A power distribution network voltage regulation resource configuration-operation collaborative control system, device and method

Abstract

The application relates to the technical field of power distribution network operation control, in particular to a power distribution network voltage regulation resource configuration-operation collaborative control system, equipment and method. The method collects voltage data of load nodes of a power distribution network, calculates voltage deviation rates to screen out out-of-limit nodes; subsequently, taking a transformer as a root node, a directed acyclic graph is generated based on cable wiring, an out-of-limit path is traversed, a coupling relationship is judged according to voltage deviation rates of adjacent SVRs corresponding to load nodes in the path, and an SVR marked value is determined in combination with a symbolic difference method; finally, in combination with the marked value, a double-target function and a constraint condition are constructed with the minimum voltage deviation of the power distribution network and the minimum action cost of the voltage regulation resource configuration as targets, an optimization algorithm is used to solve the optimal gear of each SVR, and the optimal configuration and operation collaborative control of the voltage regulation resource of the power distribution network are realized.

Description

Technical Field

[0001] This application relates to the field of power distribution network operation control technology, specifically to a power distribution network voltage regulation resource allocation-operation coordinated control system, equipment and method. Background Technology

[0002] With the high proportion of distributed photovoltaic power being connected to the distribution network, the power flow characteristics of the grid are becoming increasingly complex, which can easily lead to problems such as voltage exceeding limits and increased voltage fluctuations. The series line voltage regulator (SVR) in the distribution network is a key device for voltage regulation. In order to ensure the coordinated and stable operation of the distribution network, it is necessary to optimize the SVR taps and the number of capacitor switching groups to achieve a reasonable allocation of voltage regulation resources in the distribution network.

[0003] Existing research on resource allocation for SVR devices often relies on simplified voltage drop analysis, failing to fully consider the dynamic characteristics of their tap adjustment and the global optimization of maintenance costs. It also ignores the coupling relationship between resource allocation and operational coordination, making it difficult to make accurate decisions on optimal equipment allocation. This can easily lead to blind SVR tap adjustments in faulty areas such as those with voltage exceeding limits. Furthermore, by ignoring the voltage interaction between distribution network topology lines, unnecessary distribution network voltage regulation actions can result in wasted costs. Summary of the Invention

[0004] In view of the above, it is necessary to provide a power distribution network voltage regulation resource allocation-operation coordinated control system, equipment and method to solve the above problems.

[0005] According to one aspect of this application, a method for coordinated control of voltage regulation resource allocation and operation in a distribution network is provided, the method comprising:

[0006] Collect voltage data from each load node in the distribution network;

[0007] Calculate the voltage deviation rate of each load node in the distribution network using voltage data, and screen out overload nodes;

[0008] A directed acyclic graph is generated based on the cable connection of the distribution network with the transformer as the root node. All over-limit paths formed by the over-limit load nodes are traversed. The coupling relationship between adjacent SVRs is determined according to the voltage deviation rate of the load nodes corresponding to adjacent SVRs in the over-limit path. The label value of each SVR is determined by combining the sign difference method.

[0009] By combining the SVR marker value, a dual objective function is constructed to minimize the cost of voltage regulation resource allocation and the voltage deviation of the distribution network. Constraints are established, and optimization algorithms are used to solve for the optimal SVR level of each distribution network, thereby enabling coordinated control of voltage regulation resource allocation and operation in the distribution network.

[0010] Preferably, the voltage deviation rate is specifically the percentage of the difference between the actual voltage and the standard voltage relative to the standard voltage;

[0011] The specific steps for screening overload nodes are as follows: obtain the absolute value of the voltage deviation rate of each load node; if the absolute value is greater than the preset allowable voltage fluctuation threshold, determine that the corresponding load node is an overload node.

[0012] Preferably, the generation of the directed acyclic graph specifically involves:

[0013] Each load node in the distribution network is used as a node of the graph, and the transmission lines between the load nodes are used as edges of the graph. The power supply side of the transformer is used as the root node, and the physical wiring direction radiating from the root node to each load node is used as the fixed direction of the edge, thus generating a directed acyclic graph of the distribution network.

[0014] Preferably, the over-limit path is specifically:

[0015] In the directed acyclic graph, the node that satisfies the voltage limit and has no predecessor node and whose predecessor node is operating normally is taken as the starting point of traversal; the node that satisfies the voltage limit and has no successor node and whose successor node is operating normally is taken as the ending point of traversal.

[0016] A depth-first traversal algorithm is used to extract a sequence of consecutive overload nodes connecting the starting point and the ending point of the traversal in the directed acyclic graph, which is then used as the overload path.

[0017] Preferably, determining the tag value for each SVR specifically involves:

[0018] For each out-of-limit path, count the number of SVRs it passes through;

[0019] If no SVR is encountered, obtain the nearest upstream SVR on the path and mark it as 1; if there is no upstream SVR, obtain the nearest downstream SVR and mark it as 1.

[0020] If only one SVR is passed through, then mark that SVR as 1;

[0021] If two or more SVRs are encountered, then two adjacent SVRs are selected sequentially along the topology direction to be divided into upstream SVR and downstream SVR, and the following operations are performed: obtain all overload nodes within the topology segment where these two adjacent SVRs are located; take the load node with the largest voltage deviation rate as the starting point and arrange them sequentially along the topology path towards the low-voltage side to form a voltage overload sequence; calculate the difference between the next element and the previous element in the voltage overload sequence to generate a first-order difference sequence; if all elements in the first-order difference sequence are negative, then keep the existing label value of the upstream SVR unchanged and mark the downstream SVR as 0; if there is an element greater than or equal to 0 in the first-order difference sequence, then keep the existing label value of the upstream SVR unchanged and mark the downstream SVR as 1;

[0022] After traversing all out-of-limit paths in the distribution network, if the same SVR has different flag values ​​in different out-of-limit paths, then 1 is taken as the final flag value of the SVR.

[0023] Preferably, the dual objective function specifically includes a first objective function that minimizes the cost of voltage regulation resource allocation and a second objective function that minimizes the voltage deviation of the distribution network, wherein the formula for the first objective function is: The formula for the second objective function is: ; This indicates minimizing the cost of configuring voltage regulation resources. This indicates the total number of SVRs installed in the distribution network. This represents the cost of the shifting action of the m-th SVR in the distribution network. It is obtained by multiplying the absolute difference between the shifted and unshifted shifts by the cost per unit of shifts. This represents the tag value of the m-th SVR in the distribution network. This represents minimizing the voltage deviation in the distribution network. This represents the total number of load nodes in the distribution network. This represents the voltage deviation rate of the i-th load node.

[0024] Preferably, the construction constraints specifically include:

[0025] Node voltage and branch current constraints: The voltage of each load node is limited to a preset safe range and the current passing through the line section between each load node is not greater than the maximum allowable current value of that line section.

[0026] Power flow calculation constraints: Based on the Newton-Raphson method, the active and reactive power balance equations of each node in the distribution network are established. For load nodes that are not connected to distributed photovoltaic and / or capacitor banks, the corresponding photovoltaic and capacitor injected power terms are all taken as 0.

[0027] SVR operating constraints include limiting the SVR's gear ratio to a fixed discrete mapping relationship, and limiting the calculated apparent power flowing through the line segment where the SVR is located to be less than or equal to the SVR's rated apparent power.

[0028] Preferably, the step of using optimization algorithms to solve for the optimal tap position of each SVR in the distribution network and performing coordinated control of the distribution network voltage regulation resource allocation and operation specifically includes:

[0029] Remove SVRs with a label value of 0, and include all SVRs with a label value of 1 in the search dimension of the particle swarm optimization algorithm to initialize the particle swarm.

[0030] Based on the aforementioned dual objective function, a fitness function is constructed that minimizes the fitness function, which is a weighted sum of the action cost normalized to the maximum value and the voltage deviation normalized to the maximum value.

[0031] In each particle swarm iteration update, the nearest integer function is used to discretize the continuous floating-point elements in the particle vector, convert them into integer levels, and then perform power flow calculation and fitness function evaluation in combination with the constraints.

[0032] After the iteration is completed, the optimal solution of the particle swarm is obtained as the best gear for each SVR in the distribution network, and control commands are issued to drive the corresponding SVR in the distribution network to adjust the gear.

[0033] According to another aspect of this application, a distribution network voltage regulation resource configuration-operation coordinated control device is provided, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of any of the methods described above.

[0034] According to another aspect of this application, a distribution network voltage regulation resource allocation-operation coordinated control system is provided, wherein the system stores a computer program, which, when executed by a processor, implements any of the methods described above.

[0035] This application has at least the following beneficial effects:

[0036] Existing methods for coordinating the allocation and operation of voltage regulation resources in distribution networks often neglect the objective voltage interaction effects between distribution network topologies. This leads to some SVRs (Support Voltage Regulators) performing voltage regulation actions unnecessarily, resulting in wasted voltage regulation costs. This application combines load nodes with voltage limits in the distribution network with a directed acyclic graph (DAG). By traversing all limit-exceeding paths, it deeply analyzes the coupling relationship between the voltage deviation rates of each SVR and its associated load nodes along the limit-exceeding paths. Based on this, a signed difference method is introduced to mark the actions of each SVR, accurately establishing a coupling relationship model between adjacent SVRs and related voltage-limit-exceeding load nodes. This accurately identifies SVRs that need to perform voltage regulation actions and those that do not, thus avoiding ineffective voltage regulation operations caused by ignoring voltage interaction effects.

[0037] Based on the SVR (Signal Voltage Regulator) label value, a dual objective function was constructed, focusing on minimizing the cost of voltage regulation resource configuration and minimizing distribution network voltage deviation, with corresponding constraints set. An optimization algorithm was used to solve for the optimal tap position of all SVRs in the distribution network, achieving precise configuration and coordinated operation control of voltage regulation resources. This method effectively avoids repetitive or redundant voltage regulation actions by SVRs with strong coupling relationships. While ensuring effective improvement of distribution network voltage exceedance issues and maintaining distribution network voltage stability, it minimizes the cost of voltage regulation actions, achieving dual optimization of voltage regulation effect and economy, and providing reliable technical support for the efficient and stable operation of the distribution network. Attached Figure Description

[0038] Figure 1 A flowchart illustrating the steps of a distribution network voltage regulation resource allocation and operation coordinated control method provided in this application;

[0039] Figure 2 The equivalent circuit diagram of voltage regulation in the power distribution network provided in this application. Detailed Implementation

[0040] Please see Figure 1 The diagram illustrates a flowchart of a distribution network voltage regulation resource allocation-operation coordinated control method according to an embodiment of this application. The method includes the following steps:

[0041] Processing step 1: Collect voltage data of each load node in the distribution network.

[0042] In this application, the equivalent circuit diagram of voltage regulation in the distribution network is as follows: Figure 2 As shown, 101 represents a transformer, 102 represents a 10kV busbar, 103, 104, and 105 all represent series line voltage regulators (SVRs), 106 represents distributed photovoltaics, P1-P11 all represent load nodes, and PV represents photovoltaic power generation.

[0043] The distribution network uses Data Terminal Units (DTUs) to collect voltage data from each load node in real time, and transmits the collected voltage data to the distribution network voltage regulation resource allocation-operation coordinated control system using wireless communication technology. Furthermore, the DTUs synchronously collect active and reactive power data for nodes corresponding to distributed photovoltaic (PV) injection, as well as the active and reactive power consumed by the nodes containing related loads and capacitor banks. All the collected operating status data is filtered, denoised, and clock-aligned internally by the DTU, and the voltage data is the effective voltage value calculated based on the power frequency period. DTU data acquisition, denoising, and clock alignment are well-known technologies, and their specific implementations will not be elaborated upon. In this embodiment, the DTU's sampling frequency is 1 kHz, and the power frequency period is 0.02 s.

[0044] Processing step 2: Calculate the voltage deviation rate of each load node in the distribution network using voltage data, and screen out overload nodes.

[0045] The nonlinear loads brought about by the random power output of distributed photovoltaic power grids usually cause voltage fluctuations at various load nodes in the distribution network. If the voltage of the load node exceeds the standard voltage range of the distribution network, it is necessary to use the SVR in the distribution network line to regulate the voltage, restore the stability of the distribution network voltage supply, and ensure the quality of the power supply voltage.

[0046] For the i-th load node in the distribution network, calculate the voltage deviation rate of the i-th load node. The specific formula is as follows: This reflects the degree to which the load node voltage deviates from the standard voltage of the distribution network. Among them, This represents the voltage data of the i-th load node at the current moment; This indicates the standard voltage of the distribution network; in this example, it is 10kV. The positive or negative sign indicates the polarity of the load node voltage deviation, rather than the deviation magnitude. A positive sign indicates that the load node voltage is greater than the standard voltage, and a negative sign indicates that the load node voltage is less than the standard voltage.

[0047] The smaller the value, the more consistent the load node voltage is with the standard voltage of the distribution network, meaning that the voltage of each load node in the distribution network is in a stable operating state; conversely, the larger the value, the more consistent the voltage is with the standard voltage of the distribution network. The larger the value, the more the load node voltage deviates from the standard voltage of the distribution network, meaning that the load node voltage fluctuates violently and is prone to voltage over-limit situations, requiring the use of SVR for voltage regulation.

[0048] According to the operating regulations for power transformers, the permissible voltage fluctuation threshold for the distribution network is... To assess whether there is a risk of voltage over-limit at the i-th load node, a comparison is made. and Size, if Less than or equal to This indicates that the load node is operating normally and no voltage over-limit has occurred; conversely, if... Greater than This indicates that the voltage at the load node is above the limit, and the load node is an over-limit load node.

[0049] Processing step 3: Generate a directed acyclic graph based on the cable connection of the distribution network with the transformer as the root node, traverse all over-limit paths formed by the over-limit load nodes, determine the coupling relationship of adjacent SVRs based on the voltage deviation rate of the load nodes corresponding to adjacent SVRs in the over-limit path, and determine the label value of each SVR by combining the sign difference method.

[0050] In a distribution network topology, there is a significant voltage coupling effect between load nodes. When an upstream load node experiences a voltage overrun, this overrun can propagate down the network, easily causing a cascading voltage overrun at adjacent downstream load nodes.

[0051] In a multi-level series-connected voltage regulator (SVR) scenario in a distribution network, since the voltage regulation function of the SVR mainly affects the downstream, when two adjacent SVRs in series experience voltage over-limit events at nearby load nodes simultaneously, a differentiated strategy needs to be adopted based on the coupling strength between the load nodes: if the coupling is strong, the downstream over-limit event is mostly caused by upstream conduction, and in this case, only the upstream SVR needs to be adjusted to balance the voltage recovery of both upstream and downstream, thereby avoiding the waste of resources caused by ineffective downstream voltage regulation; if the coupling is weak, it indicates that the over-limit events are independent of each other, and a dual SVR collaborative control mechanism needs to be activated to achieve global voltage management by reasonably allocating voltage regulation resources.

[0052] To analyze the voltage over-limit coupling relationship between two adjacent load nodes near SVRs, a topology tree is constructed radiating outwards from the substation or transformer power supply side as the root node of the topology, serving as a fixed direction for the directed acyclic graph.

[0053] Next, the voltage deviation rate of each node in the directed acyclic graph is analyzed to identify nodes with voltage exceeding the limit. A depth-first search algorithm is then used to traverse these nodes. The methods for determining the starting and ending points of the traversal are as follows:

[0054] If a node has a voltage limit exceeding the limit and there is no predecessor node or all predecessor nodes are operating normally, then that node is taken as the starting point of the traversal. If a node has a voltage limit exceeding the limit and there is no successor node or all successor nodes are operating normally, then that node is taken as the ending point of the traversal. When there is only one node in the traversal path, that node is both the starting point and the ending point of the traversal.

[0055] After traversing the directed acyclic graph, obtain several out-of-bounds paths.

[0056] For one of the over-limit paths, count the series line voltage regulators (SVRs) in the distribution network that are adjacent to the starting point, ending point, or any two intermediate nodes of that path.

[0057] If the over-limit path does not pass through any SVR, the nearest upstream SVR of the path will complete the distribution network voltage regulation. If there is no upstream SVR, the nearest downstream SVR will cooperate to complete the distribution network voltage regulation. After determining the SVR subject to cooperative takeover, the SVR is marked as 1, indicating that the SVR needs to allocate voltage regulation resources and perform voltage regulation actions.

[0058] If the over-limit path passes through only one SVR, mark that SVR as 1, and the subsequent voltage regulation of the distribution network will be mainly completed by that SVR.

[0059] If the over-limit path passes through two or more SVRs, the relationship between the over-limit load nodes' voltage over-limits within the topology segment containing the two adjacent SVRs needs to be analyzed sequentially. The topology segment refers to all over-limit load nodes within this topology segment, bounded by the preceding SVR (or the starting point of the path if there is no preceding SVR) of the upstream SVR and the following SVR (or the ending point of the path if there is no following SVR) of the downstream SVR on the over-limit path.

[0060] Unlike traditional distribution networks where unidirectional power flow leads to a gradual decrease in voltage during undervoltage scenarios, in high-proportion distributed photovoltaic (PV) grid-connected systems, when power backflow occurs, the voltage at the PV grid-connected node becomes the peak voltage of its respective line segment, gradually decreasing upstream and downstream. The voltage deviation rate of the over-limit load nodes within the topology segment containing two adjacent SVRs in this over-limit path is obtained. Starting from the load node with the largest voltage deviation rate in this over-limit path, these nodes are arranged sequentially along the topology path towards the low-voltage side, forming a voltage over-limit sequence.

[0061] It should be noted that the installation distance between two adjacent SVRs in the distribution network is generally 3-5km. Therefore, the number of overload nodes in the topology section where the two adjacent SVRs are located within the transformer power supply range is relatively abundant. In addition, the number of load nodes affected by the reverse power flow generated by the high proportion of distributed photovoltaic grid connection is also relatively large.

[0062] Due to the random output of distributed photovoltaic power and bidirectional power flow, the voltage deviation rate of each load node fluctuates. To accurately identify the progressively decreasing characteristics caused by the same source, the sign difference method is used for discrimination.

[0063] Specifically, the number of elements in the voltage exceedance sequence is then determined. If the voltage exceedance sequence contains only a single element, the high-voltage side SVR in that topology segment is marked as 1, and the low-voltage side SVR is marked as 0. If the voltage exceedance sequence contains two or more elements, the difference between the subsequent element and the preceding element in the voltage exceedance sequence is calculated to generate a first-order difference sequence. Then, the sign of the first-order difference sequence is evaluated. If all elements in the first-order difference sequence are negative, it indicates that the voltage deviation sequence in the voltage exceedance sequence exhibits a progressively decreasing characteristic. The voltage exceedance of the downstream load nodes related to the two adjacent SVRs in this exceedance path is mainly caused by the coupling effect of the voltage exceedance of the upstream load nodes in this path. Therefore... Only voltage regulation resource allocation is needed for the upstream SVR; no voltage regulation resource allocation is required for the downstream SVR. In this case, the upstream SVR is marked as 1, and the downstream SVR is marked as 0. Conversely, if there are still positive numbers or 0 elements in the first-order difference sequence, it indicates that the voltage over-limit of the overload nodes in the topological segment where the two adjacent SVRs are located is still affected by the random output of photovoltaic power, resulting in random fluctuations in voltage over-limit and the voltage deviation rate losing its stepwise decreasing characteristic. This indicates that the coupling relationship between the voltage over-limit of the upstream and downstream load nodes is relatively weak, and both adjacent SVRs need to be configured with voltage regulation resources and take voltage regulation actions. In this case, both adjacent SVRs are marked as 1.

[0064] With a step size of 1, the voltage deviation rate of the overload nodes in the topology segment where two adjacent SVRs are located in the over-limit path is analyzed. The sign difference method is used to determine whether these two SVRs need voltage regulation resource allocation. In particular, since the upstream SVR in these two adjacent SVRs belongs to the downstream SVR in the two adjacent SVRs analyzed in the previous analysis, it has been marked and will not be re-marked in this analysis.

[0065] For example, if the upstream SVR in this analysis was marked as 0 in the previous analysis, even if the sign difference method determines that both SVRs need voltage regulation resource configuration, only the downstream SVR will still be configured with voltage regulation resources. This is because the voltage near the upstream SVR will recover automatically after the voltage regulation resource configuration and operation of the previous SVR, so no voltage regulation configuration is required, and only the downstream SVR needs to be marked as 1. If the upstream SVR in this analysis was marked as 1 in the previous analysis, regardless of whether the sign difference method determines that both SVRs need voltage regulation resource configuration, only the downstream SVR will be marked as 0 or 1.

[0066] Similarly, all SVRs along the over-limit path are marked. Then other over-limit paths are analyzed. Since different over-limit paths may pass through the same SVR, if the same SVR has already been marked as 1 in other paths, the SVR will not be remarked. Conversely, if the SVR has already been marked as 0 in other paths, but needs to be marked as 1 in the current path, it needs to be remarked as 1. Otherwise, it will be difficult for the voltage over-limit load node in the over-limit path to return to normal operation.

[0067] Processing step 4: Combining the SVR marker value, construct a dual objective function that minimizes the cost of voltage regulation resource configuration and the voltage deviation of the distribution network. Construct constraints, use optimization algorithms to solve for the optimal SVR level of each distribution network, and perform coordinated control of voltage regulation resource configuration and operation of the distribution network.

[0068] To address the issue of voltage exceeding limits in distribution networks caused by high-proportion distributed photovoltaic (PV) grid integration, SVR (Signal Voltage Regulator) adjustment is typically coordinated with capacitor switching. This application fully considers the voltage interaction between distribution network topologies to avoid blindly performing unnecessary SVR adjustments, which would waste costs associated with unnecessary distribution network voltage regulation. Therefore, a dual objective function is constructed to minimize the cost of voltage regulation resource allocation and the distribution network voltage deviation. ; ;

[0069] First objective function This indicates minimizing the cost of configuring voltage regulation resources. This indicates the total number of SVRs installed in the distribution network. This represents the cost of the adjustment action of the m-th SVR in the distribution network. Its value is equal to the product of the absolute difference between the SVR's adjusted position and its original position, and the cost per unit number of positions. The original position of the SVR is the actual physical operating position of each SVR, which is collected and uploaded in real time by the DTU through the communication network before executing this optimization calculation instruction. The cost per unit number of positions is equal to the ratio of the total cost of a single SVR to the total number of positions. This represents the flag value of the m-th SVR in the distribution network, and its value can be 0 or 1.

[0070] Second objective function This represents minimizing the voltage deviation in the distribution network. This represents the total number of load nodes in the distribution network.

[0071] The node voltage and branch current constraints are expressed as follows: ; ; In the formula, This represents the voltage of the i-th load node at the current moment. and These represent the lower and upper limits of the voltage exceeding the limit for the i-th load node, respectively, and are 10kV × (1 and 10kV×(1 ; This represents the current flowing through the line segment between the i-th and j-th load nodes. This indicates the maximum current allowed to pass through this section of the line.

[0072] The constraints for power flow calculation using the Newton-Raphson method can be expressed as: ; ; ; ; In the formula, , These represent the net active power and reactive power injected into the i-th load node at the current moment, respectively. These represent the voltages of the i-th and j-th load nodes, respectively. This represents the voltage phase angle difference between load node i and load node j. Let represent the real conductance and imaginary susceptance of the corresponding elements of load node i and load node j in the nodal admittance matrix, respectively. This represents the active power injected into the i-th load node by distributed photovoltaic power. Let represent the reactive power injected into the i-th load node by distributed photovoltaic power and capacitor banks, respectively. These represent the active and reactive power consumed by the i-th load node, respectively. The Newton-Raphson power flow calculation is a well-known technique, and its specific implementation will not be elaborated upon. For load nodes not connected to distributed photovoltaic and / or capacitor banks, their corresponding... , , The value is directly set to 0.

[0073] SVR gear constraints:

[0074] The SVR setting is adjusted via an on-load tap changer, and the settings are discrete integers. In this embodiment, there are 21 SVR settings, with the middle setting (n<11) corresponding to a strain ratio k=1. >1, SVR is in boost mode; when n>11 <1, SVR is in step-down mode, and the gear ratio changes in increments of 0.006 for each gear adjustment. Therefore, the gear ratio corresponding to gear n is: SVR adjustment is considered as a change in the turns ratio of a series ideal transformer. Based on the stated turns ratio... This equivalently corrects the mutual admittance and self admittance parameters of the SVR associated branch in the nodal admittance matrix (i.e., substituting the corrected conductance and susceptance components into the real part of the admittance matrix elements). With the imaginary part (Item). Subsequently, the Newton-Raphson power flow calculation iteration is performed using the updated node admittance matrix parameters to solve for the voltage at each load node that satisfies the power balance constraint. The Newton-Raphson method for power flow calculation iteratively solves for the voltage at each load node that satisfies the constraint conditions based on the correspondence between the transformer ratio and the load node voltage.

[0075] SVR capacity constraints: ; In the formula, This indicates the rated apparent power of the SVR. Let these represent the active power and reactive power flowing through the line segment where the SVR is located (with load nodes i and j at both ends of the line segment). The value is used to calculate the cost of upper-layer voltage regulation resource configuration actions after each power flow calculation update. The power flow calculation method is a well-known technology, and the specific implementation will not be described in detail.

[0076] To address the issue of voltage exceeding limits in the distribution network, and considering the aforementioned dual objective function and constraints, a particle swarm optimization algorithm is employed to determine the optimal operating level for each SVR. The fitness function is: ,in, The weights are preset, and their sum equals 1. The two objective functions... Since the contribution to finding the optimal solution for the particle swarm optimization is basically the same, it is preset to 0.5 in this embodiment. This represents the cost of voltage regulation resource allocation actions after maximum value normalization. The denominator of the maximum value normalization is equal to the total cost of all markers in the distribution network. The sum of the maximum shifting costs that the SVR can generate when shifting from the current operating gear to the extreme gear (i.e., the lowest gear 1 or the highest gear 21, which is furthest from the current gear), This represents the voltage deviation of the distribution network after normalization of the maximum value. The denominator of the normalization of the maximum value is determined based on the historical transformer power supply experience of the distribution network. Specifically, the voltage deviation rate when the load node experiences voltage over-limit is generally between 5% and 10%. Therefore, the denominator of the normalization of the maximum value is determined to be 10% based on the historical operating experience of the distribution network. That is, assuming that the voltage deviation rate of all N load nodes reaches the maximum historical over-limit boundary of 10%, the theoretical maximum value that the average voltage deviation of the distribution network can reach.

[0077] Among them, the mark The SVR does not participate in the spatial search iteration of the particle swarm optimization, thus avoiding the particle swarm optimization direction from approaching the direction that ignores the cost of voltage regulation resource allocation actions. The SVR (Short-Range Dynamics) of the particle vector interferes with the accuracy of the optimal solution. The length of each particle vector is equal to the length of the marker in the distribution network. The number of SVRs is determined, and each element in the particle vector represents the optimal tap position for each SVR in the distribution network. Since the SVR tap position is a discrete variable, in each particle swarm iteration update, the continuous floating-point elements in the particle vector are discretized using the nearest integer function, and then converted into integer tap positions. The power flow calculation is then performed to obtain the electrical estimated state of each node in the network. The estimated state of each node is then substituted into the constraints for verification. For particles that satisfy all constraints, a normal fitness evaluation is output. If a specific tap position combination causes the power flow state to violate any of the node voltage constraints, branch current constraints, or SVR apparent power constraints, a large penalty constant is added to its calculated score in the fitness scoring stage, or the particle's state is directly marked as failed and discarded. After iteration, the optimal solution of the swarm that was not eliminated is obtained. In this application, the initial population size is 100, both learning factors are initially set to 1, and the inertia weight is decayed from 0.8 to 0.4 using a linear decay strategy. The number of iterations is 100. After the iterations are completed, the optimal solution of the particle swarm optimization is obtained, which achieves the optimization objectives of minimizing the cost of voltage regulation resource allocation in the distribution network and minimizing the voltage deviation in the distribution network. The optimal solution of the particle swarm optimization includes the optimal tap position of each SVR in the distribution network. By controlling the tap position of each SVR in the distribution network to be consistent with the optimal solution, the voltage over-limit problem in the distribution network is effectively improved with the minimum voltage regulation cost.

[0078] Based on the same concept as the method embodiments of this application, a distribution network voltage regulation resource configuration-operation coordinated control device is provided, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any of the methods described above.

[0079] Based on the same concept as the method embodiments of this application, a distribution network voltage regulation resource allocation-operation coordinated control system is provided. The system stores a computer program, which, when executed by a processor, implements any of the methods described above.

Claims

1. A method for coordinated control of voltage regulation resource allocation and operation in a power distribution network, characterized in that, The method includes the following steps: Collect voltage data from each load node in the distribution network; Calculate the voltage deviation rate of each load node in the distribution network using voltage data, and screen out overload nodes; A directed acyclic graph is generated based on the cable connection of the distribution network with the transformer as the root node. All over-limit paths formed by the over-limit load nodes are traversed. The coupling relationship between adjacent SVRs is determined according to the voltage deviation rate of the load nodes corresponding to adjacent SVRs in the over-limit path. The label value of each SVR is determined by combining the sign difference method. By combining the SVR marker value, a dual objective function is constructed to minimize the cost of voltage regulation resource allocation and the voltage deviation of the distribution network. Constraints are established, and optimization algorithms are used to solve for the optimal SVR level of each distribution network, thereby enabling coordinated control of voltage regulation resource allocation and operation in the distribution network.

2. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The voltage deviation rate is specifically the percentage of the difference between the actual voltage and the standard voltage relative to the standard voltage. The specific steps for screening overload nodes are as follows: obtain the absolute value of the voltage deviation rate of each load node; if the absolute value is greater than the preset allowable voltage fluctuation threshold, determine that the corresponding load node is an overload node.

3. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The generation of the directed acyclic graph specifically involves: Each load node in the distribution network is used as a node of the graph, and the transmission lines between the load nodes are used as edges of the graph. The power supply side of the transformer is used as the root node, and the physical wiring direction radiating from the root node to each load node is used as the fixed direction of the edge, thus generating a directed acyclic graph of the distribution network.

4. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The specific out-of-limit path is: In the directed acyclic graph, the node that satisfies the voltage limit and has no predecessor node and whose predecessor node is operating normally is taken as the starting point of traversal; the node that satisfies the voltage limit and has no successor node and whose successor node is operating normally is taken as the ending point of traversal. A depth-first traversal algorithm is used to extract a sequence of consecutive overload nodes connecting the starting point and the ending point of the traversal in the directed acyclic graph, which is then used as the overload path.

5. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The determination of the tag value for each SVR is specifically as follows: For each out-of-limit path, count the number of SVRs it passes through; If no SVR is encountered, obtain the nearest upstream SVR on the path and mark it as 1; if there is no upstream SVR, obtain the nearest downstream SVR and mark it as 1. If only one SVR is passed through, then mark that SVR as 1; If two or more SVRs are encountered, then two adjacent SVRs are selected sequentially along the topology direction to be divided into upstream SVR and downstream SVR, and the following operations are performed: obtain all overload nodes within the topology segment where these two adjacent SVRs are located; take the load node with the largest voltage deviation rate as the starting point and arrange them sequentially along the topology path towards the low-voltage side to form a voltage overload sequence; calculate the difference between the next element and the previous element in the voltage overload sequence to generate a first-order difference sequence; if all elements in the first-order difference sequence are negative, then keep the existing label value of the upstream SVR unchanged and mark the downstream SVR as 0; if there is an element greater than or equal to 0 in the first-order difference sequence, then keep the existing label value of the upstream SVR unchanged and mark the downstream SVR as 1; After traversing all out-of-limit paths in the distribution network, if the same SVR has different flag values ​​in different out-of-limit paths, then 1 is taken as the final flag value of the SVR.

6. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The dual objective function specifically includes a first objective function that minimizes the cost of voltage regulation resource allocation and a second objective function that minimizes the voltage deviation in the distribution network. The formula for the first objective function is: The formula for the second objective function is: ; This indicates minimizing the cost of configuring voltage regulation resources. This indicates the total number of SVRs installed in the distribution network. This represents the cost of the shifting action of the m-th SVR in the distribution network. It is obtained by multiplying the absolute difference between the shifted and unshifted shifts by the cost per unit of shifts. This represents the tag value of the m-th SVR in the distribution network. This represents minimizing the voltage deviation in the distribution network. This represents the total number of load nodes in the distribution network. This represents the voltage deviation rate of the i-th load node.

7. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The construction constraints specifically include: Node voltage and branch current constraints: The voltage of each load node is limited to a preset safe range and the current passing through the line section between each load node is not greater than the maximum allowable current value of that line section. Power flow calculation constraints: Based on the Newton-Raphson method, the active and reactive power balance equations of each node in the distribution network are established. For load nodes that are not connected to distributed photovoltaic and / or capacitor banks, the corresponding photovoltaic and capacitor injected power terms are all taken as 0. SVR operating constraints include limiting the SVR's gear ratio to a fixed discrete mapping relationship, and limiting the calculated apparent power flowing through the line segment where the SVR is located to be less than or equal to the SVR's rated apparent power.

8. The distribution network voltage regulation resource allocation-operation coordinated control method as described in claim 1, characterized in that, The method of using optimization algorithms to solve for the optimal tap position of each SVR in the distribution network and to perform coordinated control of the distribution network voltage regulation resource allocation and operation is as follows: Remove SVRs with a label value of 0, and include all SVRs with a label value of 1 in the search dimension of the particle swarm optimization algorithm to initialize the particle swarm. Based on the aforementioned dual objective function, a fitness function is constructed that minimizes the fitness function, which is a weighted sum of the action cost normalized to the maximum value and the voltage deviation normalized to the maximum value. In each particle swarm iteration update, the nearest integer function is used to discretize the continuous floating-point elements in the particle vector, convert them into integer levels, and then perform power flow calculation and fitness function evaluation in combination with the constraints. After the iteration is completed, the optimal solution of the particle swarm is obtained as the best gear for each SVR in the distribution network, and control commands are issued to drive the corresponding SVR in the distribution network to adjust the gear.

9. A power distribution network voltage regulation resource allocation-operation coordinated control device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-8.

10. A distribution network voltage regulation resource allocation-operation coordinated control system, wherein the system stores a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-8.

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