Electric vehicle cluster voltage support method and device for distribution area

Abstract

The application discloses a power distribution area-oriented electric vehicle cluster voltage support method and device, relates to the technical field of power systems, and comprises the following steps: collecting core parameters of each node to construct a sensitivity matrix, dividing a power distribution area into different response zones, matching a response zone according to a self state and establishing a candidate pool, discharging electric vehicles in the candidate pool when voltage reaches a preset abnormal voltage, and dynamically adjusting discharging power of the electric vehicles and the number of the electric vehicles according to operation data. The application divides different priority weak nodes by constructing a sensitivity matrix, divides response zones in combination with electrical distances, discharges in a targeted manner according to different priority weak nodes and response zones during scheduling, and dynamically adjusts discharging power of the electric vehicles and the number of the electric vehicles by collecting operation data, so that overcompensation or undercompensation is effectively avoided, and resource utilization efficiency and response flexibility and reliability are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method and apparatus for voltage support of electric vehicle clusters in distribution substations. Background Technology

[0002] In recent years, with the rapid increase in the popularity of electric vehicles, the scale of electric vehicle clusters connected to distribution substations has continued to expand. The randomness and volatility of their charging behavior have a significant impact on the voltage stability of the substations. Especially during peak electricity consumption periods, the concentrated charging of a large number of electric vehicles can easily cause voltage drops at substation nodes. Traditional voltage regulation methods, such as transformer tap changer adjustment and reactive power compensation devices, are difficult to adapt to the dynamic voltage fluctuations caused by electric vehicle clusters due to their slow response speed and limited adjustment range. Therefore, achieving voltage support for distribution substations through cluster coordinated discharge has become a key research direction for ensuring the power supply quality of substations.

[0003] In existing technologies, solutions for electric vehicles participating in voltage regulation mostly focus on single-vehicle response or simple cluster control, lacking a fine-grained classification of the voltage weakness of distribution transformer area nodes. This leads to unreasonable allocation of voltage support resources. Some methods do not consider the differences in voltage sensitivity of different nodes, and fail to prioritize the voltage recovery of key weak nodes when scheduling electric vehicle discharge, affecting the overall voltage regulation efficiency. Most solutions do not establish a dynamic adjustment mechanism, and cannot flexibly optimize the discharge power and the number of participants based on real-time voltage changes and the operating status of electric vehicles. This easily leads to overcompensation or undercompensation, making it difficult to adapt to the complex and ever-changing operating environment of distribution transformer areas. Summary of the Invention

[0004] The technical problem solved by this invention is that most solutions for electric vehicles participating in voltage regulation focus on single-vehicle response or simple cluster control, lacking a fine-grained classification of the voltage weakness of distribution transformer area nodes. This leads to unreasonable allocation of voltage support resources. Some methods do not consider the differences in voltage sensitivity of different nodes, and fail to prioritize the voltage recovery of key weak nodes when scheduling electric vehicle discharge, affecting the overall voltage regulation efficiency. Most solutions do not establish a dynamic adjustment mechanism, and cannot flexibly optimize the discharge power and the number of participants according to real-time voltage changes and the operating status of electric vehicles. This easily leads to overcompensation or undercompensation, making it difficult to adapt to the complex and ever-changing operating environment of distribution transformer areas.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for voltage support of electric vehicle clusters in distribution substations, comprising the following steps:

[0006] Step S1: Collect the core parameters of each node to construct a sensitivity matrix, and divide each node into weak nodes with different priorities;

[0007] Step S2: Divide the distribution radio area into different response areas;

[0008] Step S3: Obtain the electric vehicle's own state, match the response area according to the own state, and establish a candidate pool;

[0009] Step S4: When the voltage reaches the preset abnormal voltage, the electric vehicles in the candidate pool are scheduled to discharge.

[0010] Step S5: Collect the voltage of each node and the operating data of the electric vehicle, and dynamically adjust the discharge power of the electric vehicle and the number of electric vehicles based on the operating data.

[0011] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution substations described in this invention, step S1 specifically includes:

[0012] Collect core data from each node in the distribution area, construct a sensitivity matrix using the calculation rules for sensitivity values, obtain the sensitivity values ​​of each node in the sensitivity matrix, and classify each node into weak nodes of different priorities based on the sensitivity values.

[0013] Each node includes a low-voltage outgoing node of a distribution transformer, a branch line connection node, an electric vehicle cluster access node, and a voltage-sensitive load access node.

[0014] The core data includes voltage, current, and impedance parameters;

[0015] The weak nodes with different priorities include high-priority weak nodes, medium-priority weak nodes, and low-priority weak nodes.

[0016] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution substations described in this invention, the step of constructing a sensitivity matrix through the calculation rules of sensitivity values ​​specifically includes:

[0017] The number and connection relationships of all nodes in the distribution substation are obtained to obtain the topology of the distribution substation. The impedance of all lines in the topology is obtained. Based on the relationship that admittance is the reciprocal of impedance, the admittance value of all lines in the topology is calculated. The admittance value is filled into a matrix according to a preset electrical rule to obtain the node admittance matrix. The node admittance matrix is ​​inverted to obtain the node impedance matrix. The correlation between reactive power change and voltage change reflected by the elements in the node impedance matrix is ​​used to obtain the calculation rule for the sensitivity value. The core data of each node is substituted into the calculation rule to obtain the sensitivity value of each node. The sensitivity values ​​are arranged according to the relationship of each node in electrical connection to obtain the sensitivity matrix.

[0018] Obtain the number and connection relationships of all nodes within the distribution transformer area to obtain the topology of the distribution transformer area, and then obtain the impedance parameters of all lines in the topology. ;

[0019] in, Number the nodes. Time represents the line impedance between nodes i and j. The impedance at node i is the self-impedance.

[0020] Based on the reciprocal relationship between admittance and impedance Calculate the admittance values ​​of all lines in the topology. ;

[0021] The admittance values ​​are filled into the matrix according to preset electrical rules to obtain the nodal admittance matrix. The matrix elements are defined as follows:

[0022] Self-admittance ;

[0023] Where n is the total number of nodes, which is the sum of the admittances of all lines connected to node i;

[0024] Mutual admittance ;

[0025] in, That is, the negative value of the line admittance between nodes i and j, and the mutual admittance between non-adjacent nodes is 0;

[0026] The node admittance matrix Matrix inversion operation The node impedance matrix is ​​obtained. ;

[0027] Through the impedance parameters in the node impedance matrix The correlation between reactive power changes and voltage changes is reflected, and the calculation rules for the sensitivity value are determined as follows:

[0028] The formula for calculating the sensitivity value is as follows:

[0029] ;

[0030] in, Let be the sensitivity value of node i. Let i be the voltage at node i. The reactive power of node i;

[0031] The core data voltage of each node and current Substituting the values ​​into the calculation rules, the sensitivity values ​​of each node are obtained. ;

[0032] The sensitivity values ​​are arranged according to the electrical connection relationship of each node to obtain the sensitivity matrix. .

[0033] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution transformer areas described in this invention, the step of dividing each node into weak nodes of different priorities according to the sensitivity value specifically includes:

[0034] Extract the sensitivity values ​​of each node in the sensitivity matrix;

[0035] When the sensitivity value of one of the nodes is greater than or equal to the first threshold, the node is determined to be a high-priority weak node.

[0036] When the sensitivity value of one of the nodes is less than the first threshold and greater than or equal to the second threshold, the node is determined to be a medium-priority weak node.

[0037] When the sensitivity value of one of the nodes is less than the second threshold and greater than or equal to the third threshold, the node is determined to be a low-priority weak node.

[0038] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution substations described in this invention, step S2 specifically includes:

[0039] Based on the high-priority weak node, the electrical distance between each node and the high-priority weak node is obtained, and the distribution radio area is divided into different response areas according to the electrical distance;

[0040] The step of dividing the distribution station area into different response zones based on the electrical distance includes:

[0041] The area surrounding the high-priority weak node that is less than or equal to the first electrical distance threshold is designated as an emergency response zone.

[0042] The region that is greater than the first electrical distance threshold and less than the second electrical distance threshold is divided into a secondary response region;

[0043] The electrical distance includes:

[0044] Using the high-priority weak node as the reference node k, obtain the electrical distance between each node i and the reference node k. ;

[0045] The electrical distance calculation model is as follows:

[0046] ;

[0047] in, Let i be the set of lines on the shortest electrical path from node i to k. , These are the resistance and reactance of the m-th line on the path, respectively;

[0048] Set the first electrical distance threshold ;

[0049] Second electrical distance threshold ;

[0050] Will The area was designated as an emergency response zone;

[0051] Will The area is divided into secondary response zones.

[0052] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution substations described in this invention, step S3 specifically includes:

[0053] The system obtains the state of the electric vehicle itself, filters out electric vehicles that meet the response conditions based on the state of charge and maximum discharge power, matches the electric vehicles that meet the response conditions with the response region based on the electric vehicle's own position, classifies the electric vehicles based on the matched response region, and obtains a candidate pool.

[0054] The self-state includes its own position, state of charge, and maximum discharge power;

[0055] The response conditions include a state of charge greater than a preset state of charge and the electric vehicle's discharge power being less than the maximum discharge power.

[0056] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution substations described in this invention, step S4 specifically includes:

[0057] When the voltage reaches the preset abnormal voltage, the electric vehicles in the scheduling candidate pool are discharged, the voltage deviation between the current voltage and the preset safe voltage is calculated, the sensitivity value of the voltage is calculated according to the sensitivity matrix, and the required compensation power to restore the voltage to the preset safe voltage is obtained by back-calculation of the voltage sensitivity value and voltage deviation value, and the required compensation power is allocated according to the weak nodes with different priorities.

[0058] The electric vehicles in the scheduling candidate pool discharge their batteries, including:

[0059] When the voltage reaches the preset abnormal voltage, the electric vehicles in the emergency response zone whose state of charge is higher than the preset safety threshold are dispatched and discharged at the first preset power.

[0060] If the voltage is lower than the preset safety voltage within a set time period, electric vehicles whose state of charge in the secondary response zone is higher than the preset safety threshold will discharge at the second preset power.

[0061] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution transformer areas described in this invention, the step of allocating the required compensation power according to weak nodes of different priorities specifically includes:

[0062] For high-priority weak nodes, the sensitivity value of the high-priority weak nodes is obtained to obtain a first sensitivity value. The voltage deviation value between the current voltage and the first preset safe voltage is calculated to obtain a first voltage deviation value. The first sensitivity value and the first voltage deviation value are used to calculate the required compensation power to obtain a first compensation power. Based on the first compensation power, the remaining dischargeable electric vehicles in the emergency response area are dispatched from the candidate pool to perform the first round of discharge until the voltage of the high-priority weak nodes is restored to the first preset safe voltage.

[0063] Once the voltage of the high-priority weak node recovers to the first preset safety voltage, for the medium-priority weak node, the sensitivity value of the medium-priority weak node is obtained to obtain the second sensitivity value. The voltage deviation value between the current voltage and the second preset safety voltage is calculated to obtain the second voltage deviation value. The required compensation power is calculated by back-calculating the second sensitivity value and the second voltage deviation value to obtain the second compensation power. Based on the second compensation power, the remaining dischargeable electric vehicles in the secondary response area are scheduled from the candidate pool to perform the second round of discharge until the voltage of the medium-priority weak node recovers to the second preset safety voltage.

[0064] After the voltage of the intermediate priority weak node is restored to the second preset safety voltage, for the low priority weak node, the sensitivity value of the low priority weak node is obtained to obtain the third sensitivity value. The voltage deviation value between the current voltage and the third preset safety voltage is calculated to obtain the third voltage deviation value. The required compensation power is calculated by back-calculating the third sensitivity value and the third voltage deviation value to obtain the third compensation power. According to the third compensation power, the remaining electric vehicles that can be discharged after the first and second rounds of discharge are scheduled from the candidate pool to perform the third round of discharge until the voltage of the low priority weak node is restored to the third preset safety voltage.

[0065] The required compensation power is the sum of the first compensation power, the second compensation power, and the third compensation power.

[0066] As a preferred embodiment of the electric vehicle cluster voltage support method for distribution substations described in this invention, step S5 specifically includes:

[0067] The system collects voltage data at each node and operational data of electric vehicles, including discharge power and remaining battery power. It analyzes the operational data using a sensitivity matrix to obtain voltage recovery information and adjusts the discharge power and number of electric vehicles based on the voltage recovery information.

[0068] If the voltage recovery rate in a certain area is greater than the first preset recovery rate, then the discharge power of electric vehicles in that area with remaining power less than the first preset power threshold will be reduced, and the number of electric vehicles will be reduced.

[0069] If the voltage recovery rate in a certain area is less than the second preset recovery rate, then the discharge power of electric vehicles with remaining power greater than the second preset power threshold in that area will be increased, and the number of electric vehicles will be increased.

[0070] A voltage support device for electric vehicle clusters in a distribution substation area includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, causes the processor to perform the electric vehicle cluster voltage support method for a distribution substation area.

[0071] The beneficial effects of this invention are as follows: By constructing a sensitivity matrix to divide weak nodes with different priorities and combining it with electrical distance to divide response zones, this invention achieves a refined distinction of the voltage weakness of distribution transformer substation nodes, avoiding the problem of unreasonable allocation of voltage support resources. During scheduling, targeted discharge is carried out based on weak nodes with different priorities and response zones, prioritizing the voltage recovery of key weak nodes and improving overall voltage regulation efficiency. By dynamically adjusting the discharge power and number of electric vehicles through the collection of operational data, overcompensation or undercompensation phenomena are effectively avoided, adapting to the complex and ever-changing operating environment of the substation, effectively improving the voltage stability of the distribution transformer substation, taking into account both grid safety and the usage needs of electric vehicles, and significantly improving resource utilization efficiency and response flexibility and reliability. Attached Figure Description

[0072] Figure 1 This is a basic flowchart illustrating a method for providing voltage support for electric vehicle clusters in a distribution substation, as provided in one embodiment of the present invention. Detailed Implementation

[0073] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0074] Example, refer to Figure 1 As an embodiment of the present invention, a method for supporting the voltage of electric vehicle trunking in a distribution substation area is provided, comprising the following steps:

[0075] Step S1: Collect the core parameters of each node to construct a sensitivity matrix, and divide each node into weak nodes with different priorities.

[0076] Step S2: Divide the distribution radio area into different response areas.

[0077] Step S3: Obtain the electric vehicle's own state, match the response area according to the own state, and establish a candidate pool.

[0078] Step S4: When the voltage reaches the preset abnormal voltage, the electric vehicles in the candidate pool are scheduled to discharge.

[0079] Step S5: Collect the voltage of each node and the operating data of the electric vehicles, and dynamically adjust the discharge power of the electric vehicles and the number of electric vehicles based on the operating data.

[0080] Step S1 specifically includes:

[0081] The core data of each node in the distribution area is collected, a sensitivity matrix is ​​constructed according to the calculation rules of the sensitivity value, and the sensitivity value of each node in the sensitivity matrix is ​​obtained. Based on the sensitivity value, each node is divided into weak nodes with different priorities.

[0082] Each node includes the low-voltage outgoing node of the distribution transformer, the branch line connection node, the electric vehicle cluster access node, and the voltage-sensitive load access node.

[0083] The core data includes voltage, current, and impedance parameters.

[0084] Weak nodes of different priorities include high-priority weak nodes, medium-priority weak nodes, and low-priority weak nodes.

[0085] Each node occupies a core or sensitive position in the voltage transmission and distribution of the distribution area. Its voltage status has a significant impact on the overall power supply stability. Core data is the basis for calculating node sensitivity and can intuitively reflect the electrical operating characteristics of the node. Based on the sensitivity value, each node is divided into weak nodes with different priorities, clarifying the importance of different nodes in voltage stability.

[0086] Step S1, by selectively collecting core data and constructing a sensitivity matrix, can accurately quantify the sensitivity of each node to voltage changes, precisely identify weak links prone to voltage anomalies, avoid ineffective analysis of non-critical nodes, improve the accuracy of voltage management, and at the same time, clear priority division can provide clear objectives for subsequent scheduling, ensuring that limited voltage support resources are prioritized for supporting nodes that have the greatest impact on voltage stability, thereby improving resource utilization efficiency and the effectiveness of voltage regulation.

[0087] Constructing a sensitivity matrix based on the rules for calculating sensitivity values ​​specifically includes:

[0088] The process involves obtaining the number and connection relationships of all nodes within the distribution transformer area, thus obtaining the topology of the distribution transformer area. The impedance of all lines in the topology is then obtained. Based on the relationship that admittance is the reciprocal of impedance, the admittance values ​​of all lines in the topology are calculated. These admittance values ​​are then filled into a matrix according to preset electrical rules to obtain the node admittance matrix. The node admittance matrix is ​​then inverted to obtain the node impedance matrix. The correlation between reactive power changes and voltage changes reflected in the elements of the node impedance matrix is ​​used to obtain the calculation rules for sensitivity values. The core data of each node is substituted into the calculation rules to obtain the sensitivity values ​​of each node. Finally, the sensitivity values ​​are arranged according to the electrical connection relationships of each node to obtain the sensitivity matrix.

[0089] Obtain the number and connection relationships of all nodes within the distribution transformer area to obtain the topology of the distribution transformer area, and then obtain the impedance parameters of all lines in the topology. ;

[0090] in, Number the nodes. Time represents the line impedance between nodes i and j. The impedance at node i is the self-impedance.

[0091] Based on the reciprocal relationship between admittance and impedance Calculate the admittance values ​​of all lines in the topology. ;

[0092] The admittance values ​​are filled into the matrix according to preset electrical rules to obtain the nodal admittance matrix. The matrix elements are defined as follows:

[0093] Self-admittance ;

[0094] Where n is the total number of nodes, which is the sum of the admittances of all lines connected to node i;

[0095] Mutual admittance ;

[0096] in, That is, the negative value of the line admittance between nodes i and j, and the mutual admittance between non-adjacent nodes is 0;

[0097] The node admittance matrix Matrix inversion operation The node impedance matrix is ​​obtained. .

[0098] Through the impedance parameters in the node impedance matrix The correlation between reactive power changes and voltage changes is reflected, and the calculation rules for the sensitivity value are determined as follows:

[0099] The formula for calculating the sensitivity value is as follows:

[0100] ;

[0101] in, Let be the sensitivity value of node i. Let i be the voltage at node i. Let i be the reactive power of node i.

[0102] The core data voltage of each node and current Substituting the values ​​into the calculation rules, the sensitivity values ​​of each node are obtained. ;

[0103] The sensitivity values ​​are arranged according to the electrical connection relationship of each node to obtain the sensitivity matrix. .

[0104] The preset electrical rules are based on the connection relationship of nodes in the distribution substation topology. When constructing the node admittance matrix, the self-admittance value of each node is the sum of the admittance values ​​of all lines connected to that node, the mutual admittance value between two adjacent nodes is the negative value of the corresponding connected line admittance value, and the mutual admittance value between non-adjacent nodes is 0. This ensures that the admittance matrix accurately reflects the electrical connection characteristics between each node.

[0105] The correlation law is based on the fundamental relationship between node voltage and reactive power in a power system, namely, there is a linear correlation between the change in node voltage and the change in reactive power. The elements in the node impedance matrix can quantify the degree of this correlation. By analyzing the elements of this matrix, a mathematical expression can be established between the sensitivity value and the changes in reactive power and voltage, thus forming the calculation rules for the sensitivity value.

[0106] The node admittance matrix was obtained by following the standardized calculation process of the electrical characteristics of the power system and the calculation rules for obtaining the sensitivity value, which ensures the scientific nature of the sensitivity quantification. The obtained sensitivity matrix allows the voltage sensitivity characteristics and mutual influence of each node to be presented intuitively.

[0107] Through rigorous electrical matrix calculations, the voltage response characteristics of each node in the distribution transformer area were accurately captured, providing solid theoretical and data support for the calculation of sensitivity values. The constructed sensitivity matrix clearly reflects the electrical connections between nodes and their respective sensitivity to voltage changes, providing accurate and reliable quantitative references for subsequent node priority division and electric vehicle cluster scheduling. This effectively avoids deviations caused by subjective judgments and improves the scientificity and operability of the entire voltage support method.

[0108] Based on sensitivity values, each node is divided into weak nodes of different priorities, specifically including:

[0109] Extract the sensitivity values ​​of each node in the sensitivity matrix.

[0110] When the sensitivity value of one of the nodes is greater than or equal to the first threshold, one of the nodes is determined to be a high-priority weak node.

[0111] When the sensitivity value of one of the nodes is less than the first threshold but greater than or equal to the second threshold, one of the nodes is determined to be a weak node with medium priority.

[0112] When the sensitivity value of one of the nodes is less than the second threshold but greater than or equal to the third threshold, one of the nodes is determined to be a low-priority weak node.

[0113] Based on sensitivity values, each node is divided into weak nodes of different priorities, specifically including:

[0114] Extract the sensitivity values ​​of each node in the sensitivity matrix. .

[0115] Set the first threshold Based on simulation data of load densities of 20-50 kW / km² in typical domestic distribution substations, the sensitivity value corresponding to a voltage drop probability ≥80% is taken, i.e. .

[0116] Set a second threshold Take the sensitivity value corresponding to a voltage drop probability of 30%-80%, i.e. .

[0117] Set a third threshold Take the sensitivity value corresponding to a voltage drop probability ≤ 30%, i.e. .

[0118] when When this happens, the node is determined to be a high-priority weak node.

[0119] when At that time, the node is determined to be a weak node with medium priority.

[0120] when When a node is identified as a low-priority, weak node, it is determined to be vulnerable.

[0121] By using quantitative threshold determination, the vulnerability level of nodes can be accurately classified, avoiding the bias of subjective classification. This allows the voltage support of the subsequent electric vehicle cluster to focus on the high-priority nodes that have the greatest impact on voltage stability, ensuring that limited support resources are used efficiently and improving the pertinence and effectiveness of the entire voltage regulation strategy.

[0122] Step S2 specifically includes:

[0123] Based on the high-priority weak node, the electrical distance between each node and the high-priority weak node is obtained, and the distribution radio area is divided into different response areas according to the electrical distance.

[0124] The distribution area is divided into different response zones based on electrical distance.

[0125] The area around a high-priority weak node that is less than or equal to the first electrical distance threshold is designated as an emergency response zone.

[0126] The region that is greater than the first electrical distance threshold and less than the second electrical distance threshold is divided into the secondary response region.

[0127] Electrical distance includes:

[0128] Using the high-priority weak node as the reference node k, obtain the electrical distance between each node i and the reference node k. ;

[0129] The electrical distance calculation model is as follows:

[0130] ;

[0131] in, Let i be the set of lines on the shortest electrical path from node i to k. , These are the resistance and reactance of the m-th line on the path, respectively.

[0132] Set the first electrical distance threshold ;

[0133] Second electrical distance threshold ;

[0134] Will The area was designated as an emergency response zone;

[0135] Will The area is divided into secondary response zones.

[0136] Set the first electrical distance threshold Based on the PSCAD / EMTDC simulation platform, the electrical distance corresponding to the voltage boost efficiency of electric vehicle discharge on the reference node is selected as ≥0.03 pu / kW.

[0137] Per-unit value standard: Rated voltage of the transformer substation Reference impedance , .

[0138] Values .

[0139] Set a second electrical distance threshold Based on the same simulation verification above, the electrical distance corresponding to the voltage boost efficiency of electric vehicle discharge on the reference node is selected as 0.01-0.03 pu / kW.

[0140] Values .

[0141] The distribution area is divided into different response zones based on electrical distance, including: the area around high-priority weak nodes that is less than or equal to the first electrical distance threshold.

[0142] Right now The area is designated as an emergency response zone.

[0143] It will be greater than the first electrical distance threshold and less than the second electrical distance threshold.

[0144] Right now The area is divided into secondary response zones.

[0145] Electrical distance is not physical distance, but is calculated based on electrical parameters such as impedance and admittance of the distribution substation lines, combined with the power transmission path. It is used to reflect the tightness of electrical connection between nodes. The smaller the distance, the more significant the electrical mutual influence between nodes. The setting of the first electrical distance threshold and the second electrical distance threshold are combined with the topological characteristics of the distribution substation, the actual parameters of the lines, and the response speed requirements of voltage regulation.

[0146] Step S2 divides the response zone by clearly defined electrical distance thresholds, enabling the scheduling of electric vehicles to be carried out in an orderly manner based on the degree of electrical connection with key weak nodes. Electric vehicles in the emergency response zone can participate in discharge first to quickly support the voltage of the core area, while the secondary response zone intervenes as a backup force in a timely manner, improving the timeliness and targeting of voltage support and avoiding the blindness of resource scheduling.

[0147] Step S3 specifically includes:

[0148] The system obtains the state of the electric vehicle itself, filters out electric vehicles that meet the response conditions based on their state of charge and maximum discharge power, matches the electric vehicles that meet the response conditions to the response region based on their own location, classifies the electric vehicles based on the matched response regions, and obtains a candidate pool.

[0149] Its own state includes its own position, state of charge, and maximum discharge power.

[0150] The response conditions include a state of charge greater than the preset state of charge and the electric vehicle's discharge power being less than the maximum discharge power.

[0151] The system can obtain its own location by associating it with the location information of the charging pile or by uploading data through the vehicle's onboard positioning system, ensuring that it can be accurately matched to the corresponding response area and guaranteeing the accuracy of subsequent scheduling.

[0152] Step S3 ensures that electric vehicles in the candidate pool have reliable discharge capabilities and will not be affected by participating in scheduling by screening based on state of charge and maximum discharge power. Classifying by response area enables subsequent scheduling to quickly call vehicles in the corresponding area, improving the efficiency and targeting of voltage support response and providing reliable resource guarantee for accurate and timely voltage regulation.

[0153] Step S4 specifically includes:

[0154] When the voltage reaches the preset abnormal voltage, the electric vehicles in the scheduling candidate pool discharge, calculate the voltage deviation between the current voltage and the preset safe voltage, calculate the voltage sensitivity value based on the sensitivity matrix, and obtain the compensation power required to restore the voltage to the preset safe voltage by back-calculation using the voltage sensitivity value and voltage deviation value, and allocate the required compensation power according to the weak nodes with different priorities.

[0155] Discharging electric vehicles from the candidate pool includes:

[0156] When the voltage reaches the preset abnormal voltage, the electric vehicles in the emergency response zone whose charge state is higher than the preset safety threshold are dispatched to discharge the electric vehicles at the first preset power.

[0157] If the voltage is lower than the preset safety voltage within a set time period, electric vehicles whose state of charge in the secondary response zone is higher than the preset safety threshold will discharge at the second preset power.

[0158] The preset abnormal voltage is set to a critical value that is lower than the normal voltage range and may affect the operation of the equipment. The preset safe voltage is based on the voltage stability requirements of the distribution area to ensure the voltage range for normal operation of the load. The first preset power needs to match the rapid support requirements of the emergency response area for high-priority weak nodes. It is set at 60%-80% of the maximum discharge power of electric vehicles in this area to ensure rapid energy replenishment and avoid battery overload. The second preset power is for the supplementary support of the secondary response area and is set at 40%-60% of the maximum discharge power to form a power gradient with the emergency response area. The setting time is set to 5-15 seconds.

[0159] Step S4 accurately determines the compensation power required to restore the voltage by back-calculating the voltage deviation value and the sensitivity value, avoiding resource waste or insufficient support caused by blind discharge. The scheduling logic of prioritizing the emergency response zone and supplementing the secondary response zone, combined with different preset power discharge, can not only quickly respond to voltage anomalies, but also flexibly adjust according to the voltage recovery situation, ensuring the timeliness and effectiveness of voltage support, while ensuring the orderly discharge of electric vehicles.

[0160] The specific compensation power allocated to weak nodes based on different priorities includes:

[0161] For high-priority weak nodes, obtain the sensitivity value of the high-priority weak nodes to obtain the first sensitivity value, calculate the voltage deviation value between the current voltage and the first preset safety voltage to obtain the first voltage deviation value, and calculate the required compensation power by back-calculating the first sensitivity value and the first voltage deviation value to obtain the first compensation power. According to the first compensation power, dispatch the remaining dischargeable electric vehicles in the emergency response area from the candidate pool to perform the first round of discharge until the voltage of the high-priority weak nodes is restored to the first preset safety voltage.

[0162] Once the voltage of the high-priority weak node recovers to the first preset safety voltage, for the medium-priority weak node, the sensitivity value of the medium-priority weak node is obtained to obtain the second sensitivity value. The voltage deviation value between the current voltage and the second preset safety voltage is calculated to obtain the second voltage deviation value. The required compensation power is calculated by back-calculating the second sensitivity value and the second voltage deviation value to obtain the second compensation power. Based on the second compensation power, the remaining dischargeable electric vehicles in the secondary response area are scheduled from the candidate pool to perform a second round of discharge until the voltage of the medium-priority weak node recovers to the second preset safety voltage.

[0163] After the voltage of the intermediate priority weak node is restored to the second preset safety voltage, for the low priority weak node, the sensitivity value of the low priority weak node is obtained to obtain the third sensitivity value. The voltage deviation value between the current voltage and the third preset safety voltage is calculated to obtain the third voltage deviation value. The required compensation power is calculated by back-calculating the third sensitivity value and the third voltage deviation value to obtain the third compensation power. Based on the third compensation power, the remaining electric vehicles that can be discharged after the first and second rounds of discharge are scheduled from the candidate pool to perform the third round of discharge until the voltage of the low priority weak node is restored to the third preset safety voltage.

[0164] The required compensation power is the sum of the first compensation power, the second compensation power, and the third compensation power.

[0165] The specific formula for calculating the compensation power is based on the sensitivity value, which reflects the linear relationship between the degree of influence of unit reactive power change on voltage and voltage deviation. That is, compensation power = voltage deviation value ÷ sensitivity value, which accurately quantifies the required reactive power compensation.

[0166] By calculating compensation power in a priority-based hierarchical manner and scheduling it sequentially, a tiered and reasonable allocation of limited discharge resources is achieved. This not only prioritizes the high-priority nodes that have the greatest impact on voltage stability, but also avoids power surges through phased discharge. At the same time, the clear definition of the total compensation power makes the total scheduling amount controllable, ensuring that the voltage of each node can be restored in an orderly manner according to priority, thereby improving the systematicness and accuracy of voltage support.

[0167] Step S5 specifically includes:

[0168] The system collects voltage data at each node and operational data of electric vehicles, including discharge power and remaining battery power. It analyzes the operational data using a sensitivity matrix to obtain voltage recovery information and adjusts the discharge power and number of electric vehicles based on the voltage recovery status.

[0169] If the voltage recovery rate in a certain area is greater than the first preset recovery rate, then the discharge power of electric vehicles in that area with remaining power less than the first preset power threshold will be reduced, and the number of electric vehicles will be reduced.

[0170] It prevents the voltage from rising excessively beyond the safe range and protects the batteries of vehicles with low charge from over-discharge.

[0171] If the voltage recovery rate in a certain area is less than the second preset recovery rate, then the discharge power of electric vehicles with remaining power greater than the second preset power threshold in that area will be increased, and the number of electric vehicles will be increased.

[0172] The system collects voltage data at various nodes and operational data from electric vehicles, including discharge power and remaining battery capacity. This operational data is then analyzed using a sensitivity matrix to determine voltage recovery status, which is measured by the voltage recovery speed. , ,unit: .

[0173] Set the first preset recovery speed Based on the requirements of transformer area voltage overshoot control to avoid overshoot exceeding 20% ​​due to excessively rapid voltage recovery, the value is set to... .

[0174] Set the second preset recovery speed Based on the voltage regulation response time requirement, ensure that the voltage returns to a safe range within 30 seconds of an abnormality, with a value of [value missing]. .

[0175] Set the first preset battery threshold Based on lithium battery discharge performance When the discharge power attenuation is >10%, the value is taken as follows: .

[0176] Set a second preset power threshold Based on the battery's remaining charge, it can withstand a discharge power range of 1.1 times the rated power; the value is [value missing]. .

[0177] By analyzing the operational data using a sensitivity matrix, the voltage recovery status can be obtained. By utilizing the quantitative relationship between the node sensitivity values ​​and voltage and power in the sensitivity matrix, the real-time collected electric vehicle discharge power and node voltage data are substituted into the calculation. By comparing the theoretical voltage change with the actual monitored value, it can be determined whether the voltage recovery meets expectations, is too slow, too fast, or normal. At the same time, by combining the node correlation relationship in the matrix, the overall voltage recovery dynamics of the transformer area can be grasped.

[0178] Step S5, by collecting data in real time and combining it with sensitivity matrix analysis, can accurately capture the voltage recovery dynamics and make timely adjustments for situations where the recovery is too fast or too slow. This not only protects the electric vehicle battery but also ensures stable voltage recovery, improving the flexibility and adaptability of the entire control process.

[0179] A voltage support device for electric vehicle clusters in a distribution substation includes a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs a voltage support method for electric vehicle clusters in a distribution substation.

[0180] In one embodiment, a distribution substation containing 7 nodes (nodes 0-6) is selected. First, the line impedance parameters are collected, such as the impedance of line 0-1 being 0.12+j0.09Ω. The node admittance matrix Y is constructed, and the node impedance matrix Z is obtained after inversion. The sensitivity value of each node is calculated according to the formula for calculating the sensitivity value. The results show that node 2 (0.285 pu / Mvar) and node 4 (0.245 pu / Mvar) are high-priority weak nodes.

[0181] Using node 2 as the baseline, calculate the electrical distance. The electrical distances between nodes 1 and 3 and node 2 are 0.39 pu and 0.47 pu, respectively, which are less than the threshold of 0.5 pu. Therefore, nodes 1, 2, and 3 are designated as emergency response zones, and nodes 4, 5, and 6 are designated as secondary response zones.

[0182] The status of electric vehicles is obtained through V2G charging piles, and vehicles with SOC>50% are selected to establish a candidate pool: EV1, EV2, and EV3 are in the emergency response zone; EV4, EV5, etc. are in the secondary response zone.

[0183] The simulated voltage anomaly caused the voltage at node 2 to drop to 0.88 pu. The system calculated that the compensation power required to restore the voltage to 0.94 pu was approximately 210 kVar. EV1, EV2, and EV3 in the emergency response zone were then dispatched to discharge at 70% of their maximum power of 22.4 kW, for a total power of 67.2 kW.

[0184] Ten seconds after the dispatch, the voltage at node 2 rose to 0.93 pu, but did not meet the standard. Then, EV4 and EV5 in the secondary response zone were dispatched to discharge at 50% of their maximum power of 16kW. Within 25 seconds after all dispatch actions were completed, the voltage at node 2 stabilized and recovered to 0.95 pu, and the voltage at node 4 recovered to 0.94 pu, successfully eliminating the voltage anomaly. Moreover, the SOC of all electric vehicles participating in the discharge remained above 30%, effectively avoiding over-discharge.

[0185] This invention constructs a sensitivity matrix to divide weak nodes with different priorities and combines electrical distance to divide response zones, achieving a refined distinction of the voltage weakness of distribution transformer substation nodes. This avoids the problem of unreasonable allocation of voltage support resources. During scheduling, targeted discharge is performed based on weak nodes with different priorities and response zones, prioritizing the voltage recovery of key weak nodes and improving overall voltage regulation efficiency. By collecting operational data, the discharge power and number of electric vehicles are dynamically adjusted, effectively avoiding overcompensation or undercompensation. This adapts to the complex and ever-changing operating environment of distribution transformer substations, effectively improving the voltage stability of distribution transformer substations, balancing grid safety and the needs of electric vehicle use, and significantly improving resource utilization efficiency and response flexibility and reliability.

[0186] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0187] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for supporting the voltage of electric vehicle clusters in a distribution substation area, characterized in that, Includes the following steps: Step S1: Collect the core parameters of each node to construct a sensitivity matrix, and divide each node into weak nodes with different priorities; Step S2: Divide the distribution radio area into different response areas; Step S3: Obtain the electric vehicle's own state, match the response area according to the own state, and establish a candidate pool; Step S4: When the voltage reaches the preset abnormal voltage, the electric vehicles in the candidate pool are scheduled to discharge. Step S5: Collect the voltage of each node and the operating data of the electric vehicle, and dynamically adjust the discharge power of the electric vehicle and the number of electric vehicles based on the operating data; Step S2 specifically includes: Based on the high-priority weak node, the electrical distance between each node and the high-priority weak node is obtained, and the distribution radio area is divided into different response areas according to the electrical distance; The step of dividing the distribution station area into different response zones based on the electrical distance includes: The area surrounding the high-priority weak node that is less than or equal to the first electrical distance threshold is designated as an emergency response zone. The region that is greater than the first electrical distance threshold and less than the second electrical distance threshold is divided into a secondary response region; The electrical distance includes: Using the high-priority weak node as the reference node k, obtain the electrical distance between each node i and the reference node k. ; The electrical distance calculation model is as follows: ； in, Let i be the set of lines on the shortest electrical path from node i to k. , These are the resistance and reactance of the m-th line on the path, respectively; Set the first electrical distance threshold ; Second electrical distance threshold ; Will The area was designated as an emergency response zone; Will The area is divided into secondary response zones.

2. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 1, characterized in that: Step S1 specifically includes: The core data of each node in the distribution area is collected, a sensitivity matrix is ​​constructed according to the calculation rules of the sensitivity value, and the sensitivity value of each node in the sensitivity matrix is ​​obtained. Based on the sensitivity value, each node is divided into weak nodes with different priorities. Each node includes a low-voltage outgoing node of a distribution transformer, a branch line connection node, an electric vehicle cluster access node, and a voltage-sensitive load access node. The core data includes voltage, current, and impedance parameters; The weak nodes with different priorities include high-priority weak nodes, medium-priority weak nodes, and low-priority weak nodes.

3. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 2, characterized in that: The construction of the sensitivity matrix based on the calculation rules of sensitivity values ​​specifically includes: The number and connection relationships of all nodes in the distribution substation are obtained to obtain the topology of the distribution substation. The impedance of all lines in the topology is obtained. Based on the relationship that admittance is the reciprocal of impedance, the admittance value of all lines in the topology is calculated. The admittance value is filled into a matrix according to a preset electrical rule to obtain the node admittance matrix. The node admittance matrix is ​​inverted to obtain the node impedance matrix. The correlation between reactive power change and voltage change reflected by the elements in the node impedance matrix is ​​used to obtain the calculation rule for the sensitivity value. The core data of each node is substituted into the calculation rule to obtain the sensitivity value of each node. The sensitivity values ​​are arranged according to the relationship of each node in electrical connection to obtain the sensitivity matrix. Obtain the number and connection relationships of all nodes within the distribution transformer area to obtain the topology of the distribution transformer area, and then obtain the impedance parameters of all lines in the topology. ; in, Number the nodes. Time represents the line impedance between nodes i and j. The impedance at node i is the self-impedance. Based on the reciprocal relationship between admittance and impedance Calculate the admittance values ​​of all lines in the topology. ; The admittance values ​​are filled into the matrix according to preset electrical rules to obtain the nodal admittance matrix. The matrix elements are defined as follows: Self-admittance ; Where n is the total number of nodes, which is the sum of the admittances of all lines connected to node i; Mutual admittance ; in, That is, the negative value of the line admittance between nodes i and j, and the mutual admittance between non-adjacent nodes is 0; The node admittance matrix Matrix inversion operation The node impedance matrix is ​​obtained. ; Through the impedance parameters in the node impedance matrix The correlation between reactive power changes and voltage changes is reflected, and the calculation rules for the sensitivity value are determined as follows: The formula for calculating the sensitivity value is as follows: ； in, Let be the sensitivity value of node i. Let i be the voltage at node i. The reactive power of node i; The core data voltage of each node and current Substituting the values ​​into the calculation rules, the sensitivity values ​​of each node are obtained. ; The sensitivity values ​​are arranged according to the electrical connection relationship of each node to obtain the sensitivity matrix. .

4. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 2, characterized in that: The step of classifying each node into weak nodes of different priorities based on the sensitivity value specifically includes: Extract the sensitivity values ​​of each node in the sensitivity matrix; When the sensitivity value of one of the nodes is greater than or equal to the first threshold, the node is determined to be a high-priority weak node. When the sensitivity value of one of the nodes is less than the first threshold and greater than or equal to the second threshold, the node is determined to be a medium-priority weak node. When the sensitivity value of one of the nodes is less than the second threshold and greater than or equal to the third threshold, the node is determined to be a low-priority weak node.

5. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 1, characterized in that: Step S3 specifically includes: The system obtains the state of the electric vehicle itself, filters out electric vehicles that meet the response conditions based on the state of charge and maximum discharge power, matches the electric vehicles that meet the response conditions with the response region based on the electric vehicle's own position, classifies the electric vehicles based on the matched response region, and obtains a candidate pool. The self-state includes its own position, state of charge, and maximum discharge power; The response conditions include a state of charge greater than a preset state of charge and the electric vehicle's discharge power being less than the maximum discharge power.

6. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 1, characterized in that: Step S4 specifically includes: When the voltage reaches the preset abnormal voltage, the electric vehicles in the scheduling candidate pool are discharged, the voltage deviation between the current voltage and the preset safe voltage is calculated, the sensitivity value of the voltage is calculated according to the sensitivity matrix, and the voltage sensitivity value and voltage deviation value are back-calculated to obtain the compensation power required to restore the voltage to the preset safe voltage. The required compensation power is allocated according to the weak nodes with different priorities. The electric vehicles in the scheduling candidate pool discharge their batteries, including: When the voltage reaches the preset abnormal voltage, the electric vehicles in the emergency response zone whose state of charge is higher than the preset safety threshold are dispatched and discharged at the first preset power. If the voltage is lower than the preset safety voltage within a set time period, electric vehicles whose state of charge in the secondary response zone is higher than the preset safety threshold will discharge at the second preset power.

7. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 6, characterized in that: The allocation of the required compensation power according to weak nodes of different priorities specifically includes: For high-priority weak nodes, the sensitivity value of the high-priority weak nodes is obtained to obtain a first sensitivity value. The voltage deviation value between the current voltage and the first preset safe voltage is calculated to obtain a first voltage deviation value. The first sensitivity value and the first voltage deviation value are used to calculate the required compensation power to obtain a first compensation power. Based on the first compensation power, the remaining dischargeable electric vehicles in the emergency response area are dispatched from the candidate pool to perform the first round of discharge until the voltage of the high-priority weak nodes is restored to the first preset safe voltage. Once the voltage of the high-priority weak node recovers to the first preset safety voltage, for the medium-priority weak node, the sensitivity value of the medium-priority weak node is obtained to obtain the second sensitivity value. The voltage deviation value between the current voltage and the second preset safety voltage is calculated to obtain the second voltage deviation value. The required compensation power is calculated by back-calculating the second sensitivity value and the second voltage deviation value to obtain the second compensation power. Based on the second compensation power, the remaining dischargeable electric vehicles in the secondary response area are scheduled from the candidate pool to perform the second round of discharge until the voltage of the medium-priority weak node recovers to the second preset safety voltage. After the voltage of the intermediate priority weak node is restored to the second preset safety voltage, for the low priority weak node, the sensitivity value of the low priority weak node is obtained to obtain the third sensitivity value. The voltage deviation value between the current voltage and the third preset safety voltage is calculated to obtain the third voltage deviation value. The required compensation power is calculated by back-calculating the third sensitivity value and the third voltage deviation value to obtain the third compensation power. According to the third compensation power, the remaining electric vehicles that can be discharged after the first and second rounds of discharge are scheduled from the candidate pool to perform the third round of discharge until the voltage of the low priority weak node is restored to the third preset safety voltage. The required compensation power is the sum of the first compensation power, the second compensation power, and the third compensation power.

8. The electric vehicle cluster voltage support method for distribution radio areas as described in claim 1, characterized in that: Step S5 specifically includes: The system collects voltage data at each node and operational data of electric vehicles, including discharge power and remaining battery power. It analyzes the operational data using a sensitivity matrix to obtain voltage recovery information and adjusts the discharge power and number of electric vehicles based on the voltage recovery information. If the voltage recovery rate in a certain area is greater than the first preset recovery rate, then the discharge power of electric vehicles in that area with remaining power less than the first preset power threshold will be reduced, and the number of electric vehicles will be reduced. If the voltage recovery rate in a certain area is less than the second preset recovery rate, then the discharge power of electric vehicles with remaining power greater than the second preset power threshold in that area will be increased, and the number of electric vehicles will be increased.

9. A voltage support device for electric vehicle clusters in a distribution substation area, characterized in that: It includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor causes the processor to perform the electric vehicle cluster voltage support method for distribution radio areas as described in any one of claims 1-8.

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