of the power conversion device 2 may be used. Information on the line impedance 1100 is supplied from an electric power company or the like. The state of the power flow is calculated by the collecting unit 30 using the amount of power supplied by the system power supply 10 and the distributed power source 11, the line impedance 1100 of the power line 110, the amount of power used by the load 50, and the like. The power supply amount of the grid power supply 10 may be calculated from the power supply amount at the substation (not shown).

The collecting unit 30 may supply the collected local area information to the simulation processing unit 33 and the adjustment determination unit 34. The collection unit 30 may have a database (not shown) that stores specification information and collection information of the load 50, the power conversion device 2, the line impedance 1100, etc. connected in the local area 100, respectively.

[1-2-2. Demand Forecasting Department]
The demand forecasting unit 31 predicts the change in the electric energy and / or the electric energy of the load 50 connected in the local area 100 and includes it in the local area information. In addition to / instead of the amount of power used collected by the collecting unit 30, the demand forecasting unit 31 may include the predicted amount of power used and / or the change in the amount of power used in the local area information. The demand forecasting unit 31 may make a prediction by referring to the fluctuation pattern of the electric energy consumption within the reference period (for example, one day, one week, etc.) derived from the collection result of the electric energy consumption. The demand forecasting unit 31 may supply the forecasting result to the collecting unit 30.

[1-2-3. Supply Forecasting Department]
The supply prediction unit 32 predicts the amount of active power and / or the change in the amount of active power output by each power conversion device 2 connected in the local area 100 and includes it in the local area information. For example, when the distributed power source 11 generates solar power, the supply prediction unit 32 outputs an active electric energy and / or an active power by the power conversion device 2 connected to the distributed power source 11 based on the sunshine prediction. Predict changes in quantity. The supply prediction unit 32 may include, in addition to / instead of the active power amount collected by the collection unit 30, the predicted active power amount and / or the change in the active power amount in the local area information. The supply prediction unit 32 may make a prediction by referring to the fluctuation pattern of the active power amount within the reference period (for example, one day, one week, etc.) derived from the collection result of the active power amount. The supply prediction unit 32 may supply the prediction result to the collection unit 30.

[1-2-4. Simulation processing unit]
The simulation processing unit 33 performs power simulation using the model of the local area 100 based on the local area information. For example, the simulation processing unit 33 builds a model representing the power relationship between the elements connected in the local area 100 from the local area information, and simulates the power state at each point of the wiring. The simulation processing unit 33 may detect by simulation whether or not flicker is generated due to the output of the reactive power. Flicker is a phenomenon in which the voltage of the power supply path is excited by the injection of the reactive power by the reactive power injection unit 213, and the voltage fluctuation in the power supply path periodically exceeds the flicker reference defined in advance. The periodic voltage fluctuation here is not a change in the instantaneous voltage at the AC frequency in the AC voltage, but is mainly the maximum voltage (or effective voltage or average voltage) in a period (for example, several Hz) longer than the AC frequency. It is a fluctuation.

The amount of power supplied from the grid power supply 10, the power consumption of each load 50, the output power of each distributed power supply 11, the connection relationship between the power system nodes, the load 50 and the distributed power supply 11, and all the characteristics of the wiring. It is self-evident to those skilled in the art that a highly accurate model can be constructed and a power state simulation can be performed with the above information. Even if there is insufficient information to realize an accurate model, the possibility of flicker can be predicted to some extent by replacing it with a simpler model and performing a simulation. The simulation processing unit 33 may supply the simulation result to the adjustment determination unit 34.

[1-2-5. Adjustment decision unit]
The adjustment determination unit 34 determines to adjust the ineffective power output characteristics of the plurality of power conversion devices 2 based on the local area information. The adjustment determination unit 34 may determine the adjustment based on the result of the power simulation. The information of the target power conversion device 2 for which the adjustment is determined may be excluded from the local area information when the adjustment of the power conversion device 2 is determined.

As an example in the present embodiment, the adjustment determination unit 34 also determines how to adjust the reactive power output characteristic. The adjustment determination unit 34 may determine the adjustment direction of the reactive power output characteristic (for example, the direction of reducing or increasing the output reactive power), or the adjustment amount of the reactive power output characteristic (example). The magnitude of changing the output reactive power) may be determined. The adjustment determination unit 34 may determine the adjusted invalid power output characteristic parameter.

For example, the adjustment determination unit 34 is output by the target power conversion device 2 in response to an increase in the amount of active power output by the other one or a plurality of power conversion devices 2 connected in the local area 100. It is decided to adjust the amount of idle power to a smaller amount of idle power output characteristics. In addition to / instead of this, the adjustment determination unit 34 responds to the expectation that the amount of active power output by the other one or more power conversion devices 2 connected in the local area 100 will increase. , It is determined to adjust the amount of invalid power output by the target power conversion device 2 to the reduced invalid power output characteristic. The adjustment determination unit 34 may decide to adjust the ineffective power output characteristic of the target power conversion device 2 so that the amount of ineffective power output by the target power conversion device 2 becomes small.

Further, the adjustment determination unit 34 increases the amount of reactive power output by the target power conversion device 2 in response to the increase in the amount of power used by the load 50 connected in the local area 100. Decide to adjust to the output characteristics. In addition to / instead of this, the adjustment determination unit 34 is output by the target power conversion device 2 in response to the expected increase in the amount of power used by the load 50 connected in the local area 100. It is decided to adjust the amount of reactive power to a more increased reactive power output characteristic. The adjustment determination unit 34 may decide to adjust the ineffective power output characteristic of the target power conversion device 2 so that the amount of ineffective power output by the target power conversion device 2 becomes large.

The adjustment determination unit 34 is output by the target power conversion device 2 in response to the increase in the portion of the local area 100 where the reverse power flow is generated, that is, the portion to which power is supplied from the distributed power source 11. It may be decided to adjust the amount of reactive power generated to a more reduced reactive power output characteristic. Further, the adjustment determination unit 34 acquires information on whether or not flicker has occurred from the simulation processing unit 33, the power conversion device 2 and / or the electric power supplier, and when the flicker occurs, the target power conversion device 2 It may be decided to adjust the amount of ineffective power output by the method to a lesser ineffective power output characteristic. Further, the adjustment determination unit 34 increases the adjustment amount when flicker still occurs even after applying the adjusted reactive power output characteristic, and / or causes flicker when the adjusted reactive power output characteristic is applied. Learning may be performed so as to reduce the adjustment amount when it does not occur.

[1-2-6. Adjustment indicator]
The adjustment instruction unit 35 instructs the target power conversion device 2 to adjust the determined invalid power output characteristic. In the present embodiment, the adjustment instruction unit 35 further instructs the power conversion device 2 how to adjust the invalid power output characteristic. The adjustment instruction unit 35 may give an adjustment instruction via the communication unit 36.

[1-2-7. Communication Department]
The communication unit 36 communicates with the power conversion device 2 and the load 50 connected in the local area 100 via a dedicated or general-purpose network.

According to the above control device 3, the adjustment of the reactive power output characteristic used for detecting the independent operation state is determined based on the local area information, and the target power conversion device 2 is instructed. Therefore, in the power conversion device 2, since the independent operation state can be detected by using the invalid power output characteristic that does not cause flicker, the independent operation state can be detected while preventing the occurrence of flicker.

Further, the control device 3 provides information on at least one of the amount of power used by the load 50, the amount of active power output by the power conversion device 2, the line impedance 1100 of the power line 110, and the state of the power flow in the local area information. Collect at least as part. Therefore, it is possible to reliably set the reactive power output characteristic so that flicker does not occur.

[1-3. Reactive power output characteristics]
FIG. 2 shows an example of the adjustment mode of the reactive power output characteristic. The horizontal axis of this figure shows the deviation parameter (frequency deviation as an example) received from the deviation parameter calculation unit 211, and the vertical axis shows the reactive power to be injected into the power supply path.

The ineffective power injection unit 213 calculates the ineffective power to be injected according to the deviation parameter received from the deviation parameter calculation unit 211 from the graph of FIG. 2, and injects the calculated ineffective power into the power supply path. To control. As a result, the reactive power injection unit 213 injects the reactive power in a direction that promotes the deviation generated in the power supply path, and facilitates the detection of the independent operation state.

In the range where the deviation parameter is in the range of −a to + a, the reactive power injection unit 213 controls the injection amount of the reactive current according to the deviation parameter to be relatively small. As a result, when the distributed power supply 11 is interconnected with the power system and the deviation between the distributed power supply 11 is small, the ineffective power injection unit 213 injects a large amount of ineffective power into the power supply path to disturb the power system. To prevent. In the range where the deviation parameters are −b to −a and + a to + b, the reactive power injection unit 213 controls the injection amount of the reactive power according to the deviation parameter relatively large. As a result, the reactive power injection unit 213 injects a relatively large amount of reactive power into the power supply path in response to the fact that the distributed power source 11 is separated from the power system and the magnitude of the deviation parameter becomes a or more, and is independent. Make it easier to detect the operating status. In the range where the deviation parameter is −b or less or + b or more, the reactive power injection unit 213 maintains the minimum value or the maximum value without further increasing the injection amount of the reactive power. This prevents the reactive power injection unit 213 from injecting excessive reactive power into the power supply path.

Here, the solid line graph in the figure shows the ineffective power output characteristic before adjustment, and the broken line graph shows the ineffective power output characteristic after adjustment. In the present embodiment, as an example, the absolute value of the maximum value and the minimum value of the output reactive power is used as the reactive power output characteristic parameter, and these are adjusted so as to be small. Alternatively / additionally, the reactive power output characteristic parameter may be the value of the deviation parameter when the injection amount of the reactive power becomes the maximum value / the minimum value, that is, the value of ± b, or the slope of the graph. In this case, the reactive power output characteristic may be adjusted so that the range of −b to + b becomes large, or the slope of the graph may be adjusted to be small. Within the range of −a to + a, the reactive power output characteristics may be the same before and after adjustment. The reactive power output characteristic may be adjusted so that the absolute values of the maximum and minimum values of the output reactive power are large, or the range of −b to + b is small. However, it may be adjusted so that the slope of the graph becomes large.

[1-4. Power simulation]
FIG. 3 shows a model of the local area 100. The arrows in the figure indicate the active power supply direction. As an example in the present embodiment, the simulation processing unit 33 uses the current values I0 to I4, the inductances L1 and L2, the resistance values R1 and R2, etc. collected as the local area information, and the portion of the reverse power flow in the local area 100. To model. Further, the simulation processing unit 33 uses the obtained model to simulate whether or not flicker is generated due to the output of the reactive power. For example, the simulation processing unit 33 estimates the voltage fluctuation when injecting the amount of ineffective power specified by the ineffective power output characteristic for each injection frequency (for example, a plurality of frequencies of 6 to 7 Hz), and the estimated voltage. It may be detected that flicker occurs when the multiplication result of the fluctuation value and the predetermined coefficient for each frequency exceeds the threshold value at any frequency.

[2. How to run in a grid-connected system]
[2-1. How it is done in the controller]
FIG. 4 shows a control method of the reactive power output characteristic performed by the control device 3. The control device 3 controls the ineffective power output characteristic of each power conversion device 2 by performing the processes of steps S101 to S105. This operating flow may be executed when the situation of the power system changes. In such a case, for example, when the amount of power generation is adjusted by the grid power supply 10 and / or the distributed power supply 11, or when the sunshine changes, the distributed power supply 11 and the power conversion device 2 are newly added in the grid interconnection system 1. For example, when it is started in.

First, in step S101, the collecting unit 30 acquires local area information. In step S101, the information predicted by the demand forecasting unit 31 and the supply forecasting unit 32 may be included in the local area information. Further, the power simulation may be performed by the simulation processing unit 33.

Next, in step S103, the adjustment determination unit 34 determines whether or not to adjust the reactive power output characteristics for each of the plurality of power conversion devices 2 based on the local area information. The adjustment determination unit 34 may also make a determination using the simulation result.

Then, in step S105, the adjustment instruction unit 35 instructs the power conversion device 2 for which the adjustment of the invalid power output characteristic is determined to perform the adjustment, and ends the operation flow of the present figure.

According to the above method, the adjustment of the invalid power output characteristic can be determined based on the local area information, and can be instructed to the target power conversion device 2.

[2-2. How to do it with a power converter]
FIG. 5 shows a detection method of independent operation performed by the power conversion device 2. The power conversion device 2 detects the independent operation by performing the processes of steps S201 to S213.

First, in step S201, the reactive power injection unit 213 sets the reactive power output characteristic parameter. For example, the reactive power injection unit 213 sets the reactive power output characteristic parameter to the initial value when the power conversion device 2 is started. When the control device 3 instructs the adjustment, the reactive power injection unit 213 adjusts the reactive power output characteristic parameter according to the instruction. The reactive power injection unit 213 may maintain the reactive power output characteristic parameter when adjustment is not instructed.

Next, in step S203, the deviation parameter calculation unit 211 calculates a frequency parameter according to the frequency of the power supply power.

Next, in step S205, the deviation parameter calculation unit 211 calculates the frequency parameter in the first period and the frequency parameter in the second period, and calculates the deviation parameter according to the frequency deviation based on these.

Next, in step S207, the independent operation detection unit 215 detects whether or not the distributed power source 11 is operating independently based on the deviation parameter. The solitary operation detection unit 215 may use various known methods such as the methods of Patent Documents 1 to 3 as the method of detecting the solitary operation.

Next, in step S209, the solitary operation detection unit 215 advances the process to step S211 according to the fact that the solitary operation is not detected, and proceeds to the process to step S213 according to the detection of the solitary operation.

In step S211 of the power conversion unit 20, the reactive power injection unit 213 injects the reactive power corresponding to the deviation parameter calculated in step S205 and the reactive power output characteristic parameter set in step S201 into the power supply path. Instruct to the inverter control unit 203 inside. Then, the power conversion device 2 advances the process to step S201.

In step S213, the independent operation detection unit 215 shuts off the switch 210, disconnects the system power supply 10 in the independent operation state from the power system, and ends the operation flow of the present figure. The power conversion device 2 may be configured so that the switch 210 can be manually switched to the connected state, and may be manually returned to the interconnected state when the power supply from the power system is resumed. Instead, the power conversion device 2 monitors the power supply path between the output stop unit 21 and the system power supply 10 even while the switch 210 is shut off, and switches according to the fact that the power supply from the power system is resumed. The 210 may be switched to the connected state.

According to the above method, since the independent operation state can be detected by using the reactive power output characteristic that does not cause flicker, the independent operation state can be detected while preventing the occurrence of flicker.

[3. Modification example of power converter]
FIG. 6 shows the power conversion device 2A in the modified example. The power conversion device 2A uses the power from the power lines 112 (P) and 112 (N) on the positive electrode side and the negative electrode side of the distributed power supply 11 as multi-phase AC power according to the system power supply 10 (as an example in this modification). It is converted into three-phase AC power) and supplied to the system power supply 10. The power conversion device 2A supplies a plurality of single-phase AC power having different phases to each of the plurality of power lines 110 (L1) to 110 (L3). The power conversion device 2A includes an output stop unit 21A.

The output stop unit 21A is a distributed power source according to the result of observing any single-phase alternating current selected from the three single-phase alternating currents supplied between the power lines 110 (L1) to 110 (L3). The output from 11 is stopped. In addition to this, in this modification, when the voltage on the system power supply 10 side of the output stop unit 21A drops below the reference value, the independent operation state is detected in any of the three single-phase alternating currents. The output from the distributed power supply 11 is stopped according to the above. The output stop unit 21A has a switch 210 on each power line 110 (L1) to 110 (L3), and also has a deviation parameter calculation unit 211A, an independent operation detection unit 215A, a switching unit 216, a voltage drop detection unit 217, and a condition determination unit 218. Has.

The deviation parameter calculation unit 211A calculates the frequency parameter, and thus the deviation parameter, for each of the three single-phase alternating currents included in the three-phase alternating current. The method for calculating the frequency parameter and the deviation parameter for each single-phase alternating current may be the same as that for the deviation parameter calculation unit 211. The deviation parameter calculation unit 211 supplies the calculated deviation parameter to the independent operation detection unit 215A and the reactive power injection unit 213.

The independent operation detection unit 215A detects the independent operation state of the distributed power source 11 for any one single-phase alternating current selected from the three single-phase alternating currents included in the three-phase alternating current. As an example in this modification, the independent operation detection unit 215A detects the independent operation state of the distributed power source 11 for each of the three single-phase alternating currents. The method for detecting the isolated operation state for each single-phase alternating current may be the same as that for the isolated operation detection unit 215. The independent operation detection unit 215A may supply the detection result to the switching unit 216 and the condition determination unit 218.

The switching unit 216 can switch the single-phase alternating current selected from the three single-phase alternating currents included in the three-phase alternating current. The switching unit 216 supplies the detection result of the independent operation state in the selected single-phase alternating current to the condition determination unit 218.

In this modification, as an example, each single-phase AC is AC power between each power line 110, but AC power between each power line 110 and the ground or ground potential may be used. Further, the switching unit 216 switches the single-phase alternating current according to the power conversion device 2A receiving the switching operation, but may switch according to the communication unit 23 receiving the switching signal. Which single-phase alternating current is selected may be indicated by the power conversion device 2A and / or the control device 3.

The voltage drop detection unit 217 detects a voltage drop state in which the voltage on the system power supply 10 side drops below the reference value. In this modification, the voltage drop detection unit 217 detects the voltage drop state for each single-phase alternating current included in the three-phase alternating current. The voltage drop detection unit 217 may detect a voltage drop in the power supply path between the switch 210 and the system power supply 10. The voltage drop detection unit 217 may supply the detection result to the condition determination unit 218. The reference value of the voltage may be arbitrarily set based on the value determined for each electric power company to be connected or by trial and error.

The condition determination unit 218 determines whether or not the stop condition of the distributed power source 11 is satisfied. In this modification, as the stop condition, the single-phase AC selected by the switching unit 216 is detected as a single-phase AC, or the single-phase AC is detected as one of the three single-phase ACs, and the voltage drop state is determined. What was detected is used. When it is determined that any of the stop conditions is satisfied, the condition determination unit 218 shuts off each switch 210.

According to the above power conversion device 2A, the single-phase alternating current for detecting the independent operation state is switched by the switching unit 216 to be aligned with the other power conversion device 2. Therefore, since it is possible to detect the frequency change and the independent operation state at the same single-phase AC zero cross timing as the other power conversion device 2, the timing of detecting the independent operation state is aligned with the other power conversion device 2. Can be done. Therefore, it is possible to prevent a part of the power conversion device 2 from continuing the operation by the FRT function in spite of the independent operation state.

Further, since which single-phase alternating current is selected as the target for detecting the independent operation state is displayed on the power conversion device 2A and / or the control device 3, the single-phase alternating current is surely aligned by checking the display. be able to.

In addition to stopping the output depending on the detection result of the selected single-phase AC, when the voltage on the system power supply 10 side has dropped below the reference value, the independent operation state was detected by another single-phase AC. Since the output is stopped even in response to this, it is possible to reliably prevent the continuation of the operation in the independent operation state.

[3-1. Configuration example of output stop unit]
FIG. 7 shows the output stop unit 21A. However, the switch 210 is not shown in the figure.

The voltage drop detection section 217 of the output stop section 21A detects the voltage drop state for each of the three-phase AC voltages. For example, the voltage drop detection unit 217, a power line 110 (L1) and 110 (L2) voltage _{V L1L2} between a power line 110 (L2) and 110 (L3) voltage between _{V L2L3,} power line 110 (L3) and 110 The voltage drop state is detected with respect to _{the voltage V L3L1} between (L1). The voltage drop detection unit 217 supplies a signal indicating whether or not a voltage drop is detected in any single-phase alternating current to the condition determination unit 218. In this modification, as an example, this signal becomes high when a voltage drop is detected in any single-phase alternating current.

The deviation parameter calculation unit 211A calculates the deviation parameter from each of the three-phase AC voltages. For example, the deviation parameter calculation unit 211A calculates the deviation parameter P _{VL1L2 from the voltage VL1L2} between the power lines 110 (L1) and 110 (L2). Further, the deviation parameter calculation unit 211A calculates the deviation parameter P _{VL2L3 from the voltage VL2L3} between the power lines 110 (L2) and 110 (L3). Further, the deviation parameter calculation unit 211A calculates the deviation parameter P _{VL3L1 from the voltage VL3L1} between the power lines 110 (L3) and 110 (L1). The deviation parameter calculation unit 211A _supplies the calculated deviation parameters P VL1L2, P _VL2L3 , and P _VL3L1 to the independent operation detection unit 215A, respectively.

The independent operation detection unit 215A detects the independent operation state of the distributed power source 11 for each of the three single-phase alternating currents. For example, the isolated operation detection unit 215A detects the isolated operation state from the deviation parameter P _{VL1L2 for the single-phase AC voltage VL1L2.} Further, the independent operation detection unit 215A detects the independent operation state from the deviation parameter P _{VL2L3 for the single-phase AC voltage VL2L3.} Further, the independent operation detection unit 215A detects the independent operation state from the deviation parameter P _{VL3L1 for the single-phase AC voltage VL3L1.} Islanding detection unit 215A supplies the detection result detected signal representative of the _{S VL1L2, S VL2L3, S VL3L1} to each switching unit 216 and the condition determining unit 218. In this modification, as an example, the detection signals S _VL1L2 , S _VL2L3 , and S _VL3L1 become high when the independent operation state is detected.

The switching unit 216 is a selector switch, and _{supplies any of the detection signals S VL1L2} , S _VL2L3 , and S _VL3L1 to the condition determination unit 218. As a result, a signal indicating whether or not the independent operation state is detected by the selected single-phase alternating current is supplied to the condition determination unit 218.

The condition determination unit 218 has an OR circuit 2181, 2185 and an AND circuit 2183.
_{The OR circuit 2181 supplies a signal obtained by ORing} the detection signals S VL1L2, S _VL2L3 , and S _VL3L1 supplied from the isolated operation detection unit 215A to the AND circuit 2183. As a result, a signal indicating whether or not the independent operation state is detected in any of the three single-phase alternating currents is supplied to the AND circuit 2183.

The AND circuit 2183 supplies the OR circuit 2185 with a signal obtained by ANDing the signal supplied from the OR circuit 2181 and the signal supplied from the voltage drop detection unit 217. As a result, a signal indicating whether or not the independent operation state is detected in any single-phase AC and the voltage drop is detected in any single-phase AC is supplied to the OR circuit 2185.

The OR circuit 2185 supplies the switch 210 with a signal obtained by ORing the signal supplied from the switching unit 216 and the signal supplied from the AND circuit 2183. As a result, either the isolated operation state is detected in the selected single-phase AC, or the independent operation state is detected in any of the three single-phase ACs, and the voltage drop state is detected. When the condition is satisfied, a stop command is supplied to the switch 210.

[3-2. Single-phase AC zero cross timing]
FIG. 8 shows the waveforms of the single-phase AC voltages _VL1L2 , _VL2L3 , and _VL3L1. Here, the horizontal axis in the figure indicates time (ms), and the vertical axis indicates the voltage value (V). The values on the vertical and horizontal axes are examples, and are not limited to these.

In this modification, the frequency and period of single-phase alternating current are calculated from the rising zero-cross timing interval. For example, the frequency parameters of the single-phase AC voltage _VL1L2 are calculated, for example, at zero cross timings of around 20 ms, around 40 ms, and so on. _Further , the frequency parameters of the single-phase AC voltage VL2L3 are calculated, for example, at zero cross timings of around 26.7 ms, around 46.7 ms, and so on. _Further , the frequency parameters of the single-phase AC voltage VL3L1 are calculated, for example, at zero cross timings of around 33.3 ms, around 53.3 ms, and so on. Therefore, if the single-phase alternating current for detecting the independent operation state is different between the power conversion devices 2A, the detection timing may be different by 13.3 ms at the maximum.

On the other hand, in the power conversion device 2A of this modification, since the single-phase alternating current for calculating the frequency parameter and the deviation parameter can be aligned between the power conversion devices 2, the timing of detecting the independent operation state can be set by the power conversion device. It can be aligned between two.

[4. Modification example of grid interconnection system]
[4-1. Configuration of system interconnection system of modified example]
FIG. 9 shows a grid interconnection system 1A according to a modified example. The grid interconnection system 1A controls two or more power conversion devices 2A (three as an example in the modified example) provided between the grid power supply 10 and the distributed power supply 11, and the power conversion device 2A in the local area 100. The control device 3A is provided. The grid interconnection system 1A may further include one power conversion device 2 as long as it includes two or more power conversion devices 2A.

The control device 3A aligns the selected single-phase alternating current between the power conversion devices 2A. When the power conversion device 2 is present in the grid interconnection system 1A, the control device 3A aligns the selected single-phase AC between the power conversion device 2 and the power conversion device 2A. The control device 3A has a selection information acquisition unit 37, a fixed state information acquisition unit 38, and a selection instruction unit 39.

The selection information acquisition unit 37 acquires the selection information of the single-phase alternating current selected in each of the plurality of power conversion devices 2A. The selection information acquisition unit 37 supplies the acquired selection information to the selection instruction unit 39.

The fixed state information acquisition unit 38 acquires fixed state information from one power conversion device 2 that does not have the switching unit 216. Here, the fixed state information is information indicating single-phase alternating current used by the power conversion device 2 for determining a stop condition. The fixed state information acquisition unit 38 supplies the acquired fixed state information to the selection instruction unit 39.

The selection instruction unit 39 selects the same single-phase alternating current from the plurality of single-phase alternating currents included in the multi-phase alternating current included in the grid power supply 10 for the two or more power conversion devices 2A by the switching unit 216. Instruct. For example, the selection instruction unit 39 determines one single-phase alternating current to be selected by using the information supplied from the selection information acquisition unit 37 and / or the fixed state information acquisition unit 38, and instructs each power conversion device 2A. ..

According to the above control device 3A, the single-phase alternating current to be selected can be aligned between the power conversion devices 2A without performing an operation on each power conversion device 2A. Therefore, the timing of detecting the independent operation state can be easily aligned.

[4-2. Method to be executed in the system interconnection system of the modified example]
[4-2-1. How it is done in the controller]
FIG. 10 shows a method of controlling the selective phase performed by the control device 3A. The control device 3A controls the single-phase alternating current selected by each power conversion device 2A by performing the processes of steps S301 to S305. It should be noted that this operation flow may be executed when the distributed power source 11 and the power conversion device 2 are newly started in the grid interconnection system 1A. Further, this operation flow may be performed in parallel with the operation flow of FIG. 4 described above.

First, in step S301, the selection information acquisition unit 37 acquires the selection information of the single-phase alternating current selected in each of the plurality of power conversion devices 2A. For example, the selection information acquisition unit 37 acquires the single-phase alternating current information selected by the switching unit 216 of the power conversion device 2A via the communication unit 36.

Next, in step S303, the fixed state information acquisition unit 38 acquires the fixed state information from one power conversion device 2 that does not have the switching unit 216. For example, the fixed state information acquisition unit 38 acquires fixed state information from the power conversion device 2 via the communication unit 36.

Next, in step S305, the selection instruction unit 39 instructs the switching unit 216 of the power conversion device 2A to select the same single-phase alternating current, and ends the operation flow of this figure. For example, the selection instruction unit 39 instructs another power conversion device 2A to select the single-phase alternating current most selected among the plurality of power conversion devices 2A. As an example, the selection instruction unit 39 instructs each power conversion device 2A that has not selected the most selected single-phase alternating current to select the single-phase alternating current. In addition to / instead of this, when the power conversion device 2 having no switching unit 216 exists in the grid interconnection system 1A, the selection instruction unit 39 uses the fixed state information acquired from the power conversion device 2 as the fixed state information. Instruct each power converter 2A to select the same single-phase alternating current as the indicated single-phase alternating current.

According to the above method, since each power conversion device 2A selects the most selected single-phase alternating current, it is possible to efficiently arrange the single-phase alternating current. Further, since the single-phase alternating current shown in the fixed state information is selected by each power conversion device 2A, even if the power conversion device 2 having no switching unit 216 exists in the grid interconnection system 1A, the selection is made. It is possible to surely align the single-phase alternating current to be performed.

[4-2-2. How to do it with a power converter]
FIG. 11 shows a detection method of the isolated operation performed by the power conversion device 2A. The power conversion device 2A detects the independent operation by performing the processes of steps S401 to S419.

First, in step S401, the power conversion device 2A determines whether or not a single-phase AC selection instruction has been received from the control device 3A. The power conversion device 2A shifts the process to step S405 according to the determination in step S401 that the selection instruction has not been received, and shifts the process to step S403 according to the determination that the selection instruction has been received.

In step S403, the switching unit 216 switches the single-phase alternating current to be selected according to the selection instruction.

Next, in steps S405 to S411, the power conversion device 2A sets the disabled power output characteristic parameter, calculates the frequency parameter and the deviation parameter, and detects the independent operation state in the same manner as in steps S201 to S207 described above. However, in step S411, the solitary operation detection unit 215 detects the solitary operation state for the selected single-phase alternating current and each of the other single-phase alternating currents.

Next, in step S413, the voltage drop detection unit 217 detects the voltage drop state. The process of step S413 may be performed between steps S403 and S411.

Next, in step S415, the condition determination unit 218 determines whether or not the stop condition that the single-phase alternating current has been detected as a result of observing the selected single-phase alternating current is satisfied. Further, the condition determination unit 218 determines whether or not the stop condition that the independent operation state is detected by any of the three single-phase alternating currents and the voltage drop state is detected is satisfied. The power conversion device 2A shifts the process to step S417 according to the determination that the stop condition is not satisfied in step S415, and shifts the process to step S419 according to the determination that the stop condition is satisfied.

In step S417, the reactive power injection unit 213 injects the reactive power in the same manner as in step S211 described above. Then, the power conversion device 2A advances the process to step S401.

In step S419, the condition determination unit 218 shuts off the switch 210 and disconnects the system power supply 10 in the independent operation state from the power system in the same manner as in step S213 described above, and ends the operation flow of this figure. As a result, the output from the distributed power source 11 is stopped according to the result of observing the selected single-phase alternating current. Further, when the voltage on the system power supply 10 side is lower than the reference value, the output from the distributed power supply 11 is stopped according to the detection of the independent operation state in any of the three single-phase alternating currents. To.

According to the above method, the single-phase alternating current that detects the independent operation state can be aligned with the other power conversion device 2. Therefore, since the timing of detecting the independent operation state can be aligned with that of the other power conversion device 2, it is possible to prevent a part of the power conversion device 2 from continuing the operation by the FRT function regardless of the independent operation state. can do.

In the above embodiment and modification, the control device 3 has been described as having a collecting unit 30, a demand forecasting unit 31, a supply forecasting unit 32, a simulation processing unit 33, and a communication unit 36, but at least one of them. It may not have. In this case, the adjustment determination unit 34 may determine the adjustment of the reactive power output characteristic based on the input local area information.

Further, although the power conversion device 2A has been described as having the voltage drop detection unit 217 and the condition determination unit 218, it may not have these. In this case, the independent operation detection unit 215 may shut off each switch 210 when the independent operation state is detected by the selected single-phase alternating current. Further, the switching unit 216 is provided between the power lines 110 (L1) to 110 (L3) and the deviation parameter calculation unit 211A, and supplies only the line voltage corresponding to the selected single-phase alternating current to the deviation parameter calculation unit 211A. You can do it.

Further, although the control device 3A has been described as having the selection information acquisition unit 37 and the fixed state information acquisition unit 38, it may not have at least one of them. In this case, the selection instruction unit 39 may instruct each power conversion device 2A which single-phase alternating current is to be selected according to the operation.

In addition, various embodiments of the present invention may be described with reference to flowcharts and block diagrams, where the block serves (1) the stage of the process in which the operation is performed or (2) the role of performing the operation. It may represent a section of the device it has. Specific stages and sections are implemented by dedicated circuits, programmable circuits supplied with computer-readable instructions stored on a computer-readable medium, and / or processors supplied with computer-readable instructions stored on a computer-readable medium. It's okay. Dedicated circuits may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuits are memory elements such as logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, flip-flops, registers, field programmable gate arrays (FPGAs), programmable logic arrays (PLA), etc. May include reconfigurable hardware circuits, including, etc.

The computer readable medium may include any tangible device capable of storing instructions executed by the appropriate device, so that the computer readable medium having the instructions stored therein is specified in a flow chart or block diagram. It will be equipped with a product that contains instructions that can be executed to create means for performing the operation. Examples of the computer-readable medium may include an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, and the like. More specific examples of computer-readable media include floppy (registered trademark) disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), Electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disk read-only memory (CD-ROM), digital versatile disk (DVD), Blu-ray (RTM) disk, memory stick, integrated A circuit card or the like may be included.

Computer-readable instructions are assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or object-oriented programming such as Smalltalk, JAVA®, C ++, etc. Includes either source code or object code written in any combination of one or more programming languages, including languages, and traditional procedural programming languages such as the "C" programming language or similar programming languages. good.

Computer-readable instructions are used locally or to a local area network (LAN), wide area network (WAN) such as the Internet, to a general purpose computer, a special purpose computer, or the processor or programmable circuit of another programmable data processing device. ) May execute computer-readable instructions to create means for performing the operations specified in the flowchart or block diagram. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, and the like.

FIG. 12 shows an example of a computer 2200 in which a plurality of aspects of the present invention may be embodied in whole or in part. The program installed on the computer 2200 can cause the computer 2200 to function as an operation associated with the device according to an embodiment of the present invention or as one or more sections of the device, or the operation or the one or more. Sections can be run and / or the computer 2200 can be run a process according to an embodiment of the invention or a stage of such process. Such a program may be run by the CPU 2212 to cause the computer 2200 to perform certain operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.

The computer 2200 according to this embodiment includes a CPU 2212, a RAM 2214, a graphic controller 2216, and a display device 2218, which are interconnected by a host controller 2210. The computer 2200 also includes input / output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the host controller 2210 via the input / output controller 2220. There is. The computer also includes legacy input / output units such as ROM 2230 and keyboard 2242, which are connected to the input / output controller 2220 via an input / output chip 2240.

The CPU 2212 operates according to a program stored in the ROM 2230 and the RAM 2214, thereby controlling each unit. The graphic controller 2216 acquires the image data generated by the CPU 2212 in a frame buffer or the like provided in the RAM 2214 or itself so that the image data is displayed on the display device 2218.

The communication interface 2222 communicates with other electronic devices via the network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads the program or data from the DVD-ROM 2201 and provides the program or data to the hard disk drive 2224 via the RAM 2214. The IC card drive reads programs and data from the IC card and / or writes programs and data to the IC card.

The ROM 2230 contains a boot program or the like executed by the computer 2200 at the time of activation, and / or a program depending on the hardware of the computer 2200. The input / output chip 2240 may also connect various input / output units to the input / output controller 2220 via a parallel port, serial port, keyboard port, mouse port, and the like.

The program is provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The program is read from a computer-readable medium, installed on a hard disk drive 2224, RAM 2214, or ROM 2230, which is also an example of a computer-readable medium, and executed by the CPU 2212. The information processing described in these programs is read by the computer 2200 and provides a link between the program and the various types of hardware resources described above. The device or method may be configured to implement the manipulation or processing of information in accordance with the use of computer 2200.

For example, when communication is executed between the computer 2200 and an external device, the CPU 2212 executes a communication program loaded in the RAM 2214, and performs communication processing on the communication interface 2222 based on the processing described in the communication program. You may order. Under the control of the CPU 2212, the communication interface 2222 reads and reads transmission data stored in a transmission buffer processing area provided in a recording medium such as a RAM 2214, a hard disk drive 2224, a DVD-ROM 2201, or an IC card. The data is transmitted to the network, or the received data received from the network is written to the reception buffer processing area provided on the recording medium.

Further, the CPU 2212 makes the RAM 2214 read all or necessary parts of the file or the database stored in the external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM2201), and the IC card. Various types of processing may be performed on the data on the RAM 2214. The CPU 2212 then writes back the processed data to an external recording medium.

Various types of information such as various types of programs, data, tables, and databases may be stored in recording media and processed. The CPU 2212 describes various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, and information retrieval described in various parts of the present disclosure with respect to the data read from the RAM 2214. Various types of processing may be performed, including / replacement, etc., and the results are written back to RAM 2214. Further, the CPU 2212 may search for information in a file, database, or the like in the recording medium. For example, when a plurality of entries each having an attribute value of the first attribute associated with the attribute value of the second attribute are stored in the recording medium, the CPU 2212 specifies the attribute value of the first attribute. Search for an entry that matches the condition from the plurality of entries, read the attribute value of the second attribute stored in the entry, and associate it with the first attribute that satisfies the predetermined condition. The attribute value of the second attribute obtained may be acquired.

The program or software module described above may be stored on or near a computer 2200 on a computer-readable medium. Also, a recording medium such as a hard disk or RAM provided within a dedicated communication network or a server system connected to the Internet can be used as a computer readable medium, thereby providing the program to the computer 2200 over the network. do.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that the form with such changes or improvements may be included in the technical scope of the present invention.

The order of execution of each process such as operation, procedure, step, step in the device, system, program, and method shown in the claims, specification, and drawings is particularly "before" and "prior to". It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the scope of claims, the specification, and the operation flow in the drawings are explained using "first", "next", etc. for convenience, it means that it is essential to carry out in this order. It's not a thing.

1 (1A) grid interconnection system, 2 (2A) power conversion device, 3 (3A) control device, 10 grid power supply, 11 distributed power supply, 20 power conversion unit, 21 (21A) output stop unit, 23 communication unit, 30 Collection unit, 31 Demand forecast unit, 32 Supply forecast unit, 33 Simulation processing unit, 34 Adjustment decision unit, 35 Adjustment instruction unit, 36 Communication unit, 37 Selection information acquisition unit, 38 Fixed state information acquisition unit, 39 Selection instruction unit, 50 load, 100 local area, 110 power line, 111 system side breaker, 112 power line, 201 inverter, 203 inverter control unit, 210 switch, 211 (211A) deviation parameter calculation unit, 213 invalid power injection unit, 215 (215A) alone Operation detection unit, 216 switching unit, 217 voltage drop detection unit, 218 condition determination unit, 1100 line impedance, 1101 inductance, 1102 resistance, 2181 OR circuit, 2183 AND circuit, 2185 OR circuit, 2200 computer, 2201 DVD-ROM, 2210 Host controller, 2212 CPU, 2214 RAM, 2216 graphic controller, 2218 display device, 2220 input / output controller, 2222 communication interface, 2224 hard disk drive, 2226 DVD-ROM drive, 2230 ROM, 2240 input / output chip, 2242 keyboard.

Claims (18)

It is a control device that controls a plurality of first power conversion devices that convert the power from the distributed power source into the power according to the system power supply.
For each of the plurality of first power converter, a line impedance of the connected power line in the local area where the first power converter is connected in the electric power system, of a device other than the first power converter and based on the local area information, adjustment determiner which determines the adjustment of the reactive power output characteristic to be used for the first power converter to detect the islanding state containing information about at least one,
Among the plurality of first power conversion devices, an adjustment instruction unit for instructing the first power conversion device whose adjustment has been determined to adjust the determined ineffective power output characteristic,
A control device equipped with. The amount of power used by the load connected in the local area, the amount of active power output by the second power conversion device connected in the local area, the line impedance of the wiring connected in the local area, and the local. The control device according to claim 1, further comprising a collecting unit that collects information about at least one of the power flow states at a point in the area as at least a part of the local area information. The control device according to claim 1 or 2, further comprising a demand forecasting unit that predicts the electric energy used or the change in the electric energy of the load connected in the local area and includes it in the local area information. Any one of claims 1 to 3 further comprising a supply prediction unit that predicts the amount of active power output by the second power conversion device connected in the local area or the change in the amount of active power and includes it in the local area information. The control device described in the section. The second power conversion device connected in the local area converts the power from the distributed power source that performs solar power generation into the power corresponding to the system power supply.
The control device according to claim 4, wherein the supply prediction unit predicts at least one of an active power amount and a change in the active power amount output by the second power conversion device based on the sunshine prediction. The adjustment determination unit further reduces the amount of ineffective power output by the first power conversion device in response to the increase in the amount of active power output by the second power conversion device connected in the local area. The control device according to any one of claims 1 to 5, which determines to adjust to the invalid power output characteristic. The adjustment determination unit has the disabled power output characteristic in which the amount of disabled power output by the first power conversion device is further increased in response to the increase in the amount of power used by the load connected in the local area. The control device according to any one of claims 1 to 6, which is determined to be adjusted. A simulation processing unit that performs power simulation using the model of the local area based on the local area information is further provided.
The control device according to any one of claims 1 to 7, wherein the adjustment determination unit determines adjustment of the reactive power output characteristic based on the result of the power simulation. It is a power conversion device that converts the power from the distributed power supply into the power according to the system power supply.
An ineffective power injection unit that injects an amount of ineffective power calculated using the ineffective power output characteristic for detecting the independent operation state of the power conversion device into the output power, and an ineffective power injection unit.
A switching unit capable of switching a single-phase alternating current to be selected from a plurality of single-phase alternating currents included in the multi-phase alternating current of the system power supply.
It is equipped with an output stop unit that stops the output from the distributed power source according to the result of observing the selected single-phase AC .
The reactive power injection unit, the power conversion device that adjust the reactive power output characteristics according to an instruction from another device. When the voltage on the system power supply side is lower than the reference value, the output stop unit can be used from the distributed power supply in response to the detection of a single operation state in any of the plurality of single-phase alternating currents. The power conversion device according to claim 9, wherein the output of the power conversion device is stopped. The output stop unit is
For each of the plurality of single-phase alternating currents, an independent operation detection unit that detects the independent operation state of the distributed power source, and
A voltage drop detection unit that detects a voltage drop state in which the voltage on the system power supply side drops below the reference value, and
The stop condition that the single-phase AC is detected in the selected single-phase AC, or that the single-phase AC is detected in any of the plurality of single-phase ACs and the voltage drop state is detected. The power conversion device according to claim 10, further comprising a condition determination unit for determining whether or not is satisfied. A control device for controlling the power conversion device according to any one of claims 9 to 11.
A control provided with a selection instruction unit for instructing two or more power conversion devices to select the same single-phase alternating current by the switching unit from the plurality of single-phase alternating currents included in the multi-phase alternating current. Device. Further, a selection information acquisition unit for acquiring selection information of the single-phase alternating current selected in each of the plurality of power conversion devices is provided.
12. The control device according to claim 12, wherein the selection instruction unit instructs another power conversion device to select the single-phase alternating current most selected among the plurality of power conversion devices. Further, a fixed state information acquisition unit for acquiring fixed state information indicating single-phase alternating current used by one power conversion device having no switching unit for determining a stop condition is provided.
The selection indicating unit instructs the two or more power conversion devices to select the same single-phase alternating current as the single-phase alternating current shown in the fixed state information by the switching unit, claim 12 or 13. The control device described in. It is a control method for controlling a plurality of first power conversion devices that convert the power from the distributed power source into the power according to the system power supply.
For each of the plurality of first power converter, a line impedance of the connected power line in the local area where the first power converter is connected in the electric power system, of a device other than the first power converter an adjustment decision step based on the local area information, to determine the adjustment of the reactive power output characteristic to be used for the first power converter to detect the islanding state containing information about at least one,
Among the plurality of first power conversion devices, an adjustment instruction step for instructing the first power conversion device whose adjustment has been determined to adjust the determined ineffective power output characteristics, and
A control method that comprises. A computer that controls a plurality of first power converters that convert the power from each distributed power source into the power according to the system power supply.
For each of the plurality of first power converter, a line impedance of the connected power line in the local area where the first power converter is connected in the electric power system, of a device other than the first power converter and based on the local area information, adjustment determiner which determines the adjustment of the reactive power output characteristic to be used for the first power converter to detect the islanding state containing information about at least one,
Of the plurality of first power conversion devices, an adjustment instruction unit that instructs the first power conversion device whose adjustment has been determined to adjust the determined ineffective power output characteristic.
A program that functions as. It is a power conversion method that is executed in a power conversion device and converts the power from a distributed power source into the power according to the system power supply.
An ineffective power injection stage in which an amount of ineffective power calculated using the ineffective power output characteristic for detecting the independent operation state of the power conversion device is injected into the output power, and
A switching stage for switching a single-phase alternating current to be selected from a plurality of single-phase alternating currents included in the multi-phase alternating current of the system power supply.
It is provided with an output stop stage in which the output from the distributed power source is stopped according to the result of observing the selected single-phase AC .
Wherein in the reactive power injection stage power conversion how to adjust the reactive power output characteristics according to an instruction from another device. A computer with a power converter that converts power from a distributed power source into power according to the system power supply.
An ineffective power injection unit that injects an amount of ineffective power calculated using the ineffective power output characteristic for detecting the independent operation state of the power conversion device into the output power, and an ineffective power injection unit.
A switching unit capable of switching a single-phase alternating current to be selected from a plurality of single-phase alternating currents included in the multi-phase alternating current of the system power supply.
Depending on the result of observing the selected single-phase AC, it functions as an output stop unit that stops the output from the distributed power source .
The reactive power injection unit program that adjusts the reactive power output characteristics according to an instruction from another device.

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