A photovoltaic inverter transient model construction method, device and terminal equipment

Abstract

The embodiment of the present application relates to the technical field of power distribution network photovoltaic inverter, and discloses a photovoltaic inverter transient model construction method.The photovoltaic inverter transient model construction method comprises the following steps: setting fault information through a photovoltaic power generation network model, and sending the fault information to a photovoltaic inverter; collecting first test information of the photovoltaic inverter, wherein the first test information is electrical data within a preset time before and after the photovoltaic inverter receives the fault information; performing parameter identification based on the first test information to obtain first parameters, and constructing an initial model of the photovoltaic inverter according to the first parameters; inputting the fault information into the initial model of the photovoltaic inverter to obtain second test information, wherein the second test information is electrical data within a preset time before and after the initial model of the photovoltaic inverter receives the fault information; calculating a deviation amount of the first test information and the second test information, correcting parameters of the initial model of the photovoltaic inverter according to the deviation amount to obtain second parameters, and constructing a transient model of the photovoltaic inverter according to the second parameters.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic inverter technology for power distribution networks, specifically to a method, apparatus, and terminal equipment for constructing transient models of photovoltaic inverters. Background Technology

[0002] With economic and social development, new energy sources such as photovoltaic and wind power, due to their clean, efficient, and renewable characteristics, are gradually replacing fossil fuels and becoming important energy generation channels. As of 2021, my country's newly installed renewable energy capacity reached 134 million kilowatts, accounting for 76.1% of the country's total new power generation capacity. Photovoltaic power generation technology is now relatively mature and is being used more and more widely both domestically and internationally.

[0003] Transient stability of a power system refers to its ability to recover to a state close to its original operating condition after being subjected to a disturbance of a certain magnitude that appears momentarily and disappears immediately; or, although the disturbance does not disappear, the system may safely transition from its original operating condition to a new one. Transient calculation plays a crucial role in power system planning and operation analysis. It not only provides a check on the transient stability of the power source layout, network wiring, reactive power compensation, and protection configuration of the planned system, and provides a reliable basis for formulating power system operation procedures, but it can also be used to study various measures to improve transient stability and to provide a basis for setting parameters of relay protection and automatic devices.

[0004] With the continuous increase in renewable energy capacity, power system transient stability calculations are becoming increasingly important. Compared with traditional energy sources, renewable energy installations place higher demands on the comprehensive configuration and computational capabilities of the distribution network in terms of transient stability. When the proportion of renewable energy installations is small, the transient characteristics of renewable energy can be ignored in power system transient calculations. However, with the continuous increase in renewable energy installation capacity, the stability characteristics of the power system undergo profound changes, increasing the difficulty of control and posing a severe challenge to power system analysis and calculation. Ignoring the transient characteristics of renewable energy, or using typical renewable energy models (which cannot accurately represent all renewable energy transient characteristics), can no longer accurately reflect their operating characteristics, resulting in significant errors in calculation results that can easily affect grid operation decisions. Therefore, it is urgent to develop transient characteristic modeling that considers the large-scale integration of renewable energy.

[0005] A photovoltaic (PV) inverter is an inverter that converts the variable DC voltage generated by photovoltaic (PV) solar panels into AC power at the grid frequency. This AC power can be fed back into commercial transmission systems or supplied to off-grid power grids. PV inverters are an important component of the balance of systems (BOS) in PV array systems, possessing special functions tailored to the PV array, such as maximum power point tracking and islanding protection. They can also be used with general AC-powered equipment.

[0006] However, in existing power distribution network characteristic modeling, the default general model of photovoltaic inverters in the modeling software is often used when modeling photovoltaic inverters. This model is a static model with fixed parameters and cannot reflect the transient characteristics of photovoltaic inverters before and after power system disturbances. Summary of the Invention

[0007] In view of this, embodiments of the present invention provide a method, apparatus and terminal equipment for constructing a transient model of a photovoltaic inverter, thereby constructing a transient model of a photovoltaic inverter that can reflect the transient characteristics of a power system.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, embodiments of the present invention provide a method for constructing a transient model of a photovoltaic inverter, comprising: setting fault information through a photovoltaic power generation network model and sending the fault information to a photovoltaic inverter; collecting first test information of the photovoltaic inverter, wherein the first test information is electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information; identifying parameters based on the first test information to obtain first parameters, and constructing an initial model of the photovoltaic inverter based on the first parameters; inputting the fault information into the initial model of the photovoltaic inverter to obtain second test information, wherein the second test information is electrical data of the initial model of the photovoltaic inverter within a preset time before and after receiving the fault information; calculating the deviation between the first test information and the second test information, correcting the parameters of the initial model of the photovoltaic inverter based on the deviation to obtain second parameters, and constructing a transient model of the photovoltaic inverter based on the second parameters.

[0010] This invention simulates and tests a photovoltaic inverter using a photovoltaic power generation network model, testing data under various fault conditions. Parameters are identified based on the test data, and verified through two rounds of testing until preset error requirements are met. This yields an actual transient model of the inverter, which can be used for power system transient calculations. This model not only provides a check on the rationality of power supply layout, network wiring, reactive power compensation, and protection configuration in planning systems, and offers a reliable basis for formulating power system operation procedures, but it can also be used to study various measures to improve transient stability and provide a basis for setting parameters for relay protection and automatic devices.

[0011] Based on the first aspect, in some embodiments, before setting fault information through the photovoltaic power generation network model and sending the fault information to the photovoltaic inverter, the method further includes: constructing a photovoltaic power generation network model based on the photovoltaic distribution network topology; and configuring the photovoltaic power generation network model operating parameters.

[0012] Based on the first aspect, in some embodiments, the photovoltaic power generation network model is mounted on the host computer of the power real-time simulation system; wherein, the power real-time simulation system includes the host computer and the photovoltaic inverter, and the output port of the host computer is connected to the controller port of the photovoltaic inverter.

[0013] Based on the first aspect, in some embodiments, the photovoltaic distribution network topology includes a photovoltaic array, a boost circuit, a photovoltaic inverter, an LC filter circuit, a grid-connected switch, a step-up transformer, a grid voltage disturbance device, an equivalent impedance, and a power grid, connected in sequence.

[0014] Based on the first aspect, in some embodiments, configuring the operating parameters of the photovoltaic power generation network model includes: setting the parameters of the host computer input port and output port according to the topology voltage and current measurement loop of the photovoltaic power generation network model; after the host computer output port is connected to the photovoltaic inverter controller port, setting the analog signal transformation ratio sent by the photovoltaic power generation network model to the photovoltaic inverter according to the signal transformation ratio collected at the photovoltaic inverter controller port.

[0015] Based on the first aspect, in some embodiments, the first test information includes the three-phase voltage and three-phase current of the photovoltaic inverter on the AC side, and the inverter output active power, reactive power, positive sequence voltage and reactive current on the AC side calculated based on the three-phase voltage and three-phase current of the photovoltaic inverter on the AC side.

[0016] Based on the first aspect, in some embodiments, the fault information includes power range, fault type, voltage drop magnitude, and voltage drop duration.

[0017] Secondly, embodiments of the present invention provide a photovoltaic inverter transient model construction device, comprising: a fault testing module, used to set fault information through a photovoltaic power generation network model and send the fault information to the photovoltaic inverter; an information acquisition module, used to acquire first test information of the photovoltaic inverter, the first test information being electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information; a model construction module, used to perform parameter identification based on the first test information to obtain first parameters, and construct an initial model of the photovoltaic inverter based on the first parameters; input the fault information into the initial model of the photovoltaic inverter to obtain second test information, the second test information being electrical data of the initial model of the photovoltaic inverter within a preset time before and after receiving the fault information; calculate the deviation between the first test information and the second test information, correct the parameters of the initial model of the photovoltaic inverter based on the deviation to obtain second parameters, and construct a transient model of the photovoltaic inverter based on the second parameters.

[0018] Thirdly, embodiments of the present invention provide a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the steps of any of the photovoltaic inverter transient model construction methods described in the first aspect above.

[0019] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the steps of any of the photovoltaic inverter transient model construction methods described in the first aspect above. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the photovoltaic inverter transient model construction method provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of a photovoltaic power distribution network topology provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the power real-time simulation system structure provided in an embodiment of the present invention;

[0024] Figure 4 This is a graph showing test data of a photovoltaic inverter provided in an embodiment of the present invention;

[0025] Figure 5 A schematic diagram of a photovoltaic inverter transient model construction device provided in an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of a terminal device provided in an embodiment of the present invention. Detailed Implementation

[0027] The present invention will be described more clearly below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the function of the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0029] With the continuous increase in new energy capacity, power system transient stability calculations are becoming increasingly important. Power system transient stability refers to the ability of a normally operating power system to recover to a state close to its original operating condition after being subjected to a disturbance of a certain magnitude that appears momentarily and disappears immediately; or, although the disturbance does not disappear, the system's ability to safely transition from its original operating condition to a new one. Transient stability calculations occupy an important position in power system planning and operation analysis. They not only provide a check on the transient stability of the planned power source layout, network wiring, reactive power compensation, and protection configuration, and offer a reliable basis for formulating power system operation procedures, but also can be used to study various measures to improve transient stability and provide a basis for setting parameters for relay protection and automatic devices.

[0030] When the proportion of renewable energy installed capacity is small, the transient characteristics of renewable energy can be ignored in power system transient calculations. However, as the installed capacity of renewable energy continues to increase, the transient stability characteristics of the power system also undergo profound changes, increasing the difficulty of control and posing a severe challenge to power system analysis and calculation. Power system transient models that do not consider the transient characteristics of renewable energy, or that use typical renewable energy models (which cannot accurately represent all the transient characteristics of renewable energy), can no longer accurately reflect the operating characteristics of the power system. Their calculation results contain large errors and can easily affect the decision-making of grid operation modes.

[0031] Based on the above application scenarios, this invention provides a method for constructing a transient model of a photovoltaic inverter, such as... Figure 1 As shown, the method for constructing the transient model of the photovoltaic inverter includes steps 101 to 103.

[0032] Step 101: Set fault information through the photovoltaic power generation network model and send the fault information to the photovoltaic inverter.

[0033] Before setting fault information through the photovoltaic power generation network model and sending the fault information to the photovoltaic inverter, the photovoltaic power generation network model is constructed based on the photovoltaic distribution network topology.

[0034] In some embodiments, such as Figure 2 As shown, the photovoltaic power distribution network topology includes a photovoltaic array, a boost circuit, a photovoltaic inverter, an LC filter circuit, a grid-connected switch, a step-up transformer, a grid voltage disturbance device, an equivalent impedance, and the power grid, connected in sequence.

[0035] In some embodiments, such as Figure 3As shown, the real-time power simulation system includes a host computer and a photovoltaic inverter, with the host computer's output port connected to the photovoltaic inverter's controller port. Based on the aforementioned photovoltaic power distribution network topology, a photovoltaic power generation network model is built in the host computer software (such as Simulink) of the real-time power simulation system (e.g., RT-LAB).

[0036] Before testing, the operating parameters of the photovoltaic power generation network model need to be configured. Based on the signals that the inverter controller needs to collect, the topology voltage and current measurement loops of the photovoltaic power generation network model are set. According to the topology voltage and current measurement loops of the photovoltaic power generation network model, the parameters of the host computer's analog output port and digital input port are set.

[0037] After the host computer output port is connected to the photovoltaic inverter controller port, the analog signal ratio sent by the photovoltaic power generation network model to the photovoltaic inverter is set according to the signal ratio collected at the photovoltaic inverter controller port.

[0038] In some embodiments, various fault information is set in the host computer software, as shown in Table 1. The fault information includes power range, fault type, voltage drop amplitude, and voltage drop duration. The fault information is then sent to the photovoltaic inverter.

[0039] Step 102: Collect the first test information of the photovoltaic inverter, wherein the first test information is the electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information.

[0040] After the fault information is sent to the photovoltaic inverter, the first test information of the photovoltaic inverter is collected by the power recording and analysis instrument. The first test information is the electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information.

[0041] Step 103: Based on the first test information, perform parameter identification to obtain the first parameter, and construct the initial model of the photovoltaic inverter based on the first parameter.

[0042] In some embodiments, after obtaining the first test information through the power recording analyzer, the parameters are identified through the preset photovoltaic grid-connected inverter model in the power system analysis and calculation software BPA. The least squares method can be used for identification. After identification, the first parameter is obtained. The first test information is the electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information.

[0043] The first test information includes the three-phase voltage and three-phase current of the photovoltaic inverter on the AC side, and the inverter output active power, reactive power, positive sequence voltage and reactive current calculated based on the three-phase voltage and three-phase current of the photovoltaic inverter on the AC side.

[0044] The first parameter is entered into the power system analysis and calculation software BPA to obtain the initial model of the photovoltaic inverter.

[0045] Step 104: Input the fault information into the photovoltaic inverter initial model to obtain the second test information. The second test information is the electrical data of the photovoltaic inverter initial model before and after receiving the fault information within a preset time period.

[0046] The specific electrical data type is the same as the first test information type.

[0047] Step 105: Calculate the deviation between the first test information and the second test information, correct the parameters of the initial model of the photovoltaic inverter according to the deviation, obtain the second parameters, and construct the transient model of the photovoltaic inverter according to the second parameters.

[0048] The first and second test information are divided into three time periods: before the disturbance (A), during the disturbance (B), and after the disturbance (C). Based on the response characteristics of current, active power, and reactive power, the disturbance period is divided into a transient interval (B1) and a steady-state interval (B2), and the post-disturbance period is divided into a transient interval (C1) and a steady-state interval (C2).

[0049] Deviation calculations are performed on the pre-disturbance, transient interval during the disturbance, steady-state interval during the disturbance, post-disturbance transient interval, and post-disturbance steady-state interval. This includes the average deviation of the steady-state interval, the average deviation of the transient interval, and the maximum deviation of the steady-state interval. The weighted average total deviation of all intervals is calculated with weights of 0.1, 0.6, and 0.3 for the three time periods before, during, and after the disturbance, respectively.

[0050] If the deviations of voltage deviation, current, reactive current, active power, and reactive power under all fault information categories do not meet the preset error requirements, the first parameter is adjusted until the deviation meets the error requirements. At this point, the second parameter is obtained, and a transient model of the photovoltaic inverter is constructed based on the second parameter.

[0051] Example 1

[0052] A transient model of a photovoltaic inverter of a certain model was constructed. Multiple fault types were set in the host computer software. The fault information settings are shown in Table 1, with a total of 24 fault conditions.

[0053] Table 1 Fault Information

[0054]

[0055] All parameters of the photovoltaic inverter are shown in Tables 2, 3 and 4.

[0056] Table 2. Parameters of the Low Voltage Ride-Through State Judgment Model (EV Card)

[0057]

[0058] Table 3. Active power control model parameters during and after low voltage ride-through (LP card)

[0059]

[0060]

[0061] Table 4. Reactive power control model parameters during and after low voltage ride-through (LQ card)

[0062]

[0063]

[0064] The power logging analyzer records the inverter's operating data under the 24 fault conditions listed in Table 1, as follows: Figure 4 As shown.

[0065] The parameters were identified based on the inverter transient model in BPA, and the identification results are shown in Tables 5, 6 and 7 below.

[0066] Table 5. Identification Results of Low Voltage Ride-Through State Judgment Model Parameters (EV Card)

[0067] Serial Number Parameter name Parameter identification results 1 VOL_TYP1 1 2 VOL_LOW 0.89 3 VOL_LOW_RET 0.91 4 VOL_LOW_DELAY 0.1

[0068] Table 6. Identification results of active power control model parameters (LP card) during and after low voltage ride-through.

[0069] Serial Number Parameter name Parameter identification results 1 IRT_CON 1 2 IP_FLG 2 3 IP_SET 62 4 TDELAY 0 5 IP_FLG2 2 6 IP_RET_SET -1 7 IP_RET_TIME 0 8 IP_RATE_FLG 1 9 IP_RATE 0.3 10 IP_RATE2 0.2 11 P_RATE_CHANGE 0.12 12 TP / 13 IPI_COM 0 14 PI_K1 / 15 PI_K2 / 16 IP_RATE_FLG2 0

[0070] Table 7. Identification Results of Reactive Power Control Model Parameters (LQ Card) During and After Low Voltage Ride-Through.

[0071] Serial Number Parameter name Parameter identification results 1 ICON_TYP 0 2 VOLTYP 0 3 VOL_REF 0.9 4 Q_RATE 1.78 5 ICONTYP2 2 6 KQ2 1.78 7 IQMAX 60 8 IQ_FLG 0 9 IQ_START / 10 IQ_TP / 11 IQLIM /

[0072] The definition of deviation and the preset error requirements are shown in Tables 8 and 9 below.

[0073] Table 8. Definition of Deviation

[0074] symbol definition symbol definition A Steady-state range before disturbance F3_I Maximum deviation of current in steady-state range B1 Transient interval during disturbance F1_P Average deviation of active power in steady-state range B2 steady-state interval during disturbance F2_P Average deviation of active power in transient interval C1 Transient interval after disturbance F3_P Maximum deviation of active power in steady-state range C2 Steady-state range after disturbance F1_Q Average deviation of reactive power in steady-state range F1_U Average voltage deviation in steady-state range F2_Q Average deviation of reactive power in transient interval F2_U Average deviation of voltage in transient interval F3_Q Maximum deviation of reactive power in steady state range F3_U Maximum voltage deviation in steady-state range FG_U Voltage weighted average absolute deviation F1_IQ Average deviation of reactive current in steady state range FG_IQ Reactive current weighted average absolute deviation F2_IQ Average deviation of reactive current in transient interval FG_I Current weighted average absolute deviation F3_IQ Maximum deviation of reactive current in steady state range FG_P Weighted average absolute deviation of active power F1_I steady-state current average deviation FG_Q Reactive power weighted average absolute deviation F2_I Average deviation of current in transient interval

[0075] Table 9 Maximum Permissible Deviation Values

[0076]

[0077] The identified parameters were entered into the power system analysis and calculation software BPA. Multiple fault types were set and relevant data were recorded. Error calculations were then performed using this data and the inverter operating data recorded by the power recording and analysis instrument. The error calculation results for 24 fault conditions are shown in Tables 10 to 33 below.

[0078] Table 10 Deviation Calculation Results for Operating Condition 1

[0079]

[0080] Table 11 Deviation Calculation Results for Operating Condition 2

[0081]

[0082]

[0083] Table 12 Calculation results of deviations under operating condition 3

[0084]

[0085] Table 13 Deviation Calculation Results for Operating Condition 4

[0086]

[0087] Table 14 Deviation Calculation Results for Operating Condition 5

[0088]

[0089] Table 15 Deviation Calculation Results for Operating Condition 6

[0090]

[0091] Table 16 Deviation Calculation Results for Operating Condition 7

[0092]

[0093] Table 17 Deviation Calculation Results for Operating Condition 8

[0094]

[0095]

[0096] Table 18 Deviation Calculation Results for Operating Condition 9

[0097]

[0098] Table 19 Deviation Calculation Results for Operating Condition 10

[0099]

[0100] Table 20 Deviation Calculation Results for Operating Condition 11

[0101]

[0102] Table 21 Deviation Calculation Results for Operating Condition 12

[0103]

[0104] Table 22 Deviation Calculation Results for Operating Condition 13

[0105]

[0106] Table 23 Deviation Calculation Results for Operating Condition 14

[0107]

[0108]

[0109] Table 24 Deviation Calculation Results for Operating Condition 15

[0110]

[0111] Table 25 Deviation Calculation Results for Operating Condition 16

[0112]

[0113] Table 26 Deviation Calculation Results for Operating Condition 17

[0114]

[0115] Table 27 Deviation Calculation Results for Operating Condition 18

[0116]

[0117] Table 28 Deviation Calculation Results for Operating Condition 19

[0118]

[0119] Table 29 Deviation Calculation Results for Operating Condition 20

[0120]

[0121] Table 30 Deviation Calculation Results for Operating Condition 21

[0122]

[0123] Table 31 Deviation Calculation Results for Operating Condition 22

[0124]

[0125] Table 32 Deviation Calculation Results for Operating Condition 23

[0126]

[0127] Table 33 Deviation Calculation Results for Operating Condition 24

[0128]

[0129] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0130] Corresponding to the photovoltaic inverter transient model construction method described in the above embodiments, Figure 5 The diagram shows a structural block diagram of the photovoltaic inverter transient model construction device provided in the embodiments of this application. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0131] See Figure 5 This invention provides a photovoltaic inverter transient model construction device 50, including: a fault testing module 510, an information acquisition module 520, and a model construction module 530.

[0132] The fault test module 510 is used to set fault information through the photovoltaic power generation network model and send the fault information to the photovoltaic inverter.

[0133] The information acquisition module 520 is used to acquire the first test information of the photovoltaic inverter, which is the electrical data of the photovoltaic inverter within a preset time before and after receiving fault information.

[0134] The model building module 530 is used to identify parameters based on the first test information, obtain the first parameters, and build an initial model of the photovoltaic inverter based on the first parameters; input the fault information into the initial model of the photovoltaic inverter to obtain the second test information, which is the electrical data of the initial model of the photovoltaic inverter within a preset time before and after receiving the fault information; calculate the deviation between the first test information and the second test information, correct the parameters of the initial model of the photovoltaic inverter based on the deviation, obtain the second parameters, and build a transient model of the photovoltaic inverter based on the second parameters.

[0135] Figure 6 This is a schematic diagram of a terminal device provided in an embodiment of the present invention. Figure 6 As shown, the terminal device 6 in this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60, such as a photovoltaic inverter transient model construction program. When the processor 60 executes the computer program 62, it implements the steps in the above-described photovoltaic inverter transient model construction method embodiment, for example... Figure 1Steps 101 to 103 are shown. Alternatively, when the processor 60 executes the computer program 62, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 5 The functions of modules 510 to 530 are shown.

[0136] For example, the computer program 62 can be divided into one or more modules / units, which are stored in the memory 61 and executed by the processor 60 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program 62 in the terminal device 6. For example, the computer program 62 can be divided into a fault testing module, an information acquisition module, and a model building module.

[0137] The terminal device 6 can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will understand that... Figure 6 This is merely an example of terminal device 6 and does not constitute a limitation on terminal device 6. It may include more or fewer components than shown, or combine certain components, or different components. For example, the terminal device may also include input / output devices, network access devices, buses, etc.

[0138] The processor 60 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0139] The memory 61 can be an internal storage unit of the terminal device 6, such as a hard disk or memory of the terminal device 6. The memory 61 can also be an external storage device of the terminal device 6, such as a plug-in hard disk, SmartMediaCard (SMC), SecureDigital (SD) card, or FlashCard equipped on the terminal device 6. Furthermore, the memory 61 can include both internal and external storage units of the terminal device 6. The memory 61 is used to store the computer program and other programs and data required by the terminal device. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0140] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the functions described above can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0141] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0142] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0143] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / terminal devices and methods can be implemented in other ways. For example, the apparatus / terminal device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0144] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0145] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0146] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0147] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for constructing a transient model of a photovoltaic inverter, characterized in that, include: Fault information is set through a photovoltaic power generation network model and then sent to the photovoltaic inverter. First test information of the photovoltaic inverter is collected, which is electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information; based on the first test information, parameter identification is performed to obtain the first parameter, and an initial model of the photovoltaic inverter is constructed according to the first parameter; The fault information includes power range, fault type, voltage drop magnitude, and voltage drop duration; The fault information is input into the photovoltaic inverter initial model to obtain the second test information, which is the electrical data of the photovoltaic inverter initial model before and after receiving the fault information within a preset time period. Calculate the deviation between the first test information and the second test information, correct the parameters of the initial model of the photovoltaic inverter based on the deviation, obtain the second parameters, and construct the transient model of the photovoltaic inverter based on the second parameters; The parameters of the initial model of the photovoltaic inverter are corrected according to the deviation amount, including: if the deviation amount does not meet the preset error requirement, the first parameter is corrected until the deviation amount meets the preset error requirement; The first test information and the second test information include three time periods: before the disturbance, during the disturbance, and after the disturbance; the period during the disturbance includes a transient interval and a steady-state interval, and the period after the disturbance includes a transient interval and a steady-state interval; The calculation of the deviation between the first test information and the second test information, the correction of the parameters of the initial model of the photovoltaic inverter based on the deviation to obtain the second parameter, and the construction of the transient model of the photovoltaic inverter based on the second parameter, includes: calculating the deviation for the transient interval before the disturbance, the steady-state interval during the disturbance, the transient interval after the disturbance, and the steady-state interval after the disturbance, including the average deviation of the steady-state interval, the average deviation of the transient interval, and the maximum deviation of the steady-state interval, and calculating the weighted average total deviation of all intervals according to the weights of the three time periods before the disturbance, during the disturbance, and after the disturbance.

2. The method for constructing a transient model of a photovoltaic inverter as described in claim 1, characterized in that, Before setting fault information through the photovoltaic power generation network model and sending the fault information to the photovoltaic inverter, the process also includes: The photovoltaic power generation network model is constructed based on the photovoltaic distribution network topology. Configure the operating parameters of the photovoltaic power generation network model.

3. The method for constructing a transient model of a photovoltaic inverter as described in claim 2, characterized in that, The photovoltaic power generation network model is mounted on the host computer of the real-time power simulation system. The real-time power simulation system includes a host computer and a photovoltaic inverter, with the output port of the host computer connected to the controller port of the photovoltaic inverter.

4. The method for constructing a transient model of a photovoltaic inverter as described in claim 2, characterized in that, The photovoltaic power distribution network topology includes a photovoltaic array, a boost circuit, a photovoltaic inverter, an LC filter circuit, a grid-connected switch, a step-up transformer, a grid voltage disturbance device, an equivalent impedance, and the power grid, connected in sequence.

5. The method for constructing a transient model of a photovoltaic inverter as described in claim 2, characterized in that, The configuration of the photovoltaic power generation network model operating parameters includes: Based on the topology voltage and current measurement loop of the photovoltaic power generation network model, set the parameters of the host computer input port and output port; After the host computer output port is connected to the photovoltaic inverter controller port, the analog signal ratio sent by the photovoltaic power generation network model to the photovoltaic inverter is set according to the signal ratio collected at the photovoltaic inverter controller port.

6. The method for constructing a transient model of a photovoltaic inverter as described in claim 1, characterized in that, The first test information includes the three-phase voltage and three-phase current of the photovoltaic inverter on the AC side, and the inverter output active power, reactive power, positive sequence voltage and reactive current calculated based on the three-phase voltage and three-phase current of the photovoltaic inverter on the AC side.

7. A device for constructing a transient model of a photovoltaic inverter, characterized in that, include: The fault testing module is used to set fault information through the photovoltaic power generation network model and send the fault information to the photovoltaic inverter. The information acquisition module is used to acquire the first test information of the photovoltaic inverter, which is the electrical data of the photovoltaic inverter within a preset time before and after receiving the fault information; the fault information includes power range, fault type, voltage drop amplitude and voltage drop duration. The model building module is used to identify parameters based on the first test information, obtain the first parameters, and build an initial model of the photovoltaic inverter based on the first parameters. The fault information is input into the photovoltaic inverter initial model to obtain the second test information, which is the electrical data of the photovoltaic inverter initial model before and after receiving the fault information within a preset time period. The deviation between the first test information and the second test information is calculated, and the parameters of the initial model of the photovoltaic inverter are corrected according to the deviation to obtain the second parameters. A transient model of the photovoltaic inverter is constructed based on the second parameters. The first test information and the second test information include three time periods: before the disturbance, during the disturbance, and after the disturbance. The disturbance period includes a transient interval and a steady-state interval, and the disturbance period includes a transient interval and a steady-state interval. The model building module is specifically used to: if the deviation does not meet the preset error requirement, then correct the first parameter until the deviation meets the preset error requirement; The model building module is also specifically used to: calculate the deviations for the pre-disturbance, transient interval during the disturbance, steady-state interval during the disturbance, post-disturbance transient interval, and post-disturbance steady-state interval, including the average deviation of the steady-state interval, the average deviation of the transient interval, and the maximum deviation of the steady-state interval, and calculate the weighted average total deviation of all intervals according to the weights of the three time periods before, during, and after the disturbance.

8. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the photovoltaic inverter transient model construction method as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the photovoltaic inverter transient model construction method as described in any one of claims 1 to 6.

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