Power system state enumeration reliability evaluation method, system, equipment and medium

Abstract

The invention discloses a power system state enumeration reliability evaluation method, system and device and a medium, and relates to the technical field of power system reliability evaluation and analysis, and the method comprises the steps: constructing a reliability index calculation function based on an influence increment state enumeration method; according to the reliability index calculation function, dividing the reliability index into each order component; calculating to obtain a first-order component and a second-order component of the reliability index, and taking the sum of the two components as a reliability index reference result; constructing an upper and lower bound iterative calculation sequence based on the reliability index reference result; taking a target function that the distance absolute value of the upper and lower bound iterative calculation sequence is smaller than an allowable error, and iteratively calculating upper and lower bound evaluation results; and if the upper and lower bound evaluation results meet the evaluation precision, outputting the evaluation result, otherwise, adjusting the convergence parameter, continuing the iterative calculation until the convergence condition and the evaluation precision are met, and outputting the result. The reliability of the power system can be quickly and accurately calculated and evaluated, and the calculation and evaluation efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power system reliability assessment and analysis, and in particular to a power system state enumeration reliability assessment method, system, equipment and medium. Background Art

[0002] Power system reliability assessment is of vital importance in modern power systems. Its main purpose is to evaluate whether the power system can continuously and reliably provide electricity to users by analyzing its performance under different working conditions and operating conditions. The results of reliability assessment help to identify potential system weaknesses and provide a basis for decision-making in grid planning, operation optimization, fault prevention, and equipment investment.

[0003] In the reliability assessment of power systems, one of the commonly used methods is the enumeration method, which evaluates the reliability of the system by listing all possible system states. However, with the expansion of the scale of power systems, the complexity and computational complexity of enumerating all states are growing exponentially, so the traditional enumeration evaluation algorithm faces efficiency problems. Therefore, it is urgent to study a new reliability evaluation algorithm to obtain clear evaluation results in a shorter time, and then make timely and accurate decisions to ensure the stability and safe operation of the power grid. Summary of the invention

[0004] In order to solve the problem of low evaluation efficiency of traditional enumeration evaluation algorithms, this application proposes a power system state enumeration reliability evaluation method, system, equipment and medium, which adopts a reliability evaluation algorithm based on boundary iterative improvement calculation, which can quickly and accurately realize the calculation and evaluation of power system reliability and improve the calculation and evaluation efficiency.

[0005] In the first aspect, the present application is implemented through the following technical solutions:

[0006] A method for evaluating the reliability of power system state enumeration, the method comprising:

[0007] Based on the impact increment state enumeration method, a reliability index calculation function is constructed;

[0008] According to the reliability index calculation function, the reliability index is divided into components of various orders;

[0009] The first-order component and the second-order component of the reliability index are calculated, and the sum of the first-order component and the second-order component of the reliability index is used as a reliability index benchmark result;

[0010] According to preset conditions, constructing an upper and lower bound iterative calculation sequence based on the reliability index benchmark results;

[0011] The upper and lower bounds are evaluated by iteratively calculating the absolute value of the distance between the upper and lower bounds and the allowable error as the objective function; the allowable error is the ratio of the reliability index benchmark result to the convergence parameter;

[0012] If the upper and lower bound evaluation results under the given convergence parameters obtained by iterative calculation meet the evaluation accuracy, the evaluation results are output; otherwise, the convergence parameters are adjusted to continue the iterative calculation until the convergence conditions and evaluation accuracy are met and the results are output.

[0013] In some embodiments, the evaluation method further comprises:

[0014] Based on the output power system reliability assessment results, the key lines that cause reduced system reliability are analyzed and reinforced, ultimately achieving improved overall system reliability after line reinforcement.

[0015] In some implementations, the reliability index calculation function constructed is:

[0016]

[0017] Where n is the enumeration order; s is the enumeration state; M is the total number of transmission lines; is an n-order subset of a set containing M elements; p v is the failure probability of the vth transmission line; is the value of the reliability index at time t; is the reliability index impact increment under the n-th order fault state s at time t.

[0018] In some implementations, the reliability index is divided into various order components according to the reliability index calculation function, which is expressed as:

[0019]

[0020] in, They are the first-order component, second-order component and third-order component of the reliability index respectively.

[0021] In some implementations, constructing an iterative calculation sequence of upper and lower bounds based on the reliability index benchmark results according to preset conditions specifically includes:

[0022] The preset conditions include:

[0023] The upper bound iteration sequence is monotonically decreasing;

[0024] And, the lower bound iteration sequence is monotonically increasing;

[0025] Rearrange the third-order failure probability set in descending order;

[0026] The upper and lower bounds iterative calculation sequence constructed according to the reliability index benchmark results is:

[0027]

[0028] Among them, the upper bound iteration sequence is:

[0029]

[0030] The lower bound iteration sequence is:

[0031]

[0032] in, is the maximum estimated value, is the minimum estimated value, ) is the reliability index benchmark result.

[0033] In some embodiments, the objective function is expressed as:

[0034]

[0035] Among them, δ1 is the allowable error, and k1 is the convergence parameter.

[0036] In a second aspect, the present application proposes a power system state enumeration reliability assessment system, the assessment system comprising:

[0037] An index calculation unit, wherein the index calculation unit constructs a reliability index calculation function based on an impact increment state enumeration method;

[0038] An index dividing unit, wherein the index dividing unit divides the reliability index into components of various orders according to the reliability index calculation function;

[0039] A benchmark calculation unit, wherein the benchmark calculation unit calculates the first-order component and the second-order component of the reliability index, and takes the sum of the first-order component and the second-order component of the reliability index as the reliability index benchmark result;

[0040] A boundary construction unit, wherein the boundary construction unit constructs an upper and lower bound iterative calculation sequence based on the reliability index benchmark result according to preset conditions;

[0041] An iterative calculation unit, wherein the iterative calculation unit takes the absolute value of the distance between the upper and lower bounds iterative calculation series less than the allowable error as the objective function, and iteratively calculates the upper and lower bounds evaluation results; the allowable error is the ratio of the reliability index benchmark result to the convergence parameter;

[0042] And, an output unit, which determines whether the upper and lower bound evaluation results calculated under given convergence parameters meet the evaluation accuracy. If so, the evaluation results are output; otherwise, the convergence parameters are adjusted to continue iterative calculation until the convergence conditions and evaluation accuracy are met and the results are output.

[0043] In some embodiments, the evaluation system further comprises:

[0044] The performance improvement unit analyzes the key circuits that cause the system reliability to decrease according to the output reliability evaluation results, and reinforces the key circuits, thereby finally improving the overall reliability of the system after the circuit reinforcement.

[0045] In a third aspect, the present application proposes a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0046] In a fourth aspect, the present application proposes a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0047] The present application proposes a method, system, device and medium for evaluating the reliability of power system state enumeration, which is based on the impact increment state enumeration method and adopts the boundary iteration improvement algorithm to quickly realize the calculation and evaluation of power system reliability, and effectively improves the efficiency of large-scale power system reliability evaluation;

[0048] The present application proposes a method, system, device and medium for evaluating the reliability of power system status enumeration, which has a faster convergence speed and a smoother convergence process, improves the accuracy and reliability of the reliability evaluation results, facilitates timely and accurate decision-making, and provides technical support for ensuring the safe and stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The drawings described herein are used to provide a further understanding of the embodiments of the present application, constitute a part of the present application, and do not constitute a limitation on the embodiments of the present application. In the drawings:

[0050] Figure 1 A flow chart of the evaluation method proposed in the embodiment of the present application;

[0051] Figure 2 This is a functional block diagram of the evaluation system proposed in the embodiment of the present application;

[0052] Figure 3 It is the IEEE-118 system structure and the corresponding transmission line fault numbering diagram;

[0053] Figure 4A comparison chart of evaluation results of a traditional algorithm and an improved algorithm proposed in this embodiment;

[0054] Figure 5 This is a diagram of iterative calculation results of the improved algorithm proposed in this embodiment;

[0055] Figure 6 It is a graph showing the iterative convergence process of a traditional algorithm and the improved algorithm proposed in this embodiment; wherein (a) is the convergence process curve of the improved algorithm proposed in this embodiment; and (b) is the convergence process curve of the traditional algorithm. DETAILED DESCRIPTION

[0056] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with examples and drawings. The illustrative implementation scheme of the present application and its description are only used to explain the present application and are not intended to limit the present application.

[0057] Example:

[0058] In order to improve the reliability assessment efficiency of complex power systems and ensure the stable and safe operation of the power grid, this embodiment proposes a power system state enumeration reliability assessment method, which uses a reliability assessment algorithm based on boundary iterative improved calculation, can quickly and accurately realize the calculation and assessment of power system reliability, and improve the calculation and assessment efficiency.

[0059] like Figure 1 As shown, the method proposed in this embodiment specifically includes the following steps:

[0060] Step 100: construct a reliability index calculation function based on the impact increment state enumeration method.

[0061] The reliability index calculation function constructed is:

[0062]

[0063] Where n is the enumeration order, s is the enumeration state, M is the total number of transmission lines, is an n-order subset of a set containing M elements, p v is the failure probability of the vth transmission line, is the value of the reliability index at time t, is the reliability index impact increment under the n-th order fault state s at time t.

[0064] in, The calculation method is:

[0065]

[0066] in, is the reliability index increment under the n-order fault state s at time t, is the reliability index at time t n s The reliability index impact increment under the fault state u, n s is the number of faulty transmission lines in fault state s, Card(u) is the number of faulty transmission lines in fault state u, is the fault state s n s Subset of order.

[0067] The traditional enumeration method will increase the enumeration order exponentially as the scale of the power system expands, and the complexity and calculation of enumerating all states will increase exponentially, reducing the evaluation efficiency. However, this embodiment adopts the impact increment state enumeration method, whose enumeration order is 3, which solves the problem that the number of enumeration calculations in the traditional enumeration method increases exponentially with the enumeration order, and can obtain reliability evaluation results in a timely and effective manner.

[0068] Step 200: divide the reliability index into various order components according to the reliability index calculation function.

[0069] The division method of each order component is:

[0070]

[0071] in, are the first-order component, second-order component and third-order component of the reliability index respectively; the total number of calculations is Indicates the number of elements required to take out 1 element from M elements; It represents the number of elements required to take out 2 elements from M elements; It represents the number of elements required to take out 3 elements from M elements.

[0072] Step 300, using the reliability index calculation function and the component function corresponding to the reliability index calculation function to calculate the first-order component and the second-order component of the reliability index, and taking the sum of the first-order component and the second-order component of the reliability index as the reliability index benchmark result.

[0073] The reliability index calculation function of step 200 is used to calculate the corresponding component function to obtain the first-order component of the reliability index under n=1,2 and the second-order component The reliability index benchmark result is:

[0074] Step 400: construct an upper and lower bound iterative calculation sequence based on the reliability index benchmark results according to preset conditions.

[0075] The following conditions should be met to construct the upper and lower boundary iterative sequence:

[0076] (1) The upper bound iteration sequence is monotonically decreasing;

[0077] (2) The lower bound iteration sequence is monotonically increasing.

[0078] When the constructed upper and lower bounds iterative calculation series meet the above preset conditions, the third-order failure probability set Rearrange in descending order:

[0079]

[0080] in, Represents the third-order subset of the set with a total number of transmission lines M.

[0081] This further improves the convergence rate and thus the evaluation efficiency.

[0082] Based on this, the upper and lower bounds are iterated and calculated according to the reliability index benchmark results.

[0083] Among them, the upper bound iteration sequence is:

[0084]

[0085] The lower bound iteration sequence is:

[0086]

[0087] in, is the maximum estimated value, is the minimum estimated value, k is the number of iterative calculations, is the i-th element in the rearranged third-order failure probability set, It represents the third-order fault element corresponding to the i-th fault element at a specific calculation time t, with the power system load loss as the resilience evaluation index. The impact of incremental results.

[0088] For the upper bound iterative sequence, we have:

[0089] It is a strictly monotonically decreasing sequence that meets the preset conditions.

[0090] For the lower bound iterative sequence, we have:

[0091] It is a strictly monotonically increasing sequence that meets the preset conditions.

[0092] Step 500, taking the absolute value of the distance of the upper and lower bounds iteratively calculated series less than the allowable error as the objective function, iteratively calculate the upper and lower bounds evaluation results.

[0093] The absolute value of the distance between the upper boundary iterative calculation series and the lower boundary iterative calculation series is:

[0094]

[0095] Then we have:

[0096] That is to say, it is ensured that the calculation results are within the given allowable error range.

[0097] in, It represents the allowable error of the algorithm setting, and k1 is the convergence parameter.

[0098] Step 600: If the upper and lower bound evaluation results under the given convergence parameters obtained by iterative calculation meet the evaluation accuracy, the evaluation results are output; otherwise, the convergence parameters are adjusted to continue iterative calculation until the convergence conditions and evaluation accuracy are met and the results are output. Specifically, step 600 can increase the convergence parameters, that is, reduce the allowable error to obtain a more accurate evaluation result.

[0099] Furthermore, the method proposed in this embodiment also includes:

[0100] Step 700, based on the output power system reliability assessment results, analyze the key lines that cause the system reliability to decrease, and reinforce the lines, and finally improve the overall reliability of the system after the lines are reinforced. It should be noted that the key line analysis that causes the system reliability to decrease in this step 800 can be analyzed manually, or other existing related performance analysis technologies can be used for further analysis and determination. It is not a problem considered in this application, so it will not be described in detail.

[0101] The method proposed in this embodiment adopts the impact incremental state enumeration method to construct a reliability index calculation function, and combines it with boundary iterative calculation to quickly realize the calculation and evaluation of power system reliability, improve the calculation and evaluation efficiency, and then make timely and accurate decisions, providing technical support for ensuring the stable and safe operation of the power grid.

[0102] Based on the same technical concept as above, this embodiment also proposes a power system state enumeration reliability assessment system, such as Figure 2 As shown, the system proposed in this embodiment includes:

[0103] The index calculation unit constructs a reliability index calculation function based on the influence increment state enumeration method. The constructed reliability index calculation function is as described in step 100 of the above method, and will not be described in detail here.

[0104] The index division unit divides the reliability index into various order components according to the reliability index calculation function, specifically dividing the reliability index into first order component, second order component and third order component, as described in step 200 of the above method, which will not be described in detail here.

[0105] The benchmark calculation unit calculates the first-order component and the second-order component of the reliability index, and takes the sum of the first-order component and the second-order component of the reliability index as the reliability index benchmark result.

[0106] The boundary construction unit constructs the upper and lower bounds iterative calculation sequence based on the reliability index benchmark result according to the preset conditions. The specific construction method is as described in the above step 400, which will not be repeated here.

[0107] The iterative calculation unit uses the absolute value of the distance between the upper and lower bounds iterative calculation series less than the allowable error as the objective function, and iteratively calculates the upper and lower bound evaluation results.

[0108] And, an output unit, which determines whether the upper and lower bound evaluation results under the given convergence parameters obtained by the iterative calculation unit meet the evaluation accuracy. If so, the evaluation result is output; otherwise, the convergence parameter is adjusted to continue the iterative calculation until the convergence conditions and evaluation accuracy are met and the result is output.

[0109] Furthermore, the system proposed in this embodiment also includes:

[0110] The performance improvement unit analyzes the key lines that cause the system reliability to decrease according to the power system reliability evaluation result output by the output unit, and reinforces the lines, thereby finally improving the overall reliability of the system after the lines are reinforced.

[0111] This embodiment takes the transmission line failure probability set in the IEEE-118 system caused by a natural disaster as an example, performs algorithm programming calculation on MATLAB and verifies the effectiveness of the above method proposed in this embodiment.

[0112] The IEEE-118 system structure and the corresponding transmission line fault numbers are as follows: Figure 3 As shown in the figure, among the faults caused this time, there are 26 first-order faults, 325 second-order faults, and 2600 third-order faults. The accurate result calculated by the traditional enumeration algorithm in 24 hours is taken as the standard result.

[0113] The results calculated by the traditional enumeration algorithm are compared with the results calculated by the method proposed in this embodiment. Figure 4 As shown, Figure 4 In the example, the convergence parameter k1 = 1, from Figure 4 It can be seen that under the given convergence parameter condition, the error between the calculated result and the accurate result is very small, which shows that the method proposed in this embodiment is feasible.

[0114] The upper and lower bounds iterative calculation results in the method proposed in this embodiment are as follows: Figure 5shown.

[0115] Table 1 shows the influence of the convergence parameter on the computational efficiency and computational accuracy. As the convergence parameter increases, the maximum relative error and the average relative error are reduced, indicating that increasing the convergence parameter will perform more iterative calculations to get closer to the real result. But at the same time, the calculation time will also increase, thereby bringing about a decrease in computational efficiency. Therefore, in practical applications, the method proposed in this embodiment can be used by engineering researchers to set reasonable convergence parameters according to the actual engineering practice to obtain a balance between computational accuracy and computational efficiency.

[0116] Table 1

[0117]

[0118] Furthermore, the comparison of the convergence process between the method proposed in this embodiment and the traditional enumeration method is as follows: Figure 6 As shown, compared with the traditional enumeration method, the method proposed in this embodiment has a faster convergence speed and a smoother convergence process, improves the accuracy and reliability of the reliability evaluation result, has a smooth characteristic and reduces the convergence oscillation phenomenon.

[0119] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0120] 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.

[0121] 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.

[0122] 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. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0123] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for evaluating the reliability of power system status enumeration, characterized in that: The evaluation methods include: Based on the impact increment state enumeration method, a reliability index calculation function is constructed; According to the reliability index calculation function, the reliability index is divided into components of various orders; The first-order component and the second-order component of the reliability index are calculated, and the sum of the first-order component and the second-order component of the reliability index is used as a reliability index benchmark result; According to preset conditions, constructing an upper and lower bound iterative calculation sequence based on the reliability index benchmark results; The upper and lower bounds are evaluated by iteratively calculating the absolute value of the distance between the upper and lower bounds and the allowable error as the objective function; the allowable error is the ratio of the reliability index benchmark result to the convergence parameter; If the upper and lower bound evaluation results under the given convergence parameters obtained by iterative calculation meet the evaluation accuracy, the evaluation results are output; otherwise, the convergence parameters are adjusted to continue the iterative calculation until the convergence conditions and evaluation accuracy are met and the results are output.

2. A method for evaluating the reliability of power system status enumeration according to claim 1, characterized in that: The evaluation method also includes: Based on the output power system reliability assessment results, the key lines that cause reduced system reliability are analyzed and reinforced, ultimately achieving improved overall system reliability after line reinforcement.

3. A method for evaluating the reliability of power system status enumeration according to claim 1 or 2, characterized in that: The reliability index calculation function constructed is: Where n is the enumeration order; s is the enumeration state; M is the total number of transmission lines; is an n-order subset of a set containing M elements; p v is the failure probability of the vth transmission line; is the value of the reliability index at time t; is the reliability index impact increment under the n-th order fault state s at time t.

4. A method for evaluating the reliability of power system status enumeration according to claim 3, characterized in that: According to the reliability index calculation function, the reliability index is divided into various order components, which are expressed as: in, They are the first-order component, second-order component and third-order component of the reliability index respectively.

5. A method for evaluating reliability of power system status enumeration according to claim 1 or 2, characterized in that: The above-mentioned constructing the upper and lower bounds iterative calculation sequence based on the reliability index benchmark result according to the preset conditions specifically includes: The preset conditions include: The upper bound iteration sequence is monotonically decreasing; And, the lower bound iteration sequence is monotonically increasing; Rearrange the third-order failure probability set in descending order; The upper and lower bounds iterative calculation sequence constructed according to the reliability index benchmark results is: Among them, the upper bound iteration sequence is: The lower bound iteration sequence is: in, is the maximum estimated value, is the minimum estimated value, The reliability index is the benchmark result.

6. A method for evaluating reliability of power system status enumeration according to claim 5, characterized in that: The objective function is expressed as: Among them, δ1 is the allowable error, and k1 is the convergence parameter.

7. A power system state enumeration reliability assessment system, characterized in that: The evaluation system comprises: An index calculation unit, wherein the index calculation unit constructs a reliability index calculation function based on an impact increment state enumeration method; An index dividing unit, wherein the index dividing unit divides the reliability index into components of various orders according to the reliability index calculation function; A benchmark calculation unit, wherein the benchmark calculation unit calculates the first-order component and the second-order component of the reliability index, and takes the sum of the first-order component and the second-order component of the reliability index as the reliability index benchmark result; A boundary construction unit, wherein the boundary construction unit constructs an upper and lower bound iterative calculation sequence based on the reliability index benchmark result according to preset conditions; An iterative calculation unit, wherein the iterative calculation unit takes the absolute value of the distance between the upper and lower bounds iterative calculation series less than the allowable error as the objective function, and iteratively calculates the upper and lower bounds evaluation results; the allowable error is the ratio of the reliability index benchmark result to the convergence parameter; And, an output unit, which determines whether the upper and lower bound evaluation results calculated under given convergence parameters meet the evaluation accuracy. If so, the evaluation results are output; otherwise, the convergence parameters are adjusted to continue iterative calculation until the convergence conditions and evaluation accuracy are met and the results are output.

8. A power system state enumeration reliability assessment system according to claim 7, characterized in that: The evaluation system further comprises: The performance improvement unit analyzes the key circuits that cause the system reliability to decrease according to the output reliability evaluation results, and reinforces the key circuits, thereby finally improving the overall reliability of the system after the circuit reinforcement.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images