Lightning protection performance evaluation method for weak current system of intelligent substation

Abstract

The invention discloses an intelligent substation weak current system lightning protection performance evaluation method, and belongs to the technical field of substations. Comprising the following steps; the method comprises the following steps: S1, data acquisition: collecting information of all weak current system equipment in a transformer substation, including equipment types, installation positions and connection modes, and then acquiring local lightning activity data; through multi-scene simulation, lightning events of different types and intensities can be simulated, the lightning protection performance of the system in various lightning scenes can be comprehensively evaluated, the lightning protection performance is not limited to a certain specific condition, meanwhile, the lightning impulse process can be realistically restored through multi-scene simulation, more real lightning protection performance evaluation is provided, and the lightning protection performance of the system is improved. And then, by comparing simulation results under different lightning scenes, weak links and potential risk points of the system under different lightning conditions can be found, and targeted improvement is carried out, so that the overall lightning protection performance of the weak current system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of substations, and more specifically to a method for evaluating the lightning protection performance of a weak current system of an intelligent substation. Background Art

[0002] A substation is a place in the power system that transforms voltage and current, receives electric energy, and distributes electric energy. The substation in a power plant is a step-up substation, which boosts the electric energy generated by the generator and feeds it into the high-voltage power grid.

[0003] At present, the lightning protection performance evaluation method for substation weak current system mainly analyzes the collected data through the model to obtain the lightning protection performance evaluation of the weak current system. However, the lightning intensity is diverse, and there are multiple scenarios of lightning events, and the model cannot simulate lightning events in multiple scenarios, which reduces the authenticity of the lightning protection performance evaluation and further reduces the overall lightning protection performance of the weak current system. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating the lightning protection performance of a weak current system of an intelligent substation to solve the problems raised in the above-mentioned background technology.

[0005] A method for evaluating the lightning protection performance of a weak current system of an intelligent substation, the method comprising the following steps:

[0006] S1. Data collection: Collect information on all weak current system equipment in the substation, including equipment type, installation location and connection method, and then obtain local lightning activity data, including the number of thunderstorm days, lightning current intensity and lightning frequency;

[0007] S2, Intelligent Model: Preprocess the collected data and extract features from the preprocessed data. Then, input the extracted features into the intelligent model for model training. The trained model is then evaluated using an independent test data set. The evaluation indicators may include accuracy, recall, and F1 value.

[0008] S3, Data Analysis: Conduct risk assessment on the assessment results, and then conduct lightning protection demand analysis based on the collected data and risk assessment results;

[0009] S4, scenario simulation and generation: Classify and summarize lightning scenarios and divide them into different types, and then simulate and generate different types of lightning scenarios through data simulation technology;

[0010] S5. Lightning protection measures design: Design the grounding grid based on the analysis results and scenario simulation results, and shield the core weak current equipment and lines to ensure that the equipment and grounding devices are connected at the same potential;

[0011] S6. On-site testing and verification: Test the grounding resistance as well as the performance and installation effect of the surge protector, and compare the test results with the simulation results to verify the accuracy of the simulation model and the reliability of the lightning protection measures. Then, combine the results of on-site investigation, simulation analysis and actual testing to form a complete evaluation report, and based on the evaluation results, put forward suggestions for further optimization and improvement of lightning protection measures.

[0012] Preferably, the S1 further comprises the following steps:

[0013] S1-1. Collect substation data: record the geographical coordinates of the substation, including latitude, longitude and altitude, and understand the total capacity and floor space of the substation, and then collect the substation operation data, including operation time, equipment load and failure rate;

[0014] S1-2. Collect historical data: Collect detailed records of lightning strikes in the substation history, including time, location, lightning strike intensity and damage caused, and then obtain fault records of weak current system equipment in the substation. At the same time, collect lightning protection measures implemented in the substation, including grounding system, shielding measures and installation of surge protectors;

[0015] S1-3. Site survey: Through field investigation and maps, understand the environmental information of the substation's topography and soil resistivity, and record the factors that affect the propagation of lightning current such as buildings, trees and power lines around the substation.

[0016] Preferably, the S2 further comprises the following steps:

[0017] S2-1. Data preprocessing: preprocess the collected data, including data cleaning, denoising and normalization operations, to ensure data quality and consistency. The purpose of preprocessing is to improve the accuracy and reliability of subsequent algorithms.

[0018] S2-2, Model training: Extract features from the processed data and build a model based on the extracted features. When the model is built, use the processed data to train the model until the model training is completed, and then use an independent test data set to evaluate the trained model.

[0019] The model is built using support vector machine, which is a supervised learning model for classification and regression analysis. Its core idea is to find an optimal hyperplane in the feature space to separate samples of different categories and maximize the distance from the closest sample points on both sides to the hyperplane:

[0020] In the binary classification problem, the decision function of the support vector machine can be expressed as:

[0021] f(x)=sign(w·x+b)

[0022] in:

[0023] f(x) is the decision function used to predict the category of sample x;

[0024] w is the normal vector (weight vector) of the hyperplane, which determines the direction of the hyperplane:

[0025] x is the feature vector of the sample;

[0026] b is the bias term (intercept), which determines the distance between the hyperplane and the origin;

[0027] Represents the dot product of vectors;

[0028] The sign function converts the result of the decision function into a category label, that is, when w·x+b>0, the predicted sample belongs to the positive class (+1), and when w·x+b<0, the predicted sample belongs to the negative class (-1);

[0029] In the support vector machine, the parameters w and b of the decision function are obtained through training data. The goal is to maximize the margin (i.e., the distance between the support vectors on both sides and the hyperplane) while minimizing the classification error.

[0030] If the data is linearly inseparable, a kernel function can be used to map the data into a high-dimensional space, so that the data can be linearly separable in the high-dimensional space. The decision function can be expressed as:

[0031] f(x)=sign(∑ N i＝1 a i y i K(x,x i )+b)

[0032] where α i is the Lagrange multiplier of the support vector machine, y i is the class label of sample x; K(x,x i) is the kernel function, used to calculate the relationship between sample x and x i Inner products in high-dimensional spaces.

[0033] Preferably, the S3 further comprises the following steps:

[0034] S3-1, Lightning density analysis: Based on the lightning density data in the assessment data, calculate the annual lightning strike probability in the area where the substation is located, then evaluate the sensitivity of the weak current system equipment to lightning strikes, and analyze the potential fault types and severity of the equipment after being struck by lightning. The sensitivity includes withstand voltage and surge resistance;

[0035] S3-2, Risk quantification: Based on the probability of lightning strikes and the vulnerability of equipment, a risk matrix is ​​constructed, and the risks are divided into different levels, such as high, medium, and low. Then, based on the matrix results, the risk level of each device and system is divided.

[0036] Preferably, the S3 further comprises the following steps:

[0037] S3-3. Loss assessment: Calculate the economic losses caused by equipment damage, including repair, replacement and downtime losses, and assess the safety hazards caused by lightning strikes, such as fires or other safety accidents caused by equipment failure;

[0038] S3-4. Lightning protection demand analysis: Based on the collected data, lightning density analysis, risk quantification and loss assessment results, determine the specific needs of the substation lightning protection system, including the specifications and quantity of lightning protection equipment, design requirements of the grounding system and lightning protection measures for communication lines.

[0039] Preferably, the S4 further comprises the following steps:

[0040] S4-1. Set boundary conditions: Use electromagnetic field simulation software to build a simulation model, and build an electrical model of the smart substation in the simulation software, including transformers, circuit breakers, grounding systems and communication equipment, and then set the boundary conditions of the simulation model, such as ground conductivity and resistance of the grounding system;

[0041] S4-2. Execute simulation: After setting the boundary conditions of the simulation model, set the initial operating state of the system and the initial lightning parameters, and then run the simulation program to simulate the impact of lightning on the substation system and record the changes in key parameters of voltage, current and magnetic field.

[0042] Preferably, the S4 further comprises the following steps:

[0043] S4-3, Multi-scenario simulation: Conduct multiple simulations for lightning events of different types and intensities to comprehensively evaluate the lightning protection performance of the system under various lightning scenarios, and then compare the simulation results under different lightning scenarios to identify the weak links and risk points of the system under different lightning conditions;

[0044] S4-4. Result analysis: The simulation results are processed and the response characteristics of the system under lightning impulse are analyzed from multiple dimensions. The simulation results are then displayed in the form of three-dimensional graphics to intuitively reflect the impact and propagation path of lightning impulses, as well as response characteristics such as voltage, overcurrent, and equipment damage.

[0045] Preferably, the S5 further comprises the following steps:

[0046] S5-1, Lightning protection design: Design the grounding grid based on the analysis results and scenario simulation results, then calculate the grounding resistance, and design the connection method between the lightning protection equipment and the grounding system to ensure good electrical connection and low impedance path;

[0047] S5-2. Implementation of lightning protection measures: Install lightning arresters and surge protectors in accordance with design requirements, and shield cables and equipment cabinets with shielding covers. Then, perform performance tests on the installed lightning protection equipment to ensure that it meets the technical requirements.

[0048] Compared with the prior art, the advantages of the present invention are:

[0049] (1) In the present invention, multi-scenario simulation can be used to simulate lightning events of different types and intensities, and the lightning protection performance of the system under various lightning scenarios can be comprehensively evaluated, rather than being limited to a specific situation. At the same time, multi-scenario simulation can realistically restore the lightning impact process and provide a more realistic lightning protection performance evaluation. Then, by comparing the simulation results under different lightning scenarios, the weak links and potential risk points of the system under different lightning conditions can be discovered, and targeted improvements can be made to improve the overall lightning protection performance of the weak current system.

[0050] (2) In the present invention, by setting boundary conditions and executing simulations, a real simulation environment can be created, thereby improving the accuracy and reliability of simulation results. By executing simulations, the system response under lightning strikes can be dynamically recorded, providing detailed data on changes in key parameters, thereby providing a solid foundation for comprehensively evaluating the lightning protection performance of the system. By recording the changes in multiple parameters, the impact of lightning on the system can be analyzed from multiple dimensions, thereby comprehensively evaluating the lightning protection capability of the system.

[0051] (3) In the present invention, by evaluating the sensitivity of weak current system equipment to lightning strikes, the equipment most susceptible to lightning strikes can be identified, providing a basis for lightning protection design. The risk matrix can intuitively display the risk levels of different equipment and systems, facilitating the identification and prioritization of high-risk areas. Then, through risk level classification, resource allocation can be optimized, more resources can be invested in high-risk equipment and areas, and the overall lightning protection safety can be improved. Finally, by evaluating economic losses, a cost-benefit analysis can be conducted to help decision makers balance lightning protection investment and expected losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the overall process of the present invention. DETAILED DESCRIPTION

[0053] Example: See Figure 1 ,A method for evaluating the lightning protection performance of the weak current system of an intelligent substation ...including the following steps;

[0054] S1. Data collection: Collect information on all weak current system equipment in the substation, including equipment type, installation location and connection method, and then obtain local lightning activity data, including the number of thunderstorm days, lightning current intensity and lightning frequency;

[0055] S2, Intelligent Model: Preprocess the collected data and extract features from the preprocessed data. Then, input the extracted features into the intelligent model for model training. The trained model is then evaluated using an independent test data set. The evaluation indicators may include accuracy, recall, and F1 value.

[0056] S3, Data Analysis: Conduct risk assessment on the assessment results, and then conduct lightning protection demand analysis based on the collected data and risk assessment results;

[0057] S4, scenario simulation and generation: Classify and summarize lightning scenarios and divide them into different types, and then simulate and generate different types of lightning scenarios through data simulation technology;

[0058] S5. Lightning protection measures design: Design the grounding grid based on the analysis results and scenario simulation results, and shield the core weak current equipment and lines to ensure that the equipment and grounding devices are connected at the same potential;

[0059] S6. On-site testing and verification: Test the grounding resistance as well as the performance and installation effect of the surge protector, and compare the test results with the simulation results to verify the accuracy of the simulation model and the reliability of the lightning protection measures. Then, combine the results of on-site investigation, simulation analysis and actual testing to form a complete evaluation report, and based on the evaluation results, put forward suggestions for further optimization and improvement of lightning protection measures.

[0060] S1 also includes the following steps:

[0061] S1-1. Collect substation data: record the geographical coordinates of the substation, including latitude, longitude and altitude, and understand the total capacity and floor space of the substation, and then collect the substation operation data, including operation time, equipment load and failure rate;

[0062] S1-2. Collect historical data: Collect detailed records of lightning strikes in the substation history, including time, location, lightning strike intensity and damage caused, and then obtain fault records of weak current system equipment in the substation. At the same time, collect lightning protection measures implemented in the substation, including grounding system, shielding measures and installation of surge protectors;

[0063] S1-3. Site survey: Through field investigation and maps, understand the environmental information of the substation's topography and soil resistivity, and record the factors that affect the propagation of lightning current such as buildings, trees and power lines around the substation.

[0064] S2 also includes the following steps:

[0065] S2-1. Data preprocessing: preprocess the collected data, including data cleaning, denoising and normalization operations, to ensure data quality and consistency. The purpose of preprocessing is to improve the accuracy and reliability of subsequent algorithms.

[0066] S2-2, Model training: Extract features from the processed data and build a model based on the extracted features. When the model is built, use the processed data to train the model until the model training is completed, and then use an independent test data set to evaluate the trained model.

[0067] S3 also includes the following steps:

[0068] S3-1, Lightning density analysis: Based on the lightning density data in the assessment data, calculate the annual lightning strike probability in the area where the substation is located, then evaluate the sensitivity of the weak current system equipment to lightning strikes, and analyze the potential fault types and severity of the equipment after being struck by lightning. The sensitivity includes withstand voltage and surge resistance;

[0069] S3-2, Risk quantification: Based on the probability of lightning strikes and the vulnerability of equipment, a risk matrix is ​​constructed, and the risks are divided into different levels, such as high, medium, and low. Then, based on the matrix results, the risk level of each device and system is divided.

[0070] S3 also includes the following steps:

[0071] S3-3. Loss assessment: Calculate the economic losses caused by equipment damage, including repair, replacement and downtime losses, and assess the safety hazards caused by lightning strikes, such as fires or other safety accidents caused by equipment failure;

[0072] S3-4. Lightning protection demand analysis: Based on the collected data, lightning density analysis, risk quantification and loss assessment results, determine the specific needs of the substation lightning protection system, including the specifications and quantity of lightning protection equipment, design requirements of the grounding system and lightning protection measures for communication lines.

[0073] Specifically, by evaluating the sensitivity of weak current system equipment to lightning strikes, the equipment most vulnerable to lightning strikes can be identified, providing a basis for lightning protection design. The risk matrix can intuitively display the risk levels of different equipment and systems, facilitating the identification and prioritization of high-risk areas. Then, through risk level classification, resource allocation can be optimized, more resources can be invested in high-risk equipment and areas, and overall lightning protection safety can be improved. Finally, by evaluating economic losses, cost-benefit analysis can be conducted to help decision makers balance lightning protection investment and expected losses.

[0074] S4 also includes the following steps:

[0075] S4-1. Set boundary conditions: Use electromagnetic field simulation software to build a simulation model, and build an electrical model of the smart substation in the simulation software, including transformers, circuit breakers, grounding systems and communication equipment, and then set the boundary conditions of the simulation model, such as ground conductivity and resistance of the grounding system;

[0076] S4-2. Execute simulation: After setting the boundary conditions of the simulation model, set the initial operating state of the system and the initial lightning parameters, and then run the simulation program to simulate the impact of lightning on the substation system and record the changes in key parameters of voltage, current and magnetic field.

[0077] Specifically, by setting boundary conditions and executing simulations, a real simulation environment can be created to improve the accuracy and reliability of simulation results. By executing simulations, the system response under lightning strikes can be dynamically recorded, and detailed key parameter change data can be provided, providing a solid foundation for comprehensively evaluating the lightning protection performance of the system. At the same time, by recording the changes in multiple parameters, the impact of lightning on the system can be analyzed from multiple dimensions to comprehensively evaluate the lightning protection capabilities of the system.

[0078] S4 also includes the following steps:

[0079] S4-3, Multi-scenario simulation: Conduct multiple simulations for lightning events of different types and intensities to comprehensively evaluate the lightning protection performance of the system under various lightning scenarios, and then compare the simulation results under different lightning scenarios to identify the weak links and risk points of the system under different lightning conditions;

[0080] S4-4. Result analysis: The simulation results are processed and the response characteristics of the system under lightning impulse are analyzed from multiple dimensions. The simulation results are then displayed in the form of three-dimensional graphics to intuitively reflect the impact and propagation path of lightning impulses, as well as response characteristics such as voltage, overcurrent, and equipment damage.

[0081] Specifically, multi-scenario simulation can be used to simulate lightning events of different types and intensities, and the lightning protection performance of the system in various lightning scenarios can be comprehensively evaluated, not just limited to a specific situation. At the same time, multi-scenario simulation can realistically restore the lightning impact process and provide a more realistic lightning protection performance evaluation. Then, by comparing the simulation results under different lightning scenarios, the weak links and potential risk points of the system under different lightning conditions can be discovered, and targeted improvements can be made to improve the overall lightning protection performance of the weak current system.

[0082] S5 also includes the following steps:

[0083] S5-1, Lightning protection design: Design the grounding grid based on the analysis results and scenario simulation results, then calculate the grounding resistance, and design the connection method between the lightning protection equipment and the grounding system to ensure good electrical connection and low impedance path;

[0084] S5-2. Implementation of lightning protection measures: Install lightning arresters and surge protectors in accordance with design requirements, and shield cables and equipment cabinets with shielding covers. Then, perform performance tests on the installed lightning protection equipment to ensure that it meets the technical requirements.

[0085] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for evaluating the lightning protection performance of a weak current system of an intelligent substation, characterized in that: The method for evaluating the lightning protection performance of the weak current system of a smart substation comprises the following steps: S1. Data collection: Collect information on all weak current system equipment in the substation, including equipment type, installation location and connection method, and then obtain local lightning activity data; S2, Intelligent Model: Preprocess the collected data and extract features from the preprocessed data. The extracted features are then input into the intelligent model for model training. The trained model is then evaluated using an independent test data set. S3, Data Analysis: Conduct risk assessment on the assessment results, and then conduct lightning protection demand analysis based on the collected data and risk assessment results; S4, scenario simulation and generation: Classify and summarize lightning scenarios and divide them into different types, and then simulate and generate different types of lightning scenarios through data simulation technology; S5. Lightning protection measures design: Design the grounding grid based on the analysis results and scenario simulation results, and shield the core weak current equipment and lines to ensure that the equipment and grounding devices are connected at the same potential; S6. On-site testing and verification: Test the grounding resistance as well as the performance and installation effect of the surge protector, and compare the test results with the simulation results to verify the accuracy of the simulation model and the reliability of the lightning protection measures. Then, combine the results of on-site investigation, simulation analysis and actual testing to form a complete evaluation report, and based on the evaluation results, put forward suggestions for further optimization and improvement of lightning protection measures.

2. According to claim 1, a method for evaluating lightning protection performance of a weak current system of an intelligent substation is characterized in that: The S1 further comprises the following steps: S1-1. Collect substation data: record the geographical coordinates of the substation, including latitude, longitude and altitude, and understand the total capacity and floor space of the substation, and then collect the substation operation data, including operation time, equipment load and failure rate; S1-2. Collect historical data: Collect detailed records of lightning strikes in the substation history, including time, location, lightning strike intensity and damage caused, and then obtain fault records of weak current system equipment in the substation. At the same time, collect lightning protection measures implemented in the substation, including grounding system, shielding measures and installation of surge protectors; S1-3. Site survey: Through field investigation and maps, understand the environmental information of the substation's topography and soil resistivity, and record the factors that affect the propagation of lightning current such as buildings, trees and power lines around the substation.

3. The method for evaluating lightning protection performance of a weak current system of a smart substation according to claim 1 is characterized in that: The S2 further comprises the following steps: S2-1. Data preprocessing: preprocess the collected data, including data cleaning, denoising and normalization operations; S2-2, Model training: Extract features from the processed data and build a model based on the extracted features. When the model is built, use the processed data to train the model until the model training is completed, and then use an independent test data set to evaluate the trained model.

4. The method for evaluating lightning protection performance of a weak current system of a smart substation according to claim 1 is characterized in that: The S3 further comprises the following steps: S3-1. Lightning density analysis: Based on the lightning density data in the assessment data, calculate the annual lightning strike probability in the area where the substation is located, then evaluate the sensitivity of the weak current system equipment to lightning strikes, and analyze the potential fault types and severity of the equipment after being struck by lightning; S3-2, Risk quantification: Based on the probability of lightning strikes and the vulnerability of equipment, a risk matrix is ​​constructed, and the risks are divided into different levels, such as high, medium, and low. Then, based on the matrix results, the risk level of each device and system is divided.

5. A method for evaluating lightning protection performance of a weak current system of a smart substation according to claim 4, characterized in that: The S3 further comprises the following steps: S3-3. Loss assessment: Calculate the economic losses caused by equipment damage, including repair, replacement and downtime losses, and assess the safety hazards caused by lightning strikes; S3-4. Lightning protection demand analysis: Based on the collected data, lightning density analysis, risk quantification and loss assessment results, determine the specific needs of the substation lightning protection system, including the specifications and quantity of lightning protection equipment, design requirements of the grounding system and lightning protection measures for communication lines.

6. The method for evaluating lightning protection performance of a weak current system of a smart substation according to claim 1 is characterized in that: The S4 further comprises the following steps: S4-1. Set boundary conditions: Use electromagnetic field simulation software to build a simulation model, and build an electrical model of the smart substation in the simulation software, including transformers, circuit breakers, grounding systems and communication equipment, and then set the boundary conditions of the simulation model; S4-2. Execute simulation: After setting the boundary conditions of the simulation model, set the initial operating state of the system and the initial parameters of lightning, and then run the simulation program to simulate the impact process of lightning on the substation system.

7. A method for evaluating lightning protection performance of a weak current system of a smart substation according to claim 6, characterized in that: The S4 further comprises the following steps: S4-3, Multi-scenario simulation: Conduct multiple simulations for lightning events of different types and intensities to comprehensively evaluate the lightning protection performance of the system under various lightning scenarios, and then compare the simulation results under different lightning scenarios to identify the weak links and risk points of the system under different lightning conditions; S4-4. Result analysis: The simulation results are processed and the response characteristics of the system under lightning impulse are analyzed from multiple dimensions. The simulation results are then displayed in the form of three-dimensional graphics to intuitively reflect the impact and propagation path of lightning impulse.

8. The method for evaluating lightning protection performance of a weak current system of a smart substation according to claim 1, characterized in that: The S5 further comprises the following steps: S5-1, Lightning protection design: Design the grounding grid based on the analysis results and scenario simulation results, then calculate the grounding resistance, and design the connection method between the lightning protection equipment and the grounding system; S5-2. Implementation of lightning protection measures: Install lightning arresters and surge protectors in accordance with design requirements, install shielding covers on cables and equipment cabinets, and then perform performance tests on the installed lightning protection equipment.

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