High-proportion photovoltaic area cooperative control method for DCDC converter

Abstract

The invention provides a high-proportion photovoltaic area cooperative control method for a DCDC converter, and relates to the technical field of electric power supply. The method comprises the following steps: collecting real-time voltage of each DCDC converter node deployed in a photovoltaic transformer area; determining a voltage over-limit node based on the real-time voltage, and constructing a voltage over-limit area based on the voltage over-limit node; for a voltage over-limit node in the voltage over-limit area, determining an influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit area based on the position information of the voltage over-limit node and the real-time voltage; determining an average value of influence coefficients of neighborhood nodes of the voltage over-limit nodes, and recording the average value as a neighborhood influence factor of the voltage over-limit nodes; and determining a key load node based on the neighborhood influence factor and the influence coefficient of the voltage over-limit node and the illumination intensity of the photovoltaic area, and performing reactive compensation on the key load node to adjust the voltage of the voltage over-limit node. According to the invention, the accuracy of screening the key load nodes in the high-proportion photovoltaic transformer area is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and particularly relates to a collaborative control method for a high-proportion photovoltaic substation area for a DCDC converter. Background Art

[0002] Photovoltaic power generation refers to a power generation technology that converts light energy into electrical energy based on the photovoltaic effect. As a form of new energy power generation, it has been widely used. A DC-DC converter (DCDC converter), as an important device in the field of photovoltaic power generation, is an electronic device or circuit module that converts a DC voltage into another fixed or adjustable DC voltage. In a high-proportion photovoltaic substation area (where the proportion of photovoltaic power generation output in the total load of the substation area is close to or exceeds 50%), the DCDC converter can improve voltage stability and power quality through means such as boost conversion and voltage regulation control. In practical applications, since photovoltaic power generation depends on the photovoltaic effect after light irradiates semiconductors to convert light energy into electrical energy, and light irradiation is significantly affected by external environmental factors such as climate, weather, and geography, and as the proportion of the photovoltaic system increases, voltage fluctuations in different regions may affect the voltage in other regions, resulting in a greater working pressure on the DCDC converters at some locations with larger voltage changes and prone to voltage over-limit phenomena.

[0003] Related technologies usually solve the above problems through the following methods: sorting the DCDC converter nodes in the substation area according to the degree of voltage over-limit of the nodes in the substation area topology network, and selecting the DCDC converter node with the largest degree of voltage over-limit as the key load node; performing reactive power compensation on the key load node through a photovoltaic inverter to solve the voltage over-limit problem. [[ID=,12]]

[0004] However, since photovoltaic power generation is related to factors such as weather and sunlight intensity, and there are complex interdependencies between nodes in the distribution network, a simple sorting of the degree of voltage over-limit is not sufficient to accurately identify the key load nodes, thereby affecting the pertinence and accuracy of voltage regulation. Summary of the Invention

[0005] In view of this, the embodiments of the present disclosure propose a collaborative control method for a high-proportion photovoltaic substation area for a DCDC converter to solve the problem in related technologies that a simple sorting of the degree of voltage over-limit is not sufficient to accurately identify the key load nodes, thereby affecting the pertinence and accuracy of voltage regulation.

[0006] According to the first aspect of the present disclosure, a collaborative control method for a high-proportion photovoltaic substation area for a DCDC converter is provided, and the specific technical solution adopted is as follows: Collect the node operation data of each node in the photovoltaic substation area; the node is the DCDC converter in the photovoltaic substation area, and the node operation data includes the real-time voltage; Determine the voltage over-limit nodes in the nodes based on the real-time voltage, and construct a voltage over-limit area based on the voltage over-limit nodes; For each of the voltage over-limit nodes in the voltage over-limit area, determine the influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit area based on the position information of the voltage over-limit node and the real-time voltage; Determine the neighborhood nodes connected to the voltage over-limit node in the voltage over-limit area, and calculate the average value of the influence coefficients of each of the neighborhood nodes, which is denoted as the neighborhood influence factor of the voltage over-limit node; Based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic substation area, determine the critical load nodes in the voltage over-limit nodes, and perform reactive power compensation on the critical load nodes to adjust the voltage of the voltage over-limit nodes.

[0007] Exemplarily, the determining the voltage over-limit nodes in the nodes based on the real-time voltage and constructing a voltage over-limit area based on the voltage over-limit nodes includes: obtaining the rated voltage of each power device on the nodes, and determining the normal voltage of the nodes based on the rated voltage; obtaining the real-time voltage of the nodes collected at the current moment, and calculating the difference between the real-time voltage at the current moment and the normal voltage of the nodes, which is denoted as the voltage over-limit degree of the nodes; determining the nodes with the voltage over-limit degree greater than the first preset threshold as the abnormal nodes at the current moment; for each of the abnormal nodes at the current moment, obtaining the real-time voltage of the abnormal node collected at the historical moment, and determining the abnormal frequency of the abnormal node being marked as abnormal at the historical moment based on the real-time voltage at each historical moment and the normal voltage of the abnormal node; determining the abnormal nodes at the current moment with the abnormal frequency greater than the second preset threshold as the voltage over-limit nodes; constructing the voltage over-limit area according to the distribution of each voltage over-limit node in the photovoltaic substation area.

[0008] Exemplarily, for each of the voltage over-limit nodes in the voltage over-limit area, based on the position information of the voltage over-limit node and the real-time voltage, determining the influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit area includes: determining the current voltage over-limit node in the voltage over-limit area, and determining the distance levels of the other nodes according to the topological distance between the current voltage over-limit node and the other nodes in the distribution topology network of the photovoltaic station area; at each of the distance levels, based on the physical distance between the current voltage over-limit node and each of the other nodes at the distance level, determining the distance correlation of the current voltage over-limit node at the distance level; based on the difference in the real-time voltage of the current voltage over-limit node at adjacent historical moments, determining the first voltage change amplitude sequence corresponding to the current voltage over-limit node; at each of the distance levels, based on the difference in the real-time voltage of the other nodes at adjacent historical moments, determining the second voltage change amplitude sequence corresponding to the other nodes, and determining the voltage correlation of the current voltage over-limit node at the distance level based on the first voltage change amplitude sequence and the second voltage change amplitude sequence; according to the distance correlation and the voltage correlation between the current voltage over-limit node and the other nodes at each of the distance levels, determining the influence coefficient corresponding to the current voltage over-limit node.

[0009] Exemplarily, the determining the distance correlation of the current voltage over-limit node at the distance level based on the physical distance between the current voltage over-limit node and each of the other nodes at the distance level includes: for each of the other nodes at the distance level, calculating the Euclidean distance between the other node and the current voltage over-limit node, and determining the node distance correlation between the current voltage over-limit node and the other node based on the Euclidean distance and the topological distance corresponding to the distance level; calculating the average value of the node distance correlations at the distance level, and denoting it as the distance correlation of the current voltage over-limit node at the distance level.

[0010] Exemplarily, the determining the voltage correlation of the current voltage over-limit node at the distance level based on the first voltage change amplitude sequence and the second voltage change amplitude sequence includes: calculating the Pearson correlation coefficient between the first voltage change amplitude sequence and each of the second voltage change amplitude sequences; calculating the average value of the Pearson correlation coefficients at the distance level, and denoting it as the voltage correlation of the current voltage over-limit node at the distance level.

[0011] Exemplarily, determining the influence coefficient corresponding to the current voltage over-limit node according to the distance correlation and the voltage correlation between the current voltage over-limit node and the other nodes at each distance level includes: calculating the average value of the product of the distance correlation and the voltage correlation at each distance level, and denoting it as the initial influence coefficient corresponding to the current voltage over-limit node; determining the regional voltage over-limit degree of the voltage over-limit area based on the voltage over-limit degrees of the voltage over-limit nodes in the voltage over-limit area; and determining the influence coefficient corresponding to the current voltage over-limit node based on the voltage over-limit degree of the current voltage over-limit node, the regional voltage over-limit degree, and the initial influence coefficient.

[0012] Exemplarily, determining the critical load nodes among the voltage over-limit nodes based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic substation area includes: determining the environmental influence factor of the voltage over-limit node based on the light intensity and the photovoltaic ratio of the photovoltaic substation area; determining the critical load index of the voltage over-limit node based on the neighborhood influence factor, the environmental influence factor, and the influence coefficient of the voltage over-limit node, and determining the voltage over-limit node with the critical load index greater than the third preset threshold as the critical load node.

[0013] Exemplarily, determining the critical load index of the voltage over-limit node based on the neighborhood influence factor, the environmental influence factor, and the influence coefficient of the voltage over-limit node includes: calculating the product of the reciprocal of the neighborhood influence factor and the environmental influence factor, and denoting it as the load correction coefficient; calculating the product of the load correction coefficient, the influence coefficient of the voltage over-limit node, and the voltage over-limit degree of the voltage over-limit node, and denoting it as the critical load index of the voltage over-limit node.

[0014] Exemplarily, performing reactive power compensation on the critical load nodes includes: determining the sensitivity coefficient of each photovoltaic node in the photovoltaic substation area with respect to the critical load node; where the sensitivity coefficient is used to characterize the influence degree of the unit reactive power change of the photovoltaic node on the voltage of the critical load node; sorting the photovoltaic nodes based on the sensitivity coefficient, and determining the target compensation device in the photovoltaic inverters corresponding to the photovoltaic nodes based on the sorting result; calculating the reactive power compensation amount required by the critical load node through the intelligent distribution transformer terminal, and generating a corresponding control instruction; and sending the control instruction to the target compensation device to achieve reactive power compensation for the critical load node through the target compensation device.

[0015] Exemplarily, the reactive power compensation for the critical load nodes further includes: after performing reactive power compensation on the critical load nodes, obtaining the real-time voltage of each node in the photovoltaic substation area, and determining whether there are voltage over-limit nodes in the photovoltaic substation area based on the real-time voltage; if there are voltage over-limit nodes, determining the target compensation device for the voltage over-limit nodes, and performing reactive power compensation on the voltage over-limit nodes based on the target compensation device until there are no voltage over-limit nodes in the photovoltaic substation area.

[0016] The present invention may have the following partial or full beneficial effects: In the high-proportion photovoltaic substation area collaborative control method for DCDC converters provided by the present invention, after determining the voltage over-limit nodes based on the real-time voltage of each DCDC converter node and constructing the voltage over-limit area, the influence coefficient of each voltage over-limit node on other nodes is further determined through the position information of the voltage over-limit nodes. Therefore, in the process of determining the critical load nodes, the mutual dependence relationship between nodes can be taken into account through this influence coefficient, improving the accuracy of the selected critical load nodes; at the same time, in the process of determining the critical load nodes, the present invention also introduces the factor of light intensity. By comprehensively considering environmental factors, the connection between nodes, and the degree of voltage over-limit, the problem of inaccurate selection of critical load nodes caused by simply sorting according to the degree of voltage over-limit in the traditional method is avoided; in addition, the present invention can also perform reactive power regulation on the identified critical load nodes, reduce the voltage over-limit phenomenon caused by the randomness and volatility of photovoltaic power generation output, enhance the stability of the power grid in the face of environmental factor disturbances such as changes in light intensity, and avoid equipment damage and power outages caused by abnormal voltages.

[0017] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 Shows a flowchart of a high-proportion photovoltaic substation area collaborative control method for DCDC converters according to an exemplary embodiment of the present disclosure; Figure 2 Shows a schematic block diagram of a high-proportion photovoltaic substation area collaborative control device for DCDC converters according to an exemplary embodiment of the present disclosure. Specific Embodiment

[0020] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following specifically describes, with reference to the accompanying drawings and preferred embodiments, the specific embodiment, structure, features, and effects of the high-proportion photovoltaic substation area collaborative control method for a DCDC converter proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0022] The following specifically describes the specific solution of the high-proportion photovoltaic substation area collaborative control method for a DCDC converter provided by the present invention with reference to the accompanying drawings.

[0023] Please refer to Figure 1 , which shows the method flow chart of the high-proportion photovoltaic substation area collaborative control method for a DCDC converter provided by an embodiment of the present invention. As Figure 1 shown, the high-proportion photovoltaic substation area collaborative control method for a DCDC converter specifically includes the following steps: S110: Collect the node operation data of each node in the photovoltaic substation area; the above nodes are DCDC converters deployed in the photovoltaic substation area, and the node operation data includes the real-time voltage; S120: Determine the voltage over-limit nodes among the above nodes based on the real-time voltage, and construct a voltage over-limit area based on the voltage over-limit nodes; S130: For each voltage over-limit node in the voltage over-limit area, determine the influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit area based on the position information and real-time voltage of the voltage over-limit node; S140: Determine the neighborhood nodes connected to the voltage over-limit nodes in the voltage over-limit area, calculate the average value of the influence coefficients of each neighborhood node, and denote it as the neighborhood influence factor of the voltage over-limit node; S150: Determine the critical load nodes among the voltage over-limit nodes based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic substation area, and perform reactive power compensation on the critical load nodes to adjust the voltage of the voltage over-limit nodes.

[0024] The following details each step of the above high-proportion photovoltaic substation area collaborative control method for a DCDC converter: In step S110, node operation data of each node in the photovoltaic substation area is collected; the above nodes are DCDC converters deployed in the photovoltaic substation area, and the node operation data includes real-time voltage.

[0025] In the embodiment of the present application, the above photovoltaic substation area refers to a distribution network substation area connected to a photovoltaic power generation system; wherein, the above distribution network substation area is the basic unit of the distribution network in the power system, usually referring to the power supply area from the low-voltage side of the distribution transformer to the user side, responsible for converting medium-voltage electric energy into low-voltage electric energy and distributing it to various users; the photovoltaic substation area targeted by the high-proportion photovoltaic substation area collaborative control method for DCDC converters provided in the embodiment of the present application is a high-proportion photovoltaic substation area, that is, a distribution network substation area where the proportion of photovoltaic power generation output to the total load is close to or exceeds 50%.

[0026] In the embodiment of the present application, the above nodes refer to DCDC converters deployed in the photovoltaic substation area. The DCDC converter is an electronic device or circuit module that converts a DC voltage into another fixed or adjustable DC voltage. In a high-proportion photovoltaic substation area, the DCDC converter can improve voltage stability and power quality through means such as boost conversion and voltage stabilization control. Exemplarily, the above DCDC converters can be distributed in various places such as factories, schools, and hospitals.

[0027] In the embodiment of the present application, the above node operation data is data used to characterize the status of the corresponding node. Exemplarily, the node operation data can include electrical quantities, status quantities, and non-electrical quantities of each node; wherein, the above electrical quantities can include data such as high / low voltage side voltage, current, power (active, reactive, apparent, etc.), power factor, frequency, etc.; the above status quantities can include data such as switch position status (circuit breaker, load switch, disconnecting switch), protection action signal, energy storage status, etc.; the above non-electrical quantities can include data such as transformer oil temperature, winding temperature, ambient temperature and humidity, access control status, water immersion status, partial discharge signal, etc.

[0028] In the embodiment of the present application, the above collection of node operation data of each node in the photovoltaic substation area can be realized through an intelligent distribution transformer terminal system. The intelligent distribution transformer terminal system includes various modules such as a main control unit, a data collection unit, and a communication module; wherein, the data collection unit of the intelligent distribution transformer terminal system integrates various sensors, so data such as electrical quantities, status quantities, and non-electrical quantities of the above nodes can be collected through each sensor in the data collection unit.

[0029] In an embodiment of the present application, after the above-mentioned node operation data is collected by the intelligent distribution transformer terminal system, the collected data can be preprocessed and stored in the intelligent distribution transformer terminal system. At the same time, data interaction is carried out with the master station system and other on-site devices (such as feeder terminal units, fault indicators, etc.) through the communication module. Among them, the above-mentioned preprocessing can include removing noise, outliers and format differences in the collected node operation data to ensure the accuracy of subsequent voltage over-limit analysis and node association calculation.

[0030] In step S120, based on the real-time voltage, determine the voltage over-limit nodes among the above-mentioned nodes, and construct a voltage over-limit area based on the voltage over-limit nodes.

[0031] In an embodiment of the present application, the above-mentioned voltage over-limit node refers to a distribution node in the above-mentioned high-proportion photovoltaic substation area, where the degree of deviation of the real-time voltage at the current moment from its normal voltage exceeds a preset threshold, and voltage anomalies frequently occur during historical operation.

[0032] In an embodiment of the present application, the above-mentioned voltage over-limit area is a continuous area formed by multiple above-mentioned voltage over-limit nodes in the distribution topology network, and there is a significant correlation between the voltage fluctuations of the voltage over-limit nodes within the voltage over-limit area.

[0033] Exemplarily, the above-mentioned determination of the voltage over-limit nodes in the nodes based on the real-time voltage and the construction of the voltage over-limit area based on the voltage over-limit nodes can be achieved as follows: obtain the rated voltage of each power device on the node, and determine the normal voltage of the node based on the rated voltage; obtain the real-time voltage of the node collected at the current moment, and calculate the difference between the real-time voltage at the current moment and the normal voltage of the node, which is recorded as the voltage over-limit degree of the node; determine the nodes with a voltage over-limit degree greater than the first preset threshold as the abnormal nodes at the current moment; for each abnormal node at the current moment, obtain the real-time voltage of the abnormal node collected at historical moments, and based on the real-time voltages at each historical moment and the normal voltage of the abnormal node, determine the abnormal frequency of the abnormal node being marked as abnormal at historical moments; determine the abnormal nodes at the current moment with an abnormal frequency greater than the second preset threshold as the voltage over-limit nodes; construct a voltage over-limit area according to the distribution of each voltage over-limit node in the photovoltaic substation area.

[0034] In the embodiments of the present application, the above-mentioned rated voltage refers to the standard voltage value designed for the corresponding power equipment (such as transformers, motors, lighting devices, etc.) under normal operating conditions, which is a basic parameter for the safe operation of the equipment; the above-mentioned normal voltage is the reference voltage value of the corresponding node in the distribution network substation area under normal operating conditions. Exemplarily, the normal voltage can be determined by the rated voltages of the power equipment under the corresponding node. Specifically, if there is only one power equipment under the node, the normal voltage of the node is taken as the rated voltage of the power equipment; if there are multiple power equipment under the node, the value of the normal voltage of the node needs to be greater than the maximum rated voltage among the multiple power equipment.

[0035] In the embodiments of the present application, the above-mentioned voltage over-limit degree is an index used to characterize the deviation degree of the real-time voltage of the node relative to the normal voltage. Specifically, taking the i-th node in the photovoltaic substation area at time t as an example, the voltage over-limit degree of the i-th node at time t can be calculated by the following formula: , where, is the voltage over-limit degree of the i-th node at time t; is the real-time voltage of the i-th node at time t; is the normal voltage of the i-th node; is a normalization function; When the value of is positive, it proves that the real-time voltage of the node exceeds the normal voltage. When the value of is negative, it proves that the real-time voltage of the node is lower than the normal voltage. The above two states both belong to the voltage over-limit state. The voltage over-limit degree of the node in the voltage over-limit state is obtained by taking the absolute value of.

[0036] In the embodiments of the present application, the above-mentioned historical moment refers to the moment included in a period of time before the current moment. Exemplarily, the real-time voltages of each node collected in step S110 before the current moment are all historical data collected at historical moments.

[0037] Further, for each node in the photovoltaic substation area, in the embodiments of the present application, the voltage over-limit degree of each node at the current moment and multiple historical moments can be calculated in the same way through the above formula for calculating the voltage over-limit degree of the i-th node at the t-th moment, and the voltage over-limit nodes can be determined based on the calculated voltage over-limit degree. The specific implementation can be as follows: Taking the above first preset threshold as 0.25 as an example, all nodes with a voltage over-limit degree greater than 0.25 at the current moment are screened out, and the screened nodes are recorded as abnormal nodes at the current moment; for each abnormal node screened out at the current moment, the frequency of being marked as abnormal at historical moments for each abnormal node is counted. Exemplarily, the abnormal frequency can be determined by the number of historical moments when the voltage over-limit degree of the abnormal node is greater than 0.25. Taking the i-th node being determined as an abnormal node at the current moment as an example, the specific calculation formula can be as follows: , wherein, is the abnormal frequency of the i-th abnormal node being marked as abnormal at historical moments; is the number of times the i-th abnormal node is marked as an abnormal node at historical moments (i.e., the number of historical moments when the voltage over-limit degree of the i-th abnormal node is greater than 0.25); is the total number of data acquisition moments up to the current moment.

[0038] Taking the above second preset threshold as 0.3 as an example, if the frequency of a certain abnormal node at the current moment being marked as an abnormal node at historical moments is greater than 0.3, then it is determined that the abnormal node is a voltage over-limit node; specifically, taking the i-th node being determined as an abnormal node at the current moment as an example, if the calculated , then it is determined that the i-th abnormal node is a voltage over-limit node.

[0039] In the embodiments of the present application, after determining the voltage over-limit nodes in the photovoltaic substation area through the above process, a voltage over-limit area can also be constructed according to the positions of the voltage over-limit nodes. Specifically, in the process of constructing the voltage over-limit area, taking the t-th moment as the current moment as an example, if the number of normal nodes between the i-th voltage over-limit node and the i + 1-th voltage over-limit node is less than , then it is determined that the i-th voltage over-limit node and the i + 1-th voltage over-limit node belong to the same voltage over-limit area, and the normal nodes between them are also included in the voltage over-limit area; conversely, if the number of normal nodes between the i-th voltage over-limit node and the i + 1-th voltage over-limit node is greater than , then it is determined that the i-th voltage over-limit node and the i + 1-th voltage over-limit node do not belong to the same voltage over-limit area; wherein, the above is the voltage over-limit degree of the i-th voltage over-limit node at the t-th moment, and the above is the degree of voltage over - limit of the (i + 1)-th voltage over - limit node at time t.

[0040] In step S130, for each voltage over - limit node in the voltage over - limit area, based on the position information and real - time voltage of the voltage over - limit node, the influence coefficient of the voltage over - limit node on other nodes in the voltage over - limit area is determined.

[0041] In the embodiment of the present application, the above - mentioned position information of the voltage over - limit node is geometric and topological parameters used to characterize the spatial distribution and mutual relationship of the voltage over - limit node in the distribution topology network. Exemplarily, the above - mentioned position information may include the topological distance and physical distance between the voltage over - limit node and other nodes; among them, the above - mentioned topological distance refers to the connection path length between the voltage over - limit node and other nodes in the distribution topology network, which is used to measure the electrical connection tightness between nodes. For example, if a voltage over - limit node is directly connected to the PV connection point, the topological distance between the voltage over - limit node and the PV connection point is 1, and its voltage fluctuation is more directly affected by the PV; the above - mentioned physical distance is the straight - line distance between the voltage over - limit node and other nodes in the actual geographical space, which is used to correct the limitation of the topological distance (for example, topologically adjacent nodes may be far apart in actual distance. At this time, the conduction of voltage fluctuation is more affected by the line impedance, and the correlation between nodes is weak).

[0042] In the embodiment of the present application, the above - mentioned influence coefficient is an index used to quantify the degree of voltage fluctuation influence of the voltage over - limit node on other nodes in the voltage over - limit area where it is located.

[0043] Exemplarily, for each voltage over - limit node in the voltage over - limit area, based on the position information and real - time voltage of the voltage over - limit node, the determination of the influence coefficient of the voltage over - limit node on other nodes in the voltage over - limit area can be achieved as follows: Determine the current voltage over - limit node in the voltage over - limit area, and determine the distance levels of other nodes according to the topological distance between the current voltage over - limit node and other nodes in the distribution topology network of the PV sub - station area; at each distance level, based on the physical distance between the current voltage over - limit node and other nodes at each distance level, determine the distance correlation of the current voltage over - limit node at each distance level; based on the difference in the real - time voltage of the current voltage over - limit node at adjacent historical moments, determine the first voltage change amplitude sequence corresponding to the current voltage over - limit node; at each distance level, based on the difference in the real - time voltage of other nodes at adjacent historical moments, determine the second voltage change amplitude sequence corresponding to other nodes, and determine the voltage correlation of the current voltage over - limit node at the distance level based on the first voltage change amplitude sequence and the second voltage change amplitude sequence; according to the distance correlation and voltage correlation between the current voltage over - limit node and other nodes at each distance level, determine the influence coefficient corresponding to the current voltage over - limit node.

[0044] In the embodiments of the present application, the PV grid connection point is the location where the PV system delivers power to the distribution network. The closer the physical distance between the voltage over-limit node and the PV grid connection point, the deeper the degree of its influence by PV power generation. Therefore, when determining the critical load nodes, it is preferred to consider the voltage over-limit nodes close to the PV grid connection point. Exemplarily, the above determination of the current voltage over-limit nodes in the voltage over-limit area can be achieved as follows: Sort the voltage over-limit nodes in the voltage over-limit area according to the physical distance between each voltage over-limit node and the PV grid connection point, and sequentially determine each voltage over-limit node in the voltage over-limit area as the current voltage over-limit node in the order from near to far, and determine the influence coefficient of the current voltage over-limit node on other nodes in the voltage over-limit area.

[0045] After determining the current voltage over-limit node, taking the current voltage over-limit node as the k-th node in the voltage over-limit area as an example, the above determination of the distance levels of other nodes in the voltage over-limit area can be achieved as follows: Obtain the shortest topological distance between other nodes in the voltage over-limit area and the k-th node, and determine the distance level of the corresponding node according to the shortest topological distance. Exemplarily, the nodes with the shortest topological distance of 1 from the k-th node are divided into the first distance level, the nodes with the shortest topological distance of 2 from the k-th node are divided into the second distance level, and so on, and all other nodes in the voltage over-limit area except the k-th node are divided into the corresponding distance levels.

[0046] In the embodiments of the present application, the above distance correlation is used to characterize the influence degree of the spatial distance between the current voltage over-limit node and other nodes in the distribution topology network on the voltage fluctuation correlation between the two. The larger the value of the distance correlation, the closer the corresponding node is to the current voltage over-limit node, and the more significant the influence of its voltage change by the current voltage over-limit node.

[0047] Exemplarily, the above determination of the distance correlation of the current voltage over-limit node at each distance level based on the physical distance between the current voltage over-limit node and other nodes at each distance level can be achieved as follows: For each other node at the current distance level, calculate the Euclidean distance between each other node and the current voltage over-limit node, and determine the node distance correlation between the current voltage over-limit node and each other node based on the Euclidean distance and the topological distance corresponding to the current distance level; Calculate the average value of the node distance correlations at the current distance level, and denote it as the distance correlation of the current voltage over-limit node at the current distance level.

[0048] Specifically, taking the current voltage over-limit node as the k-th node in the voltage over-limit area as an example, for another node which is the v-th node at the r-th distance level, calculating the node distance correlation between the current voltage over-limit node and this other node can be achieved as follows: Calculate the Euclidean distance between the v-th node at the r-th distance level and the k-th node , and calculate the node distance correlation between the k-th node and the v-th node at the r-th distance level through the following formula: , wherein, is the node distance correlation between the k-th node and the v-th node at the r-th distance level; the above r is the topological distance between the k-th node and the v-th node at the r-th distance level; the above is the Euclidean distance between the k-th node and the v-th node at the r-th distance level; is the normalization function.

[0049] Similarly, the node distance correlations between the current voltage over-limit node and all other nodes in the voltage over-limit area can be determined. Further, for each node at the same distance level, calculate the average value of the node distance correlations between each node at this distance level and the current voltage over-limit node, and denote it as the distance correlation of the current voltage over-limit node at this distance level.

[0050] In the embodiments of the present application, the above voltage correlation is an index used to quantify the voltage fluctuation correlation between the voltage over-limit node and other nodes; the above first voltage change amplitude sequence is used to characterize the voltage fluctuation condition of the corresponding voltage over-limit node. Specifically, this first voltage change amplitude sequence can be obtained through the following steps: Obtain the real-time voltage of the voltage over-limit node within a historical time period (such as the past 3 months); calculate the difference between the real-time voltages of the voltage over-limit node at adjacent moments, and denote it as the voltage change amplitude between these two adjacent moments. Taking the (t - 1)-th moment and the t-th moment as an example, the voltage change amplitude of the i-th voltage over-limit node between these two moments , wherein, is the real-time voltage of the i-th voltage over-limit node at the t-th moment, the real-time voltage of the i-th voltage over-limit node at the (t - 1)-th moment; Denote the sequence composed of the voltage change amplitudes at adjacent moments within the historical time period as the above first voltage change amplitude sequence. Similarly, the second voltage change amplitude sequence of other nodes in the voltage over-limit area can be obtained.

[0051] Exemplarily, the process of determining the voltage correlation of the above-mentioned current voltage over-limit node at a certain distance level can be implemented as follows: Calculate the Pearson correlation coefficients between the first voltage change amplitude sequence and each second voltage change amplitude sequence; Calculate the average value of the Pearson correlation coefficients at the distance level, denoted as the voltage correlation of the current voltage over-limit node at the distance level. Specifically, taking the r-th distance level as an example, determine the first voltage change amplitude sequence corresponding to the current voltage over-limit node, and each second voltage change amplitude sequence corresponding to other nodes divided into the r-th distance level, and calculate the Pearson correlation coefficients between the first voltage change amplitude sequence and each second voltage change amplitude sequence. Taking the above-mentioned current voltage over-limit node as the k-th node as an example, for the v-th node at the r-th distance level, calculate the Pearson correlation coefficient between the first voltage change amplitude sequence of the k-th node and the second voltage change amplitude sequence of the v-th node at the r-th distance level , the Pearson correlation coefficient The larger it is, the more similar the voltage change trends of the k-th node and the v-th node at the r-th distance level are. For example, the voltage rises or falls simultaneously, and the change amplitudes are similar; Calculate the average value of the Pearson correlation coefficients between the k-th node and each node at the r-th distance level, denoted as the voltage correlation of the k-th node at the r-th distance level .

[0052] After determining the distance correlation and voltage correlation of the current voltage over-limit node at each distance level through the above process, exemplarily, the above-mentioned method of determining the influence coefficient corresponding to the current voltage over-limit node according to the distance correlation and voltage correlation between the current voltage over-limit node and other nodes at each distance level can be implemented as follows: Calculate the average value of the product of the distance correlation and voltage correlation at each distance level, denoted as the initial influence coefficient corresponding to the current voltage over-limit node; Based on the voltage over-limit degree of each voltage over-limit node in the voltage over-limit area, determine the regional voltage over-limit degree of the voltage over-limit area; Based on the voltage over-limit degree of the current voltage over-limit node, the regional voltage over-limit degree and the initial influence coefficient, determine the influence coefficient corresponding to the current voltage over-limit node.

[0053] In the embodiments of the present application, the above-mentioned regional voltage over-limit degree is a key index for comprehensively evaluating the overall voltage stability of the region by quantifying the deviation of the real-time voltage of all nodes in the voltage over-limit area from the normal voltage.

[0054] Specifically, taking the current voltage over-limit node as the k-th node in the voltage over-limit area as an example, assuming that the voltage over-limit area to which the k-th node belongs is the j-th voltage over-limit area, the regional voltage over-limit degree of the j-th voltage over-limit area can be calculated by the following formula: , Among them, is the degree of regional voltage over-limit of the j-th voltage over-limit area; is the degree of voltage over-limit of the i-th node in the j-th voltage over-limit area; is the number of nodes included in the j-th voltage over-limit area.

[0055] The specific initial influence coefficient corresponding to the k-th node above can be calculated through the following formula: , Among them, is the influence coefficient of the k-th node on other nodes in the voltage over-limit area; is the distance correlation of the k-th node at the r-th distance level; is the voltage correlation of the k-th node at the r-th distance level; is the total number of distance levels divided under the k-th node.

[0056] Furthermore, the influence coefficient of the k-th node above can be calculated through the following formula: , Among them, is the influence coefficient of the k-th node on other nodes in the voltage over-limit area; is the degree of voltage over-limit of the k-th node; is the degree of regional voltage over-limit of the j-th voltage over-limit area where the k-th node is located; is the initial influence coefficient corresponding to the k-th node; is the normalization function.

[0057] In step S140, determine the neighborhood nodes connected to the voltage over-limit node in the voltage over-limit area, and calculate the average value of the influence coefficients of each neighborhood node, which is denoted as the neighborhood influence factor of the voltage over-limit node.

[0058] Exemplarily, taking the current voltage over-limit node as the k-th node in the voltage over-limit area, the above neighborhood influence factor can be determined by the following method: for the k-th node, determine the neighborhood nodes adjacent to the k-th node; calculate the influence coefficients of each neighborhood node on other nodes in the voltage over-limit area and take the average, which is denoted as the neighborhood influence factor of the k-th node ; the larger the neighborhood influence factor of the k-th node, the stronger the influence degree of the k-th node by the voltage fluctuations of its surrounding nodes, and the greater the possibility that the k-th node is a false critical load node; among them, the above false critical load node refers to the voltage over-limit node caused by the existence of multiple nodes with relatively high influence coefficients in its neighborhood when the light intensity is relatively high and the photovoltaic proportion of the distribution network is relatively large.

[0059] In step S150, based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic area, the critical load nodes in the voltage over-limit nodes are determined, and reactive power compensation is performed on the critical load nodes to regulate the voltage of the voltage over-limit nodes.

[0060] In the embodiment of the present application, the above critical load nodes are the core nodes in the photovoltaic area with serious self-voltage over-limit, strong influence on surrounding nodes, and little interference from the external environment. By adjusting such nodes, the problem of global voltage over-limit in the distribution network can be efficiently solved, and the grid stability can be improved.

[0061] Exemplarily, the determination of the critical load nodes in the voltage over-limit nodes based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic area can be achieved as follows: Based on the light intensity of the photovoltaic area and the photovoltaic proportion, the environmental influence factor of the voltage over-limit node is determined; based on the neighborhood influence factor, the environmental influence factor, and the influence coefficient of the voltage over-limit node, the critical load index of the voltage over-limit node is determined, and the voltage over-limit nodes with the critical load index greater than the third preset threshold are determined as the critical load nodes.

[0062] When the high-proportion photovoltaic area collaborative control method for the DCDC converter provided by the embodiment of the present application determines the above critical load nodes, the influence of the light intensity and the photovoltaic proportion in the distribution network is also considered. Specifically, the determination of the environmental influence factor of the voltage over-limit node based on the light intensity of the photovoltaic area and the photovoltaic proportion can be achieved as follows: Obtain the photovoltaic proportion of the distribution network of the photovoltaic area and the real-time light intensity of the photovoltaic area at each moment; based on the real-time light intensity and the photovoltaic proportion, the environmental influence factor at the corresponding moment is determined. Taking the t-th moment as an example, the above environmental influence factor can be specifically calculated by the following formula: , where, is the environmental influence factor at the t-th moment; is the real-time light intensity of the photovoltaic area at the t-th moment; is the photovoltaic proportion of the distribution network of the photovoltaic area; is the normalization function, The closer the value of is to 1, the more significant the influence of the environmental factor on the voltage; The closer the value of is to 0, the weaker the influence of the environmental factor on the voltage.

[0063] After determining the neighborhood influence factor and the environmental influence factor through the above process, further, the embodiment of the present application can correct the influence coefficient of the above voltage over-limit node on other nodes in the voltage over-limit area based on the neighborhood influence factor and the environmental influence factor to obtain the final critical load index. Exemplarily, determining the critical load index of the voltage over-limit node based on the neighborhood influence factor, the environmental influence factor, and the influence coefficient of the voltage over-limit node can be achieved as follows: Calculate the product of the reciprocal of the neighborhood influence factor and the environmental influence factor, denoted as the load correction coefficient; Calculate the product of the load correction coefficient, the influence coefficient of the voltage over-limit node, and the degree of voltage over-limit of the voltage over-limit node, denoted as the critical load index of the voltage over-limit node.

[0064] Specifically, taking the current voltage over-limit node as the k-th node in the voltage over-limit area as an example, the load correction coefficient of the k-th node at the t-th moment can be specifically calculated through the following formula: , where, is the load correction coefficient of the k-th node at the t-th moment; is the neighborhood influence factor of the k-th node at the t-th moment; is the environmental influence factor at the t-th moment; is the normalization function.

[0065] After calculating the load correction coefficient of the k-th node at the t-th moment through the above formula , further, the critical load index of the k-th node at the t-th moment can be determined through the following formula: , where, is the critical load index of the k-th node at the t-th moment; is the influence coefficient of the k-th node on other nodes in the voltage over-limit area; is the degree of voltage over-limit of the k-th node at the t-th moment; is the normalization function.

[0066] In the embodiment of the present application, after determining the critical load index of each voltage over-limit node in the above voltage over-limit area, taking the above third preset threshold as 0.6 as an example, determining the voltage over-limit node with the critical load index greater than the third preset threshold as the critical load node can be achieved as follows: Obtain the critical load index of each voltage over-limit node in the voltage over-limit area, and screen out the voltage over-limit nodes with the critical load index > 0.6, denoted as the critical load nodes.

[0067] In the embodiment of the present application, by performing reactive power compensation on the above-mentioned key load nodes, the voltages of each voltage over-limit node are adjusted to the normal range. Exemplarily, the reactive power compensation for the key load nodes can be achieved as follows: determining the sensitivity coefficients of each photovoltaic node in the photovoltaic area with respect to the key load nodes; wherein the sensitivity coefficient is used to characterize the influence degree of the unit reactive power change of the photovoltaic node on the voltage of the key load node; sorting the photovoltaic nodes based on the sensitivity coefficients, and determining the target compensation device in the photovoltaic inverters corresponding to the photovoltaic nodes based on the sorting result; calculating the reactive power compensation amount required by the key load node through the intelligent distribution transformer terminal, and generating a corresponding control instruction; sending the control instruction to the target compensation device to achieve reactive power compensation for the key load node through the target compensation device.

[0068] Specifically, the sensitivity coefficient of the above-mentioned photovoltaic node with respect to the key load node can be determined by power flow calculation or historical data fitting; after determining the sensitivity coefficients of each photovoltaic node, sorting the sensitivity coefficients in descending order, and determining the photovoltaic inverters corresponding to the top 30% of the sorted photovoltaic nodes as candidate compensation devices; obtaining the reactive power remaining capacity of each candidate compensation device, and taking the candidate compensation device with the largest reactive power remaining capacity as the target compensation device; calculating the reactive power compensation amount required for this reactive power compensation through the above-mentioned intelligent distribution transformer terminal system, and generating a corresponding control instruction; sending the generated control instruction to the target compensation device to perform reactive power compensation on the key load node through the target compensation device, so that the voltages of each voltage over-limit node in the voltage over-limit area return to normal.

[0069] After the embodiment of the present application performs reactive power compensation on the key load node through the above process, it is also necessary to judge the compensation result. Exemplarily, the judgment process can be achieved as follows: after performing reactive power compensation on the key load node, obtaining the real-time voltages of each node in the photovoltaic area, and judging whether there are voltage over-limit nodes in the photovoltaic area based on the real-time voltages; if there are voltage over-limit nodes, determining the target compensation device for the voltage over-limit nodes, and performing reactive power compensation on the voltage over-limit nodes based on the target compensation device until there are no voltage over-limit nodes in the photovoltaic area. That is, if there are still voltage over-limit nodes in the photovoltaic area after adjustment, return to the above step of performing reactive power compensation until there are no voltage over-limit nodes in the photovoltaic area.

[0070] Preferably, the embodiments of the present application can also construct a reactive voltage electrical distance matrix between different photovoltaic regions, and determine an optimal reactive power scheduling strategy based on the reactive voltage electrical distance matrix to coordinate the voltage regulation between different regions, and finally ensure that the voltage of the entire distribution network remains within a safe range. For example, if the electrical distance between photovoltaic region A and photovoltaic region B is less than 0.5, it proves that the voltage fluctuations between these two photovoltaic regions are strongly correlated and need to be coordinated for scheduling; at this time, if photovoltaic region A is overvoltage, even if the voltage of photovoltaic region B does not exceed the limit, the reactive power output needs to be adjusted synchronously.

[0071] The above mainly introduces the solution provided by the embodiments of the present invention from the perspective of methods. To implement the above functions, it includes the corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should easily realize that, combining the units and algorithm steps of each example described in the embodiments disclosed herein, the present invention can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0072] Correspondingly, the embodiments of the present disclosure also provide a high-proportion photovoltaic region collaborative control device for a DCDC converter. Refer to Figure 2 As shown, the high-proportion photovoltaic region collaborative control device 200 for a DCDC converter may include a data acquisition module 210, a data processing module 220, and a voltage regulation module 230, where: The data acquisition module 210 is configured to acquire the node operation data of each node in the photovoltaic region; the above nodes are DCDC converters deployed in the photovoltaic region, and the node operation data includes the real-time voltage; The data processing module 220 is configured to determine the voltage over-limit nodes among the above nodes based on the real-time voltage, and construct a voltage over-limit region based on the voltage over-limit nodes; The data processing module 220 is further configured to, for each voltage over-limit node in the voltage over-limit region, determine the influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit region based on the position information and real-time voltage of the voltage over-limit node; The data processing module 220 is further configured to determine the neighborhood nodes connected to the voltage over-limit nodes in the voltage over-limit region, and calculate the average value of the influence coefficients of each neighborhood node, which is denoted as the neighborhood influence factor of the voltage over-limit node; The data processing module 220 is further configured to determine the critical load nodes among the voltage over-limit nodes based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic region; A voltage regulation module 230 is configured to perform reactive power compensation on critical load nodes to regulate the voltage of voltage over-limit nodes.

[0073] The specific implementation details of the above high-proportion photovoltaic substation area collaborative control device for DCDC converters have been described in detail at the corresponding positions of the high-proportion photovoltaic substation area collaborative control method for DCDC converters, so they will not be elaborated here.

[0074] The above description is only a preferred embodiment of the present disclosure and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosure concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present disclosure.

[0075] In addition, although the operations are depicted in a particular order, this should not be construed as requiring that the operations be performed in the particular order shown or in sequential order. In certain environments, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the present disclosure. Certain features described in the context of separate embodiments may also be implemented combinatorially in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments.

Claims

1. A high-proportion photovoltaic substation collaborative control method for a DCDC converter, characterized in that, The method includes: Collecting node operation data of each node in the photovoltaic substation area; the node is a DCDC converter deployed in the photovoltaic substation area, and the node operation data includes real-time voltage; Determining voltage over-limit nodes in the nodes based on the real-time voltage, and constructing a voltage over-limit area based on the voltage over-limit nodes; For each voltage over-limit node in the voltage over-limit area, determining the influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit area based on the position information of the voltage over-limit node and the real-time voltage; Determining neighborhood nodes connected to the voltage over-limit node in the voltage over-limit area, and calculating the average value of the influence coefficients of each neighborhood node, which is denoted as the neighborhood influence factor of the voltage over-limit node; Determining key load nodes in the voltage over-limit nodes based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic substation area, and performing reactive power compensation on the key load nodes to adjust the voltage of the voltage over-limit nodes.

2. The high-proportion photovoltaic substation collaborative control method for DCDC converters according to claim 1, wherein The determining voltage over-limit nodes in the nodes based on the real-time voltage, and constructing a voltage over-limit area based on the voltage over-limit nodes includes: Obtaining the rated voltage of each power device on the node, and determining the normal voltage of the node based on the rated voltage; Obtaining the real-time voltage of the node collected at the current moment, and calculating the difference between the real-time voltage at the current moment and the normal voltage of the node, which is denoted as the voltage over-limit degree of the node; Determining the node with the voltage over-limit degree greater than the first preset threshold as the abnormal node at the current moment; For each abnormal node at the current moment, obtaining the real-time voltage of the abnormal node collected at historical moments, and determining the abnormal frequency of the abnormal node being marked as abnormal at the historical moments based on the real-time voltages at the historical moments and the normal voltage of the abnormal node; Determining the abnormal node at the current moment with the abnormal frequency greater than the second preset threshold as the voltage over-limit node; Constructing the voltage over-limit area according to the distribution of each voltage over-limit node in the photovoltaic substation area.

3. The high-proportion photovoltaic substation collaborative control method for a DCDC converter according to claim 2, characterized in that The determining the influence coefficient of the voltage over-limit node on other nodes in the voltage over-limit area based on the position information of the voltage over-limit node and the real-time voltage for each voltage over-limit node in the voltage over-limit area includes: Determining the current voltage over-limit node in the voltage over-limit area, and determining the distance level of other nodes according to the topological distance between the current voltage over-limit node and other nodes in the distribution topology network of the photovoltaic substation area; At each distance level, determining the distance correlation of the current voltage over-limit node at the distance level based on the physical distance between the current voltage over-limit node and each other node at the distance level; Determine a first voltage change amplitude sequence corresponding to the current voltage over-limit node based on the difference in the real-time voltage of the current voltage over-limit node at the adjacent historical moments; At each of the distance levels, determine a second voltage change amplitude sequence corresponding to the other nodes based on the difference in the real-time voltage of the other nodes at the adjacent historical moments, and determine the voltage correlation of the current voltage over-limit node at the distance level based on the first voltage change amplitude sequence and the second voltage change amplitude sequence; Determine the influence coefficient corresponding to the current voltage over-limit node according to the distance correlation and the voltage correlation between the current voltage over-limit node and the other nodes at each of the distance levels; 4. The high-proportion photovoltaic substation collaborative control method for a DCDC converter according to claim 3, wherein The determining the distance correlation of the current voltage over-limit node at the distance level based on the physical distance between the current voltage over-limit node and each of the other nodes at the distance level includes: For each of the other nodes at the distance level, calculate the Euclidean distance between the other node and the current voltage over-limit node, and determine the node distance correlation between the current voltage over-limit node and the other node based on the Euclidean distance and the topological distance corresponding to the distance level; Calculate the average value of the node distance correlations at the distance level, and denote it as the distance correlation of the current voltage over-limit node at the distance level; 5. The high-proportion photovoltaic substation area collaborative control method for a DCDC converter according to claim 3, characterized in that The determining the voltage correlation of the current voltage over-limit node at the distance level based on the first voltage change amplitude sequence and the second voltage change amplitude sequence includes: Calculate the Pearson correlation coefficient between the first voltage change amplitude sequence and each of the second voltage change amplitude sequences; Calculate the average value of the Pearson correlation coefficients at the distance level, and denote it as the voltage correlation of the current voltage over-limit node at the distance level; 6. The high-proportion photovoltaic substation area collaborative control method for a DCDC converter according to claim 3, characterized in that, The determining the influence coefficient corresponding to the current voltage over-limit node according to the distance correlation and the voltage correlation between the current voltage over-limit node and the other nodes at each of the distance levels includes: Calculate the average value of the product of the distance correlation and the voltage correlation at each of the distance levels, and denote it as the initial influence coefficient corresponding to the current voltage over-limit node; Determine the regional voltage over-limit degree of the voltage over-limit region based on the voltage over-limit degree of each voltage over-limit node in the voltage over-limit region; Determine the influence coefficient corresponding to the current voltage over-limit node based on the voltage over-limit degree of the current voltage over-limit node, the regional voltage over-limit degree, and the initial influence coefficient; 7. The high-ratio photovoltaic substation collaborative control method for a DCDC converter according to claim 2, wherein The determining the critical load nodes among the voltage over-limit nodes based on the neighborhood influence factor of the voltage over-limit node, the influence coefficient of the voltage over-limit node, and the light intensity of the photovoltaic substation area includes: Determine the environmental influence factor of the voltage over-limit node based on the light intensity and the photovoltaic proportion of the photovoltaic substation area; Based on the neighborhood influence factor, the environmental influence factor, and the influence coefficient of the voltage over-limit node, determine the critical load index of the voltage over-limit node, and determine the voltage over-limit node with the critical load index greater than the third preset threshold as the critical load node.

8. The high-proportion photovoltaic substation collaborative control method for a DCDC converter according to claim 7, characterized in that, The determining the critical load index of the voltage over-limit node based on the neighborhood influence factor, the environmental influence factor, and the influence coefficient of the voltage over-limit node includes: Calculate the product of the reciprocal of the neighborhood influence factor and the environmental influence factor, and denote it as the load correction coefficient; Calculate the product of the load correction coefficient, the influence coefficient of the voltage over-limit node, and the voltage over-limit degree of the voltage over-limit node, and denote it as the critical load index of the voltage over-limit node.

9. The high-ratio photovoltaic substation collaborative control method for a DCDC converter according to claim 1, wherein The performing reactive power compensation on the critical load node includes: Determine the sensitivity coefficient of each photovoltaic node in the photovoltaic substation area with respect to the critical load node; wherein, the sensitivity coefficient is used to characterize the influence degree of the change in the unit reactive power of the photovoltaic node on the voltage of the critical load node; Sort the photovoltaic nodes based on the sensitivity coefficient, and determine the target compensation device in the photovoltaic inverters corresponding to the photovoltaic nodes based on the sorting result; Calculate the reactive power compensation amount required by the critical load node through the intelligent distribution transformer terminal, and generate a corresponding control command; Send the control command to the target compensation device to achieve reactive power compensation for the critical load node through the target compensation device.

10. The high-ratio photovoltaic substation collaborative control method for a DCDC converter according to claim 9, characterized in that, The performing reactive power compensation on the critical load node further includes: After performing reactive power compensation on the critical load node, obtain the real-time voltage of each node in the photovoltaic substation area, and determine whether there is a voltage over-limit node in the photovoltaic substation area based on the real-time voltage; If there is a voltage over-limit node, determine the target compensation device for the voltage over-limit node, and perform reactive power compensation on the voltage over-limit node based on the target compensation device until there is no voltage over-limit node in the photovoltaic substation area.

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