Grounding resistance comprehensive test system and method

Abstract

The invention discloses a ground resistance comprehensive test system and method, and belongs to the field of ground test, and the ground resistance comprehensive test method comprises the steps: determining a test monitoring area of ground resistance, drawing a power grid distribution three-dimensional model on the test monitoring area, and marking each ground point in the test monitoring area; detecting a grounding resistance value on the grounding point, and evaluating whether the grounding resistance value of the grounding end on the grounding point is abnormal or not; and for the grounding point with the abnormal grounding resistance value, calculating the equivalent grounding resistance value of the grounding point according to the soil parameters on the grounding point, and evaluating whether the grounding system on the grounding point is damaged or not. The test system comprises a grounding resistance tester, a wireless data module, a soil parameter acquisition module and a far-end monitoring center. According to the invention, the grounding resistance of the grounding end is tested by using the multi-frequency alternating-current electric signal, so that the test requirements of different grounding systems under various working conditions can be met, and the universality and the practicability are ensured.

Description

Technical Field

[0001] The invention relates to the field of grounding resistance testing, and in particular to a grounding resistance comprehensive testing system and method. Background Art

[0002] As the core parameter for measuring the effectiveness of the grounding system, grounding resistance plays a decisive role in the safe operation of power equipment and the safety of personnel. For large-scale high-voltage substations or areas with complex electrical equipment, regular and effective monitoring of the grounding resistance of various types of equipment is the key to maintaining the safety of equipment power use. Traditional grounding resistance test methods such as the potential drop method and the three-pole method have many defects. The potential drop method is significantly affected by the layout of the test electrodes and stray currents. The distance between the test electrodes needs to be accurately set according to the scale of the grounding system to be tested, and the measurement error is large in an environment with stray currents. The three-pole method has a greatly reduced measurement accuracy in complex grounding networks, especially systems containing multiple grounding electrodes with strong mutual coupling. In addition, the existing test system has relatively single functions, making it difficult to accurately and comprehensively evaluate and analyze the grounding resistance characteristics under various working conditions. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a grounding resistance comprehensive testing system and method, which can accurately test and analyze the grounding resistance of the grounding system in a region, thereby improving the reliability and stability of the test results.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0005] A ground resistance comprehensive test method is provided, which comprises:

[0006] Step S1: determine the test monitoring area of ​​the grounding resistance, draw a three-dimensional model of the power grid distribution in the test monitoring area, establish a three-dimensional coordinate system in the three-dimensional model of the power grid distribution, and mark each grounding point in the test monitoring area in the three-dimensional coordinate system;

[0007] Step S2: Detecting the grounding resistance value at the grounding point by using a grounding resistance tester, obtaining the grounding resistance data at the grounding point after each detection, and evaluating whether the grounding resistance value of the grounding end at the grounding point is abnormal;

[0008] Step S3: For a grounding point with an abnormal grounding resistance value, the equivalent grounding resistance value of the grounding point is calculated according to soil parameters at the grounding point to evaluate whether the grounding system at the grounding point is damaged.

[0009] Further, step S2 includes:

[0010] Step S21: Set the interval period T for testing the grounding resistance at each grounding point, and use the grounding resistance tester to test the grounding resistance value at the grounding point to obtain the grounding resistance data at the grounding point after each test. Where n is the number of the grounding point, t is the number of grounding resistance tests, is the grounding resistance value of grounding point n obtained in the tth grounding resistance test;

[0011] Step S22: Based on the output grounding resistance value Using Historical Ground Resistance Data Evaluating ground resistance value Is it abnormal?

[0012] like It is determined that the grounding resistance value of the grounding point n is abnormal, and step S3 is executed, where α1 is the upper limit coefficient of the abnormal fluctuation of the grounding resistance value;

[0013] like It is determined that the grounding resistance value of the grounding point n is normal.

[0014] Furthermore, in step S21, the ground resistance tester performs a ground resistance test on the grounding point, and the method for calculating the ground resistance of the grounding terminal is:

[0015] Step S211: the AC power module of the ground resistance tester sends a variable frequency AC signal to the ground terminal, and the frequency range of the AC signal is [f1, f2];

[0016] Step S212: using the current detection module and the voltage detection module to detect the current signal and the voltage signal of the ground terminal respectively, and filtering the current signal and the voltage signal. The transfer function H(s) of the filter used in the filtering process is:

[0017]

[0018] Where s is the complex frequency variable of the current signal or voltage signal, ω is the cutoff angular frequency, and N is the order of the filter;

[0019] Step S213: constructing a differential equation of the filtered current signal and voltage signal in a discrete domain;

[0020]

[0021] Where n is the discrete time of the current signal or voltage signal, y[n] is the current signal or voltage signal output at discrete time n, M is the input order of the filter, N is the output order of the filter, k is the delay time of the input signal, and a kis the delay coefficient of the input signal, x[nk] is the contribution of the input delayed signal to the output current signal or voltage signal, l is the delay time of the output signal, b l is the delay coefficient of the output signal, y[nl] is the contribution of the output delayed signal to the output current signal or voltage signal;

[0022] Step S214: After filtering the collected current signal and voltage signal, output the filtered current signal I(v) and voltage signal U(v), where v is the sampling time of the current signal and the voltage signal;

[0023] Step S215: considering the effects of the inductance L and the capacitance C at the ground terminal, the impedance of the ground terminal is calculated when an AC power supply is provided;

[0024]

[0025] Where, f is the sampling frequency of the current signal I(v) and the voltage signal U(v), R f is the resistance of the ground terminal under the sampling frequency f, Z f The ground terminal impedance under the sampling frequency f, j(.) is the imaginary part function of the ground terminal impedance;

[0026] Step S216: Based on the different frequencies f1, f2, ..., f m The impedance of the ground terminal under the condition Establish impedance equations;

[0027]

[0028] Where m is the number of the sampling frequency, is the sampling frequency f m The inductance of the ground terminal under the condition, is the sampling frequency f m The capacitance of the ground terminal under the condition, is the sampling frequency f m The resistance of the ground terminal under the condition, is the sampling frequency f m The current signal when is the sampling frequency f m The voltage signal at

[0029] Step S217: extract all ground terminal resistances under different frequency conditions in the impedance equation group, and screen outliers of the ground terminal resistance to calculate the real resistance of the ground terminal.

[0030]

[0031]

[0032] in, is the remaining ground terminal resistance value after filtering out abnormal ground terminal resistance values, e is the number of the remaining ground terminal resistance values, E is the number of the remaining ground terminal resistance values, R min , R max are the minimum and maximum values ​​of the reference range for screening abnormal values ​​of ground terminal resistance, is the grounding resistance detected historically at grounding point n, a is the number of times the grounding resistance is detected historically at grounding point n, t1 is the number of times the average grounding resistance detected historically is the smallest, and t2 is the number of times the average grounding resistance detected historically is the largest;

[0033] Step S218: Output the calculated actual resistance R of the ground terminal t n , as a ground resistance tester to detect the ground resistance value at the grounding point.

[0034] Further, step S3 includes:

[0035] Step S31: Mark the grounding points with abnormal grounding resistance values ​​in the three-dimensional model of the power grid distribution, and collect soil parameters at the grounding points with abnormal grounding resistance values. The soil parameters include the soil resistivity ρ n , soil moisture content w n and soil temperature b n ;

[0036] Step S32: According to the soil resistivity ρ n Calculate the equivalent grounding resistance R reflected by the soil resistivity at the grounding end ρ , according to the soil moisture content w n Calculate the equivalent grounding resistance R reflected by soil moisture content w , according to soil temperature b n Calculate the equivalent ground resistance R reflected by the soil temperature b ;

[0037] Step S33: Using the ground resistance value R t n Evaluate whether the grounding system at the grounding end is damaged by using the equivalent grounding resistance;

[0038] like It is determined that the grounding system at the grounding end is not damaged, η is the error correction coefficient, (R ρ ,R w ,R b ) max Indicates the maximum value item;

[0039] like It is determined that the grounding system at the grounding end has been damaged and leakage may occur at the grounding point n. The dangerous area around the grounding point n is divided on the three-dimensional model of the power grid distribution, and the coordinates of the grounding point n are sent to the staff.

[0040] Furthermore, the equivalent grounding resistance R ρ The calculation method is:

[0041] When the grounding body inserted into the soil is a cylindrical rod structure;

[0042]

[0043] Wherein, L′ is the length of the grounding body, h is the depth of the grounding body inserted into the soil, d is the diameter of the grounding body, and A is the shape coefficient of the grounding body;

[0044] When the grounding body inserted into the soil is a horizontal flat steel structure;

[0045]

[0046] Wherein, g is the width of the grounding body, and o is the thickness of the grounding body.

[0047] Furthermore, the equivalent grounding resistance R w The calculation method is:

[0048]

[0049] Among them, R0 is the grounding resistance when the soil moisture content is 0, and m is the soil characteristic coefficient.

[0050] Furthermore, the equivalent grounding resistance R b The calculation method is:

[0051]

[0052] Wherein, T0 is the reference temperature of the soil, R1 is the grounding resistance under the reference temperature T0, γ is the temperature fluctuation coefficient, and T1 is the current soil temperature.

[0053] Provided is a ground resistance comprehensive test system for executing the above ground resistance comprehensive test method, comprising: a ground resistance tester, a wireless data module, a soil parameter acquisition module and a remote monitoring center;

[0054] The ground resistance tester includes an AC power supply module, a current detection module and a voltage detection module. The AC power supply module provides AC power to the ground terminal. The current detection module and the voltage detection module are used to detect the current signal and the voltage signal of the ground terminal respectively.

[0055] The soil parameter acquisition module includes a soil resistivity sensor, a soil moisture sensor and a soil temperature sensor, which are used to collect soil parameters of the soil near the grounding point;

[0056] The wireless data module is used to send the soil parameters, current signals and voltage signals collected by the soil parameter collection module and the ground resistance tester to the remote monitoring center;

[0057] The remote monitoring center builds a three-dimensional model of the power grid distribution and uses a data analysis module to analyze soil parameters, current signals, and voltage signals.

[0058] The beneficial effects of the present invention are as follows: the present invention uses a multi-frequency AC signal to test the grounding resistance of the grounding terminal, uses signal filtering and analysis and processing algorithms to reduce interference in the environment of stray currents and noise interference, enhances the anti-interference performance of the test system, takes into account the influence of the inductance and capacitance characteristics in the grounding system, improves the accuracy of grounding resistance calculation, and ensures the stability and reliability of the test results. At the same time, the analysis of abnormal grounding resistance is introduced, referring to the influence of changes in the grounding soil environment on the grounding resistance, which can adapt to the testing requirements of different grounding systems under various working conditions, ensuring versatility and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Flow chart of the comprehensive test method for ground resistance. DETAILED DESCRIPTION

[0060] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0061] like Figure 1 As shown, a comprehensive ground resistance test method includes:

[0062] Step S1: determine the test monitoring area of ​​ground resistance, such as a large-area high-voltage substation, a factory area with complex distribution of power grid equipment, etc., draw a three-dimensional model of the power grid distribution in the test monitoring area, and establish a three-dimensional coordinate system in the three-dimensional model of the power grid distribution, and mark each grounding point in the test monitoring area in the three-dimensional coordinate system;

[0063] Step S2: Use a ground resistance tester to detect the ground resistance value at the ground point, obtain the ground resistance data at the ground point after each detection, and evaluate whether the ground resistance value of the ground end at the ground point is abnormal. Step S2 specifically includes:

[0064] Step S21: Set the interval period T for testing the grounding resistance at each grounding point, and use the grounding resistance tester to test the grounding resistance value at the grounding point to obtain the grounding resistance data at the grounding point after each test. Where n is the number of the grounding point, t is the number of grounding resistance tests, is the grounding resistance value of grounding point n obtained in the tth grounding resistance test;

[0065] In step S21, the ground resistance tester performs a ground resistance test on the grounding point, and calculates the ground resistance of the grounding terminal in the following manner:

[0066] Step S211: the AC power module of the ground resistance tester sends a variable frequency AC signal to the ground terminal, and the frequency range of the AC signal is [f1, f2];

[0067] Step S212: using the current detection module and the voltage detection module to detect the current signal and the voltage signal of the ground terminal respectively, and filtering the current signal and the voltage signal. The transfer function H(s) of the filter used in the filtering process is:

[0068]

[0069] Where s is the complex frequency variable of the current signal or voltage signal, ω is the cutoff angular frequency, and N is the order of the filter;

[0070] Step S213: constructing a differential equation of the filtered current signal and voltage signal in a discrete domain;

[0071]

[0072] Where n is the discrete time of the current signal or voltage signal, y[n] is the current signal or voltage signal output at discrete time n, M is the input order of the filter, N is the output order of the filter, k is the delay time of the input signal, and a k is the delay coefficient of the input signal, x[nk] is the contribution of the input delayed signal to the output current signal or voltage signal, l is the delay time of the output signal, b l is the delay coefficient of the output signal, y[nl] is the contribution of the output delayed signal to the output current signal or voltage signal;

[0073] Step S214: After filtering the collected current signal and voltage signal, output the filtered current signal I(v) and voltage signal U(v), where v is the sampling time of the current signal and the voltage signal;

[0074] Step S215: considering the effects of the inductance L and the capacitance C at the ground terminal, the impedance of the ground terminal is calculated when an AC power supply is provided;

[0075]

[0076] Where, f is the sampling frequency of the current signal I(v) and the voltage signal U(v), R f is the resistance of the ground terminal under the sampling frequency f, Z f The ground terminal impedance under the sampling frequency f condition, j(.) is the imaginary part function of the ground terminal impedance.

[0077] Resistor R f It is the real part of the grounding resistance at the grounding end of the equipment, representing the resistance to the current caused by factors such as conductor resistance and soil resistance in the grounding section, and is the main part of energy loss; inductance L reflects the inductance effect caused by the magnetic field generated by the current change in the grounding end. When AC current passes through the grounding end, a magnetic field will be generated around the grounding electrode. This magnetic field will hinder the current, and its size is related to the rate of change of the current; capacitance C is the capacitance effect caused by the electric field distribution between the grounding electrode and the surrounding soil or other grounded objects.

[0078] Step S216: Based on the different frequencies f1, f2, ..., f m The impedance of the ground terminal under the condition Establish impedance equations;

[0079]

[0080] Where m is the number of the sampling frequency, is the sampling frequency f m The inductance of the ground terminal under the condition, is the sampling frequency f m The capacitance of the ground terminal under the condition, is the sampling frequency f m The resistance of the ground terminal under the condition, is the sampling frequency f m The current signal when is the sampling frequency f m The voltage signal when

[0081] Step S217: extract all ground terminal resistances under different frequency conditions in the impedance equation group, and screen outliers of the ground terminal resistance to calculate the real resistance R of the ground terminal. t n ;

[0082]

[0083]

[0084] in, is the remaining ground terminal resistance value after filtering out abnormal ground terminal resistance values, e is the number of the remaining ground terminal resistance values, E is the number of the remaining ground terminal resistance values, R min , R max are the minimum and maximum values ​​of the reference range for screening abnormal values ​​of ground terminal resistance, is the grounding resistance detected historically at grounding point n, a is the number of times the grounding resistance is detected historically at grounding point n, t1 is the number of times the average grounding resistance detected historically is the smallest, and t2 is the number of times the average grounding resistance detected historically is the largest;

[0085] Step S218: Output the calculated actual resistance of the ground terminal As a ground resistance tester, it detects the ground resistance value at the grounding point.

[0086] Step S22: Based on the output grounding resistance value Using Historical Ground Resistance Data Evaluating ground resistance value Is it abnormal?

[0087]

[0088] It is the upper limit coefficient of the abnormal fluctuation of ground resistance value, generally α1 is [1, 1.1];

[0089] like It is determined that the grounding resistance value of the grounding point n is normal.

[0090] Step S3: For the grounding point with abnormal grounding resistance value, calculate the equivalent grounding resistance value of the grounding point according to the soil parameters at the grounding point, and evaluate whether the grounding system at the grounding point is damaged. Step S3 specifically includes:

[0091] Step S31: Mark the grounding points with abnormal grounding resistance values ​​in the three-dimensional model of the power grid distribution, and collect soil parameters at the grounding points with abnormal grounding resistance values. The soil parameters include the soil resistivity ρ n , soil moisture content w n and soil temperature b n ;

[0092] Step S32: According to the soil resistivity ρ n Calculate the equivalent grounding resistance R reflected by the soil resistivity at the grounding end ρ ;

[0093] When the grounding body inserted into the soil is a cylindrical rod structure;

[0094]

[0095] Wherein, L′ is the length of the grounding body, h is the depth of the grounding body inserted into the soil, d is the diameter of the grounding body, and A is the shape coefficient of the grounding body. Generally, A is [-0.6, 0];

[0096] When the grounding body inserted into the soil is a horizontal flat steel structure;

[0097]

[0098] Wherein, g is the width of the grounding body, and o is the thickness of the grounding body;

[0099] According to the soil moisture content w n Calculate the equivalent grounding resistance R reflected by soil moisture content w ;

[0100]

[0101] Among them, R0 is the grounding resistance when the soil moisture content is 0, and m is the soil characteristic coefficient, which is generally taken as [0.8, 1]. The conductivity of water is relatively good. When the moisture content in the soil increases, it is equivalent to adding a conductive channel in the soil, thereby reducing the resistivity of the soil and thus reducing the grounding resistance.

[0102] According to soil temperature n Calculate the equivalent ground resistance R reflected by the soil temperature b ;

[0103]

[0104] Among them, T0 is the reference temperature of the soil, R1 is the grounding resistance under the reference temperature T0, γ is the temperature fluctuation coefficient, the value range of γ is [0.1, 0.5], and T1 is the current soil temperature. When the temperature rises, the movement of ions in the soil intensifies, the conductivity is enhanced, the soil resistivity decreases, and the grounding resistance also decreases accordingly. Conversely, when the temperature decreases, the movement of ions slows down, the soil resistivity increases, and the grounding resistance increases accordingly; especially when the soil temperature is below 0℃, the water in the soil freezes, which will cause the soil resistivity to increase sharply and the grounding resistance to rise significantly.

[0105] Step S33: Using the ground resistance value Evaluate whether the grounding system at the grounding end is damaged by using the equivalent grounding resistance;

[0106] like It is determined that the grounding system at the grounding end is not damaged, η is the error correction coefficient, (R ρ ,R w ,R b ) max Indicates the maximum value item;

[0107] like It is determined that the grounding system at the grounding end has been damaged and leakage may occur at the grounding point n. The dangerous area around the grounding point n is divided on the three-dimensional model of the power grid distribution, and the coordinates of the grounding point n are sent to the staff.

[0108] A ground resistance comprehensive test system, used to perform the above ground resistance comprehensive test method, comprising: a ground resistance tester, a wireless data module, a soil parameter acquisition module and a remote monitoring center;

[0109] The ground resistance tester includes an AC power supply module, a current detection module and a voltage detection module. The AC power supply module provides AC power to the ground terminal. The current detection module and the voltage detection module are used to detect the current signal and the voltage signal of the ground terminal respectively.

[0110] The soil parameter acquisition module includes a soil resistivity sensor, a soil moisture sensor and a soil temperature sensor, which are used to collect soil parameters of the soil near the grounding point;

[0111] The wireless data module is used to send the soil parameters, current signals and voltage signals collected by the soil parameter collection module and the ground resistance tester to the remote monitoring center;

[0112] The remote monitoring center builds a three-dimensional model of the power grid distribution and uses a data analysis module to analyze soil parameters, current signals, and voltage signals.

[0113] The present invention uses a multi-frequency AC signal to test the grounding resistance of the grounding terminal, and uses signal filtering and analysis processing algorithms to reduce interference in the stray current environment and noise interference, enhance the anti-interference performance of the test system, consider the influence of the inductance and capacitance characteristics in the grounding system, improve the accuracy of the grounding resistance calculation, and ensure the stability and reliability of the test results. At the same time, it also introduces the analysis of abnormal grounding resistance, and refers to the influence of changes in the grounding soil environment on the grounding resistance, which can adapt to the testing needs of different grounding systems under various working conditions, ensuring versatility and practicality.

Claims

1. A ground resistance comprehensive test method, characterized in that: include: Step S1: determine the test monitoring area of ​​the grounding resistance, draw a three-dimensional model of the power grid distribution in the test monitoring area, establish a three-dimensional coordinate system in the three-dimensional model of the power grid distribution, and mark each grounding point in the test monitoring area in the three-dimensional coordinate system; Step S2: Detecting the grounding resistance value at the grounding point by using a grounding resistance tester, obtaining the grounding resistance data at the grounding point after each detection, and evaluating whether the grounding resistance value of the grounding end at the grounding point is abnormal; Step S3: For a grounding point with an abnormal grounding resistance value, the equivalent grounding resistance value of the grounding point is calculated according to soil parameters at the grounding point to evaluate whether the grounding system at the grounding point is damaged.

2. The ground resistance comprehensive testing method according to claim 1 is characterized in that: The step S2 comprises: Step S21: Set the interval period T for testing the grounding resistance at each grounding point, and use the grounding resistance tester to test the grounding resistance value at the grounding point to obtain the grounding resistance data at the grounding point after each test. Where n is the number of the grounding point, t is the number of grounding resistance tests, is the grounding resistance value of grounding point n obtained in the tth grounding resistance test; Step S22: Based on the output grounding resistance value Using Historical Ground Resistance Data Evaluating ground resistance value Is it abnormal? like It is determined that the grounding resistance value of the grounding point n is abnormal, and step S3 is executed, where α1 is the upper limit coefficient of the abnormal fluctuation of the grounding resistance value; like It is determined that the grounding resistance value of the grounding point n is normal.

3. The ground resistance comprehensive testing method according to claim 2 is characterized in that: In step S21, the ground resistance tester performs a ground resistance test on the grounding point, and the method for calculating the ground resistance of the grounding end is: Step S211: the AC power module of the ground resistance tester sends a variable frequency AC signal to the ground terminal, and the frequency range of the AC signal is [f1, f2]; Step S212: using the current detection module and the voltage detection module to detect the current signal and the voltage signal of the ground terminal respectively, and filtering the current signal and the voltage signal. The transfer function H(s) of the filter used in the filtering process is: Where s is the complex frequency variable of the current signal or voltage signal, ω is the cutoff angular frequency, and N is the order of the filter; Step S213: constructing a differential equation of the filtered current signal and voltage signal in a discrete domain; Where n is the discrete time of the current signal or voltage signal, y[n] is the current signal or voltage signal output at discrete time n, M is the input order of the filter, N is the output order of the filter, k is the delay time of the input signal, and a k is the delay coefficient of the input signal, x[nk] is the contribution of the input delayed signal to the output current signal or voltage signal, l is the delay time of the output signal, b l is the delay coefficient of the output signal, y[nl] is the contribution of the output delayed signal to the output current signal or voltage signal; Step S214: After filtering the collected current signal and voltage signal, output the filtered current signal I(v) and voltage signal U(v), where v is the sampling time of the current signal and the voltage signal; Step S215: considering the effects of the inductance L and the capacitance C at the ground terminal, the impedance of the ground terminal is calculated when an AC power supply is provided; Where, f is the sampling frequency of the current signal I(v) and the voltage signal U(v), R f is the resistance of the ground terminal under the sampling frequency f, Z f The ground terminal impedance under the sampling frequency f, j(.) is the imaginary part function of the ground terminal impedance; Step S216: Based on the different frequencies f1, f2, ..., f m The impedance of the ground terminal under the condition Establish impedance equations; Where m is the number of the sampling frequency, is the sampling frequency f m The inductance of the ground terminal under the condition, is the sampling frequency f m The capacitance of the ground terminal under the condition, is the sampling frequency f m The resistance of the ground terminal under the condition, is the sampling frequency f m The current signal when is the sampling frequency f m The voltage signal when Step S217: extract all ground terminal resistances under different frequency conditions in the impedance equation group, and screen outliers of the ground terminal resistance to calculate the real resistance of the ground terminal. in, is the remaining ground terminal resistance value after filtering out abnormal ground terminal resistance values, e is the number of the remaining ground terminal resistance values, E is the number of the remaining ground terminal resistance values, R min , R max are the minimum and maximum values ​​of the reference range for screening abnormal values ​​of ground terminal resistance, is the grounding resistance detected historically at grounding point n, a is the number of times the grounding resistance is detected historically at grounding point n, t1 is the number of times the average grounding resistance detected historically is the smallest, and t2 is the number of times the average grounding resistance detected historically is the largest; Step S218: Output the calculated actual resistance of the ground terminal As a ground resistance tester, it detects the ground resistance value at the grounding point.

4. The ground resistance comprehensive testing method according to claim 3 is characterized in that: The step S3 comprises: Step S31: Mark the grounding points with abnormal grounding resistance values ​​in the three-dimensional model of the power grid distribution, and collect soil parameters at the grounding points with abnormal grounding resistance values. The soil parameters include the soil resistivity ρ n , soil moisture content w n and soil temperature b n ; Step S32: According to the soil resistivity ρ n Calculate the equivalent grounding resistance R reflected by the soil resistivity at the grounding end ρ , according to the soil moisture content w n Calculate the equivalent grounding resistance R reflected by soil moisture content w , according to soil temperature b n Calculate the equivalent ground resistance R reflected by the soil temperature b ; Step S33: Using the ground resistance value Evaluate whether the grounding system at the grounding end is damaged by using the equivalent grounding resistance; like It is determined that the grounding system at the grounding end is not damaged, η is the error correction coefficient, (R ρ ,R w ,R b ) max Indicates the maximum value item; like It is determined that the grounding system at the grounding end has been damaged and leakage may occur at the grounding point n. The dangerous area around the grounding point n is divided on the three-dimensional model of the power grid distribution, and the coordinates of the grounding point n are sent to the staff.

5. The ground resistance comprehensive testing method according to claim 4 is characterized in that: The equivalent grounding resistance R ρ The calculation method is: When the grounding body inserted into the soil is a cylindrical rod structure; Wherein, L′ is the length of the grounding body, h is the depth of the grounding body inserted into the soil, d is the diameter of the grounding body, and A is the shape coefficient of the grounding body; When the grounding body inserted into the soil is a horizontal flat steel structure; Wherein, g is the width of the grounding body, and o is the thickness of the grounding body.

6. The ground resistance comprehensive testing method according to claim 4 is characterized in that: The equivalent grounding resistance R w The calculation method is: Among them, R0 is the grounding resistance when the soil moisture content is 0, and m is the soil characteristic coefficient.

7. The ground resistance comprehensive testing method according to claim 4 is characterized in that: The equivalent grounding resistance R b The calculation method is: Wherein, T0 is the reference temperature of the soil, R1 is the grounding resistance under the reference temperature T0, γ is the temperature fluctuation coefficient, and T1 is the current soil temperature.

8. A ground resistance comprehensive test system, used to execute the ground resistance comprehensive test method according to any one of claims 1 to 7, characterized in that: include: Ground resistance tester, wireless data module, soil parameter acquisition module and remote monitoring center; The ground resistance tester comprises an AC power supply module, a current detection module and a voltage detection module, wherein the AC power supply module provides an AC power supply to the ground terminal, and the current detection module and the voltage detection module are used to detect the current signal and the voltage signal of the ground terminal respectively; The soil parameter acquisition module includes a soil resistivity sensor, a soil moisture sensor and a soil temperature sensor, which are used to collect soil parameters of the soil near the grounding point; The wireless data module is used to send the soil parameters, current signals and voltage signals collected by the soil parameter collection module and the ground resistance tester to a remote monitoring center; The remote monitoring center builds a three-dimensional model of power grid distribution and uses a data analysis module to analyze soil parameters, current signals and voltage signals.

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