A method, system and device for optimizing short-circuit current margin improvement scheme

Abstract

A method, system and device for optimizing a short-circuit current margin improvement scheme. The method first collects basic data related to short-circuit circuits in medium-voltage lines, constructs a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, and solves the distributed photovoltaic carrying capacity before the implementation of short-circuit current margin improvement measures in the lines; then adopts different measures to improve the short-circuit current margin of the power grid, and quantifies the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure; finally, evaluates the unit investment improvement effect of each short-circuit current margin improvement measure, and determines the short-circuit current margin improvement measure with the highest unit investment improvement effect. The present invention quantitatively analyzes the improvement effect of carrying capacity, realizes the advance estimation of the actual impact of different improvement measures on the safety of the power grid, ensures that the power grid can safely and stably accept more distributed energy, and at the same time, carries out scheme comparison of multiple improvement measures, optimizes investment decisions, and helps to ensure the sustainability and long-term benefits of power grid construction and transformation projects.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution network planning, and in particular relates to an optimization method, system and equipment for a short-circuit current margin improvement solution. Background Art

[0002] With the deepening construction of new distribution networks, a large number of high-penetration distributed photovoltaic power generation systems are being connected to the distribution network, and their impact on distribution network stability is becoming increasingly prominent. In a high-penetration environment, the integration of a large number of distributed photovoltaic power sources may cause a series of problems in the local distribution network, such as voltage fluctuations, frequency deviations, and increased short-circuit currents. This is especially true in high-load dense areas such as large industrial areas and urban centers. If the short-circuit current exceeds the design capacity of existing protection devices, a short-circuit fault will occur, which is very likely to cause serious power outages and even damage equipment. Therefore, when connecting distributed power sources in areas with limited short-circuit current margin, it is particularly important to take measures to improve the short-circuit current margin, such as strengthening the power grid structure and optimizing electrical parameter configuration. However, before implementing short-circuit current margin improvement measures, how to accurately predict the effect of such measures on the carrying capacity of distributed power sources has become a key issue that needs to be addressed. Summary of the Invention

[0003] The object of the present invention is to provide an optimal method, system and device for improving the short-circuit current margin in response to the above-mentioned problems in the prior art.

[0004] To achieve the above objectives, the technical solutions of the present invention are as follows:

[0005] In a first aspect, the present invention proposes a preferred method for improving a short-circuit current margin solution, comprising:

[0006] S1. Collect basic data related to short-circuit circuits in medium-voltage lines and build a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin;

[0007] S2. Using a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, calculate the distributed photovoltaic carrying capacity before implementing short-circuit current margin improvement measures in the line;

[0008] S3. Utilize different measures to improve the short-circuit current margin of the line and compare the results with the distributed photovoltaic carrying capacity before the short-circuit current margin improvement measures are implemented. Quantify the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line. The improvement measures include increasing the system impedance of the line, reducing the propagation range of the short-circuit current in the line, and improving the short-circuit current handling capacity of the line.

[0009] S4. Conduct a technical and economic analysis of the distributed photovoltaic carrying capacity and its improvement effect of each measure, evaluate the unit investment improvement effect of each short-circuit current margin improvement measure, and select the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line.

[0010] In S1, the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is:

[0011]

[0012] I dl =I Dmax -I sd ;

[0013] In the above formula, S dg is the distributed photovoltaic carrying capacity of the line, U N is the rated voltage, I dl is the short-circuit current margin in the line, γ d is the ratio of the distributed photovoltaic short-circuit current to the rated current in the line, N bf is the number of outgoing lines of a low-voltage busbar in the substation, I Dmax The maximum permissible value of short-circuit current in the line specified in the relevant technical guidelines, I sd The short-circuit current of the upstream power grid of the main power supply node of the line partition.

[0014] In S3, the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line is calculated using the following formula:

[0015] ΔS dg =S dg1 -S dg0 ;

[0016] In the above formula, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, S dg1 is the distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures, S dg0 This is the distributed photovoltaic carrying capacity before the implementation of various short-circuit current margin improvement measures.

[0017] In S4, the unit investment improvement effect of each short-circuit current margin improvement measure is calculated using the following formula:

[0018] ΔE dl =ΔS dg / P dl ;

[0019] In the above formula, ΔE dl is the unit investment improvement effect of each short-circuit current margin improvement measure in the line, ΔSdg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, P dl is the investment cost of various short-circuit current margin improvement measures.

[0020] In a second aspect, the present invention proposes an optimal system for improving a short-circuit current margin solution, comprising a model building module, a load-bearing capacity solving module, an improvement effect quantification module, and an improvement effect evaluation module;

[0021] The model building module is used to collect basic data related to short-circuit circuits in medium-voltage lines and build a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin;

[0022] The carrying capacity solving module is used to solve the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures in the line by using the distributed photovoltaic carrying capacity estimation model based on the short-circuit current margin;

[0023] The improvement effect quantification module is used to improve the short-circuit current margin of the line by adopting different measures, and compare the distributed photovoltaic carrying capacity before the short-circuit current margin improvement measures are implemented to quantify the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line. The improvement measures include increasing the system impedance of the line, reducing the propagation range of the short-circuit current in the line, and improving the short-circuit current handling capacity of the line;

[0024] The improvement effect evaluation module is used to perform technical and economic analysis on the distributed photovoltaic carrying capacity and improvement effect of each measure, evaluate the unit investment improvement effect of each short-circuit current margin improvement measure, and select the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line.

[0025] In the model building module, the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is:

[0026]

[0027] I dl =I Dmax -I sd ;

[0028] In the above formula, S dg is the distributed photovoltaic carrying capacity of the line, U N is the rated voltage, I dl is the short-circuit current margin in the line, γ d is the ratio of the distributed photovoltaic short-circuit current to the rated current in the line, N bf is the number of outgoing lines of a low-voltage busbar in the substation, I Dmax The maximum permissible value of short-circuit current in the line specified in the relevant technical guidelines, Isd The short-circuit current of the upstream power grid of the main power supply node of the line partition.

[0029] In the improvement effect quantification module, the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line is calculated using the following formula:

[0030] ΔS dg =S dg1 -S dg0 ;

[0031] In the above formula, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, S dg1 is the distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures, S dg0 This is the distributed photovoltaic carrying capacity before the implementation of various short-circuit current margin improvement measures.

[0032] In the improvement effect evaluation module, the unit investment improvement effect of each short-circuit current margin improvement measure is calculated using the following formula:

[0033] ΔE dl =ΔS dg / P dl ;

[0034] In the above formula, ΔE dl is the unit investment improvement effect of each short-circuit current margin improvement measure in the line, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, P dl is the investment cost of various short-circuit current margin improvement measures.

[0035] In a third aspect, the present invention provides an optimal device for improving a short-circuit current margin solution, comprising a processor and a memory;

[0036] The memory is used to store computer program code and transmit the computer program code to the processor;

[0037] The processor is configured to execute the aforementioned preferred method for improving the short-circuit current margin according to instructions in the computer program code.

[0038] In a fourth aspect, the present invention provides a computer storage medium having a computer program stored thereon;

[0039] When the computer program is executed by a processor, the steps of the aforementioned preferred method for improving the short-circuit current margin are implemented.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention proposes an optimal method, system and equipment for a short-circuit current margin improvement scheme. The method first collects basic data related to short-circuit circuits in medium-voltage lines and constructs a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin; uses the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin to solve the distributed photovoltaic carrying capacity before the implementation of short-circuit current margin improvement measures in the line; then adopts different measures to improve the short-circuit current margin of the line, and compares them with the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures, and quantifies the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line; finally, a technical and economic analysis is performed on the distributed photovoltaic carrying capacity and its improvement effect of each measure, the unit investment improvement effect of each short-circuit current margin improvement measure is evaluated, and the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line is selected. On the one hand, when establishing a distributed carrying capacity estimation model based on short-circuit current margin, this method takes into account factors such as short-circuit current margin, the number of outgoing lines of the substation low-voltage busbar, and the short-circuit capacity of the superior power grid based on the maximum allowable value of short-circuit current specified in the technical guidelines. It realizes the quantitative analysis of the carrying capacity improvement effect before and after the implementation of short-circuit current margin improvement measures, and estimates in advance the actual impact of different improvement measures on power grid security, ensuring that the power grid can safely and stably accept more distributed energy; on the other hand, this method conducts a comparison of various improvement measures, optimizes investment decisions, and helps to ensure the sustainability and long-term benefits of power grid construction and transformation projects. It has strong practicality and operability, and can be widely used in the planning and design of distribution networks and other fields, providing strong technical support for the large-scale access of distributed photovoltaics and the safe and stable operation of power grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The figure is an overall flow chart of the method of the present invention.

[0043] Figure 2 1 is a structural diagram of the system of the present invention.

[0044] Figure 3 This is a structural diagram of the equipment described in Example 3. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0046] The present invention proposes an optimization method, system and equipment for a short-circuit current margin improvement scheme, which collects basic data related to short-circuit circuits in medium-voltage lines of a power grid. Based on the maximum allowable value of short-circuit current specified in technical guidelines, the system comprehensively considers factors such as short-circuit current margin, the number of outgoing lines of the substation low-voltage busbar, and the short-circuit capacity of the upper-level power grid, and constructs a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin to obtain the distributed photovoltaic carrying capacity before the implementation of short-circuit current margin improvement measures. Then, different measures are adopted to improve the short-circuit current margin of the power grid, and a technical and economic analysis is conducted on the distributed photovoltaic carrying capacity of each measure and its improvement effect, to determine the short-circuit current margin improvement measure with the highest median investment improvement effect, thereby ensuring that the power grid can safely and stably accept more distributed energy while optimizing investment decisions, which helps to ensure the sustainability and long-term benefits of power grid construction and transformation projects.

[0047] Example 1:

[0048] Taking a certain planning area as the research object, the effect of increasing the distributed photovoltaic carrying capacity after the short-circuit current margin of a medium-voltage line in the substation in the area is evaluated. The settings of the relevant parameters include the number of outgoing low-voltage busbars of the substation in the planning area being 4, 6, 8, 10, 12, and 14 respectively, the short-circuit current margin of the medium-voltage line being 1kA, 2kA, 3kA, 4kA, and 5kA respectively, and the rated voltage of the photovoltaic power source being 10kV.

[0049] like Figure 1 As shown, a preferred method for improving the short-circuit current margin solution is performed in the following steps:

[0050] 1. Collect basic data related to short-circuit circuits in medium-voltage lines and build a distributed photovoltaic load capacity estimation model based on short-circuit current margin;

[0051] Basic data related to short-circuit circuits in medium-voltage lines include: the short-circuit current margin of distributed photovoltaic access points; the number of outgoing lines of a low-voltage busbar in the substation; the maximum allowable short-circuit current in the line as specified in relevant technical guidelines; the short-circuit current limit, which is generally 16kA or 20kA; the short-circuit current of the upstream power grid at the main power supply node of a certain line section, such as the central node; and the ratio of the distributed photovoltaic short-circuit current to the rated current, which usually does not exceed 1.5.

[0052] When a distributed photovoltaic power source is connected to the grid, the DC power is converted into AC power through an inverter. This type of power source can be considered as a constant current source in short-circuit calculations, and its corresponding short-circuit current value can be expressed as:

[0053]

[0054] In the above formula, I dis the short-circuit current value of the distributed photovoltaic power source in the line, I dl is the short-circuit current margin in the line, γ d is the ratio of the distributed photovoltaic short-circuit current to the rated current in the line, I vn is the rated current of distributed photovoltaic, S dg is the distributed photovoltaic carrying capacity of the line, U N is the rated voltage;

[0055] Assuming that the distributed PV installed capacity connected to each feeder line at the substation low-voltage busbar is the same, consider a scenario where the distributed PV has a relatively severe impact on short-circuit current. This scenario involves a fault point caused by a distributed power source outside the line close to the busbar, increasing the outlet short-circuit current. In other words, the distributed power source outside the line contributes to the increase in short-circuit current. The distributed PV capacity needs to meet the following requirements:

[0056] (N bf -1)I d ≤I dl ;

[0057] I dl =I Dmax -I sd ;

[0058] In the above formula, N bf is the number of outgoing lines of a low-voltage busbar in the substation, I Dmax The maximum permissible value of short-circuit current in the line specified in the relevant technical guidelines, I sd The short-circuit current of the upstream power grid at a main power source node of a line partition, such as a hub node, where the upstream power grid is represented by a model of a voltage source in series with a reactance;

[0059] In summary, the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is constructed as follows:

[0060]

[0061] 2. Using the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, the carrying capacity of distributed photovoltaics under different short-circuit current margins in the planning area before the implementation of short-circuit current margin improvement measures is estimated, as shown in Table 1:

[0062] Table 1. Carrying capacity of distributed photovoltaics under different short-circuit current margins. Unit: MW

[0063]

[0064] 3. Use different measures to improve the short-circuit current margin of the line and compare it with the distributed photovoltaic carrying capacity before the short-circuit current margin improvement measures are implemented. Quantify the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line;

[0065] Measures to improve the short-circuit current margin of a line include: increasing the system impedance of the line, improving the total impedance of the system, reducing the short-circuit current, and thus improving the short-circuit current margin of the line; reducing the propagation range of the short-circuit current in the line and optimizing the distribution of the short-circuit current, thereby improving the short-circuit current margin of the line; improving the short-circuit current handling capacity of the line so that the system can handle larger short-circuit currents, thereby improving the short-circuit current margin; for example: selecting high-impedance transformers, installing series reactors on certain key lines, operating busbars in sections, optimizing the grid structure, using current-limiting fuses or current-limiting circuit breakers, and adopting circuit breakers with larger interrupting capacities;

[0066] In view of the fact that there are many 10kV low-voltage busbar outgoing lines in the planned regional substation, such as 10 circuits, and the photovoltaic installed capacity of a single circuit is large, such as 6MW, and the short-circuit current margin of the power grid is only 4kA, but the short-circuit current generated by distributed photovoltaics is greater than 4.68kA, resulting in the distributed photovoltaics being limited by the short-circuit current margin and unable to be connected. Two short-circuit current margin improvement measures are planned. Among them, measure 1 is to use a larger capacity circuit breaker, which requires an investment of 50,000 yuan. Measure 2 is to add a new connection and optimize the existing grid structure, which requires an investment of 100,000 yuan. The two improvement measures increase the short-circuit current margin by 1kA and 2kA respectively.

[0067] Using the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, the carrying capacity of distributed photovoltaics after the implementation of two short-circuit current margin improvement measures in the line is estimated;

[0068] The improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line is calculated using the following formula:

[0069] ΔS dg =S dg1 -S dg0 ;

[0070] In the above formula, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, S dg1 is the distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures, S dg0 This is the distributed photovoltaic carrying capacity before the implementation of each short-circuit current margin improvement measure; among them, the distributed photovoltaic carrying capacity of measure 1 increased by 1.28MW, and the distributed photovoltaic carrying capacity of measure 2 increased by 2.57MW.

[0071] 4. Use the incremental evaluation method to conduct a technical and economic analysis of the distributed photovoltaic carrying capacity and its improvement effect of each measure, evaluate the unit investment improvement effect of each short-circuit current margin improvement measure, and select the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line;

[0072] The unit investment improvement effect of each short-circuit current margin improvement measure is calculated using the following formula:

[0073] ΔE dl =ΔS dg / P dl ;

[0074] In the above formula, ΔE dl is the unit investment improvement effect of each short-circuit current margin improvement measure in the line, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, P dl is the investment cost of each short-circuit current margin improvement measure; among them, the unit improvement effect of measure 1 is 0.316MW / 10,000 yuan, and the unit improvement effect of measure 2 is 0.257MW / 10,000 yuan. Therefore, in view of the limited short-circuit current margin problem in this planning area, it is recommended to adopt measure 1, that is, to use a larger capacity circuit breaker to improve the short-circuit current margin of the substation medium-voltage busbar.

[0075] Example 2:

[0076] like Figure 2 As shown, a preferred system for improving the short-circuit current margin solution includes a model building module, a load-bearing capacity solving module, an improvement effect quantification module, and an improvement effect evaluation module;

[0077] The model building module is used to collect basic data related to short-circuit circuits in medium-voltage lines and build a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin;

[0078] The carrying capacity solving module is used to solve the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures in the line by using the distributed photovoltaic carrying capacity estimation model based on the short-circuit current margin;

[0079] The improvement effect quantification module is used to improve the short-circuit current margin of the line by adopting different measures, and compare the distributed photovoltaic carrying capacity before the short-circuit current margin improvement measures are implemented to quantify the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line. The improvement measures include increasing the system impedance of the line, reducing the propagation range of the short-circuit current in the line, and improving the short-circuit current handling capacity of the line;

[0080] The improvement effect evaluation module is used to perform technical and economic analysis on the distributed photovoltaic carrying capacity and improvement effect of each measure, evaluate the unit investment improvement effect of each short-circuit current margin improvement measure, and select the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line.

[0081] In the model building module, the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is:

[0082]

[0083] I dl =I Dmax -I sd ;

[0084] In the above formula, S dg is the distributed photovoltaic carrying capacity of the line, U N is the rated voltage, I dl is the short-circuit current margin in the line, γ d is the ratio of the distributed photovoltaic short-circuit current to the rated current in the line, N bf is the number of outgoing lines of a low-voltage busbar in the substation, I Dmax The maximum permissible value of short-circuit current in the line specified in the relevant technical guidelines, I sd The short-circuit current of the upstream power grid of the main power supply node of the line partition.

[0085] In the improvement effect quantification module, the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line is calculated using the following formula:

[0086] ΔS dg =S dg1 -S dg0 ;

[0087] In the above formula, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, S dg1 is the distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures, S dg0 This is the distributed photovoltaic carrying capacity before the implementation of various short-circuit current margin improvement measures.

[0088] In the improvement effect evaluation module, the unit investment improvement effect of each short-circuit current margin improvement measure is calculated using the following formula:

[0089] ΔE dl =ΔS dg / P dl ;

[0090] In the above formula, ΔE dlis the unit investment improvement effect of each short-circuit current margin improvement measure in the line, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, P dl is the investment cost of various short-circuit current margin improvement measures.

[0091] Example 3:

[0092] like Figure 3 As shown, a preferred device for a short-circuit current margin improvement solution includes a processor and a memory;

[0093] The memory is used to store computer program code and transmit the computer program code to the processor;

[0094] The processor is used to execute the preferred method of the short-circuit current margin improvement solution described in Example 1 according to the instructions in the computer program code.

[0095] Example 4:

[0096] A computer storage medium having a computer program stored thereon;

[0097] When the computer program is executed by a processor, the steps of the preferred method of the short-circuit current margin improvement solution described in this solution are implemented.

Claims

1. A method for optimizing a short-circuit current margin improvement solution, characterized in that: The method comprises: S1. Collect basic data related to short-circuit circuits in medium-voltage lines and build a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin; S2. Using a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, calculate the distributed photovoltaic carrying capacity before implementing short-circuit current margin improvement measures in the line; S3. Utilize different measures to improve the short-circuit current margin of the line and compare the results with the distributed photovoltaic carrying capacity before the short-circuit current margin improvement measures are implemented. Quantify the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line. The improvement measures include increasing the system impedance of the line, reducing the propagation range of the short-circuit current in the line, and improving the short-circuit current handling capacity of the line. S4. Conduct a technical and economic analysis of the distributed photovoltaic carrying capacity and its improvement effect of each measure, evaluate the unit investment improvement effect of each short-circuit current margin improvement measure, and select the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line.

2. The method for optimizing the short-circuit current margin improvement scheme according to claim 1, characterized in that: In S1, the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is: I dl =I Dmax -I sd ; In the above formula, S dg is the distributed photovoltaic carrying capacity of the line, U N is the rated voltage, I dl is the short-circuit current margin in the line, γ d is the ratio of the distributed photovoltaic short-circuit current to the rated current in the line, N bf is the number of outgoing lines of a low-voltage busbar in the substation, I Dmax The maximum permissible value of short-circuit current in the line specified in the relevant technical guidelines, I sd The short-circuit current of the upstream power grid of the main power supply node of the line partition.

3. The method for optimizing the short-circuit current margin improvement scheme according to claim 1, characterized in that: In S3, the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line is calculated using the following formula: ΔS dg =S dg1 -S dg0 ; In the above formula, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, S dg1 is the distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures, S dg0 This is the distributed photovoltaic carrying capacity before the implementation of various short-circuit current margin improvement measures.

4. The method for optimizing the short-circuit current margin improvement scheme according to claim 1, characterized in that: In S4, the unit investment improvement effect of each short-circuit current margin improvement measure is calculated using the following formula: ΔE dl =ΔS dg / P dl ; In the above formula, ΔE dl is the unit investment improvement effect of each short-circuit current margin improvement measure in the line, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, P dl is the investment cost of various short-circuit current margin improvement measures.

5. A system for optimizing the short-circuit current margin improvement solution, characterized in that: The system includes a model building module, a bearing capacity solving module, an improvement effect quantification module, and an improvement effect evaluation module; The model building module is used to collect basic data related to short-circuit circuits in medium-voltage lines and build a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin; The carrying capacity solving module is used to solve the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures in the line by using the distributed photovoltaic carrying capacity estimation model based on the short-circuit current margin; The improvement effect quantification module is used to improve the short-circuit current margin of the line by adopting different measures, and compare the distributed photovoltaic carrying capacity before the short-circuit current margin improvement measures are implemented to quantify the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line. The improvement measures include increasing the system impedance of the line, reducing the propagation range of the short-circuit current in the line, and improving the short-circuit current handling capacity of the line; The improvement effect evaluation module is used to perform technical and economic analysis on the distributed photovoltaic carrying capacity and improvement effect of each measure, evaluate the unit investment improvement effect of each short-circuit current margin improvement measure, and select the short-circuit current margin improvement measure with the highest unit investment improvement effect in the line.

6. The system for optimizing the short-circuit current margin improvement solution according to claim 5, characterized in that: In the model building module, the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is: I dl =I Dmax -I sd ; In the above formula, S dg is the distributed photovoltaic carrying capacity of the line, U N is the rated voltage, I dl is the short-circuit current margin in the line, γ d is the ratio of the distributed photovoltaic short-circuit current to the rated current in the line, N bf is the number of outgoing lines of a low-voltage busbar in the substation, I Dmax The maximum permissible value of short-circuit current in the line specified in the relevant technical guidelines, I sd The short-circuit current of the upstream power grid of the main power supply node of the line partition.

7. The system for optimizing the short-circuit current margin improvement solution according to claim 5, characterized in that: In the improvement effect quantification module, the improvement effect of the distributed photovoltaic carrying capacity after the implementation of each short-circuit current margin improvement measure in the line is calculated using the following formula: ΔS dg =S dg1 -S dg0 ; In the above formula, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, S dg1 is the distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures, S dg0 This is the distributed photovoltaic carrying capacity before the implementation of various short-circuit current margin improvement measures.

8. The system for optimizing the short-circuit current margin improvement solution according to claim 5, characterized in that: In the improvement effect evaluation module, the unit investment improvement effect of each short-circuit current margin improvement measure is calculated using the following formula: ΔE dl =ΔS dg / P dl ; In the above formula, ΔE dl is the unit investment improvement effect of each short-circuit current margin improvement measure in the line, ΔS dg is the improvement effect of distributed photovoltaic carrying capacity after the implementation of various short-circuit current margin improvement measures in the line, P dl is the investment cost of various short-circuit current margin improvement measures.

9. A preferred device for improving the short-circuit current margin solution, characterized in that: including a processor and a memory; The memory is used to store computer program code and transmit the computer program code to the processor; The processor is used to execute the preferred method of the short-circuit current margin improvement solution according to any one of claims 1 to 4 according to the instructions in the computer program code.

10. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the preferred method of the short-circuit current margin improvement solution according to any one of claims 1 to 4 are implemented.

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