Reliability evaluation method and system for complex radial distribution network based on network equivalence

Abstract

A reliability evaluation method for complex radial distribution network based on network equivalence is proposed. First, the reliability equivalent network of the complex radial distribution network is established, then the load type matrix is ​​constructed, and then it is determined whether there is a backup power branch. If so, the load type matrix is ​​updated, and finally the final matrix FMRTM is calculated based on the load type matrix. The failure rate and unavailability rate of each load are calculated according to the load type matrix and the final matrix FMRTM. In this design, the concept of reliability network equivalence is introduced, and the reliability index at the load point is mathematically represented in matrix form. The accurate calculation of the load failure rate and unavailability rate is achieved with the help of simple matrix operations. When calculating the matrix, the influence of the upstream protection device of the calculation branch on the failure rate of the load point and the influence of the backup power branch in the distribution network on the equivalent area division are considered, which improves the reliability of the final evaluation result.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid reliability assessment, and in particular relates to a complex radial distribution network reliability assessment method and system based on network equivalence. Background Art

[0002] The distribution system is the last link in delivering electricity to users, and plays a vital role in the reliability of the entire system. About 80% of power outages are caused by distribution system failures. Therefore, the research on the reliability of the distribution system has always attracted much attention. There are two main methods for evaluating system reliability: analytical methods and simulation methods. Although the simulation method has been widely used, its effectiveness depends largely on the number of simulations and is limited by time; the analytical method can determine the exact solution of each load node, but its calculation amount is related to the complexity of the system, and complex radial distribution networks often lead to excessive calculations. In order to reduce the amount of calculation, an equivalent unit is used to replace part of the distribution network, and finally a large complex radial distribution network is reduced to a smaller equivalent network, which is used for distribution network reliability assessment. However, in the traditional matrix calculation, the influence of the upstream protection device of the calculation branch on the load point failure rate and the influence of the backup power branch in the distribution network on the equivalent area division are not considered, and there is a problem of poor reliability of the final evaluation result. Summary of the invention

[0003] The purpose of the present invention is to provide a complex radial distribution network reliability assessment method and system based on network equivalence, which can improve the reliability of the assessment result, in view of the above problems existing in the prior art.

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

[0005] In a first aspect, the present invention provides a complex radial distribution network reliability assessment method based on network equivalence, the assessment method comprising the following steps:

[0006] S1. Establish a reliability equivalent network of a complex radial distribution network and obtain the failure rate, fault recovery time, and protection device operation failure probability of each branch in the complex radial distribution network;

[0007] S2. Based on the complex radial distribution network, a busbar-to-branch current injection matrix BIBC is constructed. The 0 elements in each row of the busbar-to-branch current injection matrix BIBC are replaced with the operation failure probability of the protection device of the branch corresponding to the row. If the branch corresponding to the row has a protection device, its operation failure probability is 0. If it does not have a protection device, its operation failure probability is 1, so as to construct a failure mode and influence coefficient matrix FMECM; each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source to obtain a load type matrix LTM;

[0008] S3, determine whether there is a backup power supply branch in the complex radial distribution network, if not, proceed to step S4, if yes, proceed to step S5;

[0009] S4. Replace the 0 elements in each row of the load type matrix LTM with the switch time of the protection device of the branch corresponding to the row, and replace the 1 elements in each row with the fault recovery time of the branch corresponding to the row, and obtain the initial fault mode and interruption time matrix FMITM initial ; The initial failure mode and interruption time matrix FMITM initial Perform element-by-element multiplication with the load type matrix LTM to obtain the final matrix FMRTM; proceed to step S7;

[0010] S5. Construct the regional branch injection current matrix ZBCBI based on the reliability equivalent network, replace the 0 elements in each row of the regional branch injection current matrix ZBCBI with the operation failure probability of the protection device of the branch corresponding to the row. If the branch corresponding to the row has a protection device, the operation failure probability is set to 0; if there is no protection device, the operation failure probability is set to 1, so as to construct the failure mode and influence coefficient matrix FMECM; multiply each element in the failure mode and influence coefficient matrix FMECM by the path element from the branch to the source to obtain the isolation load matrix ILM; obtain the updated load type matrix LTM according to the following formula alt ;

[0011] Updated load type matrix LTM alt = load type matrix LTM + isolation load matrix ILM;

[0012] S6. Update the load type matrix LTM alt The 0 element in each row is replaced by the switch time of the protection device of the branch corresponding to the row, the 1 element in each row is replaced by the sum of the time required to turn off the backup power switch and the switch time of the protection device of the branch corresponding to the row, and the 2 element in each row is replaced by the fault recovery time of the branch corresponding to the row, and the initial fault mode and interruption time matrix FMITM is obtained. initial ; The initial failure mode and interruption time matrix FMITM initial With the updated load type matrix LTM alt Perform element-by-element multiplication to obtain the final matrix FMRTM; proceed to step S7;

[0013] S7. Calculate the failure rate of each load according to the load type matrix LTM and the failure rate of each branch; calculate the unavailability rate of each load according to the final matrix FMRTM and the failure rate of each branch.

[0014] The failure rate and unavailability rate of each load are calculated according to the following formula:

[0015]

[0016]

[0017] In the above formula, λ Load-1 , Load-n are the failure rates of the first and nth loads respectively; U Load-1 , U Load-n are the unavailability rates of the first and nth loads respectively; Branch-1 , Branch-n are the failure rates of the first and nth branches respectively; FMRTM T is the transpose of the final matrix FMRTM; LTM T is the transpose of the load type matrix LTM.

[0018] The protection device includes a circuit breaker, a fuse and an isolating switch.

[0019] The busbar to branch current injection matrix BIBC and the regional branch injection current matrix ZBCBI are both obtained by writing branch current equations according to Kirchhoff's current law.

[0020] In a second aspect, the present invention provides a complex radial distribution network reliability assessment system based on network equivalence, the assessment system comprising a reliability equivalent network establishment module, a load type matrix construction module, a backup power branch judgment module, a load type matrix update module, a final matrix construction module, and a reliability assessment module;

[0021] The reliability equivalent network establishment module is used to establish a reliability equivalent network of a complex radial distribution network and obtain the failure rate, fault recovery time, and protection device operation failure probability of each branch in the complex radial distribution network;

[0022] The load type matrix construction module is used to first construct a bus-to-branch current injection matrix BIBC based on a complex radial distribution network, replace the 0 elements in each row of the bus-to-branch current injection matrix BIBC with the protection device operation failure probability of the branch corresponding to the row, if the branch corresponding to the row is equipped with a protection device, then its operation failure probability is 0, if not equipped with a protection device, then its operation failure probability is 1, so as to construct a failure mode and influence coefficient matrix FMECM; multiply each element in the failure mode and influence coefficient matrix FMECM by the path element from the branch to the source, so as to obtain a load type matrix LTM;

[0023] The backup power branch judgment module is used to judge whether there is a backup power branch in the complex radial distribution network;

[0024] The load type matrix update module is used to first construct a regional branch injection current matrix ZBCBI based on a reliability equivalent network, replace the 0 elements in each row of the regional branch injection current matrix ZBCBI with the protection device operation failure probability of the branch corresponding to the row, if the branch corresponding to the row is equipped with a protection device, the operation failure probability is set to 0, if not equipped with a protection device, the operation failure probability is set to 1, so as to construct a failure mode and influence coefficient matrix FMECM; multiply each element in the failure mode and influence coefficient matrix FMECM by the path element from the branch to the source to obtain an isolation load matrix ILM; obtain an updated load type matrix LTM according to the following formula alt ;

[0025] Updated load type matrix LTM alt = load type matrix LTM + isolation load matrix ILM;

[0026] The final matrix building module is used to replace the 0 elements in each row of the load type matrix LTM with the switching time of the protection device of the branch corresponding to the row, and replace the 1 elements in each row with the fault recovery time of the branch corresponding to the row when there is no backup power branch, so as to obtain the initial fault mode and interruption time matrix FMITM initial ; The initial failure mode and interruption time matrix FMITM initial The updated load type matrix LTM is multiplied element by element with the load type matrix LTM to obtain the final matrix FMRTM. alt The 0 element in each row is replaced by the switch time of the protection device of the branch corresponding to the row, the 1 element in each row is replaced by the sum of the time required to turn off the backup power switch and the switch time of the protection device of the branch corresponding to the row, and the 2 element in each row is replaced by the fault recovery time of the branch corresponding to the row, and the initial fault mode and interruption time matrix FMITM is obtained. initial ; The initial failure mode and interruption time matrix FMITM initial With the updated load type matrix LTM alt Perform element-by-element multiplication to obtain the final matrix FMRTM;

[0027] The reliability evaluation module is used to calculate the failure rate of each load according to the load type matrix LTM and the failure rate of each branch, and calculate the unavailability rate of each load according to the final matrix FMRTM and the failure rate of each branch.

[0028] The reliability evaluation module calculates the failure rate and unavailability rate of each load according to the following formula:

[0029]

[0030]

[0031] In the above formula, λ Load-1 , Load-n are the failure rates of the first and nth loads respectively; U Load-1 , U Load-n are the unavailability rates of the first and nth loads respectively; Branch-1 , Branch-n are the failure rates of the first and nth branches respectively; FMRTM T is the transpose of the final matrix FMRTM; LTM T is the transpose of the load type matrix LTM.

[0032] The protection device includes a circuit breaker, a fuse and an isolating switch.

[0033] The busbar to branch current injection matrix BIBC and the regional branch injection current matrix ZBCBI are obtained by writing branch current equations according to Kirchhoff's current law.

[0034] In a third aspect, the present invention provides a complex radial distribution network reliability assessment device based on network equivalence, the assessment device comprising a memory and a processor;

[0035] The memory is used to store computer program code and transmit the computer program code to the processor;

[0036] The processor is used to execute the aforementioned method according to the instructions in the computer program code.

[0037] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the aforementioned method when executed by a processor.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention introduces the concept of reliability network equivalence to a complex radial distribution network reliability assessment method based on network equivalence, realizes the equivalence of complex radial distribution networks, and then mathematically characterizes the reliability index at the load point in the form of a matrix, and accurately calculates the load failure rate and unavailability rate of the distribution network with the help of simple matrix operations; when calculating the matrix, the influence of the upstream protection device of the calculation branch on the load point failure rate and the influence of the backup power supply branch in the distribution network on the equivalent area division are considered, thereby improving the reliability of the final assessment result. Therefore, the reliability of the final assessment result of the present invention is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention is a flowchart of the evaluation method.

[0041] Figure 2 The network structure is a 7-bus radial distribution network.

[0042] Figure 3 The reliability equivalent network of the 7-bus radial distribution network.

[0043] Figure 4 It is a schematic diagram of the structure of the evaluation system of the present invention.

[0044] Figure 5 It is a schematic diagram of the structure of the evaluation device of the present invention. DETAILED DESCRIPTION

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

[0046] Embodiment 1:

[0047] This embodiment is as follows Figure 2 The 7-bus radial distribution network shown in FIG. 1 is used as an example for explanation. The protection devices in the 7-bus radial distribution network include 3 circuit breakers, 2 fuses and 1 disconnector; see Figure 1 , a reliability assessment method for complex radial distribution networks based on network equivalence is specifically carried out in the following steps:

[0048] 1. The 7-bus radial distribution network is separated by the protection device to form six relatively independent protection areas, as shown below: Figure 3 In the reliability equivalent network shown, branches 2 and 3 are both located in protection area 2; the failure rate and recovery time of each branch are obtained;

[0049] 2. Construct network data matrix ND:

[0050]

[0051] In the network data matrix ND, the columns from left to right represent the 1st to 7th branches respectively, and the first to last rows in each column represent the outgoing bus, access bus, protection device information, and operation failure probability corresponding to the protection device of the branch respectively; for the protection device information, 0 means no protection device, 1 means circuit breaker, 2 means fuse, and 3 means disconnect switch;

[0052] 3. For example Figure 2 The 7-bus radial distribution network shown is written as the following current equations according to Kirchhoff's current law:

[0053] I1=B1-B2;

[0054] I2=B2-B3-B5;

[0055] I3=B3-B4;

[0056] I4=B4;

[0057] I5=B5-B6;

[0058] I6=B6-B7;

[0059] I7=B7;

[0060] In the above formula, I i is the equivalent current injected into busbar i, B i is the current injected into branch i;

[0061] The coefficient matrix of the above current equations is the branch injection bus current matrix BCBI:

[0062]

[0063] Then, the busbar to branch current injection matrix BIBC is constructed according to the branch injection bus current matrix BCBI:

[0064]

[0065] Replace the 0 elements in each row of the busbar to branch current injection matrix BIBC with the failure probability of the protection device operation of the corresponding branch in this row, and obtain the failure mode and influence coefficient matrix FMECM:

[0066]

[0067] Considering the influence of the upstream network protection device on the failure rate of the downstream network load point, each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source (for example, multiply 1, q2, q5, q6, q7 in the failure mode and influence coefficient matrix FMECM to obtain the element in the seventh row and first column of the load type matrix LTM, and multiply 1, 1, q3, q4 in the failure mode and influence coefficient matrix FMECM to obtain the element in the fourth row and seventh column of the load type matrix LTM), and the following matrix is ​​obtained:

[0068]

[0069] To simplify the matrix calculation, the operation failure probability with protection devices in the network data matrix ND is set to 0, and the operation failure probability without protection devices is set to 1, and the following load type matrix LTM is obtained:

[0070]

[0071] 4. Determine whether there is a backup power supply branch in the complex radial distribution network. If not, proceed to step 5. If so, proceed to step 6.

[0072] 5. Replace the 0 element in each row of the load type matrix LTM with the switch time of the protection device of the corresponding branch in the row, and replace the 1 element in each row with the fault recovery time of the corresponding branch in the row, and obtain the initial fault mode and interruption time matrix FMITM initial ; The initial failure mode and interruption time matrix FMITM initial Perform element-by-element multiplication with the load type matrix LTM to obtain the final matrix FMRTM; proceed to step 8;

[0073] 6. For Figure 3 The reliability equivalent network shown is written as the following current equations according to Kirchhoff's current law:

[0074] I1=B1;

[0075] I2=B2-B3;

[0076] I3=B3;

[0077] I4=B4;

[0078] I5=B5;

[0079] I6=B6;

[0080] I7=B7;

[0081] Then, the regional branch injection current matrix ZBCBI is constructed according to the above current equations:

[0082]

[0083] Replace the 0 elements in each row of the regional branch injection current matrix ZBCBI with the failure probability of the protection device operation of the corresponding branch in the row, and construct the failure mode and influence coefficient matrix FMECM:

[0084]

[0085] Considering the impact of upstream network protection devices on the failure rate of downstream network load points, each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source, and the following matrix is ​​obtained:

[0086]

[0087] To simplify the matrix calculation, the operation failure probability with protection devices in the network data matrix ND is set to 0, and the operation failure probability without protection devices is set to 1, and the isolation load matrix ILM is obtained:

[0088]

[0089] The updated load type matrix LTM is obtained according to the following formula alt ;

[0090] Updated load type matrix LTM alt = load type matrix LTM + isolation load matrix ILM;

[0091] Get the updated load type matrix LTM alt for:

[0092]

[0093] 7. Update the load type matrix LTM alt The 0 element in each row is replaced by the switch time of the protection device of the branch corresponding to the row, the 1 element in each row is replaced by the sum of the time required to turn off the backup power switch and the switch time of the protection device of the branch corresponding to the row, and the 2 element in each row is replaced by the fault recovery time of the branch corresponding to the row, and the initial fault mode and interruption time matrix FMITM is obtained. initial ; The initial failure mode and interruption time matrix FMITM initial With the updated load type matrix LTM alt Perform element-by-element multiplication to obtain the final matrix FMRTM; proceed to step 8;

[0094] 8. Calculate the failure rate and unavailability rate of each load according to the following formula:

[0095]

[0096]

[0097] In the above formula, λ Load-1 , Load-n are the failure rates of the first and nth loads respectively; U Load-1 , U Load-n are the unavailability rates of the first and nth loads respectively; Branch-1 , Branch-n are the failure rates of the first and nth branches respectively; FMRTM T is the transpose of the final matrix FMRTM; LTM T is the transpose of the load type matrix LTM.

[0098] Embodiment 2:

[0099] See also Figure 4 , a complex radial distribution network reliability assessment system based on network equivalence, including a reliability equivalent network establishment module, a load type matrix construction module, a backup power branch judgment module, a load type matrix update module, a final matrix construction module, and a reliability assessment module;

[0100] The reliability equivalent network establishment module is used to establish a reliability equivalent network of a complex radial distribution network and obtain the failure rate, fault recovery time, and protection device operation failure probability of each branch in the complex radial distribution network;

[0101] The load type matrix construction module is used to first write the branch current equation based on the complex radial distribution network according to Kirchhoff's current law, construct the busbar to branch current injection matrix BIBC, replace the 0 elements in each row of the busbar to branch current injection matrix BIBC with the protection device operation failure probability of the branch corresponding to the row, if the branch corresponding to the row is equipped with a protection device, then its operation failure probability is 0, if not equipped with a protection device, then its operation failure probability is 1, so as to construct a failure mode and influence coefficient matrix FMECM; each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source, so as to obtain the load type matrix LTM;

[0102] The backup power branch judgment module is used to judge whether there is a backup power branch in the complex radial distribution network;

[0103] The load type matrix update module is used to first write the branch current equation based on the reliability equivalent network according to Kirchhoff's current law, construct the regional branch injection current matrix ZBCBI, replace the 0 elements in each row of the regional branch injection current matrix ZBCBI with the operation failure probability of the protection device of the branch corresponding to the row, if the branch corresponding to the row is equipped with a protection device, the operation failure probability is set to 0, if not equipped with a protection device, the operation failure probability is set to 1, so as to construct a failure mode and influence coefficient matrix FMECM; multiply each element in the failure mode and influence coefficient matrix FMECM by the path element from the branch to the source to obtain the isolation load matrix ILM; obtain the updated load type matrix LTM according to the following formula alt ;

[0104] Updated load type matrix LTM alt = load type matrix LTM + isolation load matrix ILM;

[0105] The final matrix building module is used to replace the 0 elements in each row of the load type matrix LTM with the switching time of the protection device of the branch corresponding to the row, and replace the 1 elements in each row with the fault recovery time of the branch corresponding to the row when there is no backup power branch, so as to obtain the initial fault mode and interruption time matrix FMITM initial ; The initial failure mode and interruption time matrix FMITM initial The updated load type matrix LTM is multiplied element by element with the load type matrix LTM to obtain the final matrix FMRTM.alt The 0 element in each row is replaced by the switch time of the protection device of the branch corresponding to the row, the 1 element in each row is replaced by the sum of the time required to turn off the backup power switch and the switch time of the protection device of the branch corresponding to the row, and the 2 element in each row is replaced by the fault recovery time of the branch corresponding to the row, and the initial fault mode and interruption time matrix FMITM is obtained. initial ; The initial failure mode and interruption time matrix FMITM initial With the updated load type matrix LTM alt Perform element-by-element multiplication to obtain the final matrix FMRTM;

[0106] The reliability evaluation module is used to calculate the failure rate and unavailability rate of each load according to the following formula:

[0107]

[0108]

[0109] In the above formula, λ Load-1 , Load-n are the failure rates of the first and nth loads respectively; U Load-1 , U Load-n are the unavailability rates of the first and nth loads respectively; Branch-1 , Branch-n are the failure rates of the first and nth branches respectively; FMRTM T is the transpose of the final failure mode and interruption time matrix FMITM; LTM T is the transpose of the load type matrix LTM.

[0110] Embodiment 3:

[0111] refer to Figure 5 , a complex radial distribution network reliability assessment device based on network equivalence, comprising a memory and a processor; the memory is used to store computer program code and transmit the computer program code to the processor; the processor is used to execute the method described in Example 1 according to the instructions in the computer program code.

[0112] Embodiment 4:

[0113] A computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the method described in Example 1 when executed by a processor.

[0114] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0115] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0116] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0117] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0118] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A complex radial distribution network reliability assessment method based on network equivalence, characterized by: The evaluation method comprises the following steps: S1. Establish a reliability equivalent network of a complex radial distribution network and obtain the failure rate, fault recovery time, and protection device operation failure probability of each branch in the complex radial distribution network; S2. Based on the complex radial distribution network, a busbar-to-branch current injection matrix BIBC is constructed. The 0 elements in each row of the busbar-to-branch current injection matrix BIBC are replaced with the operation failure probability of the protection device of the branch corresponding to the row. If the branch corresponding to the row has a protection device, its operation failure probability is 0. If it does not have a protection device, its operation failure probability is 1, so as to construct a failure mode and influence coefficient matrix FMECM; each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source to obtain a load type matrix LTM; S3, determine whether there is a backup power supply branch in the complex radial distribution network, if not, proceed to step S4, if yes, proceed to step S5; S4. Replace the 0 elements in each row of the load type matrix LTM with the switch time of the protection device of the branch corresponding to the row, and replace the 1 elements in each row with the fault recovery time of the branch corresponding to the row, and obtain the initial fault mode and interruption time matrix FMITM initial ; The initial failure mode and interruption time matrix FMITM initial Perform element-by-element multiplication with the load type matrix LTM to obtain the final matrix FMRTM; proceed to step S7; S5. Construct the regional branch injection current matrix ZBCBI based on the reliability equivalent network, replace the 0 elements in each row of the regional branch injection current matrix ZBCBI with the operation failure probability of the protection device of the branch corresponding to the row. If the branch corresponding to the row has a protection device, the operation failure probability is set to 0; if there is no protection device, the operation failure probability is set to 1, so as to construct the failure mode and influence coefficient matrix FMECM; multiply each element in the failure mode and influence coefficient matrix PFECM by the path element from the branch to the source to obtain the isolation load matrix ILM; obtain the updated load type matrix LTM according to the following formula alt ; Updated load type matrix LTM alt = load type matrix LTM + isolation load matrix ILM; S6. Update the load type matrix ITM alt The 0 element in each row is replaced by the switch time of the protection device of the branch corresponding to the row, the 1 element in each row is replaced by the sum of the time required to turn off the backup power switch and the switch time of the protection device of the branch corresponding to the row, and the 2 element in each row is replaced by the fault recovery time of the branch corresponding to the row, and the initial fault mode and interruption time matrix FMITM is obtained. initial ; The initial failure mode and interruption time matrix FMITM initial With the updated load type matrix LTM alt Perform element-by-element multiplication to obtain the final matrix FMRTM; proceed to step S7; S7, calculating the failure rate of each load according to the load type matrix LTM and the failure rate of each branch; calculating the unavailability rate of each load according to the final matrix FMRTM and the failure rate of each branch; The failure rate and unavailability rate of each load are calculated according to the following formula: In the above formula, λ Load-1 , Load-n are the failure rates of the first and nth loads respectively; U Load-1 , U Load-n are the unavailability rates of the first and nth loads respectively; Branch-1 , Branch-n are the failure rates of the first and nth branches respectively; FMRTM T is the transpose of the final matrix FMRTM; LTM T is the transpose of the load type matrix LTM.

2. The complex radial distribution network reliability assessment method based on network equivalence according to claim 1 is characterized in that: The protection device includes a circuit breaker, a fuse and an isolating switch.

3. The complex radial distribution network reliability assessment method based on network equivalence according to claim 1 is characterized in that: The busbar to branch current injection matrix BIBC and the regional branch current injection matrix ZBIBC are both obtained by writing branch current equations according to Kirchhoff's current law.

4. A complex radial distribution network reliability assessment system based on network equivalence, characterized by: The evaluation system includes a reliability equivalent network establishment module, a load type matrix construction module, a backup power branch judgment module, a load type matrix update module, a final matrix construction module, and a reliability evaluation module; The reliability equivalent network establishment module is used to establish a reliability equivalent network of a complex radial distribution network and obtain the failure rate, fault recovery time, and protection device operation failure probability of each branch in the complex radial distribution network; The load type matrix construction module is used to first construct a bus-to-branch current injection matrix BIBC based on a complex radial distribution network, and replace the 0 elements in each row of the bus-to-branch current injection matrix BIBC with the operation failure probability of the protection device of the branch corresponding to the row. If the branch corresponding to the row is equipped with a protection device, its operation failure probability is 0, and if it is not equipped with a protection device, its operation failure probability is 1, so as to construct a failure mode and influence coefficient matrix FMECM; Each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source to obtain the load type matrix LTM; The backup power branch judgment module is used to judge whether there is a backup power branch in the complex radial distribution network; The load type matrix update module is used to first construct a regional branch injection current matrix ZBIBC based on the reliability equivalent network, and replace the 0 elements in each row of the regional branch injection current matrix ZBCBI8 with the operation failure probability of the protection device of the branch corresponding to the row. If the branch corresponding to the row is equipped with a protection device, the operation failure probability is set to 0; if it is not equipped with a protection device, the operation failure probability is set to 1, so as to construct a failure mode and influence coefficient matrix FMECM; Each element in the failure mode and influence coefficient matrix FMECM is multiplied by the path element from the branch to the source to obtain the isolation load matrix ILM; The updated load type matrix LTM is obtained according to the following formula alt ; Updated load type matrix LTM alt = load type matrix LTM + isolation load matrix ILM; The final matrix building module is used to replace the 0 elements in each row of the load type matrix LTM with the switching time of the protection device of the branch corresponding to the row, and replace the 1 elements in each row with the fault recovery time of the branch corresponding to the row when there is no backup power branch, so as to obtain the initial fault mode and interruption time matrix FMITM initial ; The initial failure mode and interruption time matrix FMITM initial The updated load type matrix LTM is multiplied element by element with the load type matrix LTM to obtain the final matrix FMRTM. alt The 0 element in each row is replaced by the switch time of the protection device of the branch corresponding to the row, the 1 element in each row is replaced by the sum of the time required to turn off the backup power switch and the switch time of the protection device of the branch corresponding to the row, and the 2 element in each row is replaced by the fault recovery time of the branch corresponding to the row, and the initial fault mode and interruption time matrix FMITM is obtained. initial ; The initial failure mode and interruption time matrix FMITM initial With the updated load type matrix LTM alt Perform element-by-element multiplication to obtain the final matrix FMRTM; The reliability evaluation module is used to calculate the failure rate of each load according to the load type matrix LTM and the failure rate of each branch, and calculate the unavailability rate of each load according to the final matrix FMRTM and the failure rate of each branch; The reliability evaluation module calculates the failure rate and unavailability rate of each load according to the following formula: In the above formula, λ Load-1 , Load-n are the failure rates of the first and nth loads respectively; U Load-1 , U Load-n are the unavailability rates of the first and nth loads respectively; Branch-1 , Branch-n are the failure rates of the first and nth branches respectively; FMRTM T is the transpose of the final matrix FMRTM; LTM T is the transpose of the load type matrix LTM.

5. The complex radial distribution network reliability assessment system based on network equivalence according to claim 4 is characterized in that: The protection device includes a circuit breaker, a fuse and an isolating switch.

6. The complex radial distribution network reliability assessment system based on network equivalence according to claim 4 is characterized in that: The busbar to branch current injection matrix BIBC and the regional branch injection current matrix ZBCBI are both obtained by writing branch current equations according to Kirchhoff's current law.

7. A complex radial distribution network reliability assessment device based on network equivalence, characterized by: The evaluation device includes a memory and a processor; The memory is used to store computer program code and transmit the computer program code to the processor; The processor is configured to execute the method according to any one of claims 1 to 3 according to instructions in the computer program code.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 3 is implemented.

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