CN112485303A - Method and system for analyzing characteristic parameters of soil multi-impact discharge - Google Patents
Method and system for analyzing characteristic parameters of soil multi-impact discharge Download PDFInfo
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Abstract
The invention discloses a method and a system for analyzing characteristic parameters of soil multiple-time impact discharge, wherein the method comprises the following steps: acquiring basic data, and constructing a three-dimensional space structure of a discharge channel based on the basic data; performing first impulse discharge characteristic parameter inversion calculation through a first numerical calculation model to obtain the residual resistivity of the impulse discharge of the soil medium under the first impact action and the equivalent critical breakdown electric field intensity; judging a multi-impact discharge channel structure and constraint conditions according to the three-dimensional space structure of the discharge channel; and performing subsequent impulse discharge characteristic parameter inversion calculation through a subsequent numerical calculation model after initialization setting to obtain the residual resistivity and the equivalent critical breakdown electric field intensity when the soil medium is subjected to secondary breakdown. According to the invention, the actual lightning multi-impact discharge channel structure is considered, the discharge characteristic parameter is subjected to numerical simulation calculation, the discharge characteristic parameter which is more consistent with the actual condition is obtained, and the accuracy and reliability of the detection of the lightning electrical parameter of the soil are improved.
Description
Technical Field
The invention belongs to the technical field of detection of grounding characteristics of power systems, and particularly relates to a method and a system for analyzing characteristic parameters of soil multiple-time impact discharge.
Background
The soil medium is used as a main flow dispersing medium of the grounding system, the accuracy of the value of the impact discharge characteristic parameter directly determines whether the lightning stroke transient model calculation result of the grounding system is correct, and the calculation method of the soil lightning stroke discharge parameter is one of the key research contents in the grounding field.
The characteristic parameters of the soil impulse discharge mainly comprise the critical breakdown field intensity E of the soilcAnd residual resistivity p of discharge regionres. Because transient parameters in the discharging process are difficult to directly measure, most of the existing research results are obtained by calculation based on a numerical analysis model, and the dependence degree of the accuracy of the calculation results on the accuracy of the model is extremely high. However, the soil medium has a strong isolation effect on light and heat, and the discharge condition in the ground is difficult to observe, so that the existing calculation models are all based on artificial assumption conditions to different degrees. The existing analysis model is mostly established based on the assumption that each direction of uniform dispersion flow after lightning enters the groundHowever, the latest research and observation results show that a strip-shaped centralized discharge channel is formed after lightning enters the ground, and the main current is discharged along the path, so that the calculation result of the uniform current dispersion model has a large difference from the actual situation, and the difference of the existing calculation result is large due to the difference of various assumed models, the span of the value range is large, and the practical application of engineering is difficult.
In addition, lightning has the characteristic of one-time breakdown and multiple-time discharge, and one lightning stroke has 3-5 subsequent impacts on average. The existing parameter calculation method and support data are all based on a single impulse discharge result, the lightning multi-impulse condition is not considered, and the discharge attenuation characteristic and the recovery characteristic of a soil medium are ignored. The soil medium is in a high ionization state after ionization and can last for a period of time after the discharge is finished. The ionization recovery degree of the discharge area also directly influences the reliability of the subsequent impact discharge characteristic parameter value, thereby influencing the lightning stroke electrical parameter detection precision of the environmental soil.
Disclosure of Invention
The invention provides a soil multi-impact discharge characteristic parameter analysis method, aiming at solving the problems that the existing soil impact discharge characteristic parameter numerical simulation method is limited and the lightning stroke electrical parameter detection precision of the soil in the grounding environment is influenced. The method can realize the analysis and calculation of the lightning multi-impulse discharge characteristic parameters of the soil medium under different conditions, and improve the lightning electrical parameter detection precision of various types of grounding environment soil.
The invention is realized by the following technical scheme:
a method for analyzing characteristic parameters of soil multiple-impact discharge comprises the following steps:
acquiring basic data, and constructing a three-dimensional space structure of a discharge channel based on the basic data;
secondly, constructing a first numerical calculation model based on the three-dimensional space structure of the discharge channel, and performing first impulse discharge characteristic parameter inversion calculation through the first numerical calculation model to obtain the residual resistivity of the soil medium impulse discharge under the first impact action and the equivalent critical breakdown electric field intensity;
judging a multi-impact discharge channel structure and a constraint condition according to the three-dimensional space structure of the discharge channel to obtain the constraint condition in the subsequent impact discharge parameter calculation process;
and fourthly, constructing a subsequent numerical calculation model based on the three-dimensional space structure of the discharge channel, carrying out initialization setting on the subsequent numerical calculation model according to the constraint conditions obtained in the third step, and carrying out subsequent impulse discharge characteristic parameter inversion calculation on the subsequent numerical calculation model after initialization setting to obtain the residual resistivity and the equivalent critical breakdown electric field intensity when the soil medium is subjected to secondary breakdown.
Preferably, the basic data collected in the first step of the method comprises electrical parameters and structural parameters;
the electrical parameters comprise voltage and current waveform parameters on the soil medium in the continuous impulse discharge process and electrical parameters of the soil medium; the electrical parameters are obtained through a grounding system continuous impulse discharge measurement experiment platform;
the structural parameters comprise the actual space structure of the underground discharge channel and the physical structural parameters of the soil discharge environment; the structural parameters are obtained through a soil discharge X-ray projection imaging observation platform.
Preferably, step one of the present invention is to construct a three-dimensional space structure of the discharge channel based on the obtained structural parameters.
Preferably, the first impulse discharge characteristic parameter inversion calculation in step two of the present invention specifically comprises:
taking a first impact current value obtained by a test as excitation of a first numerical calculation model, and taking an impact voltage value as a standard response;
in the first numerical calculation model, iterative inversion calculation is carried out on the resistivity of the soil in the discharge channel region from an initial value until the calculated voltage is consistent with the standard response, at the moment, the resistivity of the soil in the discharge channel is the residual resistivity of the soil medium impact discharge under the first impact action, and the electric field intensity in the discharge channel is the equivalent critical breakdown electric field intensity.
Preferably, the determination process of the present invention specifically includes:
3.1, performing three-dimensional reconstruction of a discharge channel space structure according to the shot three views of the underground discharge channel structure;
3.2, judging the type of a discharge channel based on the reconstructed three-dimensional space structure, and dividing a discharge area;
and 3.3, obtaining constraint conditions in the subsequent impulse discharge parameter calculation process based on the divided discharge areas.
Preferably, step 3.3 of the present invention specifically is:
in the process of the first impulse discharge, only the first impulse discharge channel is generated, the subsequent impulse discharge does not occur, and the characteristic parameters of the first impulse discharge are obtained through the second step;
in the subsequent impulse discharge process, the newly generated soil medium in the subsequent impulse discharge area is firstly punctured, so that the residual resistivity presented by the newly generated soil medium is consistent with the residual resistivity of the first punctured impulse discharge channel; at this time, in the first impulse discharge area and the multi-impulse-channel overlapping area, because of different recovery degrees and different magnitudes of the shunted impulse currents, the residual resistivity presented at this time is unknown, that is, the residual resistivity presented when the soil medium is subjected to secondary breakdown discharge in the multi-impulse discharge process, that is, the residual resistivity of the soil after-impulse discharge.
Preferably, the initialization setting in step four of the present invention is specifically: and setting the resistivity of the subsequent impact discharge area as the residual resistivity of the soil first breakdown discharge obtained in the step two, setting the resistivity of the first impact discharge area and the superposed area of the multiple impact channels as unknown quantity, and setting the initial value as the residual resistivity of the soil first impact discharge obtained in the step two.
Preferably, the inversion calculation of the characteristic parameters of the impulse discharge after the four steps of the method specifically comprises the following steps:
taking a subsequent impact current value obtained by the test as excitation, and taking a subsequent impact voltage value as a standard response;
in the subsequent numerical calculation model, iterative inversion calculation is carried out on the resistivity of the first impulse discharge area and the resistivity of the multi-impulse-channel overlapping area from an initial value until the calculated voltage is consistent with the standard response, the calculated soil resistivity of the first impulse discharge area and the multi-impulse-channel overlapping area is the residual resistivity of the soil medium under the corresponding condition when the soil medium is subjected to secondary breakdown, and the mean value of the electric field intensity in the area is the equivalent critical breakdown electric field intensity.
Preferably, the method of the present invention further comprises:
and step five, recording the residual resistivity and the critical breakdown strength of the soil obtained by calculation in the step two and the step four, and the corresponding soil property and the electrical parameter together, outputting and storing.
On the other hand, the invention also provides a soil multiple-impact discharge characteristic parameter analysis system, which comprises a data acquisition module, a three-dimensional module, a first parameter analysis module, a constraint condition module and a subsequent parameter analysis module;
the data acquisition module is used for acquiring basic data;
the three-dimensional module constructs a three-dimensional space structure of the discharge channel based on basic data;
the first parameter analysis module is used for constructing a first numerical calculation model based on the three-dimensional space structure of the discharge channel, and performing first impulse discharge characteristic parameter inversion calculation through the first numerical calculation model to obtain the residual resistivity of the impact discharge of the soil medium under the first impact action and the equivalent critical breakdown electric field intensity;
the constraint condition module judges a multi-impact discharge channel structure and constraint conditions according to the three-dimensional space structure of the discharge channel to obtain the constraint conditions in the subsequent impact discharge parameter calculation process;
the subsequent parameter analysis module constructs a subsequent numerical calculation model based on the three-dimensional space structure of the discharge channel, performs initialization setting on the subsequent numerical calculation model according to the constraint conditions obtained by the constraint condition module, and performs subsequent impulse discharge characteristic parameter inversion calculation through the subsequent numerical calculation model after initialization setting to obtain the residual resistivity and the equivalent critical breakdown electric field intensity when the soil medium is secondarily broken down.
The invention has the following advantages and beneficial effects:
1. according to the soil multi-impact discharge characteristic parameter analysis method and system provided by the invention, the actual lightning multi-impact discharge channel structure is considered, the discharge characteristic parameter is subjected to numerical simulation calculation, and the discharge characteristic parameter which is more consistent with the actual condition can be obtained, so that the lightning stroke electrical parameter detection precision and reliability of soil are improved.
2. The invention has wide application range, is convenient to realize, and is suitable for detecting the lightning stroke electrical parameters of various earthed environment soils.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a schematic flow chart of a soil multi-impact discharge characteristic parameter analysis method of the invention.
FIG. 2 is a gray scale diagram of the discharge channel structure of the present invention.
FIG. 3 is a three-dimensional spatial structure model diagram of the discharge channel of the present invention.
FIG. 4 is a schematic block diagram of a soil multi-impact discharge characteristic parameter analysis system of the present invention.
In the figure: 1 metal vertical electrode, 2 first impact discharge channel, 3 subsequent impact discharge channel.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
Compared with the existing numerical simulation analysis method, the embodiment provides a method for analyzing the characteristic parameters of the multiple times of soil impact discharge.
Specifically, as shown in fig. 1, the method of this embodiment mainly includes the following steps:
the method comprises the steps of collecting basic data and constructing a three-dimensional space structure of a discharge channel based on the basic data.
The basic data collected in the first step of this embodiment includes electrical parameters and structural parameters, where the electrical parameters include voltage and current waveform parameters on the soil medium during continuous impulse discharge, and electrical parameters of the soil medium, such as soil resistivity; the structural parameters comprise the actual space structure of the discharge channel in the ground and the physical structural parameters of the soil discharge environment.
The electrical parameters of the present embodiment can be obtained based on the experimental platform for continuous impulse discharge measurement of the grounding system.
The structural parameters of the present embodiment can be obtained based on a soil discharge X-ray transmission imaging observation platform.
In this embodiment, a three-dimensional structure of a discharge channel and a discharge environment is constructed based on the obtained structural parameters.
And secondly, constructing a primary numerical calculation model based on the three-dimensional space structure of the discharge channel, and performing primary impulse discharge characteristic parameter inversion calculation through the primary numerical calculation model to obtain the residual resistivity of the impulse discharge of the soil medium under the primary impact action and the equivalent critical breakdown electric field strength.
The first impulse discharge characteristic parameter inversion calculation in the second step of this embodiment specifically includes:
and constructing a finite element numerical calculation model on the basis of the three-dimensional structures of the discharge channel and the discharge environment, taking the initial impact current value obtained by the test as excitation, and taking the impact voltage value as standard response. In the numerical model, iterative inversion calculation is carried out on the resistivity of the soil in the discharge channel region from an initial value until the calculated voltage is consistent with the standard response. At the moment, the resistivity of the soil in the discharge channel is the residual resistivity of the soil medium impact discharge under the first impact action, and the mean value of the electric field intensity in the discharge channel is the equivalent critical breakdown electric field intensity.
And step three, judging the structure and the constraint condition of the multi-impact discharge channel according to the three-dimensional space structure of the discharge channel, and obtaining the constraint condition in the subsequent impact discharge parameter calculation process.
In the third step of this embodiment, the structure and the constraint condition of the multi-impulse discharge channel are determined, and the constraint condition in the subsequent impulse discharge parameter calculation process is set mainly based on the branch condition of the multi-impulse discharge channel and the soil discharge mechanism. The underground discharge channel has a complex and changeable structure and can be generally classified into: fully coincident single channel structures, partially coincident branched structures, and multi-channel structures. The discharge channel structure can be further divided into: the method comprises the following steps of firstly, impacting a discharge area for the first time, secondly, impacting a discharge area for the subsequent time, and thirdly, overlapping an area of multiple impact channels.
Firstly, three-dimensional reconstruction of the space structure of the discharge channel is carried out according to the shot three-view image of the underground discharge channel structure, experimental observation and theoretical analysis show that the main body of the discharge channel is of a variable-diameter-like cylindrical structure, and the actual space structure can be accurately restored based on the phenomenon and the three-view image of the discharge channel. Then, the type of the discharge channel is judged according to the actual three-dimensional space structure of the discharge channel, and the discharge area is divided.
In the process of the first impulse discharge, only the first impulse discharge channel is generated, the subsequent impulse discharge does not occur, and the first impulse discharge characteristic parameter is calculated in an inversion mode in the step two.
After the first impulse discharge is finished, the soil medium in the discharge area is in a high ionization state, the state cannot be recovered immediately after the current is reduced to zero, the state can be gradually recovered along with the change of time in an exponential law, and the time lasts for tens of milliseconds to hundreds of milliseconds due to the difference of soil characteristic parameters. When the high ionization state is not completely recovered, the subsequent impact current is injected into the soil again, and at the moment, the change of the soil medium parameter in the first impact discharge area inevitably influences the subsequent impact discharge process, and the change of the soil medium parameter corresponds to the calculation process of the subsequent impact discharge parameter, namely the local constraint condition of the model is changed.
In the subsequent impulse discharge process, the soil medium in the newly generated subsequent impulse discharge area is firstly punctured, so that the residual resistivity presented by the soil medium is consistent with the residual resistivity of the first impulse discharge channel firstly punctured calculated in the step two. In the first impulse discharge area and the multi-impulse-channel overlapping area, because of different recovery degrees and different magnitudes of the shunted impulse currents, the residual resistivity presented at the time is unknown, namely the residual resistivity presented by the soil medium during the secondary breakdown discharge in the multi-impulse discharge process, namely the residual resistivity of the soil after the impact discharge.
And fourthly, constructing a subsequent numerical calculation model based on the three-dimensional space structure of the discharge channel, carrying out initialization setting on the subsequent numerical calculation model according to the constraint conditions obtained in the third step, and carrying out subsequent impulse discharge characteristic parameter inversion calculation on the subsequent numerical calculation model after initialization setting to obtain the residual resistivity and the equivalent critical breakdown electric field intensity when the soil medium is subjected to secondary breakdown.
The initialization setting in the fourth step of this embodiment is specifically: setting the resistivity of the subsequent impact discharge area (II) as the first breakdown discharge residual resistivity of the soil calculated in the step 2); the resistivity of the first impact discharge region (r) and the multi-impact channel overlapping region (r) is an unknown variable, and the initial value of the resistivity is also set as the residual resistivity of the soil first breakdown discharge calculated in the step 2).
The inversion calculation of the characteristic parameters of the four-step post-impact discharge in the embodiment specifically comprises the following steps: and taking the subsequent impact current value obtained by the test as excitation, and taking the subsequent impact voltage value as standard response. In the numerical model, iterative inversion calculation is carried out on the resistivity of the first impulse discharge area (r) and the multi-impulse-channel overlapping area (r) from an initial value until the calculated voltage is consistent with the standard response. The soil resistivity in the first region and the third region is calculated, namely the residual resistivity of the soil medium under the corresponding conditions when the soil medium is subjected to secondary breakdown, and the mean value of the electric field intensity in the regions is the equivalent critical breakdown electric field intensity.
And step five, sorting and outputting the soil multi-impact discharge characteristic parameters obtained in the step two and the step four. In this embodiment, the residual resistivity and the critical breakdown strength of the soil obtained by calculation in the second step and the fourth step, and the corresponding soil property and the electrical parameter are recorded together and output for storage.
Example 2
Based on the foregoing embodiment 1, the present embodiment further provides a system for analyzing characteristic parameters of multiple soil impulse discharges, and specifically, as shown in fig. 2, the system of the present embodiment includes a data acquisition module, a three-dimensional module, a first parameter analysis module, a constraint condition module, and a subsequent parameter analysis module.
The data acquisition module of the embodiment is used for acquiring basic data;
the three-dimensional module of the embodiment constructs a three-dimensional space structure of a discharge channel based on basic data;
the first parameter analysis module of the embodiment constructs a first numerical calculation model based on the three-dimensional space structure of the discharge channel, and performs first impulse discharge characteristic parameter inversion calculation through the first numerical calculation model to obtain the residual resistivity of the soil medium impulse discharge and the equivalent critical breakdown electric field intensity under the first impact action;
the constraint condition module of the embodiment judges a multi-impact discharge channel structure and constraint conditions according to the three-dimensional space structure of the discharge channel, and obtains the constraint conditions in the subsequent impact discharge parameter calculation process;
the subsequent parameter analysis module of this embodiment constructs a subsequent numerical calculation model based on the three-dimensional spatial structure of the discharge channel, performs initialization setting on the subsequent numerical calculation model according to the constraint conditions obtained by the constraint condition module, and performs subsequent impulse discharge characteristic parameter inversion calculation through the subsequent numerical calculation model after initialization setting, so as to obtain the residual resistivity and the equivalent critical breakdown electric field strength when the soil medium is secondarily broken down.
The system of the embodiment further comprises an output module, and the output module is used for outputting the soil multiple-impact discharge characteristic parameters obtained by the first-time parameter analysis module and the subsequent parameter analysis module.
Example 3
In this embodiment, the method and the system provided by the above embodiments are applied to specific analysis of soil multi-impact discharge characteristic parameters, and the specific process is as follows:
1. firstly, an object needing calculation is determined, and basic data acquisition is carried out.
Firstly, collecting basic parameters of a discharge environment before impulse current discharge, wherein the size of a discharge sand box in the case is 20 × 20cm in side length, a vertical electrode 1 is a metal cylinder with the length of 10cm and the diameter of 6mm, and the initial soil resistivity rho of a soil medium0Is 213. omega. m.
Collecting electrical parameters, wherein the peak value of the impact current injected into the soil through the vertical electrode 1 is 2kA, the waveform parameter is 8/20 mu s, the peak value of the first impact voltage obtained by collection is 21.1kV, and the peak value of the subsequent impact voltage is 6.4 kV.
The parameters of the discharge channel structure are collected, and the gray scale image of the discharge channel structure is obtained by using an X-ray transmission imaging system, as shown in FIG. 3.
And performing discharge channel image gray scale analysis according to the discharge channel structure gray scale map, and constructing a discharge channel three-dimensional space structure, as shown in fig. 4.
2. And calculating the first impulse discharge characteristic parameters.
Taking the first impulse discharge channel 2 as a research object, taking the subsequent impulse discharge channel 3 as an un-punctured soil medium, and setting parameters consistent with the un-punctured area.
A finite element parameter calculation model is constructed on the basis of the three-dimensional space structure of the discharge channel, and the initial value of the soil resistivity of the first-time impact discharge channel is set to be 213 omega m of the initial soil resistivity. And setting a current source to inject 8/20 mus and 2kA impact current through the vertical electrode X, and calculating the impact voltage on the electrode, wherein the calculated voltage is far higher than the actually measured first impact voltage peak value of 21.1 kV. Therefore, the soil resistivity of the first impulse discharge channel is reduced to 213 x 0.9-191.7 Ω · m, the voltage peak value on the electrode is calculated again, at the moment, the calculated value is still higher than the actually measured value, the steps are continuously repeated to reduce the soil resistivity of the first impulse discharge channel until the calculated voltage peak value of the electrode is consistent with the actually measured voltage peak value, at the moment, the soil resistivity in the first impulse discharge channel is the first breakdown residual resistivity of the soil medium, and the calculated value is 2.40 × 10-4·ρ0. The average value of the electric field intensity in the first impulse discharge channel is calculated to be 187.5 kV/m.
3. And judging the structure of the multi-impact discharge channel and the constraint condition.
According to the three-dimensional space structure judgment of the discharge channel, the discharge channel is a complete branch double-channel structure, and the volumes of the first impact discharge channel and the subsequent impact discharge channel are respectively 54.9cm3And 15.3cm3. The soil in the discharge channel is broken down for the first time after the subsequent impact. The residual soil resistance of the soil should be set to 2.40 × 10-4·ρ0. And the soil medium in the discharge channel is firstly broken down and is not completely recovered, so that the residual resistivity is unknown and is a parameter to be calculated. The initial value of the resistivity of the soil in the first impulse discharge channel is set to be 2.40 multiplied by 10-4·ρ0。
4. And carrying out inversion calculation on the characteristic parameters of the subsequent impulse discharge.
Setting a current source to inject 8/20 mus and 2kA impact current through the vertical electrode 1, and calculating the impact voltage on the electrode, wherein the calculated voltage is far higher than the actually measured subsequent impact voltage peak value of 6.4 kV. Therefore, the resistivity of the soil in the first impulse discharge channel is reduced to be 0.9 times of the current value, the voltage peak value on the electrode is calculated again, if the calculated value is still higher than the actually measured value, the steps are continuously repeated to reduce the resistivity of the soil in the first impulse discharge channel until the calculated voltage peak value of the electrode is consistent with the actually measured voltage peak value, and the apparent resistivity of the calculated first discharge channel under the subsequent impact action is 7.92 multiplied by 10-5·ρ0。
5. And (6) sorting and outputting the result.
The experimental environment is as follows: the side length of the cubic sandbox is 20 cm; the high voltage electrode is 10cm long and 6mm in diameter.
The experimental conditions are as follows: the soil type is sandy soil, the salt content of the soil is 0.1%, the water content of the soil is 6%, and the initial resistivity of the soil is 213 omega m; continuous surge current waveform 8/20 mus, time interval 1ms, current peak 2 kA.
The experimental results are as follows: the peak values of the impulse voltages are respectively 21.1kV at the peak value of the first impulse voltage and 6.4kV at the peak value of the subsequent impulse voltage.
And (3) calculating the result: tested soil medium headResidual resistivity of sub-breakdown is 2.40 × 10-4·ρ0The equivalent critical breakdown field strength is 187.5 kV/m; the residual resistivity of the soil medium after the second breakdown at corresponding time intervals is 7.92 multiplied by 10-5·ρ0。
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A method for analyzing characteristic parameters of soil multiple-impact discharge is characterized by comprising the following steps:
acquiring basic data, and constructing a three-dimensional space structure of a discharge channel based on the basic data;
secondly, constructing a first numerical calculation model based on the three-dimensional space structure of the discharge channel, and performing first impulse discharge characteristic parameter inversion calculation through the first numerical calculation model to obtain the residual resistivity of the soil medium impulse discharge under the first impact action and the equivalent critical breakdown electric field intensity;
judging a multi-impact discharge channel structure and a constraint condition according to the three-dimensional space structure of the discharge channel to obtain the constraint condition in the subsequent impact discharge parameter calculation process;
and fourthly, constructing a subsequent numerical calculation model based on the three-dimensional space structure of the discharge channel, carrying out initialization setting on the subsequent numerical calculation model according to the constraint conditions obtained in the third step, and carrying out subsequent impulse discharge characteristic parameter inversion calculation on the subsequent numerical calculation model after initialization setting to obtain the residual resistivity and the equivalent critical breakdown electric field intensity when the soil medium is subjected to secondary breakdown.
2. The method for analyzing the characteristic parameters of the multiple impact discharges in the soil according to claim 1, wherein the basic data collected in the first step comprises electrical parameters and structural parameters;
the electrical parameters comprise voltage and current waveform parameters on the soil medium in the continuous impulse discharge process and electrical parameters of the soil medium; the electrical parameters are obtained through a grounding system continuous impulse discharge measurement experiment platform;
the structural parameters comprise the actual space structure of the underground discharge channel and the physical structural parameters of the soil discharge environment; the structural parameters are obtained through a soil discharge X-ray projection imaging observation platform.
3. The method for analyzing the soil multiple-impact discharge characteristic parameters as claimed in claim 2, wherein the step one is to construct a three-dimensional space structure of the discharge channel based on the obtained structural parameters.
4. The method for analyzing the characteristic parameters of the multiple times of the soil impulse discharge according to claim 1, wherein the first impulse discharge characteristic parameter inversion calculation in the second step is specifically as follows:
taking a first impact current value obtained by a test as excitation of a first numerical calculation model, and taking an impact voltage value as a standard response;
in the first numerical calculation model, iterative inversion calculation is carried out on the resistivity of the soil in the discharge channel region from an initial value until the calculated voltage is consistent with the standard response, at the moment, the resistivity of the soil in the discharge channel is the residual resistivity of the soil medium impact discharge under the first impact action, and the electric field intensity in the discharge channel is the equivalent critical breakdown electric field intensity.
5. The method for analyzing the characteristic parameters of the multiple impact discharges in the soil according to claim 1, wherein the determination process specifically comprises:
3.1, performing three-dimensional reconstruction of a discharge channel space structure according to the shot three views of the underground discharge channel structure;
3.2, judging the type of a discharge channel based on the reconstructed three-dimensional space structure, and dividing a discharge area;
and 3.3, obtaining constraint conditions in the subsequent impulse discharge parameter calculation process based on the divided discharge areas.
6. The method for analyzing the characteristic parameters of the multiple impact discharges of the soil according to claim 5, wherein the step 3.3 is specifically as follows:
in the process of the first impulse discharge, only the first impulse discharge channel is generated, the subsequent impulse discharge does not occur, and the characteristic parameters of the first impulse discharge are obtained through the second step;
in the subsequent impulse discharge process, the newly generated soil medium in the subsequent impulse discharge area is firstly punctured, so that the residual resistivity presented by the newly generated soil medium is consistent with the residual resistivity of the first punctured impulse discharge channel; at this time, in the first impulse discharge area and the multi-impulse-channel overlapping area, because of different recovery degrees and different magnitudes of the shunted impulse currents, the residual resistivity presented at this time is unknown, that is, the residual resistivity presented when the soil medium is subjected to secondary breakdown discharge in the multi-impulse discharge process, that is, the residual resistivity of the soil after-impulse discharge.
7. The method for analyzing the characteristic parameters of the multiple impact discharges in the soil according to claim 1, wherein the initialization setting in the fourth step is specifically as follows: and setting the resistivity of the subsequent impact discharge area as the residual resistivity of the soil first breakdown discharge obtained in the step two, setting the resistivity of the first impact discharge area and the superposed area of the multiple impact channels as unknown quantity, and setting the initial value as the residual resistivity of the soil first impact discharge obtained in the step two.
8. The method for analyzing the characteristic parameters of the multiple times of the impact discharge of the soil according to claim 1, wherein the inverse calculation of the characteristic parameters of the impact discharge after the four steps is specifically as follows:
taking a subsequent impact current value obtained by the test as excitation, and taking a subsequent impact voltage value as a standard response;
in the subsequent numerical calculation model, iterative inversion calculation is carried out on the resistivity of the first impulse discharge area and the resistivity of the multi-impulse-channel overlapping area from an initial value until the calculated voltage is consistent with the standard response, the calculated soil resistivity of the first impulse discharge area and the multi-impulse-channel overlapping area is the residual resistivity of the soil medium under the corresponding condition when the soil medium is subjected to secondary breakdown, and the mean value of the electric field intensity in the area is the equivalent critical breakdown electric field intensity.
9. The method for analyzing the soil multiple-impact discharge characteristic parameters according to claim 1, further comprising:
and step five, recording the residual resistivity and the critical breakdown strength of the soil obtained by calculation in the step two and the step four, and the corresponding soil property and the electrical parameter together, outputting and storing.
10. A soil multi-impact discharge characteristic parameter analysis system is characterized by comprising a data acquisition module, a three-dimensional module, a first parameter analysis module, a constraint condition module and a subsequent parameter analysis module;
the data acquisition module is used for acquiring basic data;
the three-dimensional module constructs a three-dimensional space structure of the discharge channel based on basic data;
the first parameter analysis module is used for constructing a first numerical calculation model based on the three-dimensional space structure of the discharge channel, and performing first impulse discharge characteristic parameter inversion calculation through the first numerical calculation model to obtain the residual resistivity of the impact discharge of the soil medium under the first impact action and the equivalent critical breakdown electric field intensity;
the constraint condition module judges a multi-impact discharge channel structure and constraint conditions according to the three-dimensional space structure of the discharge channel to obtain the constraint conditions in the subsequent impact discharge parameter calculation process;
the subsequent parameter analysis module constructs a subsequent numerical calculation model based on the three-dimensional space structure of the discharge channel, performs initialization setting on the subsequent numerical calculation model according to the constraint conditions obtained by the constraint condition module, and performs subsequent impulse discharge characteristic parameter inversion calculation through the subsequent numerical calculation model after initialization setting to obtain the residual resistivity and the equivalent critical breakdown electric field intensity when the soil medium is secondarily broken down.
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