Grid structure configuration method and system for distribution network lines

Abstract

The present invention discloses a grid structure configuration method and system for a distribution network line. By collecting contact pressure data, partial discharge data, basic structural parameters, etc. of a sectional switch in the distribution network line, these data are used to obtain a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures, a second influence degree value of the switch displacement change on the line transmission characteristics, and a transmission power value of a contact path. Finally, the first influence degree value, the second influence degree value, and the transmission power value of the contact path are used to obtain an optimal state combination of all sectional switches in the grid reconstruction of the distribution network. This optimal state combination can then be used to configure the grid structure. The present invention realizes a comprehensive analysis of the switch state, the line transmission characteristics, and the network topology structure. While ensuring the safe and reliable operation of the distribution network, it provides important technical support for the operation and maintenance of the distribution network and the grid reconstruction.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and in particular to a grid structure configuration method and system for power distribution network lines. Background Art

[0002] During the operation of the distribution network line section switch, the contact pressure directly affects the contact area and contact resistance. Lower contact pressure will lead to a smaller contact area and current concentration, thus forming a higher current density on the contact surface. This high current density area will produce a stronger magnetic field and cause uneven distribution of contact flux density. After long-term operation, the contact surface will inevitably wear and oxidize, further exacerbating the uneven current distribution and making the local magnetic flux density of the contact too high. When micro-arcs are generated on the contact surface due to local discharge, the contact resistance will change dynamically. The generation and extinction of micro-arcs is a rapid process, which will cause the contact resistance to fluctuate in a short period of time. This dynamic change in contact resistance will cause the dynamic impedance characteristics of the switch body to change accordingly.

[0003] For distribution networks containing multiple segmented switches, it is necessary to evaluate the reliability and effectiveness of different communication paths when reconfiguring the grid. Traditional path evaluation methods mainly consider the static parameters of the line, however, the impact of the dynamic changes of the segmented switches is often ignored. How to accurately describe the complex relationship between the transmission characteristics of the segmented switches and the contact pressure, partial discharge, and contact resistance changes, and incorporate them into the evaluation of the communication paths for grid reconstruction, is an important consideration in the distribution network reconstruction process. If the impact of contact pressure, partial discharge, and contact resistance changes on the transmission characteristics of the segmented switches is ignored, the transmission capacity evaluation of the communication paths will be inaccurate, thus affecting the effectiveness and safety of the grid reconstruction scheme. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a grid structure configuration method and system for distribution network lines, which realizes the comprehensive analysis of switch status, line transmission characteristics and network topology structure, and provides important technical support for distribution network operation and maintenance and grid reconstruction while ensuring the safe and reliable operation of the distribution network.

[0005] To achieve the above object, an embodiment of the present invention provides a method for configuring a grid structure of a power distribution network line, comprising:

[0006] Obtain contact pressure data of all section switches in the distribution network at different contact pressures, partial discharge data on the contact surface, basic structural parameters, and transmission power values ​​of the contact paths in the distribution network grid reconstruction environment;

[0007] Obtaining, according to the contact pressure data, a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures;

[0008] Obtaining a change rule of the contact resistance of the segment switch during partial discharge according to the partial discharge data;

[0009] According to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristic is obtained;

[0010] According to the first impact degree value, the second impact degree value and the transmission power value of the connection path, a target state combination of all section switches in the distribution network grid reconstruction environment is obtained;

[0011] The target state combination of the segment switches is used to configure the grid structure.

[0012] As an improvement of the above solution, the method of obtaining the transmission power value of the connection path in the distribution network grid reconstruction environment includes:

[0013] Obtain the electrical parameters and topological structure of the interconnection path in the distribution network reconstruction environment;

[0014] Obtaining power distribution data of the communication path according to the electrical parameters and the topological structure;

[0015] The power distribution data is used to determine a transmission power value of the communication path.

[0016] As an improvement of the above solution, the step of obtaining a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures according to the contact pressure data includes:

[0017] Using tetrahedral mesh to divide the contact structure of the sectional switch to obtain a mesh model of the contact structure;

[0018] respectively setting the pressure data of the grid model according to the corresponding contact pressure data, and setting the magnetic permeability of the grid model according to the electromagnetic characteristics of the segment switch;

[0019] Calculate the magnetic field distribution data inside the contact structure and the current density distribution data on the contact surface;

[0020] Obtaining magnetic flux density distribution data of each grid in the grid model according to the magnetic field distribution data and the current density distribution data;

[0021] Fitting the magnetic flux density distribution data of each grid to obtain a magnetic flux density distribution curve;

[0022] The magnetic flux density distribution curve is compared with a preset uniform distribution curve to obtain a first influence degree value of the segment switch on the contact magnetic flux density distribution at different contact pressures.

[0023] As an improvement of the above solution, the magnetic flux density distribution curve is compared with a preset uniform distribution curve to obtain a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures, including:

[0024] Calculating the standard deviation of the magnetic flux density distribution curve and the uniform distribution curve;

[0025] Calculate the magnetic flux density distribution unevenness index corresponding to different contact pressures according to the standard deviation and the average value of the magnetic flux density;

[0026] A first influence degree value of different contact pressures on the contact point magnetic flux density distribution is determined according to the magnetic flux density distribution unevenness index.

[0027] As an improvement of the above scheme, the partial discharge data includes current data and voltage data on the contact surface when a micro-arc is generated during partial discharge; the change law of the contact resistance of the section switch during partial discharge is obtained according to the partial discharge data, including:

[0028] Determine the contact resistance of the segment switch during partial discharge according to the current data and the voltage data, and determine the contact resistance change rate;

[0029] When the contact resistance change rate exceeds a preset change rate threshold, it is determined that abnormal discharge occurs in the contact of the section switch;

[0030] The contact resistance change rate of the contact during abnormal discharge is recorded to obtain the change law of the contact resistance of the section switch during partial discharge.

[0031] As an improvement of the above solution, according to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristics is obtained, including:

[0032] According to the basic structural parameters and the change law of the contact resistance, a dynamic impedance characteristic curve and a transient impedance characteristic curve of the segment switch are obtained;

[0033] According to the dynamic impedance characteristic curve and the transient impedance characteristic curve, a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic is obtained.

[0034] As an improvement of the above scheme, the basic structural parameters include geometric structural parameters and material property parameters of the segment switch; the dynamic impedance characteristic curve and transient impedance characteristic curve of the segment switch are obtained according to the variation law of the basic structural parameters and the contact resistance, including:

[0035] Establishing a three-dimensional electromagnetic field model of the segment switch according to the geometric structure parameters, the material property parameters and the change law of the contact resistance;

[0036] Using the electromagnetic field distribution in the three-dimensional electromagnetic field model, a dynamic impedance characteristic curve of the segmented switch under different contact resistances is obtained;

[0037] Obtain impedance amplitude and phase data corresponding to the transmission line at different frequencies according to the dynamic impedance characteristic curve;

[0038] The impedance amplitude and the phase data are fitted to obtain a corresponding transient impedance characteristic curve.

[0039] As an improvement of the above solution, obtaining a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic according to the dynamic impedance characteristic curve and the transient impedance characteristic curve includes:

[0040] Extracting data from the dynamic impedance characteristic curve and the transient impedance characteristic curve respectively according to a preset window length, obtaining a plurality of first reference impedances corresponding to the dynamic impedance characteristic curve, and obtaining a plurality of second reference impedances corresponding to the transient impedance characteristic curve;

[0041] Calculating an average reference impedance of the first reference impedance and the corresponding second reference impedance;

[0042] inputting the average reference impedance into the three-dimensional electromagnetic field model, and adjusting the displacement of the segment switch in the three-dimensional electromagnetic field model;

[0043] The impedance change amount of the segment switch when different displacements are generated is recorded to obtain a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic.

[0044] As an improvement of the above solution, the target state combination of all section switches in the distribution network grid reconstruction environment is obtained according to the first impact degree value, the second impact degree value and the transmission power value of the connection path, including:

[0045] Acquire a reference state combination of all sectionalizers in the distribution network; wherein each reference state combination includes at least one first sectionalizer in a closed state and at least one second sectionalizer in an open state;

[0046] Obtaining first influence degree values, second influence degree values, and transmission power values ​​of the communication paths corresponding to all first segment switches in each reference state combination;

[0047] For each reference state combination, a weighted sum is performed according to the first impact degree value, the second impact degree value, and the transmission power value of the communication path to obtain a combined score for each reference state combination;

[0048] At least one reference state combination whose combined score meets a preset score condition is selected from each reference state combination as a target state combination.

[0049] To achieve the above-mentioned purpose, an embodiment of the present invention further provides a grid structure configuration system for a power distribution network line, comprising:

[0050] Several section switches are installed in the distribution network lines;

[0051] A contact pressure data acquisition device is used to collect contact pressure data of all section switches in the distribution network at different contact pressures;

[0052] A partial discharge data acquisition device is used to collect partial discharge data on the contact surfaces of all section switches in the distribution network line;

[0053] Controller for:

[0054] Acquiring contact pressure data of the section switch, partial discharge data on the contact surface, basic structural parameters and transmission power value of the contact path in the distribution network grid reconstruction environment;

[0055] Obtaining, according to the contact pressure data, a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures;

[0056] Obtaining a change rule of the contact resistance of the segment switch during partial discharge according to the partial discharge data;

[0057] According to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristic is obtained;

[0058] According to the first impact degree value, the second impact degree value and the transmission power value of the connection path, a target state combination of all section switches in the distribution network grid reconstruction environment is obtained;

[0059] The target state combination of the segment switches is used to configure the grid structure.

[0060] Compared with the prior art, the grid structure configuration method and system of the distribution network line disclosed in the present invention collects contact pressure data, partial discharge data, basic structural parameters, etc. of the segmented switch in the distribution network line, and uses these data to obtain the first influence degree value of the segmented switch on the contact magnetic flux density distribution at different contact pressures, the second influence degree value of the switch displacement change on the line transmission characteristics, and the transmission power value of the communication path. Finally, the first influence degree value, the second influence degree value and the transmission power value of the communication path are used to obtain the optimal state combination of all segmented switches in the distribution network grid reconstruction environment, and then the grid structure can be configured using this optimal state combination. The present invention realizes a comprehensive analysis of the switch state, line transmission characteristics and network topology structure, and provides important technical support for the operation and maintenance of the distribution network and grid reconstruction while ensuring the safe and reliable operation of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a flow chart of a grid structure configuration method of a distribution network line provided by an embodiment of the present invention;

[0062] Figure 2 is a flow chart of determining the maximum transmission power value of a communication path provided by an embodiment of the present invention;

[0063] Figure 3 is a flow chart for determining a first influence degree value of a section switch on a contact magnetic flux distribution density at different contact pressures provided by an embodiment of the present invention;

[0064] Figure 4 is another flow chart for determining a first influence degree value of a section switch on a contact magnetic flux distribution density at different contact pressures provided by an embodiment of the present invention;

[0065] Figure 5 is a flow chart for determining the change rule of the contact resistance of a segment switch during partial discharge provided by an embodiment of the present invention;

[0066] Figure 6 is a flow chart for determining a second influence degree value of a switch displacement change on a line transmission characteristic provided by an embodiment of the present invention;

[0067] Figure 7 is a flow chart of determining a target state combination provided by an embodiment of the present invention;

[0068] Figure 8 It is a structural block diagram of a grid structure configuration system for a distribution network line provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0069] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] See also Figure 1 , Figure 1 1 is a flow chart of a grid structure configuration method for a distribution network line provided by an embodiment of the present invention, the method comprising:

[0071] S1. Obtain contact pressure data of all section switches in the distribution network at different contact pressures, partial discharge data on the contact surface, basic structural parameters and transmission power values ​​of the contact paths in the distribution network grid reconstruction environment;

[0072] S2. Obtaining a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures according to the contact pressure data;

[0073] S3, obtaining a change rule of the contact resistance of the segment switch during partial discharge according to the partial discharge data;

[0074] S4. Obtaining a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristics according to the change law of the basic structural parameters and the contact resistance;

[0075] S5. Obtain a target state combination of all section switches in a distribution network framework reconstruction environment according to the first impact degree value, the second impact degree value, and the transmission power value of the connection path;

[0076] S6. Utilizing the target state combination of the segment switches to configure the grid structure.

[0077] Exemplarily, by collecting contact pressure data, partial discharge data, basic structural parameters, etc. of the segmented switch in the distribution network line, these data are used to obtain the first influence degree value of the segmented switch on the contact magnetic flux density distribution at different contact pressures, the second influence degree value of the switch displacement change on the line transmission characteristics and the transmission power value of the communication path. Finally, the first influence degree value, the second influence degree value and the transmission power value of the communication path are used to evaluate all combinations of the segmented switches in the distribution network one by one, and the optimal state combination of all segmented switches in the distribution network grid reconstruction environment is obtained. This optimal state combination can then be used to configure the grid structure. The present invention realizes a comprehensive analysis of the switch state, line transmission characteristics and network topology structure, and provides important technical support for the operation and maintenance of the distribution network and the grid reconstruction while ensuring the safe and reliable operation of the distribution network.

[0078] Specifically, in step S1, the present invention needs to obtain the following four types of data:

[0079] 1) Contact pressure data of all section switches at different contact pressures. The contact pressure data are collected by means of a contact pressure sensor array.

[0080] 2) Partial discharge data on the contact surfaces of all section switches. The current and voltage sensor arrays are used to obtain the current and voltage signals of the partial discharge points on the contact surfaces.

[0081] 3) Basic structural parameters of all section switches. By querying the model of each section switch in the distribution network, the corresponding basic structural parameters can be obtained. The basic structural parameters include the geometric structural parameters and material property parameters of the section switch; wherein the geometric structural parameters may include the dimensions of the contact insulation shell and the conductive arm structure; the material property parameters may be extracted from the material manual, including the dielectric constant and magnetic permeability of the contact insulation material.

[0082] 4) Transmission power value of the interconnection path in the distribution network reconstruction environment. The distribution network interconnection path refers to the connection path set up between different distribution networks to improve the reliability of power supply. These interconnection paths can supply power to the affected areas through other paths when the main network fails, thereby reducing the scope of power outage.

[0083] Specifically, see Figure 2 , Figure 2 The flowchart of determining the maximum transmission power value of the communication path provided by an embodiment of the present invention, wherein obtaining the transmission power value of the communication path in the distribution network grid reconstruction environment includes:

[0084] S11, obtaining electrical parameters and topological structure of the connection path in the distribution network grid reconstruction environment;

[0085] S12, obtaining power distribution data of the communication path according to the electrical parameters and the topological structure;

[0086] S13. Determine the transmission power value of the communication path using the power distribution data.

[0087] Exemplarily, the electrical parameters of the communication path reflect the basic transmission characteristics of the line. The electrical parameters include voltage, current, resistance, etc. The topological structure reflects the path location of each segment switch. The power of each path in the distribution network line in the on state (that is, the segment switch of the path is closed) can be calculated through the collected electrical parameters and topological structure, and then the power distribution data of the communication path can be obtained. According to all the segment switches in the distribution network line, all state combinations of these segment switches are determined. Each state combination needs to meet the normal working conditions of the distribution network. In these combinations, some of the segment switches are disconnected, and another part of the segment switches are closed. Each state combination is measured once to obtain the transmission power value of the communication path of the distribution network under different state combinations.

[0088] Specifically, in step S2, see Figure 3 , Figure 3 This is a flow chart of determining a first influence degree value of a sectionalizing switch on a contact magnetic flux distribution density at different contact pressures provided by an embodiment of the present invention, wherein step S2 specifically includes:

[0089] S21, using a tetrahedral mesh to divide the contact structure of the sectional switch to obtain a mesh model of the contact structure;

[0090] S22, setting the pressure data of the grid model according to the corresponding contact pressure data, and setting the magnetic permeability of the grid model according to the electromagnetic characteristics of the segment switch;

[0091] S23, calculating magnetic field distribution data inside the contact structure and current density distribution data on the contact surface;

[0092] S24, obtaining magnetic flux density distribution data of each grid in the grid model according to the magnetic field distribution data and the current density distribution data;

[0093] S25, fitting the magnetic flux density distribution data of each grid to obtain a magnetic flux density distribution curve;

[0094] S26. Compare the magnetic flux density distribution curve with a preset uniform distribution curve to obtain a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures.

[0095] It should be noted that the function of the contact is to connect or disconnect the controlled circuit; magnetic flux density is another name for magnetic induction intensity, which indicates the number of magnetic lines of force that pass vertically through a unit area and is proportional to the voltage. For a segmented switch, the smaller the impact on the contact magnetic flux density distribution under different contact pressures, the better the situation, indicating that the performance of this segmented switch will not be affected by the contact pressure. Therefore, steps S21 to S26 are to find the impact of each segmented switch on the contact magnetic flux density distribution under different contact pressures. The smaller the impact of the segmented switch, the greater the possibility of subsequent classification into the target state combination to configure the grid structure.

[0096] Exemplarily, in steps S21-S22, after obtaining the contact pressure data collected in real time, it is necessary to pre-process the contact pressure data collected in real time, such as using interpolation to fill in missing data and eliminating obviously erroneous data (such as data greater than the maximum pressure threshold, or less than the maximum pressure threshold). For each segmented switch, the sampling frequency of each pressure sensor is set to 100Hz, and a segmented switch is set at least two sampling data points in its contact part, and one sampling data point corresponds to one pressure sensor. Tetrahedral meshing is the process of dividing a three-dimensional geometric body into tetrahedral units to facilitate various applications such as finite element analysis, computer graphics learning, and robot control technology. In the embodiment of the present invention, the contact structure of the segmented switch is divided by tetrahedral meshing, and the minimum mesh size can be set to 1mm. After obtaining the mesh model of the contact structure, for each mesh of the mesh model, the pressure data of each mesh can be set using the previously collected contact pressure data. At the same time, the magnetic permeability of each mesh is set according to the electromagnetic properties of the contact material.

[0097] Exemplarily, in step S23, in the grid model, a mathematical model of the magnetic scalar potential equation and Ampere's loop law is established. The magnetic scalar potential equation is a mathematical equation used to describe the magnetic field distribution. By solving the magnetic scalar potential equation, the magnetic field distribution data inside the contact structure is obtained. At the same time, Ampere's loop law characterizes the law of basic characteristics in a constant magnetic field. It describes the loop integral characteristics of the magnetic field intensity. By solving Ampere's loop law, the current density distribution data on the contact surface can be obtained. Among them, the magnetic scalar potential equation can refer to the construction process of the magnetic scalar potential in the prior art (such as the solution process of the Poisson equation), or, an embodiment of the present invention provides a schematic diagram of a magnetic scalar potential equation, and the schematic diagram of the magnetic scalar potential equation satisfies the following formula:

[0098] (1);

[0099] Among them, the molecular current is regarded as a magnetic dipole composed of a pair of imaginary magnetic charges, and the imaginary magnetic charge distribution appears after the material is magnetized. It is a gradient operator. The gradient operator is used to calculate the strength and direction of the magnetic field. The gradient operator is related to the distribution of the grid. Since the contact is a curved surface, the actual contact area distributed in each grid is different during division. Therefore, the magnetic field strength and direction corresponding to different grids are different. is the magnetic permeability; is the magnetic scalar potential; is the measured current of the current grid. Under different contact pressures, the current distribution of the contact is uneven due to the different contact resistance at the local position of the contact. Therefore, dividing the contact into grids and then calculating its magnetic scalar potential can more accurately obtain the overall magnetic field distribution of the contact.

[0100] Among them, Ampere's loop law can also refer to the construction process of Ampere's loop law in the prior art, or, the embodiment of the present invention provides a schematic diagram of a mathematical model of Ampere's loop law, which satisfies the following formula:

[0101] (2);

[0102] Wherein, formula (2) is the differential form of Ampere's circuit law obtained according to the Kelvin-Stokes theorem. is the magnetic constant, which is a preset fixed value; is the current density; B is the magnetic field intensity; represents the curl of magnetic field B. Formula (2) indicates that the curl of magnetic field B is equal to the conduction current density that generates the magnetic field. It should be noted that the curl of magnetic field is a physical quantity that describes the rotation characteristics of magnetic field. It indicates the degree of rotation of magnetic field lines around a point (i.e., grid) in the magnetic field. The size of the curl can be calculated by the curl operator To calculate, specifically, the curl operator It is the product of the magnetic field strength vector and the position vector.

[0103] Exemplarily, in step S24, the magnetic flux density distribution data of each grid in the grid model is obtained according to the magnetic field distribution data and the current density distribution data. For example, the magnetic field distribution data and the current density distribution data can be directly multiplied as the magnetic flux density distribution data of the current grid.

[0104] Specifically, in steps S25-S26, the magnetic flux density distribution data of each grid is summarized. For example, for the same contact pressure data, the sum of the magnetic flux density distribution data of all grids is taken. At this time, one contact pressure data corresponds to the sum of the magnetic flux density distribution data. After fitting, the magnetic flux density distribution curve under different contact pressures can be obtained. The magnetic flux density distribution curve obtained by actual measurement is compared with the preset uniform distribution curve, which is a correlation curve that characterizes the contact pressure and magnetic flux density distribution data under ideal conditions. Taking the same contact pressure data in the two curves as the benchmark, the difference between the two curves is compared. The greater the difference, the greater the influence of the contact pressure of the segmented switch on the magnetic flux density distribution data.

[0105] Further, see Figure 4 , Figure 4 is another flow chart for determining the first influence degree value of the sectionalizer on the contact magnetic flux distribution density at different contact pressures provided by an embodiment of the present invention, wherein step S26 specifically includes:

[0106] S261, calculating the standard deviation of the magnetic flux density distribution curve and the uniform distribution curve;

[0107] S262, calculating the magnetic flux density distribution unevenness index corresponding to different contact pressures according to the standard deviation and the average value of the magnetic flux density;

[0108] S263. Determine a first influence degree value of different contact pressures on contact magnetic flux density distribution according to the magnetic flux density distribution unevenness index.

[0109] Exemplarily, in step S261, the calculation formula of the standard deviation of the magnetic flux density distribution curve and the uniform distribution curve satisfies:

[0110] (3);

[0111] in, is the standard deviation; is the total number of measurement points. The measurement points are based on the same contact pressure data in the magnetic flux density distribution curve and the uniform distribution curve. The corresponding magnetic flux density distribution data for the same contact pressure data; For the The difference between the magnetic flux density distribution data corresponding to the magnetic flux density distribution curve and the uniform distribution curve, .

[0112] Exemplarily, in steps S262-S263, the average magnetic flux density is indivual The average value of the magnetic flux density distribution unevenness index is equal to the ratio of the standard deviation to the average value of the magnetic flux density, and the magnetic flux density distribution unevenness index is used to characterize the first influence degree value of the current segment switch on the contact magnetic flux density distribution under different contact pressure data.

[0113] Specifically, in step S3, see Figure 5 , Figure 5 The flowchart of determining the change law of the contact resistance of the sectionalizer during partial discharge provided by an embodiment of the present invention, wherein the partial discharge data includes the current data and the voltage data of the contact surface when the partial discharge generates a micro-arc, and step S3 specifically includes:

[0114] S31, determining the contact resistance of the segment switch during partial discharge according to the current data and the voltage data, and determining the contact resistance change rate;

[0115] S32, when the contact resistance change rate exceeds a preset change rate threshold, it is determined that abnormal discharge occurs at the contact of the section switch;

[0116] S33, recording the contact resistance change rate of the contact during abnormal discharge, and obtaining the change rule of the contact resistance of the section switch during partial discharge.

[0117] Exemplarily, in steps S31 to S33, the contact resistance can be calculated based on the current data and the voltage data. After the contact resistance is calculated, the contact resistance change rate of each cycle can be obtained in combination with the time period. Further, since only the current data and voltage data of a period of time are collected in the acquisition stage, the calculated contact resistance data is very small. Therefore, after the contact resistance is calculated based on the collected current data and voltage data, a mapping relationship with the contact resistance is established. Further, based on this mapping relationship, the change trend of the contact resistance over time can be obtained. According to the preset time period, the value is taken in the prediction result (which can be a curve), and the change rate of the contact resistance in this time period is calculated. When it is detected that the contact resistance change rate of a certain time period exceeds the change rate threshold (preset according to the empirical value), it indicates that the contact of the segment switch has abnormal discharge. At this time, the contact resistance change rate in all time periods with abnormal discharge is recorded, and this data is used as the change law of the contact resistance of the segment switch during partial discharge.

[0118] Specifically, in step S4, see Figure 6 , Figure 6 is a flow chart of determining a dynamic impedance characteristic curve and a transient impedance characteristic curve provided by an embodiment of the present invention, wherein step S4 specifically includes:

[0119] S41, obtaining a dynamic impedance characteristic curve and a transient impedance characteristic curve of the segment switch according to the basic structural parameters and the change rule of the contact resistance;

[0120] S42. Obtain a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic according to the dynamic impedance characteristic curve and the transient impedance characteristic curve.

[0121] Specifically, step S41 specifically includes: establishing a three-dimensional electromagnetic field model of the segmented switch according to the variation law of the geometric structure parameters, the material property parameters and the contact resistance; obtaining the dynamic impedance characteristic curve of the segmented switch under different contact resistances using the electromagnetic field distribution in the three-dimensional electromagnetic field model; obtaining the impedance amplitude and phase data corresponding to the transmission line at different frequencies according to the dynamic impedance characteristic curve; fitting the impedance amplitude and the phase data to obtain the corresponding transient impedance characteristic curve.

[0122] It should be noted that the impedance characteristics directly reflect the degree of deterioration of the contact state. The accurate assessment of the contact state is achieved by monitoring the dynamic impedance characteristic curve. The transient impedance characteristic curve is obtained by further sorting the dynamic impedance characteristic curve, which can be understood as a more idealized dynamic impedance characteristic curve. The introduction of the transient impedance characteristic curve can make up for the incorrect impedance data caused by errors in the three-dimensional electromagnetic field model.

[0123] Exemplarily, according to the dimensions of the contact insulation shell and the conductive arm structure, as well as the dielectric constant and magnetic permeability of the contact insulation material, and the change law of the contact resistance, a three-dimensional electromagnetic field model of the segmented switch is established to simulate the transmission characteristics of the segmented switch during abnormal discharge. The voltage and current values ​​of the switch body are extracted according to the electromagnetic field distribution data, the frequency domain data of the voltage and current are calculated by discrete Fourier transform, the impedance amplitude and phase of the switch body at different frequency points are calculated according to the frequency domain data, and the dynamic impedance characteristic curve is obtained by fitting the impedance values. According to the impedance amplitude and phase data of the dynamic impedance characteristic curve at different frequencies, the impedance amplitude and the phase data are fitted to obtain the corresponding transient impedance characteristic curve.

[0124] Specifically, step S42 specifically includes: extracting data in the dynamic impedance characteristic curve and the transient impedance characteristic curve according to a preset window length, obtaining a plurality of first reference impedances corresponding to the dynamic impedance characteristic curve, and obtaining a plurality of second reference impedances corresponding to the transient impedance characteristic curve; calculating the average reference impedance of the first reference impedance and the corresponding second reference impedance; inputting the average reference impedance into the three-dimensional electromagnetic field model, and adjusting the displacement of the segment switch in the three-dimensional electromagnetic field model; recording the impedance change of the segment switch when different displacements are generated, and obtaining a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristics.

[0125] It should be noted that, during the closing process of the segmented switch, contact displacement will occur, and the contact displacement will also affect the line transmission characteristics. Therefore, in the embodiment of the present invention, the impedance change of the segmented switch in different displacement states is also used to evaluate the degree of influence on the line transmission characteristics. The lower the degree of influence, the less likely the performance of the segmented switch will be affected by the contact displacement, and the greater the possibility of subsequently dividing the segmented switch into the target state combination to configure the grid structure.

[0126] Exemplarily, step S42 is a process of normalizing the data in the dynamic impedance characteristic curve and the transient impedance characteristic curve. The data in the dynamic impedance characteristic curve and the transient impedance characteristic curve are extracted once at intervals of the same window length. Assuming that the values ​​are taken n times, n first reference impedances can be obtained from the dynamic impedance characteristic curve, and n second reference impedances can be obtained from the transient impedance characteristic curve, and then the average value is calculated to obtain n average reference impedances. The n average reference impedances are input into the three-dimensional electromagnetic field model, and the three-dimensional electromagnetic field model is allowed to record the impedance change in the current state. Then, the displacement of the segment switch is adjusted in the three-dimensional electromagnetic field model (such as adjusting 1 mm each time), and the impedance change of the segment switch at different displacements is simulated. For all displacement data of the current segment switch, the average value (or sum) of all corresponding impedance changes is taken as the second influence degree value of the switch displacement change in the current segment switch on the line transmission characteristics.

[0127] Specifically, in step S5, see Figure 7 , Figure 7 is a flow chart for determining a target state combination provided by an embodiment of the present invention, wherein step S5 specifically includes:

[0128] S51, obtaining a reference state combination of all sectionalizers in the distribution network; wherein each reference state combination includes at least one first sectionalizer in a closed state and at least one second sectionalizer in an open state;

[0129] S52, obtaining the first influence degree value, the second influence degree value and the transmission power value of the communication path corresponding to all the first section switches in each reference state combination;

[0130] S53: for each reference state combination, performing weighted summation according to the first impact degree value, the second impact degree value, and the transmission power value of the communication path to obtain a combined score for each reference state combination;

[0131] S54: Filter out at least one reference state combination whose combined score meets a preset score condition from each reference state combination as a target state combination.

[0132] It should be noted that the division of the first section switch and the second section switch in the reference state combination needs to meet the normal operation of the distribution network line. For each group of reference state combinations, under the premise of considering the safety constraints of the power system, the transmission power value of the connection path under the current reference state combination is calculated, and the transmission capacity under the current switch combination is evaluated by using the transmission power value, the first impact degree value and the second impact degree value in combination with the physical parameters and operation mode of the transmission line. The transmission capacity evaluation values ​​of multiple groups of reference state combinations are compared, and the reference state combination with the best transmission capacity is selected as the target state combination for the actual operation of the power system.

[0133] Exemplarily, a weighted sum is performed based on the first impact value, the second impact value, and the transmission power value of the communication path to obtain a combined score for each reference state combination. When selecting a target state combination, the constraint needs to be satisfied: the first impact value and the second impact value are as small as possible, and the transmission power value is as large as possible. Using this constraint, the calculation process of the combined score satisfies the following formula:

[0134] (4);

[0135] in, For the The combined score of the reference state combination, , is the total number of reference state combinations; is the first weight, is the second weight, is the third weight, satisfying + + =1, the three weight values ​​can be preset, such as > > , or set to < < wait; For the The sum of the first influence degree values ​​of all first section switches of the reference state combination; For the The sum of the second influence degree values ​​of all first section switches in a reference state combination; For the The transmission power value of the communication path corresponding to the reference state combination.

[0136] Exemplarily, the preset scoring condition is one of the following: the maximum value in the combined score; the combined score is greater than a preset scoring threshold. For example, the reference state combination corresponding to the maximum combined score is selected from the combined scores as the target state combination, or the reference state combination corresponding to the combined score greater than the scoring threshold is selected as the target state combination.

[0137] Specifically, in step S6, after obtaining the target state combination, the grid structure of the distribution network is configured according to the target state combination. If there are two or more target state combinations, one of the target state combinations is selected to configure the grid structure of the distribution network, and the other is used as a candidate solution.

[0138] Compared with the prior art, the grid structure configuration method of the distribution network line disclosed in the present invention collects contact pressure data, partial discharge data, basic structural parameters, etc. of the sectional switch in the distribution network line, and uses these data to obtain the first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures, the second influence degree value of the switch displacement change on the line transmission characteristics and the transmission power value of the communication path. Finally, the first influence degree value, the second influence degree value and the transmission power value of the communication path are used to obtain the optimal state combination of all sectional switches in the distribution network grid reconstruction environment, and then the grid structure can be configured using this optimal state combination. The present invention realizes a comprehensive analysis of the switch state, line transmission characteristics and network topology structure, and provides important technical support for the operation and maintenance of the distribution network and grid reconstruction while ensuring the safe and reliable operation of the distribution network.

[0139] See also Figure 8 , Figure 8 1 is a structural block diagram of a grid structure configuration system 100 for a distribution network line provided in an embodiment of the present invention. The grid structure configuration system 100 for a distribution network line includes:

[0140] A plurality of section switches 11 are arranged in the distribution network line;

[0141] The contact pressure data acquisition device 12 is used to collect the contact pressure data of all the section switches in the distribution network at different contact pressures;

[0142] A partial discharge data acquisition device 13, used to collect partial discharge data on the contact surfaces of all section switches in the distribution network;

[0143] The controller 14 is used for:

[0144] Acquiring contact pressure data of the section switch, partial discharge data on the contact surface, basic structural parameters and transmission power value of the contact path in the distribution network grid reconstruction environment;

[0145] Obtaining, according to the contact pressure data, a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures;

[0146] Obtaining a change rule of the contact resistance of the segment switch during partial discharge according to the partial discharge data;

[0147] According to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristic is obtained;

[0148] According to the first impact degree value, the second impact degree value and the transmission power value of the connection path, a target state combination of all section switches in the distribution network grid reconstruction environment is obtained;

[0149] The target state combination of the segment switches is used to configure the grid structure.

[0150] It is worth noting that the working process of each module in the grid structure configuration system 100 of the distribution network line described in the embodiment of the present invention can refer to the working process of the grid structure configuration method of the distribution network line described in the above embodiment, and will not be repeated here.

[0151] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for configuring a grid structure of a distribution network line, characterized in that: include: Obtain contact pressure data of all section switches in the distribution network at different contact pressures, partial discharge data on the contact surface, basic structural parameters, and transmission power values ​​of the contact paths in the distribution network grid reconstruction environment; Obtaining, according to the contact pressure data, a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures; Obtaining a change rule of the contact resistance of the segment switch during partial discharge according to the partial discharge data; According to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristic is obtained; According to the first impact degree value, the second impact degree value and the transmission power value of the connection path, a target state combination of all section switches in the distribution network grid reconstruction environment is obtained; The target state combination of the segment switches is used to configure the grid structure.

2. The grid structure configuration method of the power distribution network line according to claim 1, characterized in that: The obtaining of the transmission power value of the connection path in the distribution network grid reconstruction environment includes: Obtain the electrical parameters and topological structure of the interconnection path in the distribution network reconstruction environment; Obtaining power distribution data of the communication path according to the electrical parameters and the topological structure; The power distribution data is used to determine a transmission power value of the communication path.

3. The grid structure configuration method of the power distribution network line according to claim 1, characterized in that: The step of obtaining a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures according to the contact pressure data includes: Using tetrahedral mesh to divide the contact structure of the sectional switch to obtain a mesh model of the contact structure; respectively setting the pressure data of the grid model according to the corresponding contact pressure data, and setting the magnetic permeability of the grid model according to the electromagnetic characteristics of the segment switch; Calculate the magnetic field distribution data inside the contact structure and the current density distribution data on the contact surface; Obtaining magnetic flux density distribution data of each grid in the grid model according to the magnetic field distribution data and the current density distribution data; Fitting the magnetic flux density distribution data of each grid to obtain a magnetic flux density distribution curve; The magnetic flux density distribution curve is compared with a preset uniform distribution curve to obtain a first influence degree value of the segment switch on the contact magnetic flux density distribution at different contact pressures.

4. The grid structure configuration method of the power distribution network line according to claim 3, characterized in that: The step of comparing the magnetic flux density distribution curve with a preset uniform distribution curve to obtain a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures includes: Calculating the standard deviation of the magnetic flux density distribution curve and the uniform distribution curve; Calculate the magnetic flux density distribution unevenness index corresponding to different contact pressures according to the standard deviation and the average value of the magnetic flux density; A first influence degree value of different contact pressures on the contact point magnetic flux density distribution is determined according to the magnetic flux density distribution unevenness index.

5. The grid structure configuration method of the power distribution network line according to claim 1, characterized in that: The partial discharge data includes current data and voltage data on the contact surface when a micro-arc is generated during partial discharge; the variation law of the contact resistance of the section switch during partial discharge is obtained according to the partial discharge data, including: Determine the contact resistance of the segment switch during partial discharge according to the current data and the voltage data, and determine the contact resistance change rate; When the contact resistance change rate exceeds a preset change rate threshold, it is determined that abnormal discharge occurs in the contact of the section switch; The contact resistance change rate of the contact during abnormal discharge is recorded to obtain the change law of the contact resistance of the section switch during partial discharge.

6. The grid structure configuration method of the power distribution network line according to claim 1, characterized in that: The obtaining, according to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristic comprises: According to the basic structural parameters and the change law of the contact resistance, a dynamic impedance characteristic curve and a transient impedance characteristic curve of the segment switch are obtained; According to the dynamic impedance characteristic curve and the transient impedance characteristic curve, a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic is obtained.

7. The grid structure configuration method of the power distribution network line according to claim 6, characterized in that: The basic structural parameters include geometric structural parameters and material property parameters of the segment switch; the dynamic impedance characteristic curve and transient impedance characteristic curve of the segment switch are obtained according to the basic structural parameters and the change law of the contact resistance, including: Establishing a three-dimensional electromagnetic field model of the segment switch according to the geometric structure parameters, the material property parameters and the change law of the contact resistance; Using the electromagnetic field distribution in the three-dimensional electromagnetic field model, a dynamic impedance characteristic curve of the segmented switch under different contact resistances is obtained; Acquire impedance amplitude and phase data corresponding to the transmission line at different frequencies according to the dynamic impedance characteristic curve; The impedance amplitude and the phase data are fitted to obtain a corresponding transient impedance characteristic curve.

8. The grid structure configuration method of the power distribution network line according to claim 7, characterized in that: The obtaining, according to the dynamic impedance characteristic curve and the transient impedance characteristic curve, a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic comprises: Extracting data from the dynamic impedance characteristic curve and the transient impedance characteristic curve respectively according to a preset window length, obtaining a plurality of first reference impedances corresponding to the dynamic impedance characteristic curve, and obtaining a plurality of second reference impedances corresponding to the transient impedance characteristic curve; Calculating an average reference impedance of the first reference impedance and the corresponding second reference impedance; inputting the average reference impedance into the three-dimensional electromagnetic field model, and adjusting the displacement of the segment switch in the three-dimensional electromagnetic field model; The impedance change amount of the segment switch when different displacements are generated is recorded to obtain a second influence degree value of the switch displacement change of the segment switch on the line transmission characteristic.

9. The grid structure configuration method of the power distribution network line according to claim 1, characterized in that: The step of obtaining a target state combination of all section switches in a distribution network framework reconstruction environment according to the first impact degree value, the second impact degree value, and the transmission power value of the connection path includes: Acquire a reference state combination of all sectionalizers in the distribution network; wherein each reference state combination includes at least one first sectionalizer in a closed state and at least one second sectionalizer in an open state; Obtaining first influence degree values, second influence degree values, and transmission power values ​​of the communication paths corresponding to all first segment switches in each reference state combination; For each reference state combination, a weighted sum is performed according to the first impact degree value, the second impact degree value, and the transmission power value of the communication path to obtain a combined score for each reference state combination; At least one reference state combination whose combined score meets a preset score condition is selected from each reference state combination as a target state combination.

10. A grid structure configuration system for a distribution network line, characterized in that: include: Several section switches are installed in the distribution network lines; A contact pressure data acquisition device is used to collect contact pressure data of all section switches in the distribution network at different contact pressures; A partial discharge data acquisition device is used to collect partial discharge data on the contact surfaces of all section switches in the distribution network line; Controller for: Acquiring contact pressure data of the section switch, partial discharge data on the contact surface, basic structural parameters and transmission power value of the contact path in the distribution network grid reconstruction environment; Obtaining, according to the contact pressure data, a first influence degree value of the sectional switch on the contact magnetic flux density distribution at different contact pressures; Obtaining a change rule of the contact resistance of the segment switch during partial discharge according to the partial discharge data; According to the variation law of the basic structural parameters and the contact resistance, a second influence degree value of the switch displacement variation of the segment switch on the line transmission characteristic is obtained; According to the first impact degree value, the second impact degree value and the transmission power value of the connection path, a target state combination of all section switches in the distribution network grid reconstruction environment is obtained; The target state combination of the segment switches is used to configure the grid structure.

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