Flexible direct current simulation model parameter correction method and system combined with fault recording data

Abstract

The invention discloses a flexible direct current simulation model parameter correction method and system combined with fault recording data, belongs to the technical field of power system analogue simulation, and solves the problems that errors exist between a fault calculation result and an actual measurement value, a traditional method does not fully utilize the fault recording data, and the fault recording data cannot be fully utilized in the prior art. Therefore, related parameters of the fault simulation model of the flexible DC system cannot be effectively corrected. Building a simulation model; selecting a typical fault based on the fault recording file, calling corresponding fault recording data, and processing the fault recording data; based on the simulation model, performing fault analysis on the typical fault to obtain analysis data; and performing comparative analysis on the processed fault recording data and analysis data, judging whether an analysis result meets requirements or not, if so, outputting the analysis data, and if not, adjusting parameters of the simulation model, and performing fault analysis again. The method is used for realizing accurate and effective simulation model data correction.

Description

Technical Field

[0001] This invention relates to the field of power system simulation technology, specifically to a method and system for correcting parameters of a flexible DC simulation model that incorporates fault recording data. Background Technology

[0002] Flexible DC transmission systems possess a complex physical nature characterized by high nonlinearity and multi-timescale variations. Their fault transient behavior stems from the nonlinear switching characteristics of power electronic devices, exhibiting multi-timescale dynamic response coupling ranging from microseconds to minutes. The transient development process of electrical quantities after a fault is complex, influenced by numerous factors, and cannot be directly described by simple formulas. Using electromagnetic transient simulation software is a fundamental method for quantitative analysis of faults in flexible DC transmission systems. However, in various fault simulation calculations, differing calculation standards, different models used by different software, and varying approximation conditions lead to varying degrees of error between the fault calculation results of different simulation software and the actual measured values ​​in the power grid.

[0003] Chinese patent document CN201010581568.9 discloses "A Correction Method for Simulation Trajectory of Dynamic Process of Power Grid Frequency," which proposes using the actual frequency trajectory of the system under fault conditions as a reference, adjusting the governor parameters within a feasible range to make the simulated trajectory approximate the actual frequency trajectory, and evaluating the degree of approximation by establishing an error evaluation model, and adjusting relevant parameters through tabu search to achieve effective correction of the frequency simulation trajectory. Chinese patent document CN201510733362.6 discloses "A Simulation Playback Method for Fault Recording in High Voltage Direct Current Transmission Systems," which proposes outputting voltage waveform data before and after a fault to a high voltage direct current transmission system simulation model, and switching between the amplitude and phase data with an ideal voltage source to achieve waveform playback. Chinese patent document CN202411371771.1 discloses a "method for modeling photovoltaic power stations for relay protection using fault recording data." This method involves centralized processing of fault recording system data in substations, aligning the recorded data, and using least squares fitting to calculate the fault short-circuit current and voltage, thus deriving a short-circuit calculation model for the new energy power station. However, this technical solution does not fully utilize fault recording data and cannot effectively correct the relevant parameters of the fault simulation model for flexible DC systems.

[0004] Chinese patent document CN201410524183.7 discloses "an error analysis method for short-circuit current simulation calculation," which compares the difference between actual fault waveform data and system simulation data to determine the short-circuit current calculation error of the simulation system and corrects the simulation data. However, this patent does not explain the relationship between the fault waveform data used and the simulation calculation module, nor does it explain the specific method for error correction.

[0005] In summary, existing technologies suffer from errors between fault calculation results and actual measured values, and traditional methods do not fully utilize fault waveform data, resulting in the inability to effectively correct relevant parameters of the fault simulation model of flexible DC systems. Summary of the Invention

[0006] This invention solves the technical problem that existing technologies have errors between fault calculation results and actual measurement values, and traditional methods do not make full use of fault recording data, thus making it impossible to effectively correct the relevant parameters of the fault simulation model of flexible DC systems.

[0007] The present invention provides a method for correcting parameters of a flexible DC simulation model based on fault recording data, comprising the following steps: Step 1: Build a simulation model of the flexible DC transmission system; Step 2: Select typical faults based on the fault recording files of the flexible DC transmission system, retrieve the fault recording data corresponding to the typical faults, and process the fault recording data. Step 3: Based on the simulation model, perform fault analysis on the typical faults to obtain analysis data; Step 4: Compare and analyze the fault waveform data processed in Step 2 with the analysis data to determine whether the analysis results meet the requirements. If yes, output the analysis data; otherwise, adjust the parameters of the simulation model based on the analysis results and repeat Step 3 and Step 4.

[0008] Furthermore, in one embodiment of the present invention, the step 1 of building a simulation model of a flexible DC transmission system includes the following steps: Step 11: Based on the electrical main wiring diagram of the flexible DC transmission system, determine the parameters of each electrical device in the fault branch and obtain the equivalent parameters of the corresponding bay equipment; Step 12: Based on the equivalent parameters of the interval equipment, determine the equivalent circuit of each electrical device according to the connection sequence and position of each electrical device in the fault branch of the electrical main wiring diagram; Step 13: Based on the equivalent circuits of each electrical device, build a simulation model.

[0009] Furthermore, in one embodiment of the present invention, the typical faults in step 2 include converter side faults, DC side faults, and AC side faults.

[0010] Furthermore, in one embodiment of the present invention, the processing of the fault recording data in step 2 specifically includes: Each electrical quantity sampling point of the retrieved fault waveform data is labeled with a time tag, and the time tags are aligned.

[0011] Furthermore, in one embodiment of the present invention, the data analyzed in step 3 is the electrical quantity in the fault waveform data corresponding to a typical fault.

[0012] Furthermore, in one embodiment of the present invention, the comparative analysis in step 4 includes the following steps: Step 41: Calculate the degree of similarity between the processed fault waveform data and the analysis data at each same time point; Step 42: Calculate the proportion of the size of the fault waveform data at each time point to the total size of the fault waveform data at all time points, and use it as the weight of the corresponding time point. Step 43: Based on the proximity described in Step 41 and the weights described in Step 42, obtain the weighted similarity comprehensive index. ; Step 44: Extract the electrical quantities used for protection settings from the fault recording data and simulation data, and obtain the similarity of the electrical quantities based on the electrical quantities used for protection settings. ; The Including similarity of overcurrent values ​​in bridge arms DC low voltage value similarity Similarity of traveling wave protection action quantity Similarity to AC overcurrent value ; Step 45, will and As part of the analysis, determine whether the results meet the requirements.

[0013] Furthermore, in one embodiment of the present invention, the determination of whether the analysis result meets the requirements specifically includes: like <90%, or ≥90% and If it is less than 95%, it does not meet the requirements. ≥90% and If it is ≥95%, then it meets the requirements.

[0014] Furthermore, in one embodiment of the present invention, adjusting the parameters of the simulation model based on the analysis results in step 4 specifically involves: like If the value is less than 95%, then adjust the equivalent parameters of the converter measuring equipment in the simulation model. like <95% or If the value is less than 95%, then adjust the equivalent parameters of the DC-side equipment in the simulation model. like If the value is less than 95%, then adjust the equivalent parameters of the AC side equipment in the simulation model.

[0015] Furthermore, in one embodiment of the present invention, the sampling frequency of the fault recording data is 10kHz.

[0016] The flexible DC simulation model parameter correction system combining fault recording data, as described in this invention, includes the following modules: Module 1: Building a simulation model of a flexible DC transmission system; Module 2 selects typical faults from the fault recording files of the flexible DC transmission system, retrieves the fault recording data corresponding to the typical faults, and processes the fault recording data. Module 3, based on the simulation model, performs fault analysis on the typical faults to obtain analysis data; Module 4 compares and analyzes the fault waveform data processed by Module 2 with the analysis data to determine whether the analysis results meet the requirements. If yes, the analysis data is output; otherwise, the parameters of the simulation model are adjusted based on the analysis results, and Modules 3 and 4 are executed again.

[0017] This invention solves the technical problem that existing technologies have errors between fault calculation results and actual measured values, and that traditional methods do not fully utilize fault waveform data, thus making it impossible to effectively correct relevant parameters of the fault simulation model of flexible DC systems. Specific beneficial effects include: This invention proposes a method for correcting parameters of a flexible DC simulation model by combining fault recording data. By extracting fault recording data and data from the flexible DC model simulation, and confirming the fault type and characteristics through data comparison, the relevant parameters of the fault simulation model of the flexible DC system can be effectively corrected using actual fault recording data. This achieves the purpose of correcting the simulation model data, thereby improving the reliability and accuracy of the simulation model and providing reliable data support for the setting configuration of relay protection devices. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of the parameter correction method for the flexible DC simulation model combining fault recording data as described in Implementation Method 1; Figure 2 This is a flowchart illustrating the comparison and analysis of fault waveform data and simulation model data as described in Implementation Method Six. Detailed Implementation

[0019] Various embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] Implementation Method 1: A method for correcting parameters of a flexible DC simulation model based on fault recording data, comprising the following steps: Step 1: Build a simulation model of the flexible DC transmission system; Step 2: Select typical faults based on the fault recording files of the flexible DC transmission system, retrieve the fault recording data corresponding to the typical faults, and process the fault recording data. Step 3: Based on the simulation model, perform fault analysis on the typical faults to obtain analysis data; Step 4: Compare and analyze the fault waveform data processed in Step 2 with the analysis data to determine whether the analysis results meet the requirements. If yes, output the analysis data; otherwise, adjust the parameters of the simulation model based on the analysis results and repeat Step 3 and Step 4.

[0021] Due to inconsistent calculation standards, different calculation software adopts different models when performing various fault simulation calculations, and different approximation conditions are selected during the calculation. These factors lead to errors between the fault calculation results and the actual measured values ​​in the power grid. Traditional methods do not make full use of fault recording data, resulting in the inability to effectively correct the relevant parameters of the fault simulation model of the flexible DC system.

[0022] To address the aforementioned problems, this embodiment provides a novel method for correcting parameters in a flexible straight-line simulation model, such as... Figure 1 As shown, by extracting fault waveform data and data from the flexible DC model simulation, and by confirming the fault type and characteristics and comparing the data, the actual fault waveform data can be effectively used to effectively correct the relevant parameters of the fault simulation model of the flexible DC system. This achieves the purpose of correcting the simulation model data, thereby improving the reliability and accuracy of the simulation model and providing reliable data support for the setting configuration of relay protection devices.

[0023] Implementation Method Two: This implementation method further defines the parameter correction method for a flexible DC transmission simulation model combining fault recording data described in Implementation Method One. Step 1, building the simulation model of the flexible DC transmission system, includes the following steps: Step 11: Based on the electrical main wiring diagram of the flexible DC transmission system, determine the parameters of each electrical device in the fault branch and obtain the equivalent parameters of the corresponding bay equipment; Step 12: Based on the equivalent parameters of the interval equipment, determine the equivalent circuit of each electrical device according to the connection sequence and position of each electrical device in the fault branch of the electrical main wiring diagram; Step 13: Based on the equivalent circuits of each electrical device, build a simulation model.

[0024] In this embodiment, a simulation model is built by determining the flexible DC transmission system, the connected electrical equipment and electrical parameters according to the main electrical wiring diagram, the equivalent circuit of each electrical equipment, and the determination of the equivalent circuit of each electrical equipment.

[0025] This implementation method determines the equivalent parameters of the equipment in the faulty branch based on the parameters of each electrical device in the main electrical wiring diagram, including the following parameters: 1) Equivalent parameters of converter equipment, including equivalent impedance parameters of converter valves, including the on-resistance (Ω) and off-resistance (Ω) of IGBT modules; The parameters of the converter transformer include rated capacity (MVA), short-circuit impedance percentage (%), winding resistance (Ω), leakage reactance (Ω), turns ratio, excitation branch resistance (Ω), and excitation branch inductance (H). 2) Equivalent parameters of DC-side equipment, including DC line parameters such as resistance per unit length (Ω / km) and inductance per unit length (H / km); Smoothing reactor parameters, including obtaining inductance (H) and resistance (Ω); DC filter parameters, including resistance (Ω), inductance (H), and capacitance (F); 3) Equivalent parameters of AC side equipment, including AC system parameters including equivalent resistance (Ω) and equivalent reactance (Ω); AC filter parameters, including resistance (Ω), inductance (H), and capacitance (F); Parallel capacitor parameters include capacitance (F) and equivalent resistance (Ω).

[0026] Based on the connection sequence and location of each electrical device in the faulty branch of the main electrical wiring diagram, calculate the equivalent circuit of each electrical device.

[0027] Implementation Method 3: This implementation method further defines the parameter correction method for a flexible DC simulation model that combines fault recording data as described in Implementation Method 1. The typical faults in step 2 include converter faults, DC side faults, and AC side faults.

[0028] In this embodiment, the time period during which the fault occurs is the time period from the occurrence of the fault to the end of the fault, and the sampling frequency of the fault recording data is 10kHz.

[0029] Implementation Method Four: This implementation method further defines the parameter correction method for a flexible DC simulation model combining fault recording data described in Implementation Method One. Specifically, step 2 involves processing the fault recording data as follows: Each electrical quantity sampling point of the retrieved fault waveform data is labeled with a time tag, and the time tags are aligned.

[0030] In this embodiment, fault recording files are obtained from the fault recording analysis system of each substation in the flexible DC transmission system, typical faults are selected, and fault recording data recorded by each substation in the system during the time period of the fault occurrence are retrieved and processed.

[0031] Implementation Method 5: This implementation method further defines the parameter correction method for a flexible DC simulation model that combines fault waveform data as described in Implementation Method 1. In step 3, the analyzed data are electrical quantities in the fault waveform data corresponding to typical faults.

[0032] In this embodiment, setting typical faults in the simulation model means simulating the selected typical faults in the simulation model. This implementation method performs fault analysis and calculation through a simulation model and obtains relevant data. It calculates the values ​​of electrical quantities corresponding to the fault recording data, and the sampling frequency is not less than 10kHz.

[0033] Implementation Method Six: This implementation method further defines the parameter correction method for a flexible DC simulation model combining fault recording data described in Implementation Method One. The comparative analysis in step 4 includes the following steps: Step 41: Calculate the degree of similarity between the processed fault waveform data and the analysis data at each same time point; Step 42: Calculate the proportion of the size of the fault waveform data at each time point to the total size of the fault waveform data at all time points, and use it as the weight of the corresponding time point. Step 43: Based on the proximity described in Step 41 and the weights described in Step 42, obtain the weighted similarity comprehensive index. ; Step 44: Extract the electrical quantities used for protection settings from the fault recording data and simulation data, and obtain the similarity of the electrical quantities based on the electrical quantities used for protection settings. ; The Including similarity of overcurrent values ​​in bridge arms DC low voltage value similarity Similarity of traveling wave protection action quantity Similarity to AC overcurrent value ; Step 45, will and As part of the analysis, determine whether the results meet the requirements.

[0034] The judgment and analysis results are as follows: like <90%, or ≥90% and If it is less than 95%, it does not meet the requirements. ≥90% and If it is ≥95%, then it meets the requirements.

[0035] like Figure 2 As shown, this implementation method retrieves fault waveform data and simulation data for each identical time point. Calculate fault recording data With simulation data proximity between The calculation formula is: ; Calculate the proportion of the fault waveform data at each time point to the total size of the fault waveform data at all time points. This is used as the weight for that time point. The calculation formula is: ; Where N is the Nth time point.

[0036] The weighted similarity index is obtained by multiplying the proximity at each time point by its weight and then summing the results. : ; This implementation extracts electrical quantities used for protection settings from fault recording data and simulation data, including: a. Calculate the similarity of overcurrent values ​​for the bridge arm protection current on the converter side: ; and These represent the maximum bridge arm current values ​​in the fault recording data and the simulation data, respectively.

[0037] b. For DC side protection voltage, calculate the similarity of DC undervoltage values: ; and These are the lowest DC line voltage values ​​from the fault recording data and the simulation data, respectively.

[0038] Calculate the similarity of traveling wave protection action quantities: ; and These represent the maximum voltage change rate in the fault recording data and the simulation data, respectively.

[0039] c. AC side protection current, calculate the similarity of AC overcurrent values: ; and These represent the maximum AC incoming current values ​​of the converter transformer in the fault recording data and the simulation data, respectively.

[0040] according to Value and Value, of which Values ​​include , , and Perform logical judgments: like Less than 90%, or Greater than or equal to 90% and If the deviation is less than 95%, it indicates that the electrical quantities extracted from the fault recording data and simulation data for use as protection settings do not meet the requirements, and the parameters of the simulation model should be adjusted.

[0041] like Greater than or equal to 90% and If the deviation is greater than or equal to 95%, it means that the electrical quantity deviation extracted from the fault recording data and simulation data for use as protection settings meets the requirements, and the correction process ends.

[0042] Implementation Method Seven: This implementation method further defines the parameter correction method for a flexible DC simulation model combining fault recording data described in Implementation Method One. Specifically, step 4, adjusting the simulation model parameters based on the analysis results, involves: like If the value is less than 95%, then adjust the equivalent parameters of the converter measuring equipment in the simulation model. like <95% or If the value is less than 95%, then adjust the equivalent parameters of the DC-side equipment in the simulation model. like If the value is less than 95%, then adjust the equivalent parameters of the AC side equipment in the simulation model.

[0043] In this embodiment, if <95% indicates that the AC side amplitude matching degree is not up to standard.

[0044] Implementation Method Eight: The flexible DC simulation model parameter correction system combining fault recording data described in this implementation method includes the following modules: Module 1: Building a simulation model of a flexible DC transmission system; Module 2 selects typical faults from the fault recording files of the flexible DC transmission system, retrieves the fault recording data corresponding to the typical faults, and processes the fault recording data. Module 3, based on the simulation model, performs fault analysis on the typical faults to obtain analysis data; Module 4 compares and analyzes the fault waveform data processed by Module 2 with the analysis data to determine whether the analysis results meet the requirements. If yes, the analysis data is output; otherwise, the parameters of the simulation model are adjusted based on the analysis results, and Modules 3 and 4 are executed again.

[0045] The above provides a detailed description of the method and system for correcting parameters of a flexible DC simulation model combining fault recording data proposed in this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for correcting parameters in a flexible DC simulation model based on fault recording data, characterized in that, Includes the following steps: Step 1: Build a simulation model of the flexible DC transmission system; Step 2: Select typical faults based on the fault recording files of the flexible DC transmission system, retrieve the fault recording data corresponding to the typical faults, and process the fault recording data. Step 3: Based on the simulation model, perform fault analysis on the typical faults to obtain analysis data; Step 4: Compare and analyze the fault waveform data processed in Step 2 with the analysis data to determine whether the analysis results meet the requirements. If yes, output the analysis data; otherwise, adjust the parameters of the simulation model based on the analysis results and repeat Step 3 and Step 4.

2. The method for correcting parameters of a flexible DC simulation model combining fault recording data as described in claim 1, characterized in that, The simulation model of the flexible DC transmission system built in step 1 includes the following steps: Step 11: Based on the electrical main wiring diagram of the flexible DC transmission system, determine the parameters of each electrical device in the fault branch and obtain the equivalent parameters of the corresponding bay equipment; Step 12: Based on the equivalent parameters of the interval equipment, determine the equivalent circuit of each electrical device according to the connection sequence and position of each electrical device in the fault branch of the electrical main wiring diagram; Step 13: Based on the equivalent circuits of each electrical device, build a simulation model.

3. The method for correcting parameters of a flexible DC simulation model combining fault recording data as described in claim 1, characterized in that, Typical faults in step 2 include converter side faults, DC side faults, and AC side faults.

4. The method for correcting parameters of a flexible DC simulation model combining fault recording data according to claim 1, characterized in that, Step 2 involves processing the fault recording data, specifically as follows: Each electrical quantity sampling point of the retrieved fault waveform data is labeled with a time tag, and the time tags are aligned.

5. The method for correcting parameters of a flexible DC simulation model combining fault recording data according to claim 1, characterized in that, The data analyzed in step 3 are the electrical quantities in the fault waveform data corresponding to typical faults.

6. The method for correcting parameters of a flexible DC simulation model combining fault recording data according to claim 1, characterized in that, The comparative analysis in step 4 includes the following steps: Step 41: Calculate the degree of similarity between the processed fault waveform data and the analysis data at each same time point; Step 42: Calculate the proportion of the size of the fault waveform data at each time point to the total size of the fault waveform data at all time points, and use it as the weight of the corresponding time point. Step 43: Based on the proximity described in Step 41 and the weights described in Step 42, obtain the weighted similarity comprehensive index. ; Step 44: Extract the electrical quantities used for protection settings from the fault recording data and simulation data, and obtain the similarity of the electrical quantities based on the electrical quantities used for protection settings. ; The Including similarity of overcurrent values ​​in bridge arms DC low voltage value similarity Similarity of traveling wave protection action quantity Similarity to AC overcurrent value ; Step 45, will and As part of the analysis, determine whether the results meet the requirements.

7. The method for correcting parameters of a flexible DC simulation model combining fault recording data according to claim 6, characterized in that, The judgment and analysis results are as follows: like <90%, or ≥90% and If it is less than 95%, it does not meet the requirements. ≥90% and If it is ≥95%, then it meets the requirements.

8. The method for correcting parameters of a flexible DC simulation model combining fault recording data according to claim 1, characterized in that, In step 4, adjusting the parameters of the simulation model based on the analysis results specifically involves: like If the value is less than 95%, then adjust the equivalent parameters of the converter measuring equipment in the simulation model. like <95% or If the value is less than 95%, then adjust the equivalent parameters of the DC-side equipment in the simulation model. like If the value is less than 95%, then adjust the equivalent parameters of the AC side equipment in the simulation model.

9. The method for correcting parameters of a flexible DC simulation model combining fault recording data according to claim 5, characterized in that, The fault recording data is sampled at a frequency of 10kHz.

10. A parameter correction system for a flexible DC simulation model combining fault recording data, characterized in that, Includes the following modules: Module 1: Building a simulation model of a flexible DC transmission system; Module 2 selects typical faults from the fault recording files of the flexible DC transmission system, retrieves the fault recording data corresponding to the typical faults, and processes the fault recording data. Module 3, based on the simulation model, performs fault analysis on the typical faults to obtain analysis data; Module 4 compares and analyzes the fault waveform data processed by Module 2 with the analysis data to determine whether the analysis results meet the requirements. If yes, the analysis data is output; otherwise, the parameters of the simulation model are adjusted based on the analysis results, and Modules 3 and 4 are executed again.

Images