阅读说明：本技术 基于层级模型和改进灰狼优化算法的配电网故障定位方法 (power distribution network fault positioning method based on hierarchical model and improved wolf optimization algorithm ) 是由 蒋伟 甄永琦 李鹏博 陈理宁 杨铠旭 于 2019-08-09 设计创作，主要内容包括：本发明涉及一种基于层级模型和改进灰狼优化算法的配电网故障定位方法,本发明首先在确定编码规则前提下,构造了能够适应多分布式电源接入的开关函数。然后根据发生故障后开关函数值的特点,建立配电网的层级模型,并据此建立相应的评价函数。再针对灰狼优化算法收敛速度较慢的问题,结合故障定位模型,在基本二进制灰狼优化算法位置更新公式中引入了交叉和变异操作,提高了算法的收敛速度和寻优精度。最后将层级模型的建立和改进后的灰狼优化算法应用于含分布式电源的配电网故障区段定位中。本发明采用的层级模型和改进的灰狼算法能够快速、准确的实现配电网故障区段定位,并且具有一定的容错性,适用于复杂的含分布式电源的配电网故障定位。(The invention relates to a power distribution network fault positioning method based on a hierarchical model and an improved wolf optimization algorithm. And then, establishing a hierarchical model of the power distribution network according to the characteristics of the switching function values after the faults occur, and establishing a corresponding evaluation function according to the hierarchical model. Aiming at the problem that the convergence speed of the gray wolf optimization algorithm is low, the method introduces cross and variation operations in a basic binary gray wolf optimization algorithm position updating formula by combining a fault positioning model, and improves the convergence speed and the optimization precision of the algorithm. And finally, applying the established hierarchical model and the improved gray wolf optimization algorithm to the positioning of the fault section of the power distribution network containing the distributed power supply. The invention adopts a hierarchical model and an improved wolf algorithm, can quickly and accurately realize the fault section positioning of the power distribution network, has certain fault tolerance and is suitable for the fault positioning of the complex power distribution network containing the distributed power supply.)

1. A power distribution network fault positioning method based on a hierarchical model and an improved gray wolf optimization algorithm is characterized by comprising the following steps:

step 1: setting a corresponding coding rule when a fault occurs for a power distribution network containing a distributed power supply;

step 2: establishing a switching function suitable for the access of the distributed power supply according to the coding rule;

and step 3: establishing a hierarchical model of the power distribution network and a corresponding evaluation function according to the equivalent basis obtained by the switching function;

And 4, step 4: combining a hierarchical model of the power distribution network and a corresponding evaluation function, and improving a wolf optimization algorithm by introducing cross operation and mutation operation;

and 5: and positioning a fault section for the power distribution network containing the distributed power supply by utilizing the improved grey wolf optimization algorithm.

2. The method for power distribution network fault location based on the hierarchical model and the improved grey wolf optimization algorithm as claimed in claim 1, wherein the encoding rule in step 1 specifically includes: the direction of the power supply of the power grid pointing to the user is specified as the positive direction, and if the FTU detects the directionwhen the fault current direction of the switch j is detected to be consistent with the specified positive direction, the switch state I is detected_j1, if the positive direction is opposite, the switch state I_jis-1, when the FTU does not detect fault current, then switch state I_jis 0 and takes a switch j as a demarcation point to divide the power distribution network into two parts including a distributed power supply, namely an upper half area of the switch j and the rest part of the power distribution network, namely a lower half area of the switch j.

3. the method for locating the fault of the power distribution network based on the hierarchical model and the improved grey wolf optimization algorithm is characterized in that the switching function in the step 2 is described by the formula:

In the formula, Π represents a logical or operation,AndRespectively showing the switching functions of the upper half circuit and the lower half circuit of the jth switch,Representing the switching function of the jth switch, N₁And N₂respectively representing the total number of feeder sections in the upper and lower half regions, M₁and M₂respectively representing the total number of power supplies in the upper and lower half regions, x, of the switch j_jdAnd x_juRespectively representing the switch j to the lower and upper half-zone feeder zonessegment state value, K_uand K_dRespectively representing the power switching coefficients of the upper half area and the lower half area of the switch j, if the power is put into operation, taking 1, otherwise, taking 0,AndAnd the state values of feeder line sections passing through the paths from the switch No. j to the upper half power supply and the lower half power supply are respectively represented.

4. The method for locating the fault of the power distribution network based on the hierarchical model and the improved grey wolf optimization algorithm as claimed in claim 1, wherein the hierarchical model in the step 3 is a hierarchical model formed by externally equating each region to a two-port network and equationally simplifying a complex power distribution network according to the established equivalent ports.

5. The method for locating the fault of the power distribution network based on the hierarchical model and the improved grey wolf optimization algorithm according to claim 1, wherein the evaluation function in the step 3 is as follows:

wherein Fit (x) represents an evaluation function, I_jfault current information representing the jth switch uploaded by the FTU,and the switching function of the jth switch is represented, J represents the total number of switches in the power distribution network, K represents the total number of feeder line sections in the power distribution network, mu represents a weight coefficient, x (K) represents the fault state of the kth section of line, and the fault state is 1 when the fault occurs, and is 0 otherwise.

6. The method for locating the fault of the power distribution network based on the hierarchical model and the improved grey wolf optimization algorithm as claimed in claim 1, wherein the location updating formula of the grey wolf optimization algorithm in the step 4 is as follows:

Wherein sigmoid represents a conversion function, x_d(t +1) represents the updated position of the gray wolf after t iterations in d-dimension, and rand represents [0,1 ]]Random numbers, X, distributed uniformly within₁、X₂And X₃Representing the respective position vectors of the three wolfs in the gray wolf optimization algorithm.

7. The method for locating the fault of the power distribution network based on the hierarchical model and the improved grey wolf optimization algorithm is characterized in that the cross operation in the step 4 is described by the formula:

C_l＝0.3×F_i,best

In the formula (I), the compound is shown in the specification,Indicating the location of the d-th dimension of the ith gray wolf,Represents the position of the d-th dimension of the first gray wolf, wherein l is [1, 2., G ]]the random number in (1) is selected,0,1 of d-dimension representing i-th wolf]Random numbers, C, distributed uniformly within_ldenotes the cross probability, F_iDenotes the fitness value of the ith wolf, F_worstAnd F_bestRespectively representing the worst fitness and the best fitness value of the current iteration.

8. The method for locating the fault of the power distribution network based on the hierarchical model and the improved grey wolf optimization algorithm is characterized in that the mutation operation in the step 4 is described by the following formula:

η＝0.06×F_i,best

In the formula (I), the compound is shown in the specification,denotes the d-dimension position, x, of the ith wolf after the crossover operation_gbest,dRepresents the optimal individual for the d dimension, q, throughout the iteration up to now₁and q is₂Is [1,2,. ] G]Random number of (1), r₃Is [0,1 ]]and η represents the variation probability.

9. the power distribution network fault location method based on the hierarchical model and the improved grey wolf optimization algorithm as claimed in claim 1, wherein the step 5 specifically comprises the following sub-steps:

Step 51: according to the number of feeder sections of the power distribution network, setting a population scale and the maximum iteration times, and randomly generating a swing factor and a convergence factor in a search space;

step 52: generating an initialization population in a search space;

step 53: calculating the fitness value of each wolf individual in the group by using an evaluation function, sorting all the fitness values, selecting and updating the optimal value of the individual, and recording chalks at the positions of the wolf individuals with the fitness values arranged at the first 3 positions as alpha, beta and delta;

Step 54: updating the individual positions of the wolfs and simultaneously carrying out cross and mutation operations;

Step 55: judging whether the algorithm reaches the maximum iteration times, if not, returning to the step 53, if the iteration maximum is reached, outputting the optimal solution, and ending the algorithm;

Step 56: and searching in the fault area by using an exhaustion method according to the fault area positioning result corresponding to the output optimal solution to obtain the positioning result of the fault area, returning to the fault area for positioning if the positioning result of the fault area does not accord with the fault area positioning result, and carrying out the fault area positioning process again.

Technical Field

the invention relates to the technical field of power distribution networks with distributed power sources, in particular to a power distribution network fault positioning method based on a hierarchical model and an improved wolf optimization algorithm.

Background

The power supply reliability of the power distribution network is continuously improved along with the development of the smart power grid, and the fault location research applied to the traditional power distribution network is relatively mature. However, in recent years, with the fact that a large number of novel distributed power sources such as solar energy and wind energy are connected into a power distribution network, a traditional single power supply radiation network becomes a complex multi-power supply network, and a traditional fault section positioning method is not suitable any more.

In order to ensure the reliability of the power distribution network and reduce the influence of line faults on the production and life of users as much as possible, fault sections must be found out quickly and accurately and measures must be taken to remove faults in time. With the application of feeder terminal units in power distribution networks, the positioning of fault sections by using fault information uploaded by the feeder terminal units is widely researched.

Disclosure of Invention

The invention aims to solve the problem that a traditional fault positioning method is not applicable after a distributed power supply is widely connected to a power distribution network, and provides the power distribution network fault positioning method based on a hierarchical model and an improved gray wolf optimization algorithm.

The purpose of the invention can be realized by the following technical scheme:

A power distribution network fault positioning method based on a hierarchical model and an improved gray wolf optimization algorithm comprises the following steps:

Step 1: setting a corresponding coding rule when a fault occurs for a power distribution network containing a distributed power supply;

step 2: establishing a switching function suitable for the access of the distributed power supply according to the coding rule;

and step 3: establishing a hierarchical model of the power distribution network and a corresponding evaluation function according to the equivalent basis obtained by the switching function;

And 4, step 4: combining a hierarchical model of the power distribution network and a corresponding evaluation function, and improving a wolf optimization algorithm by introducing cross operation and mutation operation;

and 5: and positioning a fault section for the power distribution network containing the distributed power supply by utilizing the improved grey wolf optimization algorithm.

Further, the encoding rule in step 1 specifically includes: the direction of the power supply of the power grid pointing to the user is specified as the positive direction, and if the FTU detects that the fault current direction of the switch j is consistent with the specified positive direction, the switch state I is set_j1, if the positive direction is opposite, the switch state I_jIs-1, when the FTU does not detect fault current, then switch state I_jis 0 and takes a switch j as a demarcation point to divide the power distribution network into two parts including a distributed power supply, namely an upper half area of the switch j and the rest part of the power distribution network, namely a lower half area of the switch j.

Further, the switching function in step 2 is described by the formula:

In the formula, Π represents a logical or operation,Andrespectively showing the switching functions of the upper half circuit and the lower half circuit of the jth switch,Representing the switching function of the jth switch, N₁And N₂Respectively representing the total number of feeder sections in the upper and lower half regions, M₁and M₂respectively representing the total number of power supplies in the upper and lower half regions, x, of the switch j_jdAnd x_juRespectively representing the state values of the switch j to the lower and upper half feeder sections, K_uAnd K_drespectively representing the power switching coefficients of the upper half area and the lower half area of the switch j, if the power is put into operation, taking 1, otherwise, taking 0,AndAnd the state values of feeder line sections passing through the paths from the switch No. j to the upper half power supply and the lower half power supply are respectively represented.

further, the hierarchical model in step 3 is a hierarchical model formed by externally equating each region to be a two-port network and equivalently simplifying the complex distribution network according to the established equivalent ports.

Further, the evaluation function in step 3 is:

Wherein Fit (x) represents an evaluation function, I_jFault current information representing the jth switch uploaded by the FTU,and the switching function of the jth switch is represented, J represents the total number of switches in the power distribution network, K represents the total number of feeder line sections in the power distribution network, mu represents a weight coefficient, x (K) represents the fault state of the kth section of line, and the fault state is 1 when the fault occurs, and is 0 otherwise.

Further, the location update formula of the grayish wolf optimization algorithm in the step 4 is as follows:

Wherein sigmoid represents a conversion function, x_d(t +1) represents the updated position of the gray wolf after t iterations in d-dimension, and rand represents [0,1 ]]Random numbers, X, distributed uniformly within₁、X₂and X₃Representing the respective position vectors of the three wolfs in the gray wolf optimization algorithm.

further, the interleaving operation in step 4 describes the formula as:

C_l＝0.3×F_i,best

in the formula (I), the compound is shown in the specification,Indicating the location of the d-th dimension of the ith gray wolf,represents the position of the d-th dimension of the first gray wolf, wherein l is [1, 2., G ]]The random number in (1) is selected,0,1 of d-dimension representing i-th wolf]Random numbers, C, distributed uniformly within_ldenotes the cross probability, F_iDenotes the fitness value of the ith wolf, F_worstAnd F_bestRespectively representing the worst fitness and the best fitness value of the current iteration.

Further, the mutation operation in step 4 describes the formula:

η＝0.06×F_i,best

in the formula (I), the compound is shown in the specification,Denotes the d-dimension position, x, of the ith wolf after the crossover operation_gbest,dRepresents the optimal individual for the d dimension, q, throughout the iteration up to now₁And q is₂Is [1,2,. ] G]Random number of (1), r₃Is [0,1 ]]And η represents the variation probability.

Further, the step 5 specifically includes the following sub-steps:

Step 51: according to the number of feeder sections of the power distribution network, setting a population scale and the maximum iteration times, and randomly generating a swing factor and a convergence factor in a search space;

Step 52: generating an initialization population in a search space;

Step 53: calculating the fitness value of each wolf individual in the group by using an evaluation function, sorting all the fitness values, selecting and updating the optimal value of the individual, and recording chalks at the positions of the wolf individuals with the fitness values arranged at the first 3 positions as alpha, beta and delta;

step 54: updating the individual positions of the wolfs and simultaneously carrying out cross and mutation operations;

step 55: judging whether the algorithm reaches the maximum iteration times, if not, returning to the step 53, if the iteration maximum is reached, outputting the optimal solution, and ending the algorithm;

step 56: and searching in the fault area by using an exhaustion method according to the fault area positioning result corresponding to the output optimal solution to obtain the positioning result of the fault area, returning to the fault area for positioning if the positioning result of the fault area does not accord with the fault area positioning result, and carrying out the fault area positioning process again.

Compared with the prior art, the invention has the following advantages:

(1) According to the invention, on the premise of determining the coding rule, a switching function capable of adapting to the access of multiple distributed power supplies is constructed. And then, according to the characteristics of the switching function values after the faults occur, a hierarchical model of the power distribution network is established, the dimensionality of the problems is effectively reduced, and a corresponding evaluation function is established according to the dimensionality. For a power distribution network containing a distributed power supply, when a short-circuit fault occurs at a certain position of a line, fault overcurrent in multiple directions can occur in the power distribution network, and the traditional coding mode is not applicable any more. The direction of the power supply of the power grid pointing to the user is defined as the positive direction. And after determining the fault current information of each switch according to the coding rule, establishing a function expression to reflect the incidence relation between the line and the switch, and realizing the conversion between the switch fault current out-of-limit information and the line fault state. The switching function provided by the invention can be suitable for a complex power distribution network model, and the problem that the traditional switching function cannot be suitable is solved.

(2) the coding rule and the construction of the switching function can ensure that when a single-point or double-point fault occurs in one area, the influence on the switching function values of other areas is unchanged. Accordingly, each region can be equivalent to one two-port to the outside. The hierarchical model provided by the invention can effectively simplify the complex power distribution network, reduce the dimensionality of problem solving and quickly find out the fault position.

(3) Aiming at the problem that the convergence speed of the gray wolf optimization algorithm is low, the fault positioning model is combined, the cross and variation operations are introduced into the basic binary gray wolf optimization algorithm position updating formula, and the convergence speed and the optimization precision of the algorithm are improved. The improved binary grayish wolf optimization algorithm provided by the invention can effectively avoid local optimization and accelerate convergence speed, and can more quickly and accurately position a fault position.

(4) The method applies the establishment of the hierarchical model and the improved grey wolf optimization algorithm to the positioning of the fault section of the power distribution network containing the distributed power supply, realizes the fault positioning of the power distribution network containing the distributed power supply by integrating the hierarchical model and improving the binary grey wolf algorithm, can quickly and accurately realize the positioning of the fault section of the power distribution network, has certain fault tolerance, and is suitable for the fault positioning of the complex power distribution network containing the distributed power supply.

Drawings

FIG. 1 is a schematic diagram of a complex power distribution network model structure with distributed power sources according to the present invention;

FIG. 2 is a schematic diagram of a simplified power distribution network hierarchical model structure for a complex power distribution network model with distributed power sources in the present invention;

fig. 3 is a flow chart of the fault location of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

For a power distribution network containing a distributed power supply, when a short-circuit fault occurs at a certain position of a line, fault overcurrent in multiple directions can occur in the power distribution network, and the traditional coding mode is not applicable any more. The direction of the power supply of the power grid pointing to the user is defined as the positive direction. The direction of the power supply of the power grid pointing to the user is specified as the positive direction, and if the FTU detects that the fault current direction of the switch j is consistent with the specified positive direction, the switch state I is set_j1, if the positive direction is opposite, the switch state I_jis-1, when the FTU does not detect fault current, then switch state I_jIs 0 and takes a switch j as a demarcation point to divide the power distribution network into two parts including a distributed power supply, namely an upper half area of the switch j and the rest part of the power distribution network, namely a lower half area of the switch j.

and after determining the fault current information of each switch according to the coding rule, establishing a function expression to reflect the incidence relation between the line and the switch, and realizing the conversion between the switch fault current out-of-limit information and the line fault state. The change of a network topology structure after the distributed power supply is connected is considered, and a switching function suitable for switching of a plurality of power supplies is adopted:

In the formula, Π represents a logical or operation,AndRespectively showing the switching functions of the upper half circuit and the lower half circuit of the jth switch,Representing the switching function of the jth switch, N₁And N₂respectively representing the total number of feeder sections in the upper and lower half regions, M₁and M₂Respectively representing the total number of power supplies in the upper and lower half regions, x, of the switch j_jdAnd x_juRespectively representing the state values of the switch j to the lower and upper half feeder sections, K_uand K_dRespectively representing the power switching coefficients of the upper half area and the lower half area of the switch j, if the power is put into operation, taking 1, otherwise, taking 0,andThe state values of feeder line sections passing through the paths from the switch No. j to the upper half area power supply and the lower half area power supply are respectively represented, and j is a natural number.

The switching function can be seen that when a single-point or double-point fault occurs in one area, the influence on the switching function values of other areas is unchanged. Accordingly, each region can be equivalent to one two-port to the outside. According to the established equivalent ports, the complex power distribution network (such as the network 1) is equivalent to a simplified hierarchical model (such as the network 2).

After the switching function is determined, a proper evaluation function needs to be established to realize fault section positioning. The process of completing fault section positioning by utilizing the gray wolf optimization algorithm is the process of realizing the optimal approximation of the fault current signal and the switching function. The evaluation function constructed was:

Wherein Fit (x) represents an evaluation function, I_jFault current information representing the jth switch uploaded by the FTU,The switching function of the jth switch is represented, J represents the total number of switches in the power distribution network, K represents the total number of feeder line sections in the power distribution network, mu represents a weight coefficient, the value is set according to the concept of 'minimum set' in the fault diagnosis theory, x (K) represents the fault state of the kth section of line, 1 is taken when a fault occurs, otherwise, 0 is taken, and K is a natural number.

the gray wolf optimization algorithm simulates the predation behavior and the population grade system of the gray wolf in nature, alpha represents the head wolf in the population, beta represents the secondary leading wolf, delta represents the common wolf, and omega represents the bottom wolf. The population grade of the wolfsbane plays a crucial role in the process of realizing the efficient capturing and killing of prey by the population, and the predation process is finished by alpha leading. Firstly, searching, tracking and approaching a prey by a wolf pack in a team mode; then, surrounding the prey from all directions, when the surrounding ring is small enough and perfect, the wolf colony is attacked by the nearest beta and delta of the prey under the command of alpha, when the prey escapes, other individuals supplement the prey, and the following transformation movement of the wolf colony surrounding ring is realized, so that the prey is continuously attacked in all directions; finally capturing prey.

the gray wolf optimization algorithm simulates the predation behavior and the population grade system of the gray wolf in nature, alpha represents the head wolf in the population, beta represents the secondary leading wolf, delta represents the common wolf, and omega represents the bottom wolf. When solving the optimization problem, the number of the gray wolves in the gray wolves group is set as G, and the position of the ith gray wolve in the d-dimensional search space can be represented as X_i＝(X_i1,X_i2,…,X_id). Recording the historical optimal individual in the population as alpha, the suboptimal individual as beta and the third best individualthe body is marked as delta, the rest are marked as omega, and d is a natural number.

the gray wolf colony is caught according to the following formula:

in the formula, X_p(t) shows the location of the prey at the tth iteration; x (t) represents the location of the wolf individual at the tth iteration; the constant C is a swing factor; r is₁and r₂Is [0,1 ]]A random number in between; a is a convergence factor; a is linearly decreased from 2 to 0 as the number of iterations increases, and n is a natural number.

in the wolf pack, the ith wolf usually uses the positions of α, β and δ to determine the direction of the target and update the position. The mathematics are described as follows:

In solving the problem of fault section location, there are only two states 0 or 1 for the fault section state value, so the actual grey wolf location update needs to be mapped to a binary value representation. In the binary grayish optimization algorithm, the location update is performed by the following formula:

wherein sigmoid represents a conversion function, x_d(t +1) represents the updated position of the gray wolf after t iterations in d-dimension, and rand represents [0,1 ]]Random numbers, X, distributed uniformly within₁、X₂And X₃Representing the respective position vectors of the three wolfs in the gray wolf optimization algorithm.

in order to increase the diversity of population individuals after iteration, a binomial crossover operation is carried out on the population individuals. The intersection operation of the d-th dimension of the ith grayish wolf is shown as follows.

C_l＝0.3×F_i,best

In the formula (I), the compound is shown in the specification,indicating the location of the d-th dimension of the ith gray wolf,represents the position of the d-th dimension of the first gray wolf, wherein l is [1, 2., G ]]The random number in (1) is selected,0,1 of d-dimension representing i-th wolf]Random numbers, C, distributed uniformly within_lrepresenting the probability of crossing, being dynamically variable, F_iDenotes the fitness value of the ith wolf, F_worstAnd F_bestrespectively representing the worst fitness and the best fitness value of the current iteration.

The current optimal individual is not changed through a related formula of the cross operation, and the cross probability is in direct proportion to the relative fitness value.

In order to further improve the diversity of the population and prevent the algorithm from falling into the local optimum, the variation operation is performed on the wolf individuals after the crossover, and the definition is as follows:

η＝0.06×F_i,best

In the formula (I), the compound is shown in the specification,denotes the d-dimension position, x, of the ith wolf after the crossover operation_gbest,drepresents the optimal individual for the d dimension, q, throughout the iteration up to now₁and q is₂Is [1,2,. ] G]Random number of (1), r₃Is [0,1 ]]And η represents the variation probability.

If the current individual is smaller than the current global optimal individual fitness value, the current global optimal individual is replaced. According to the related formula of mutation operation, the mutation probability of the current globally optimal individual is 0, and the mutation probability of the worst individual is 0.06.

The whole positioning process of the invention is shown in fig. 3, and the specific working process is as follows:

Description of the basic principles:

after the distribution network is subjected to area division, a fault area can be determined firstly by using an improved wolf algorithm through fault information uploaded by an FTU (fiber to the Unit). After determining the fault area, the solution using the intelligent algorithm is inefficient because the number of sections contained in the area is small, and therefore an exhaustive method is adopted in the location of the fault section.

According to the divided hierarchical model and fault current information uploaded by the FTU, firstly, an improved wolf algorithm is used for positioning a fault area, and a fault section is found in the fault area by using an exhaustion method. In order to improve the positioning accuracy, the output positioning section is compared with the area positioning result, if the output positioning section is consistent with the area positioning result, the positioning result is output, and if the output positioning section is inconsistent with the area positioning result, the area positioning is returned, and the fault positioning is completed again.

The specific process comprises the following steps: after the distribution network is divided into areas, fault areas are determined firstly by using an improved wolf algorithm through fault information uploaded by an FTU (distribution switch monitoring terminal). And then, continuously carrying out fault section positioning in the region by using an exhaustion method, wherein the specific steps are as follows:

(1) And setting a population size N and a maximum iteration number Max according to the number of feeder sections of the distribution network, and randomly generating parameters A, C in a search space.

(2) Generating an initialization population in a search space, i.e. randomly generating N d-dimensional individuals [ X₁,X₂,…,X_N]Each individual consists of 0 or 1.

(3) Calculating the fitness value of each wolf individual in the group according to an evaluation function formula, sequencing all the fitness values, selecting and updating the individual optimal values, and marking the positions of the wolf individuals with 3 bits before the fitness value arrangement as alpha, beta and delta respectively.

(4) Updating the individual positions of the wolf according to a mathematical description formula and a position updating formula in the wolf optimization algorithm, and then carrying out crossover and mutation operations according to description formulas corresponding to the crossover operations and the mutation operations.

(5) And judging whether the algorithm reaches the maximum iteration times. If not, returning to the step (3), and if the iteration maximum value is reached, outputting the optimal solution, and ending the algorithm.

(6) And searching in the area by using an exhaustion method according to the output fault area positioning result to obtain the positioning result of the fault section. And if the section positioning result is not consistent with the area positioning result, returning to the area positioning again, and performing the fault positioning process again.

while the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.