Electromagnetic transient modeling method based on embedded direct current transmission

Abstract

The invention relates to an electromagnetic transient modeling method based on embedded direct current power transmission, which belongs to the technical field of electromagnetic transient modeling of a power grid, and comprises the following steps of: segmenting and distinguishing lines forming a preset power grid, counting initial sections of operation faults of each line under different conditions, and collecting fault characteristics in each initial section; forming factors corresponding to the fault features are analyzed, and a data set is generated; forming factors corresponding to the fault features are divided into current factors, voltage factors and / or resistance factors, and influence features of different factors on preset power grid operation are analyzed; according to the method, the power grid line is divided into multiple sections, different operation characteristics of the power grid line in the initial section and the subsequent multiple sections under different operation conditions can be obtained, corresponding fault forming factors are collected according to the different operation characteristics, the fault characteristics in the fault forming factors are collected, and the fault forming factors and the fault characteristics are gathered into a total electromagnetic transient model; and the efficiency and the accuracy of power grid modeling analysis calculation are improved.

Description

Technical Field

[0001] The invention relates to an electromagnetic transient modeling method based on embedded direct current power transmission, and belongs to the technical field of electromagnetic transient modeling of power grids. Background Art

[0002] Electromagnetic transients in power systems refer to transient phenomena generated by power systems when faults, switch operations, and other events occur. Transient problems in power systems mainly include short-circuit faults, switch operations, large load changes, etc. These transient problems can cause drastic changes in voltage and current, which in turn affect the stability and reliability of the power system. Among them, DC transmission technology has been widely used in long-distance and large-capacity transmission, asynchronous networking, and submarine cable transmission due to its fast and flexible power regulation, no increase in system short-circuit capacity, low loss, and small footprint. Compared with long-distance and large-capacity DC transmission technology built in traditional interconnection methods, the "embedded" DC transmission technology has its sending and receiving converter stations built within the same AC power grid, usually using the existing overhead transmission lines to "convert AC to DC" and existing or reserved AC cable channels. It can greatly improve the power grid transmission capacity and the controllability and flexibility of the power grid within the limited transmission corridor space. In order to further monitor In order to ensure the safe operation of the power grid, predictive transient modeling will be carried out for the operating indicators of the power grid. In electromagnetic transient modeling, commonly used methods include power flow calculation, state estimation, line parameter estimation, and equipment modeling. As the scale of the electromagnetic transient simulation power grid increases, the characteristics of the modeling components become more and more complex, and the requirements for simulation modeling become more and more stringent. Among them, the existing technology, when performing transient modeling of the power grid based on line parameter estimation, mostly performs comprehensive modeling based on the composed lines, and the state change of the power grid often starts from different ends. Due to the different lengths and spans of the lines, when a certain operating state change starts from a certain end, as the current is transmitted and output, the operating state of different sections of the line will also change to varying degrees. If the parameter estimates of the different component lines and the operating state changes corresponding to the parameter estimates cannot be segmented, it will affect the reliability of the power grid modeling and reduce the efficiency and accuracy of the modeling analysis and calculation. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the present invention provides an electromagnetic transient modeling method based on embedded direct current transmission, which can improve the efficiency and accuracy of power grid modeling analysis and calculation.

[0004] In order to achieve the above object, the technical solution proposed in the present invention is: an electromagnetic transient modeling method based on embedded direct current transmission, comprising:

[0005] Acquire line data of a preset power grid, divide the lines constituting the preset power grid into sections, count the starting sections where operation faults of each line occur under different conditions, collect fault features in each starting section, analyze formation factors corresponding to the fault features, and generate a data set;

[0006] Dividing the formation factors corresponding to the fault characteristics into current factors, voltage factors and resistance factors, analyzing the influence characteristics of different factors on the operation of the preset power grid, uploading the influence characteristics to the data set, and updating the data set;

[0007] Counting the duration of the influence of the current factor, voltage factor and resistance factor on the starting sections of different lines, and collecting the operation status changes of the starting sections of the lines in the corresponding time period;

[0008] Based on the current factor, voltage factor and resistance factor, the number of times each line segment fault occurs under different operating conditions is counted respectively, and the fault characteristics are collected, and the fault characteristics are aggregated to obtain the overall electromagnetic transient model of the embedded DC transmission system.

[0009] A further design of the above technical solution is as follows: the method for segmenting the line includes segmenting in equal proportion according to the length and / or span of the line, and also segmenting according to fault changes in different sections of the same line.

[0010] Obtaining line data of a preset power grid includes the following steps:

[0011] According to the electromagnetic transient simulation power grid model, the preset power grid dynamic operation calculation is performed by original parameter estimation and variable parameter estimation;

[0012] Set the parameters of the electromagnetic transient simulation power grid model before starting the simulation.

[0013] The simulation obtains the number of line components, the maximum and average length and / or span data of the lines and the load data of the preset power grid.

[0014] The parameters of the electromagnetic transient simulation power grid model are set before starting the simulation, including:

[0015] The parameter setting of the constructed electromagnetic transient simulation power grid model before starting the simulation includes selecting a parameter setting period, wherein the parameter setting period includes a peak power consumption period and a non-peak power consumption period according to the area where the preset power grid is located, wherein, in the peak power consumption period, the incremental setting is performed based on the current, voltage and resistance data collected at the historical minimum power consumption;

[0016] During the non-peak period, the setting is performed in a decreasing manner based on the current, voltage and resistance data collected during the historical maximum power consumption;

[0017] It also includes analyzing the change law of the fault parameters in each component line of the preset power grid from small to large based on the historical fault parameters of the preset power grid, and the state change characteristics of the line corresponding to the change law;

[0018] The state change characteristics of the line corresponding to the change law are used to generate a transient reference model, and the grid impedance matrix and admittance matrix are constructed based on the transient reference model, as shown below:

[0019] It is an impedance matrix;

[0020] The impedance matrix is ​​the starting line segment where the fault occurs in the preset power grid line, wherein m represents the current impedance coefficient, s represents the voltage impedance coefficient, and the impedance matrix is ​​not limited to a unit length;

[0021] It is the admittance matrix;

[0022] The admittance matrix is ​​a distinguished section other than the starting section where the fault occurs in the preset power grid line, wherein m represents the current admittance coefficient, s represents the voltage admittance coefficient, and the admittance matrix is ​​limited to a unit length;

[0023] According to the admittance matrix, the circuit load data changes in different sections of the line under the average length of the line are calculated as follows:

[0024]

[0025] Where T represents the time when the load data changes from the calculated section to the next section.

[0026] The original parameter estimation includes collecting characteristic values ​​in the current, voltage and resistance data when the historical fault of the preset power grid occurs, and pre-selecting three characteristic values ​​therein, wherein the three characteristic values ​​correspond to the low-level fault, medium-level fault and high-level fault of the preset power grid, respectively.

[0027] The variation parameter estimation is based on three different fault settings, including:

[0028] Based on the impedance coefficients in the same time period, in the same time period, the number of current impedance coefficients, voltage impedance coefficients and resistance impedance coefficients collected is counted, and each impedance coefficient collected for the first time in the time period is used as a basis, and the coefficient collected for the second time in the time period is used as a benchmark for setting;

[0029] Based on the admittance coefficient of the same time period, in different differentiated sections, the differentiated sections are divided into Among them, n represents the nth road section, and the collected The admittance coefficient of each road section is based on the admittance coefficient of the road section. The admittance coefficient after the road section changes is used as the benchmark for setting.

[0030] The updated data set is divided into a training set, a test set and a validation set. In the test set, when analyzing the impact characteristics of different factors on the operation of the preset power grid, a test period is preset, wherein each period is 3 to 5 minutes apart. In the interval, data changes including current, voltage and resistance are collected, and the impact changes are obtained based on the data changes. When the data changes of the preset power grid in the future period show an increasing trend within the interval period, it is determined that the operating state of the preset power grid is unstable. Otherwise, it is not determined.

[0031] The influencing changes include changes in circuit load of a preset power grid, and the correlation characteristics between different load changes and power consumption, line short circuit, and line length are collected. At the same time, the sections distinguished according to the load changes are marked as stable change sections and unstable change sections. In the unstable change sections, the correlation rules between the load changes and various forming factors are obtained.

[0032] An electronic device comprises a processor, an input interface, an output interface and a memory, wherein the processor, the input interface, the output interface and the memory are connected to each other, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the above-mentioned electromagnetic transient modeling method based on embedded direct current transmission.

[0033] A computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the processor executes the above-mentioned electromagnetic transient modeling method based on embedded direct current transmission.

[0034] The beneficial effects of the present invention are:

[0035] The present invention can obtain different operating characteristics of the power grid line at the starting section and subsequent sections under different operating conditions by partitioning the power grid line into multiple sections, collect corresponding fault formation factors according to different operating characteristics, collect the fault characteristics therein, and compile them into a total electromagnetic transient model. At the same time, the fault characteristics can be graded and the current, voltage and / or resistance parameters therein can be regularly adjusted. At the same time, the operating state changes of the differentiated lines are monitored within a preset time period to obtain the change rules, and then the existing state changes can be intercepted in sections when the length and span of the power grid line are different, thereby improving the efficiency and accuracy of power grid modeling analysis and calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of a method flow of an embodiment of the present invention;

[0037] Figure 2 It is a schematic diagram of the process structure of an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Embodiment 1

[0040] Reference Figure 1 and Figure 2 This embodiment provides an electromagnetic transient modeling method based on embedded direct current transmission, including:

[0041] Step S10: segment the lines constituting the preset power grid, count the starting sections where the operating faults of each line occur under different conditions, collect the fault characteristics in each starting section, analyze the formation factors corresponding to the fault characteristics, and generate a data set.

[0042] The method of segmenting the line includes segmenting in equal proportion according to the length and / or span of the line, and segmenting according to the fault changes in different sections of the same line.

[0043] Before the lines constituting the preset power grid are divided into sections, it also includes:

[0044] (1) Based on the electromagnetic transient simulation power grid model, the dynamic operation calculation of the preset power grid is performed using the original parameter estimation and the variable parameter estimation;

[0045] (2) Setting parameters of the electromagnetic transient simulation power grid model before starting the simulation, including selecting a parameter setting period, wherein the parameter setting period includes a peak power consumption period and a non-peak power consumption period according to a preset power grid region, wherein, during the peak power period, an incremental setting is performed based on the current, voltage and resistance data collected during the historical minimum power consumption;

[0046] During non-peak hours, the system includes setting the current, voltage and resistance data collected during the historical maximum power consumption in a decreasing manner;

[0047] At the same time, in the data set, the maximum data of the current, voltage and resistance data when a fault occurs in the starting section of each line is set as the first evaluation index data, and the average data is set as the second evaluation index data. In the first evaluation index data and the second evaluation index data, the values ​​in the evaluation index data set are mapped to the range of [0, 1] to obtain the standard value of the evaluation index data. According to the standard value of the evaluation index data, the proportion of the evaluation index data is analyzed.

[0048] Also includes:

[0049] Based on the historical fault parameters of the preset power grid, analyze the change rules of the fault parameters in each component line of the preset power grid from small to large, and the state change characteristics of the lines corresponding to the change rules;

[0050] The state change characteristics of the line corresponding to the change law are used to generate a transient reference model, and the grid impedance matrix and admittance matrix are constructed in the transient reference model, as shown below:

[0051] It is an impedance matrix;

[0052] The impedance matrix is ​​the starting line segment where the fault occurs in the preset power grid line, where m represents the current impedance coefficient, s represents the voltage impedance coefficient, and the impedance matrix is ​​not limited to unit length;

[0053] It is the admittance matrix;

[0054] The admittance matrix is ​​a distinguishing section other than the starting section where the fault occurs in the preset power grid line, wherein m represents the current admittance coefficient, s represents the voltage admittance coefficient, and the admittance matrix is ​​limited to unit length;

[0055] According to the admittance matrix, the circuit load data changes in different sections of the line under the condition of average line length are calculated as follows:

[0056]

[0057] Where T represents the time when the load data changes from the calculated section to the next section.

[0058] Among them, the original parameter estimation includes collecting the characteristic values ​​of the current, voltage and resistance data when the historical fault of the preset power grid occurs, and pre-selecting three characteristic values ​​therein, wherein the three characteristic values ​​correspond to the low-level fault, medium-level fault and high-level fault of the preset power grid respectively.

[0059] The estimation of the variation parameters is based on three fault settings of different degrees, and the setting methods include:

[0060] Based on the impedance coefficient of the same time period, the number of current impedance coefficient, voltage impedance coefficient and resistance impedance coefficient collected in the same time period is counted, and the impedance coefficients collected for the first time in the time period are used as the basis, and the coefficients collected for the second time in the time period are used as the benchmark for setting;

[0061] Based on the admittance coefficient of the same period, the sections are divided into Among them, n represents the nth road section, and the collected The admittance coefficient of each road section is based on the admittance coefficient of the road section. The admittance coefficient after the road section changes is used as the benchmark for setting.

[0062] (3) The number of line components, the maximum and average length and / or span data of the lines, and the load data of the preset power grid are obtained through simulation.

[0063] Step S20: dividing the formation factors corresponding to the fault characteristics into current factors, voltage factors and resistance factors, analyzing the impact characteristics of different factors on the preset power grid operation, uploading the impact characteristics to the data set, and updating the data set.

[0064] The updated data set is divided into a training set, a test set and a validation set. In the test set, when analyzing the impact characteristics of different factors on the operation of the preset power grid, a test period is preset, wherein each period is 3 to 5 minutes apart. In the interval, data changes including current, voltage and resistance are collected, and the impact changes are obtained according to the data changes. When the data changes of the preset power grid in the future period show an increasing trend within the interval period, it is determined that the operation state of the preset power grid is unstable, otherwise, it is not determined.

[0065] In this embodiment, the influencing changes include changes in circuit loads of a preset power grid, and correlation features between different load changes and power consumption, line short circuits, and line lengths are collected. At the same time, the sections are marked as stable change sections and unstable change sections according to the load changes. In the unstable change sections, the correlation rules between the load changes and various forming factors are obtained; in the correlation rules, the load change data are divided into a number of evaluation indicators, and the evaluation indicator data in the time period corresponding to the collected correlation rules are statistically calculated, the non-numerical data in the evaluation indicator data is converted into numerical data, and the data is normalized to calculate the weight of each evaluation indicator.

[0066] It should be noted that according to the operating experience of the existing power grid, the resistor will convert the current into heat or mechanical energy under load and consume it, which will affect the power factor of the power grid and reduce the efficiency of the power grid. At the same time, the presence of the resistive load will cause resistive loss. Therefore, in the load circuit, a certain voltage drop will occur, affecting the normal operation of the power grid. Especially in long-distance transmission lines, the presence of resistive loads will cause the circuit voltage to drop abnormally, resulting in line and power consumption losses. Therefore, this application includes the resistance factor while including the current and voltage in the reference range, so as to effectively analyze and predict the operating changes of different segmented lines of the preset power grid in future time periods.

[0067] Step S30: Count the duration of the influence of current factors, voltage factors and / or resistance factors on the starting sections of different lines, collect the changes in the operating status of the starting sections of the lines within the time period, generate a prediction model, and predict the relevant change trends through data.

[0068] Step S40: Based on current factors, voltage factors and / or resistance factors, the number of faults occurring in different line sections under different operating conditions is counted respectively, and fault characteristics of different faults are collected, and the fault characteristics are collected to obtain a total electromagnetic transient model of the embedded DC transmission system.

[0069] In summary, this embodiment divides the power grid line into multiple sections to obtain different operating characteristics of the power grid line in the starting section and subsequent sections under different operating conditions, collects corresponding fault formation factors according to different operating characteristics, collects the fault characteristics therein, and compiles them into an overall electromagnetic transient model, thereby improving the efficiency and accuracy of power grid modeling analysis and calculation.

[0070] Embodiment 2

[0071] This embodiment provides a terminal, including a processor, an input interface, an output interface and a memory, wherein the processor, the input interface, the output interface and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the electromagnetic transient modeling method based on embedded direct current transmission of the first embodiment.

[0072] This embodiment also provides a computer-readable storage medium, which stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, the processor executes the electromagnetic transient modeling method based on embedded direct current transmission of embodiment 1.

[0073] The technical solutions of the present invention are not limited to the above-mentioned embodiments, and any technical solutions obtained by equivalent replacement methods fall within the scope of protection required by the present invention.

Claims

1. An electromagnetic transient modeling method based on embedded direct current transmission, characterized in that: include: Acquire line data of a preset power grid, divide the lines constituting the preset power grid into sections, count the starting sections where operation faults of each line occur under different conditions, collect fault features in each starting section, analyze formation factors corresponding to the fault features, and generate a data set; Dividing the formation factors corresponding to the fault characteristics into current factors, voltage factors and resistance factors, analyzing the influence characteristics of different factors on the operation of the preset power grid, uploading the influence characteristics to the data set, and updating the data set; Counting the duration of the influence of the current factor, voltage factor and resistance factor on the starting sections of different lines, and collecting the operation status changes of the starting sections of the lines in the corresponding time period; Based on the current factor, voltage factor and resistance factor, the number of times each line segment fault occurs under different operating conditions is counted respectively, and the fault characteristics are collected, and the fault characteristics are aggregated to obtain the overall electromagnetic transient model of the embedded DC transmission system.

2. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 1 is characterized in that: The method for segmenting the line includes segmenting in equal proportion according to the length and / or span of the line, and segmenting according to the fault changes in different sections of the same line.

3. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 1 is characterized in that: Obtaining line data of a preset power grid includes the following steps: According to the electromagnetic transient simulation power grid model, the preset power grid dynamic operation calculation is performed by original parameter estimation and variable parameter estimation; Set the parameters of the electromagnetic transient simulation power grid model before starting the simulation. The simulation obtains the number of line components, the maximum and average length and / or span data of the lines and the load data of the preset power grid.

4. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 3 is characterized in that: The parameters of the electromagnetic transient simulation power grid model are set before starting the simulation, including: The parameter setting of the constructed electromagnetic transient simulation power grid model before starting the simulation includes selecting a parameter setting period, wherein the parameter setting period includes a peak power consumption period and a non-peak power consumption period according to the area where the preset power grid is located, wherein, in the peak power consumption period, the incremental setting is performed based on the current, voltage and resistance data collected at the historical minimum power consumption; During the non-peak period, the setting is performed in a decreasing manner based on the current, voltage and resistance data collected during the historical maximum power consumption; It also includes analyzing the change law of the fault parameters in each component line of the preset power grid from small to large based on the historical fault parameters of the preset power grid, and the state change characteristics of the line corresponding to the change law; The state change characteristics of the line corresponding to the change law are used to generate a transient reference model, and the grid impedance matrix and admittance matrix are constructed based on the transient reference model, as shown below: It is an impedance matrix; The impedance matrix is ​​the starting line segment where the fault occurs in the preset power grid line, wherein m represents the current impedance coefficient, s represents the voltage impedance coefficient, and the impedance matrix is ​​not limited to a unit length; It is the admittance matrix; The admittance matrix is ​​a distinguished section other than the starting section where the fault occurs in the preset power grid line, wherein m represents the current admittance coefficient, s represents the voltage admittance coefficient, and the admittance matrix is ​​limited to a unit length; According to the admittance matrix, the circuit load data changes in different sections of the line under the average length of the line are calculated as follows: Where T represents the time when the load data changes from the calculated section to the next section.

5. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 4 is characterized in that: The original parameter estimation includes collecting characteristic values ​​in the current, voltage and resistance data when the historical fault of the preset power grid occurs, and pre-selecting three characteristic values ​​therein, wherein the three characteristic values ​​correspond to the low-level fault, medium-level fault and high-level fault of the preset power grid, respectively.

6. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 5 is characterized in that: The variation parameter estimation is based on three different fault settings, including: Based on the impedance coefficients in the same time period, in the same time period, the number of current impedance coefficients, voltage impedance coefficients and resistance impedance coefficients collected is counted, and each impedance coefficient collected for the first time in the time period is used as a basis, and the coefficient collected for the second time in the time period is used as a benchmark for setting; Based on the admittance coefficient of the same time period, in different distinguished sections, the distinguished sections are divided into [▽1, ▽2, ..., ▽ n ], where n represents the nth road section, and is set based on the admittance coefficients collected for the ▽1 section and the admittance coefficient of the section after the change to the admittance coefficient of the ▽2 section.

7. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 1, characterized in that: The updated data set is divided into a training set, a test set and a validation set. In the test set, when analyzing the impact characteristics of different factors on the operation of the preset power grid, a test period is preset, wherein each period is 3 to 5 minutes apart. In the interval, data changes including current, voltage and resistance are collected, and the impact changes are obtained based on the data changes. When the data changes of the preset power grid in the future period show an increasing trend within the interval period, it is determined that the operating state of the preset power grid is unstable. Otherwise, it is not determined.

8. The electromagnetic transient modeling method based on embedded direct current transmission according to claim 7, characterized in that: The influencing changes include changes in circuit load of a preset power grid, and the correlation characteristics between different load changes and power consumption, line short circuit, and line length are collected. At the same time, the sections distinguished according to the load changes are marked as stable change sections and unstable change sections. In the unstable change sections, the correlation rules between the load changes and various forming factors are obtained.

9. An electronic device, characterized in that: The method comprises a processor, an input interface, an output interface and a memory, wherein the processor, the input interface, the output interface and the memory are interconnected, wherein the memory is used to store a computer program, the computer program comprises program instructions, and the processor is configured to call the program instructions to execute the electromagnetic transient modeling method based on embedded direct current transmission according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the processor executes the electromagnetic transient modeling method based on embedded direct current transmission according to any one of claims 1 to 8.

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