New energy station grid connection configuration method, device, equipment, storage medium and product

Abstract

The application discloses a new energy station grid-connected configuration method, device, equipment, storage medium and product, relates to the technical field of power systems, and comprises the following steps: for each new energy station connected to a weak grid, determining the reactive power loss of each node based on the node voltage of each node in the station; the node is a transformer node, a converter node or a line node; based on all the reactive power losses, determining the first configuration capacity of the reactive power compensation device; predicting whether the short-circuit ratio of the grid-connected point is less than a preset short-circuit ratio after the reactive power compensation device operates based on the first configuration capacity; in the case that the short-circuit ratio is less than the preset short-circuit ratio, increasing the second configuration capacity of the network-forming unit until the predicted short-circuit ratio of the grid-connected point is greater than or equal to the preset short-circuit ratio after the network-forming unit operates based on the second configuration capacity; and determining the grid-connected configuration result of the new energy station based on the first configuration capacity and the second configuration capacity. The application can take into account the economy and system stability during the grid-connected construction of the new energy station.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, and particularly relates to a new energy station grid connection configuration method, device, equipment, storage medium and product. BACKGROUND

[0002] In the grid connection construction of a new energy station, short-circuit ratio is one of important indexes for measuring the support ability of a power grid to the station. In related technologies, some new energy stations are connected to areas with weak power grids, and the new energy stations dominated by grid-forming units have weak active support ability to the power grid. With the continuous expansion of the scale of the new energy station, some units have lower limit requirements for the short-circuit ratio of the access point. When the short-circuit ratio does not meet the access requirements, grid-forming units can be connected to improve the short-circuit ratio of the grid connection point. Generally, the access capacity configuration of the grid-forming unit is determined by taking the actual construction requirement of the short-circuit ratio of the grid connection point as a constraint condition.

[0003] However, the cost of the grid-forming unit equipment is high, and when the configuration capacity of the grid-forming unit is too large, the construction cost of the power system will inevitably be increased. Although the reactive power compensation device cannot completely replace the grid-forming unit to improve the short-circuit ratio of the grid connection point, it can provide reactive power compensation to maintain voltage stability, so as to reduce the access capacity of the grid-forming unit. Moreover, the economic efficiency of the reactive power compensation device is higher than that of the grid-forming unit. However, for a weak power grid, the reactive power loss obtained based on the approximate calculation method is quite different from the actual reactive power loss, which will affect the configuration accuracy. Therefore, how to balance the stability and economic efficiency of the power system during the construction of the new energy station has become a problem to be solved at present. SUMMARY

[0004] The main purpose of the present application is to provide a new energy station grid connection configuration method, device, equipment, storage medium and product, which aims to solve the technical problem that the grid connection construction of the new energy station in related technologies is difficult to balance the stability and economic efficiency of the system.

[0005] To achieve the above-mentioned purpose, the present application provides a new energy station grid connection configuration method, which can be used in a power system. The power system includes at least one new energy station, a reactive power compensation device, a grid-forming unit and a power grid. The new energy station, the reactive power compensation device and the grid-forming unit are connected to a grid connection point and connected to the power grid through an external impedance branch. The new energy station grid connection configuration method includes the following steps.

[0006] For each new energy station connected to a weak grid, the reactive power loss of each node in the new energy station is determined based on the node voltage of each node. The node is a transformer node, a converter node or a line node.

[0007] Based on all the reactive power losses, the first configuration capacity of the reactive power compensation device is determined.

[0008] The short-circuit ratio of the grid-connected point of the power system is determined after the reactive power compensation device operates based on the first configuration capacity.

[0009] In a case where the short-circuit ratio of the grid-connected point is less than the preset short-circuit ratio, the second configuration capacity of the grid-forming unit is increased until the short-circuit ratio of the grid-connected point obtained by prediction is greater than or equal to the preset short-circuit ratio after the grid-forming unit operates based on the second configuration capacity.

[0010] Based on the first configuration capacity and the second configuration capacity, a grid-connected configuration result of the new energy station is determined.

[0011] In an embodiment, before the step of determining the reactive power loss of each node based on the node voltage of each node in the new energy station, the method further comprises:

[0012] obtaining a rated node voltage corresponding to each node;

[0013] For each node, the rated node voltage corresponding to the node is corrected based on the circuit characteristic parameter of the external impedance branch to obtain the node voltage.

[0014] In an embodiment, the step of correcting the rated node voltage corresponding to the node based on the circuit characteristic parameter of the external impedance branch to obtain the node voltage comprises:

[0015] correcting the rated node voltage based on the calculation formula one to obtain the node voltage;

[0016] The calculation formula one is: ; wherein, the node voltage is, the rated node voltage is, the rated current of the external impedance branch is, the equivalent resistance of the external impedance branch is, the equivalent reactance of the external impedance branch is.

[0017] In an embodiment, the step of determining the reactive power loss of each node based on the node voltage of each node in the new energy station comprises:

[0018] determining the reactive power loss of each node based on the calculation formula two and the node voltage corresponding to each node;

[0019] The calculation formula two is: ;

[0020] wherein, the reactive power loss of the transformer node is, the reactive power loss of the line node is, the reactive power loss of the converter node is, the rated apparent power of the transformer node is, a rated apparent power of a line node, a transformer reactance, a line reactance, a line-to-ground capacitance, an equivalent impedance of a converter filter capacitance, a node voltage of a transformer node, a node voltage of a line node, a node voltage of a converter node.

[0021] In an embodiment, the step of determining the first configuration capacity of the reactive power compensation device based on all reactive power losses further comprises:

[0022] predicting whether the power factor of the grid-connected point is less than a preset power factor after the reactive power compensation device operates based on the first configuration capacity;

[0023] in the case that the power factor is less than the preset power factor, updating the first configuration capacity based on a preset reactive power compensation increment, and returning to perform the step of predicting whether the power factor of the grid-connected point is less than the preset power factor after the reactive power compensation device operates based on the first configuration capacity until the power factor is greater than or equal to the preset power factor.

[0024] In an embodiment, the third calculation formula of the grid-connected point short-circuit ratio is:

[0025] wherein, is the grid-connected point short-circuit ratio, n is the total number of new energy stations in the power system, is the short-circuit capacity provided by the power grid to the i th new energy station, is the active power injected by the i th new energy station, is the active power injected by the j th new energy station, is the mutual impedance between the i th new energy station and the j th new energy station under the current configuration, is the self-impedance of the i th new energy station under the current configuration.

[0026] In addition, to achieve the above-mentioned purpose, the application also provides a new energy station grid-connected configuration device for a power system, the power system comprising at least one new energy station, a reactive power compensation device, a grid-forming unit and a power grid, the new energy station, the reactive power compensation device and the grid-forming unit being connected to a grid-connected point and connected to the power grid through an external impedance branch; the new energy station grid-connected configuration device comprises:

[0027] a reactive power loss determination module configured to determine the reactive power loss of each node in the new energy station based on the node voltage of each node in the new energy station for each new energy station connected to a weak grid; the node is a transformer node, a converter node or a line node;

[0028] ​The first configuration capacity determination module is configured to determine the first configuration capacity of the reactive power compensation device based on all the reactive power losses.

[0029] The grid point short-circuit ratio prediction module is configured to predict whether the grid point short-circuit ratio of the power system after the reactive power compensation device operates based on the first configuration capacity is less than a preset short-circuit ratio.

[0030] The second configuration capacity determination module is configured to, in the case that the grid point short-circuit ratio is less than the preset short-circuit ratio, increase the second configuration capacity of the grid-forming unit until the predicted grid point short-circuit ratio is greater than or equal to the preset short-circuit ratio after the grid-forming unit operates based on the second configuration capacity.

[0031] The grid configuration result determination module is configured to determine the grid configuration result of the new energy station based on the first configuration capacity and the second configuration capacity.

[0032] In addition, to achieve the above-mentioned purpose, the present application also provides a new energy station grid configuration device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the computer program is configured to implement the steps of the new energy station grid configuration method as described above.

[0033] In addition, to achieve the above-mentioned purpose, the present application also provides a storage medium, which is a computer readable storage medium, and the storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the new energy station grid configuration method as described above.

[0034] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the steps of the new energy station grid configuration method as described above.

[0035] The one or more technical solutions provided by the present application have at least the following technical effects:

[0036] In the new energy station grid configuration method provided by the present application, the reactive power losses corresponding to each node can be determined based on the node voltage of each node in the new energy station. Thus, the first configuration capacity of the reactive power compensation device can be determined according to the reactive power losses. Then, it is predicted whether the grid point short-circuit ratio of the power system under this capacity configuration is less than the preset short-circuit ratio. If it is less than the preset short-circuit ratio, the second configuration capacity of the grid-forming unit is increased until the predicted grid point short-circuit ratio is greater than or equal to the preset short-circuit ratio. Based on the finally determined first configuration capacity of the reactive power compensation device and the second configuration capacity of the grid-forming unit, the grid configuration result of the new energy station can be determined.

[0037] The application can determine corresponding reactive power loss according to the voltage of each node in the new energy station grid connection construction, and adaptively configure to access the reactive power compensation device according to the reactive power loss, compensate the reactive power through the reactive power compensation device, improve the grid connection point voltage, and reduce the capacity demand of the system on the grid forming unit, thereby effectively reducing the construction cost of the new energy station grid connection; through the collaborative optimization configuration of the reactive power compensation device and the grid forming unit, the stability and economy of the power system are realized. BRIEF DESCRIPTION OF DRAWINGS

[0038] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the embodiment or related art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0040] Figure 1 The flowchart provided by the new energy station grid connection configuration method embodiment one of the present application;

[0041] Figure 2 The equivalent schematic diagram of an example power system;

[0042] Figure 3 The brief flowchart of the new energy station grid connection configuration method provided by the embodiment one of the present application;

[0043] Figure 4 The module structure schematic diagram of the new energy station grid connection configuration device of the embodiment of the present application;

[0044] Figure 5 The device structure schematic diagram of the hardware running environment involved in the new energy station grid connection configuration method in the embodiment of the present application.

[0045] The implementation of the purpose of the present application, the functional characteristics and the advantages will be further explained with reference to the drawings. DETAILED DESCRIPTION

[0046] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application, and are not used to limit the present application.

[0047] In order to better understand the technical solutions of the present application, the following will be described in detail in combination with the drawings in the specification and the specific implementation.

[0048] The main solution of the embodiment of the application is: for each new energy station accessing a weak network, the reactive power loss of each node in the new energy station is determined based on the node voltage of each node; the node is a transformer node, a converter node or a line node; based on all the reactive power losses, the first configuration capacity of the reactive power compensation device is determined; it is predicted whether the short-circuit ratio of the grid connection point of the power system is less than the preset short-circuit ratio after the reactive power compensation device operates based on the first configuration capacity; in the case that the short-circuit ratio of the grid connection point is less than the preset short-circuit ratio, the second configuration capacity of the grid-forming unit is increased until the predicted short-circuit ratio of the grid connection point is greater than or equal to the preset short-circuit ratio after the grid-forming unit operates based on the second configuration capacity; based on the first configuration capacity and the second configuration capacity, the grid connection configuration result of the new energy station is determined.

[0049] The new energy station dominated by the grid-following unit has relatively weak active support capability for the power grid, so some new energy station access areas present the characteristics of weak power grid, and the short-circuit ratio is one of the indicators for measuring the support capability of the power grid for the station. For example, the industry standard "GB / T 40581-2021 Power System Safety and Stability Calculation Specification" mentions the calculation method of the multi-station short-circuit ratio of the grid connection point of the new energy station, and proposes the requirements for the access of new energy multi-station to the alternating current system: the multi-station short-circuit ratio of the low-voltage side of the step-up transformer of the new energy power generation unit should not be less than 1.5, and the multi-station short-circuit ratio of the grid connection point of the new energy should not be less than 2.0, and preferably greater than 3.0. For the system with a short-circuit ratio less than 3.0, electromagnetic transient and electromechanical transient time domain simulation calculations should be performed to check the safety and stability level of the new energy grid connection system. Therefore, with the continuous expansion of the scale of the new energy station, it is an urgent problem to be solved to further improve the short-circuit ratio of the grid connection point.

[0050] In the related art, the grid connection point short-circuit ratio can be improved by accessing the grid-forming unit, and the access of the grid-forming unit can effectively improve the stability of the new energy station accessing the weak network; generally, the access capacity configuration of the grid-forming unit is determined by taking the actual construction requirement of the grid connection point short-circuit ratio as a constraint condition. However, due to the high cost of the grid-forming unit equipment, when the configuration capacity of the grid-forming unit is too large, the construction cost of the new energy station grid connection will inevitably increase. Therefore, how to balance the stability and economy of the power system during the construction of the new energy station has become a problem to be solved at present.

[0051] The application provides a solution, in the grid connection construction of the new energy station, the corresponding reactive power loss can be determined according to the voltage of each node, and the reactive power compensation device can be adaptively configured accordingly to access the reactive power compensation device, the reactive power compensation device is used for reactive power compensation, the voltage of the grid connection point is improved, and the capacity demand of the system for the grid-forming unit is reduced, thereby the construction cost of the new energy station grid connection can be effectively reduced; through the collaborative optimization configuration of the reactive power compensation device and the grid-forming unit, the stability and economy of the power system are balanced.

[0052] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication, and program execution capabilities, such as a tablet computer, personal computer, or an electronic device capable of performing the aforementioned functions. This embodiment and the following embodiments will be described below using the grid-connected configuration equipment of a new energy station as an example.

[0053] Based on this, the embodiment of the present application provides a new energy station grid connection configuration method, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the method for configuring the grid connection of a new energy station in this application.

[0054] In this embodiment, the new energy station grid connection configuration method includes steps S100 to S500:

[0055] Step S100 : for each new energy station connected to a weak network, the reactive loss of each node is determined based on the node voltage of each node in the new energy station.

[0056] The node is a transformer node, a converter node or a line node.

[0057] Step S200: determining a first configuration capacity of a reactive power compensation device based on all reactive power losses.

[0058] It should be noted that the new energy station grid-connected configuration method provided in this embodiment can be used for a power system in which a grid-connected new energy station is connected to the grid. Figure 2 is an equivalent schematic diagram of an example power system, such as Figure 2 As shown, the power system includes at least one new energy station (the first station or the second station connected to the weak network, etc.), a reactive power compensation device, a grid-forming unit and a power grid. The new energy station, the reactive power compensation device and the grid-forming unit are all gathered at the grid connection point M and connected to the power grid through an external impedance branch. The specific number of new energy stations connected to the power grid in the above power system is generally determined according to actual construction needs. Figure 2 As shown in the figure, each new energy site includes multiple branches, each of which corresponds to a box transformer (i.e., transformer T), converter C, and power generation equipment (such as photovoltaic PV, wind turbine WT, etc.) connected in sequence. Each branch also converges to the grid connection point M. The new energy site, reactive compensation device, and grid-forming unit are connected to the grid through the external impedance branch; the external impedance branch is the electrical path connecting the new energy site, reactive compensation device, grid-forming unit and other equipment with the external grid. The electrical path includes the transmission line and main transformer between the grid connection point M and the grid. To facilitate subsequent analysis and calculation, the transmission line and main transformer between the grid connection point M and the grid can be equivalent to the following: Figure 2 The equivalent resistance shown and equivalent reactance .

[0059] In the grid-connected planning of a new energy station, a designer can determine the number of new energy stations and the related parameters (such as the rated voltage, resistance, and reactance of the equipment, and the equipment capacity) of each device (such as a transformer, a converter, a line, and a power generation device) in the station according to actual needs. Then, the first configuration capacity of a reactive power compensation device for the new energy station is determined according to the known planning of the new energy station. The industry standards "GB / T 19963.1-2021 Technical Regulation for Wind Power Plant Integration into Power System: Part 1: Onshore Wind Power" and "GB / T 19964-2024 Technical Regulation for Photovoltaic Power Plant Integration into Power System" require that the reactive power capacity configured by a wind power plant / photovoltaic power plant should be able to compensate for the inductive and capacitive reactive power of the station line and transformer, so the capacity of the reactive power compensation device should depend on the reactive power loss of the new energy station.

[0060] Therefore, for each new energy station connected to a weak grid, each device (such as a transformer, a converter, and a line) in the new energy station can be regarded as a separate node, and then the reactive power loss of each node is calculated according to the voltage corresponding to the node (i.e., the node voltage). Then, the first configuration capacity of the reactive power compensation device is determined according to the reactive power loss of all nodes. For example, the reactive power losses of all nodes can be added up, and the added value can be taken as the first configuration capacity, or a certain amount of redundant reactive power compensation can be configured based on the added value, and the first configuration capacity can be increased.

[0061] In the related art, the approximate calculation of the reactive power loss ignores the effective transmission capacity in the actual circuit and the line voltage drop caused thereby. It is found through multiple simulation verifications that the error between the approximate calculation method of the reactive power loss and the actual loss is small under strong grid conditions, but there is a relatively obvious deviation under weak grid conditions. Therefore, when the reactive power loss of each node is calculated according to the voltage of each node, the voltage of each node needs to be corrected to determine a more accurate reactive power loss. In a feasible implementation manner, steps S80-S90 are further included before step S100 to correct the voltage of each node.

[0062] In step S80, the rated node voltage corresponding to each node is obtained.

[0063] In step S90, for each node, the rated node voltage corresponding to the node is corrected based on the circuit characteristic parameters of the external impedance branch to obtain the node voltage.

[0064] It can be understood that, under the weak network condition, the grid-connected point voltage of the new energy station deviates from the rated voltage, so when the reactive power loss of each node is calculated, the calculation value deviates greatly from the actual loss value, and therefore the voltage of each node in the new energy station needs to be corrected. The rated node voltage corresponding to each node is generally set based on the design parameters of the equipment, the operation requirements, and the standards of the power system, and is a known quantity. On this basis, considering the influence of line voltage drop, the rated node voltage of each node can be corrected by using the circuit characteristic parameters of the external impedance branch to obtain the node voltage for reactive power loss calculation. In a feasible implementation manner, step S90 can include correcting the rated node voltage based on calculation formula one to obtain the node voltage.

[0065] The calculation formula one is: ;

[0066] wherein, is the node voltage, is the rated node voltage, is the rated current of the external impedance branch, is the equivalent resistance of the external impedance branch, is the equivalent reactance of the external impedance branch; by substituting the rated node voltage of each node into the above calculation formula one, the node voltage of each node after correction (such as the node voltage of the transformer node , the node voltage of the line node , and the node voltage of the converter node ) can be obtained. On this basis, the reactive power loss calculation can be performed based on the corrected node voltage. Specifically, step S200 can include determining the reactive power loss of each node based on calculation formula two and the node voltage corresponding to each node.

[0067] The calculation formula two is: ;

[0068] wherein, is the reactive power loss of the transformer node, is the reactive power loss of the line node, is the reactive power loss of the converter node, is the rated apparent power of the transformer node, is the rated apparent power of the line node, is the transformer reactance, is the line reactance, is the line-to-ground capacitance, is the equivalent impedance of the converter filter capacitance, is the node voltage of the transformer node, is the node voltage of the line node, The node voltage is the node voltage of the converter node. Based on the above calculation formula two, the reactive power loss of each node in each new energy station can be determined. Then, the total reactive power loss of all new energy stations can be obtained by summing all the calculated reactive power losses, and the reactive power loss summation calculation formula is: ; The total reactive power loss of the new energy station is the total reactive power loss of the new energy station. According to the total reactive power loss, the first configuration capacity corresponding to the reactive power compensation device can be determined.

[0069] By means of voltage correction, the reactive power loss of the new energy station under weak grid condition can be more accurately estimated, so as to improve the voltage level of the grid-connected point and configure a first configuration capacity more suitable for the actual grid strength. It should be noted that, since the error between the approximate calculation method of reactive power loss and the actual loss is small under strong grid condition, in order to simplify the overall calculation process, the voltage of each node can not be corrected, and the rated node voltage corresponding to each node can be directly obtained for reactive power loss calculation.

[0070] In addition, in order to realize the optimal configuration of the reactive power compensation device, after the initial first configuration capacity is determined according to the reactive power loss calculated based on the node voltage, iteration optimization can be performed based on the first configuration capacity to determine the final first configuration capacity. In a feasible implementation manner, after step S200, the above new energy station grid-connected configuration method can further include steps A100-A200 for determining the optimal first configuration capacity according to a preset power factor:

[0071] Step A100, predicting whether the power factor of the grid-connected point after the reactive power compensation device operates based on the first configuration capacity is less than the preset power factor.

[0072] Step A200, in the case that the power factor is less than the preset power factor, updating the first configuration capacity based on a preset reactive power compensation increment, and returning to execute step A100 until the power factor is greater than or equal to the preset power factor.

[0073] It can be understood that the power factor is an important indicator for measuring the efficiency of power utilization in the power system. In order to effectively compensate for reactive power and achieve high energy utilization, reduce energy costs and equipment burden, the designer can determine a preset power factor according to the actual design requirements. The power factor can be set to a larger value (such as 0.98). Then it is predicted whether the power factor of the power system at the point of common coupling after the operation of the reactive power compensation device based on the initial first configuration capacity is less than the preset power factor. If it is less than the preset power factor, a preset reactive power compensation increment (such as increasing the first configuration capacity by 2%) can be added to the first configuration capacity as a new first configuration capacity, and then returning to step A100, the power factor of the point of common coupling under this configuration is estimated again until the final power factor is greater than or equal to the preset power factor, and the first configuration capacity corresponding to the power factor is taken as the final first configuration capacity of the reactive power compensation device.

[0074] Step S300, predicting whether the short-circuit ratio of the point of common coupling of the power system after the operation of the reactive power compensation device based on the first configuration capacity is less than the preset short-circuit ratio.

[0075] Step S400, in the case that the short-circuit ratio of the point of common coupling is less than the preset short-circuit ratio, increasing the second configuration capacity of the grid-forming unit until the predicted short-circuit ratio of the point of common coupling after the operation of the grid-forming unit based on the second configuration capacity is greater than or equal to the preset short-circuit ratio.

[0076] Step S500, determining the new energy station grid connection configuration result based on the first configuration capacity and the second configuration capacity.

[0077] Specifically, the preset short-circuit ratio is a preset value determined by the designer according to the new energy station grid connection design standard, and the short-circuit ratio of the point of common coupling can measure the grid connection stability of the new energy station, and increasing the capacity of the grid-forming unit can effectively improve the short-circuit ratio of the point of common coupling. Therefore, a preset short-circuit ratio can be determined according to the actual design requirements, and then the capacity optimization of the grid-forming unit is performed to determine the optimal second configuration capacity of the grid-forming unit that can meet the preset short-circuit ratio, so as to improve the grid connection stability of the new energy station.

[0078] It should be noted that the grid-forming unit usually has a rated capacity, which can be regarded as the initial second configuration capacity of the grid-forming unit. On the basis of the first configuration capacity determined in the foregoing and the initial second configuration capacity, the power system can be run by using power simulation software to predict whether the point-of-connection short-circuit ratio under this configuration is less than the preset short-circuit ratio; if the point-of-connection short-circuit ratio is less than the preset short-circuit ratio, it indicates that the second configuration capacity of the grid-forming unit cannot yet meet the grid-connection stability design requirement, and therefore the second configuration capacity of the grid-forming unit needs to be increased (for example, by 5% of the rated capacity) again until the finally predicted point-of-connection short-circuit ratio is greater than or equal to the preset short-circuit ratio. In a feasible implementation manner, the calculation formula three of the point-of-connection short-circuit ratio is: ;

[0079] wherein, is the point-of-connection short-circuit ratio, n is the total number of new energy stations in the power system, is the short-circuit capacity provided by the power grid to the i th new energy station, is the active power injected by the i th new energy station, is the active power injected by the j th new energy station, is the mutual impedance between the i th new energy station and the j th new energy station under the current configuration, is the self-impedance of the i th new energy station under the current configuration.

[0080] In combination with the finally determined first configuration capacity of the reactive power compensation device and the second configuration capacity of the grid-forming unit, the grid-connection configuration result of the new energy station can be determined for the reference of actual grid-connection construction of the new energy station.

[0081] The new energy station grid-connection configuration method provided in the embodiments can determine the corresponding reactive power loss according to the voltage of each node in the grid-connection construction of the new energy station, and adaptively configure the reactive power compensation device according to the reactive power loss. The reactive power compensation device can compensate the reactive power, which can improve the voltage of the point of connection and reduce the capacity requirement of the grid-forming unit on the system, thereby effectively reducing the grid-connection construction cost of the new energy station. The power system stability and economy can be considered by the collaborative optimization configuration of the reactive power compensation device and the grid-forming unit.

[0082] Exemplarily, in order to help understand the implementation process of the new energy station grid-connection configuration method of the embodiments, please refer to Figure 3 , Figure 3 A brief flowchart of a new energy station grid-connection configuration method is provided, and specifically:

[0083] For example, Figure 3As shown, the parameters of each device capacity, box transformer, main transformer, line, etc. of the new energy station and the preset short-circuit ratio of the new energy station can be determined according to the grid-connected construction demand of the new energy station ; and the foregoing data is input into the new energy station grid-connected device for processing. The new energy station grid-connected device can correct the voltage of each node of the new energy station by using the calculation formula one, and determine the reactive power loss of each device in the new energy station under the rated power by using the calculation formula two and the corrected node voltage, and determine the first configuration capacity (i.e. the reactive power compensation capacity) of the reactive power compensation device according to all the reactive power losses. And calculate the power factor cosθ of the grid-connected point under the current configuration capacity; if cosθ < 0.98, then increase the reactive power compensation capacity by 2% based on the foregoing first configuration capacity, and return to calculate the power factor of the grid-connected point under the current configuration, until the cosθ corresponding to the first configuration capacity is ≥ 0.98.

[0084] When cosθ ≥ 0.98, it means that the optimization calculation of the first configuration capacity is completed, and the initial short-circuit ratio of the new energy station under the rated operating condition of the current system architecture after the reactive power compensation device is operated based on the first configuration capacity can be further predicted If , it can be determined that the initial short-circuit ratio corresponding to the rated capacity of the grid-forming unit is the optimal second configuration capacity of the grid-forming unit, and the foregoing optimal first configuration capacity, the current grid-connected point short-circuit ratio and the corresponding second configuration capacity are output as the grid-connected configuration result of the new energy station; if , the grid-forming unit with 5% rated capacity is added, and then the grid-connected point short-circuit ratio of the new energy station after the capacity of the grid-forming unit is increased is predicted again (m represents the number of cycles) until the grid-connected point short-circuit ratio ; and the foregoing first configuration capacity, the current grid-connected point short-circuit ratio and the corresponding second configuration capacity are output as the final grid-connected configuration result of the new energy station.

[0085] It should be noted that the prediction and calculation of the short-circuit ratio of the grid-connected point can be based on power simulation software. Generally, the automatic operation program of the power system simulation software can be used to write a loop judgment code containing automatic operation and automatic calculation: first, input the relevant parameters (such as device capacity, device equivalent impedance, line impedance, etc.) under the current power system topology, and write the calculation formula three mentioned in the foregoing embodiments in the automatic operation program, then set to increase the capacity of the grid-forming unit by 5%, and automatically run the simulation model. Through the simulation results, the current configuration of the new energy station branch current, voltage, and corresponding mutual impedance and self-impedance between the new energy stations can be determined. By means of the simulation software to build and run the simulation model of the power system, the mutual impedance and self-impedance involved in the calculation formula three can be automatically updated, and the corresponding short-circuit ratio of the grid-connected point after each increase in the capacity of the grid-forming unit can be calculated .

[0086] Based on the above examples, it can be seen that the new energy station grid connection configuration method provided by the present application is a method for coordinated planning of reactive power compensation devices and grid-forming units in a weak grid scenario. A double-layer optimization model can be designed on a power system simulation platform based on the topology of the line. The upper layer realizes dynamic optimization configuration of the reactive power compensation device by constructing an improved reactive power loss calculation model (i.e., by optimizing the node voltage to improve the reactive power loss calculation method), and determines the final first configuration capacity of the reactive power compensation device according to the preset power factor. The lower layer establishes a target constraint condition based on short-circuit ratio sensitivity analysis, and uses self-optimizing iteration to obtain the optimized ratio of the capacity of the grid-forming unit. The new energy station grid connection configuration method of the present application integrates the power factor and the grid-connected point short-circuit ratio constraint conditions into a double-layer optimization framework. Under the premise of ensuring that the new energy station grid-connected point meets the safe operation, the capacity configuration of the reactive power compensation device and the grid-forming unit is optimized, and finally the system stability and the station economy are considered.

[0087] It should be noted that the above examples are only for understanding the present application and do not constitute a limitation on the new energy station grid connection configuration method of the present application. Based on this technical concept, more forms of simple transformation are within the protection scope of the present application.

[0088] The present application also provides a new energy station grid connection configuration device, please refer to Figure 4 The new energy station grid connection configuration device can be used in a power system, which includes at least one new energy station, a reactive power compensation device, a grid-forming unit, and a power grid. The new energy station, the reactive power compensation device, and the grid-forming unit are connected to a grid-connected point and connected to the power grid through an external impedance branch. The new energy station grid connection configuration device includes:

[0089] The reactive loss determination module 10 is configured to determine the reactive loss of each node in the new energy station based on the node voltage of each node in the new energy station for each new energy station accessing a weak network, wherein the node is a transformer node, a converter node or a line node.

[0090] The first configuration capacity determination module 20 is configured to determine the first configuration capacity of the reactive power compensation device based on all the reactive losses.

[0091] The grid connection point short-circuit ratio prediction module 30 is configured to predict whether the grid connection point short-circuit ratio of the power system is less than the preset short-circuit ratio after the reactive power compensation device operates based on the first configuration capacity.

[0092] The second configuration capacity determination module 40 is configured to increase the second configuration capacity of the grid-forming unit until the predicted grid connection point short-circuit ratio is greater than or equal to the preset short-circuit ratio after the grid-forming unit operates based on the second configuration capacity in the case that the grid connection point short-circuit ratio is less than the preset short-circuit ratio.

[0093] The grid connection configuration result determination module 50 is configured to determine the grid connection configuration result of the new energy station based on the first configuration capacity and the second configuration capacity.

[0094] The new energy station grid connection configuration device provided in the present application adopts the new energy station grid connection configuration method in the above embodiments, and can solve the technical problem that the system stability and economy cannot be considered in the related art new energy station grid connection construction. Compared with the related art, the new energy station grid connection configuration device provided in the present application has the same beneficial effects as the new energy station grid connection configuration method provided in the above embodiments, and the other technical features in the new energy station grid connection configuration device are the same as the features disclosed in the above embodiments, which will not be described herein.

[0095] The present application provides a new energy station grid connection configuration device, which comprises at least one processor and a memory in communication connection with the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the new energy station grid connection configuration method in the above embodiment one.

[0096] Reference will be made to the following description Figure 5 which shows a structural schematic diagram of a new energy station grid connection configuration device suitable for implementing the embodiments of the present application. The new energy station grid connection configuration device in the embodiments of the present application can include but is not limited to mobile terminals such as notebook computers, PDAs (Personal Digital Assistant: personal digital assistants), PADs (Portable Application Description: tablet computers) and the like, and fixed terminals such as desktop computers and the like.Figure 5 The illustrated new energy plant grid-connection configuration device is merely an example and should not bring any limitation to the function and use range of the embodiments of the present application.

[0097] As shown in Figure 5 The new energy plant grid-connection configuration device can include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.) that can perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) 1002 or loaded from a storage device 1003 into a random access memory (RAM) 1004. Various programs and data required for the operation of the new energy plant grid-connection configuration device are also stored in the RAM 1004. The processing device 1001, the ROM 1002, and the RAM 1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, etc.; an output device 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; the storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the new energy plant grid-connection configuration device to communicate with other devices wirelessly or by wire to exchange data. Although the new energy plant grid-connection configuration device with various systems is shown in the figure, it should be understood that all the illustrated systems are not required to be implemented or possessed. More or fewer systems can be alternatively implemented or possessed.

[0098] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program codes for executing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network through the communication device, or installed from the storage device 1003, or installed from the ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the methods of the embodiments disclosed in the present application are performed.

[0099] The new energy station grid connection configuration device provided in the application adopts the new energy station grid connection configuration method in the above embodiment, and can solve the technical problem that system stability and economy cannot be considered in new energy station grid connection construction in the related art. Compared with the related art, the new energy station grid connection configuration device provided in the application has the same beneficial effects as the new energy station grid connection configuration method provided in the above embodiment, and other technical features in the new energy station grid connection configuration device are the same as the features disclosed in the previous embodiment method, and thus are not described herein.

[0100] It should be understood that parts of the present application can be realized by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0101] The above is merely specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0102] The present application provides a computer readable storage medium having computer readable program instructions (i.e. computer programs) stored thereon, the computer readable program instructions being used to execute the new energy station grid connection configuration method in the above embodiment.

[0103] The computer readable storage medium provided in the application may be, for example, a U disk, but is not limited to an electric, magnetic, optical, electromagnetic, infrared, or semiconductor system or device, or any combination thereof. More specific examples of the computer readable storage medium may include, but are not limited to, an electric connection with one or more conductive wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the embodiment, the computer readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system or device. The program code contained on the computer readable storage medium can be transmitted by any suitable medium, including but not limited to an electric wire, an optical cable, an RF (Radio Frequency), and the like, or any suitable combination thereof.

[0104] The computer readable storage medium described above may be contained in a new energy station grid connection configuration device, or may exist separately and not be assembled into the new energy station grid connection configuration device.

[0105] The computer readable storage medium described above carries one or more programs, when the one or more programs are executed by the new energy station grid connection configuration device, the new energy station grid connection configuration device determines the reactive power loss of each node in the new energy station based on the node voltage of each node in the new energy station for each new energy station accessing a weak grid; the node is a transformer node, a converter node or a line node; determines the first configuration capacity of the reactive power compensation device based on all the reactive power losses; predicts whether the short circuit ratio of the grid connection point of the power system is less than the preset short circuit ratio after the reactive power compensation device operates based on the first configuration capacity; in the case that the short circuit ratio of the grid connection point is less than the preset short circuit ratio, the second configuration capacity of the network-forming unit is increased until the predicted short circuit ratio of the grid connection point is greater than or equal to the preset short circuit ratio after the network-forming unit operates based on the second configuration capacity; determines the new energy station grid connection configuration result based on the first configuration capacity and the second configuration capacity.

[0106] Computer program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0107] The flow diagrams and the block diagrams in the drawings are illustrations of architectures, functionalities, and operations of possible implementations of methods and computer program products according to various embodiments presented in this application. In this regard, each block in the flow diagrams or block diagrams can represent a module, a segment, or a portion of code, which comprises one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks may

[0108] The modules involved in the embodiments of the present application can be implemented in the form of software or in the form of hardware. In some cases, the name of the module does not constitute a limitation on the module itself.

[0109] The readable storage medium provided by the present application is a computer readable storage medium, which stores computer readable program instructions (i.e., a computer program) for executing the new energy station grid connection configuration method described above, and can solve the technical problem that the new energy station grid connection construction in the related art cannot take into account system stability and economy. Compared with the related art, the computer readable storage medium provided by the present application has the same beneficial effects as the new energy station grid connection configuration method provided by the above embodiments, and will not be described here.

[0110] The application further provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the new energy station grid connection configuration method as described above.

[0111] The computer program product provided by the application can solve the technical problem that system stability and economy cannot be considered in new energy station grid connection construction in the related art. Compared with the related art, the beneficial effects of the computer program product provided by the application are the same as those of the new energy station grid connection configuration method provided by the above-described embodiments, and are not described herein.

[0112] The above only describes some embodiments of the application, and does not limit the patent scope of the application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like made by using the content of the specification and drawings within the technical concept of the application is included in the patent protection scope of the application.

Claims

1. A method for grid-connected configuration of a new energy station, characterized in that, The application relates to a power system, which comprises at least one new energy station, a reactive power compensation device, a grid-forming unit and a power grid, wherein the new energy station, the reactive power compensation device and the grid-forming unit are connected to a point of common coupling (PCC) and connected to the power grid through an external impedance branch. The method for configuring the new energy station to be connected to the grid comprises the following steps: For each new energy station connected to a weak grid, the reactive power loss of each node in the new energy station is determined based on the node voltage of the node. Based on all the reactive power losses, the first configuration capacity of the reactive power compensation device is determined. It is predicted whether the short-circuit ratio (SCR) of the PCC of the power system is less than a preset SCR after the reactive power compensation device operates based on the first configuration capacity. In the case that the SCR of the PCC is less than the preset SCR, the second configuration capacity of the grid-forming unit is increased until the predicted SCR of the PCC is greater than or equal to the preset SCR after the grid-forming unit operates based on the second configuration capacity. Based on the first configuration capacity and the second configuration capacity, the configuration result of the new energy station connected to the grid is determined. Before the step of determining the reactive power loss of each node based on the node voltage of each node in the new energy station, the method further comprises the following steps: The rated node voltage corresponding to each node is obtained. For each node, the rated node voltage corresponding to the node is corrected based on the circuit characteristic parameter of the external impedance branch to obtain the node voltage. After the step of determining the first configuration capacity of the reactive power compensation device based on all the reactive power losses, the method further comprises the following steps: It is predicted whether the power factor of the PCC is less than a preset power factor after the reactive power compensation device operates based on the first configuration capacity. In the case that the power factor is less than the preset power factor, the first configuration capacity is updated based on a preset reactive power compensation increment, and the step of predicting whether the power factor of the PCC is less than a preset power factor after the reactive power compensation device operates based on the first configuration capacity is performed again until the power factor is greater than or equal to the preset power factor. The first configuration capacity corresponding to the power factor is determined as the final first configuration capacity of the reactive power compensation device.

2. The method of claim 1, wherein, The step of correcting the rated node voltage corresponding to the node based on the circuit characteristic parameter of the external impedance branch to obtain the node voltage comprises the following steps: The rated node voltage is corrected based on a calculation formula one to obtain the node voltage. The calculation formula is: ; wherein, is the node voltage, is the rated node voltage, is the rated current of the external impedance branch, is the equivalent resistance of the external impedance branch, is the equivalent reactance of the external impedance branch.

3. The method of claim 2, wherein, The step of determining the reactive power loss of each node based on the node voltage of each node in the new energy station comprises the following steps: The reactive power loss of each node is determined based on a calculation formula two and the node voltage corresponding to each node. The calculation formula two is: ; wherein, Qtr is the reactive loss of the transformer node, Ql is the reactive loss of the line node, Qcv is the reactive loss of the converter node, Sctr is the rated apparent power of the transformer node, Scl is the rated apparent power of the line node, Xtr is the transformer reactance, Xl is the line reactance, Cgl is the line-to-ground capacitance, Zf is the filter capacitance equivalent impedance of the converter, Vtr is the node voltage of the transformer node, Vl is the node voltage of the line node, Vcv is the node voltage of the converter node.

4. The new energy station grid-connected configuration method according to any one of claims 1 to 3, characterized in that, The calculation formula three of the point of common coupling short-circuit ratio is: ; wherein, is the short-circuit ratio of the point of common coupling, n is the total number of new energy stations in the power system, is the short-circuit capacity provided by the power grid to the i-th new energy station, is the active power injected by the i-th new energy station, is the active power injected by the j-th new energy station, is the mutual impedance between the i-th new energy station and the j-th new energy station under the current configuration, is the self-impedance of the i-th new energy station under the current configuration.

5. A new energy station grid-connected configuration device, characterized in that, The application relates to a power system, which comprises at least one new energy station, a reactive power compensation device, a grid-forming unit and a power grid, wherein the new energy station, the reactive power compensation device and the grid-forming unit are connected to a point of common coupling (PCC) and connected to the power grid through an external impedance branch. The device for configuring the new energy station to be connected to the grid comprises the following steps: The reactive loss determination module is configured to determine the reactive loss of each node in the new energy station based on the node voltage of each node in the new energy station, wherein the node is a transformer node, a converter node, or a line node. The first configuration capacity determination module is configured to determine the first configuration capacity of the reactive compensation device based on all the reactive losses. The grid connection point short-circuit ratio prediction module is configured to predict whether the grid connection point short-circuit ratio of the power system is less than a preset short-circuit ratio when the reactive compensation device operates based on the first configuration capacity. The second configuration capacity determination module is configured to increase the second configuration capacity of the grid-forming unit until the predicted grid connection point short-circuit ratio is greater than or equal to the preset short-circuit ratio when the grid-forming unit operates based on the second configuration capacity. The grid connection configuration result determination module is configured to determine the grid connection configuration result of the new energy station based on the first configuration capacity and the second configuration capacity. The new energy station grid connection configuration device is further configured to obtain the rated node voltage corresponding to each node, and correct the rated node voltage corresponding to each node based on the circuit characteristic parameters of the external impedance branch to obtain the node voltage. The new energy station grid connection configuration device is further configured to predict whether the power factor of the grid connection point is less than a preset power factor when the reactive compensation device operates based on the first configuration capacity, and update the first configuration capacity based on a preset reactive compensation increment when the power factor is less than the preset power factor, and return to the step of predicting whether the power factor of the grid connection point is less than the preset power factor when the reactive compensation device operates based on the first configuration capacity until the power factor is greater than or equal to the preset power factor, and determine the first configuration capacity corresponding to the power factor as the final first configuration capacity of the reactive compensation device.

6. A new energy plant grid-connected configuration device, characterized in that, The device includes a memory, a processor, and a computer program stored on the memory and executable on the processor, and the computer program is configured to implement the steps of the new energy station grid connection configuration method according to any one of claims 1 to 4.

7. A storage medium, characterized by The storage medium is a computer readable storage medium, and the storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the new energy station grid connection configuration method according to any one of claims 1 to 4.

8. A computer program product, characterised in that, The computer program product includes a computer program, and the computer program is executed by a processor to implement the steps of the new energy station grid connection configuration method according to any one of claims 1 to 4.

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