Transient reactive power equipment capacity configuration calculation method, equipment and storage medium

Abstract

The invention discloses a transient reactive power equipment capacity configuration calculation method, equipment and a storage medium, and the method comprises the steps: considering a system main grid structure and the characteristics of a conventional DC LCC converter during a transient state, determining the transient reactive power demand of a system region, considering the data of the system main grid structure, the transient reactive power demand point and the test and statistical data of the capacities of different actual installation points, and calculating the capacity configuration of the transient reactive power equipment. And obtaining a conversion formula of the capacity configuration of the transient reactive power equipment between different stations, and giving the capacity required by the configuration of the transient reactive power equipment of the different stations in the region. The method can calculate the regional transient reactive power demand during the fault period according to the system characteristics, carries out the capacity deduction of peripheral possible installation sites, is suitable for the transient reactive power equipment installation of a domestic DC dense feed-in region, is suitable for the transient reactive power equipment capacity determination of the project feasibility analysis at the initial stage of construction, and is suitable for the installation of the transient reactive power equipment. The method is more suitable for comparison and selection among different installation sites during a project argumentation decision-making period, and is wide in application range; the formula is reasonably simplified based on statistical data and test data, and simplicity, convenience and rapidness are achieved.

Description

Technical Field

[0001] This invention relates to the field of transient reactive power capacity configuration technology, specifically to a transient reactive power equipment capacity configuration calculation method, equipment, and storage medium. Background Technology

[0002] With the continuous development of new power systems and the expansion of renewable energy installed capacity, and given the inverse distribution of renewable energy and load, large-scale conventional DC dense feeds into load centers have been implemented in recent years to ensure the transmission and consumption of new energy, while reducing the proportion of conventional voltage. As the proportion of power electronic equipment gradually approaches the system stability limit, the problem of transient reactive power deficiency after faults has become increasingly prominent due to the dense feeds of conventional DC into load centers. During the summer peak of 2024, the Sichuan Debao DC power grid experienced power curtailment at the receiving end due to DC feeds and transient reactive power deficiency. To ensure stable system operation and full-power DC power reception, a large number of grid-type devices were constructed to provide substantial transient reactive power support. Meanwhile, provinces such as Jiangsu and Zhejiang also face transient reactive power deficiency to varying degrees. For such problems, the best approach is generally to install transient reactive power equipment at sites with the deepest voltage drops, the most difficult recovery, and the weakest grid structure. However, with the continuous development of urban centers, increasingly scarce land resources, and increasingly compact substation designs, it is often difficult to directly install transient reactive power equipment at the most effective sites. Therefore, how to perform transient reactive power demand assessment and calculation after a regional fault based on the control characteristics of conventional DC feeders after a fault, and how to perform capacity calculation and conversion for transient reactive power compensation equipment installed at non-optimal sites, have become urgent problems to be solved.

[0003] Previous studies on regional reactive power configuration requirements have largely focused on optimizing reactive power configuration under steady-state scenarios, conducting some power flow analysis, and studying how to configure the reactive power system to minimize losses. Some studies have also considered dynamic reactive power optimization configuration. However, none of these studies have taken into account practical engineering challenges such as the inability to install optimal nodes, reactive power capacity conversion between non-optimal and optimal nodes, and the quantification of regional reactive power demand. Literature such as "Reactive Power Compensation Device Capacity Optimization Configuration Strategy Based on Dynamic Load Characteristics," "Research on Reactive Power Compensation Device Location and Capacity Determination Considering Multiple Operating Scenarios and Optimization Objectives in New Energy Power Systems," and "Substation Reactive Power Optimization Considering Capacitor Operation Regulation Cost" have considered grid constraints and minimizing losses or reactive power equipment switching. They have also taken into account the characteristics of power electronic equipment in new power systems to some extent and have provided many useful conclusions. However, these studies are only applicable to research on static reactive power configuration. The literature, "Optimization Configuration Method for Reactive Power Compensation Devices in the Receiving End Power Grid Considering Post-Fault Power Transfer" and "Study on Optimal Configuration of Dynamic Reactive Power Compensation for AC and DC Power Network," considers weak node assessment, power electronic device characteristics, and relative electrical distance to optimize and select the installation location of dynamic reactive power. However, it does not provide a precise calculation method for dynamic reactive power installation capacity, nor does it consider situations where some nodes cannot be installed in actual engineering projects, nor does it address how to simplify the installation configuration capacity between different nodes. For reactive power failures in DC systems, a specific analysis can be performed based on the DC system control principles.The literature, including "Safety Margin Assessment and Suppression Method for Successive Commutation Failure for Multi-infeed High Voltage Direct Current Systems Under Fault of Weak Receiving-End Grid" and "Identification of the Weak Areas of Simultaneous Commutation Failure for Multi-infeed DC System during Power System Restoration," provides a relatively detailed theoretical analysis of commutation failure in conventional DC systems. It conducts theoretical analyses of reactive power or voltage in multi-infeed high-voltage direct current systems, considering weak nodes and areas within the receiving-end grid, and thus has good reference value. However, it lacks quantitative analysis of regional dynamic reactive power demand and quantitative conversion of reactive power demand under different installation site conditions. Therefore, it is not applicable to the calculation of installation capacity and scheme comparison in different scenarios in actual engineering projects. Summary of the Invention

[0004] This invention proposes a method, device, and storage medium for calculating transient reactive power equipment capacity configuration, overcoming the shortcomings of existing analysis methods. It provides a new method for calculating dynamic reactive power capacity configuration in power systems, gives a quantitative calculation method for regional dynamic reactive power demand, and provides a conversion of dynamic reactive power configuration demand between weak nodes and installation nodes. It is used for calculating the installation capacity demand of dynamic reactive power equipment in new power systems and for capacity configuration conversion between different sites. It provides transient reactive power demand calculation and conversion in practical applications and also facilitates early comparison and selection.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for calculating the capacity configuration of transient reactive power equipment involves performing the following steps using computer equipment. (1) For lines that are found to be transiently unstable after a fault, select the weak nodes as the chain structures on both sides of the line with longer chain structures. For the weak nodes, the nodes connected to the faulty line are disconnected and extended outward to the large power source, the second DC power source, the low-voltage side of the upper-level substation, or the area power grid that is more than or equal to 5 nodes away from the weak nodes.

[0006] (2) Analyze and calculate the reactive power consumption during the transient fault of the system. After the system fault, select the power grid in the area where the plant is located, which is relatively weak on both sides of the fault, and perform reactive power demand calculation. Consider the reactive power absorption caused by the failure of the converter to recover, the charging power of the disconnected line and the reactive power supply, and the transient reactive power regulation capability that the unit can provide.

[0007] The principle is that, considering the static reactive power compensation of ordinary substation nodes, which is configured to compensate for the reactive power consumption of regional loads, main transformers, and lines, it should be configured in a balanced manner; the reactive power equipment configured at converter nodes is mainly to compensate for the converter demand. During a fault, the transient reactive power support provided by conventional units can make up for the increased reactive power demand of the converter nodes; and after a fault, disconnecting the line will result in the loss of the line's ground capacitance and the reactive power delivered by the line under normal operating conditions.

[0008] (1) in, The reactive power absorbed by the i-node converter and its corresponding compensation during fault conditions, and the reactive power compensation reduced within the site where the converter is located, are included in the transient reactive power of the unit by the synchronous condenser configured with the converter.

[0009] (2) In the formula This is the change in AC side voltage of the valve group (i.e., the highest value of AC voltage recovery, approximately considered as the difference between 1.0 pu and the converter recovery voltage of 0.8 pu). The rated voltage on the AC side of the valve assembly. This is the actual voltage on the AC side of the valve assembly. This represents the per-unit value of the AC side voltage of the valve assembly. For the short-circuit capacity of the AC node on the valve assembly side, This refers to the original reactive power compensation capacitor value of the converter station. For corresponding reactive power compensation The rated compensation capacity. It is easy to see. The calculation formula is about The minimum point of the convex function is located at Considering therefore Meanwhile, considering that converter recovery requires a valve terminal voltage higher than 0.8 pu, therefore... Within the range, For about The decreasing function, therefore, is taken as the minimum after restoration. It can be calculated, therefore Take 0.8.

[0010] in To disconnect the reactive power value of the power flow on the line, The rated charging power for disconnecting the line.

[0011] (3) In the formula, C is the distributed capacitance value of the line.

[0012] in Let be the regulating capacity of the unit at node j, and be the difference between the maximum dynamic non-functional capacity and the static non-functional capacity after a fault.

[0013] (4) In the formula This refers to the generator terminal voltage. The q-axis electromotive force under strong excitation. This represents the reactive power output value before the unit malfunctions (capacitive values ​​are positive). For d-axis coaxial reactance, The maximum unloaded capacity of the unit after a failure can be obtained through parameter analysis calculation or simulation experiment.

[0014] (3) Select and retain the proposed installation site and the weakest power station. Keep the proposed installation site and the weakest power station to simplify the network structure of other systems. Only retain the proposed installation site and the weakest power station. The power grids on both sides are equivalent to the Thevenin model, and the inter-site is equivalent to the mutual impedance model. Extract the per-unit value of the mutual impedance between the two sites, with 100MVA as the reference.

[0015] (4) Convert the transient reactive power demand of the weak point into the transient reactive power demand of the proposed installation site: (5) in It is a constant, obtained through fitting. (6) The mutual impedance between the weak substation and the substation to be installed.

[0016] (5) Calculate the rated capacity of the equipment at the proposed installation point. : (7) In the formula, N is the rated transient overcurrent multiple of the equipment to be installed.

[0017] In another aspect, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0018] In another aspect, the present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described above.

[0019] As can be seen from the above technical solution, this invention relates to a method for calculating the capacity configuration of transient reactive power equipment, aiming to provide a practical calculation method applicable to the installation of transient reactive power compensation capacity at different sites within a region. The method mainly includes: considering the main grid structure of the system and the characteristics of conventional DC LCC converters during transient periods, determining the transient reactive power demand of the system region; considering the main grid data of the system, experimental and statistical data on the transient reactive power demand points and the capacities of different actual installation points, obtaining conversion formulas for the configuration of transient reactive power equipment capacity between different sites, and providing the required capacity of configured transient reactive power equipment at different sites within the region. This method can calculate the transient reactive power demand of the region during a fault based on system characteristics and extrapolate the capacity of possible installation sites in the surrounding area. It is applicable to the installation of transient reactive power equipment in densely fed DC areas in China, and also applicable to the determination of transient reactive power equipment capacity in the feasibility analysis of projects in the early stages of construction. It is even more suitable for comparing and selecting different installation sites during project demonstration and decision-making, and has a wide range of applications. The formula is reasonably simplified based on statistical and experimental data, making it more convenient and faster.

[0020] Compared with the prior art, the advantages of the present invention are as follows: (1) The proposed transient reactive power demand calculation takes into account the increased reactive power consumption of regional converters and corresponding power plant equipment, as well as the reduced reactive power compensation of corresponding fault lines and the reactive power flow provided by fault lines under normal conditions and the dynamic reactive power capacity that conventional units can provide. Because the calculation is simple and does not require professional analysis, it is suitable for engineers of various specialties to convert and evaluate projects, and is suitable for calculating the installation capacity of transient reactive power support equipment at different sites with different physical conditions in new power systems.

[0021] (2) The calculation method takes into account the relationship between mutual impedance to weak points and transient reactive power demand. A specific power system analysis experiment was conducted. Based on the experiment and fitting, the correlation formula between mutual impedance and transient reactive power demand was obtained, which ensured the accuracy of the calculation results.

[0022] In summary, the transient reactive power equipment capacity configuration calculation method proposed in this invention can accurately calculate the transient reactive power equipment capacity configuration and the demand conversion between sites under the feasibility or economic requirements of a project, providing reference and suggestions for transient reactive power equipment capacity configuration and comprehensive decision-making on optimal installation sites. Attached Figure Description Figure 1 These are the installation capacity requirement curves under different mutual resistance conditions in the embodiments of the present invention; Figure 2 This is a flowchart illustrating the implementation of this invention; Figure 3 This is a regional power grid topology diagram according to an embodiment of the present invention; Figure 4 This is a simplified diagram of the regional installed capacity conversion power grid according to an embodiment of the present invention; Figure 5 This is an embodiment of the invention showing the impact of the same node installation on the bus voltage of node 2. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0024] A method for calculating the capacity configuration of transient reactive power equipment according to an embodiment of the present invention is as follows: Figure 2 As shown, it includes the following steps: S1. For lines where transient instability is calculated after a fault, select the longest chain structure on both sides of the line as the weak node. Disconnect the nodes connected to the weak node after the faulty line is disconnected, and extend outwards to the main power source, the second DC power source, the low-voltage side of the upstream substation, or a regional power grid that is 5 or more nodes away from the weak node. Figure 3 As shown; S2. Analyze and calculate the reactive power consumption during system transient faults. After a system fault, select the power grid in the area where the plant is located, which is relatively weak on both sides of the fault, and perform reactive power demand calculation. Consider the reactive power absorption caused by the recovery of the converter commutation failure, the charging power of the disconnected line and the reactive power supply, and the transient reactive power regulation capability that the unit can provide. S3. Select and retain the proposed installation sites and the weakest power plants, simplifying the network structure of other systems, such as... Figure 4 As shown; S4. Convert the transient reactive power demand at the weak point into the transient reactive power demand of the proposed installation site. The corresponding fitted correlation curves and the installation effects at different nodes are shown below. Figure 1 , Figure 5 As shown; S5. Calculate the rated capacity of the equipment at the proposed installation point based on transient reactive power demand.

[0025] The reactive power demand in S2 is calculated as follows: (1) in, This represents the increased reactive power absorption and decreased reactive power compensation within the i-node converter and its corresponding compensation in the event of a fault, as well as the reduction in reactive power compensation at the converter's site. The calculation for the i-node converter is as follows: (2) In the formula For the short-circuit capacity of the AC node on the valve assembly side, This corresponds to the rated compensation capacity for reactive power compensation; in To disconnect the reactive power value of the power flow on the line, To disconnect the line's rated charging power; (3) In the formula, C is the distributed capacitance value of the line; in Let be the unit regulation capacity of node j, and be the difference between the maximum dynamic non-functional capacity and the static non-functional capacity after a fault. (4) In the formula This refers to the generator terminal voltage. The q-axis electromotive force under strong excitation. This represents the reactive power output value before the unit failure. For d-axis coaxial reactance, The maximum unloaded capacity of the unit after a failure can be obtained through parameter analysis calculation or simulation experiment.

[0026] S3 specifically includes retaining only the proposed installation site and the weakest substation. The power grids on both sides are equivalent to Thevenin models, and the mutual impedance model between the sites is equivalent to the mutual impedance model. The per-unit value of the mutual impedance between the two sites is extracted, with 100MVA as the benchmark.

[0027] S4 specifically includes, Transient reactive power demand conversion: (5) in It is a constant, obtained through fitting. (6) The equivalent mutual impedance between the weak substation and the substation to be installed, after Thevenin's equivalent calculation.

[0028] Calculate the rated capacity of the equipment at the proposed installation point in S5. : (7) In the formula, N is the transient overcurrent multiple of the equipment to be installed.

[0029] The following are examples: Based on the fault indicating insufficient transient reactive power support, a regional power grid analysis is conducted on the relatively weak node 2 on both sides. The regional power grid is defined as the nodes connected to node 2 after disconnecting the faulty line 12, extending outwards to the main power source of the grid, the second DC power source, the low-voltage side of the upstream substation, or at least five nodes away from the weak node. Considering that during the fault of lines 1 and 2, the weakest point is at node 2, but the proposed installation point is at node 4, the transient reactive power demand that node 2 needs to compensate for is calculated first, and then its capacity is converted to the value for node 4.

[0030] The reactive power consumption during system transient faults is analyzed and calculated. After a system fault, the power grid in the area where the weaker power plant is located is selected on both sides of the fault, and the reactive power demand is calculated. The calculation takes into account the reactive power absorption caused by the failure of the converter to recover, the charging power of the disconnected line and the reactive power supply, and the transient reactive power regulation capability that the unit can provide.

[0031]

[0032] (1) in, This refers to the increased reactive power absorption of the converters and corresponding compensations at the three nodes under fault conditions, and the decreased reactive power compensation within the site where the converters are located, based on... Figure 5 The fault voltage waveform shows that the voltage at node 3 drops to 0.1 pu and then is expected to recover to 0.8 pu in 1.15 seconds; it recovers to 0.9 pu in 1.5 seconds; and finally recovers to approximately 1.0 pu. Therefore, the voltage change from DC restart to stable voltage is 0.2 pu. (2) (3) in The reactive power values ​​of the power flow on nodes 1-2 of the disconnected line. The rated charging power for disconnecting the line.

[0033] (4) In the formula, C is the distributed capacitance value of the line.

[0034] in The regulating capacity of the unit at node j is determined by considering the unit's operating characteristics before the fault and the difference between the maximum dynamic non-functional capacity and the static non-functional capacity after the fault.

[0035] MVar(5) MVar(6) MVar(7) MVar(8) (9) The proposed installation site and the weakest substation are retained, while the network structure of other systems is simplified. Only the proposed installation site and the weakest substation are retained. The power grids on both sides are equivalent to the Thevenin model, and the mutual impedance model between the sites is equivalent to the mutual impedance model. The per-unit value of the mutual impedance between the two sites is extracted, with 100MVA as the reference, X12=0.0317.

[0036] Convert the transient reactive power demand of the weak point into the transient reactive power demand of the proposed installation site: (10) The dynamic reactive power required for the proposed installation site is calculated using a transient overcurrent multiple of 3 times the rated power of the actual equipment. (11).

[0037] As can be seen from the above, the transient reactive power calculation described in this embodiment of the invention considers the grid division of the fault-prone area, the reactive power increase during the transient period of the LCC converter, the reactive power support of the disconnected line power flow, the power supply of the line charging, and the dynamic reactive power capacity that conventional units can provide, and gives a clear calculation formula. When the transient reactive power demand increases, the reactive power absorption of the converter described in formula (2) increases; it considers the reduction in compensation capacity caused by the in-station compensation and voltage drop, and at the same time determines the voltage value during the period of maximum reactive power absorption demand. When the line charging power loss is calculated, the method simplifies the calculation by considering the rated voltage, without needing to analyze the operating voltage state before the fault, thus simplifying the calculation; it considers the grid division of the fault-prone area, making the method simple. The transient reactive power conversion formula considers the influence of mutual impedance between stations and obtains their corresponding relationship, which is verified by simulation calculation and obtained by fitting the mutual impedance of the station to the transient reactive power installation demand.

[0038] In another aspect, the present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.

[0039] In another aspect, the present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described above.

[0040] It is understood that the systems, devices, and storage media provided in the embodiments of the present invention correspond to the methods provided in the embodiments of the present invention, and the explanations, examples, and beneficial effects of the relevant content can be referred to the corresponding parts of the above methods.

[0041] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0044] The above 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.

Claims

1. A method for calculating the capacity configuration of transient reactive power equipment, characterized in that, Includes the following steps, S1. For lines that are found to be transiently unstable after a fault, select the weak nodes as the links with longer chain structures on both sides of the line. For the weak nodes, disconnect the nodes connected to the faulty line and extend outward to the large power source, the second DC power source, the low-voltage side of the upper-level substation, or the area power grid that is more than or equal to 5 nodes away from the weak nodes. S2. Analyze and calculate the reactive power consumption during system transient faults. After a system fault, select the power grid area of ​​the weaker substation on either side of the fault and calculate the reactive power demand. Consider the increased reactive power absorption due to converter commutation failure recovery, the charging power of disconnected lines, the reactive power supply, and the transient reactive power regulation capability provided by the generating units. S3. Select and retain the proposed installation sites and the weakest power plants to simplify the network structure of other systems; S4. Convert the transient reactive power demand of the weak point into the transient reactive power demand of the proposed installation site; S5. Calculate the rated capacity of the equipment at the proposed installation point based on transient reactive power demand.

2. The method for calculating the capacity configuration of transient reactive power equipment according to claim 1, characterized in that: The reactive power demand in S2 is calculated as follows: (1) in, This represents the increased reactive power absorption and decreased reactive power compensation within the i-node converter and its corresponding compensation in the event of a fault, as well as the reduction in reactive power compensation at the converter's site. The calculation for the i-node converter is as follows: (2) In the formula For the short-circuit capacity of the AC node on the valve assembly side, This corresponds to the rated compensation capacity for reactive power compensation; in To disconnect the reactive power value of the power flow on the line, To disconnect the line's rated charging power; (3) In the formula, C is the distributed capacitance value of the line; in Let be the unit regulation capacity of node j, and be the difference between the maximum dynamic non-functional capacity and the static non-functional capacity after a fault. (4) In the formula This refers to the generator terminal voltage. The q-axis electromotive force under strong excitation. This represents the reactive power output value before the unit failure. For d-axis coaxial reactance, The maximum unloaded capacity of the unit after a failure can be obtained through parameter analysis calculation or simulation experiment.

3. The method for calculating the capacity configuration of transient reactive power equipment according to claim 2, characterized in that: S3 specifically includes retaining only the proposed installation site and the weakest substation. The power grids on both sides are equivalent to Thevenin models, and the mutual impedance model between the sites is equivalent to the mutual impedance model. The per-unit value of the mutual impedance between the two sites is extracted, with 100MVA as the benchmark.

4. The transient reactive power equipment capacity configuration calculation method according to claim 3, characterized in that: S4 specifically includes, Transient reactive power demand: (5) in It is a constant, obtained through fitting. (6) The mutual impedance between the weak substation and the substation to be installed.

5. The transient reactive power equipment capacity configuration calculation method according to claim 4, characterized in that: Calculate the rated capacity of the equipment at the proposed installation point in S5. : (7) In the formula, N is the transient overcurrent multiple of the equipment to be installed.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, the processor performs the steps of the method as described in any one of claims 1 to 5.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the computer program is executed by the processor, it causes the processor to perform the steps of the method as described in any one of claims 1 to 5.

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