CN-115579881-B - Global optimization configuration method and system for neutral point capacitance blocking device of transformer

CN115579881BCN 115579881 BCN115579881 BCN 115579881BCN-115579881-B

Abstract

The invention discloses a global optimal configuration method and a global optimal configuration system for a transformer neutral point capacitance blocking device, wherein the method comprises the steps of constructing an equivalent field coupling model, and initializing original bias current distribution of a power grid based on the equivalent field coupling model; based on the equivalent electrical distance of the equivalent impedance between the grid nodes, introducing the full-grid current unbalance as an evaluation index of the full-grid current balance, and establishing a capacitance full-grid current distribution balance game model taking the configuration of the grid direct-blocking device and the full-grid current distribution balance as the optimal configuration of the capacitance direct-blocking device of a game participant; and solving and optimizing the optimal configuration balanced game model by adopting a multi-target discrete particle swarm optimization algorithm to obtain an optimal configuration scheme of the capacitance blocking device of the power grid in the grounding very near region. The invention takes the power grid planning information into consideration, and performs the optimal configuration of the capacitance blocking device from the global angle.

Inventors

ZENG WENHUI
YANG DAN
JIAO YIFEI
FAN RONGQUAN
LUO YI
WANG HANYU
ZOU BIN
DU SIYING
YI LI
LI CHUNMEI
LI YU

Assignees

国网四川省电力公司经济技术研究院

Dates

Publication Date: 20260508
Application Date: 20221031

Claims (9)

1. The global optimal configuration method for the neutral point capacitance blocking device of the transformer is characterized by comprising the following steps of: Constructing an equivalent field coupling model, and initializing original bias current distribution of a power grid based on the equivalent field coupling model; Based on the equivalent electrical distance of the equivalent impedance between the grid nodes, introducing the full-grid current unbalance as an evaluation index of the full-grid current balance, and establishing a capacitance full-grid current distribution balance game model taking the configuration of the grid direct-blocking device and the full-grid current distribution balance as the optimal configuration of the capacitance direct-blocking device of a game participant; Solving and optimizing the optimal configuration balance game model by adopting a multi-target discrete particle swarm optimization algorithm to obtain an optimal configuration scheme of the capacitance blocking device of the power grid in the grounding very near region, wherein the evaluation index of the current balance of the whole grid Expressed as: ; ; in the formula, The number of the site is indicated and, The number of sites is represented and, Represent the first The current flowing through the neutral point of the station transformer, Represents the equivalent electric distance of the ground net rack between the ith station and the grounding electrode, is used for measuring the magnitude of the coupling degree of the bias current amplitude variation of the node and the grounding electrode in the system, Indicating the number of transformers at the ith station, And Respectively represent the self-impedance of the two grounding electrodes, Representing the transimpedance of the two ground poles, Representing the self-impedance of the ith station, And Representing the mutual impedance of the ith station and the two grounding poles respectively, The tangent value indicating the included angle formed between the ith station and the two grounding poles.
2. The global optimal configuration method for the neutral point capacitance blocking device of the transformer according to claim 1, wherein the global optimal configuration method for the neutral point capacitance blocking device of the transformer is characterized in that a grid blocking device configuration and a global current distribution balancing are established as a game participant based on Position-Nash balancing of team maximum balancing by taking the global current balancing and the minimum number of the capacitance blocking devices as optimization targets.
3. The global optimal configuration method for the transformer neutral point capacitance blocking device according to claim 1, wherein the optimal configuration balanced game model is solved and optimized by adopting a multi-objective ion particle swarm optimization algorithm, and the method specifically comprises the following steps: Calculating to obtain neutral point direct current matrixes under all strategies to obtain the configuration quantity and current balance coefficient of the blocking devices under all strategies; introducing a dynamic inertia weight adjustment strategy based on the position similarity, and dynamically calculating the inertia weight of the particles after iteration according to the position similarity between the current particle vector and the optimal particle vector every iteration; Recording the inertia weight and the evaluation index value of each iteration; And introducing a position similarity particle position updating strategy based on a random correction coefficient to enable particles to approach to the position of the optimal particles, updating and correcting the particles which do not meet the constraint conditions for the second time, and storing the particles which meet the constraint conditions after the first time updating, and recording the calculation result of the T+1th time if the calculation result of the evaluation index value of the T+1th time is superior to the calculation result of the T time.
4. The global optimal configuration method for the transformer neutral point capacitance blocking device according to claim 3, wherein the dynamic inertia weight adjustment strategy based on the position similarity is specifically as follows: ; ; in the formula, The degree of similarity is indicated and, Representing the current kth iteration particle vector, For the optimal particle vector to be present, Representing the inertial weight of particle i at the kth iteration, And Respectively represent the upper and lower limits of the inertia weight when The larger the value, the higher the similarity between particles, the more the particle is close to the optimal particle of the population when the similarity is larger than a preset value, the inertia weight should be reduced, and the more the particle is far from the optimal particle of the population when the similarity is smaller than the preset value, the inertia weight should be increased.
5. The global optimal configuration method for the transformer neutral point capacitance blocking device according to claim 4, wherein the position similarity particle position updating strategy based on the random correction coefficient is specifically as follows: ; ; in the formula, Represents the position of particle i after the kth iteration, D represents a random position correction coefficient, Representing the maximum number of iterations.
6. The global optimal configuration method of the transformer neutral point capacitance blocking device according to any one of claims 1 to 5, wherein an equivalent field path coupling model is built, and the original bias current distribution of the power grid is initialized based on the equivalent field path coupling model, specifically: And establishing an equivalent field path coupling model according to the power grid line topology, the grounding electrode characteristics, the physical parameters and the regional soil characteristics, and calculating to obtain a full-network current distribution initialization value after adding a capacitance blocking device to the neutral point of the overrunning transformer based on the equivalent field path coupling model.
7. A global optimal configuration system for a transformer neutral point capacitance blocking device is characterized by comprising the following components: The initialization module is used for building an equivalent field coupling model and initializing the original magnetic bias current distribution of the power grid based on the equivalent field coupling model; The game model construction module is used for introducing the full-network current unbalance degree as an evaluation index of full-network current balance based on the equivalent electrical distance of the equivalent impedance between the nodes, and establishing a capacitance straight blocking device optimization configuration balanced game model taking the configuration of the power grid straight blocking device and the full-network current distribution balance as game participants; The solving and optimizing module adopts a multi-target discrete particle swarm optimization algorithm to solve and optimize the optimal configuration balanced game model to obtain an optimal configuration scheme of the capacitance blocking device of the power grid in the grounding very near region; The evaluation index of the whole network current balance Expressed as: ; ; in the formula, The number of the site is indicated and, The number of sites is represented and, Represent the first The current flowing through the neutral point of the station transformer, Represents the equivalent electric distance of the ground net rack between the ith station and the grounding electrode, is used for measuring the magnitude of the coupling degree of the bias current amplitude variation of the node and the grounding electrode in the system, Indicating the number of transformers at the ith station, And Respectively represent the self-impedance of the two grounding electrodes, Representing the transimpedance of the two ground poles, Representing the self-impedance of the ith station, And Representing the mutual impedance of the ith station and the two grounding poles respectively, The tangent value indicating the included angle formed between the ith station and the two grounding poles.
8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1-6 when the computer program is executed.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method according to any of claims 1-6.

Description

Global optimization configuration method and system for neutral point capacitance blocking device of transformer Technical Field The invention relates to the technical field of high-voltage direct-current transmission, in particular to a global optimal configuration method and system for a neutral point capacitance blocking device of a transformer. Background Along with the increasing maturity of the high-voltage direct-current transmission technology, the application range is gradually widened, and the influence caused by the direct-current magnetic bias problem is also more and more obvious. When the direct current transmission system adopts a monopole ground loop operation mode, a direct current circuit and the ground form a loop, the direct current ground current is equal to the system operation current on the direct current circuit, and the ground current causes unbalanced ground potential in a large range. When the excessive direct current magnetic bias current invades the transformer winding through the neutral point, a series of adverse consequences of damage to the transformer state, such as aggravation of transformer vibration, occurrence of harmonic wave, increase of noise, overheat of oil temperature, increase of measurement error and the like, are caused, and the adverse effects on safe and stable operation of a power grid and even surrounding environments are caused. The current DC suppression method for the transformer monomer is mature, and can be roughly divided into a series small resistance method, a reverse current compensation method and a neutral point series capacitance method. The neutral point series capacitance method has the optimal inhibition effect, so that the application range of the neutral point series capacitance method is the widest. The method for in-situ treatment is not suitable for the problems caused by direct current magnetic bias at present only when the direct current magnetic bias current exceeds the standard, and the neutral point direct current exceeding condition of other transformers can be caused by the fact that the principle of 'out-of-limit installation' is maintained. At present, the optimal configuration method of the transformer blocking device can be roughly divided into two types. The first type mainly adopts an intelligent optimization algorithm to optimize the capacitance blocking configuration of the input power grid or to optimize the mixed configuration of the novel uniform-direct device and the blocking device. The method does not usually consider planning information of the power grid topology, and the problems that the calculation of the DC current of the neutral point of the transformer is inaccurate, the algorithm is easy to be trapped in local convergence and the like can occur. The second type is mainly to identify bias current key sites in the whole network by utilizing the connectivity of the power grid, but the method is difficult to carry out global optimal configuration on the power grid blocking device. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a global optimal configuration method and a global optimal configuration system for a neutral point capacitance blocking device of a transformer. The invention takes the power grid planning information into consideration, and performs the optimal configuration of the capacitance blocking device from the global angle. The invention is realized by the following technical scheme: a global optimization configuration method for a transformer neutral point capacitance blocking device comprises the following steps: Constructing an equivalent field coupling model, and initializing original bias current distribution of a power grid based on the equivalent field coupling model; Based on the equivalent electrical distance of the equivalent impedance between the grid nodes, introducing the full-grid current unbalance as an evaluation index of the full-grid current balance, and establishing a capacitance full-grid current distribution balance game model taking the configuration of the grid direct-blocking device and the full-grid current distribution balance as the optimal configuration of the capacitance direct-blocking device of a game participant; And solving and optimizing the optimal configuration balanced game model by adopting a multi-target discrete particle swarm optimization algorithm to obtain an optimal configuration scheme of the capacitance blocking device of the power grid in the grounding very near region. As a preferred embodiment, the evaluation index epsilon of the current balance of the whole network of the present invention is expressed as: Li＝(1-tanθi)2zpp+tanθi2zqq-2(tanθi2-tanθi)zpq+zii-2(1-tanθi)zip-2tanθiziq Wherein I represents the number of stations, N represents the number of stations, I i represents the current flowing through the neutral point of the transformer of the ith station, L i represents the equivalent electrical distance