Distribution network closed-loop steady-state current and impulse current analysis and calculation system

Abstract

The invention provides a distribution network closed-loop steady-state current and impact current analysis and calculation system, and relates to the technical field of distribution network operation protection. The system comprises a data acquisition module, a modeling analysis module, a steady-state current analysis module, an impact current analysis module and a safety early warning module. Acquiring operation data of the power distribution network in real time; acquiring connected components of the power distribution network; identifying position information of a loop closing point; calculating the current steady-state current and predicting the steady-state current at the next moment; analyzing the change trend of the impact current; and setting safety thresholds of the steady-state current and the impulse current. Through the synergistic effect of all the modules, comprehensive and accurate analysis and effective management and control of the distribution network closed-loop steady-state current and the impulse current are realized. The operation quality and reliability of the power distribution network are remarkably improved, the maintenance cost and potential risks are reduced, and new vitality is injected to sustainable development of the power industry.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network operation protection, and particularly to an analysis and calculation system for steady-state current and impact current of distribution network loop closing. Background Art

[0002] The steady-state current of distribution network loop closing refers to the current flowing through the system when the distribution network loop closing operation is completed and the system reaches a stable operation state. It reflects the current distribution of the distribution network under normal working conditions after loop closing. The impact current of distribution network loop closing is a short-term and large-amplitude current generated instantaneously during the distribution network loop closing operation. This kind of current usually has the characteristics of a high amplitude and rapid change.

[0003] In the distribution network system, the structure of the distribution network is complex and changeable, and it is impossible to clearly understand the flow path and distribution law of electric power in the network. It is impossible to accurately grasp the real-time situation and future trend of the current, resulting in the inability to plan and adjust the operation strategy of the distribution network in advance, increasing the risk of equipment damage and power supply failures. The operation of the distribution network is often in a relatively blind state. Without being able to make reasonable plans and adjustments in advance, it may lead to excessive loads on equipment during peak electricity consumption or special situations, increasing the risk of equipment damage. The damage of equipment will not only increase the maintenance cost, but also may cause local or even large-scale power supply failures, bringing great inconvenience and losses to production and life. Summary of the Invention

[0004] The present invention provides an analysis and calculation system for steady-state current and impact current of distribution network loop closing to solve the defects existing in the prior art.

[0005] The present invention provides an analysis and calculation system for steady-state current and impact current of distribution network loop closing, including: A data acquisition module, which is used to collect the operation data of the distribution network in real time and preprocess the operation data to obtain preprocessed data.

[0006] A modeling and analysis module, which is used to construct a geometric model based on the finite element analysis method, implement the depth-first search algorithm to obtain the connected components of the distribution network, and use the minimum spanning tree algorithm to identify the position information of the loop closing point.

[0007] A steady-state current analysis module, which is used to perform power flow analysis on the geometric model according to the Newton-Raphson method and power flow calculation iteration technology to obtain the current steady-state current, and construct a prediction model based on the support vector machine, input the preprocessed data, connected components, position information of the loop closing point and the current steady-state current, and output the predicted steady-state current.

[0008] An impact current analysis module, which is used to construct a circuit simulation model, obtain the behavior characteristics of the impact current, and analyze the change trend of the impact current by using the finite difference method.

[0009] A safety warning module is used to set safety thresholds for steady-state current and surge current. When the current steady-state current, predicted steady-state current value, or surge current exceeds the set threshold, it triggers the alarm system.

[0010] According to a system for analyzing and calculating steady-state current and surge current in a distribution network loop provided by the present invention, the data acquisition module includes a real-time monitoring unit. The real-time monitoring unit is used to collect the operation data of the distribution network in real time through data acquisition devices. The operation data includes voltage data, current data, power data, and frequency data.

[0011] According to a system for analyzing and calculating steady-state current and surge current in a distribution network loop provided by the present invention, the data acquisition module further includes a data preprocessing unit. The data preprocessing unit is used to preprocess the collected operation data. The process includes: Using the Kalman filter algorithm to remove random noise in the operation data, and using the Z-score method to identify and remove outliers in the operation data.

[0012] Using the moving average method to smooth the operation data, and using data normalization to convert the operation data to a unified range.

[0013] Using the interpolation method to process the missing values in the operation data to obtain a complete data set, and taking the complete data set as the preprocessed data.

[0014] According to a system for analyzing and calculating steady-state current and surge current in a distribution network loop provided by the present invention, the process of constructing a geometric model based on the finite element analysis method includes: Setting physical properties and electrical behaviors. The physical properties include current distribution and temperature field, and the electrical behaviors include steady-state current and local voltage changes.

[0015] Collecting the design parameters of the distribution network. The design parameters include basic component specifications. Combining the preprocessed data, using the finite element analysis method to construct a geometric model of the distribution network, and drawing basic components in the geometric model. The basic components include connecting lines, switches, transformers, and loads.

[0016] Assigning preset material properties to each component in the geometric model. The material properties include conductivity, permittivity, and thermal conductivity, and inputting the material properties into the geometric model.

[0017] Selecting the quadrilateral element type and dividing the geometric model into finite element meshes.

[0018] Setting boundary conditions. The boundary conditions include fixed ends, symmetry planes, voltage sources, and current sources, and applying external loads to simulate the operation state of the distribution network. The external loads include current input and heat sources.

[0019] Adopt a dynamic analysis and solution algorithm, configure the solution parameters, and obtain the current distribution data and voltage distribution data of the geometric model. The solution parameters include the convergence criterion and the time step.

[0020] According to a system for analyzing and calculating the steady-state current and inrush current of a distribution network loop provided by the present invention, the process of implementing a depth-first search algorithm to obtain the connected components of the distribution network includes: Regard transformers, loads, and switches as nodes in the distribution network topology data, and regard the connecting lines as edges in the distribution network topology data.

[0021] Convert the distribution network into a graph model, where nodes represent electrical equipment and edges represent electrical connections, and use an adjacency matrix to represent the structure of the graph model.

[0022] Create an empty set, define a depth-first search function, take the current node, the structure of the graph, and the set of visited nodes as parameters of the depth-first search function, add the current node to the empty set, and mark it as visited. Traverse all adjacent nodes of the current node, and for each unvisited adjacent node, recursively call the depth-first search function.

[0023] If the adjacent node of the node has been visited, it means there is a connection path. Traverse all nodes in the graph model to obtain all connected components.

[0024] According to a system for analyzing and calculating the steady-state current and inrush current of a distribution network loop provided by the present invention, the process of using a minimum spanning tree algorithm to identify the position information of the loop closing point includes: Create an empty minimum spanning tree set, use a priority queue to store edges and sort them according to weights. The weights include resistance and distance. Take one end node of the edge with the smallest weight as the starting node, add the starting node to the minimum spanning tree set and mark it as having been added to the minimum spanning tree.

[0025] Add the edge with the smallest weight and its second node that is not in the tree to the minimum spanning tree, mark the second node as having been added to the minimum spanning tree set, and add all edges connected to the second node to the priority queue.

[0026] Take the second node after adding it to the minimum spanning tree set as the new starting node, add the new edge connected to the new starting node and the next node connected by the new edge to the minimum spanning tree, mark the next node as having been added to the minimum spanning tree set, and add all edges connected to the next node to the priority queue.

[0027] Until all nodes are added to the minimum spanning tree, the node that forms a loop connection with the already connected node when the node connected to the existing tree is added to the minimum spanning tree set is used as the loop closing point.

[0028] According to a system for analyzing and calculating the steady-state current and impact current of a distribution network loop closing provided by the present invention, the process of performing power flow analysis on a geometric model according to the Newton-Raphson method and power flow calculation iteration technology includes: Obtain the initial voltage value and initial current value of the geometric model, and set the convergence conditions, where the convergence conditions include the voltage change tolerance.

[0029] Construct a Jacobian matrix according to the topological structure data of the distribution network combined with the preprocessing data, and use the voltage data at the loop closing point and the partial derivatives of the power equation at the loop closing point as the elements of the Jacobian matrix.

[0030] Convert the power flow calculation into a system of nonlinear equations, where the system of nonlinear equations includes the power balance equation at the loop closing point.

[0031] Use the Newton-Raphson iteration formula to update the voltage at the loop closing point, and check whether the change in the voltage at the loop closing point meets the set convergence conditions. If the conditions are met, it is determined that convergence has occurred.

[0032] Obtain the current steady-state current according to the voltage value at the loop closing point and the power balance equation at the loop closing point.

[0033] According to a system for analyzing and calculating the steady-state current and impact current of a distribution network loop closing provided by the present invention, the process of constructing a prediction model based on a support vector machine includes: Collect the historical operation data of each node in the distribution network, and obtain the historical connected components, historical loop closing point location information, and historical steady-state current of the distribution network according to the historical operation data, and label the steady-state current at the next moment corresponding to the historical steady-state current.

[0034] Construct a basic support vector machine model using a polynomial kernel function. Use the historical operation data, historical connected components, historical loop closing point location information, and historical steady-state current as inputs, and the steady-state current at the next moment as the output. Train the basic model, retain the model parameters that meet the accuracy rate, and obtain the prediction model.

[0035] According to a loop closing steady-state current and impact current analysis and calculation system provided by the present invention, the impact current analysis module includes a circuit simulation model unit and a change trend acquisition unit. The circuit simulation model unit is used to construct a circuit simulation model using a preset circuit simulation tool to simulate the behavioral characteristics of the impact current in the distribution network, and the behavioral characteristics include current waveform, current peak value, and current frequency. The change trend acquisition unit is used to establish a time-domain differential equation describing the impact current according to the physical characteristics of the distribution network, and the physical characteristics include inductance, capacitance, and resistance. Perform Laplace transform on the time-domain differential equation to convert the time-domain differential equation into a frequency-domain equation. Express the Laplace transform relationship between the input voltage and the output current as a transfer function. Through inverse Laplace transform, convert the transfer function of the frequency-domain equation into a time-domain equation to obtain the time-domain response of the impact current. Discretize the time-domain response in time, define a discrete time step, and generate a discrete time series. According to the discretization, use the finite difference method to convert the time-domain equation into a discrete form. Solve the current values in the discrete time series and analyze the change trend of the impact current over time.

[0036] According to a loop closing steady-state current and impact current analysis and calculation system provided by the present invention, the safety threshold includes the maximum allowable steady-state current value and the maximum allowable impact current behavioral characteristic value.

[0037] A system for analyzing and calculating the steady-state current and impact current of a distribution network loop provided by the present invention preprocesses the operation data of the distribution network collected in real time, ensuring the accuracy and effectiveness of the data. This enables subsequent analysis to be based on high-quality data, accurately reflecting the actual operation status of the distribution network, improving the timeliness and comprehensiveness of monitoring the operation status of the distribution network, and providing the possibility for quickly locating and solving problems. An advanced algorithm is used to construct a geometric model and obtain key information, providing a basis for deeply understanding the structure and operation characteristics of the distribution network. Accurately mastering the connected components and loop connection points of the distribution network helps to optimize the grid layout, improve power transmission efficiency, reduce energy loss, and lower operating costs. By using an advanced method for power flow analysis and prediction, the current steady-state current situation can be accurately grasped, and the future steady-state current can be reliably predicted. This provides a scientific basis for the planning and scheduling of the distribution network, enabling the operating strategy to be adjusted in advance to avoid problems such as equipment overload and aging caused by abnormal steady-state current, extending the service life of equipment, and reducing maintenance and replacement costs. By constructing a simulation model and applying a professional method to analyze the transient process and change trend, the characteristics of the impact current can be deeply understood. Thus, targeted protection measures can be taken to reduce the risk of damage to equipment caused by the impact current, enhancing the anti-interference ability and stability of the distribution network. By setting a safety threshold and triggering an alarm when the current is abnormal, the operation and maintenance personnel can be reminded in a timely manner. Ensuring that measures are taken promptly when the current exceeds the safe range to avoid the expansion of accidents and guarantee the safety of personnel and equipment. Reducing the power outage time and scope, improving power supply reliability, enhancing user satisfaction, and providing strong support for the stable development of the social economy. Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a schematic structural diagram of a system for analyzing and calculating the steady-state current and impact current of a distribution network loop provided by an embodiment of the present invention; Figure 2 It is a unit structure diagram of the impact current analysis module in an embodiment of the present invention; Figure 3 It is a flowchart of the change trend acquisition unit in an embodiment of the present invention. Detailed Embodiments

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts fall within the scope of protection of the present invention.

[0041] The following will describe Figures 1 - 3 a system for analyzing and calculating the steady-state current and inrush current of a distribution network loop closure in the present invention.

[0042] Figure 1 is a schematic structural diagram of a system for analyzing and calculating the steady-state current and inrush current of a distribution network loop closure provided by an embodiment of the present invention.

[0043] As Figure 1 shown, a system for analyzing and calculating the steady-state current and inrush current of a distribution network loop closure provided by an embodiment of the present invention includes a data acquisition module, a modeling and analysis module, a steady-state current analysis module, an inrush current analysis module, and a safety warning module.

[0044] The data acquisition module is used to collect the operation data of the distribution network in real time and preprocess the operation data to obtain preprocessed data.

[0045] The data acquisition module includes a real-time monitoring unit. The real-time monitoring unit is used to collect the operation data of the distribution network in real time through data acquisition devices. The operation data includes voltage data, current data, power data, and frequency data.

[0046] The data acquisition module further includes a data preprocessing unit. The data preprocessing unit is used to preprocess the collected operation data. The process includes: Using the Kalman filter algorithm to remove the random noise in the operation data and using the Z-score method to identify and remove the outliers in the operation data. The Kalman filter algorithm filters the collected operation data through a dynamic model to remove the random noise, effectively improving the signal-to-noise ratio and accuracy of the data. Calculate the Z-score of each data point, and identify and remove the outliers by setting a threshold to ensure the normality and consistency of the data.

[0047] Using the moving average method to smooth the operation data and using data normalization to convert the operation data to a unified range. Applying the moving average algorithm to the operation data reduces the interference of data fluctuations on the analysis results and extracts the basic trend of the data. The normalization process converts the preprocessed data to a unified range to avoid the influence of different dimensions or units on subsequent calculations and ensure the comparability of each data dimension.

[0048] The interpolation method is used to process the missing values in the operation data to obtain a complete data set, and the complete data set is used as the preprocessed data.

[0049] In this embodiment, sensors, data acquisition cards, and special measuring instruments are connected to the distribution network to dynamically obtain real-time data. The collected data is transmitted to the data processing center using a standard communication protocol to ensure the accuracy and real-time nature of data transmission. The real-time monitoring unit obtains the operation data of each node in the distribution network by connecting various data acquisition devices, including: Voltage data records the voltage conditions of each node in the real-time recording system. Current data monitors the current changes of each node. Power data calculates and records the power values of each node. Frequency data monitors the electrical frequency of the system to ensure it is within the allowable range.

[0050] The modeling and analysis module is used to construct a geometric model based on the finite element analysis method, and implement a depth-first search algorithm to obtain the connected components of the distribution network, and use the minimum spanning tree algorithm to identify the location information of the loop closing points.

[0051] The process of constructing a geometric model based on the finite element analysis method includes: Set physical properties and electrical behaviors. Physical properties include current distribution and temperature field. The current distribution defines the flow path and distribution of current in the distribution network, taking into account the connection methods of different components and their influence on current flow. The temperature field sets a temperature distribution model to analyze the thermal effects generated when current passes through each component, ensuring that the temperature does not exceed the safety threshold.

[0052] Electrical behaviors include steady-state current and local voltage changes. Set the initial conditions of the steady-state current in the model to ensure that the model can reflect the actual operating state. Local voltage changes consider the voltage changes of each node in the distribution network under different load conditions, especially the voltage fluctuations near the loop closing points.

[0053] Collect the design parameters of the distribution network. The design parameters include the specifications of basic components. Combining the preprocessed data, use the finite element analysis method to construct a geometric model of the distribution network. Draw basic components in the geometric model. The basic components include connection lines, switches, transformers, and loads. The connection lines represent the wires for current transmission and need to be drawn according to the actual specifications. The switches are used to control the flow of current and identify their switch states. Draw the position and connection method of the transformer to ensure that its interaction with other components is accurately represented. Set the type and position of the load according to the power demand of the load.

[0054] Assign preset material properties to each component in the geometric model. The material properties include conductivity, permittivity, and thermal conductivity, and input the material properties into the geometric model. Set the conductivity for wires and other conductive components to accurately simulate current flow. Set the permittivity for insulating materials to analyze the electric field distribution. Set the thermal conductivity for all components to simulate the temperature field and heat transfer conduction. Input the material properties into the finite element analysis software to ensure that the model accurately reflects the actual physical characteristics.

[0055] Select the quadrilateral element type and divide the geometric model into a finite element mesh. According to the complexity of the geometric model and the requirements of computational accuracy, select quadrilateral elements and divide the geometric model into a finite element mesh to ensure that the fineness of the mesh can capture the changes in current and temperature fields. Finer meshes can be used near the closed-loop points and transformers to improve the computational accuracy.

[0056] Set the boundary conditions. The boundary conditions include fixed ends, symmetry planes, voltage sources, and current sources. Set the boundary conditions for the components with fixed connections at the fixed ends to ensure that they do not displace during the calculation process. In the case of symmetric structures, set the symmetric boundary conditions to reduce the computational amount. Specify the positions and input values of the voltage sources and current sources in the model to simulate the actual operating state.

[0057] And apply external loads to simulate the operating state of the distribution network. The external loads include current input and heat sources. Ensure that the model can reflect the actual working conditions.

[0058] Adopt a dynamic analysis solution algorithm, configure the solution parameters, and obtain the current distribution data and voltage distribution data of the geometric model. The solution parameters include the convergence criterion and the time step. Set the convergence criterion during the solution process to ensure the accuracy of the numerical solution. According to the dynamic characteristics of the model, set an appropriate time step to capture the current and temperature changes during the transient process.

[0059] Run the finite element analysis solver to obtain the current distribution data and voltage distribution data of the geometric model. Monitor the convergence situation during the solution process and make adjustments to possible numerical instabilities.

[0060] The geometric model constructed based on the finite element analysis method can accurately reflect the electrical behavior and physical characteristics of the distribution network. Ensure that subsequent steady-state current analysis and surge current analysis can be carried out based on accurate data, thereby providing reliable calculation results and warning information.

[0061] The process of implementing the depth-first search algorithm to obtain the connected components of the distribution network includes: Take transformers, loads, and switches as nodes in the distribution network topology data, and take the connecting lines as edges in the distribution network topology data.

[0062] Convert the distribution network into a graph model, where nodes represent electrical devices, edges represent electrical connections, and the adjacency matrix is used to represent the structure of the graph model.

[0063] Create an empty set, define a depth-first search function, take the current node, the structure of the graph, and the set of visited nodes as parameters of the depth-first search function, add the current node to the empty set and mark it as visited, traverse all adjacent nodes of the current node, and for each unvisited adjacent node, recursively call the depth-first search function.

[0064] If the adjacent node of a node has been visited, it means there is a connection path. Traverse all nodes in the graph model to obtain all connected components.

[0065] By treating electrical devices such as transformers, loads, and switches as nodes in the network and the connecting wires as edges, the structure of the distribution network is transformed into a graph model, which helps to intuitively understand the electrical connections of the distribution network. It simplifies the complexity of the distribution network and makes the subsequent algorithm implementation more intuitive and efficient. The depth-first search algorithm can efficiently identify the connected components in the distribution network, ensuring that each node and edge are accurately traversed, which is crucial for subsequent steady-state current and impulse current analysis. During the process of obtaining the connected components, ensure that the connection relationships between each electrical device are fully explored to achieve more accurate network analysis. Due to the recursive nature of the depth-first search algorithm, the algorithm can quickly locate the connection paths between electrical devices, improving the speed and efficiency of the analysis.

[0066] The process of using the minimum spanning tree algorithm to identify the location information of loop closing points includes: Create an empty minimum spanning tree set, use a priority queue to store edges and sort them according to weights, where the weights include resistance and distance. Take one end node of the edge with the smallest weight as the starting node, add the starting node to the minimum spanning tree set and mark it as having been added to the minimum spanning tree.

[0067] Add the edge with the smallest weight and its second node that is not in the tree to the minimum spanning tree, and mark the second node as having been added to the minimum spanning tree set. Add all the edges connected to the second node to the priority queue.

[0068] Take the second node after adding it to the minimum spanning tree set as the new starting node, add the new edge connected to the new starting node and the next node connected by the new edge to the minimum spanning tree, and mark the next node as having been added to the minimum spanning tree set. Add all the edges connected to the next node to the priority queue.

[0069] Until all nodes are added to the minimum spanning tree, the node that forms a loop connection with the already connected node when the node connected to the existing tree is added to the minimum spanning tree set is the loop closing point.

[0070] By creating a set of empty minimum spanning trees and combining a priority queue to store edges and sort them by weight, it can be ensured that the algorithm selects the edge with the lowest connection cost for processing in each iteration. This effectively reduces the energy loss in current distribution and improves the efficiency of data processing. Gradually adding the edge with the minimum weight and its nodes to the minimum spanning tree set can systematically establish the topological structure of the distribution network and accurately reflect the connection relationship between nodes. This lays a solid foundation for further current analysis and makes the subsequent calculation of steady-state current and surge current more accurate. During the process of adding to the minimum spanning tree, by dynamically updating the priority queue, it is ensured that the next edge to be processed is always the optimal choice for connecting new nodes, thus maximizing the operating efficiency of the algorithm. After all nodes are added, accurately identifying the loop closing points is crucial for the reasonable layout and optimal scheduling of the power grid.

[0071] The steady-state current analysis module is used to perform power flow analysis on the geometric model according to the Newton-Raphson method and power flow calculation iteration technology to obtain the current steady-state current, and construct a prediction model based on support vector machines. Input the preprocessed data, connected components, location information of loop closing points, and the current steady-state current, and output the predicted steady-state current.

[0072] According to the Newton-Raphson method and power flow calculation iteration technology, the process of performing power flow analysis on the geometric model includes: Obtain the initial voltage value and initial current value of the geometric model, and set the convergence conditions, which include the voltage change tolerance. Appropriate initial voltage and current values can be initialized according to the historical data or standard reference values of the distribution network. These initial values will serve as the starting point for power flow calculation. Define the convergence conditions to ensure that the iterative process can terminate within a reasonable range and avoid excessive calculation steps.

[0073] Construct the Jacobian matrix based on the topological structure data of the distribution network combined with the preprocessed data, and use the loop closing point voltage data and the partial derivatives of the loop closing point power equation as the elements of the Jacobian matrix. According to the topological structure data of the distribution network, extract the connection situation of each node, including components such as voltage sources, loads, and transformers. According to the power balance equation of each loop closing point, that is, the sum of the inflowing and outflowing powers is zero, construct the corresponding nonlinear equation to ensure the accuracy of the model.

[0074] Convert the power flow calculation into a system of nonlinear equations, and the system of nonlinear equations includes the loop closing point power balance equation.

[0075] Use the Newton-Raphson iteration formula to update the loop closing point voltage, and check whether the change in the loop closing point voltage meets the set convergence conditions. If the conditions are met, it is judged to have converged.

[0076] Obtain the current steady-state current according to the loop closing point voltage value and the loop closing point power balance equation.

[0077] The power flow analysis based on the Newton-Raphson method can effectively calculate the steady-state current of the distribution network accurately. Depending on the construction of the Jacobian matrix and the non-linear equations system, the system can not only reflect the current current state, but also provide a reliable data basis for subsequent system optimization, fault analysis and safety warning.

[0078] The process of constructing a prediction model based on the support vector machine includes: Collect the historical operation data of each node in the distribution network, and obtain the historical connected components, the historical loop closing point position information and the historical steady-state current of the distribution network according to the historical operation data, and label the steady-state current at the next moment corresponding to the historical steady-state current.

[0079] Construct a basic support vector machine model using the polynomial kernel function, take the historical operation data, historical connected components, historical loop closing point position information and historical steady-state current as inputs, and the steady-state current at the next moment as the output, train the basic model, retain the model parameters that meet the accuracy rate, and obtain the prediction model.

[0080] Figure 2 It is the unit structure diagram of the impact current analysis module in the embodiment of the present invention, as Figure 2 shown, the impact current analysis module is used to construct a circuit simulation model, apply the Laplace transform and transient analysis methods to model the transient process of the impact current, and use the finite difference method to analyze the change trend of the impact current.

[0081] The impact current analysis module includes a circuit simulation model unit and a change trend acquisition unit. The circuit simulation model unit is used to construct a circuit simulation model using a preset circuit simulation tool to simulate the behavioral characteristics of the impact current in the distribution network, and the behavioral characteristics include current waveform, current peak value and current frequency.

[0082] Figure 3 It is the flowchart of the change trend acquisition unit in the embodiment of the present invention, as Figure 3 shown, the change trend acquisition unit is used to establish a time-domain differential equation describing the impact current according to the physical characteristics of the distribution network, and the physical characteristics include inductance, capacitance and resistance. Perform the Laplace transform on the time-domain differential equation to convert the time-domain differential equation into a frequency-domain equation. Represent the Laplace transform relationship between the input voltage and the output current as a transfer function. Through the inverse Laplace transform, convert the transfer function of the frequency-domain equation into a time-domain equation to obtain the time-domain response of the impact current. Discretize the time-domain response in time, define the discrete time step, and generate a discrete time series. According to the discretization, use the finite difference method to convert the time-domain equation into a discrete form. Solve the current values in the discrete time series and analyze the change trend of the impact current over time.

[0083] The safety warning module is used to set the safety thresholds for the steady-state current and the surge current. When the current steady-state current, the predicted steady-state current value, or the surge current exceeds the set threshold, the alarm system is triggered. The safety thresholds include the maximum allowable steady-state current value and the maximum allowable surge current behavior characteristic value.

[0084] In this embodiment, based on various information such as the design specifications of the distribution network, the rated parameters of the equipment, and the historical operation data, the maximum allowable steady-state current value and the maximum allowable surge current behavior characteristic value are determined. During the operation of the system, the safety warning module will receive in real-time the current steady-state current, the predicted steady-state current value, and the surge current data provided by the steady-state current analysis module and the surge current analysis module. For the steady-state current, the module will compare the currently measured steady-state current value with the set maximum allowable steady-state current value. If the current steady-state current exceeds the threshold, the module will immediately trigger an alarm. At the same time, for the predicted steady-state current value, if the prediction shows that the steady-state current may exceed the threshold within a certain future time period, an early warning will also be issued in advance so that the staff can take timely measures to adjust the operation state of the distribution network. For the surge current, the safety warning module will compare the obtained surge current data with the maximum allowable surge current behavior characteristic value. The behavior characteristic values of the surge current include the current waveform, the current peak value, and the current frequency. As long as the surge current exceeds the set threshold in any one of the key parameters, the alarm system will be triggered. Once the alarm is triggered, the safety warning module will send alarm messages to relevant personnel in various ways, such as displaying prominent warning signs on the monitoring interface, sending email or text message notifications, triggering the audible and visual alarm device, etc. After receiving the alarm, the relevant personnel can quickly take measures, such as adjusting the load, switching the line, starting the standby power supply, etc., to ensure the safe and stable operation of the distribution network.

[0085] In summary, this embodiment provides an analysis and calculation system for steady-state current and impact current in network loop closing. By collecting and preprocessing the operation data of the distribution network in real time, the accuracy and effectiveness of the data are ensured. This enables subsequent analysis to be based on high-quality data, accurately reflecting the actual operation status of the distribution network, improving the timeliness and comprehensiveness of the monitoring of the operation status of the distribution network, and providing the possibility for quickly locating and solving problems. Using advanced algorithms to construct a geometric model and obtain key information provides a basis for deeply understanding the structure and operation characteristics of the distribution network. Accurately grasping the connected components and loop closing points of the distribution network helps optimize the grid layout, improve power transmission efficiency, reduce energy losses, and lower operating costs. By using advanced methods for power flow analysis and prediction, the current steady-state current situation can be accurately grasped, and the future steady-state current can be reliably predicted. This provides a scientific basis for the planning and scheduling of the distribution network, enabling the operating strategy to be adjusted in advance to avoid problems such as equipment overload and aging caused by abnormal steady-state current, extending the service life of the equipment, and reducing maintenance and replacement costs. By constructing a simulation model and applying professional methods to analyze the transient process and change trend, the characteristics of the impact current can be deeply understood. Thus, targeted protection measures can be taken to reduce the risk of damage to equipment caused by the impact current, enhancing the anti-interference ability and stability of the distribution network. By setting safety thresholds and triggering alarms when the current is abnormal, the operation and maintenance personnel can be reminded in a timely manner. Ensuring that measures are taken promptly when the current exceeds the safe range to avoid the expansion of accidents and guarantee the safety of personnel and equipment. Reducing the power outage time and scope, improving power supply reliability, enhancing user satisfaction, and providing strong support for the stable development of the social economy.

[0086] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0087] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A distribution network loop closing steady-state current and impact current analysis and calculation system, characterized in that Including: A data acquisition module, which is used to collect the operation data of the distribution network in real time and preprocess the operation data to obtain preprocessed data; A modeling and analysis module, which is used to build a geometric model based on the finite element analysis method, implement a depth-first search algorithm to obtain the connected components of the distribution network, and use the minimum spanning tree algorithm to identify the location information of the loop closing points; A steady-state current analysis module, which is used to perform power flow analysis on the geometric model according to the Newton-Raphson method and the power flow calculation iteration technique to obtain the current steady-state current, and build a prediction model based on the support vector machine. Input the preprocessed data, the connected components, the location information of the loop closing points and the current steady-state current, and output the predicted steady-state current; An impact current analysis module, which is used to build a circuit simulation model, obtain the behavioral characteristics of the impact current, and analyze the change trend of the impact current using the finite difference method; A safety warning module, which is used to set the safety thresholds of the steady-state current and the impact current. If the current steady-state current, the predicted steady-state current value or the impact current exceeds the set threshold, an alarm system is triggered.

2. The analysis and calculation system for steady-state current and impact current of distribution network loop closing according to claim 1, characterized in that The data acquisition module includes a real-time monitoring unit; the real-time monitoring unit is used to collect the operation data of the distribution network in real time through data acquisition devices, and the operation data includes voltage data, current data, power data and frequency data.

3. The analysis and calculation system for the steady-state current and inrush current of the distribution network loop closing according to claim 1, characterized in that, The data acquisition module further includes a data preprocessing unit; The data preprocessing unit is used to preprocess the collected operation data, and the process includes: Using the Kalman filter algorithm to remove the random noise in the operation data, and using the Z-score method to identify and remove the outliers in the operation data; Using the moving average method to smooth the operation data, and using data normalization to convert the operation data to a unified range; Using the interpolation method to process the missing values in the operation data to obtain a complete data set, and using the complete data set as the preprocessed data.

4. The analysis and calculation system for the steady-state current and impact current of network closing loop according to claim 1, wherein, The process of building a geometric model based on the finite element analysis method includes: Setting physical characteristics and electrical behaviors, where the physical characteristics include current distribution and temperature field, and the electrical behaviors include steady-state current and local voltage changes; Collecting the design parameters of the distribution network, where the design parameters include the specifications of basic components, combining the preprocessed data, and using the finite element analysis method to build a geometric model of the distribution network, and drawing the basic components in the geometric model, where the basic components include connecting wires, switches, transformers and loads; Assigning preset material properties to each component in the geometric model, where the material properties include conductivity, permittivity and thermal conductivity, and inputting the material properties into the geometric model; Selecting the quadrilateral element type and dividing the geometric model into finite element meshes; Setting boundary conditions, where the boundary conditions include fixed ends, symmetry planes, voltage sources and current sources, and applying external loads to simulate the operation state of the distribution network, where the external loads include current input and heat sources; Using a dynamic analysis solution algorithm, configuring solution parameters, and obtaining the current distribution data and voltage distribution data of the geometric model, where the solution parameters include convergence criteria and time steps.

5. The analysis and calculation system for steady-state current and impulse current of distribution network loop closing according to claim 4, characterized in that The process of obtaining the connected components of a distribution network by implementing a depth-first search algorithm includes: Regarding the transformer, the load, and the switch as nodes in the distribution network topology data, and regarding the connecting lines as edges in the distribution network topology data; Converting the distribution network into a graph model, where nodes represent electrical equipment and edges represent electrical connections, and using an adjacency matrix to represent the structure of the graph model; Creating an empty set, defining a depth-first search function, taking the current node, the structure of the graph, and the set of visited nodes as parameters of the depth-first search function, adding the current node to the empty set and marking it as visited, traversing all adjacent nodes of the current node, and for each unvisited adjacent node, recursively calling the depth-first search function; If the adjacent node of a node has been visited, it indicates the existence of a connection path. Traverse all nodes in the graph model to obtain all connected components.

6. The analysis and calculation system for steady-state current and impact current of distribution network loop closing according to claim 1, wherein, The process of identifying the location information of the loop closing point by using the minimum spanning tree algorithm includes: Creating an empty minimum spanning tree set, using a priority queue to store edges and sorting them according to weights, where the weights include resistance and distance. Taking one end node of the edge with the minimum weight as the starting node, adding the starting node to the minimum spanning tree set and marking it as having been added to the minimum spanning tree; Adding the edge with the minimum weight and its second node that is not in the tree to the minimum spanning tree, marking the second node as having been added to the minimum spanning tree set, and adding all edges connected to the second node to the priority queue; Taking the second node after adding to the minimum spanning tree set as the new starting node, adding the new edge connected to the new starting node and the next node connected by the new edge to the minimum spanning tree, marking the next node as having been added to the minimum spanning tree set, and adding all edges connected to the next node to the priority queue; Until all nodes are added to the minimum spanning tree, the node that forms a loop connection between the node connected to the existing tree and the already connected node when added to the minimum spanning tree set is the loop closing point.

7. The analysis and calculation system for the steady-state current and inrush current of the distribution network loop closing according to claim 1, characterized in that, The process of performing power flow analysis on the geometric model according to the Newton-Raphson method and the power flow calculation iteration technique includes: Obtaining the initial voltage value and initial current value of the geometric model, and setting convergence conditions, where the convergence conditions include voltage change tolerance; Constructing a Jacobian matrix based on the distribution network topology data combined with the preprocessing data, using the loop closing point voltage data and the partial derivatives of the loop closing point power equation as elements of the Jacobian matrix; Converting the power flow calculation into a system of nonlinear equations, where the system of nonlinear equations includes the loop closing point power balance equation; Updating the loop closing point voltage using the Newton-Raphson iteration formula, checking whether the change in the loop closing point voltage meets the set convergence conditions. If the conditions are met, it is judged as having converged; Obtaining the current steady-state current according to the loop closing point voltage value and the loop closing point power balance equation.

8. The analysis and calculation system for steady-state current and impact current of distribution network loop closing according to claim 1, wherein, The process of constructing a prediction model based on a support vector machine includes: Collect historical operation data of each node in the distribution network, and obtain the historical connected components, historical loop closing point location information, and historical steady-state current of the distribution network according to the historical operation data, and label the steady-state current at the next moment corresponding to the historical steady-state current; Construct a support vector machine basic model using a polynomial kernel function. Use the historical operation data, the historical connected components, the historical loop closing point location information, and the historical steady-state current as inputs, and the steady-state current at the next moment as the output to train the basic model, and retain the model parameters that meet the accuracy rate to obtain a prediction model.

9. The analysis and calculation system for the steady-state current and impact current of the distribution network loop closing according to claim 1, characterized in that The impact current analysis module includes a circuit simulation model unit and a change trend acquisition unit; the circuit simulation model unit is used to construct a circuit simulation model using a preset circuit simulation tool to simulate the behavioral characteristics of the impact current in the distribution network, and the behavioral characteristics include current waveform, current peak value, and current frequency; the change trend acquisition unit is used to establish a time-domain differential equation describing the impact current according to the physical characteristics of the distribution network, and the physical characteristics include inductance, capacitance, and resistance; perform Laplace transform on the time-domain differential equation to convert the time-domain differential equation into a frequency-domain equation; represent the Laplace transform relationship between the input voltage and the output current as a transfer function; through inverse Laplace transform, convert the transfer function of the frequency-domain equation into a time-domain equation to obtain the time-domain response of the impact current; discretize the time-domain response in time, define a discrete time step, and generate a discrete time series; according to the discretization, use the finite difference method to convert the time-domain equation into a discrete form; solve the current values in the discrete time series and analyze the change trend of the impact current over time.

10. The analysis and calculation system for steady-state current and impact current of distribution network loop closing according to claim 1, wherein, The safety threshold includes the maximum allowable steady-state current value and the maximum allowable impact current behavioral characteristic value.

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