Power transmission section transformation method and system considering power transmission capability

Abstract

The invention discloses a power transmission section transformation method and system considering power transmission capability, and the method comprises the steps: obtaining a plurality of typical working conditions based on the annual operation data of a target power transmission section, obtaining the load rate extreme values and average load rates of all lines of the target power transmission section under different typical working conditions, and the power flow entropy of the target power transmission section, a power transmission section power transmission capability evaluation index system is constructed; and under the power transmission section power transmission capability evaluation index system, evaluating the power transmission capability of the target power transmission section under different typical working conditions, and transforming the target power transmission section according to an evaluation result. Through the design of the power transmission section power transmission capability evaluation system based on the annual operation data, the problems of unbalanced load and insufficient transmission capability of the power transmission section in the prior art are solved, and the beneficial effects of improving the power transmission capability, improving the power grid balance and enhancing the system stability are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible AC power flow regulating device configuration, and in particular relates to a method and system for power transmission section transformation considering power transmission capacity. Background Art

[0002] In the new power system, due to the natural distribution of power flow, the power grid cannot operate economically optimally, the capacity of power transmission and transformation equipment is tight and overloaded, and it is impossible to coordinate comprehensively. The controllability of the power flow of the key transmission section supplying power to the regional power grid is poor. It is easy to have improper power distribution and direction, which will cause the following problems: some lines and equipment are overloaded, some lines and equipment are underloaded, and it is easy to cause stability problems; the active power loss of the system increases, the economy of the system operation is poor, and it is easy to form "power bypass" or "power backflow"; the improper power distribution of the system leads to voltage quality that does not meet the requirements. Therefore, how to balance the transmission power of each line in the transmission section and reduce the overload rate of the transmission line is a necessary condition to ensure the safe and stable operation of each transmission line and key node in the power grid. At present, the method of power transmission section transformation considering power transmission capacity generally adopts the method of increasing the capacity of AC lines. When the transmission capacity of the AC transmission section is limited, it can be transformed by increasing the voltage level, adding parallel lines, using high-temperature superconducting wires, transforming substations, optimizing the dispatching system, and other methods. The above transformation method can not only improve the power transmission capacity, but also enhance the reliability and stability of the power grid to a certain extent. However, in actual power grids, the problem of limited section transmission capacity is mostly caused by the uneven distribution of power flow in the transmission lines. Moreover, the transmission lines with limited transmission are concentrated in the urban load center, and the land resources are very tight. It is difficult to implement the method of transforming the transmission capacity by adding new equipment. Therefore, the power flow regulating device can be used to tap the transmission potential of the transmission section, avoiding the waste of construction costs and increasing the area of ​​the transmission channel.

[0003] The use of advanced electrical equipment for power flow regulation is an important part of the construction of future new power systems. The technical means for active power flow regulation can be divided into flexible AC equipment regulation technology and "AC to DC" flexible DC power flow regulation device regulation technology. The above technologies have been applied in actual projects and have good promotion prospects. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention proposes a method and system for transforming a power transmission section taking into account the power transmission capacity.

[0005] The technical solution of the present invention is as follows:

[0006] A method for transforming a power transmission section considering power transmission capacity, comprising:

[0007] Based on the annual operation data of the target transmission section, several typical operating conditions are obtained;

[0008] Obtain the load rate extreme value and average load rate of all lines in the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a transmission section power transmission capacity evaluation index system that comprehensively considers the transmission section line operation capacity and the balance degree of the transmission section;

[0009] Under the transmission section power transmission capacity evaluation index system, the power transmission capacity of the target transmission section under different typical working conditions is evaluated, and based on the evaluation results, the target transmission section is modified by adding new lines, configuring flexible AC power flow regulation devices, or converting to DC.

[0010] Furthermore, the calculation method of the load rate extreme value of the target transmission section line under different typical working conditions is as follows:

[0011]

[0012]

[0013] In the formula, μ min,i represents the minimum load rate in the target transmission section under the ith typical operating condition; μ max,i represents the maximum load rate in the target transmission section under the ith typical operating condition; μ t,i represents the load rate of the tth line in the target transmission section under the ith typical operating condition; N is the total number of all transmission lines in the target transmission section; P t,i is the transmission power of the tth line in the target transmission section under the ith typical working condition; P tN is the rated transmission power of the tth line in the target transmission section; M is the total number of typical operating conditions.

[0014] Furthermore, the calculation method of the average load rate under different typical working conditions is as follows:

[0015]

[0016] In the formula, μ aver,i It represents the average load rate of all lines in the target transmission section under the i-th typical operating condition.

[0017] Furthermore, the calculation method of the power flow entropy of the target transmission section under different typical working conditions is as follows:

[0018]

[0019] Where H i is the power flow entropy of the target transmission section under the i-th typical operating condition; P(k) iis the probability that the line load rate is at (kc, (k+1)c) under the ith typical operating condition; α is a constant coefficient; ln is the logarithmic sign of a natural number; L is the number of load rate interval divisions.

[0020] Furthermore, the probability P(k) that the line load rate is at (kc, (k+1)c) under the i-th typical operating condition is i The method to obtain is as follows:

[0021] A constant sequence is constructed to describe the probability level of the target line load, where the constant sequence C is defined as:

[0022] C=[0,c,2c,...,...,kc,...,...,Lc], Lc=100%

[0023] The constant sequence C divides the line load rate into L+1 intervals; c is the set load rate interval range; under the i-th working condition, the probability P(k) that the load rate is in (kc, (k+1)c) is i It can be expressed as:

[0024]

[0025] Where Ik,i is the load rate μ under the i-th working condition t,i ∈(kc,(k+1)c).

[0026] Furthermore, the transmission section transmission capacity evaluation index matrix PF of the transmission section power transmission capacity evaluation index system is expressed as:

[0027]

[0028] In the formula, μ min,1 , μ min,2 and μ min,M are the minimum load rates in the target transmission section under the first, second and Mth typical working conditions respectively; μ max,1 , μ max,2 and μ max,M are the maximum load rates in the target transmission section under the first, second and Mth typical operating conditions respectively; μ aver,1 , μ aver,2 and μ aver,M are the average load rates of all lines in the target transmission section under the 1st, 2nd and Mth typical operating conditions respectively; M is the total number of typical operating conditions.

[0029] Furthermore, the specific steps of evaluating the power transmission capacity of the target transmission section under different typical working conditions under the power transmission capacity evaluation index system of the transmission section, and performing the transformation of the target transmission section related to the newly added line, the transformation of the configuration of the flexible AC power flow regulation device, or the transformation of the DC conversion according to the evaluation results include:

[0030] Obtain the maximum load rate μ of the target transmission section under all typical working conditions in the transmission capacity evaluation index matrix PF of the transmission section max,PF , the target transmission section power flow entropy H under the typical working condition corresponding to the maximum load rate PF , the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions μ aver,PF And the maximum value μ of the minimum load factor of the target transmission section under all typical working conditions min,PF ;

[0031] If the maximum load rate μ of the target transmission section under all typical working conditions max,PF The target transmission section power flow entropy H under typical working conditions corresponding to the maximum load rate PF If the following constraints are met, the target transmission section does not need to be modified;

[0032] μ max.PF =max{PF(2,:)}<0.8

[0033] H PF <0.5

[0034] Where PF(2,:) is the row vector of the second row of the generated transmission section transmission capacity evaluation index matrix;

[0035] If the maximum value of the minimum load rate of the target transmission section under all typical working conditions is μ min,PF If the following constraints are met, the power transmission capacity of the target transmission section will be improved by adding new lines for transformation;

[0036] μ min.PF =max{PF(1,:)}>0.8

[0037] Where PF(1,:) is the row vector of the first row of the generated transmission section transmission capacity evaluation index matrix;

[0038] If the maximum load rate μ of the target transmission section under all typical operating conditions max,PF , the target transmission section power flow entropy H under the typical working condition corresponding to the maximum load rate PF , the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions μ aver,PFIf the following constraints are met, the load level between lines is balanced by using a flexible AC power flow regulator on the line with the highest load rate;

[0039] μ max.PF =max{PF(2,:)}≥0.8

[0040] H PF ≥0.5

[0041] μ aver.PF ≤0.8

[0042] If the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions, μ aver,PF And the maximum value μ of the minimum load factor of the target transmission section under all typical working conditions min,PF Satisfy the following constraints and select the line corresponding to the minimum load rate in the target section under the typical working condition for DC transformation; μ aver.PF =max{PF(3,:)}>0.8

[0043] μ min.PF ≤0.8.

[0044] A power transmission section transformation system considering power transmission capacity, including a typical operating condition acquisition module, a system construction module and an evaluation and transformation module;

[0045] The typical operating condition acquisition module is used to acquire several typical operating conditions based on the annual operation data of the target transmission section;

[0046] The system construction module is used to obtain the load rate extreme value and average load rate of all lines of the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a transmission section power transmission capacity evaluation index system that comprehensively considers the transmission section line operation capacity and the balance degree of the transmission section;

[0047] The evaluation and transformation module is used to evaluate the power transmission capacity of the target transmission section under different typical working conditions under the power transmission capacity evaluation index system of the transmission section, and to carry out the transformation of the target transmission section related to the addition of new lines, the configuration of flexible AC power flow regulation devices or the transformation to DC according to the evaluation results.

[0048] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor is used to call and run the computer program stored in the memory to execute any of the methods described above.

[0049] A computer-readable storage medium stores a computer program, wherein the computer program implements the steps of any of the above methods when executed by a processor.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention proposes a method and system for power transmission section transformation considering power transmission capacity. The method obtains several typical working conditions based on the annual operation data of the target transmission section, and then obtains the load rate extreme value and average load rate of all lines of the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a power transmission capacity evaluation index system of the transmission section that comprehensively considers the operation capacity of the transmission section line and the balance degree of the transmission section; under the power transmission capacity evaluation index system of the transmission section, the power transmission capacity of the target transmission section under different typical working conditions is evaluated, and according to the evaluation results, the transformation of the target transmission section related to the newly added line, the transformation of the configuration of the flexible AC power flow regulation device or the DC transformation is carried out. The present invention solves the problems of unbalanced load and insufficient transmission capacity of the transmission section in the prior art through the design of the power transmission capacity evaluation system of the transmission section based on annual operation data, scientifically judges the configuration requirements of the transmission section, and clarifies the configuration type and configuration address of the flexible AC and DC regulation device, thereby achieving the beneficial effects of improving the transmission capacity, improving the balance of the power grid and enhancing the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a method for transforming a power transmission section taking into account power transmission capacity in an embodiment;

[0053] Figure 2 A schematic diagram of the topological structure of the power transmission section in the embodiment;

[0054] Figure 3 It is a tidal distribution diagram of the summer working condition when the application embodiment part in the embodiment is not modified;

[0055] Figure 4 This is the tidal distribution diagram of the Xiada working condition after the application embodiment part has been transformed in the embodiment. DETAILED DESCRIPTION

[0056] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications of the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0057] Embodiment 1:

[0058] A method for transforming a power transmission section taking into account power transmission capacity of the present invention is as follows: Figure 1 As shown, the following steps are included:

[0059] S1. Based on the annual operation data of the target transmission section, several typical operating conditions are obtained; the structure of the transmission section is as follows: Figure 2 shown.

[0060] S2. Obtain the load rate extreme value and average load rate of all lines of the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a transmission section power transmission capacity evaluation index system that comprehensively considers the transmission section line operation capacity and the balance degree of the transmission section;

[0061] S3. Under the power transmission capacity evaluation index system of the transmission section, the power transmission capacity of the target transmission section under different typical working conditions is evaluated, and according to the evaluation results, the target transmission section is modified by adding new lines, configuring flexible AC power flow regulation devices or converting to DC.

[0062] Embodiment 2:

[0063] This embodiment is further designed on the basis of the first embodiment in that the calculation method of the load rate extreme value of the target transmission section line under different typical working conditions in this embodiment is as follows:

[0064]

[0065]

[0066] In the formula, μ min,i represents the minimum load rate in the target transmission section under the ith typical operating condition; μ max,i represents the maximum load rate in the target transmission section under the ith typical operating condition; μ t,i represents the load rate of the tth line in the target transmission section under the ith typical operating condition; N is the total number of all transmission lines in the target transmission section; P t,i is the transmission power of the tth line in the target transmission section under the ith typical working condition; P tN is the rated transmission power of the tth line in the target transmission section; M is the total number of typical operating conditions.

[0067] Embodiment three:

[0068] This embodiment is further designed on the basis of the second embodiment in that the calculation method of the average load rate under different typical working conditions in this embodiment is as follows:

[0069]

[0070] In the formula, μ aver,iIt represents the average load rate of all lines in the target transmission section under the i-th typical operating condition.

[0071] Embodiment 4:

[0072] This embodiment is further designed on the basis of the third embodiment in that the calculation method of the power flow entropy of the target transmission section under different typical working conditions in this embodiment is as follows:

[0073]

[0074] Where H i is the power flow entropy of the target transmission section under the i-th typical operating condition; P(k) i is the probability that the line load rate is at (kc, (k+1)c) under the ith typical operating condition; α is a constant coefficient; ln is the logarithmic sign of a natural number; L is the number of load rate interval divisions.

[0075] Embodiment five:

[0076] This embodiment is further designed on the basis of the fourth embodiment in that the probability P(k) of the line load rate being at (kc, (k+1)c) under the i-th typical working condition in this embodiment is i The method to obtain is as follows:

[0077] A constant sequence is constructed to describe the probability level of the target line load, where the constant sequence C is defined as:

[0078] C=[0,c,2c,...,...,kc,...,...,Lc], Lc=100%

[0079] The constant sequence C divides the line load rate into L+1 intervals; c is the set load rate interval range; under the i-th working condition, the probability P(k) that the load rate is in (kc, (k+1)c) is i It can be expressed as:

[0080]

[0081] Where I k,i is the load rate μ under the i-th working condition t,i ∈(kc,(k+1)c).

[0082] Embodiment six:

[0083] This embodiment is further designed on the basis of the fourth embodiment in that the transmission section transmission capacity evaluation index matrix PF of the transmission section power transmission capacity evaluation index system in this embodiment is expressed as:

[0084]

[0085] In the formula, μ min,1 , μ min,2 and μ min,M are the minimum load rates in the target transmission section under the first, second and Mth typical working conditions respectively; μ max,1 , μ max,2 and μ max,M are the maximum load rates in the target transmission section under the first, second and Mth typical operating conditions respectively; μ aver,1 , μ aver,2 and μ aver,M are the average load rates of all lines in the target transmission section under the 1st, 2nd and Mth typical operating conditions respectively; M is the total number of typical operating conditions.

[0086] The column vector in the PF matrix represents the power transmission capacity of the target transmission section under a typical operating condition, and contains evaluation indicators in four dimensions: extreme load factor of all lines, average load factor, and power flow entropy.

[0087] Embodiment seven:

[0088] This embodiment is further designed on the basis of the sixth embodiment in that, in this embodiment, under the power transmission capacity evaluation index system of the transmission section, the power transmission capacity of the target transmission section under different typical working conditions is evaluated, and according to the evaluation result, the specific steps of carrying out the transformation of the target transmission section related to the newly added line, the transformation of configuring the flexible AC power flow regulation device or the transformation of DC conversion include:

[0089] Obtain the maximum load rate μ of the target transmission section under all typical working conditions in the transmission capacity evaluation index matrix PF of the transmission section max,PF , the target transmission section power flow entropy H under the typical working condition corresponding to the maximum load rate PF , the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions μ aver,PF And the maximum value μ of the minimum load factor of the target transmission section under all typical working conditions min,PF ;

[0090] If the maximum load rate μ of the target transmission section under all typical working conditions max,PF The target transmission section power flow entropy H under typical working conditions corresponding to the maximum load rate PF If the following constraints are met, the elements in the row vector representing the maximum load rate of the line are overloaded, and the corresponding power flow entropy is in a balanced state, then the target transmission section does not need to be modified;

[0091] μ max.PF =max{PF(2,:)}<0.8

[0092] H PF <0.5

[0093] Where PF(2,:) is the row vector of the second row of the generated transmission section transmission capacity evaluation index matrix;

[0094] If the maximum value of the minimum load rate of the target transmission section under all typical working conditions is μ min,PF If the following constraints are met, all lines in the target transmission section are in a heavy-load state, and the active power flow regulation capacity between the lines is limited. It is impossible to improve the power transmission capacity of the current target transmission section through the flexible AC / DC power flow regulation device. It is necessary to adopt the transformation method of adding new lines to improve the power transmission capacity of the target transmission section;

[0095] μ min.PF =max{PF(1,:)}>0.8

[0096] Where PF(1,:) is the row vector of the first row of the generated transmission section transmission capacity evaluation index matrix;

[0097] If the maximum load rate μ of the target transmission section under all typical operating conditions max,PF , the target transmission section power flow entropy H under the typical working condition corresponding to the maximum load rate PF , the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions μ aver,PF If the following constraints are met, it means that the maximum load rate of the transmission line under typical working conditions exceeds 0.8, that is, it is in a heavy load state, and the power flow entropy under the typical working condition is greater than 0.5, and the average load rate is less than 0.8, which means that the non-heavy load line in the target transmission section under this working condition has a high power transmission margin. The transformation method of configuring a flexible AC power flow regulation device on the line with the highest load rate can be used to balance the load rate level between lines and reduce the heavy load level of the line;

[0098] μ max.PF =max{PF(2,:)}≥0.8

[0099] H PF ≥0.5

[0100] μ aver.PF ≤0.8

[0101] If the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions, μ aver,PF And the maximum value μ of the minimum load factor of the target transmission section under all typical working conditions min,PFIf the following constraints are met, it means that if the maximum average load rate of all lines in the target transmission section exceeds 0.8 under typical working conditions, that is, multiple transmission lines are in an overloaded state, and the minimum load rate under the typical working condition is less than 0.8. This means that although multiple transmission lines are in an overloaded state, there are still lines that have not reached the overloaded state, that is, the average load rate of the line is high, but there are still working conditions with low load rates. The line corresponding to the minimum load rate in the target section under such working conditions can be selected for DC transformation. This method can improve the overall transmission capacity of the target transmission section and give full play to the flexible power flow control performance of the DC system.

[0102] μ aver.PF =max{PF(3,:)}>0.8

[0103] μ min.PF ≤0.8.

[0104] Embodiment eight:

[0105] A power transmission section transformation system considering power transmission capacity of the present invention comprises a typical working condition acquisition module, a system construction module and an evaluation and transformation module;

[0106] The typical operating condition acquisition module is used to acquire several typical operating conditions based on the annual operation data of the target transmission section;

[0107] The system construction module is used to obtain the load rate extreme value and average load rate of all lines of the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a transmission section power transmission capacity evaluation index system that comprehensively considers the transmission section line operation capacity and the balance degree of the transmission section;

[0108] The evaluation and transformation module is used to evaluate the power transmission capacity of the target transmission section under different typical working conditions under the power transmission capacity evaluation index system of the transmission section, and to carry out the transformation of the target transmission section related to the addition of new lines, the configuration of flexible AC power flow regulation devices or the transformation to DC according to the evaluation results.

[0109] Embodiment nine:

[0110] An electronic device includes a memory and a processor, wherein the memory stores a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method described in any of the above embodiments.

[0111] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in any of the above embodiments are implemented.

[0112] Application examples:

[0113] In this example, the method of the present invention is implemented in a simulation of a certain transmission section to improve the power transmission capacity of the transmission section. Figure 3 and Figure 4 As shown in the figure, this example takes an important power transmission section of a city power grid as the research object, which contains four transmission lines. Four modes of summer small, summer large, winter small, and winter large are selected as typical operating conditions, and the minimum load rate, maximum load rate, average load rate, and power flow entropy of the transmission section line under all typical conditions are calculated respectively. The expression of the transmission capacity evaluation index matrix PF generated by the transmission section is:

[0114]

[0115] The maximum load rate of the target transmission section in the above evaluation index matrix occurs in the summer condition, where μmax,PF is 0.83, satisfying μ max.PF = max{PF(2,:)}≥0.8, and the minimum load rate μ of the target transmission section under this condition min,PF It is 0.52. This shows that although there are many transmission lines in the transmission section that are in a heavy-load state, there are still lines that are not in a heavy-load state, and the DC transformation scheme proposed in this patent can be implemented. The specific DC transformation line is the lightest-load line.

[0116] After the DC transformation of the transmission line is completed, the line load rate and related transmission capacity evaluation indicators under the four typical operation modes of summer low load, summer high load, winter low load and winter high load are calculated again. The specific expression of the evaluation indicator matrix PF' is:

[0117]

[0118] The maximum load rate of all typical working conditions in the modified matrix and its corresponding power flow entropy are less than 0.8 and 0.5 respectively, which meets the μ set in this paper. max.PF =max{PF(2,:)}<0.8、H PF The requirement of <0.5 is met, and the overall operating capacity of the transmission section is good, without the need to add lines or AC / DC flow condition devices.

[0119] The above description is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for transforming a power transmission section considering power transmission capacity, characterized in that: include: Based on the annual operation data of the target transmission section, several typical operating conditions are obtained; Obtain the load rate extreme value and average load rate of all lines in the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a transmission section power transmission capacity evaluation index system that comprehensively considers the transmission section line operation capacity and the balance degree of the transmission section; Under the transmission section power transmission capacity evaluation index system, the power transmission capacity of the target transmission section under different typical working conditions is evaluated, and based on the evaluation results, the target transmission section is modified by adding new lines, configuring flexible AC power flow regulation devices, or converting to DC.

2. The method for transforming a power transmission section considering power transmission capacity according to claim 1, characterized in that: The calculation method of the load rate extreme value of the target transmission section line under different typical working conditions is as follows: In the formula, μ min,i represents the minimum load rate in the target transmission section under the ith typical operating condition; μ max,i represents the maximum load rate in the target transmission section under the ith typical operating condition; μ t,i represents the load rate of the tth line in the target transmission section under the ith typical operating condition; N is the total number of all transmission lines in the target transmission section; P t,i is the transmission power of the tth line in the target transmission section under the ith typical working condition; P tN is the rated transmission power of the tth line in the target transmission section; M is the total number of typical operating conditions.

3. The method for power transmission section reconstruction considering power transmission capacity according to claim 2 is characterized in that: The calculation method of the average load rate under different typical working conditions is as follows: In the formula, μ aver,i It represents the average load rate of all lines in the target transmission section under the i-th typical operating condition.

4. The method for transforming a power transmission section considering power transmission capacity according to claim 3 is characterized in that: The calculation method of the power flow entropy of the target transmission section under different typical working conditions is as follows: Where H i is the power flow entropy of the target transmission section under the i-th typical operating condition; P(k) i is the probability that the line load rate is at (kc, (k+1)c) under the ith typical operating condition; α is a constant coefficient; ln is the logarithmic sign of a natural number; L is the number of load rate interval divisions.

5. The method for power transmission section reconstruction considering power transmission capacity according to claim 4 is characterized in that: The probability P(k) that the line load rate is at (kc, (k+1)c) under the i-th typical operating condition i The method to obtain is as follows: A constant sequence is constructed to describe the probability level of the target line load, where the constant sequence C is defined as: C=[0,c,2c,...,...,kc,...,...,Lc], Lc=100% The constant sequence C divides the line load rate into L+1 intervals; c is the set load rate interval range; under the i-th working condition, the probability P(k) that the load rate is in (kc, (k+1)c) is i It can be expressed as: Where I k,i is the load rate μ under the i-th working condition t,i ∈(kc,(k+1)c).

6. The method for transforming a power transmission section considering power transmission capacity according to claim 4, characterized in that: The transmission section transmission capacity evaluation index matrix PF of the transmission section power transmission capacity evaluation index system is expressed as: In the formula, μ min,1 , μ min,2 and μ min,M are the minimum load rates in the target transmission section under the first, second and Mth typical working conditions respectively; μ max,1 , μ max,2 and μ max,M are the maximum load rates in the target transmission section under the first, second and Mth typical operating conditions respectively; μ aver,1 , μ aver,2 and μ aver,M are the average load rates of all lines in the target transmission section under the 1st, 2nd and Mth typical operating conditions respectively; M is the total number of typical operating conditions.

7. The method for power transmission section reconstruction considering power transmission capacity according to claim 6, characterized in that: The specific steps of evaluating the power transmission capacity of the target transmission section under different typical working conditions under the power transmission capacity evaluation index system of the transmission section, and performing the transformation of the target transmission section related to the newly added line, the transformation of the configuration of the flexible AC power flow regulation device, or the transformation of the DC conversion according to the evaluation results include: Obtain the maximum load rate μ of the target transmission section under all typical working conditions in the transmission capacity evaluation index matrix PF of the transmission section max,PF , the target transmission section power flow entropy H under the typical working condition corresponding to the maximum load rate PF , the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions μ aver,PF And the maximum value μ of the minimum load factor of the target transmission section under all typical working conditions min,PF ; If the maximum load rate μ of the target transmission section under all typical working conditions max,PF The target transmission section power flow entropy H under typical working conditions corresponding to the maximum load rate PF If the following constraints are met, the target transmission section does not need to be modified; m max.PF =max{PF(2,:)}<0.8 H PF ＜0.5 Where PF(2,:) is the row vector of the second row of the generated transmission section transmission capacity evaluation index matrix; If the maximum value of the minimum load rate of the target transmission section under all typical working conditions is μ min,PF If the following constraints are met, the power transmission capacity of the target transmission section will be improved by adding new lines for transformation; m min.PF =max{PF(1,:)}>0.8 Where PF(1,:) is the row vector of the first row of the generated transmission section transmission capacity evaluation index matrix; If the maximum load rate μ of the target transmission section under all typical working conditions max,PF , the target transmission section power flow entropy H under the typical working condition corresponding to the maximum load rate PF , the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions μ aver,PF If the following constraints are met, the load level between lines is balanced by using a flexible AC power flow regulator on the line with the highest load rate; m max.PF =max{PF(2,:)}≥0.8 H PF ≥0.5 m aver.PF ≤0.8 If the maximum load rate corresponds to the average load rate of all lines in the target transmission section under typical working conditions, μ aver,PF And the maximum value μ of the minimum load factor of the target transmission section under all typical working conditions min,PF Satisfying the following constraints, select the line corresponding to the minimum load rate in the target section under the typical working condition for DC transformation; m aver.PF =max{PF(3,:)}>0.8 m min.PF ≤0.8。 8. A power transmission section transformation system considering power transmission capacity, characterized in that: It includes typical working condition acquisition module, system construction module and evaluation and transformation module; The typical operating condition acquisition module is used to acquire several typical operating conditions based on the annual operation data of the target transmission section; The system construction module is used to obtain the load rate extreme value and average load rate of all lines of the target transmission section under different typical working conditions and the power flow entropy of the target transmission section, thereby constructing a transmission section power transmission capacity evaluation index system that comprehensively considers the transmission section line operation capacity and the balance degree of the transmission section; The evaluation and transformation module is used to evaluate the power transmission capacity of the target transmission section under different typical working conditions under the power transmission capacity evaluation index system of the transmission section, and to carry out the transformation of the target transmission section related to the addition of new lines, the configuration of flexible AC power flow regulation devices or the transformation to DC according to the evaluation results.

9. An electronic device, characterized in that: The electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor is configured to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method as claimed in any one of claims 1 to 7 are implemented.

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