Setting mismatch optimization method combining relay protection setting principle

Abstract

A setting mismatch optimization method combining a relay protection setting principle comprises the following steps: 1) obtaining an initial power network structure, and defining a mismatch variable and an auxiliary variable of a protection cooperation relationship; 2) based on the auxiliary variables, constructing a setting optimization model based on the importance of the minimum mismatch relationship; 3) based on a relay protection setting principle, performing constraint processing on the setting optimization model based on the minimum mismatch relationship importance to obtain a setting optimization model after constraint processing; 4) solving the setting optimization model after constraint processing based on a genetic algorithm to obtain an optimized mismatch variable and a constant value optimization result; and 5) based on the optimized mismatch variable and the fixed value optimization result, the same-section matching ring during action time setting is solved through an action time setting optimization method, and a final setting optimization scheme is generated. According to the method, action time setting optimization is considered, and action time is ensured not to exceed the upper limit, so that the problem of overlong delay coordination chain is avoided, and safe and stable operation of a power grid is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system and its automation technology, in particular to a setting mismatch optimization method combined with relay protection setting principle. BACKGROUND

[0002] In the process of relay protection setting of power system, it is essential to ensure the coordination between each protection device. Due to the complex topology of power network, it is difficult to ensure the complete cooperation of each protection, and to a large extent, the selectivity or speed will be sacrificed to meet the sensitivity requirements, resulting in protection mismatch. When the fault occurs in the line of the protection mismatch point, the protection may overstep the action, which may expand the accident range or cause damage to the power grid, resulting in loss.

[0003] The current setting optimization method mostly takes the shortest protection setting action time as the optimization target, and combines the protection sensitivity, selectivity and other constraint conditions, but does not focus on the optimization of setting mismatch. For the same segment loop coordination problem in ring network structure, the existing method solves the problem by selecting the minimum breakpoint set and the minimum protection mismatch relationship set as the setting starting point, but this scheme does not consider the network impedance parameters, reliability coefficients, sensitivity coefficients, and auxiliary increase coefficients required for setting, and can only be used to determine the optimal setting starting point and protection setting sequence during manual setting. The specific defects are as follows: first, the initial purpose of starting point selection is to break all simple directed loops to avoid the situation that the same segment loop coordination leads to the inability to set, but not all protection coordination relationships in the loop are the same segment loop coordination, and to a large extent, there are protections that can be coordinated with the lower level protection speed segment on the setting value, thereby breaking the loop coordination, and the specific situation is related to network parameters and setting coefficients; second, only the optimization of the minimum mismatch relationship set is performed when the starting point is selected to assist manual setting, but the number of mismatch relationships is not optimized during specific setting; third, the minimum mismatch relationship set selected by optimization only considers the corresponding coordination relationship during setting, but whether the mismatch exists on the setting value is unknown, and the coordination may still exist. SUMMARY

[0004] The purpose of the present application is to provide a setting mismatch optimization method combined with relay protection setting principle, comprising the following steps:

[0005] 1) Obtain the initial power network structure, and define the mismatch variable and auxiliary variable of the protection coordination relationship in the initial power network structure.

[0006] 2) Based on the auxiliary variable, a setting optimization model based on the importance of the minimum mismatch relationship is constructed.

[0007] 3) Based on the relay protection setting principle, the setting optimization model based on the importance of the minimum mismatch relationship is subjected to constraint processing to obtain the constraint-processed setting optimization model.

[0008] 4) Solve the constrained tuning optimization model based on the genetic algorithm to obtain the optimized mismatch variables and the fixed value optimization results.

[0009] 5) Based on the optimized mismatch variables and the optimization results of the setpoints, the same-segment coordination loops during action time tuning are solved by the action time tuning optimization method, and the final tuning optimization scheme is generated.

[0010] Furthermore, the mismatch variables and auxiliary variables of the protection coordination relationship in the initial power network structure are as follows:

[0011] (1)

[0012] (2)

[0013] In the formula, This represents the set of mismatched variables. This represents a set of auxiliary variables. , They represent the first Mismatch variables and auxiliary variables in a protective coordination relationship. , Indicates the number of protective cooperation relationships. When When, it indicates the setting command number. A mismatch in the protection relationship. When When, it indicates the setting command number. In the protection coordination relationship, the setting protection and the coordination protection I stage are coordinated. When When, it indicates the setting command number. In the protection coordination relationship, the setting protection and the coordination protection stage II are coordinated. When hour, .when or hour, .

[0014] Furthermore, the objective function of the tuning optimization model based on the minimum mismatch importance is as follows:

[0015] (3)

[0016] In the formula, Indicates the index of protected cooperation relationships. Indicates the number of protective cooperation relationships. Indicates the first An auxiliary variable for protecting the coordination relationship. Indicates the first The importance of a protective and cooperative relationship.

[0017] Furthermore, the constraint condition of the tuning optimization model after constraint processing is that all protection coordination relationships in the mismatch variables are tuned to obtain the set values ​​of all protections.

[0018] The protection includes setting protection, coordinated protection stage I, and coordinated protection stage II.

[0019] The constraint processing steps for coordinating the protection stage II setting are as follows:

[0020] Based on the power network parameters and setting coefficients, a1 calculates the setting values ​​for coordinated protection stage I, the sensitivity requirements for coordinated protection stage II, and the coordination values ​​between the setting protection and coordinated protection stage I in the protection coordination relationship, as shown below:

[0021] (4)

[0022] (5)

[0023] (6)

[0024] In the formula, This indicates the setting value for the protection segment I. This indicates the sensitivity requirement value for the protection stage II. This indicates the coordination value of the set protection and the coordinated protection segment I in the protection coordination relationship. This indicates the reliability coefficient of the coordinated protection stage I. This indicates the positive sequence impedance of the line. This indicates the sensitivity coefficient of the protection stage II. This indicates the reliability coefficient of the coordinated protection stage II. This represents the amplification coefficient.

[0025] Based on the settings of the coordinated protection section I, the sensitivity requirements of the coordinated protection section II, and the coordination values ​​of the set protection and the coordinated protection section I in the protection coordination relationship, the protection coordination relationship with the coordinated protection section I is found, forming the protection coordination relationship set RDRII_I.

[0026] The protection coordination relationship described above, involving the coordination value between the set protection and the coordination protection stage I, is as follows: Not less than the sensitivity requirement value of the protection stage II .

[0027] Step a3 determines whether there exists a protection coordination relationship with a mismatch variable of 2 in the protection coordination relationship set RDRII_I. If yes, proceed to step a4. If no, proceed to step a5.

[0028] a4 calculates the sensitivity requirement values ​​for the setting protection and the coordinated protection stage II in all protection coordination relationships with a mismatch variable of 2 in the protection coordination relationship set RDRII_I, and uses these values ​​as the coordination values ​​for the setting protection and the coordinated protection stage II in the protection coordination relationship. Then proceed to step a5.

[0029] a5 determines whether there is a protective coordination relationship with a mismatch variable of 1. If yes, proceed to step a6; otherwise, proceed to step a9.

[0030] Step a6 determines whether there exists a protection coordination relationship with a mismatch variable of 1 in the protection coordination relationship set RDRII_I. If yes, proceed to step a7. If no, proceed to step a8.

[0031] a7 sets all mismatched variables of 1 in the protection coordination relationship set RDRII_I to the coordination value of the set protection and the coordinated protection segment I. Adjust accordingly and proceed to step a9.

[0032] a8 changes the mismatch variable of all protected coordination relationships where the mismatch variable is 1 to 2, and proceeds to step a9.

[0033] a9 determines whether there is a protective coordination relationship with a mismatch variable of 2. If yes, proceed to step a10; otherwise, proceed to step a12.

[0034] a10 determines whether the protection coordination relationship with all mismatch variables of 2 has been obtained, including the setting of the protection and the coordination value of the second stage of the protection. If yes, proceed to step a11; otherwise, proceed to step a12.

[0035] a11 Determines the setting of protection and coordination values ​​for all mismatched variables of 2 in the protection coordination relationship. Does it meet the sensitivity requirements? If so, then set all mismatched variables of 2 to the protection coordination relationship according to the setting protection and coordinated protection stage II coordination value. If the settings are not met, proceed to step a12. Otherwise, change the mismatch variable of the protection matching relationship that does not meet the sensitivity requirements to 0, and proceed to step a12.

[0036] a12 identifies all protection coordination relationships where the number of coordination protection segments is determined and the coordination values ​​are obtained. Then, it selects the coordination values ​​for the first segment of the protection coordination obtained from all iterations. and coordination protection stage II coordination value The minimum value is used as the set value for the second stage of coordinated protection in the coordinated protection relationship. .

[0037] a13 Determines the appropriate protection stage II setting value Is there a difference compared to the previous iteration? If yes, return to step a9; otherwise, proceed to step a14.

[0038] a14 Determines whether there is a coordinated protection stage II setting. If the protection is not set, proceed to step a15; otherwise, proceed to step a16.

[0039] a15 sets the protection level for stage II. The mismatch variable for untuned protection coordination relationships is changed to 0.

[0040] a16 obtains the setpoints and corresponding mismatch variables for all coordinated protection stage II.

[0041] Furthermore, the sensitivity requirements for the set protection and the coordinated protection stage II in the protection coordination relationship are as follows:

[0042] (7)

[0043] In the formula, This indicates the sensitivity requirement value for the set protection and the coordinated protection stage II in the protection coordination relationship. This indicates the sensitivity requirement value for the protection stage II. This indicates the positive sequence impedance of the line. This indicates the reliability coefficient of the coordinated protection stage II. This represents the amplification coefficient.

[0044] Furthermore, the sensitivity requirements are as follows:

[0045] (8)

[0046] In the formula, This indicates the sensitivity requirement value for the protection stage II. This indicates the coordination value of the set protection and the coordinated protection segment I in the protection coordination relationship. This indicates the sensitivity requirement value for the set protection and the coordinated protection stage II in the protection coordination relationship. This indicates the coordination value between the set protection and the coordinated protection stage II in the protection coordination relationship.

[0047] Furthermore, in step 4), the steps for obtaining the optimized mismatch variables and the fixed-value optimization results are as follows:

[0048] b1 is based on the tuned optimization model after constraint processing, forming the fitness function.

[0049] b2 defines the set of mismatch variables. For each individual, initialize the population and the number of iterations.

[0050] b3 calculates the fitness of each individual in the population and updates it to obtain the individual with the best fitness.

[0051] b4 forms a new generation of population through selection, crossover, and mutation.

[0052] b5 checks if the maximum number of iterations has been reached. If not, increment the iteration count and return to step b3. If yes, proceed to step b6.

[0053] b6 yields the optimized mismatch variables and the constant value optimization results.

[0054] Furthermore, in step 5), the steps for generating the final tuning optimization scheme are as follows:

[0055] c1 constructs the protection correlation matrix RIM based on the optimized mismatch variables.

[0056] The rows and columns in the Protection Association Matrix (RIM) represent the protection in the initial power network structure, and the elements... This indicates the coordination relationship between the s-th protection and the t-th protection. This indicates that the s-th protection does not cooperate with the t-th protection, when This indicates the coordination between the s-th protection and the t-th protection.

[0057] c2 removes elements from the protected association matrix RIM. The updated protection association matrix RIM is obtained by combining rows and columns with all zeros.

[0058] c3 checks if an element exists in the updated protection association matrix RIM. If a row or column contains all zeros, then return the updated protected association matrix RIM to step c2; otherwise, proceed to step c4.

[0059] c4 determines whether the updated protection association matrix RIM is an empty set. If yes, proceed to step c6; otherwise, proceed to step c5.

[0060] c5 determines the remaining elements in the updated protected association matrix RIM. The corresponding protection coordination relationship is directly disconnected, and the corresponding mismatch variable is updated to 1, proceeding to step c6.

[0061] c6 uses the motion time tuning optimization method to solve the same-segment coordination loop during motion time tuning and generates the final tuning optimization scheme.

[0062] Furthermore, in step c6, the steps for resolving the same-segment coordination loop during motion time tuning using the motion time tuning optimization method are as follows:

[0063] c61 removes mismatched protection pairings based on the updated mismatch variables.

[0064] Based on the optimization results, c62 determines the operating time of stage II of the coordinated protection for protection without coordination relationship. The protection coordination relationship and time coordination value with the coordinated protection segment I. .

[0065] For protections with existing protection coordination relationships and time coordination values, c63 selects the maximum value as the coordinated protection stage II operating time. And update the time coordination value of the protection coordination relationship with the coordination protection stage II, whether it is coordinated or mismatched. .

[0066] c64 determines whether all protections are obtained during the coordinated protection stage II action time. If not, return to step c63; if yes, proceed to step c65.

[0067] c65 protects the time coordination value of the coordination relationship. If the protection coordination relationship exceeds the preset value, there will be a time mismatch, and the coordination protection stage II action time of each protection will be updated. .

[0068] After C66 is set, the coordination of each protection system and the operation time of protection stage II are determined. In addition to the mismatch variables of each protection in terms of action time, the final tuning optimization scheme is generated.

[0069] Furthermore, the time coordination value of the protection coordination relationship with the coordination protection stage II, whether it is coordinated or mismatched. The update formula is as follows:

[0070] (9)

[0071] In the formula, Indicates time level difference, This represents the maximum action time among all cooperating protection actions.

[0072] The technical effect of this invention is undeniable. The tuning mismatch optimization method proposed in this invention optimizes whether the protection matches or not and the number of matching segments in the tuning process. It can automatically generate tuning optimization schemes with the lowest overall protection mismatch relationship importance and the fewest number, thus effectively solving the tuning mismatch problem.

[0073] This invention incorporates the actual relay protection setting process into the constraint processing, determines whether protection coordination is required and the number of coordination segments through setting calculations, and ensures the feasibility and effectiveness of setting mismatch optimization.

[0074] This invention takes into account the optimization of action time setting to ensure that the action time does not exceed the upper limit, thereby avoiding the problem of excessively long delay coordination chain and making it more conducive to the safe and stable operation of the power grid.

[0075] This invention can be applied to the setting optimization process of power system relay protection.

[0076] This invention incorporates constraint processing into the tuning process. Through tuning calculations, it determines whether protection coordination is required and the number of coordination segments. It optimizes the number and importance of mismatch relationships in the tuning results, obtaining a tuning mismatch optimization model. A genetic algorithm is then used to solve this model. Based on the optimization results, the coordination between each protection is determined. Next, the operating time is optimized. A tuning start point optimization model is used to untangle the same-segment coordination loops during operating time tuning. Furthermore, an operating time tuning process is added to ensure that the operating time is not too long, ultimately resulting in a tuning optimization scheme with the fewest overall protection mismatch relationships and the lowest importance. Attached Figure Description

[0077] Figure 1 This is a flowchart of the present invention;

[0078] Figure 2 A schematic diagram illustrating the constraint processing process of the grounding distance protection stage II setting mismatch optimization model;

[0079] Figure 3 A schematic diagram illustrating the constraint processing procedure for the motion time tuning optimization model;

[0080] Figure 4 This is a schematic diagram of the 220KV main network topology in a certain region. Detailed Implementation

[0081] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0082] Example 1:

[0083] See Figures 1 to 4 A method for optimizing setting mismatch based on relay protection setting principles includes the following steps:

[0084] 1) Obtain the initial power network structure and define the mismatch variables and auxiliary variables of the protection coordination relationship in the initial power network structure.

[0085] 2) Based on auxiliary variables, construct an optimization model based on the importance of minimum mismatch relationship.

[0086] 3) Based on the relay protection setting principle, the setting optimization model based on the importance of minimum mismatch relationship is constrained to obtain the set optimization model after constraint processing.

[0087] 4) Solve the constrained tuning optimization model based on the genetic algorithm to obtain the optimized mismatch variables and the fixed value optimization results.

[0088] 5) Based on the optimized mismatch variables and the optimization results of the setpoints, the same-segment coordination loops during action time tuning are solved by the action time tuning optimization method, and the final tuning optimization scheme is generated.

[0089] Example 2:

[0090] A setting mismatch optimization method combining relay protection setting principles is described in Example 1. Further, the mismatch variables and auxiliary variables of the protection coordination relationship in the initial power network structure are as follows:

[0091] (1)

[0092] (2)

[0093] In the formula, This represents the set of mismatched variables. This represents a set of auxiliary variables. , They represent the first Mismatch variables and auxiliary variables in a protective coordination relationship. , Indicates the number of protective cooperation relationships. When When, it indicates the setting command number. A mismatch in the protection relationship. When When, it indicates the setting command number. In the protection coordination relationship, the setting protection and the coordination protection I stage are coordinated. When When, it indicates the setting command number. In the protection coordination relationship, the setting protection and the coordination protection stage II are coordinated. When hour, .when or hour, .

[0094] Example 3:

[0095] A setting mismatch optimization method combining relay protection setting principles is described in any one of Embodiments 1 and 2. Further, the objective function of the setting optimization model based on the minimum mismatch relationship importance is as follows:

[0096] (3)

[0097] In the formula, Indicates the index of protected cooperation relationships. Indicates the number of protective cooperation relationships. Indicates the first An auxiliary variable for protecting the coordination relationship. Indicates the first The importance of a protective and cooperative relationship.

[0098] Example 4:

[0099] A setting mismatch optimization method combining relay protection setting principles is provided. The main technical contents are described in any one of Examples 1 to 3. Further, the constraint condition of the setting optimization model after constraint processing is that all protection coordination relationships in the mismatch variable are calculated to obtain the setting values ​​of all protections through setting.

[0100] The protection includes setting protection, coordinated protection stage I, and coordinated protection stage II.

[0101] The constraint processing steps for coordinating the protection stage II setting are as follows:

[0102] Based on the power network parameters and setting coefficients, a1 calculates the setting values ​​for coordinated protection stage I, the sensitivity requirements for coordinated protection stage II, and the coordination values ​​between the setting protection and coordinated protection stage I in the protection coordination relationship, as shown below:

[0103] (4)

[0104] (5)

[0105] (6)

[0106] In the formula, This indicates the setting value for the protection segment I. This indicates the sensitivity requirement value for the protection stage II. This indicates the coordination value of the set protection and the coordinated protection segment I in the protection coordination relationship. This represents the reliability coefficient of the coordinated protection stage I, which is generally taken as 0.6~0.7. This indicates the positive sequence impedance of the line. This indicates the sensitivity coefficient of the protection stage II. The following routes ; The following routes ; The following routes ; The following routes ; The above routes . This represents the reliability coefficient of the coordinated protection stage II, with a value of 0.7. This represents the amplification factor. In multi-source systems, the setting coordination between adjacent upstream and downstream protection systems may be affected by intermediate amplification power sources, causing the measured impedance of the upstream protection to increase or decrease, and the corresponding protection range to shorten or lengthen. Therefore, an amplification factor needs to be introduced into the setting formula. Its value is the ratio of the fault current of the downstream coordinated line to the current of the current line at this level. When setting the coordination, the smallest possible amplification factor should be selected. The specific value is related to the network parameters and operating mode, and it measures the influence of branch lines on the fault measurement impedance on the opposite bus.

[0107] Based on the settings of the coordinated protection section I, the sensitivity requirements of the coordinated protection section II, and the coordination values ​​of the set protection and the coordinated protection section I in the protection coordination relationship, the protection coordination relationship with the coordinated protection section I is found, forming the protection coordination relationship set RDRII_I.

[0108] The protection coordination relationship described above, involving the coordination value between the set protection and the coordination protection stage I, is as follows: Not less than the sensitivity requirement value of the protection stage II .

[0109] Step a3 determines whether there exists a protection coordination relationship with a mismatch variable of 2 in the protection coordination relationship set RDRII_I. If yes, proceed to step a4. If no, proceed to step a5.

[0110] a4 calculates the sensitivity requirement values ​​for the setting protection and the coordinated protection stage II in all protection coordination relationships with a mismatch variable of 2 in the protection coordination relationship set RDRII_I, and uses these values ​​as the coordination values ​​for the setting protection and the coordinated protection stage II in the protection coordination relationship. Then proceed to step a5.

[0111] a5 determines whether there is a protective coordination relationship with a mismatch variable of 1. If yes, proceed to step a6; otherwise, proceed to step a9.

[0112] Step a6 determines whether there exists a protection coordination relationship with a mismatch variable of 1 in the protection coordination relationship set RDRII_I. If yes, proceed to step a7. If no, proceed to step a8.

[0113] a7 sets all mismatched variables of 1 in the protection coordination relationship set RDRII_I to the coordination value of the set protection and the coordinated protection segment I. Adjust accordingly and proceed to step a9.

[0114] a8 changes the mismatch variable of all protected coordination relationships where the mismatch variable is 1 to 2, and proceeds to step a9.

[0115] a9 determines whether there is a protective coordination relationship with a mismatch variable of 2. If yes, proceed to step a10; otherwise, proceed to step a12.

[0116] a10 determines whether the protection coordination relationship with all mismatch variables of 2 has been obtained, including the setting of the protection and the coordination value of the second stage of the protection. If yes, proceed to step a11; otherwise, proceed to step a12.

[0117] a11 Determines the setting of protection and coordination values ​​for all mismatched variables of 2 in the protection coordination relationship. Does it meet the sensitivity requirements? If so, then set all mismatched variables of 2 to the protection coordination relationship according to the setting protection and coordinated protection stage II coordination value. If the settings are not met, proceed to step a12. Otherwise, change the mismatch variable of the protection matching relationship that does not meet the sensitivity requirements to 0, and proceed to step a12.

[0118] a12 identifies all protection coordination relationships where the number of coordination protection segments is determined and the coordination values ​​are obtained. Then, it selects the coordination values ​​for the first segment of the protection coordination obtained from all iterations. and coordination protection stage II coordination value The minimum value is used as the set value for the second stage of coordinated protection in the coordinated protection relationship. .

[0119] a13 Determines the appropriate protection stage II setting value Is there a difference compared to the previous iteration? If yes, return to step a9; otherwise, proceed to step a14.

[0120] a14 Determines whether there is a coordinated protection stage II setting. If the protection is not set, proceed to step a15; otherwise, proceed to step a16.

[0121] a15 sets the protection level for stage II. The mismatch variable for untuned protection coordination relationships is changed to 0.

[0122] a16 obtains the setpoints and corresponding mismatch variables for all coordinated protection stage II.

[0123] Example 5:

[0124] A method for optimizing setting mismatch based on relay protection setting principles is described in any one of Examples 1 to 4. Further, the sensitivity requirements for the setting protection and the coordinated protection stage II in the protection coordination relationship are as follows:

[0125] (7)

[0126] In the formula, This indicates the sensitivity requirement value for the set protection and the coordinated protection stage II in the protection coordination relationship. This indicates the sensitivity requirement value for the protection stage II. This indicates the positive sequence impedance of the line. This indicates the reliability coefficient of the coordinated protection stage II. This represents the amplification coefficient.

[0127] Example 6:

[0128] A setting mismatch optimization method combining relay protection setting principles, the main technical contents of which are described in any one of Examples 1 to 5, and further, the sensitivity requirements are as follows:

[0129] (8)

[0130] In the formula, This indicates the sensitivity requirement value for the protection stage II. This indicates the coordination value of the set protection and the coordinated protection segment I in the protection coordination relationship. This indicates the sensitivity requirement value for the set protection and the coordinated protection stage II in the protection coordination relationship. This indicates the coordination value between the set protection and the coordinated protection stage II in the protection coordination relationship.

[0131] Example 7:

[0132] A setting mismatch optimization method combining relay protection setting principles is described in any one of Examples 1 to 6. Further, in step 4), the steps for obtaining the optimized mismatch variables and setting optimization results are as follows:

[0133] b1 is based on the tuned optimization model after constraint processing, forming the fitness function.

[0134] b2 defines the set of mismatch variables. For each individual, initialize the population and the number of iterations.

[0135] b3 calculates the fitness of each individual in the population and updates it to obtain the individual with the best fitness.

[0136] b4 forms a new generation of population through selection, crossover, and mutation.

[0137] b5 checks if the maximum number of iterations has been reached. If not, increment the iteration count and return to step b3. If yes, proceed to step b6.

[0138] b6 yields the optimized mismatch variables and the constant value optimization results.

[0139] Example 8:

[0140] A method for optimizing setting mismatch based on relay protection setting principles, the main technical contents of which are described in any one of Examples 1 to 7, further, in step 5), the steps for generating the final setting optimization scheme are as follows:

[0141] c1 constructs the protection correlation matrix RIM based on the optimized mismatch variables.

[0142] The rows and columns in the Protection Association Matrix (RIM) represent the protection in the initial power network structure, and the elements... This indicates the coordination relationship between the s-th protection and the t-th protection. This indicates that the s-th protection does not cooperate with the t-th protection, when This indicates the coordination between the s-th protection and the t-th protection.

[0143] c2 removes elements from the protected association matrix RIM. The updated protection association matrix RIM is obtained by combining rows and columns with all zeros.

[0144] c3 checks if an element exists in the updated protection association matrix RIM. If a row or column contains all zeros, then return the updated protected association matrix RIM to step c2; otherwise, proceed to step c4.

[0145] c4 determines whether the updated protection association matrix RIM is an empty set. If yes, proceed to step c6; otherwise, proceed to step c5.

[0146] c5 determines the remaining elements in the updated protected association matrix RIM. The corresponding protection coordination relationship is directly disconnected, and the corresponding mismatch variable is updated to 1, proceeding to step c6.

[0147] c6 uses the motion time tuning optimization method to solve the same-segment coordination loop during motion time tuning and generates the final tuning optimization scheme.

[0148] Example 9:

[0149] A setting mismatch optimization method combining relay protection setting principles, the main technical contents of which are described in any one of embodiments 1 to 8. Further, in step c6, the step of untying the same-segment coordination loop during the operating time setting by the operating time setting optimization method is as follows:

[0150] c61 removes mismatched protection pairings based on the updated mismatch variables.

[0151] Based on the optimization results, c62 determines the operating time of stage II of the coordinated protection for protection without coordination relationship. The protection coordination relationship and time coordination value with the coordinated protection segment I. .

[0152] For protections with existing protection coordination relationships and time coordination values, c63 selects the maximum value as the coordinated protection stage II operating time. And update the time coordination value of the protection coordination relationship with the coordination protection stage II, whether it is coordinated or mismatched. .

[0153] c64 determines whether all protections are obtained during the coordinated protection stage II action time. If not, return to step c63; if yes, proceed to step c65.

[0154] c65 protects the time coordination value of the coordination relationship. If the protection coordination relationship exceeds the preset value, there will be a time mismatch, and the coordination protection stage II action time of each protection will be updated. .

[0155] After C66 is set, the coordination of each protection system and the operation time of protection stage II are determined. In addition to the mismatch variables of each protection in terms of action time, the final tuning optimization scheme is generated.

[0156] Example 10:

[0157] A method for optimizing setting mismatch based on relay protection setting principles, the main technical contents of which are described in any one of Examples 1 to 9, further comprising the time coordination value of the protection coordination relationship with the coordinated protection stage II for coordination or mismatch. The update formula is as follows:

[0158] (9)

[0159] In the formula, Indicates time level difference, This represents the maximum action time among all cooperating protection actions.

[0160] Example 11:

[0161] See Figures 1 to 4 A method for optimizing setting mismatch based on relay protection setting principles, the main technical contents of which include:

[0162] First, a setting optimization model based on the minimum importance of mismatch relationships is constructed. The selection of whether protection coordination is required and the number of coordination segments are determined through setting calculations. The optimization objective is to minimize the number of mismatch relationships or the sum of their importance in the setting results. A genetic algorithm is used to solve the setting optimization model to obtain the setting optimization results. Based on the setting optimization results, the action time setting is optimized, untangling the same-segment coordination loops during action time setting and ensuring that the action time does not exceed the upper limit, generating a setting optimization scheme with the lowest overall protection mismatch relationship importance and the fewest number. Finally, the optimization effect is verified through example simulation, validating the application effect of this method in complex power networks and verifying the effectiveness of the proposed optimization of protection setting values ​​by considering relay protection setting principles.

[0163] The details are as follows.

[0164] 1. Establish a tuning optimization model based on the importance of minimum mismatch relationships.

[0165] This invention takes the setting of the second stage of grounding distance protection as an example, incorporating the setting process into constraint processing, and determining whether protection coordination is necessary and the number of coordination stages through setting calculations. An optimization model is constructed with the goal of minimizing the number of mismatch relationships or the sum of their importance in the setting results. First, decision variables are defined. Its elements ,in The number of protective cooperation relationships in the network. The elements still correspond sequentially to each protection coordination relationship, while the element values ​​correspond to whether the protection coordination relationship in the network is mismatched or the number of coordination segments. A value of 0 indicates the setting instruction number. A mismatch in the protection and coordination relationship Let 1 represent the first... In the protection coordination relationship, the setting protection and the coordination protection I segment are coordinated. Let 2 represent the first... In the protection coordination relationship, the setting protection and the coordination protection II stage are coordinated. The value of the element is just an initial selection. It is used to randomly generate a certain number of candidate solutions to form the initial population when using the genetic algorithm to solve the problem. It still needs to be constrained before it can be used to calculate the objective function.

[0166] To facilitate the definition of the objective function, auxiliary variables are added. Used to measure the number of mismatch relationships, its elements Corresponding in order If the elements in the middle, A value of 0 indicates a mismatch in the corresponding fit relationship. If it is 1; A value of 1 or 2 indicates a corresponding coordination relationship. It is 0.

[0167] The objective function of the tuning optimization model that minimizes the number of tuning mismatches is shown in equation (1):

[0168] (1)

[0169] The objective function of the tuning optimization model that combines the importance of the protection coordination relationship is shown in equation (2):

[0170] (2)

[0171] in, For the first The importance of the protective and cooperative relationship.

[0172] 2. Constraint Handling Strategy for Tuning Optimization Model Based on Minimum Mismatch Relationship Importance

[0173] The actual setting process of relay protection is incorporated into the constraint processing. Setting calculations determine whether protection coordination is required and the number of coordination stages, ultimately leading to the setting values ​​of each protection unit. The constraints of the setting optimization model are the selected decision variables. The corresponding coordination of each protection can determine the settings of all protections in the system. Taking the setting of the second stage of grounding distance protection as an example, when the number of coordination stages for each coordination relationship of a protection has been determined and the corresponding coordination values ​​have been calculated, its second stage setting value... It can be calculated that, for grounding distance protection, the minimum value among all coordination values ​​should be selected as the second-stage setting value of the protection. The constraint handling strategy for optimizing the setting of the second-stage setting value of grounding distance protection is as follows:

[0174] (1) First, calculate the setting value of each protection stage I based on the power network parameters and setting coefficients. Sensitivity requirements for each protection stage II In each protection coordination relationship, the coordination value of the set protection and the coordinated protection segment I. These values ​​can all be calculated based on the setting principles and required parameters, serving as initial conditions. The coordination values ​​between the setting protection and the coordinated protection stage II in each coordination relationship... The second-stage setting needs to be coordinated with the protection. Calculations can only be performed after the settings are configured.

[0175] (2) Based on the constant value calculated in (1), find the protection coordination relationships that can coordinate with the first stage of the protection. The first stage coordination value of these coordination relationships. It shall not be less than the sensitivity requirement value of its set protection stage II. ,Right now This meets the sensitivity requirements. The set of protection coordination relationships that can coordinate with the first stage of the protection system is denoted as RDRII_I.

[0176] (3) For RDRII_I, if it exists The initial selection of 2, which corresponds to the coordination relationship with the second stage of the protection, allows for setting the sensitivity requirement value of the second stage of the protection and the coordinated protection in the corresponding protection coordination relationship. Cooperation, denoted as Because in these protection coordination relationships, the setting protection can coordinate with the coordinated protection stage I, that is, there is According to the setting principle, if the setting value of each protection stage I is less than the sensitivity requirement value of its stage II, then in these protection coordination relationships, the set protection can also coordinate with the sensitivity requirement value of the stage II protection, that is, there is Therefore, these protection coordination relationships can be viewed as coordination with the second stage of the protection, and the corresponding second stage coordination values. That is .

[0177] (4) For decision variables The initial selection is 1, which corresponds to the coordination relationship with the protection segment I. If this coordination relationship is in RDRII_I, then the coordination relationship is set according to the coordination with segment I; if the coordination relationship is not in RDRII_I, then... The corresponding element value is first changed to 2, indicating that the setting protection and the coordinated protection stage II are coordinated in this protection coordination relationship.

[0178] (5) For decision variables The value of 2 represents the coordination relationship with the second stage of the protection system. If its second stage coordination value is... It can be calculated, that is, the setting value of the second stage of the coordinated protection. If the settings have been configured, check if the sensitivity requirements are met. If they are met, the protection coordination relationship should be configured according to the coordination with Stage II; if not, the coordination relationship should be mismatched, and... The corresponding element value will be set to 0.

[0179] (6) For a protection, if the number of coordination segments for each coordination relationship in its coordination relationship set is determined and the corresponding coordination values ​​are calculated, then its II segment setting value Therefore, it can be calculated that, for grounding distance protection, the minimum value among all coordination values ​​should be selected as the stage II setting value for this protection. The cyclic tuning begins. Based on the coordination relationship set of each protection, the protection with a fixed number of coordination segments and corresponding coordination values ​​for each coordination relationship in the set is identified, and the stage II setting is calculated. Update computable Until no new protection stage II settings are set. Until it can be calculated.

[0180] (7) Final II-stage setpoint Undefined protection necessarily involves undetermined coordination values, meaning there are coordination relationships related to unresolved segment II coordination loops. The remaining coordination values ​​can be related to segment II coordination but not segment II coordination values. Uncalculated matching relationships are directly mismatched, in order to determine the residual protection stage II setting. and in The corresponding element value will be set to 0.

[0181] (8) After the settings are completed, the settings of each protection stage II should be verified. Based on the set values, the final coordination between each protection unit is obtained, and then updated. The value of is used to calculate the objective function.

[0182] 3. Solution method for tuning optimization model based on genetic algorithm

[0183] The solution process for the tuning optimization model based on the minimum mismatch relationship importance is as follows: A genetic algorithm is used to solve the optimization model.

[0184] (1) Set the power network parameters, tuning parameters and initial parameters of the genetic algorithm.

[0185] (2) Calculate the settings for each protection stage I. Sensitivity requirements for each protection stage II In each protection coordination relationship, the coordination value of the set protection and the coordinated protection segment I. .

[0186] (3) Form a set of coordination relationships RDRII_I that can coordinate with the protection segment I.

[0187] (4) The fitness function is formed based on the optimization objective function and the constraint processing procedure.

[0188] (5) Initialize the population and the number of iterations, calculate the fitness of individuals in the initial population, and obtain the individual with the best fitness.

[0189] (6) Perform selection, crossover, and mutation operations to form a new generation of population, obtain the new generation of individuals with the best fitness, update the current individuals with the best fitness, and increment the iteration count by 1.

[0190] (7) Determine whether the maximum number of iterations has been reached. If it is, proceed to the next step; otherwise, jump to the previous step to continue iterating.

[0191] (8) End the process and obtain the decision variable X corresponding to the optimal individual and the set values ​​of each protection stage II. .

[0192] 4. Optimization methods for motion timing tuning

[0193] Based on the optimization results of the setpoints, the operating time is optimized. The optimization model of the setting starting point is used to solve the coordination loops within the same segment when setting the operating time. On this basis, the operating time setting process is added to ensure that the operating time is not too long. Finally, the coordination between each protection is determined, and the setting result with the lowest importance and fewest number of mismatch relationships in the setpoints is obtained. Again, taking the grounding distance protection stage II as an example, the operating time of stage II... When setting the time, it is necessary to coordinate with adjacent protection according to the stepped characteristics, and the value is generally taken between 0.5 and 2.0 seconds. When coordinating with the adjacent next-level protection distance I segment, take... =0.8; when coordinating with the adjacent next-level protection distance II segment, take Here, we take the grade difference. The value is 0.3 seconds; when there is a mismatch between the set value and the adjacent next-level protection, the action time is considered to match with its second stage, which is called incomplete matching, and the value is still taken as 0.3 seconds. , The operating time is 0.3 seconds. When a protection system needs to be coordinated with multiple adjacent downstream protection systems, the operating time of the protection's Stage II protection is [not specified]. Take the maximum value among the various time-matching values.

[0194] The specific action timing tuning strategy is as follows:

[0195] (1) Construct the protection association matrix RIM, find the cooperation relationships that are not in the loop, and remove them.

[0196] (2) If RIM is not empty after removal, it means that there is a coherent segment. At this time, the remaining elements of RIM are forcibly disconnected according to the decision variable X, which is equivalent to the loop unblocking operation.

[0197] (3) Based on the optimization results, first determine the action time of the protection stage II without coordination relationship. The time coordination value is 0.8 seconds, which corresponds to the protection coordination relationship with segment I on a fixed value. It takes 0.8 seconds.

[0198] (4) Locate the protection for which the time coordination value of each coordination relationship has been calculated, and take the maximum value as the stage II operating time of the protection. And update the calculable protection fit relationship time fit value for stage II fit or misfit at a given value. until no new calculations are available. Until then, protection is achieved.

[0199] (5) For the elements that are forcibly disconnected in RIM according to decision variable X, repeat step (4) because the same segment of the coordination loop is disconnected at this time, so the time coordination value of each coordination relationship can be found.

[0200] (6) Final verification section: For A protection coordination error of more than 2 seconds directly causes a timing mismatch and updates the second-stage action time of each protection system. .

[0201] (7) After the tuning is completed, the operating time of each protection stage II should be verified to obtain the final mismatch in operating time of each protection, and then the decision variables should be updated to calculate the objective function. The adjusted constraint processing procedure is attached. Figure 3 As shown.

[0202] Example 12:

[0203] A setting mismatch optimization method combining relay protection setting principles is described in Example 11. Further, this example takes a 220kV main network in a certain region as an example. The network includes 22 nodes N1~N22 and 43 branches b1~b43, corresponding to 76 protections (excluding protections at traction substations). Based on the amplification factor and topology, a total of 291 protection coordination relationships need to be considered.

[0204] Table 1 Mismatch in the Setting Results of Power Grid Section II

[0205]

[0206] Taking the setting of the second stage of grounding distance protection as an example, the reliability coefficient of the second stage is taken. The sensitivity coefficient for segment II is 0.7. Routes under 50km =1.45, for routes between 50km and 100km =1.4, for routes of 100km~150km =1.35, for routes of 150km~200km =1.3, for lines over 200 kilometers =1.25; Amplification factor Based on the process of obtaining power grid fault preparedness, the smaller of the minimum positive sequence boosting coefficient and the minimum zero sequence boosting coefficient under various operating modes is selected.

[0207] The genetic algorithm was used to solve the tuning optimization model. The population size was set to 2000, the maximum number of iterations was set to 2000, the crossover rate was set to 0.8, and the mutation rate was set to 0.2.

[0208] Verification revealed that the optimized setting results for Stage II resulted in 23 protection coordination mismatches in setting values ​​and 13 in operating time, with two mismatches in both setting values ​​and operating time. In contrast, the actual power grid setting results showed 55 protection coordination mismatches in setting values ​​and 46 in operating time, with 13 mismatches in both setting values ​​and operating time. The optimization reduced the number of setting mismatches from 55 to 23 (a 58% reduction) and the number of operating time mismatches from 46 to 13 (a 72% reduction). This invention incorporates the setting process into the constraint handling of the optimization model, determining whether protection coordination is possible and the number of coordination stages through setting calculations. A genetic algorithm is used to solve the model, determining the coordination between protections based on the setting optimization results, and then optimizing the operating time settings. This method allows for the acquisition of optimized tuning results and action times while considering the protection and coordination relationships, thus verifying the effectiveness of the optimization method proposed in this invention.

[0209] Table 2 Mismatch in Section II Tuning and Optimization Results

[0210]

Claims

1. A setting mismatch optimization method combined with the setting principle of relay protection, characterized in that, The method comprises the following steps: 1) obtaining an initial power network structure, and defining a mismatch variable and an auxiliary variable of a protection coordination relationship in the initial power network structure; 2) constructing a setting optimization model based on minimum mismatch relationship importance based on the auxiliary variable; 3) performing constraint processing on the setting optimization model based on minimum mismatch relationship importance based on a relay protection setting principle, to obtain a constraint-processed setting optimization model; 4) solving the constraint-processed setting optimization model based on a genetic algorithm, to obtain an optimized mismatch variable and a setting optimization result; 5) based on the optimized mismatch variable and the setting optimization result, resolving a same-section coordination ring in action time setting through an action time setting optimization method, to generate a final setting optimization scheme.

2. The method of claim 1, wherein the method is based on the principle of setting of the relay protection. The mismatch variable and the auxiliary variable of the protection coordination relationship in the initial power network structure are as follows: （1） （2） In the formula, represents a set of mismatch variables; represents a set of auxiliary variables; , respectively represent the mismatch variable and the auxiliary variable of the th protection coordination relationship, , represents the number of protection coordination relationships; when , it represents that the th protection coordination relationship is mismatched at the setting time; when , it represents that the setting protection and the coordinated protection I section are coordinated in the th protection coordination relationship at the setting time; when , it represents that the setting protection and the coordinated protection II section are coordinated in the th protection coordination relationship at the setting time; when , ; when or , .

3. The method of claim 1, wherein the method is combined with a setting principle of a protective relay, and The objective function of the setting optimization model based on minimum mismatch relationship importance is as follows: （3） In the formula, represents the protection cooperation relationship index; represents the number of protection cooperation relationships; represents the auxiliary variable of the th protection cooperation relationship; represents the importance of the th protection cooperation relationship.

4. The method of claim 1, wherein the method is combined with a setting principle of a protective relay, and The constraint condition of the constraint-processed setting optimization model is that all protection coordination relationships in the mismatch variable pass setting, and the setting values of all protections are calculated; The protection comprises a setting protection, a coordination protection I section, and a coordination protection II section; The constraint processing steps of the setting value of the coordination protection II section are as follows: a1 calculating the setting value of the coordination protection I section, the sensitivity requirement value of the coordination protection II section, and the coordination value of the setting protection and the coordination protection I section in the protection coordination relationship according to power network parameters and setting coefficients, as follows: （4） （5） （6） In the formula, represents the coordination protection I segment value; represents the coordination protection II segment sensitivity requirement value; represents the coordination protection I segment value in the protection coordination relationship; represents the coordination protection I segment reliability coefficient; represents the line positive sequence impedance; represents the coordination protection II segment sensitivity coefficient; represents the coordination protection II segment reliability coefficient; represents the auxiliary increase coefficient; a2 finding the protection coordination relationship cooperating with the coordination protection I section based on the setting value of the coordination protection I section, the sensitivity requirement value of the coordination protection II section, and the coordination value of the setting protection and the coordination protection I section in the protection coordination relationship, to form a protection coordination relationship set RDRII_I; The setting protection cooperates with the protection I section cooperation value Not less than the sensitivity of the protection II section value ; a3 judging whether there is a protection coordination relationship with a mismatch variable of 2 in the protection coordination relationship set RDRII_I, if yes, entering step a4, and if no, entering step a5; a4 calculates the sensitivity requirement value of the setting protection and the coordinated protection II section in the protection coordination relationship set RDRII_I with all mismatch variables of 2, as the coordination value of the setting protection and the coordinated protection II section in the protection coordination relationship and enters step a5; a5 judging whether there is a protection coordination relationship with a mismatch variable of 1, if yes, entering step a6, and if no, entering step a9; a6 judging whether there is a protection coordination relationship with a mismatch variable of 1 in the protection coordination relationship set RDRII_I, if yes, entering step a7, and if no, entering step a8; a7 let the protection coordination relationship set RDRII_I all mismatch variables to 1 of the protection coordination relationship by setting the protection and coordination I segment coordination value coordinated setting, and enter step a9; a8 changing the mismatch variable of all protection coordination relationships with a mismatch variable of 1 to 2, and entering step a9; a9 judging whether there is a protection coordination relationship with a mismatch variable of 2, if yes, entering step a10, and if no, entering step a12; a10 determining whether all mismatched variables are set to 2, and if so, entering step a11, and if not, entering step a12 , if so, entering step a11, and if not, entering step a12 a11 setting protection and coordination protection II section coordination value of protection coordination relationship with all mismatch variables being 2 whether the sensitivity requirement is met, if yes, then let protection coordination relationship with all mismatch variables being 2 be according to the setting protection and coordination protection II section coordination value coordinating setting, and entering step a12, if no, then let the mismatch variable of protection coordination relationship not meeting the sensitivity requirement be changed to 0, and enter step a12; a12 finds all the protection fit relationships whose fit protection section number is determined and whose fit value is obtained, selects the minimum value among the fit protection I section fit values obtained by all the iteration numbers as the fit protection I section value in the protection fit relationship and the fit protection II section fit value as the fit protection II section value in the protection fit relationship ; a13 determining the value of the fit protection ii segment whether a difference has occurred from the previous iteration, and if so, returning to step a9, and if not, proceeding to step a14 a14 determine if there is a coordinated protection II segment value unregulated protection, if yes, go to step a15, if no, go to step a16; a15 set the value of the protection II segment The mismatch variable of the unadjusted protection fit relationship is changed to 0; a16 obtaining the setting value of all coordination protection II sections and the corresponding mismatch variable.

5. The method of claim 4, wherein the method is combined with a setting principle of a protective relay, and The sensitivity requirement value of the setting protection and the coordination protection II section in the protection coordination relationship is as follows: （7） In the formula, represents the sensitivity requirement value of the setting protection and the coordinated protection II section in the protection coordination relationship; represents the sensitivity requirement value of the coordinated protection II section; represents the positive sequence impedance of the line; represents the reliability coefficient of the coordinated protection II section; represents the auxiliary increase coefficient.

6. The method of claim 4, wherein the method is characterized by, The sensitivity requirement is as follows: （8） In the formula, represents the sensitivity requirement value of the coordinated protection II section; represents the coordinated value of the coordinated protection I section in the protection coordination relationship; represents the sensitivity requirement value of the coordinated protection II section in the protection coordination relationship; represents the coordinated value of the coordinated protection II section in the protection coordination relationship.

7. The method of claim 1, wherein the method is combined with a setting principle of a protective relay, and In step 4), the steps of obtaining the optimized mismatch variable and the setting optimization result are as follows: b1 forming an adaptive function based on the constraint-processed setting optimization model; b2 defines a set of mismatch variables for individual, initialize population and number of iterations; b3 calculating the fitness of each individual in the population, and updating to obtain an optimal fitness individual; b4 forming a new generation population through selection, crossover, and mutation; b5 judge whether the maximum iteration number is reached, if not, then let the iteration number plus one, and return to step b3; if yes, then enter step b6; b6 get the optimized mismatch variable and the fixed value optimization result.

8. The method of claim 1, wherein the method is combined with a setting principle of a protective relay, and In step 5), the steps of generating the final setting optimization scheme are as follows: c1 based on the optimized mismatch variable, construct the protection association matrix RIM; The rows and columns of the protection incidence matrix RIM represent protections in the initial power network structure, the elements represent the cooperation of the s-th protection with the t-th protection, when represent the non-cooperation of the s-th protection with the t-th protection, when represent the cooperation of the s-th protection with the t-th protection; c2 removing elements in the protection association matrix RIM the row of all 0s and the column of all 0s, to obtain an updated protection association matrix RIM; c3determining whether there is an element in the updated protection correlation matrix RIM a row of all 0s or a column of all 0s, if yes, then the updated protection correlation matrix RIM returns to step c2, if no, then step c4 is entered; c4 judge whether the updated protection association matrix RIM is empty set, if yes, then enter step c6, if not, then enter step c5; c5 let the remaining elements in the updated protection incidence matrix RIM The corresponding protection coordination relationship is directly disconnected, and the corresponding mismatch variable is updated to 1, and step c6 is entered; c6 through the action time setting optimization method, break the same section cooperation ring in the action time setting, and generate the final setting optimization scheme.

9. The method of claim 8, wherein the method is combined with a setting principle of a protective relay, and In step c6, the steps of breaking the same section cooperation ring in the action time setting through the action time setting optimization method are as follows: c61 according to the updated mismatch variable, eliminate the mismatched protection cooperation relationship; c62 determine the action time of the protection cooperation II section without cooperation relationship protection based on the fixed value optimization result , the protection cooperation relationship time cooperation value cooperating with the protection cooperation I section ; c63 for the protection of the time coordination value of the existing protection coordination relationship, select the maximum value as the coordination protection II segment action time of the protection , and update the time coordination value of the protection coordination relationship that is in coordination or mismatch with the coordination protection II segment ; c64 determine whether all protected matching protected II segment action times are obtained If not, return to step c63, and if yes, proceed to step c65. c65 protection coordination relationship time coordination value The protection coordination relationship greater than the preset value is mismatched in time, and each protection is updated with a coordination protection II segment action time ; c66 get the action time of each protection after the coordination of the protection II section and the mismatch variable of each protection on the action time, generate the final optimization scheme of setting.

10. The method of claim 9, wherein the method is combined with a setting principle of a protective relay, and The time of the protection cooperation relationship with the cooperation or mismatch of the cooperation protection II section The update formula is as follows: （9） In the formula, represents the time level difference, represents the maximum value among all the cooperative protection action times.

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