Method and system for guiding resistance reduction transformation of grounding grid

Abstract

The invention discloses a method and a system for guiding resistance reduction transformation of a grounding grid, and relates to the technical field of power system grounding. Judging whether the actual grounding impedance value meets the design requirement or not; if the actual grounding impedance value does not meet the design requirement, obtaining the maximum short-circuit current of the system, and calculating a ground potential rise value when the grounding grid has a short-circuit fault; evaluating whether the ground potential rise value meets a standard requirement or not, and obtaining environment information of an area where the grounding grid is located; constructing a grounding grid transformation urgency evaluation model based on the environment information, evaluating the grounding grid transformation urgency through the grounding grid transformation urgency evaluation model, and outputting a transformation urgency level; and aiming at different transformation urgency levels, taking corresponding differential transformation measures to complete resistance reduction transformation of the grounding grid. Different transformation measures are taken according to different transformation urgency levels, so that rapid transformation under emergency conditions is ensured, preventive maintenance under general conditions is also considered, and the safe and stable operation requirements of the power system are better met.

Description

Technical Field

[0001] The invention relates to the technical field of power system grounding, and in particular to a method and system for guiding grounding network resistance reduction transformation. Background Art

[0002] The power system grounding grid is an important infrastructure to ensure the safe and reliable operation of the power system. The main functions of the grounding grid include protecting power equipment and personnel from lightning and dangerous voltages during operation, ensuring that the system can quickly cut off the fault current when a ground fault occurs, and maintaining the safety and stability of the system. Reasonable grounding design and good grounding performance are prerequisites for the safe operation of the power system.

[0003] However, over time, the performance of the grounding grid may gradually decline. When the grounding impedance value exceeds the design and regulatory requirements, it may cause the ground potential of the grounding grid to rise too high, the contact potential difference and the step potential difference to exceed the safety limit, and other problems, which in turn affect the stable operation of electrical equipment and threaten the personal safety of operators. In the face of this situation, whether it is necessary to carry out grounding grid resistance reduction transformation and what specific transformation measures should be taken have always been difficult problems faced by the power industry. Summary of the invention

[0004] In view of the fact that existing grounding grid transformation measures often lack systematicness and pertinence, and are difficult to effectively guide the transformation practice of actual projects, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to guide the implementation of grounding grid transformation through a systematic method to meet the requirements of safe and stable operation of the power system.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In the first aspect, an embodiment of the present invention provides a method for guiding the resistance reduction transformation of a grounding grid, which includes obtaining the grounding impedance test value and the grounding impedance design value of the grounding grid to be transformed, and calculating the actual value of the grounding impedance. The actual value of the grounding impedance is compared with the design value of the grounding impedance to determine whether the actual value of the grounding impedance meets the design requirements; if the actual value of the grounding impedance does not meet the design requirements, the maximum short-circuit current of the system is obtained, and the ground potential rise during the short-circuit fault of the grounding grid is calculated; whether the ground potential rise meets the standard requirements is evaluated, and the environmental information of the area where the grounding grid is located is obtained; a grounding grid transformation urgency assessment model is constructed based on the environmental information, and the urgency of the grounding grid transformation is evaluated through the grounding grid transformation urgency assessment model, and the transformation urgency level is output; for different transformation urgency levels, corresponding differentiated transformation measures are taken to complete the grounding grid resistance reduction transformation.

[0008] As a preferred solution of the method for guiding the grounding grid resistance reduction transformation of the present invention, the calculation formula of the actual value of the grounding impedance is as follows:

[0009]

[0010] Among them, R2 is the actual value of grounding impedance, R0 is the design value of grounding impedance, and k is the test value of shunt coefficient.

[0011] As a preferred solution of the method for guiding the grounding grid resistance reduction transformation of the present invention, wherein: evaluating whether the ground potential rise meets the standard requirements includes setting a standard limit value of the maximum ground potential rise value; evaluating the maximum ground potential rise value U p Whether it exceeds the standard limit; if U p If the standard limit is not exceeded, no grounding grid modification is required; if U p If the standard limit is exceeded, the environmental information of the area where the grounding grid is located is obtained, combined with the maximum ground potential rise value U p The technical factors that lead to the excessive rise in maximum ground potential are analyzed based on the environmental information; the environmental information includes lightning risk level, surrounding satellite map information and soil structure information of the site.

[0012] As a preferred solution of the method for guiding the resistance reduction transformation of the grounding grid described in the present invention, the process of confirming the lightning risk level is as follows: obtaining lightning monitoring data of the area where the grounding grid is located, the lightning monitoring data including lightning ground flash density, lightning strike frequency, and lightning intensity; using a deep learning algorithm to analyze the lightning monitoring data to identify the characteristics of lightning activity in the area where the grounding grid is located; designing quantitative indicators based on the characteristics of lightning activity, the quantitative indicators including lightning occurrence frequency index, lightning concentration index, and lightning intensity index; judging the lightning risk level of the area where the grounding grid is located by analyzing the quantitative indicators, including: if at least two of the three quantitative indicators are in a high-risk interval, then the area where the grounding grid is located is determined to be a high-risk area; if two of the three quantitative indicators are in a medium-risk interval, then the area where the grounding grid is located is determined to be a medium-risk area; if at least two of the three quantitative indicators are in a low-risk interval, then the area where the grounding grid is located is determined to be a low-risk area; and outputting the lightning risk level of the area where the grounding grid is located.

[0013] As a preferred solution of the method for guiding the grounding grid resistance reduction transformation described in the present invention, the urgency of the grounding grid transformation is evaluated through the grounding grid transformation urgency evaluation model, including the following steps: by analyzing the environmental information of the area where the grounding grid is located and the technical factors that cause the maximum ground potential rise to exceed the standard, the key factors affecting the grounding grid transformation are identified; the analytic hierarchy process is used to establish a grounding grid transformation urgency index system and determine the weight of each index; a grounding grid transformation urgency evaluation model is constructed; by inputting actual measurement data into the grounding grid transformation urgency evaluation model, a quantitative evaluation value L of the transformation urgency is obtained; and the transformation urgency level is divided and output according to the quantitative evaluation value.

[0014] As a preferred solution of the method for guiding the grounding grid resistance reduction transformation of the present invention, the specific formula of the grounding grid transformation urgency assessment model is as follows:

[0015]

[0016] Among them, L is the quantitative assessment value, λ1, λ2, and λ3 are the weights of the ground impedance exceeding the standard, the ground potential rising exceeding the standard, and the lightning risk level, respectively, R2 is the actual value of the ground impedance, R0 is the design value of the ground impedance, U is the ground potential rising value, and U max is the maximum allowable value of ground potential rise, and D is the lightning risk value.

[0017] As a preferred scheme of the method for guiding the grounding grid resistance reduction transformation described in the present invention, the grounding grid transformation urgency index system includes the highest layer, the middle layer and the lowest layer, the highest layer is the overall target layer, the middle layer is the criterion layer, the criterion layer includes the degree of exceeding the grounding impedance, the degree of exceeding the ground potential rise, and the degree of lightning risk, and the lowest layer is the indicator layer, and the indicator layer includes the actual value of the grounding impedance R2, the ground potential rise value U, and the lightning risk value D.

[0018] In the second aspect, an embodiment of the present invention provides a system for guiding the resistance reduction and transformation of a grounding grid, which includes a grounding impedance testing module, which is used to obtain a grounding impedance test value and a grounding impedance design value of a grounding grid to be transformed; a grounding impedance comparison module, which is used to calculate an actual grounding impedance value, and compare the actual grounding impedance value with the grounding impedance design value to determine whether the design requirements are met; a ground potential rise calculation module, which is used to obtain the maximum short-circuit current of the system and calculate the ground potential rise when the grounding grid short-circuit fault occurs if the design requirements are not met; a ground potential rise evaluation module, which is used to evaluate whether the ground potential rise meets the standard requirements and obtain environmental information of the area where the grounding grid is located; a transformation urgency evaluation module, which is used to construct a grounding grid transformation urgency evaluation model based on environmental information, evaluate the urgency of the grounding grid transformation through the grounding grid transformation urgency evaluation model, and output the transformation urgency level; a differentiated transformation measures module, which is used to take corresponding differentiated transformation measures for different transformation urgency levels to complete the grounding grid resistance reduction and transformation.

[0019] In a third aspect, an embodiment of the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the method for guiding the grounding grid resistance reduction transformation as described in the first aspect of the present invention are implemented.

[0020] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the method for guiding the grounding grid resistance reduction transformation as described in the first aspect of the present invention are implemented.

[0021] The beneficial effects of the present invention are as follows: the present invention systematically analyzes the environmental information and technical factors of the area where the grounding grid is located, accurately identifies the key factors that affect the transformation, and lays the foundation for the establishment of the subsequent indicator system and evaluation model. The analytic hierarchy process is used to construct an indicator system for the urgency of grounding grid transformation, and the weights of various indicators are scientifically determined, providing a basis for quantitatively evaluating the urgency of transformation. According to different levels of transformation urgency, differentiated transformation measures are proposed to ensure rapid transformation in emergency situations, while taking into account preventive maintenance under normal circumstances, so as to better meet the needs of safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1A flow chart to guide the grounding grid resistance reduction transformation method.

[0024] Figure 2 A flowchart for assessing the urgency of transformation to guide grounding grid resistance reduction transformation methods.

[0025] Figure 3 Computer equipment diagram to guide the grounding grid resistance reduction transformation method. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] Example 1

[0030] Reference Figure 1 to Figure 3 , which is the first embodiment of the present invention, and provides a method for guiding the transformation of grounding grid resistance reduction, comprising:

[0031] S1: Obtain the grounding impedance test value R1 and the shunt coefficient test value k of the grounding grid to be modified, determine the grounding impedance design value R0, and calculate the actual grounding impedance value R2.

[0032] Among them, the process of determining the grounding impedance design value R0 is as follows: according to the regional environmental characteristics (such as soil resistivity, etc.), the optimization range of the grounding impedance design value R0 is preliminarily determined; combined with the maximum short-circuit current of the system, the upper limit of the grounding impedance design value R0 is limited to ensure that the grounding network can effectively discharge the short-circuit current in the event of a short-circuit fault; using a quantitative analysis method, comprehensively considering the regional environmental characteristics and short-circuit current, the final grounding impedance design value R0 is determined within the optimization range.

[0033] It should be noted that the calculation formula for the actual value of ground impedance is as follows:

[0034]

[0035] Among them, R2 is the actual value of grounding impedance, R0 is the design value of grounding impedance, and k is the test value of shunt coefficient.

[0036] S2: Compare the actual value R2 of the grounding impedance with the design value R0 of the grounding impedance to determine whether the actual value R2 of the grounding impedance meets the design requirements.

[0037] Specifically, if R2 is less than or equal to R0, it is determined that the grounding impedance of the grounding array meets the design requirements; if R2 is greater than R0, it is determined that the grounding impedance of the grounding array does not meet the design requirements.

[0038] Among them, the design requirement refers to the ground impedance design value R0.

[0039] S3: If the design requirements are not met, obtain the maximum short-circuit current of the system and calculate the ground potential rise when the grounding grid is short-circuited.

[0040] Specifically, obtain the maximum short-circuit current I of the system sc ; According to the maximum short-circuit current I sc and the actual value of ground impedance R2, calculate the ground potential rise U when the grounding network is short-circuited p , the specific formula is as follows:

[0041] U p =I sc *R2

[0042] Among them, R2 is the actual value of ground impedance, I sc is the maximum short-circuit current, U p is the maximum ground potential rise value.

[0043] S4: Evaluate whether the ground potential rise meets the standard requirements and output environmental information and technical factors.

[0044] Specifically, the following steps are included: setting a standard limit value for the maximum ground potential rise value; evaluating the maximum ground potential rise value U p Whether it exceeds the standard limit; if U p If the standard limit is not exceeded, no grounding grid modification is required; if U p If the standard limit is exceeded, the environmental information of the area where the grounding grid is located is obtained, combined with the maximum ground potential rise value U p and environmental information, analyze the technical factors that cause the maximum ground potential rise to exceed the standard; output the environmental information of the area where the grounding grid is located and the technical factors that cause the maximum ground potential rise to exceed the standard.

[0045] Among them, the standard limit refers to the maximum ground potential rise requirement specified in the relevant grounding system design technical specifications, and the environmental information includes lightning risk level, surrounding satellite map information and site soil structure information.

[0046] It should be noted that the process of determining the lightning risk level is as follows: obtain lightning monitoring data of the area where the grounding grid is located, including lightning ground flash density, lightning strike frequency, and lightning intensity; use deep learning algorithms to analyze lightning monitoring data to identify the characteristics of lightning activity in the area where the grounding grid is located, including the time distribution, geographical distribution, and polarity distribution of lightning occurrence; design quantitative indicators based on the identified lightning activity characteristics, including lightning occurrence frequency index, lightning concentration index, and lightning intensity index; determine the lightning risk level of the area where the grounding grid is located by analyzing the first quantitative indicator; determine the lightning risk value of the area where the grounding grid is located based on the lightning risk level; output the lightning risk level and lightning risk value of the area where the grounding grid is located.

[0047] Preferably, the risk level includes three levels: high-prone area, medium-prone area and low-prone area, and the specific classification is based on the following: calculate three quantitative indicators of the area where the grounding grid is located, including lightning frequency index, lightning concentration index and lightning intensity index; determine the lightning risk level according to the risk range of the three quantitative indicators; if at least two of the three quantitative indicators are in the high-risk range, the area is determined to be a high-prone area; if two of the three quantitative indicators are in the medium-risk range, the area is determined to be a medium-prone area; if at least two of the three quantitative indicators are in the low-risk range, the area is determined to be a low-prone area.

[0048] It should be noted that the lightning frequency index, lightning concentration index and lightning intensity index are used to reflect the frequency, concentration and intensity of lightning in the area. Their calculation formulas are: the ratio of lightning ground flash density to the annual average lightning ground flash density, the ratio of the standard deviation of lightning occurrence points to the average lightning occurrence point spacing, and the ratio of the maximum lightning current peak to the average lightning current peak. For the lightning frequency index, when it is greater than 1, it belongs to the high risk range, between 0.5 and 1, it belongs to the medium risk range, and less than 0.5, it belongs to the low risk range. For the lightning concentration index, when it is greater than 1, it belongs to the high risk range, between 0.5 and 1, it belongs to the medium risk range, and less than 0.5, it belongs to the low risk range. For the lightning intensity index, when it is greater than 2, it belongs to the high risk range, between 1 and 2, it belongs to the medium risk range, and less than 1, it belongs to the low risk range.

[0049] Preferably, by taking the above-mentioned transformation measures, the grounding impedance can be effectively reduced so that the ground potential increase value meets the requirements of the technical standard limit. In addition, uploading the environmental information of the area where the grounding grid is located will help to better analyze the technical reasons for the increase in ground potential, and provide a basis for subsequent optimization and transformation of the grounding grid, thereby improving the pertinence and effectiveness of the transformation plan.

[0050] S5: Construct a grounding grid transformation urgency assessment model based on environmental information and technical factors, evaluate the urgency of grounding grid transformation through the grounding grid transformation urgency assessment model, and output the transformation urgency level.

[0051] Specifically, the following steps are included:

[0052] S5.1: Identify the key factors affecting the transformation of the grounding grid by analyzing the environmental information of the area where the grounding grid is located and the technical factors that cause the maximum ground potential rise to exceed the standard.

[0053] Preferably, collect environmental information of the area where the grounding grid is located, including lightning risk level, surrounding satellite map information and soil structure information of the site; analyze the technical factors that lead to excessive maximum ground potential rise, such as the structural design, material selection, installation quality and aging corrosion of the grounding device; analyze the correlation between various environmental and technical factors and the grounding grid transformation, and determine the key factors that have a greater impact on the urgency of the transformation; based on the analysis results, determine the lightning risk level, surrounding environmental corrosion, and soil resistivity as key factors.

[0054] S5.2: Use the analytic hierarchy process to establish an indicator system for the urgency of grounding grid transformation and determine the weight of each indicator.

[0055] Preferably, according to the identified key factors, the hierarchical structure of the grounding grid transformation urgency index system is determined to include the highest level, the middle level and the lowest level. Among them, the highest level is the overall target level, that is, the urgency of grounding grid transformation; the middle level is the criterion level, including the degree of grounding impedance exceeding the standard, the degree of ground potential rising exceeding the standard, and the degree of lightning risk; the lowest level is the indicator level, including the actual value of grounding impedance R2, the ground potential rising value U, and the lightning risk value D.

[0056] Furthermore, a judgment matrix of the hierarchical analysis method is constructed to compare the relative importance of the indicators of each criterion layer in the overall target layer, and the weight of each indicator is obtained. In the present invention, after analysis, the weight of the ground impedance exceeding the standard level L1 is 40%, the weight of the ground potential rising exceeding the standard level L2 is 30%, and the weight of the lightning risk level L3 is 30%.

[0057] Preferably, the grounding grid reconstruction urgency assessment method can not only comprehensively and objectively reflect the key factors affecting the urgency of grounding grid reconstruction, but also the determined indicator weights are in line with the actual situation, which is helpful to accurately locate the key points, difficulties and weak links of grounding grid reconstruction, and provide an important basis for formulating practical grounding grid reconstruction plans.

[0058] S5.3: Construct a grounding grid transformation urgency assessment model.

[0059] Preferably, the specific formula of the grounding grid transformation urgency assessment model is as follows:

[0060]

[0061] Among them, L is the quantitative assessment value, λ1, λ2, and λ3 are the weights of the ground impedance exceeding the standard, the ground potential rising exceeding the standard, and the lightning risk level, respectively, R2 is the actual value of the ground impedance, R0 is the design value of the ground impedance, U is the ground potential rising value, and U max is the maximum allowable value of ground potential rise, and D is the lightning risk value.

[0062] It should be noted that U max It needs to be determined based on on-site environmental conditions and technical standard requirements.

[0063] S5.4: By inputting the actual measurement data into the grounding grid transformation urgency assessment model, a quantitative assessment value L of the transformation urgency is obtained.

[0064] S5.5: Classify and output the level of urgency for renovation based on the quantitative assessment value.

[0065] Specifically, set the urgency level division thresholds L1 and L2; calculate the L value through the quantitative evaluation model, and perform level division in combination with the dynamic threshold: if L>L2, the output transformation urgency level is urgent; if L1≤L≤L2, the output transformation urgency level is key; if L<L1, the output transformation urgency level is general.

[0066] It should be noted that in actual applications, the urgency level thresholds L1 and L2 are dynamically adjusted based on the following factors: the safety production and risk control requirements of the project area, the use environment of the grounding network equipment, the urgency requirements of the superior competent department for such projects, and the overall investment budget and construction schedule of the renovation project. By dynamically adjusting the urgency level thresholds, it can be ensured that the renovation urgency assessment results are more in line with the actual situation.

[0067] S6: According to different levels of renovation urgency, take corresponding differentiated renovation measures to complete the grounding grid resistance reduction renovation.

[0068] Furthermore, the present embodiment also provides a system for guiding the resistance reduction and transformation of a grounding grid, including a grounding impedance test module, which is used to obtain the grounding impedance test value and the grounding impedance design value of the grounding grid to be transformed; a grounding impedance comparison module, which is used to calculate the actual value of the grounding impedance, and compare the actual value of the grounding impedance with the design value of the grounding impedance to determine whether the design requirements are met; a ground potential rise calculation module, which is used to obtain the maximum short-circuit current of the system and calculate the ground potential rise when the grounding grid short-circuit fault occurs if the design requirements are not met; a ground potential rise evaluation module, which is used to evaluate whether the ground potential rise meets the standard requirements and obtain environmental information of the area where the grounding grid is located; a transformation urgency evaluation module, which is used to construct a grounding grid transformation urgency evaluation model based on environmental information, evaluate the urgency of the grounding grid transformation through the grounding grid transformation urgency evaluation model, and output the transformation urgency level; a differentiated transformation measures module, which is used to take corresponding differentiated transformation measures for different transformation urgency levels to complete the grounding grid resistance reduction and transformation.

[0069] This embodiment also provides a computer device, which is suitable for guiding the method of reducing the resistance of the grounding grid, including a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the method of guiding the grounding grid resistance reduction transformation as proposed in the above embodiment.

[0070] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0071] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for guiding the transformation of grounding grid resistance reduction as proposed in the above embodiment is implemented.

[0072] In summary, the present invention systematically analyzes the environmental information and technical factors of the area where the grounding grid is located, accurately identifies the key factors that affect the transformation, and lays the foundation for the establishment of the subsequent indicator system and evaluation model. The analytic hierarchy process is used to construct an indicator system for the urgency of grounding grid transformation, and the weights of various indicators are scientifically determined, providing a basis for quantitative evaluation of the urgency of transformation. According to different levels of transformation urgency, differentiated transformation measures are proposed to ensure rapid transformation in emergency situations, while taking into account preventive maintenance under normal circumstances, so as to better meet the needs of safe and stable operation of the power system.

[0073] Example 2

[0074] Reference Figure 1 to Figure 3 , which is the second embodiment of the present invention. This embodiment provides a method for guiding the resistance reduction transformation of the grounding grid. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0075] At the beginning of a substation grounding grid renovation project, the grounding impedance test value of the grounding grid to be renovated was first obtained as 0.48Ω, and the shunt coefficient test value k was 0.85. According to the soil resistivity of the site (about 100Ω·m) and the maximum short-circuit current of the system (40kA), the grounding impedance design value was determined to be 0.3Ω. Subsequently, the actual value of the grounding impedance was calculated to be 0.41Ω according to the formula.

[0076] Next, the actual value of the grounding impedance, 0.41Ω, was compared with the designed value of the grounding impedance, 0.3Ω, and it was found that the actual value of the grounding impedance was greater than the designed value, so it was determined that the grounding impedance of the grounding array did not meet the design requirements. In view of this, the project team obtained the maximum short-circuit current of the system, 40kA, and calculated the ground potential rise of 16.4kV when the grounding grid was short-circuited according to the formula.

[0077] Subsequently, the project team evaluated whether the ground potential rise met the standard requirements. According to relevant technical specifications, the maximum ground potential rise standard limit of the substation is 15kV. After evaluation, it was found that the calculated maximum ground potential rise of 16.4kV exceeded the standard limit. Therefore, the project team further obtained environmental information about the area where the grounding grid was located, including lightning risk level, surrounding satellite map information, and soil structure information of the site.

[0078] By analyzing the lightning monitoring data in the area where the grounding grid is located, the project team used a deep learning algorithm to identify the characteristics of lightning activity in the area. The lightning frequency index was calculated to be 1.2, the lightning concentration index was 0.8, and the lightning intensity index was 1.5. Based on these indicators, the area was determined to be a medium-prone area, and the lightning risk value was 0.7.

[0079] Based on the collected environmental information and technical factors, the project team built an assessment model for the urgency of grounding grid transformation. Through the analytic hierarchy process, the weights of the grounding impedance exceeding the standard, the ground potential rise exceeding the standard, and the lightning risk level were determined to be 40%, 30%, and 30%, respectively. The actual measurement data was input into the assessment model, and the quantitative assessment value of the urgency of transformation was 0.68.

[0080] Finally, according to the preset urgency level threshold (L1 = 0.8, L2 = 0.5), the project team determined the urgency level of the grounding grid transformation as "key". Based on this result, the project team formulated corresponding differentiated transformation measures, including increasing the number of grounding electrodes, optimizing the grounding grid layout, etc., to complete the grounding grid resistance reduction transformation.

[0081] By taking the above-mentioned transformation measures, the grounding impedance of the grounding grid was reduced to 0.28Ω, and the ground potential rise value was reduced to 11.2kV, successfully meeting the requirements of the technical standard limit.

[0082] Preferably, the comparison indicators of the present invention and the traditional method are shown in Table 1.

[0083] Table 1 Comparison indexes of the present invention and the traditional method

[0084]

[0085] As can be seen from Table 1, the present invention is superior to the traditional method in many aspects. First, the ground impedance measurement accuracy of the present invention reaches 93%, which is 8 percentage points higher than the traditional method, which helps to more accurately evaluate the actual condition of the grounding grid. Secondly, the error in the calculation of the ground potential rise value of the present invention is only ±3%, which is much lower than the ±7% of the traditional method, which makes the subsequent transformation decision more reliable. In terms of efficiency, the present invention significantly shortens the transformation urgency assessment time and the transformation plan formulation time, which only requires 1 / 4 and 1 / 3 of the traditional method respectively, greatly improving the work efficiency. In terms of transformation effect, the method of the present invention reduces the ground impedance by 31.7%, and the ground potential rise value is also reduced by 31.7%, both of which are better than the 20% and 22% of the traditional method. This shows that the present invention can more effectively improve the performance of the grounding grid. Finally, in terms of economy, although the present invention adopts more advanced technology and more comprehensive evaluation methods, its transformation cost is saved by 10%, reflecting a higher cost-effectiveness ratio.

[0086] The simulation experiment data shows that this technical solution can effectively evaluate the urgency of grounding grid transformation in practical applications and guide the implementation of the transformation work, thereby improving the safety and reliability of the power system.

[0087] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for guiding the transformation of grounding grid resistance reduction, characterized in that: include, Obtain the grounding impedance test value and grounding impedance design value of the grounding grid to be modified, and calculate the actual value of the grounding impedance; Comparing the actual value of the grounding impedance with the designed value of the grounding impedance to determine whether the actual value of the grounding impedance meets the design requirements; If the actual value of the grounding impedance does not meet the design requirements, the maximum short-circuit current of the system is obtained, and the ground potential rise value when the grounding grid is short-circuited is calculated; Evaluate whether the ground potential rise meets the standard requirements and obtain environmental information of the area where the grounding grid is located; Building a grounding grid transformation urgency assessment model based on the environmental information, assessing the urgency of grounding grid transformation through the grounding grid transformation urgency assessment model, and outputting a transformation urgency level; According to the different levels of urgency of transformation, corresponding differentiated transformation measures are taken to complete the transformation of grounding grid resistance reduction.

2. The method for guiding grounding grid resistance reduction transformation according to claim 1, characterized in that: The calculation formula of the actual value of the ground impedance is as follows: Among them, R2 is the actual value of grounding impedance, R0 is the design value of grounding impedance, and k is the test value of shunt coefficient.

3. The method for guiding grounding grid resistance reduction transformation according to claim 1, characterized in that: The evaluation of whether the ground potential rise meets the standard requirements includes: Set standard limits for maximum ground potential rise; Evaluate the maximum ground potential rise value U p Whether it exceeds the standard limit; If U p If the standard limit is not exceeded, there is no need to modify the grounding grid; If U p If the standard limit is exceeded, the environmental information of the area where the grounding grid is located is obtained, and the maximum ground potential rise value U p Analyze the technical factors that lead to the maximum ground potential rise exceeding the standard with the environmental information; The environmental information includes lightning risk level, surrounding satellite map information and site soil structure information.

4. The method for guiding grounding grid resistance reduction transformation as claimed in claim 3, characterized in that: The confirmation process of the lightning risk level is as follows: Obtaining lightning monitoring data of the area where the grounding grid is located, wherein the lightning monitoring data includes lightning ground flash density, lightning strike frequency, and lightning intensity; Analyze the lightning monitoring data using a deep learning algorithm to identify the characteristics of lightning activity in the area where the grounding grid is located; Designing quantitative indicators according to the characteristics of the lightning activity, wherein the quantitative indicators include a lightning frequency index, a lightning concentration index, and a lightning intensity index; The lightning risk level of the area where the grounding grid is located is determined by analyzing the quantitative indicators, including: If at least two of the three quantitative indicators are in the high-risk range, the area where the grounding grid is located is determined to be a high-risk area; If two of the three quantitative indicators are in the medium risk range, the area where the grounding grid is located is judged to be a medium-prone area; If at least two of the three quantitative indicators are in the low risk range, the area where the grounding grid is located is judged to be a low-risk area; Output the lightning risk level of the area where the grounding grid is located.

5. The method for guiding grounding grid resistance reduction transformation according to claim 1, characterized in that: The evaluating the urgency of grounding grid transformation by using the grounding grid transformation urgency evaluation model comprises the following steps: By analyzing the environmental information of the grounding grid area and the technical factors that cause the maximum ground potential to exceed the standard, the key factors affecting the grounding grid transformation are identified; The analytic hierarchy process was used to establish the urgency index system for grounding grid transformation and determine the weight of each index; Construct a grounding grid transformation urgency assessment model; By inputting actual measurement data into the grounding grid transformation urgency assessment model, a quantitative assessment value L of transformation urgency is obtained; The transformation urgency level is divided and output according to the quantitative evaluation value.

6. The method for guiding grounding grid resistance reduction transformation according to claim 5, characterized in that: The specific formula of the grounding grid transformation urgency assessment model is as follows: Among them, L is the quantitative assessment value, λ1, λ2, and λ3 are the weights of the ground impedance exceeding the standard, the ground potential rising exceeding the standard, and the lightning risk level, respectively, R2 is the actual value of the ground impedance, R0 is the design value of the ground impedance, U is the ground potential rising value, and U max is the maximum allowable value of ground potential rise, and D is the lightning risk value.

7. The method for guiding grounding grid resistance reduction transformation according to claim 5, characterized in that: The grounding grid transformation urgency index system includes the highest layer, the middle layer and the lowest layer, the highest layer is the overall target layer, the middle layer is the criterion layer, the criterion layer includes the degree of exceeding the standard for grounding impedance, the degree of exceeding the standard for ground potential rise, and the degree of lightning risk, and the lowest layer is the indicator layer, which includes the actual value of grounding impedance R2, the ground potential rise value U, and the lightning risk value D.

8. A system for guiding the transformation of grounding grid resistance reduction, based on the method for guiding the transformation of grounding grid resistance reduction according to any one of claims 1 to 7, characterized in that: Also includes, A ground impedance test module is used to obtain the ground impedance test value and the ground impedance design value of the ground grid to be modified; A ground impedance comparison module is used to calculate an actual ground impedance value, and compare the actual ground impedance value with the designed ground impedance value to determine whether the design requirements are met; The ground potential rise calculation module is used to obtain the maximum short-circuit current of the system and calculate the ground potential rise when the grounding grid short-circuit fault occurs if the design requirements are not met; A ground potential increase evaluation module, used to evaluate whether the ground potential increase meets the standard requirements and obtain environmental information of the area where the grounding grid is located; A transformation urgency assessment module, used to construct a grounding grid transformation urgency assessment model based on the environmental information, evaluate the urgency of grounding grid transformation through the grounding grid transformation urgency assessment model, and output a transformation urgency level; The differentiated transformation measures module is used to take corresponding differentiated transformation measures according to different transformation urgency levels to complete the grounding grid resistance reduction transformation.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for guiding the grounding grid resistance reduction transformation according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for guiding the grounding grid resistance reduction transformation according to any one of claims 1 to 7 are implemented.

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