A distribution network voltage control method and system

Abstract

The present invention proposes a distribution network voltage control method and system, which calculates the electrical distance between the first nodes, establishes an electrical relationship matrix, and then performs node cluster division to obtain the second node; the second node is optimized for reactive power according to the sparrow search algorithm, and the third node is screened out, and it is determined whether the voltage of the third node exceeds the limit, if not, the process ends; if so, the third node is optimized for active power, and the fourth node is screened out, and the target distribution network is controlled according to the active power and reactive power of the fourth node. The present invention can solve the problem that the existing technology has a large amount of calculation and a complex calculation model, which affects the operational stability of photovoltaic grid-connected. By adopting cluster division, the number of nodes is reduced, the system complexity is reduced, and the distribution network is controlled by dual power regulation and scene-based regulation, which can effectively improve the system control efficiency and thus ensure the stable operation of the power system.

Description

Technical Field

[0001] The present invention relates to the field of distributed photovoltaic technology, and in particular to a distribution network voltage control method and system. Background Art

[0002] The rise of photovoltaic research and technology applications has set off an energy revolution. Distributed photovoltaic installed capacity has repeatedly set new records. All aspects of the power system have ushered in challenges, and the traditional power system is transitioning to a new power system. However, large-scale distributed photovoltaic installations have brought risks and challenges to the distribution network. Photovoltaic power generation is affected by sunlight conditions, has no rotational inertia, and power surges and declines often occur, affecting the safe and stable operation of the distribution network. Therefore, how to control voltage on the distribution network of large-scale distributed photovoltaic grid-connected is a current research hotspot.

[0003] The existing technology considers a large number of nodes when performing voltage control calculations in large-scale distributed photovoltaic grid-connected situations, which makes the calculation model more complicated and time-consuming, thereby affecting the stable performance of photovoltaic grid-connected systems during operation. Summary of the invention

[0004] Based on the above problems, the present invention proposes a distribution network voltage control method and system, which can improve the stability performance of distributed photovoltaic power grid.

[0005] To achieve the above object, an embodiment of the present invention provides a method for controlling voltage in a power distribution network, comprising:

[0006] Obtaining grid parameters of a plurality of first nodes in a target distribution network within a time period to be analyzed;

[0007] Determine the electrical distance between the first nodes according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then establish an electrical relationship matrix according to the electrical distance between the first nodes;

[0008] According to the electrical relationship matrix and the preset community discovery algorithm, the plurality of first nodes are clustered and the clusters are compressed to obtain a plurality of second nodes and the reactive power of each second node is determined;

[0009] The reactive power of the plurality of second nodes is optimized by using a preset sparrow search algorithm, a plurality of third nodes are screened out, and grid parameters of the plurality of third nodes in the target distribution network to be analyzed are determined;

[0010] Determining the voltage of each third node according to the grid parameters of the plurality of third nodes and the preset power flow algorithm;

[0011] Determining whether the voltage of each third node exceeds a preset voltage limit value;

[0012] When it is determined that the voltage of each third node exceeds the preset voltage limit value, the preset sparrow search algorithm is used to perform active power optimization on the active power of the plurality of third nodes, a plurality of fourth nodes are screened out, and the reactive power and active power of the plurality of fourth nodes are determined;

[0013] The photovoltaic value of the target distribution network is determined, and the operating voltage of the target distribution network is controlled through the reactive power and the active power of the plurality of fourth nodes.

[0014] A distribution network voltage control method proposed in an embodiment of the present invention reduces the number of nodes and the system complexity by adopting cluster division, optimizes the active power and reactive power of the cluster through the sparrow algorithm, and controls the distribution network according to the optimization result by adopting dual power regulation and scenario-based regulation, which can effectively improve the system control efficiency and thus ensure the stable operation of the power system.

[0015] Furthermore, the electrical distances between the first nodes are determined according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then an electrical relationship matrix is ​​established according to the electrical distances between the first nodes, specifically:

[0016] According to the grid parameters of the plurality of first nodes, flow calculation is performed on the target distribution network in a time section to obtain the plurality of first node voltages, the plurality of first node active powers and the plurality of first node reactive powers; wherein the time section is a measurement time interval within the time to be analyzed;

[0017] According to the plurality of first node voltages, the plurality of first node active powers and the plurality of first node reactive powers, taking quotients to obtain a plurality of first node active voltage sensitivities and a plurality of first node reactive voltage sensitivities, and averaging them to obtain a plurality of first node power voltage sensitivities;

[0018] According to the power voltage sensitivities of the multiple first nodes, the electrical distances between the first nodes are calculated, and the electrical distances are normalized to obtain normalized results, and the electrical relationship matrix is ​​established, wherein the normalized results are elements of the electrical relationship matrix.

[0019] Furthermore, according to the electrical relationship matrix and the preset community discovery algorithm, the plurality of first nodes are clustered and the clusters after the division are compressed to obtain the plurality of second nodes and determine the reactive power of each second node, specifically:

[0020] Allocating adjacent clusters to the plurality of first nodes according to the elements of the electrical relationship matrix, and calculating a change in modularity before and after the allocation;

[0021] When it is determined that the modularity change of the multiple first nodes is less than a preset limit, it is determined that the cluster structure no longer changes, the cluster divided from the multiple first nodes is compressed into multiple second nodes, and the reactive power of each second node is determined.

[0022] Further, the reactive power of the plurality of second nodes is optimized by using a preset sparrow search algorithm, a plurality of third nodes are screened out, and the grid parameters of the plurality of third nodes in the target distribution network to be analyzed are determined, specifically:

[0023] The reactive power of the second nodes is optimized in turn with the goal of minimizing the sum of the active power losses of each branch in the cluster, and the multiple second nodes that meet the reactive power optimization conditions are screened out to form the multiple third nodes, and the grid parameters of the multiple third nodes in the target distribution network to be analyzed are determined.

[0024] Further, the determining of each third node voltage according to the grid parameters of the plurality of third nodes and the preset power flow algorithm; and judging whether the voltage of each third node exceeds a preset voltage limit value according to the voltage of each third node are specifically as follows:

[0025] Performing power flow calculation based on the grid parameters of the plurality of third nodes to obtain the voltage of the third node;

[0026] According to the voltages of each third node and the preset voltage limit value, determining whether the preset voltage limit value is exceeded, wherein the preset voltage limit value includes: a medium voltage upper limit threshold, a medium voltage lower limit threshold, a low voltage upper limit threshold and a low voltage lower limit threshold;

[0027] When it is determined that the medium voltage region voltage of each third node is greater than the medium voltage upper limit threshold, or less than the medium voltage lower limit threshold, it is called exceeding the preset voltage limit value. When it is determined that the low voltage region voltage of each third node is greater than the low voltage upper limit threshold, or less than the low voltage lower limit threshold, it is called exceeding the preset voltage limit value.

[0028] Further, when it is determined that the voltage of each third node exceeds the preset voltage limit value, the preset sparrow search algorithm is used to perform active power optimization on the active power of the multiple third nodes, multiple fourth nodes are screened out, and the reactive power and active power of the multiple fourth nodes are determined, specifically:

[0029] When it is determined that the voltage of the third node exceeds the preset voltage limit value, the active power parameters of the third nodes are optimized with the goal of minimizing the sum of the active losses of each branch in the cluster, and multiple fourth nodes that meet the active power optimization conditions are screened out, and the reactive power and active power of the multiple fourth nodes are determined.

[0030] Further, the photovoltaic value of the target distribution network is determined, and the operating voltage of the target distribution network is controlled through the reactive power and active power of the plurality of fourth nodes, specifically:

[0031] For a scenario where the photovoltaic amount is less than a preset photovoltaic value, the target distribution network operating voltage value is controlled by reactive power regulation of the plurality of fourth nodes;

[0032] For a scenario where the photovoltaic amount is greater than or equal to the preset photovoltaic value, the target distribution network operating voltage value is jointly adjusted and controlled by the reactive power and active power of the multiple fourth nodes.

[0033] The embodiment of the present invention also provides a distribution network voltage control system, including: a parameter acquisition module, an electrical relationship matrix building module, a cluster dynamic division module, a reactive power optimization module, a voltage over-limit judgment module, an active power optimization module and a power grid control module;

[0034] The parameter acquisition module is used to obtain the power grid parameters of multiple first nodes in the target distribution network within the time period to be analyzed;

[0035] The electrical relationship matrix building module is used to determine the electrical distance between each first node according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then establish an electrical relationship matrix according to the electrical distance between each first node;

[0036] The cluster dynamic division module is used to divide the multiple first nodes into clusters according to the electrical relationship matrix and the preset community discovery algorithm, and compress the divided clusters to obtain multiple second nodes and determine the reactive power of each second node;

[0037] The reactive power optimization module is used to optimize the reactive power of the plurality of second nodes by using a preset sparrow search algorithm, screen out a plurality of third nodes, and determine the grid parameters of the plurality of third nodes within the time period to be analyzed of the target distribution network;

[0038] The voltage over-limit judgment module is used to determine the voltage of each third node according to the grid parameters of the plurality of third nodes and the preset power flow algorithm; and judge whether the voltage of each third node exceeds the preset voltage limit value according to the voltage of each third node;

[0039] The active power optimization module is used to, when it is determined that the voltage of each third node exceeds the preset voltage limit value, perform active power optimization on the active power of the plurality of third nodes using the preset sparrow search algorithm, screen out a plurality of fourth nodes, and determine the reactive power and active power of the plurality of fourth nodes;

[0040] The power grid control module is used to determine the photovoltaic value of the target power distribution network, and control the operating voltage of the target power distribution network through the reactive power and active power of the multiple fourth nodes.

[0041] A distribution network voltage control system provided by an embodiment of the present invention can reduce the number of nodes that need to be calculated step by step by screening nodes, thereby improving the working efficiency and stability of the power grid. At the same time, by adjusting the power grid voltage in a dual-function manner, the stable operation of the power system can be effectively guaranteed.

[0042] Furthermore, the electrical relationship matrix building module is used to determine the electrical distance between each first node according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then establish an electrical relationship matrix according to the electrical distance between each first node, and further includes:

[0043] Parameter collection unit, first power flow calculation unit and matrix establishment unit;

[0044] The parameter acquisition unit is used to read the power grid parameters of the multiple first nodes;

[0045] The first power flow calculation unit is used to perform power flow calculation on the target distribution network in a time section to obtain the multiple first node voltages, multiple first node active powers and multiple first node reactive powers; wherein the time section is a measurement time interval within the time to be analyzed; according to the multiple first node voltages, the multiple first node active powers and the multiple first node reactive powers, multiple first node active voltage sensitivities and multiple first node reactive voltage sensitivities are obtained by taking the quotient, and multiple first node power voltage sensitivities are obtained by averaging;

[0046] The matrix establishment unit is used to calculate the electrical distance between the first nodes according to the power voltage sensitivities of the multiple first nodes, perform electrical distance normalization processing, obtain normalized results, and establish the electrical relationship matrix, wherein the normalized results are elements of the electrical relationship matrix.

[0047] Further, the cluster dynamic division module is used to dynamically divide the first node into clusters according to the electrical relationship matrix through a community discovery algorithm to obtain a second node, wherein the second node is obtained by compressing the cluster assigned to the first node, and further includes:

[0048] Matrix calculation allocation unit and node compression unit;

[0049] The matrix calculation allocation unit is used to allocate adjacent clusters to the plurality of first nodes according to the elements of the electrical relationship matrix, and calculate the change in modularity before and after the allocation;

[0050] The node compression unit is used to determine that the cluster structure no longer changes after determining that the modularity change of the multiple first nodes is less than a preset limit, compress the cluster divided from the multiple first nodes into multiple second nodes, and determine the reactive power of each second node.

[0051] Further, the reactive power optimization module is used to optimize the reactive power parameters of the second node according to the second node through the sparrow search algorithm to obtain the reactive power optimization result, and the second node that meets the reactive power optimization result condition is formed into a third node, and also includes:

[0052] The first sparrow search unit and the reactive power optimization result output unit;

[0053] The first sparrow search unit is used to sequentially optimize the reactive power parameters of the second node with the goal of minimizing the sum of active power losses of each branch in the cluster;

[0054] The reactive power optimization result output unit is used to screen out the multiple second nodes that meet the reactive power optimization conditions to form the multiple third nodes, and determine the grid parameters of the multiple third nodes within the target distribution network to be analyzed time period.

[0055] Further, the voltage over-limit judgment module is used to determine the voltage of each third node according to the grid parameters of the plurality of third nodes and the preset power flow algorithm; and judge whether the voltage of each third node exceeds the preset voltage limit value according to the voltage of each third node, and further includes:

[0056] A second power flow calculation unit and a node voltage determination unit;

[0057] The second power flow calculation unit is used to perform power flow calculation based on the power grid parameters of the plurality of third nodes to obtain the third node voltage;

[0058] The node voltage judgment unit is used to judge whether the preset voltage limit value is exceeded according to the voltage of each third node and the preset voltage limit value, wherein the preset voltage limit value includes: a medium voltage upper limit threshold, a medium voltage lower limit threshold, a low voltage upper limit threshold and a low voltage lower limit threshold; when it is determined that the medium voltage area voltage of each third node is greater than the medium voltage upper limit threshold, or less than the medium voltage lower limit threshold, it is called exceeding the preset voltage limit value. When it is determined that the low voltage area voltage of each third node is greater than the low voltage upper limit threshold, or less than the low voltage lower limit threshold, it is called exceeding the preset voltage limit value.

[0059] Further, the active power optimization module is used to obtain a third node voltage through power flow calculation according to the reactive power optimization result; determine whether it exceeds a preset voltage limit value according to the third node voltage; when it is determined that the third node voltage does not exceed the preset voltage limit value, perform active power optimization on the second node through a sparrow search algorithm to obtain an active power optimization result, and also includes:

[0060] A second sparrow search unit and an active power optimization result output unit;

[0061] The second sparrow search unit is used for, when it is determined that the voltage of the third node exceeds the preset voltage limit value, sequentially optimizing the active power parameters of the third nodes with the goal of minimizing the sum of active power losses of each branch in the cluster;

[0062] The active power optimization result output unit is used to screen out multiple fourth nodes that meet the active power optimization conditions, and determine the reactive power and active power of the multiple fourth nodes.

[0063] Further, the power grid control module is used to determine the photovoltaic value of the target distribution network and control the operating voltage of the target distribution network according to the reactive power optimization result and the active power optimization result, and also includes:

[0064] Photovoltaic quantity judgment unit and voltage control unit;

[0065] The photovoltaic quantity judgment unit is used to determine whether the photovoltaic quantity value of the target distribution network exceeds the preset photovoltaic value;

[0066] The voltage control unit is used to control the target distribution network operating voltage value through reactive power regulation of the plurality of fourth nodes in a scenario where the photovoltaic amount is less than the preset photovoltaic value;

[0067] For a scenario where the photovoltaic amount is greater than or equal to the preset photovoltaic value, the target distribution network operating voltage value is jointly adjusted and controlled by the reactive power and active power of the multiple fourth nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 A schematic diagram of a flow chart of a method for controlling voltage in a power distribution network provided in an embodiment of the present invention;

[0069] Figure 2 A schematic diagram of the structure of a power distribution network voltage control system provided by a certain embodiment of the present invention;

[0070] Figure 3 A schematic diagram of a module structure of an electrical relationship matrix of a power distribution network voltage control system provided by an embodiment of the present invention;

[0071] Figure 4 A schematic diagram of a cluster dynamic division module structure of a distribution network voltage control system provided by an embodiment of the present invention;

[0072] Figure 5 A schematic diagram of the structure of a reactive power optimization module of a distribution network voltage control system provided by a certain embodiment of the present invention;

[0073] Figure 6 A schematic diagram of the structure of a voltage over-limit judgment module of a power distribution network voltage control system provided by an embodiment of the present invention;

[0074] Figure 7 A schematic diagram of the structure of an active power optimization module of a distribution network voltage control system provided by a certain embodiment of the present invention;

[0075] Figure 8 A schematic diagram of the structure of a power grid control module of a power distribution network voltage control system provided by an embodiment of the present invention;

[0076] Fig. 9 A schematic flow chart of a sparrow search algorithm for a distribution network voltage control method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0078] Example 1

[0079] See also Figure 1 , Figure 1 The following is a flow chart of a method for controlling voltage in a power distribution network provided by an embodiment of the present invention. Figure 1 As shown, the present invention proposes a distribution network voltage control method, including steps 101 to 108, each step is specifically as follows:

[0080] Step 101: Obtain grid parameters of a plurality of first nodes in a target distribution network within a time period to be analyzed.

[0081] As an example of this embodiment, the electrical parameters of the target distribution network G within the time range T to be analyzed are obtained, specifically, the conductor parameters, topology parameters, and distribution transformer parameters are obtained. The conductor parameters include the resistance, reactance, and capacitance parameters of the overhead conductors, cables, load switches, circuit breakers, and other connecting components in the distribution line; the topology parameters include the names of the nodes in the distribution line, and the names of the connecting components such as the overhead conductors, cables, load switches, circuit breakers, and distribution transformers connected to the nodes; the distribution transformer parameters include gears, copper losses, and iron losses.

[0082] Step 102, determining the electrical distance between each first node according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then establishing an electrical relationship matrix according to the electrical distance between each first node.

[0083] As an example of this embodiment, according to the grid parameters of the multiple first nodes, the target distribution network G is subjected to power flow calculation on a time section, wherein the power flow calculation algorithm includes but is not limited to the forward-backward method, the Newton-Raphson method, the Gauss-Seidel iteration method, etc., to obtain the multiple first node voltages, the multiple first node active powers, and the multiple first node reactive powers; wherein the time section n t is the measurement time interval gap within the time to be analyzed T, specifically:

[0084] According to the plurality of first node voltages, the plurality of first node active powers and the plurality of first node reactive powers, a plurality of first node active voltage sensitivities are obtained by taking a quotient:

[0085]

[0086] Multiple first node reactive voltage sensitivity:

[0087]

[0088] The power and voltage sensitivities of multiple first nodes are obtained by averaging:

[0089]

[0090] in, and Represents the active / reactive voltage sensitivity between nodes i and j. Its physical meaning is the impact of injecting unit active / reactive power into the node on the change of node voltage amplitude.

[0091] According to the plurality of first node power voltage sensitivities Calculate the electrical distance d between the first nodes ij :

[0092]

[0093] Where i is the row number, j is the column number, and the electrical distance is normalized to obtain the normalized result e ij :

[0094]

[0095] Among them, d max and d min are the maximum and minimum values ​​of the electrical distance in the distribution network, respectively.

[0096] And build n i ×n j The electrical relationship matrix, wherein the normalized result e ij is the element of the electrical relationship matrix.

[0097] Step 103 : According to the electrical relationship matrix and a preset community discovery algorithm, the plurality of first nodes are clustered and the clusters are compressed to obtain a plurality of second nodes and determine the reactive power of each second node.

[0098] As an example of this embodiment, according to the element e of the electrical relationship matrix ij , perform adjacent cluster allocation for the multiple first nodes: regard the multiple first nodes in the target distribution network G as independent clusters, and allocate them to all their adjacent clusters in turn, and calculate the modularity change before and after the allocation:

[0099]

[0100] in, k i =∑ j e ij , when node i and node j belong to the same community, δ(i,j)=1, otherwise δ(i,j)=0.

[0101] Find the adjacent cluster corresponding to the maximum value of the modularity change. If the value is greater than the preset limit, assign the node to this cluster. When it is determined that the modularity change of the multiple first nodes is less than the preset limit, it is determined that the cluster structure does not change, and the clusters after the multiple first nodes are divided are compressed into multiple second nodes:

[0102] G 1 , G 2 , …, G M

[0103] Wherein, M is the number of clusters after the first nodes are divided. The weights of the edges within the cluster are converted into the weights of each second node, the weights of the edges between clusters are converted into the weights of the edges between the second nodes, and the reactive power of each second node is determined, wherein the weights include: electrical parameters, load parameters and distributed photovoltaic parameters.

[0104] The present invention adopts dynamic cluster division based on community discovery algorithm, and can make optimal arrangement for the number and results of cluster division according to the electrical parameters and distributed photovoltaic parameters of the target distribution network G, without giving the number of clusters in advance, so the application is smarter and the effect is better.

[0105] Step 104 , optimizing the reactive power of the plurality of second nodes by using a preset sparrow search algorithm, screening out a plurality of third nodes, and determining grid parameters of the plurality of third nodes within the target distribution network to be analyzed time period.

[0106] As an example of this embodiment, the reactive power of the second node is sequentially optimized with the goal of minimizing the sum of active power losses of each branch in the cluster:

[0107]

[0108] The plurality of second nodes satisfying the reactive power optimization condition are screened out to form the plurality of third nodes, and grid parameters of the plurality of third nodes within the time period to be analyzed in the target power distribution network are determined.

[0109] Step 105 : determining the voltage of each third node according to the grid parameters of the plurality of third nodes and the preset power flow algorithm.

[0110] As an example of this embodiment, the power grid parameters of the multiple third nodes are used to perform flow calculations to obtain the third node voltages. Specifically, the reactive power parameters of the multiple third nodes are used as the reactive power part of the updated distributed photovoltaic parameters of the target distribution network G within the time range T to be analyzed, and power flow calculations are performed to obtain the voltage, current, active power and reactive power of each third node, and to determine whether there is a voltage over-limit at each node.

[0111] Step 106 , determining whether the voltages of the third nodes exceed a preset voltage limit value according to the voltages of the third nodes.

[0112] As an example of this embodiment, according to the voltages of each third node and the preset voltage limit value, it is determined whether the preset voltage limit value is exceeded, wherein the preset voltage limit value includes: a medium voltage upper limit threshold, a medium voltage lower limit threshold, a low voltage upper limit threshold and a low voltage lower limit threshold;

[0113] When it is determined that the medium voltage region voltage of each third node is greater than the medium voltage upper limit threshold, or less than the medium voltage lower limit threshold, it is called exceeding the preset voltage limit value. When it is determined that the low voltage region voltage of each third node is greater than the low voltage upper limit threshold, or less than the low voltage lower limit threshold, it is called exceeding the preset voltage limit value.

[0114] Step 107, when it is determined that the voltage of each third node exceeds the preset voltage limit value, the preset sparrow search algorithm is used to optimize the active power of the multiple third nodes, multiple fourth nodes are screened out, and the reactive power and active power of the multiple fourth nodes are determined.

[0115] As an example of this embodiment, when it is determined that the voltage of the third node exceeds the preset voltage limit value, active power parameter optimization is performed on the third node in turn with the goal of minimizing the sum of active power losses of each branch in the cluster:

[0116]

[0117] A plurality of fourth nodes satisfying the active power optimization condition are screened out, and the reactive power and active power of the plurality of fourth nodes are determined.

[0118] As another example of this embodiment, see Fig. 9 , Fig. 9 A schematic diagram of a flow chart of a sparrow search algorithm for a distribution network voltage control method provided by a certain embodiment of the present invention. Fig. 9 As shown, the sparrow search algorithm described in step 104 and step 107 includes S1 to S7, specifically:

[0119] S1, initialize the population, divide the discoverers and joiners, and sort them according to fitness. The discoverers and joiners are specifically the reactive parameters of the second node in step 104, and the population is the reactive parameters of several groups of second nodes; in step 107, they are the active parameters of the third node, and the population is the active parameters of several groups of third nodes; the fitness is specifically the sum of the active losses of each branch in the cluster.

[0120] S2, discoverer (population leader) position update,

[0121]

[0122] Among them, X i,j represents the position information of the i-th sparrow in the j-th dimension; α∈(0,1] is a random number; R2 and ST represent the warning value and safety value respectively; Q is a random number that obeys the normal distribution; L is a 1×d all-1 matrix.

[0123] S3, joiner (follower of the discoverer, in a population, except for the discoverer, all other sparrows are defined as joiners) position update

[0124]

[0125] Among them, X P is the global optimal position occupied by the finder; is the global worst position; A represents a 1×d matrix, in which each element is randomly assigned a value of 1 or -1, A + =A T (AA T ) -1 .

[0126] S4, the position of the alerter (the sparrow that discovers danger) is updated (the alerter is randomly generated in the population and accounts for 10-20% of the population. The role of the alerter can be understood as a random variation of the algorithm)

[0127]

[0128] in, is the current global optimal position; β is the step size control parameter, which is a normally distributed random number with a mean of 0 and a variance of 1; K is a random number between -1 and 1; f i is the individual fitness value of the current sparrow; f g and f w are the current global optimal and worst fitness values ​​respectively; ε is a constant to avoid the denominator being 0.

[0129] S5, boundary condition control, the parameters involved in the algorithm optimization are mainly the reactive power parameters and active power parameters of the distributed photovoltaic nodes. Among them, the boundary of the reactive power parameter is limited by the inverter power factor value; the boundary of the active power parameter is limited by the maximum photovoltaic output value at the current moment. If the parameter overflows the boundary during the algorithm optimization process, the computer program should adjust it to the boundary value.

[0130] S6, update the population and sort it. The population is sorted from best to worst in terms of fitness. The computer program will redistribute discoverers and joiners based on this sorting.

[0131] S7, determine whether the termination condition is met. If so, end the iteration and output the result. Otherwise, repeat steps S2-S6. The termination condition is specifically: select a group of third nodes with the smallest sum of active power losses of each branch in the cluster or select a group of fourth nodes with the smallest sum of active power losses of each branch in the cluster. The termination condition can be set as follows: (1) The objective function has converged, that is, after multiple iterations, no better objective function value can be obtained; (2) The maximum number of iterations is reached, which is set by the experiment operator.

[0132] Step 108: Determine the photovoltaic value of the target distribution network, and control the operating voltage of the target distribution network through the reactive power and active power of the plurality of fourth nodes.

[0133] As an example of this embodiment, for a scenario where the photovoltaic amount is less than a preset photovoltaic value, the target distribution network operating voltage value is controlled by reactive power regulation of the multiple fourth nodes; that is, in a scenario where the photovoltaic value is small, the distribution network voltage regulation can be achieved only by reactive power regulation of the inverter.

[0134] For scenarios where the photovoltaic power is greater than or equal to the preset photovoltaic value, the reactive power and active power of the plurality of fourth nodes are used to jointly adjust and control the target distribution network operating voltage value. That is, in scenarios where the photovoltaic power value is relatively large, a small amount of abandoned light is used to achieve effective control of the distribution network voltage, thereby ensuring the stable operation of the power system.

[0135] A distribution network voltage control method proposed in an embodiment of the present invention reduces the number of nodes and the system complexity by adopting cluster division, optimizes the active power and reactive power of the cluster through the sparrow algorithm, and controls the distribution network according to the optimization result by adopting dual power regulation and scenario-based regulation, which can effectively improve the system control efficiency and thus ensure the stable operation of the power system.

[0136] Example 2

[0137] See also Figure 2 , Figure 2 The schematic diagram of a distribution network voltage control system provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the present invention proposes a distribution network voltage control system, comprising:

[0138] Parameter acquisition module 201, electrical relationship matrix building module 202, cluster dynamic division module 203, reactive power optimization module 204, voltage over-limit judgment module 205, active power optimization module 206 and power grid control module 207;

[0139] The parameter acquisition module 201 is used to obtain the power grid parameters of a plurality of first nodes in the target power distribution network within the time period to be analyzed.

[0140] The electrical relationship matrix building module 202 is used to determine the electrical distance between each first node according to the grid parameters of the multiple first nodes and a preset power flow algorithm, and then establish an electrical relationship matrix according to the electrical distance between each first node.

[0141] As an example of this embodiment, see Figure 3 , Figure 3A schematic diagram of a module structure of an electrical relationship matrix of a distribution network voltage control system provided by an embodiment of the present invention. Figure 3 As shown, an electrical relationship matrix building module provided by the present invention includes: a parameter acquisition unit 301, a first power flow calculation unit 302 and a matrix building unit 303; the parameter acquisition unit 301 is used to read the power grid parameters of the multiple first nodes; the first power flow calculation unit 302 is used to perform power flow calculation on the target distribution network G on a time section to obtain the multiple first node voltages, multiple first node active powers and multiple first node reactive powers; wherein the time section n t is the measurement time interval gap within the time to be analyzed T, specifically: According to the plurality of first node voltages, the plurality of first node active powers and the plurality of first node reactive powers, a plurality of first node active voltage sensitivities are obtained by performing quotient calculations. and multiple first node reactive voltage sensitivities The average of multiple first node power and voltage sensitivities is obtained The matrix establishing unit 303 is used to calculate the electrical distance between the first nodes according to the power and voltage sensitivities of the plurality of first nodes. And perform electrical distance normalization to obtain the normalized result And establish the electrical relationship matrix, where the normalized result e ij is the element of the electrical relationship matrix.

[0142] The cluster dynamic division module 203 is used to divide the multiple first nodes into clusters according to the electrical relationship matrix and the preset community discovery algorithm, and compress the divided clusters to obtain multiple second nodes and determine the reactive power of each second node.

[0143] As an example of this embodiment, see Figure 4 , Figure 4 A schematic diagram of a cluster dynamic division module structure of a distribution network voltage control system provided by an embodiment of the present invention. Figure 4 As shown, a cluster dynamic partitioning module provided by the present invention includes: a matrix calculation allocation unit 401 and a node compression unit 402;

[0144] The matrix calculation allocation unit 401 is used to allocate adjacent clusters to the plurality of first nodes according to the elements of the electrical relationship matrix, and calculate the modularity change before and after the allocation.

[0145] The node compression unit 402 is used to determine that the cluster structure no longer changes after determining that the modularity change of the multiple first nodes is less than a preset limit, compress the cluster divided from the multiple first nodes into multiple second nodes, and determine the reactive power of each second node.

[0146] The present invention has fewer computing nodes, higher efficiency and faster calculation. The traditional centralized control method needs to calculate all nodes and distributed photovoltaic parameters of the target distribution network G. A single calculation involves many nodes, a complex system and low efficiency. Through cluster division, the number of nodes is reduced, the system complexity is reduced, and the system control efficiency can be effectively improved.

[0147] The reactive power optimization module 204 is used to optimize the reactive power of the multiple second nodes using a preset sparrow search algorithm, screen out multiple third nodes, and determine the grid parameters of the multiple third nodes within the target distribution network to be analyzed time period.

[0148] As an example of this embodiment, see Figure 5 , Figure 5 A schematic diagram of a reactive power optimization module structure of a distribution network voltage control system provided by an embodiment of the present invention. Figure 5 As shown, a reactive power optimization module provided by the present invention includes: a first sparrow search unit 501 and a reactive power optimization result output unit 502;

[0149] The first sparrow search unit 501 is used to sequentially calculate the reactive power of the second node by the sum of the active power losses of each branch in the cluster. Optimization of reactive power parameters with minimum as the goal;

[0150] The reactive power optimization result output unit 502 is used to select the multiple second nodes that meet the reactive power optimization conditions to form the multiple third nodes, and determine the grid parameters of the multiple third nodes in the target distribution network within the time period to be analyzed.

[0151] The voltage over-limit judgment module 205 is used to determine the voltage of each third node according to the grid parameters of the plurality of third nodes and the preset power flow algorithm; and judge whether the voltage of each third node exceeds the preset voltage limit value according to the voltage of each third node.

[0152] As an example of this embodiment, see Figure 6 , Figure 6 A schematic diagram of a voltage over-limit judgment module structure of a distribution network voltage control system provided by an embodiment of the present invention. Figure 6 As shown, a voltage over-limit judgment module provided by the present invention includes: a second power flow calculation unit 601 and a node voltage judgment unit 602;

[0153] The second power flow calculation unit 601 is used to perform power flow calculation based on the power grid parameters of the plurality of third nodes to obtain the third node voltage;

[0154] The node voltage judgment unit 602 is used to judge whether the preset voltage limit value is exceeded according to the voltage of each third node and the preset voltage limit value, wherein the preset voltage limit value includes: a medium voltage upper limit threshold, a medium voltage lower limit threshold, a low voltage upper limit threshold and a low voltage lower limit threshold; when it is determined that the medium voltage area voltage of each third node is greater than the medium voltage upper limit threshold, or less than the medium voltage lower limit threshold, it is called exceeding the preset voltage limit value. When it is determined that the low voltage area voltage of each third node is greater than the low voltage upper limit threshold, or less than the low voltage lower limit threshold, it is called exceeding the preset voltage limit value.

[0155] The active power optimization module 206 is used to optimize the active power of the multiple third nodes using the preset sparrow search algorithm when it is determined that the voltage of each third node exceeds the preset voltage limit value, screen out multiple fourth nodes, and determine the reactive power and active power of the multiple fourth nodes.

[0156] As an example of this embodiment, see Figure 7 , Figure 7 A schematic diagram of the structure of an active power optimization module of a distribution network voltage control system provided by an embodiment of the present invention. Figure 7 As shown, an active power optimization module provided by the present invention includes: a second sparrow search unit 701 and an active power optimization result output unit 702;

[0157] The second sparrow search unit 701 is used to, when it is determined that the voltage of the third node exceeds the preset voltage limit value, sequentially perform a search on the third node based on the sum of the active power losses of each branch in the cluster. Optimization of active power parameters with minimum as the goal;

[0158] The active power optimization result output unit 702 is used to screen out multiple fourth nodes that meet the active power optimization condition, and determine the reactive power and active power of the multiple fourth nodes.

[0159] The grid control module 207 is used to determine the photovoltaic value of the target distribution network, and control the operating voltage of the target distribution network through the reactive power and active power of the multiple fourth nodes.

[0160] As an example of this embodiment, see Figure 8 , Figure 8 A schematic diagram of the structure of a power distribution network voltage control system power grid control module provided by a certain embodiment of the present invention. Figure 8As shown, a power grid control module provided by the present invention includes: a photovoltaic quantity judgment unit 801 and a voltage control unit 802;

[0161] The photovoltaic quantity judgment unit 801 is used to determine whether the photovoltaic quantity value of the target distribution network exceeds the preset photovoltaic value;

[0162] The voltage control unit 802 is used to control the target distribution network operating voltage value through reactive power regulation of the plurality of fourth nodes in a scenario where the photovoltaic amount is less than the preset photovoltaic value;

[0163] For a scenario where the photovoltaic amount is greater than or equal to the preset photovoltaic value, the target distribution network operating voltage value is jointly adjusted and controlled by the reactive power and active power of the multiple fourth nodes.

[0164] The present invention proposes a dual power regulation idea, which comprehensively considers the impact of reactive power and active power on voltage, and fully copes with two scenarios with less or more distributed photovoltaics. In less scenarios, the distribution network voltage regulation can be achieved only through the reactive power regulation of the inverter. In more scenarios, the distribution network voltage is effectively controlled by a small amount of abandoned light, thereby ensuring the stable operation of the power system.

[0165] A distribution network voltage control system provided by an embodiment of the present invention can reduce the number of nodes that need to be calculated step by step by screening nodes, thereby improving the working efficiency and stability of the power grid. At the same time, by adjusting the power grid voltage in a dual-function manner, the stable operation of the power system can be effectively guaranteed.

[0166] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0167] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0168] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

Claims

1. A distribution network voltage control method, It is characterized in that include: Obtaining grid parameters of a plurality of first nodes in a target distribution network within a time period to be analyzed; Determine the electrical distance between the first nodes according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then establish an electrical relationship matrix according to the electrical distance between the first nodes; Specifically, according to the grid parameters of the multiple first nodes, the target distribution network is subjected to flow calculation on a time section to obtain the multiple first node voltages, multiple first node active powers and multiple first node reactive powers; wherein the time section is a measurement time interval within the time to be analyzed; according to the multiple first node voltages, the multiple first node active powers and the multiple first node reactive powers, multiple first node active voltage sensitivities and multiple first node reactive voltage sensitivities are obtained by taking the quotients, and multiple first node power and voltage sensitivities are obtained by averaging; according to the multiple first node power and voltage sensitivities, the electrical distances between the first nodes are calculated, and the electrical distances are normalized to obtain the normalized results, and the electrical relationship matrix is ​​established, wherein the normalized results are elements of the electrical relationship matrix; According to the electrical relationship matrix and the preset community discovery algorithm, the plurality of first nodes are clustered and the clusters after the division are compressed to obtain a plurality of second nodes and the reactive power of each second node is determined; specifically: according to the elements of the electrical relationship matrix, the plurality of first nodes are assigned adjacent clusters, and the modularity change before and after the assignment is calculated; when it is determined that the modularity change of the plurality of first nodes is less than a preset limit value, it is determined that the cluster structure no longer changes, the clusters after the plurality of first nodes are divided are compressed into a plurality of second nodes, and the reactive power of each second node is determined; The reactive power of the multiple second nodes is optimized by using a preset sparrow search algorithm, multiple third nodes are screened out, and the grid parameters of the multiple third nodes in the target distribution network to be analyzed are determined; specifically: the reactive power of the second nodes is optimized in turn with the sum of active power losses of each branch in the cluster as the minimum, the multiple second nodes that meet the reactive power optimization conditions are screened out to form the multiple third nodes, and the grid parameters of the multiple third nodes in the target distribution network to be analyzed are determined; Determine the voltage of each third node according to the grid parameters of the multiple third nodes and the preset power flow algorithm; specifically: perform power flow calculation with the grid parameters of the multiple third nodes to obtain the voltage of the third node; determine whether the preset voltage limit value is exceeded according to the voltage of each third node and the preset voltage limit value, wherein the preset voltage limit value includes: a medium voltage upper limit threshold, a medium voltage lower limit threshold, a low voltage upper limit threshold and a low voltage lower limit threshold; when it is determined that the medium voltage area voltage of each third node is greater than the medium voltage upper limit threshold, or less than the medium voltage lower limit threshold, it is called exceeding the preset voltage limit value, and when it is determined that the low voltage area voltage of each third node is greater than the low voltage upper limit threshold, or less than the low voltage lower limit threshold, it is called exceeding the preset voltage limit value; Determining whether the voltage of each third node exceeds a preset voltage limit value; When it is determined that the voltage of each third node exceeds the preset voltage limit value, the preset sparrow search algorithm is used to optimize the active power of the multiple third nodes, multiple fourth nodes are screened out, and the reactive power and active power of the multiple fourth nodes are determined; specifically: when it is determined that the voltage of the third node exceeds the preset voltage limit value, the active power parameters of the third nodes are optimized in turn with the minimum sum of the active power losses of each branch in the cluster as the goal, multiple fourth nodes that meet the active power optimization conditions are screened out, and the reactive power and active power of the multiple fourth nodes are determined; The photovoltaic value of the target distribution network is determined, and the operating voltage of the target distribution network is controlled through the reactive power and the active power of the plurality of fourth nodes.

2. A distribution network voltage control method as claimed in claim 1, It is characterized in that The step of determining the photovoltaic value of the target distribution network and controlling the operating voltage of the target distribution network through the reactive power and active power of the plurality of fourth nodes is specifically as follows: For a scenario where the photovoltaic amount is less than a preset photovoltaic value, the target distribution network operating voltage value is controlled by reactive power regulation of the plurality of fourth nodes; For a scenario where the photovoltaic amount is greater than or equal to the preset photovoltaic value, the target distribution network operating voltage value is jointly adjusted and controlled by the reactive power and active power of the multiple fourth nodes.

3. A distribution network voltage control system, It is characterized in that include: Parameter acquisition module, electrical relationship matrix building module, cluster dynamic division module, reactive power optimization module, voltage over-limit judgment module, active power optimization module and power grid control module; The parameter acquisition module is used to obtain the power grid parameters of multiple first nodes in the target distribution network within the time period to be analyzed; The electrical relationship matrix building module is used to determine the electrical distance between each first node according to the grid parameters of the plurality of first nodes and a preset power flow algorithm, and then establish an electrical relationship matrix according to the electrical distance between each first node; It also includes: a parameter acquisition unit, a first power flow calculation unit and a matrix establishment unit; the parameter acquisition unit is used to read the power grid parameters of the multiple first nodes; the first power flow calculation unit is used to perform power flow calculation on the target distribution network on a time section to obtain the multiple first node voltages, multiple first node active powers and multiple first node reactive powers; wherein the time section is a measurement time interval within the time to be analyzed; according to the multiple first node voltages, the multiple first node active powers and the multiple first node reactive powers, multiple first node active voltage sensitivities and multiple first node reactive voltage sensitivities are obtained by taking the quotient, and multiple first node power voltage sensitivities are obtained by averaging; the matrix establishment unit is used to calculate the electrical distance between the first nodes according to the multiple first node power voltage sensitivities, perform electrical distance normalization processing, obtain a normalized result, and establish the electrical relationship matrix, wherein the normalized result is an element of the electrical relationship matrix; The cluster dynamic division module is used to divide the multiple first nodes into clusters according to the electrical relationship matrix and the preset community discovery algorithm, and compress the divided clusters to obtain multiple second nodes and determine the reactive power of each second node; it also includes: a matrix calculation allocation unit and a node compression unit; the matrix calculation allocation unit is used to allocate adjacent clusters to the multiple first nodes according to the elements of the electrical relationship matrix, and calculate the modularity change before and after the allocation; the node compression unit is used to determine that the cluster structure no longer changes after determining that the modularity change of the multiple first nodes is less than a preset limit value, compress the clusters after the multiple first nodes are divided into multiple second nodes, and determine the reactive power of each second node; The reactive power optimization module is used to optimize the reactive power of the multiple second nodes using a preset sparrow search algorithm, screen out multiple third nodes, and determine the grid parameters of the multiple third nodes in the target distribution network to be analyzed time period; it also includes: a first sparrow search unit and a reactive power optimization result output unit; the first sparrow search unit is used to sequentially optimize the reactive power parameters of the reactive power of the second nodes with the goal of minimizing the sum of the active power losses of each branch in the cluster; the reactive power optimization result output unit is used to screen out the multiple second nodes that meet the reactive power optimization conditions to form the multiple third nodes, and determine the grid parameters of the multiple third nodes in the target distribution network to be analyzed time period; The voltage over-limit judgment module is used to determine the voltage of each third node according to the grid parameters of the multiple third nodes and the preset power flow algorithm; and judge whether it exceeds the preset voltage limit value according to the voltage of each third node; and also includes: a second power flow calculation unit and a node voltage judgment unit; the second power flow calculation unit is used to perform power flow calculation with the grid parameters of the multiple third nodes to obtain the third node voltage; the node voltage judgment unit is used to judge whether it exceeds the preset voltage limit value according to the voltage of each third node and the preset voltage limit value, wherein the preset voltage limit value includes: a medium voltage upper limit threshold, a medium voltage lower limit threshold, a low voltage upper limit threshold and a low voltage lower limit threshold; when it is determined that the medium voltage area voltage of each third node is greater than the medium voltage upper limit threshold, or less than the medium voltage lower limit threshold, it is called exceeding the preset voltage limit value, and when it is determined that the low voltage area voltage of each third node is greater than the low voltage upper limit threshold, or less than the low voltage lower limit threshold, it is called exceeding the preset voltage limit value; The active power optimization module is used to, when it is determined that the voltage of each third node exceeds the preset voltage limit value, use the preset sparrow search algorithm to perform active power optimization on the active power of the multiple third nodes, screen out multiple fourth nodes, and determine the reactive power and active power of the multiple fourth nodes; it also includes: a second sparrow search unit and an active power optimization result output unit; the second sparrow search unit is used to, when it is determined that the voltage of the third node exceeds the preset voltage limit value, sequentially perform active power parameter optimization on the third nodes with the goal of minimizing the sum of the active power losses of each branch in the cluster; the active power optimization result output unit is used to screen out multiple fourth nodes that meet the active power optimization conditions, and determine the reactive power and active power of the multiple fourth nodes; The power grid control module is used to determine the photovoltaic value of the target power distribution network, and control the operating voltage of the target power distribution network through the reactive power and active power of the multiple fourth nodes.

4. A distribution network voltage control system as claimed in claim 3, It is characterized in that The power grid control module is used to determine the photovoltaic value of the target distribution network and control the operating voltage of the target distribution network according to the reactive power optimization result and the active power optimization result, and also includes: Photovoltaic quantity judgment unit and voltage control unit; The photovoltaic quantity judgment unit is used to determine whether the photovoltaic quantity value of the target distribution network exceeds the preset photovoltaic value; The voltage control unit is used to control the target distribution network operating voltage value through reactive power regulation of the plurality of fourth nodes in a scenario where the photovoltaic amount is less than the preset photovoltaic value; For a scenario where the photovoltaic amount is greater than or equal to the preset photovoltaic value, the target distribution network operating voltage value is jointly adjusted and controlled by the reactive power and active power of the multiple fourth nodes.

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