Optimal selection method, system and equipment for short-circuit current margin improvement scheme

Abstract

The invention discloses an optimal selection method, system and equipment for a short-circuit current margin improvement scheme, and the method comprises the steps: firstly collecting basic data related to a short-circuit circuit in a medium-voltage line, constructing a distributed photovoltaic bearing capacity estimation model based on the short-circuit current margin, and solving the distributed photovoltaic bearing capacity before the implementation of a short-circuit current margin improvement measure in the line; then, adopting different measures to improve the short-circuit current margin of the power grid, and quantifying the improvement effect of the distributed photovoltaic bearing capacity after the implementation of each short-circuit current margin improvement measure; and finally, evaluating the unit investment improvement effect of each short-circuit current margin improvement measure, and determining the short-circuit current margin improvement measure with the highest unit investment improvement effect. The improvement effect of the bearing capacity is quantitatively analyzed, the actual influence of different improvement measures on the safety of the power grid is estimated in advance, it is ensured that the power grid can safely and stably accept more distributed energy sources, meanwhile, scheme comparison and selection of multiple improvement measures are carried out, investment decision is optimized, and the economic benefit is improved. And the sustainability and long-term benefits of a power grid construction and reconstruction project can be ensured.

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 scheme. Background Art

[0002] With the advancement of the "dual carbon" policy and the deepening of the construction of new distribution networks, a large number of high-penetration distributed photovoltaic power generation systems are connected to the distribution network, and their impact on the stability of the distribution network is becoming increasingly prominent. In a high-penetration environment, the access 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. Especially in high-load intensive areas such as large industrial areas and urban centers, if the short-circuit current exceeds the design capacity of the existing protection device, a short-circuit fault will occur, which will most likely lead to serious power outages and even damage equipment. Therefore, when connecting distributed power sources in areas with limited short-circuit current margins, it is particularly important to take some measures to improve the short-circuit current margin, such as strengthening the power grid structure and optimizing the electrical parameter configuration. However, before implementing measures to improve the short-circuit current margin, how to accurately predict the effect of such measures on the improvement of the carrying capacity of distributed power sources has become a key issue that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to provide a preferred method, system and device for improving a short-circuit current margin solution in view of the above-mentioned problems existing in the prior art.

[0004] To achieve the above objectives, the technical solution of the present invention is 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 the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, the distributed photovoltaic carrying capacity before the implementation of short-circuit current margin improvement measures in the line is solved;

[0008] S3. Use different measures to improve the short-circuit current margin of the line, and compare it with the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures, and 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 technical and economic analysis on the distributed photovoltaic carrying capacity of each measure and its improvement effect, 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 a 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 It 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, including a model building module, a 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 it with the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures, and 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 of each measure and its improvement effect, 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 a 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 It is the investment cost of various short-circuit current margin improvement measures.

[0035] In a third aspect, the present invention provides a preferred device for a short-circuit current margin improvement 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 used to execute the aforementioned preferred method of the short-circuit current margin improvement solution according to the 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 preferred method of the aforementioned short-circuit current margin improvement solution are implemented.

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

[0041] The present invention proposes an optimization 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 it 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 of each measure and its improvement effect, 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 the short-circuit current margin, the number of outgoing lines of the low-voltage busbar of the substation, the short-circuit capacity of the superior power grid and other factors based on the maximum allowable value of short-circuit current specified in the technical guidelines, and realizes the quantitative analysis of the carrying capacity improvement effect before and after the implementation of the short-circuit current margin improvement measures, and estimates in advance the actual impact of different improvement measures on the security of the power grid, 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, 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 The structure diagram of the system of the present invention is shown in FIG.

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

[0045] The present invention is further described in detail below in conjunction with specific implementations and drawings.

[0046] The present invention proposes an optimization method, system and device for a short-circuit current margin improvement scheme, collects basic data related to short-circuit circuits in medium-voltage lines of a power grid, and based on the maximum allowable value of short-circuit current specified in technical guidelines, comprehensively considers factors such as short-circuit current margin, the number of outgoing lines of a low-voltage busbar of a substation, and the short-circuit capacity of a superior power grid, constructs a distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, and obtains 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 performed on the distributed photovoltaic carrying capacity of each measure and its improvement effect, and the short-circuit current margin improvement measure with the highest mid-level investment improvement effect is determined, so as to ensure that the power grid safely and stably accepts 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] Embodiment 1:

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

[0051] The 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 bus in a substation, the maximum allowable value of short-circuit current in the line specified in relevant technical guidelines, the limit value of short-circuit current, generally 16kA or 20kA, the main power supply node of a certain line partition, such as the central node, the short-circuit current of the upper power grid, and the ratio of distributed photovoltaic short-circuit current to 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 during short-circuit calculation, 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 installed capacity of distributed photovoltaic power generation connected to each feeder line at the low-voltage busbar of the substation is the same, consider the scenario where the impact of distributed photovoltaic power generation on short-circuit current is relatively serious. The scenario is that when the fault point caused by a distributed power source outside a line is close to the busbar, the outlet short-circuit current increases, that is, the distributed power source outside the line helps to increase the short-circuit current. The distributed photovoltaic 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 a 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 for a main power supply node of a line partition, such as a hub node, wherein 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 line in the planning area before the implementation of short-circuit current margin improvement measures is estimated, as shown in Table 1:

[0062] Table 1 The carrying capacity of distributed photovoltaic 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 implementation of the short-circuit current margin improvement measures, and 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 the line include: increasing the system impedance of the line, improving the total impedance of the system, reducing the short-circuit current, thereby improving the short-circuit current margin of the line; reducing the propagation range of the short-circuit current in the line, 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 a larger short-circuit current, thereby improving the short-circuit current margin; for example: selecting high-impedance transformers, installing series reactors on certain key lines, operating the busbar in sections, optimizing the grid structure, using current-limiting fuses or current-limiting circuit breakers, and using circuit breakers with larger interrupting capacity;

[0066] In view of the fact that there are many 10kV low-voltage busbar outgoing lines in the planned area substation, such as 10 circuits, and the photovoltaic installation capacity of a single circuit line 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, which causes the distributed photovoltaics to be limited by the short-circuit current margin and cannot be connected. Two short-circuit current margin improvement measures are planned to be adopted. Among them, measure 1 is to use a larger capacity circuit breaker, which requires an investment of 50,000 yuan, and measure 2 is to add new connections and optimize the existing grid structure, which requires an investment of 100,000 yuan. The short-circuit current margins increased by the two improvement measures are 1kA and 2kA respectively;

[0067] The distributed photovoltaic carrying capacity estimation model based on short-circuit current margin is used to estimate the carrying capacity of distributed photovoltaic after the implementation of two short-circuit current margin improvement measures in the line.

[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 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;

[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 problem of limited short-circuit current margin in the 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 medium-voltage busbar of the substation.

[0075] Embodiment 2:

[0076] like Figure 2 As shown, a preferred system for improving a 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 it with the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures, and 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 of each measure and its improvement effect, 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 a 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 It is the investment cost of various short-circuit current margin improvement measures.

[0091] Embodiment 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 a preferred method of improving the short-circuit current margin solution described in Example 1 according to the instructions in the computer program code.

[0095] Embodiment 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 a preferred method for improving a short-circuit current margin described in this solution are implemented.

Claims

1. A method for optimizing a short-circuit current margin improvement scheme, 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 the distributed photovoltaic carrying capacity estimation model based on short-circuit current margin, the distributed photovoltaic carrying capacity before the implementation of short-circuit current margin improvement measures in the line is solved; S3. Use different measures to improve the short-circuit current margin of the line, and compare it with the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures, and 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 technical and economic analysis on the distributed photovoltaic carrying capacity of each measure and its improvement effect, 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 a 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 It is the investment cost of various short-circuit current margin improvement measures.

5. A system for optimizing the short-circuit current margin improvement scheme, characterized in that: The system includes a model building module, a bearing capacity solving module, a lifting effect quantification module, and a lifting 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 it with the distributed photovoltaic carrying capacity before the implementation of the short-circuit current margin improvement measures, and 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 of each measure and its improvement effect, 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 optimization system for improving the short-circuit current margin 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 a 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 optimal system for improving the short-circuit current margin 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 optimal system for improving the short-circuit current margin 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 It is the investment cost of various short-circuit current margin improvement measures.

9. An optimal 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 a preferred method of a short-circuit current margin improvement solution as described in any one of claims 1-4 according to 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 a short-circuit current margin improvement solution described in any one of claims 1 to 4 are implemented.

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