CN113258609A - Grid-connected power control method and application system thereof - Google Patents
Grid-connected power control method and application system thereof Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The invention provides a grid-connected power control method and an application system thereof, which are applied to the technical field of power supply. In the control method provided by the invention, the current output power of the power subarray is acquired by the acquisition module connected with the power subarray, a mode of polling each inverter in the prior art is not adopted any more, and further the problems of inconsistent output power acquisition time and main line competition when data is fed back caused by the inconsistent output power acquisition time and main line competition are avoided.
Description
Technical Field
The invention relates to the technical field of power supply, in particular to a grid-connected power control method and an application system thereof.
Background
In the existing application, a large-scale new energy power supply system mostly adopts a mode of block power supply and centralized grid connection, taking a photovoltaic power station as an example, the system is generally divided into a photovoltaic sub-array every 1 megawatt, a photovoltaic module, a junction box, an inverter and a sub-array transformer connected with the inverter are configured in the photovoltaic sub-array, and after the inverter completes the direct current-alternating current electric energy conversion, the voltage is preliminarily boosted by the sub-array transformer. Furthermore, a plurality of photovoltaic sub-arrays in the photovoltaic power station are concentrated into one path, and finally the photovoltaic sub-arrays are boosted by the grid-connected transformer and then are merged into the alternating current power grid.
In order to control grid-connected power, namely output power, of each photovoltaic subarray, a subarray controller is arranged in an existing photovoltaic subarray, the subarray controller is in communication connection with each inverter in the photovoltaic subarray, the output power of each inverter is obtained in a polling mode, the output power of the photovoltaic subarray is further obtained, and the photovoltaic subarray is controlled according to the output power of the photovoltaic subarray and target power included in an obtained power scheduling instruction.
However, the subarray controller acquires the grid-connected power of each inverter in a polling manner, so that a time difference exists between the acquired grid-connected powers of the plurality of inverters, the control accuracy of the grid-connected power is low, and meanwhile, the response speed of the power scheduling command is influenced due to main line competition among the inverters.
Disclosure of Invention
The invention provides a grid-connected power control method and an application system thereof, wherein the current output power of a power subarray in the grid-connected control process is acquired by an acquisition module, and a polling inverter mode is not adopted any more, so that the problems of time difference and main line competition when the output power of an inverter is acquired in the prior art are solved, and the precision and the response speed of grid-connected power control are improved.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
in a first aspect, the present invention provides a grid-connected power control method, including:
acquiring a power scheduling instruction, wherein the power scheduling instruction comprises a target output power of a power subarray;
responding to the power scheduling instruction, and acquiring the current output power of the power subarray;
the current output power is acquired by an acquisition module connected with the power subarray;
and adjusting the output power of the power subarray according to the magnitude relation between the current output power and the target output power.
Optionally, the adjusting the output power of the power sub-array according to the magnitude relationship between the current output power and the target output power includes:
if the current output power is not equal to the target output power, detecting the communication state of each inverter in the power sub-array;
and adjusting the output power of the power sub-array to the target output power according to the detection result.
Optionally, the adjusting the output power of the power sub-array to the target output power according to the detection result includes:
if the communication with each inverter in the power subarray is normal, a power adjusting instruction is sent to each inverter respectively, so that each inverter adjusts the output power of the inverter according to the corresponding power adjusting instruction until the sum of the output power of each inverter reaches the target output power.
Optionally, if communication with each inverter in the power sub-array is abnormal, the neutral-point-to-ground voltage of the sub-array transformer in the power sub-array is adjusted, so that each inverter adjusts its output power according to a preset corresponding relationship between the neutral-point-to-ground voltage and the output power until the sum of the output powers of each inverter reaches the target output power.
Optionally, the sending a power adjustment command to each of the inverters respectively includes:
acquiring a preset output proportion corresponding to each inverter, wherein the preset output proportion is determined based on the rated power of each inverter;
for each inverter, determining a target power value of the inverter according to a preset output proportion corresponding to the inverter and the target output power;
generating a power adjustment command corresponding to each of the inverters based on each of the target power values;
and respectively sending corresponding power regulation commands to the inverters.
Optionally, the neutral point of the sub-array transformer is grounded through the voltage regulation module;
the adjusting the neutral point of the sub-array transformer in the power sub-array to the ground voltage comprises:
determining a target voltage according to a proportionality coefficient between the target output power and the rated power of the power subarray;
and adjusting the output voltage of the voltage adjusting module to the target voltage.
Optionally, the determining a target voltage according to a proportionality coefficient between the target output power and a rated power of the power sub-array includes:
calling a preset mapping relation, wherein the preset mapping relation records a corresponding relation between a proportional coefficient between the output power of the power subarray and the rated power of the power subarray and the output voltage of the voltage regulating module;
and inquiring the preset mapping relation, and determining a target voltage corresponding to a proportionality coefficient between the target output power and the rated power of the power subarray.
Optionally, if the current output power is equal to the target output power, the current output power of the power sub-array is maintained.
Optionally, the obtaining the current output power of the power sub-array includes:
acquiring the current voltage and current of the parallel connection point of each inverter acquired by the acquisition module;
and determining the current output power of the power sub-array according to the current voltage and the current.
In a second aspect, the present invention provides a grid-connected power control apparatus, including: an acquisition module, a voltage regulation module and a subarray controller, wherein,
the acquisition module acquires the current output power of the power subarray;
the voltage regulating module is connected between a neutral point of a sub-array transformer in the power sub-array and the ground;
the subarray controller is connected with the acquisition module and the voltage regulation module respectively, and executes the grid-connected power control method of any one of the first aspect of the invention.
Optionally, the acquisition module is connected between the parallel connection point of each inverter in the power sub-array and the sub-array transformer.
In a third aspect, the present invention provides an energy storage power station comprising: at least one energy storage sub-array and a grid-connected transformer, wherein,
each energy storage sub-array is connected with the primary side of the grid-connected transformer;
the secondary side of the grid-connected transformer is connected with an alternating current power grid;
the energy storage sub-array comprises the grid-connected power control device of the second aspect of the invention.
In a fourth aspect, the present invention provides a photovoltaic power plant comprising: at least one photovoltaic sub-array and a grid-connected transformer, wherein,
each photovoltaic subarray is connected with the primary side of the grid-connected transformer;
the secondary side of the grid-connected transformer is connected with an alternating current power grid;
the photovoltaic sub-array comprises the grid-connected power control device of the second aspect of the invention.
According to the grid-connected power control method provided by the invention, after the power scheduling instruction comprising the target output power of the power subarray is obtained, the current output power of the power subarray is obtained, and the output power of the power subarray is adjusted according to the size relation between the obtained current output power and the target output power. In the control method provided by the invention, the current output power of the power subarray is acquired by the acquisition module connected with the power subarray, a mode of polling each inverter in the prior art is not adopted any more, and further the problems of inconsistent output power acquisition time and main line competition when data is fed back caused by the inconsistent output power acquisition time and main line competition are avoided.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a grid-connected power control method according to an embodiment of the present invention;
fig. 2 is a flowchart of another grid-connected power control method according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a grid-connected power control device according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a photovoltaic power plant provided by an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an energy storage power station according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The invention provides a grid-connected power control method, which can be applied to a subarray controller of each power subarray in a new energy system, can also be applied to other controllers which can control the working process of the power subarray in the new energy system, and can also be applied to a server on a network side under certain conditions.
Referring to fig. 1, fig. 1 is a flowchart of a grid-connected power control method according to an embodiment of the present invention, where the flowchart of the grid-connected power control method according to the embodiment may include:
s100, acquiring a power scheduling instruction.
In practical application, electric power output by the new energy system to the alternating current power grid in a grid-connected state is flexibly adjusted according to currently available power of the new energy system and required power of the alternating current power grid, and correspondingly, output power of each power sub-array is changed according to requirements particularly in the new energy system. The power scheduling instruction sent by the upper computer is received by the subarray controller, and the power scheduling instruction comprises the target output power of the power subarray corresponding to the subarray controller. It is conceivable that, if the new energy system includes a plurality of power sub-arrays, a plurality of sub-array controllers are often required to be arranged, target output powers included in the power scheduling instructions received by the respective sub-array controllers may be the same or different, and after receiving the power scheduling instruction of each sub-array controller, any sub-array controller may control the corresponding power sub-array to operate according to the obtained power scheduling instruction.
It should be noted that, a specific source of the power scheduling instruction, or a specific selection of the foregoing upper computer, may be implemented based on the prior art, and the present invention is not limited thereto.
And S110, responding to the power scheduling instruction, and acquiring the current output power of the power subarray.
After the power scheduling instruction is received, the obtained power scheduling instruction can be responded, and the current output power of the power subarray is obtained.
In the prior art, the process of obtaining the current output power of the power subarray severely limits the efficiency of the whole grid-connected power control process. As can be seen from the basic structure of the new energy system, most of the power sub-arrays include a plurality of inverters, the dc side of each inverter is connected to a dc power supply for providing dc power, and the ac sides of the inverters are connected in parallel, and the inverters convert the dc power output from the dc power supply connected to the inverter into ac power, so that the sum of the current output powers of the inverters, i.e., the current output power of the power sub-array. In the prior art, a subarray controller is in communication connection with each inverter, and the current output power of each inverter is sequentially obtained in a polling manner, so that the current output power of a power subarray is obtained through calculation.
Due to the fact that the inverters need to be acquired one by one, the acquisition time corresponding to the current output power of each inverter is different, namely, time difference exists, the control accuracy of grid-connected power is low inevitably, and meanwhile, the response speed of the power scheduling instruction is influenced due to main line competition among the inverters.
In order to solve the problem, the current output power of the power sub-array is directly acquired by the acquisition module connected with the power sub-array, and it is emphasized that the current output power of the power sub-array is directly acquired by the method, and is not the current output power of each inverter in the power sub-array.
As an optional implementation manner, the acquisition module may be disposed between the ac-side parallel connection point of each inverter and the subarray transformer, so as to directly acquire the overall power of the power subarray. For this setting, it will be expanded in the following, and will not be described in detail here.
Optionally, for specific implementation, the acquisition module may directly feed back the current output power of the power sub-array to the sub-array controller, or may feed back the current voltage and current of the parallel connection point of each of the modulators in the power sub-array to the sub-array controller, and the sub-array controller further determines the current output power of the power sub-array according to the obtained current voltage and current.
And S120, adjusting the output power of the power subarray according to the magnitude relation between the current output power and the target output power.
After the current output power and the target output power of the power subarray are obtained through the steps, the output power of the power subarray can be adjusted according to the size relation of the current output power and the target output power until the actual output power of the power subarray reaches the target output power.
In summary, in the control method provided by the present invention, the current output power of the power sub-array is acquired by the acquisition module connected to the power sub-array, and a manner of polling each inverter in the prior art is no longer adopted, so that the problems of inconsistent output power acquisition time and main line competition when feeding back data caused by the inconsistent output power acquisition time and main line competition do not exist.
Optionally, referring to fig. 2, the figure is a flowchart of another grid-connected power control method provided in an embodiment of the present invention, and on the basis of the embodiment shown in fig. 1, a more specific grid-connected power control method is provided in this embodiment, and the flowchart of the method may include:
s200, acquiring a power scheduling instruction.
Optionally, an optional implementation manner of S200 may be performed with reference to S100 in the embodiment shown in fig. 1, and details are not described here.
S210, responding to the power scheduling instruction, and acquiring the current output power of the power subarray.
Optionally, an optional implementation manner of S210 may be performed with reference to S110 in the embodiment shown in fig. 1, and details are not described here.
S220, judging whether the current output power is equal to the target output power, if not, executing S230, and if so, executing S250.
The target output power included in the power scheduling instruction is a target value of the output power of the power subarray, and the final target of the parallel power control process is to enable the output power of the power subarray to reach the target output power, so that after the current output power and the target output power of the power subarray are obtained, whether the current output power and the target output power are equal or not is judged, and a subsequent control process is further determined.
And S230, detecting the communication state of each inverter in the power sub-array.
As described above, the sub-array controller is in communication connection with each inverter in the power sub-array, and the control method provided in this embodiment improves the manner of obtaining the current output power of the power sub-array, but still maintains the communication connection relationship in the prior art with each inverter.
Based on this, for the detection of the communication state with each inverter, the detection can be realized by combining the communication detection method in the prior art based on the specific selection of the communication network, and the present invention is not limited to this.
And S240, adjusting the output power of the power sub-array to the target output power according to the detection result.
Based on the foregoing, the sum of the output powers of the inverters in the power sub-array is the output power of the power sub-array, and therefore, in a specific control process, the output power of each inverter in the power sub-array needs to be adjusted until the sum of the output powers of the inverters reaches the target output power.
The communication states of the subarray controller and each inverter of the grid-connected power control method provided by the embodiment of the invention comprise normal and abnormal conditions, and different adjustment methods are required to be adopted under different communication detection results. The specific detection result can still be obtained based on the prior art, and the present invention is not limited to this.
Specifically, under the condition that the communication between the subarray controller and each inverter in the power subarray is normal, the subarray controller sends a power adjustment instruction to each inverter, and of course, each power adjustment instruction includes a target power value of the corresponding inverter, so that each inverter adjusts its output power according to the obtained power adjustment instruction after obtaining the power adjustment instruction sent to itself.
In practical applications, the rated power of each inverter in the power sub-array may be the same or different. Under the condition that the rated power of each inverter is the same, the quotient of the target output power and the number of the inverters included in the power subarray can be used as the target power value of each inverter, so that each inverter can share the target output power on average.
Further, under the condition that the rated powers of the inverters are not identical, the preset output proportion of each inverter can be determined in advance according to the rated power of each inverter, when the target power value of each inverter is determined, the preset output proportion corresponding to each inverter is obtained, and then the product of the preset output proportion corresponding to each inverter and the target output power is calculated for each inverter, so that the target power value corresponding to each inverter is determined.
After the target power values of the inverters are obtained, power adjustment commands corresponding to the inverters are generated based on the target power values, and the corresponding power adjustment commands can be sent to the inverters.
It should be noted that other manners may also be adopted to determine the target power value of each inverter, which are not listed here, and the present invention also falls within the protection scope of the present invention without departing from the scope of the core idea of the present invention.
Furthermore, under the condition that the communication between the sub-array controller and each inverter is abnormal, a voltage regulating module can be preset between the neutral point of the sub-array transformer of the power sub-array and the ground, the purpose of regulating the neutral point-to-ground voltage of the sub-array transformer is achieved by regulating the output voltage of the voltage regulating module, and then each inverter can regulate the output power of the inverter according to the preset corresponding relation between the neutral point-to-ground voltage and the output power.
Specifically, the target voltage is determined according to a proportionality coefficient between the target output power and the rated power of the power sub-array. For example, the target output power is 100kW, the rated power of the power sub-array is 200kW, and the proportionality coefficient of the power sub-array and the power sub-array is 50%, after the proportionality coefficient is obtained, a preset mapping relation is called, a corresponding relation between the proportionality coefficient between the output power of the power sub-array and the rated power of the power sub-array and the output voltage of the voltage regulating module is recorded in the preset mapping relation, by inquiring the preset mapping relation, the target voltage corresponding to the proportionality coefficient between the target output power and the rated power of the power sub-array in the current control process can be determined, the output voltage of the voltage regulating module is regulated to the target voltage, and therefore the neutral point of the sub-array transformer is regulated to the ground voltage.
Each inverter can adjust the output power of the inverter according to the collected neutral point-to-ground voltage and the preset corresponding relation between the neutral point-to-ground voltage and the output power until the sum of the output power of each power inverter is equal to the target output power.
It should be noted that, for each inverter in the power sub-array, first, it also has a function of detecting a communication state with the sub-array controller, and accordingly, in a case where the communication is normal, the output power of the inverter is adjusted based on the received power adjustment command, and in a case where the communication is abnormal, the output power of the inverter is adjusted based on the neutral-point ground voltage obtained by the acquisition.
In addition, each inverter also stores a corresponding relationship between the neutral point-to-ground voltage and the output power, which corresponds to its rated power, that is, in order to avoid overload operation of each inverter, the corresponding relationship between the neutral point-to-ground voltage and the output power stored in each inverter may be different, and after acquiring the neutral point-to-ground voltage, each inverter needs to check the corresponding target power value in combination with its pre-stored corresponding relationship.
Of course, the above description of the inverter function can be implemented based on the prior art, and the present invention is not limited thereto.
It is conceivable that, regardless of the power regulation method, the final target of the regulation is such that the sum of the output powers of the inverters reaches the aforementioned target output power.
And S250, maintaining the current output power of the power subarray.
And maintaining the current output power of the power subarray under the condition that the current output power of the power subarray is equal to the target output power.
In summary, on the basis of the embodiment shown in fig. 1, the grid-connected power control method provided in this embodiment can select different power regulation modes according to the communication state between the subarray controller and the inverter, has a wider application range, and is beneficial to stable operation of a new energy system.
It should be noted that, in the prior art, a PID control method is also adopted for the output power of the inverter in the power sub-array, and when the communication between the sub-array controller provided by the present invention and the inverter is abnormal, the control method for adjusting the voltage of the voltage-variable neutral point of the sub-array to the ground voltage has a certain conflict with the execution process of the PID control method, so that when the method provided by the present invention is adopted, the PID function in the inverter needs to be shut down, and the two can not be executed at the same time.
Optionally, referring to fig. 3, fig. 3 is a block diagram of a structure of a grid-connected power control device according to an embodiment of the present invention, where the grid-connected power control device according to the embodiment includes: an acquisition module 10, a voltage regulation module 20, and a subarray controller 30, wherein,
the dc side of each inverter 50 is connected to a corresponding dc power source (not shown), the ac side of each inverter 50 is connected in parallel, and the acquisition module 10 is connected between the parallel connection point of each inverter 50 and the sub-array transformer 40. The current output power of the power sub-array is collected by the collection module 10, of course, the collection module 10 may also collect the current voltage and current of the power sub-array, and the calculation process of the current output power is realized by the sub-array controller 30.
The voltage regulating module 20 is connected between the neutral point of the sub-array transformer 40 in the power sub-array and the ground, and the neutral point of the sub-array transformer 40 can be regulated to the ground voltage by controlling the output voltage of the voltage regulating module 20.
It should be noted that, for the specific implementation of the acquisition module 10 and the voltage regulation module 20, the implementation may be implemented by combining the prior art, and details are not described here.
The subarray controller 30 is connected to the acquisition module 10 and the voltage regulation module 20, respectively, and executes the grid-connected power control method provided in any of the above embodiments.
Optionally, referring to fig. 4, fig. 4 is a schematic structural diagram of a photovoltaic power station provided in an embodiment of the present invention, where the photovoltaic power station provided in this embodiment includes: at least one photovoltaic sub-array (shown in two in fig. 4) and a grid-tie transformer, wherein,
each photovoltaic sub-array is connected with the primary side of the grid-connected transformer respectively;
the secondary side of the grid-connected transformer is connected with an alternating current power grid;
the photovoltaic subarray comprises the grid-connected power control device provided by any one of the embodiments.
Optionally, referring to fig. 5, fig. 5 is a schematic structural diagram of an energy storage power station provided in an embodiment of the present invention, where the energy storage power station provided in this embodiment includes: at least one energy storage sub-array (shown in fig. 5 in two) and a grid-tie transformer, wherein,
each energy storage sub-array is connected with the primary side of the grid-connected transformer respectively;
the secondary side of the grid-connected transformer is connected with an alternating current power grid;
the energy storage sub-array comprises the grid-connected power control device provided by any one of the embodiments.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (13)
1. A grid-connected power control method is characterized by comprising the following steps:
acquiring a power scheduling instruction, wherein the power scheduling instruction comprises a target output power of a power subarray;
responding to the power scheduling instruction, and acquiring the current output power of the power subarray;
the current output power is acquired by an acquisition module connected with the power subarray;
and adjusting the output power of the power subarray according to the magnitude relation between the current output power and the target output power.
2. The grid-connected power control method according to claim 1, wherein the adjusting the output power of the power sub-array according to the magnitude relation between the current output power and the target output power comprises:
if the current output power is not equal to the target output power, detecting the communication state of each inverter in the power sub-array;
and adjusting the output power of the power sub-array to the target output power according to the detection result.
3. The grid-connected power control method according to claim 2, wherein the adjusting the output power of the power sub-array to the target output power according to the detection result comprises:
if the communication with each inverter in the power subarray is normal, a power adjusting instruction is sent to each inverter respectively, so that each inverter adjusts the output power of the inverter according to the corresponding power adjusting instruction until the sum of the output power of each inverter reaches the target output power.
4. The grid-connected power control method according to claim 2, wherein if communication with each inverter in the power sub-array is abnormal, the neutral-point to ground voltage of the sub-array transformer in the power sub-array is adjusted, so that each inverter adjusts its own output power according to a preset correspondence between the neutral-point to ground voltage and the output power until the sum of the output powers of each inverter reaches the target output power.
5. The grid-connected power control method according to claim 3, wherein the sending of the power adjustment command to each of the inverters, respectively, includes:
acquiring a preset output proportion corresponding to each inverter, wherein the preset output proportion is determined based on the rated power of each inverter;
for each inverter, determining a target power value of the inverter according to a preset output proportion corresponding to the inverter and the target output power;
generating a power adjustment command corresponding to each of the inverters based on each of the target power values;
and respectively sending corresponding power regulation commands to the inverters.
6. The grid-connected power control method according to claim 4, wherein a neutral point of the subarray transformer is grounded through a voltage regulation module;
the adjusting the neutral point of the sub-array transformer in the power sub-array to the ground voltage comprises:
determining a target voltage according to a proportionality coefficient between the target output power and the rated power of the power subarray;
and adjusting the output voltage of the voltage adjusting module to the target voltage.
7. The grid-connected power control method according to claim 6, wherein the determining a target voltage according to a proportionality coefficient between the target output power and a rated power of the power sub-array comprises:
calling a preset mapping relation, wherein the preset mapping relation records a corresponding relation between a proportional coefficient between the output power of the power subarray and the rated power of the power subarray and the output voltage of the voltage regulating module;
and inquiring the preset mapping relation, and determining a target voltage corresponding to a proportionality coefficient between the target output power and the rated power of the power subarray.
8. The grid-connected power control method according to claim 2, wherein if the current output power is equal to the target output power, the current output power of the power sub-array is maintained.
9. The grid-connected power control method according to any one of claims 1 to 8, wherein the obtaining of the current output power of the power sub-array comprises:
acquiring the current voltage and current of the parallel connection point of each inverter acquired by the acquisition module;
and determining the current output power of the power sub-array according to the current voltage and the current.
10. A grid-connected power control device, comprising: an acquisition module, a voltage regulation module and a subarray controller, wherein,
the acquisition module acquires the current output power of the power subarray;
the voltage regulating module is connected between a neutral point of a sub-array transformer in the power sub-array and the ground;
the subarray controller is respectively connected with the acquisition module and the voltage regulation module, and executes the grid-connected power control method according to any one of claims 1 to 9.
11. The grid-connected power control device according to claim 10, wherein the collection module is connected between a parallel connection point of each inverter in the power sub-array and the sub-array transformer.
12. An energy storage power plant, comprising: at least one energy storage sub-array and a grid-connected transformer, wherein,
each energy storage sub-array is connected with the primary side of the grid-connected transformer;
the secondary side of the grid-connected transformer is connected with an alternating current power grid;
the energy storage sub-array comprises the grid-connected power control device of any one of claims 10-11.
13. A photovoltaic power plant, comprising: at least one photovoltaic sub-array and a grid-connected transformer, wherein,
each photovoltaic subarray is connected with the primary side of the grid-connected transformer;
the secondary side of the grid-connected transformer is connected with an alternating current power grid;
the photovoltaic sub-array comprises the grid-connected power control device of any one of claims 10-11.
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