Optimization method and device for neutral point series connection small reactance parameter of autotransformer

Abstract

The invention discloses an optimization method and device for neutral point series connection small reactance parameters of an autotransformer, and relates to the field of neutral point grounding of an electric power system, and the method comprises the steps: obtaining parameter information; calculating a single-phase short-circuit current and a three-phase short-circuit current according to the parameter information; judging whether a condition that the single-phase short-circuit current is greater than the three-phase short-circuit current exists or not, and if so, inhibiting the single-phase short-circuit current by connecting a small reactor in series at a neutral point of the autotransformer; wherein the process of determining the impedance value of the series connection small reactor is as follows: constructing a first sub-objective function with the sum of single-phase short-circuit current of a medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and the manufacturing cost of the series connection small reactor as the minimum; based on the first sub-objective function and the second sub-objective function, in combination with constraint conditions, establishing a multi-objective particle swarm optimization model of the cascaded small reactance; and solving the multi-target particle swarm optimization model by adopting a particle swarm algorithm to obtain an impedance value of the neutral point series connection small reactor.

Description

Technical Field

[0001] The invention relates to the field of neutral point grounding of power systems, and more specifically, to a method and a device for optimizing parameters of a small reactance connected in series with the neutral point of an autotransformer. Background Art

[0002] In the 500kV system, the substation is not only large in scale, but also uses a large number of autotransformers, and the neutral points are all directly grounded. Since the reactance on the medium-voltage side of the autotransformer is usually zero or close to zero, the increase in a large number of grounding points causes the zero-sequence impedance of the 500kV substation to drop sharply, causing the single-phase short-circuit current level of the busbar on the 220kV side of the 500kV substation to increase significantly, exceeding its three-phase short-circuit current level, and even approaching the rated breaking current of the circuit breaker, which seriously affects the power supply reliability and safety of the system and becomes one of the main factors restricting the development of the power grid.

[0003] According to the relevant standards of the power industry, the single-phase short-circuit current level of the medium-voltage busbar can be limited to a safe range by connecting a small reactor in series with the neutral point of the autotransformer. However, the selection of the small reactor value is directly related to the safe, stable operation and economy of the power grid. Since the small reactor connected in series with the neutral point will change the zero-sequence impedance of the system, if the reactor value is too small, the effect of limiting the short-circuit current will not be obvious; if the reactor value is too large, it may cause the neutral point overvoltage to increase, thereby affecting the insulation level of the neutral point. In addition, the investment cost of connecting a small reactor in series is also related to the number of installations and the size of the impedance value. The larger the impedance value and the more installation locations, the higher the investment cost.

[0004] The selection of the parameters of the small reactance connected in series with the neutral point of the autotransformer needs to comprehensively consider the impact on the short-circuit current suppression effect, system voltage stability and investment cost. At present, in actual engineering, the selection is usually based on the empirical value of 1 / 10 to 1 / 3 of the high and medium voltage zero-sequence reactance of the autotransformer, but this range is large and difficult to select reasonably. It is also possible to calculate and compare the short-circuit currents under different reactance values ​​one by one through numerical analysis or short-circuit current calculation procedures, and select the reactance value when the single-phase short-circuit current is less than the three-phase short-circuit current, but there are problems such as cumbersome calculations and low calculation efficiency. In addition, the above methods are all for the selection of parameters of the small reactance connected in series with a single autotransformer, and do not consider the suppression effect of the overall single-phase short-circuit current of the power system. At the same time, the installation of the small reactance in series also lacks further consideration of the investment cost. Summary of the invention

[0005] The purpose of the present invention is to provide a method and device for optimizing the parameters of a small reactance connected in series with the neutral point of an autotransformer. The present invention comprehensively considers factors such as the global current limiting effect, the neutral point insulation level and the investment cost of a 500kV power system, and can reduce the investment cost while ensuring the current limiting capability. Compared with the traditional method for selecting the value of the small reactance at the neutral point of an autotransformer, the method can better solve the problem of balancing the current limiting capability and the investment cost, and can provide a guiding reference for the parameter selection of the small reactance connected in series with the autotransformer in a 500kV power system.

[0006] In a first aspect of the present invention, a method for optimizing parameters of a small reactance connected in series with a neutral point of an autotransformer is provided, the method comprising:

[0007] Obtain parameter information on the topology of the power system and substation, generator reactance, load type and size;

[0008] Calculate the single-phase short-circuit current and three-phase short-circuit current of the medium-voltage side bus according to the parameter information;

[0009] Determine whether there is a situation where the single-phase short-circuit current is greater than the three-phase short-circuit current. If so, suppress the single-phase short-circuit current by connecting a small reactance in series with the neutral point of the autotransformer;

[0010] Among them, the impedance value determination process of the series small reactance is as follows: construct a first sub-objective function with the sum of the single-phase short-circuit current of the medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and manufacturing cost of the series small reactance as the minimum; based on the first sub-objective function and the second sub-objective function, combined with pre-configured constraints, a multi-objective particle swarm optimization model of the series small reactance is established; the particle swarm algorithm is used to solve the multi-objective particle swarm optimization model to obtain the impedance value of the neutral point series small reactance of the autotransformer.

[0011] In one implementation, the expression of the second sub-objective function is:

[0012] Where P(j) is the control variable, P∈{0,1}, 0 means no small reactor is installed at the neutral point of the j-th autotransformer, and 1 means a small reactor is installed at the neutral point of the j-th autotransformer; k 1 and k 2 are the installation cost coefficient and manufacturing cost coefficient of the series small reactor respectively; x T (j) represents the impedance value of the small reactance connected in series with the neutral point of the jth autotransformer, f 2 Represents the second sub-objective function.

[0013] In one implementation, the constraint conditions include a single-phase short-circuit current constraint of a busbar on the medium-voltage side of an autotransformer, an impedance value constraint of a series-connected small reactance, and an insulation level constraint of a neutral point of the autotransformer.

[0014] In one implementation, the insulation level constraint is expressed as:

[0015] Among them, U 0L is the effective value of the lightning impulse withstand voltage at the neutral point of the transformer; α is the line capacitance coefficient; γ is the transformer oscillation coefficient, U ph is the effective value of the maximum phase voltage in the power system operation, and K is the grounding coefficient.

[0016] In one implementation, before using the particle swarm algorithm to solve the multi-objective particle swarm optimization model, the method further includes: using a dynamic inertia factor to adjust a weight parameter of the particle swarm algorithm.

[0017] In a second aspect of the present application, a device for optimizing the parameters of a small reactance connected in series with the neutral point of an autotransformer is provided, the device comprising:

[0018] Parameter information module, used to obtain parameter information of the power system and substation topology, generator reactance, load type and size;

[0019] A current calculation module is used to calculate the single-phase short-circuit current and three-phase short-circuit current of the medium-voltage side bus according to parameter information;

[0020] The impedance optimization module is used to determine whether there is a situation where the single-phase short-circuit current is greater than the three-phase short-circuit current. If so, the single-phase short-circuit current is suppressed by connecting a small reactance in series at the neutral point of the autotransformer;

[0021] Among them, the impedance value determination process of the series small reactance is as follows: construct a first sub-objective function with the sum of the single-phase short-circuit current of the medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and manufacturing cost of the series small reactance as the minimum; based on the first sub-objective function and the second sub-objective function, combined with pre-configured constraints, a multi-objective particle swarm optimization model of the series small reactance is established; the particle swarm algorithm is used to solve the multi-objective particle swarm optimization model to obtain the impedance value of the neutral point series small reactance of the autotransformer.

[0022] In one implementation, the expression of the second sub-objective function is:

[0023] Where P(j) is the control variable, P∈{0,1}, 0 means no small reactor is installed at the neutral point of the j-th autotransformer, and 1 means a small reactor is installed at the neutral point of the j-th autotransformer; k 1 and k 2 are the installation cost coefficient and manufacturing cost coefficient of the series small reactor respectively; x T (j) represents the impedance value of the small reactance connected in series with the neutral point of the jth autotransformer, f 2Represents the second sub-objective function.

[0024] In one implementation, the constraint conditions include a single-phase short-circuit current constraint of a busbar on the medium-voltage side of an autotransformer, an impedance value constraint of a series-connected small reactance, and an insulation level constraint of a neutral point of the autotransformer.

[0025] In one implementation, the insulation level constraint is expressed as:

[0026] Among them, U 0L is the effective value of the lightning impulse withstand voltage at the neutral point of the transformer; α is the line capacitance coefficient; γ is the transformer oscillation coefficient, U ph is the effective value of the maximum phase voltage in the power system operation, and K is the grounding coefficient.

[0027] In one implementation, the device further includes: a parameter optimization module, configured to adjust the weight parameters of the particle swarm algorithm using a dynamic inertia factor.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] In the optimization method and device for the parameters of the autotransformer neutral point series small reactance provided in the embodiment of the present invention, the global current limiting effect, neutral point insulation level and investment cost of the 500kV power system are comprehensively considered, and the investment cost can be reduced while ensuring the current limiting capability. Compared with the traditional autotransformer neutral point small reactance selection method, it can better solve the problem of balancing current limiting and investment cost, and can provide guidance and reference for the parameter selection of the autotransformer series small reactance in the 500kV power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of the present invention, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0031] Figure 1 A schematic flow chart of a method for optimizing parameters of a small reactance connected in series with the neutral point of an autotransformer provided by an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of a process for solving an optimization model using a particle swarm algorithm according to an embodiment of the present invention;

[0033] Figure 3 A principle block diagram of a device for optimizing parameters of a small reactance connected in series with the neutral point of an autotransformer provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0035] It should be noted that the terms "include" or "may include" used in various embodiments of the present invention indicate the presence of the function, operation or element applied for, and do not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present invention, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0036] It should be understood that terms such as "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] Please refer to Figure 1 , Figure 1 A flow chart of a method for optimizing the parameters of a small reactance connected in series with the neutral point of an autotransformer provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method includes:

[0038] S101, obtaining parameter information of the topological structure of the power system and the substation, the reactance of the generator, and the type and size of the load.

[0039] In this embodiment, the number of autotransformers in the 500kV power system and the number of medium voltage busbars connected thereto are counted, which are recorded as M and N respectively; secondly, parameter information of the power system and the substation is obtained, and the parameter information includes voltage, short-circuit point impedance, power supply impedance, etc. These are well-known parameters in the technical field, and no redundant description is given in this embodiment.

[0040] S102, calculating the single-phase short-circuit current and the three-phase short-circuit current of the medium-voltage side bus according to the parameter information;

[0041] In this embodiment, the single-phase short-circuit current and the three-phase short-circuit current of the medium-voltage side bus are common knowledge in the technical field, and no redundant explanation is given in this embodiment.

[0042] S103, determining whether a single-phase short-circuit current is greater than a three-phase short-circuit current, and if so, suppressing the single-phase short-circuit current by connecting a small reactance in series to the neutral point of the autotransformer;

[0043] Among them, the impedance value determination process of the series small reactance is as follows: construct a first sub-objective function with the sum of the single-phase short-circuit current of the medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and manufacturing cost of the series small reactance as the minimum; based on the first sub-objective function and the second sub-objective function, combined with pre-configured constraints, a multi-objective particle swarm optimization model of the series small reactance is established; the particle swarm algorithm is used to solve the multi-objective particle swarm optimization model to obtain the impedance value of the neutral point series small reactance of the autotransformer.

[0044] In this embodiment, in order to ensure the current limiting capability of the series small reactor and reduce the investment cost of installing the series small reactor, this embodiment establishes a multi-objective particle swarm optimization model of the series small reactor:

[0045] The first sub-objective function f 1 The global current limiting effect of the optimization scheme is measured, which is specifically defined as the sum of the single-phase short-circuit currents of the busbars on the medium-voltage side of the autotransformer in the 500kV system: in, Represents the single-phase short-circuit current of the i-th medium-voltage busbar.

[0046] The second sub-objective function f 2 The economic feasibility of the optimization scheme is measured, which is specifically defined as the installation cost and manufacturing cost of the series small reactor: Where P(j) is the control variable, P∈{0,1}, 0 means no small reactor is installed at the neutral point of the j-th autotransformer, and 1 means a small reactor is installed at the neutral point of the j-th autotransformer; k 1 and k 2 are the installation cost coefficient and manufacturing cost coefficient of the series small reactor respectively; x T (j) represents the impedance value of the small reactance connected in series with the neutral point of the jth autotransformer.

[0047] Specifically, the installation cost coefficient k 1 Take it as 30, the manufacturing cost coefficient k 2 Take it as 1.

[0048] Pre-configured constraints, including:

[0049] The single-phase short-circuit current constraint of the medium-voltage busbar of the autotransformer is:

[0050] The impedance value of the series small reactance is constrained to: 0≤x T (j)≤30,j=1,2,…,M, and x T(j) is an integer.

[0051] The insulation level constraints of the autotransformer neutral point include: Where: I res is the maximum breaking current of the busbar circuit breaker; U 01min U is the effective value of the 1-min power frequency withstand voltage at the neutral point of the transformer; ph is the maximum effective value of the phase voltage in system operation; K is the grounding coefficient, which is the ratio of the zero-sequence reactance to the positive-sequence reactance of the system and is set to 0 <K≤3;U 0L is the effective value of the lightning impulse withstand voltage at the neutral point of the transformer; α is the line capacitance coefficient, usually taken as 0.18~0.2; γ is the transformer oscillation coefficient, usually taken as 1.8.

[0052] In an optimization method for the parameters of the autotransformer neutral point series small reactance provided in an embodiment of the present invention, factors such as the global current limiting effect, neutral point insulation level and investment cost of the 500kV power system are comprehensively considered, and the investment cost can be reduced while ensuring the current limiting capability. Compared with the traditional autotransformer neutral point small reactance selection method, it can better solve the problem of balancing current limiting and investment cost, and can provide guidance and reference for the parameter selection of the autotransformer series small reactance in the 500kV power system.

[0053] Please refer to Figure 2 , Figure 2 The process of solving the optimization model by particle swarm algorithm is shown as follows:

[0054] Initialize the particle population speed and position, set the algorithm parameters and control variable parameters, including: particle dimension, population size, inertia weight, learning factor, maximum number of iterations, and initial speed;

[0055] Calculate the objective function f for each particle 1 and f 2 The fitness value of the particle is obtained, and the non-dominated solution is obtained. The optimal position of each particle and the global optimal position are determined according to the particle dominance relationship.

[0056] According to the algorithm's own optimization mechanism, the particle speed and position are updated to form a new sub-population, and individuals are randomly selected for crossover and mutation operations;

[0057] Solve the Pareto optimal solution set and update the optimal position and optimal fitness value of individuals and groups;

[0058] Check whether the maximum number of iterations has been reached. If so, output the Pareto optimal solution set; if not, re-update the particle speed and position, and randomly select individuals for crossover and mutation operations, and continue the cycle calculation until the termination condition is met.

[0059] Furthermore, the dynamic inertia factor is used to adjust the weight parameters as follows:

[0060] Among them, w max and w min are the extreme values ​​of the weight factors; k and k max are the current iteration number and the total number of iterations respectively.

[0061] Furthermore, the particle velocity and position update formula is:

[0062]

[0063] in, is the particle velocity at the k+1th iteration; is the particle position at the k+1th iteration; k is the current number of iterations; w is the inertia weight; c 1 、c 2 is the acceleration factor; r 1 、r 2 is a random number between (0,1); is the individual extreme value of the individual optimal value particle at the kth iteration; is the group extreme value of the group optimal value particle at the kth iteration.

[0064] Please refer to Figure 3 , Figure 3 The principle block diagram of a device for optimizing the parameters of a small reactance connected in series with the neutral point of an autotransformer provided in an embodiment of the present application, the device comprising:

[0065] The parameter information module 310 is used to obtain parameter information of the topology of the power system and the substation, the reactance of the generator, and the type and size of the load;

[0066] A current calculation module 320 is used to calculate the single-phase short-circuit current and the three-phase short-circuit current of the medium-voltage side bus according to the parameter information;

[0067] The impedance optimization module 330 is used to determine whether there is a situation where the single-phase short-circuit current is greater than the three-phase short-circuit current. If so, the single-phase short-circuit current is suppressed by connecting a small reactance in series with the neutral point of the autotransformer;

[0068] Among them, the impedance value determination process of the series small reactance is as follows: construct a first sub-objective function with the sum of the single-phase short-circuit current of the medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and manufacturing cost of the series small reactance as the minimum; based on the first sub-objective function and the second sub-objective function, combined with pre-configured constraints, a multi-objective particle swarm optimization model of the series small reactance is established; the particle swarm algorithm is used to solve the multi-objective particle swarm optimization model to obtain the impedance value of the neutral point series small reactance of the autotransformer.

[0069] In an optimization device for the parameters of the autotransformer neutral point series small reactance provided in an embodiment of the present invention, factors such as the global current limiting effect, neutral point insulation level and investment cost of the 500kV power system are comprehensively considered, and the investment cost can be reduced while ensuring the current limiting capability. Compared with the traditional autotransformer neutral point small reactance selection method, it can better solve the problem of balancing current limiting and investment cost, and can provide guidance and reference for the parameter selection of the autotransformer series small reactance in the 500kV power system.

[0070] In some embodiments, the expression of the second sub-objective function is:

[0071] Where P(j) is the control variable, P∈{0,1}, 0 means no small reactor is installed at the neutral point of the j-th autotransformer, and 1 means a small reactor is installed at the neutral point of the j-th autotransformer; k 1 and k 2 are the installation cost coefficient and manufacturing cost coefficient of the series small reactor respectively; x T (j) represents the impedance value of the small reactance connected in series with the neutral point of the jth autotransformer, f 2 Represents the second sub-objective function.

[0072] In some embodiments, the constraint conditions include a single-phase short-circuit current constraint of a busbar on the medium-voltage side of an autotransformer, an impedance value constraint of a series-connected small reactance, and an insulation level constraint of a neutral point of the autotransformer.

[0073] In some embodiments, the expression of the insulation level constraint is:

[0074] Among them, U 0L is the effective value of the lightning impulse withstand voltage at the neutral point of the transformer; α is the line capacitance coefficient; γ is the transformer oscillation coefficient, U ph is the effective value of the maximum phase voltage in the power system operation, and K is the grounding coefficient.

[0075] In some embodiments, the device further includes: a parameter optimization module for adjusting the weight parameters of the particle swarm algorithm using a dynamic inertia factor.

[0076] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for optimizing the parameters of a small reactance connected in series with the neutral point of an autotransformer, characterized in that: Methods include: Obtain parameter information on the topology of the power system and substation, generator reactance, load type and size; Calculate the single-phase short-circuit current and three-phase short-circuit current of the medium-voltage side bus according to the parameter information; Determine whether there is a situation where the single-phase short-circuit current is greater than the three-phase short-circuit current. If so, suppress the single-phase short-circuit current by connecting a small reactance in series with the neutral point of the autotransformer; Among them, the impedance value determination process of the series small reactance is as follows: construct a first sub-objective function with the sum of the single-phase short-circuit current of the medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and manufacturing cost of the series small reactance as the minimum; based on the first sub-objective function and the second sub-objective function, combined with pre-configured constraints, a multi-objective particle swarm optimization model of the series small reactance is established; the particle swarm algorithm is used to solve the multi-objective particle swarm optimization model to obtain the impedance value of the neutral point series small reactance of the autotransformer.

2. The method according to claim 1, characterized in that The expression of the second sub-objective function is: Where P(j) is the control variable, P∈{0,1}, 0 means no small reactor is installed at the neutral point of the j-th autotransformer, and 1 means a small reactor is installed at the neutral point of the j-th autotransformer; k1 and k2 are the installation cost coefficient and manufacturing cost coefficient of the series small reactor respectively; x T (j) represents the impedance value of the small reactance connected in series with the neutral point of the j-th autotransformer, and f2 represents the second sub-objective function.

3. The method according to claim 1, characterized in that The constraint conditions include the single-phase short-circuit current constraint of the busbar on the medium-voltage side of the autotransformer, the impedance value constraint of the series-connected small reactance, and the insulation level constraint of the neutral point of the autotransformer.

4. The method according to claim 3, characterized in that: The expression of the insulation level constraint is: Among them, U 0L is the effective value of the lightning impulse withstand voltage at the neutral point of the transformer; α is the line capacitance coefficient; γ is the transformer oscillation coefficient, U ph is the effective value of the maximum phase voltage in the power system operation, and K is the grounding coefficient.

5. The method according to claim 1, characterized in that Before using the particle swarm algorithm to solve the multi-objective particle swarm optimization model, the method further includes: using a dynamic inertia factor to adjust a weight parameter of the particle swarm algorithm.

6. An optimization device for the parameters of a small reactance connected in series with the neutral point of an autotransformer, characterized in that: The device includes: Parameter information module, used to obtain parameter information of the power system and substation topology, generator reactance, load type and size; A current calculation module is used to calculate the single-phase short-circuit current and three-phase short-circuit current of the medium-voltage side bus according to parameter information; The impedance optimization module is used to determine whether there is a situation where the single-phase short-circuit current is greater than the three-phase short-circuit current. If so, the single-phase short-circuit current is suppressed by connecting a small reactance in series at the neutral point of the autotransformer; Among them, the impedance value determination process of the series small reactance is as follows: construct a first sub-objective function with the sum of the single-phase short-circuit current of the medium-voltage side bus as the minimum and a second sub-objective function with the installation cost and manufacturing cost of the series small reactance as the minimum; based on the first sub-objective function and the second sub-objective function, combined with pre-configured constraints, a multi-objective particle swarm optimization model of the series small reactance is established; the particle swarm algorithm is used to solve the multi-objective particle swarm optimization model to obtain the impedance value of the neutral point series small reactance of the autotransformer.

7. The device according to claim 6, characterized in that The expression of the second sub-objective function is: Where P(j) is the control variable, P∈{0,1}, 0 means no small reactor is installed at the neutral point of the j-th autotransformer, and 1 means a small reactor is installed at the neutral point of the j-th autotransformer; k1 and k2 are the installation cost coefficient and manufacturing cost coefficient of the series small reactor respectively; x T (j) represents the impedance value of the small reactance connected in series with the neutral point of the j-th autotransformer, and f2 represents the second sub-objective function.

8. The device according to claim 6, characterized in that The constraint conditions include the single-phase short-circuit current constraint of the busbar on the medium-voltage side of the autotransformer, the impedance value constraint of the series-connected small reactance, and the insulation level constraint of the neutral point of the autotransformer.

9. The device according to claim 8, characterized in that The expression of the insulation level constraint is: Among them, U 0L is the effective value of the lightning impulse withstand voltage at the neutral point of the transformer; α is the line capacitance coefficient; γ is the transformer oscillation coefficient, U ph is the effective value of the maximum phase voltage in the power system operation, and K is the grounding coefficient.

10. The device according to claim 6, characterized in that The device also includes: a parameter optimization module, which is used to adjust the weight parameters of the particle swarm algorithm by using a dynamic inertia factor.

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