A photovoltaic low voltage ride-through configuration method and system adapted to load

Abstract

The present invention relates to a method and system for configuring photovoltaic low voltage ride-through that is adaptive to loads, and to the technical field of photovoltaic low voltage ride-through. The present application sets the expected load power, the initial value and the minimum value of the low voltage ride-through limit of each photovoltaic system; checks whether the generator can meet the expected load power when the photovoltaic system is normally disconnected from the grid while the power grid maintains the expected load power under the current low voltage ride-through limit conditions. If so, the photovoltaic system is normally disconnected from the grid; if not, then: all photovoltaic systems that are disconnected from the grid and expected to be disconnected from the grid are used as candidates for adjusting the photovoltaic low voltage ride-through configuration; under the stability constraint of meeting the expected load power, within the range of the initial value and the minimum value of the low voltage ride-through limit, determine the planning space; select a solution with a power greater than the expected load as a candidate solution from the planning space according to the relationship formula between the photovoltaic access state and the load, and take the candidate solution that minimizes the low voltage ride-through limit.

Description

Technical Field

[0001] The present invention relates to the technical field of low voltage ride-through performance detection, and in particular to a load-adaptive photovoltaic low voltage ride-through configuration method and system. Background Art

[0002] The photovoltaic system is networked through inverters. In order to enhance the stability of the network, a low voltage ride-through control strategy is set for the photovoltaic system. Under the control of the low voltage ride-through control strategy, when the voltage at the grid connection point drops due to a grid fault or load change, the photovoltaic system can ensure continuous operation without disconnection within a certain voltage drop range and time interval. The general low voltage ride-through control strategy follows the low voltage ride-through curve.

[0003] In the actual operation of the power grid, the user load is provided by the photovoltaic system and the generator. When the photovoltaic system is disconnected from the grid, the generator often needs to supply more power to meet the demand; however, the useful power output of the generator has an upper limit. When the generator power supply reaches the limit, if the load power of the power grid cannot meet the user load, it is necessary to limit the power supply to the user, affecting the normal production and life of the user. The low voltage ride-through curve has a certain degree of flexibility, that is, within a certain range, it supports the adjustment of the voltage amplitude of the low voltage ride-through curve. By reducing the voltage amplitude of the low voltage ride-through curve, the photovoltaic system that was originally disconnected from the grid continues to cooperate with the generator to supply power, and the load power of the power grid can be increased accordingly to meet the user load. To achieve this adjustment, there are many difficulties. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present invention provides a load-adaptive photovoltaic low voltage ride-through configuration method and system.

[0005] In a first aspect, the present invention provides a method for configuring a photovoltaic low voltage ride-through system that is adapted to a load, comprising:

[0006] Pre-set the expected load power that can meet user needs , the initial value and minimum value of the low voltage ride-through limit in the low voltage ride-through curve of each PV system;

[0007] Verify that the PV system maintains the expected load power under the current low voltage ride-through limit conditions When the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? If yes, the PV system is disconnected from the grid normally; if no, then:

[0008] The photovoltaic systems that are completely disconnected and expected to be disconnected are taken as candidates for adjusting the low voltage ride-through configuration, and the low voltage ride-through configuration of the remaining photovoltaic systems remains unchanged; the power flow state dynamic equation that introduces the photovoltaic access state is used to determine the load power that meets the expected load Stability constraints; when satisfying the expected load power Under the control of the stability constraint, the planning space is determined within the range of the initial value and the minimum value of the low voltage ride-through limit; the relationship formula between the photovoltaic access state and the load is determined according to the influence of each photovoltaic system access state on the grid load, and a value greater than the expected load power is taken from the planning space according to the relationship formula between the photovoltaic access state and the load. The scheme is taken as a candidate scheme, and the candidate scheme is optimized with the goal of minimizing the change in the low voltage ride-through limit of the entire PV system.

[0009] Furthermore, a mapping table of the minimum value of the low voltage ride-through limit with regional, time and climate changes is constructed. During operation, the minimum value of the low voltage ride-through limit is matched from the mapping table according to the region, time and regional climate conditions of the photovoltaic system. For any photovoltaic system, the minimum value of the low voltage ride-through limit under any regional, time and climate change conditions is less than the initial value of the low voltage ride-through limit.

[0010] Furthermore, the PV system is tested to ensure that the grid maintains the expected load power under the current low voltage ride-through limit conditions. When the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? include:

[0011] Get the current low voltage ride-through limit and PV curve for each PV system;

[0012] Based on expected load power Find the expected voltage value for each PV system in the grid from the PV curve of each PV system ; Based on the expected voltage value The current low voltage ride-through limit is used to determine whether each PV system violates the low voltage ride-through limit, and a simulation is performed to calculate whether the generator power can meet the expected voltage value after the PV system that violates the low voltage ride-through limit is disconnected from the grid.

[0013] Furthermore, the dynamic equation form of the power flow state of the power grid is constructed by considering the load change state and the photovoltaic system access state: ;

[0014] is the access state matrix of the photovoltaic system, Discrete state variables belonging to the dynamic equation of the power flow state; access state matrix of the photovoltaic system The element in the matrix is ​​1 or 0, and is connected to the state matrix The element 1 indicates that the corresponding photovoltaic system is connected to the grid, and the access state matrix The middle element is 0, indicating that the corresponding PV system is off-grid;

[0015] is the voltage amplitude of all grid nodes and phase angle ;

[0016] is the load change state. The elements in the load change state are -1 or 1, which are used to control the load change direction. is the load scaling factor, which is used to control the load change ratio;

[0017] Functions that represent the internal relationships of state variables, is a function of the derivative of the continuous state variable under any photovoltaic access state.

[0018] Furthermore, the desired load power is achieved The corresponding load scaling factor is , considering the discrete photovoltaic system access state, then To meet the expected load power stability constraints.

[0019] Furthermore, based on the expected load power Find the expected voltage value for each PV system in the grid from the PV curve of each PV system ; For the candidate objects, set the low voltage ride-through limit of any PV system combination in the candidate objects to the expected voltage value Get several plans to use as planning space.

[0020] Furthermore, the relationship between the photovoltaic access state and the load is determined according to the influence of each photovoltaic system access state on the grid load:

[0021] ,

[0022] in, is the impact of photovoltaic access status on load, For the candidate solution, it is the change of the candidate solution relative to the total disconnection of the candidate object. is the load scaling factor corresponding to when all candidate objects are offline, is the load scaling factor of the solution in the corresponding planning space.

[0023] Furthermore, When the power grid is stable, considering the discrete photovoltaic system access state, then When the power grid is stable, the process of solving the influence of each photovoltaic system access state on the grid load includes: when the generator is in the limit state, the stability constraint Differentiate to get:

[0024] ;

[0025] based on and The relationship between them determines the impact of the photovoltaic system access status on the grid load include:

[0026] set up ,but:

[0027] ,

[0028] ;

[0029] The relationship between photovoltaic access status and load is determined according to the influence of each photovoltaic system access status on the grid load:

[0030] .

[0031] In a second aspect, the present invention provides a load-adaptive photovoltaic low voltage ride-through configuration device, comprising: at least one processing unit, the processing unit is connected to a storage unit and a collection unit through a bus unit, the collection unit collects parameters required for a load-adaptive photovoltaic low voltage ride-through configuration method from each photovoltaic system and generator, the storage unit stores a computer program, and when the computer program is executed by the processing unit, the load-adaptive photovoltaic low voltage ride-through configuration method is implemented.

[0032] In a third aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for configuring a load-adaptive photovoltaic low voltage ride-through is implemented.

[0033] The above technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0034] The present application proposes a method for configuring photovoltaic low voltage ride-through that is adaptive to loads. The present application sets the expected load power, the initial value and the minimum value of the low voltage ride-through limit of each photovoltaic system; checks whether the generator can meet the expected load power when the photovoltaic system is normally disconnected from the grid while the power grid maintains the expected load power under the current low voltage ride-through limit conditions. If so, the photovoltaic system is normally disconnected from the grid; if not, then: all photovoltaic systems that are disconnected from the grid and expected to be disconnected from the grid are used as candidates for adjusting the photovoltaic low voltage ride-through configuration; under the stable constraint of meeting the expected load power, within the range of the initial value and the minimum value of the low voltage ride-through limit, determine the planning space; select a solution with a power greater than the expected load as a candidate solution from the planning space according to the relationship formula between the photovoltaic access state and the load, and take the candidate solution that minimizes the low voltage ride-through limit. The present invention supports dynamically reducing the photovoltaic low voltage ride-through configuration so that the photovoltaic system that was originally disconnected from the grid continues to cooperate with the generator for power supply, which can correspondingly increase the load power of the power grid to meet the user load. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 A flow chart of a method for configuring a photovoltaic low voltage ride-through adapted to a load provided by an embodiment of the present invention;

[0038] Figure 2 The embodiment of the present invention provides a method for checking whether the photovoltaic system maintains the expected load power under the current low voltage ride-through limit condition. , and when the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? Flowchart of

[0039] Figure 3 The influence of each photovoltaic system access state on the grid load provided in the embodiment of the present invention is used to determine the relationship formula between the photovoltaic access state and the load, and a power greater than the expected load power is taken from the planning space according to the relationship formula between the photovoltaic access state and the load. The scheme is a flow chart of candidate solutions;

[0040] Figure 4 A schematic diagram of a load-adaptive photovoltaic low voltage ride-through configuration device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0043] Example 1

[0044] like Figure 1 As shown, the technology of the present invention realizes a photovoltaic low voltage ride-through configuration method that adapts to loads, including:

[0045] Pre-set the expected load power that can meet user needs , then the expected load power is achieved The corresponding load scaling factor is .

[0046] Preset the initial and minimum value of the low voltage ride-through limit for each PV system.

[0047] In the specific implementation process, a mapping table of the minimum value of the low voltage ride-through limit with the regional, time, and climate changes is constructed. During the operation of the power grid, the minimum value of the low voltage ride-through limit is matched from the mapping table according to the region, time, and climate conditions of the photovoltaic system. For any photovoltaic system, the minimum value of the low voltage ride-through limit under any regional, time, and climate change conditions is less than the initial value of the low voltage ride-through limit. That is, the current low voltage ride-through limit of the photovoltaic system is between the initial value and the minimum value of the low voltage ride-through limit.

[0048] Verify that the PV system maintains the expected load power under the current low voltage ride-through limit conditions When the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? ,like Figure 2 As shown, the specific process includes:

[0049] Get the current low voltage ride-through limit and PV curve for each PV system;

[0050] Based on expected load power Find the expected voltage value for each PV system in the grid from the PV curve of each PV system ; Based on the expected voltage value The current low voltage ride-through limit is used to determine whether each PV system violates the low voltage ride-through limit. If yes, the PV system violating the low voltage ride-through limit is simulated to be disconnected from the grid. The simulation is used to calculate whether the generator power can meet the expected voltage value after the PV system violating the low voltage ride-through limit is disconnected from the grid.

[0051] If yes, the PV system is disconnected from the grid normally.

[0052] If not, then: all PV systems that are disconnected from the grid and expected to be disconnected from the grid are taken as candidates for adjusting the low voltage ride-through configuration, and the low voltage ride-through configuration of the remaining PV systems remains unchanged.

[0053] The power flow state dynamic equation with the photovoltaic access state is used to determine the power that meets the expected load stability constraints.

[0054] In the specific implementation process, whether the photovoltaic system is connected to the grid affects the structure of the grid. The access of the photovoltaic system is discrete. For the power flow of the grid, the discrete access of the photovoltaic system directly affects the dynamic equation of the power flow state. Therefore, the access state matrix of the photovoltaic system is introduced. As the discrete state variable of the dynamic equation of power flow state; the access state matrix of the photovoltaic system The element in the matrix is ​​1 or 0. The value is determined by the current low voltage ride-through configuration of the photovoltaic system and the grid connection point voltage. The element 1 indicates that the corresponding photovoltaic system is connected to the grid, and the access state matrix The value of 0 in the middle element indicates that the corresponding PV system is off-grid.

[0055] The magnitude of the grid node voltage and phase angle Directly affects the power flow, therefore, the amplitude of the grid node voltage and phase angle As the state variable of the dynamic equation of power flow; the amplitude of the voltage of all power grid nodes and phase angle Expressed as . Assuming the number of nodes is N, then The dimension is 2N, where the odd dimensions record the amplitude of the node , the phase angle of the even-dimensional recording node , .

[0056] Considering that the power flow needs to meet the load changes of all load nodes in the power grid; therefore, the load change state is introduced and load scaling factor To express the load change, the elements in the load change state are -1 or 1, which are used to control the direction of load change.

[0057] Then the dynamic equation of the power flow state of the power grid considering the load change state and the photovoltaic system access state is as follows: ;

[0058] is the access state matrix of the photovoltaic system, is the discrete state variable of the power flow state dynamic equation; the access state matrix of the photovoltaic system The element in the matrix is ​​1 or 0, and is connected to the state matrix The element 1 indicates that the corresponding photovoltaic system is connected to the grid, and the access state matrix The middle element is 0, indicating that the corresponding PV system is off-grid;

[0059] is the voltage amplitude of all grid nodes and phase angle ;

[0060] is the load change state. The elements in the load change state are -1 or 1, which are used to control the load change direction. is the load scaling factor, which is used to control the load change ratio;

[0061] is a function that represents the internal relationship of the state variables, is the derivative of the continuous state variable under any photovoltaic access state.

[0062] Achieve the expected load power The corresponding load scaling factor is , considering the discrete photovoltaic system access state, then To meet the expected load power stability constraints.

[0063] To meet the expected load power Under the control of the stability constraint, the planning space is determined within the range of the initial value and the minimum value of the low voltage ride-through limit; based on the expected load power Find the expected voltage value for each PV system in the grid from the PV curve of each PV system ; For the candidate objects, set the low voltage ride-through limit of any PV system combination in the candidate objects to the expected voltage value Get several solutions as planning space. Take a power grid with five photovoltaic systems as an example, where three photovoltaic systems PV1, PV2 and PV2 are selected as candidates, and set the low voltage ride-through limit of any combination of photovoltaic systems in the candidate to the expected voltage value Several solutions are obtained as planning space, including PV1, PV2, PV3, PV1 and PV2, PV1 and PV3, PV2 and PV3, and PV1, PV2 and PV3 changing the low voltage ride-through limit setting, for a total of 7 situations.

[0064] The impact of each photovoltaic system connected or disconnected in the grid on the load is different. The relationship formula between the photovoltaic access status and the load is determined according to the impact of each photovoltaic system access status on the grid load. According to the relationship formula between the photovoltaic access status and the load, a power greater than the expected load power is taken from the planning space. scheme as a candidate scheme.

[0065] In the specific implementation process, Figure 3 As shown, when the power flow state dynamic equation: When the power grid is stable, considering the discrete photovoltaic system access state, then When the power grid is stable, the generator is in the limit state, and the stability constraint Differentiate to get:

[0066] ;

[0067] based on and The relationship between them determines the impact of the photovoltaic system access status on the grid load include:

[0068] set up ,but:

[0069] ,

[0070] ;

[0071] The relationship between photovoltaic access status and load is determined according to the influence of each photovoltaic system access status on the grid load:

[0072] .

[0073] The grid load scaling factor corresponding to each PV system access state changes. In the planning space scheme, when multiple PV systems change their configurations at the same time, we get , then the load of the corresponding solution is:

[0074] ;

[0075] in, is the impact of photovoltaic access status on load, For the candidate solution, it is the change of the candidate solution relative to the total disconnection of the candidate object. is the load scaling factor corresponding to when all candidate objects are offline, is the load scaling factor of the solution in the corresponding planning space.

[0076] For the solutions in the planning space, , select it as a candidate solution.

[0077] The candidate solutions are optimized with the goal of minimizing the change in the low voltage ride-through limit of the entire PV system.

[0078] The present application proposes a method for configuring photovoltaic low voltage ride-through that is adaptive to loads. The present application sets the expected load power, the initial value and the minimum value of the low voltage ride-through limit of each photovoltaic system; checks whether the generator can meet the expected load power when the power grid maintains the expected load power under the current low voltage ride-through limit conditions so that the photovoltaic system is normally disconnected from the grid. If so, the photovoltaic system is normally disconnected from the grid; if not, then: all photovoltaic systems that are disconnected from the grid and expected to be disconnected from the grid are used as candidates for adjusting the photovoltaic low voltage ride-through configuration; under the stability constraint of meeting the expected load power, within the range of the initial value and the minimum value of the low voltage ride-through limit, determine the planning space; select a solution with a power greater than the expected load as a candidate solution from the planning space according to the relationship formula between the photovoltaic access state and the load, and take the candidate solution that minimizes the low voltage ride-through limit. The photovoltaic low voltage ride-through configuration of the present invention is adapted to the ever-changing load demand and reduces harmful photovoltaic system tripping.

[0079] Example 2

[0080] See also Figure 4 As shown, an embodiment of the present invention provides a load-adaptive photovoltaic low voltage ride-through configuration device, comprising: at least one processing unit, the processing unit is connected to a storage unit and a collection unit through a bus unit, the collection unit collects parameters required by a load-adaptive photovoltaic low voltage ride-through configuration method from each photovoltaic system and generator, the storage unit is a computer-readable storage medium, and can be used to store software programs, computer executable programs, and modules, such as the software programs, computer executable programs, and modules corresponding to a load-adaptive photovoltaic low voltage ride-through configuration method in an embodiment of the present invention. The processing unit implements the above-mentioned load-adaptive photovoltaic low voltage ride-through configuration method by running the software programs, computer executable programs, and modules stored in the storage unit, including:

[0081] Pre-set the expected load power that can meet user needs , the initial value and minimum value of the low voltage ride-through limit in the low voltage ride-through curve of each PV system;

[0082] Verify that the PV system maintains the expected load power under the current low voltage ride-through limit conditions , and when the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? If yes, the PV system is disconnected from the grid normally; if no, then:

[0083] The photovoltaic systems that are completely disconnected and expected to be disconnected are taken as candidates for adjusting the low voltage ride-through configuration, and the low voltage ride-through configuration of the remaining photovoltaic systems remains unchanged; the power flow state dynamic equation that introduces the photovoltaic access state is used to determine the load power that meets the expected load Stability constraints; when satisfying the expected load power Under the control of the stability constraint, the planning space is determined within the range of the initial value and the minimum value of the low voltage ride-through limit; the relationship formula between the photovoltaic access state and the load is determined according to the influence of each photovoltaic system access state on the grid load, and a value greater than the expected load power is taken from the planning space according to the relationship formula between the photovoltaic access state and the load. The scheme is taken as a candidate scheme, and the candidate scheme is optimized with the goal of minimizing the change in the low voltage ride-through limit of the entire PV system.

[0084] Of course, the computer program stored in the storage unit of the load-adaptive photovoltaic low voltage ride-through configuration device provided in an embodiment of the present invention is not limited to the method operation described above, and can also execute the relevant operations in the load-adaptive photovoltaic low voltage ride-through configuration method provided in any embodiment of the present invention.

[0085] Example 3

[0086] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed, the method for configuring a load-adaptive photovoltaic low voltage ride-through is implemented, including:

[0087] Pre-set the expected load power that can meet user needs , the initial value and minimum value of the low voltage ride-through limit in the low voltage ride-through curve of each PV system;

[0088] Verify that the PV system maintains the expected load power under the current low voltage ride-through limit conditions , and when the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? If yes, the PV system is disconnected from the grid normally; if no, then:

[0089] The photovoltaic systems that are completely disconnected and expected to be disconnected are taken as candidates for adjusting the low voltage ride-through configuration, and the low voltage ride-through configuration of the remaining photovoltaic systems remains unchanged; the power flow state dynamic equation that introduces the photovoltaic access state is used to determine the load power that meets the expected load Stability constraints; when satisfying the expected load power Under the control of the stability constraint, the planning space is determined within the range of the initial value and the minimum value of the low voltage ride-through limit; the relationship formula between the photovoltaic access state and the load is determined according to the influence of each photovoltaic system access state on the grid load, and a value greater than the expected load power is taken from the planning space according to the relationship formula between the photovoltaic access state and the load. The scheme is taken as a candidate scheme, and the candidate scheme is optimized with the goal of minimizing the change in the low voltage ride-through limit of the entire PV system.

[0090] A computer-readable storage medium provided in an embodiment of the present invention stores a computer program which is not limited to the method operations described above, but can also execute related operations in a load-adaptive photovoltaic low voltage ride-through configuration method provided in any embodiment of the present invention.

[0091] In the embodiments provided by the present invention, it should be understood that the disclosed structures and methods can be implemented in other ways. For example, the structural embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, structures or units, which can be electrical, mechanical or other forms.

[0092] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0093] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0094] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for configuring photovoltaic low voltage ride-through adapted to load, characterized in that: include: Pre-set the expected load power that can meet user needs , the initial value and minimum value of the low voltage ride-through limit in the low voltage ride-through curve of each PV system; Verify that the PV system maintains the expected load power under the current low voltage ride-through limit conditions , and when the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? If yes, the PV system is disconnected from the grid normally; if no, then: The photovoltaic systems that are completely disconnected and expected to be disconnected are taken as candidates for adjusting the low voltage ride-through configuration, and the low voltage ride-through configuration of the remaining photovoltaic systems remains unchanged; the power flow state dynamic equation that introduces the photovoltaic access state is used to determine the load power that meets the expected load Stability constraints; when satisfying the expected load power Under the control of the stability constraint, the planning space is determined within the range of the initial value and the minimum value of the low voltage ride-through limit; the relationship formula between the photovoltaic access state and the load is determined according to the influence of each photovoltaic system access state on the grid load, and a value greater than the expected load power is taken from the planning space according to the relationship formula between the photovoltaic access state and the load. The scheme is taken as a candidate scheme; the candidate scheme is optimized with the goal of minimizing the change in the low voltage ride-through limit of the entire photovoltaic system.

2. A method for configuring a photovoltaic low voltage ride-through adapted to a load according to claim 1, characterized in that: A mapping table of the minimum value of the low voltage ride-through limit with regional, time and climate changes is constructed. During operation, the minimum value of the low voltage ride-through limit is matched from the mapping table according to the region, time and regional climate conditions of the photovoltaic system. For any photovoltaic system, the minimum value of the low voltage ride-through limit under any regional, time and climate change conditions is less than the initial value of the low voltage ride-through limit.

3. A method for configuring a photovoltaic low voltage ride-through adapted to a load according to claim 1, characterized in that: Verify that the PV system maintains the expected load power under the current low voltage ride-through limit conditions , and when the photovoltaic system is normally disconnected from the grid, can the generator meet the expected load power? include: Get the current low voltage ride-through limit and PV curve for each PV system; Based on expected load power Find the expected voltage value for each PV system in the grid from the PV curve of each PV system ; Based on the expected voltage value The current low voltage ride-through limit is used to determine whether each PV system violates the low voltage ride-through limit, and a simulation is performed to calculate whether the generator power can meet the expected voltage value after the PV system that violates the low voltage ride-through limit is disconnected from the grid.

4. A method for configuring a photovoltaic low voltage ride-through adapted to a load according to claim 1, characterized in that: Considering the load change state and the photovoltaic system access state, the power flow state dynamic equation of the power grid is constructed in the form of: ; is the access state matrix of the photovoltaic system, Belongs to the discrete state variables in the dynamic equation of the power flow state; the access state matrix of the photovoltaic system The element in the matrix is ​​1 or 0, and is connected to the state matrix The element 1 indicates that the corresponding photovoltaic system is connected to the grid, and the access state matrix The middle element is 0, indicating that the corresponding PV system is off-grid; is the voltage amplitude of all grid nodes and phase angle ; is the load change state. The elements in the load change state are -1 or 1, which are used to control the load change direction. is the load scaling factor, which is used to control the load change ratio; is a function that represents the internal relationship of the state variables, is the derivative of the continuous state variable under any photovoltaic access state.

5. A method for configuring a photovoltaic low voltage ride-through adapted to load according to claim 4, characterized in that: Achieve the expected load power The corresponding load scaling factor is , considering the discrete photovoltaic system access state, then To meet the expected load power stability constraints.

6. A method for configuring a photovoltaic low voltage ride-through adapted to load according to claim 1, characterized in that: Based on expected load power Find the expected voltage value for each PV system in the grid from the PV curve of each PV system ; For the candidate objects, set the low voltage ride-through limit of any PV system combination in the candidate objects to the expected voltage value Get several plans to use as planning space.

7. A method for configuring a photovoltaic low voltage ride-through adapted to load according to claim 5, characterized in that: The relationship between photovoltaic access status and load is determined according to the influence of each photovoltaic system access status on the grid load: ， in, is the impact of photovoltaic access status on load, For the candidate solution, it is the change of the candidate solution relative to the total disconnection of the candidate object. is the load scaling factor corresponding to when all candidate objects are offline, is the load scaling factor of the solution in the corresponding planning space.

8. A method for configuring a photovoltaic low voltage ride-through adapted to load according to claim 7, characterized in that: When the power grid is stable, considering the discrete photovoltaic system access state, then When the power grid is stable, the process of solving the influence of each photovoltaic system access state on the grid load includes: when the generator is in the limit state, the stability constraint Differentiate to get: ； based on and The relationship between them determines the impact of the photovoltaic system access status on the grid load include: set up ,but: ， ； The relationship between photovoltaic access status and load is determined according to the influence of each photovoltaic system access status on the grid load: 。 9. A photovoltaic low voltage ride-through configuration device adapted to load, characterized in that: include: At least one processing unit, the processing unit is connected to a storage unit and a collection unit through a bus unit, the collection unit collects parameters required for a load-adaptive photovoltaic low voltage ride-through configuration method from each photovoltaic system and generator, the storage unit stores a computer program, and when the computer program is executed by the processing unit, a load-adaptive photovoltaic low voltage ride-through configuration method as described in any one of claims 1-8 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, a load-adaptive photovoltaic low voltage ride-through configuration method as described in any one of claims 1 to 8 is implemented.

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