Explosion-proof online grounding resistor testing method
By using an inductive loop resistance tester and temperature compensation technology, the problems of measurement errors and safety hazards in grounding systems have been solved, enabling accurate and stable online monitoring of grounding resistance and ensuring safe use in explosion-proof environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU HIGH-TECH ZONE ZHAOQING ELECTRONIC TECHNOLOGY CO LTD
- Filing Date
- 2026-02-27
- Publication Date
- 2026-04-24
AI Technical Summary
Existing technologies cannot fully reflect the overall condition of the grounding system, and are prone to misjudging as qualified due to partial continuity. Furthermore, traditional testing methods require disconnection, which may cause safety hazards. They also do not consider the influence of temperature on grounding resistance measurement, leading to measurement errors.
An inductive loop resistance tester outputs a tiny inductive signal, continuously collects grounding loop data through sensors, and combines this with temperature sensor analysis to analyze the effect of temperature. Non-contact testing and temperature compensation are performed, forming a time series database for trend analysis, enabling online real-time monitoring.
It enables accurate grounding resistance measurement without disconnection in explosion-proof environments, eliminates temperature interference, improves the safety and reliability of testing, and ensures real-time, continuous monitoring and safe operation of the grounding system.
Smart Images
Figure CN121917849A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of resistance testing technology, and more specifically, to a method for testing explosion-proof online grounding resistance. Background Technology
[0002] In flammable and explosive environments such as oil, petrochemical, natural gas, hazardous chemical storage facilities, gas stations, and charging stations, grounding systems are core safety facilities for ensuring safe equipment operation, preventing static electricity buildup, and protecting against explosions or fires caused by lightning strikes. Grounding resistance, a key indicator of the effectiveness of a grounding system, directly reflects the conductivity between the grounding electrode and the earth. Excessive grounding resistance can lead to risks such as the inability to release static electricity in a timely manner, electrified equipment casings, and failure of lightning protection, potentially resulting in major safety accidents. Therefore, real-time and accurate monitoring of grounding resistance in these environments is of irreplaceable importance.
[0003] However, it still has some drawbacks in actual use. For example, the existing grounding resistance test method for hazardous chemical vehicles only tests the resistance value of two local points, which cannot reflect the overall status of the grounding system. It is easy to misjudge the pass due to local continuity, leading to the risk of grounding failure. At the same time, traditional contact test requires disconnecting the grounding connection, which not only affects the normal operation of the vehicle, but may also cause safety hazards in the explosion-proof area due to high voltage output. Traditional online grounding resistance testing methods do not consider the effect of temperature on grounding resistance measurement. For grounding resistance of metallic conductors, temperature differences may lead to large deviations in the measured values, thus interfering with the grounding resistance measurement. Summary of the Invention
[0004] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a method for testing explosion-proof online grounding resistance, which addresses the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for testing explosion-proof online grounding resistance, comprising the following steps: Step S01: Environmental interference detection: The interference data of the tested area is collected by the anti-interference performance testing equipment, the collected data is analyzed to obtain the signal interference intensity index of the tested area, and environmental interference is detected by comparing it with the preset signal interference intensity index threshold.
[0006] Step S02: Induction signal output: Using an induction loop resistance tester, a small induction signal is output to the grounding loop of the area under test, and the parameters of the induction signal are intelligently adjusted based on the environmental interference detection results.
[0007] Step S03: Grounding loop data acquisition: The sensor continuously acquires grounding loop sensing data of each independent test point of m sets of grounding loops each time, and stores the acquired data in the built-in storage module of the tester.
[0008] Step S04: Non-contact inductive grounding resistance test: Based on the sampling data of each group of independent test points in the grounding loop, calculate the resistance measurement value of each independent test point and analyze whether the grounding status of each independent test point is qualified.
[0009] Step S05: Temperature Compensation: This includes a temperature influence analysis sub-step and a temperature compensation sub-step. The temperature influence analysis sub-step collects the ambient temperature of each independent test point in the grounding loop using a temperature sensor and analyzes the change in grounding resistance caused by temperature changes. The temperature compensation sub-step, based on the analysis results of the influence of temperature on resistance, uses a temperature compensation algorithm to reverse-correct the measured resistance value and obtain the temperature compensation value of the grounding resistance at each independent test point after temperature compensation.
[0010] Step S06: Grounding Resistance Value Trend Early Warning: This step is used to obtain the grounding resistance temperature compensation value, ambient temperature, and test time of each independent test point after temperature compensation, forming a time series database. Historical data is then analyzed to monitor the changing trend of grounding resistance.
[0011] Preferably, step S01: environmental interference detection specifically includes: Step S11: Collect interference data of the tested area using an anti-interference performance testing device. The interference data includes signal strength, maximum tolerable signal strength, and background signal strength. The maximum tolerable signal strength is the critical signal strength for normal operation of the device, and the background signal strength is the reference value when there is no interference in the tested area. Step S12: The anti-interference performance testing equipment has a built-in storage module that saves interference data in real time. The collected data is preprocessed, including data cleaning, removal of outliers and duplicate data, normalization of the preprocessed data, and calculation of the signal interference intensity index of the tested area. Step S13: Compare the signal interference intensity index of the measured area with the preset signal interference intensity index threshold. If the signal interference intensity index of the measured area... If the preset signal interference intensity index threshold is high, it indicates that the environmental interference in the measured area is severe, an environmental interference detection report is generated and sent to the management personnel for corresponding anti-interference measures. Conversely, if the threshold is low, it indicates that there is no significant environmental interference in the measured area. When the measured area is found to have no significant environmental interference, subsequent grounding resistance measurements are performed.
[0012] Preferably, step S02: outputting the sensing signal specifically includes: Step S21: Connect the output terminal of the inductive loop resistance tester to each independent test point of the grounding loop through the test cable, and output a small inductive signal to the grounding loop of the area under test; Step S22: Based on the signal interference intensity index of the output of the tested area, send a signal parameter adjustment command to the inductive loop resistance tester to match the current environment.
[0013] Preferably, step S03: grounding loop data acquisition specifically includes: Using the current and voltage sensors equipped in the inductive loop resistance tester, the induced current and induced potential at each independent test point of the grounding loop are continuously collected at a set sampling frequency and marked as follows: , , where i=1,2,...n, i represents the number of the i-th independent test point, and j=1,2,...m, j represents the number of the j-th sample group.
[0014] Preferably, step S04: non-contact inductive grounding resistance test specifically includes: Receive m sets of induced current and induced potential collected from each independent test point, and calculate the loop resistance of each sampled set at each independent test point; Calculate the arithmetic mean of the resistance of all loops at each independent test point as the resistance measurement value of the current grounding loop test point; The resistance measurement values of each independent test point of the grounding loop are obtained and compared with the preset resistance measurement values. If the resistance measurement value of an independent test point is greater than the preset resistance measurement value, it indicates that the grounding status of the grounding loop is unqualified. The current resistance measurement value and timestamp are recorded and an early warning signal is output through the remote monitoring center. Conversely, if the resistance measurement value is less than the preset resistance measurement value, it indicates that the grounding status of the grounding loop is qualified and the tester outputs a qualified signal.
[0015] Preferably, step S05: temperature compensation specifically includes: Temperature effect analysis sub-steps: At each independent test point of the grounding loop, the ambient temperature was collected by a temperature sensor and marked as follows. ; Based on the collected ambient temperature and initial temperature, the preset conductor temperature coefficient and initial conductor resistance value are called to analyze the influence of temperature change on the resistance measurement value and calculate the grounding resistance change of each independent test point under the current ambient temperature. Temperature compensator steps: The grounding resistance measurement value and grounding resistance change of each independent test point are obtained. The resistance measurement value is then reversed by a temperature compensation algorithm to obtain the temperature compensation value of the grounding resistance of each independent test point after temperature compensation.
[0016] Preferably, step S06: grounding resistance value trend early warning specifically includes: After temperature compensation, the grounding resistance temperature compensation value, ambient temperature, and test time of each independent test point are obtained to form a time series database. Calculate the average of the most recent N grounding resistance temperature compensation values to determine whether the current grounding resistance temperature compensation value deviates from the normal range: If |current grounding resistance temperature compensation value - average value of the last N times| is greater than the allowable difference, it indicates that the current grounding resistance temperature compensation value is too high, triggering an instantaneous abnormal alarm, and an alarm signal is output through the remote monitoring center.
[0017] A test method for explosion-proof online grounding resistance includes the following steps: Step S1: Set up double grounding stakes and connect the down conductors of the double grounding stakes through an equipotential bonding line to form a closed-loop test circuit through natural earth connection; Step S2: Using the clamp method, inject a dual-frequency micro-current test signal, including low-frequency and high-frequency components, into the equipotential connection line in a non-contact manner; The clamp method test uses micro-current signals for the test voltage and current, which meets the intrinsically safe explosion-proof standard. In the dual-frequency microcurrent test signal, which includes low-frequency and high-frequency components, the low-frequency component has a frequency range of 0.1 Hz to 10 Hz and is used to characterize the steady-state resistance of the grounding pile in contact with deep soil; the high-frequency component has a frequency range of 1 kHz to 100 kHz and is sensitive to the transient conductive bridge formed on the soil surface due to the deliquescence of the salt film. Step S3: By detecting the voltage response signal and current response signal in response to the dual-frequency micro-current test signal in the closed-loop test circuit, perform frequency domain analysis or filtering on the voltage response signal and current response signal to extract the low-frequency response signal and high-frequency response signal. Based on the low-frequency response signal and the high-frequency response signal, obtain the low-frequency impedance sequence and the high-frequency impedance sequence arranged in time sequence; As an explanation, each data point in the low-frequency impedance sequence and the high-frequency impedance sequence is a resistance value directly calculated by performing effective value calculation and possible phase analysis on the voltage response signal and current response signal within a time window near that moment. The unit is ohms. Because each point in the low-frequency impedance sequence and the high-frequency impedance sequence is itself a resistance value, these values can be directly filtered and outlier removed to finally obtain the steady-state baseline resistance value representing the state of the grounding pile.
[0018] Step S4: Based on the low-frequency impedance sequence and the high-frequency impedance sequence, obtain the steady-state baseline and the salt bridge conductivity coefficient; determine whether a pulse event has occurred based on the steady-state baseline and the salt bridge conductivity coefficient. Step S5: When a pulse event occurs, generate a pulse stress index based on the pulse event. Based on the steady-state baseline and the pulse stress index, the steady-state baseline is compared to determine whether it meets a first preset threshold to determine whether the grounding resistance meets the safety standard; the pulse stress index is compared to determine whether it meets a second preset threshold to quantify the corrosion risk. When the steady-state baseline meets the first preset threshold and the pulse stress index meets the second preset threshold requirement, the grounding resistance is deemed qualified.
[0019] Preferably, in step S4, based on the low-frequency impedance sequence and the high-frequency impedance sequence, the steady-state baseline and the salt bridge conductivity are obtained as follows: After removing pulse event data points from the low-frequency impedance sequence, the low-frequency impedance sequence is filtered and averaged to obtain the statistical mean of the resistance values as the steady-state baseline. The steady-state baseline is used to reflect the state of the metal conductor of the grounding pile itself. At the same time, the salt bridge conductivity coefficient is obtained by calculating the ratio or difference between the high-frequency impedance and the low-frequency impedance in the same time period. The conductivity coefficient of salt bridges utilizes the characteristics of weak skin effect of high-frequency current and sensitivity to ionic conductive pathways of salt film, while strong skin effect of low-frequency current and better reflection of overall soil resistance, thereby quantifying the contribution of temporary conductive bridges formed by soil deliquescent salt film. The pulse event data point is the data point in the low-frequency impedance sequence whose value exceeds the upper limit of the preset range; To determine whether a pulse event has occurred, follow these steps: When the conductivity of the salt bridge exceeds a preset threshold, it is determined that a pulse event has occurred; The data points in the low-frequency impedance sequence and the high-frequency impedance sequence are compared with the steady-state baseline. If the difference between the data point and the steady-state baseline is greater than a preset threshold, it is determined that a pulse event has occurred. Preferably, in step S5, if the conductivity coefficient of the salt bridge exceeds a preset threshold when a pulse event occurs, the conductivity coefficient of the salt bridge is used as the pulse stress index. If the difference between the data point and the steady-state baseline is greater than the preset threshold, the duration of the pulse event is obtained. The product of the difference between the data point and the steady-state baseline and the duration is taken as the energy of a single event. All single event energies within a preset unit time are counted. The pulse stress index is obtained by accumulating all single event energies within a preset unit time. If the conductivity of the salt bridge exceeds the preset threshold and the difference between the data point and the steady-state baseline is greater than the preset threshold, then the pulse stress index with the largest value is taken as the final pulse stress index. When the energy of a single event is the product of the difference between the data point and the steady-state baseline and the duration, the difference between the data point and the steady-state baseline and the duration are multiplied by the numerical values after removing the units. The technical effects and advantages of this invention are as follows: 1. This invention provides a test method for explosion-proof online grounding resistance. Interference data of the tested area is collected using an anti-interference performance testing device. The collected data is analyzed to obtain the signal interference intensity index of the tested area. Environmental interference is detected by comparing the index with a preset threshold. When the tested area is found to have no significant environmental interference, subsequent grounding resistance measurement is performed. Through comprehensive and real-time environmental interference detection, interference factors can be identified and quantified in advance, ensuring accurate subsequent grounding resistance measurement and effectively avoiding measurement errors caused by environmental interference. Using an inductive loop resistance tester, a small inductive signal is output to the grounding loop of the area under test. The current and voltage sensors equipped with the inductive loop resistance tester continuously collect the induced current and induced potential of each independent test point of the grounding loop at a set sampling frequency. Based on the sampling data of each independent test point of the grounding loop, the resistance measurement value of each independent test point is calculated, and the grounding status of each independent test point is analyzed to determine whether it is qualified. The non-contact inductive testing method does not require disconnecting the grounding connection and can be used for online testing while the equipment is running normally, which facilitates the real-time evaluation of the grounding resistance of the area under test. The inductive signal output method not only ensures safe use in explosion-proof environments, but also allows for signal optimization according to actual conditions, improving the accuracy and reliability of the test. 2. This invention provides a method for testing explosion-proof online grounding resistance. Through a temperature influence analysis sub-step, the ambient temperature of each independent test point in the grounding loop is collected using a temperature sensor. The change in grounding resistance caused by temperature variations is analyzed. In a temperature compensation sub-step, based on the analysis results of the temperature influence on resistance, a temperature compensation algorithm is used to reverse-correct the measured resistance values, resulting in temperature-compensated grounding resistance values for each independent test point. Through precise temperature measurement and a scientific compensation algorithm, the interference of temperature factors on the measurement results can be eliminated, improving the stability of the test results. The temperature-compensated grounding resistance values, ambient temperature, and test time for each independent test point after temperature compensation are obtained to form a time-series database. Trend analysis of historical data is performed to monitor the changing trend of grounding resistance, enabling alarms for abnormal grounding resistance trends and ensuring the safe operation of the grounding monitoring system.
[0020] 3. This application employs a clamp-on method and non-contact testing, and because it uses a micro-current, it fundamentally eliminates the possibility of generating electric sparks, fully meeting intrinsic safety and explosion-proof standards. It can be directly applied to online monitoring in hazardous chemical environments. The testing process does not require disconnecting the protected equipment from the grounding stake, enabling real-time and continuous monitoring of the equipment's grounding status, greatly improving the level of safety assurance. The application uses a dual-grounding stake series testing mode, where the measured resistance value is the sum of the resistance values at both grounding points. Poor grounding at either point will result in an unqualified test result, thus enhancing monitoring reliability. Attached Figure Description
[0021] Figure 1 This is a schematic flowchart of an embodiment of the test method for explosion-proof online grounding resistance of the present invention; Figure 2 This is a schematic flowchart of a second embodiment of the test method for explosion-proof online grounding resistance of the present invention. Detailed Implementation
[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] Example 1 Please see Figure 1 As shown, this invention provides a test method for explosion-proof online grounding resistance, comprising the following steps: Step S01: Environmental interference detection: The interference data of the tested area is collected by the anti-interference performance detection equipment, the collected data is analyzed to obtain the signal interference intensity index of the tested area, and environmental interference detection is performed by comparing it with the preset signal interference intensity index threshold.
[0024] In one possible design, step S01: environmental interference detection specifically includes: Step S11: Collect interference data of the tested area using an anti-interference performance testing device. The interference data includes signal strength, maximum tolerable signal strength, and background signal strength. The maximum tolerable signal strength is the critical signal strength for normal operation of the device, and the background signal strength is the reference value when there is no interference in the tested area. Step S12: The anti-interference performance testing equipment has a built-in storage module that saves interference data in real time. The collected data is preprocessed, including data cleaning, removal of outliers and duplicate data, normalization of the preprocessed data, and calculation of the signal interference intensity index of the tested area. Step S13: Compare the signal interference intensity index of the measured area with the preset signal interference intensity index threshold. If the signal interference intensity index of the measured area... If the preset signal interference intensity index threshold is high, it indicates that the environmental interference in the measured area is severe, an environmental interference detection report is generated and sent to the management personnel for corresponding anti-interference measures. Conversely, if the threshold is low, it indicates that there is no significant environmental interference in the measured area. When the measured area is found to have no significant environmental interference, subsequent grounding resistance measurements are performed.
[0025] In this embodiment, it should be specifically noted that the formula for calculating the signal interference intensity index of the measured area is as follows: in, Represented as the signal interference intensity index, Represented as signal strength, Represented as background signal strength, This represents the maximum tolerated signal strength.
[0026] Step S02: Induction signal output: Using an inductive loop resistance tester, a small induction signal is output to the grounding loop of the area under test, and the parameters of the induction signal are intelligently adjusted based on the environmental interference detection results.
[0027] In one possible design, step S02: outputting the sensing signal specifically means: Step S21: Connect the output terminal of the inductive loop resistance tester to each independent test point of the grounding loop through the test cable, and output a small inductive signal to the grounding loop of the area under test; Step S22: Based on the signal interference intensity index of the output of the tested area, send a signal parameter adjustment command to the inductive loop resistance tester to match the current environment.
[0028] Step S03: Grounding loop data acquisition: The grounding loop sensing data of each independent test point of m sets of grounding loops is continuously acquired by the sensor each time, and the acquired data is stored in the built-in storage module of the tester.
[0029] In one possible design, step S03: grounding loop data acquisition specifically includes: Using the current and voltage sensors equipped in the inductive loop resistance tester, the induced current and induced potential at each independent test point of the grounding loop are continuously collected at a set sampling frequency and marked as follows: , , where i=1,2,...n, i represents the number of the i-th independent test point, j=1,2,...m, j represents the number of the j-th sample group; In this embodiment, it should be specifically noted that the tester supports multiple data transmission methods such as RS485 and wireless communication, and can transmit data to a remote monitoring center in real time.
[0030] Step S04: Non-contact inductive grounding resistance test: Used to receive the data transmitted in the grounding loop data acquisition step, calculate the resistance measurement value of each independent test point based on the sampling data of each group of independent test points in the grounding loop, and analyze whether the grounding status of each independent test point is qualified.
[0031] In one possible design, step S04: non-contact inductive grounding resistance test specifically includes: Receive m sets of induced current and induced potential collected from each independent test point, and calculate the loop resistance of each sampled set at each independent test point; Calculate the arithmetic mean of the resistance of all loops at each independent test point as the resistance measurement value of the current grounding loop test point; The resistance measurement values of each independent test point of the grounding loop are obtained and compared with the preset resistance measurement values. If the resistance measurement value of an independent test point is greater than the preset resistance measurement value, it indicates that the grounding status of the grounding loop is unqualified. The current resistance measurement value and timestamp are recorded and an early warning signal is output through the remote monitoring center. Conversely, if the resistance measurement value is less than the preset resistance measurement value, it indicates that the grounding status of the grounding loop is qualified and the tester outputs a qualified signal.
[0032] In this embodiment, it should be specifically noted that the calculation formula for the loop resistance of each group of samples at each independent test point is as follows: ,in, Let be the loop resistance of the j-th sampled group at the i-th independent test point. Let be the induced current sampled at the i-th independent test point in the j-th group. It represents the induced potential of the j-th sample at the i-th independent test point; The formula for calculating the resistance measurement value of the current grounding loop test point is as follows: ,in, Let m represent the resistance measurement value of the i-th independent test point, and m represent the number of sampling groups.
[0033] Step S05: Temperature Compensation: This includes a temperature influence analysis sub-step and a temperature compensation sub-step. The temperature influence analysis sub-step collects the ambient temperature of each independent test point in the grounding loop using a temperature sensor and analyzes the change in grounding resistance caused by temperature changes. The temperature compensation sub-step, based on the analysis results of the influence of temperature on resistance, uses a temperature compensation algorithm to reverse-correct the measured resistance value and obtain the temperature compensation value of the grounding resistance at each independent test point after temperature compensation.
[0034] In one possible design, step S05: temperature compensation specifically includes: Temperature effect analysis sub-steps: At each independent test point of the grounding loop, the ambient temperature was collected by a temperature sensor and marked as follows. ; Based on the collected ambient temperature and initial temperature, the preset conductor temperature coefficient and initial conductor resistance value are called to analyze the influence of temperature change on the resistance measurement value and calculate the grounding resistance change of each independent test point under the current ambient temperature. Temperature compensator steps: The grounding resistance measurement value and grounding resistance change of each independent test point are obtained. The resistance measurement value is then reversed by a temperature compensation algorithm to obtain the temperature compensation value of the grounding resistance of each independent test point after temperature compensation.
[0035] In this embodiment, it should be specifically noted that the formula for calculating the change in grounding resistance at each independent test point under the current ambient temperature is as follows: in, This is expressed as the change in grounding resistance at the i-th independent test point under the current ambient temperature. This is represented as the initial resistance value. Represented as initial temperature, Let represent the ambient temperature at the i-th independent test point. Expressed as the conductor temperature coefficient; The present invention provides another specific embodiment, as follows: The resistance of different metallic conductors changes with temperature in different ways. The temperature coefficients of commonly used grounding materials (such as copper and steel) are as follows: Copper: 0.00393 / ℃ Steel: 0.0045 / ℃ If the grounding conductor is made of copper, and the initial resistance is 1Ω at an initial temperature of 20℃, then if the temperature rises to 40℃, the change in grounding resistance at each independent test point is: =1×0.00393×(40-20)=0.0786Ω; that is, a 20℃ increase in temperature leads to a 7.86% increase in resistance, and the resistance measurement value is further corrected through a temperature compensation sub-step.
[0036] In this embodiment, it should be specifically explained that the temperature compensation algorithm is as follows: Obtain the measured grounding resistance value and the grounding resistance change at each independent test point. Calculate the temperature compensation value of the grounding resistance based on the temperature compensation algorithm. The calculation formula is as follows: in, This represents the temperature-compensated grounding resistance value at each independent test point after temperature compensation. This represents the resistance measurement value at the i-th independent test point. This represents the change in grounding resistance at the i-th independent test point under the current ambient temperature.
[0037] Step S06: Grounding resistance value trend early warning: This is used to obtain the grounding resistance temperature compensation value, ambient temperature, and test time of each independent test point after temperature compensation, form a time series database, perform trend analysis on historical data, and monitor the changing trend of grounding resistance.
[0038] In one possible design, step S06: grounding resistance value trend early warning specifically includes: After temperature compensation, the grounding resistance temperature compensation value, ambient temperature, and test time of each independent test point are obtained to form a time series database. Calculate the average of the most recent N grounding resistance temperature compensation values to determine whether the current grounding resistance temperature compensation value deviates from the normal range: If |current grounding resistance temperature compensation value - average value of the last N times| is greater than the allowable difference, it indicates that the current grounding resistance temperature compensation value is too high, triggering an instantaneous abnormal alarm, and an alarm signal is output through the remote monitoring center.
[0039] In this embodiment, it should be specifically explained that the present invention collects interference data of the tested area through an anti-interference performance testing device, analyzes the collected data to obtain the signal interference intensity index of the tested area, and performs environmental interference detection by comparing it with a preset signal interference intensity index threshold. When the tested area is found to be free of significant environmental interference, subsequent grounding resistance measurement is performed. Through comprehensive and real-time environmental interference detection, interference factors can be identified and quantified in advance, providing a guarantee for accurate subsequent grounding resistance measurement and effectively avoiding measurement errors caused by environmental interference. Using an inductive loop resistance tester, a small inductive signal is output to the grounding loop of the area under test. The current and voltage sensors equipped with the inductive loop resistance tester continuously collect the induced current and induced potential of each independent test point of the grounding loop at a set sampling frequency. Based on the sampling data of each independent test point of the grounding loop, the resistance measurement value of each independent test point is calculated, and the grounding status of each independent test point is analyzed to determine whether it is qualified. The non-contact inductive testing method does not require disconnecting the grounding connection and can be used for online testing while the equipment is running normally, which facilitates the real-time evaluation of the grounding resistance of the area under test. The inductive signal output method not only ensures safe use in explosion-proof environments, but also allows for signal optimization according to actual conditions, improving the accuracy and reliability of the test. This invention employs a temperature influence analysis sub-step to collect the ambient temperature at each independent test point of the grounding loop using a temperature sensor, analyzing the change in grounding resistance caused by temperature variations. A temperature compensation sub-step then uses this analysis to reverse-correct the resistance measurements using a temperature compensation algorithm, resulting in a temperature-compensated grounding resistance value for each independent test point. Through precise temperature measurement and a scientific compensation algorithm, the interference of temperature factors on the measurement results can be eliminated, improving the stability of the test results. The invention acquires the temperature-compensated grounding resistance value, ambient temperature, and test time for each independent test point, forming a time-series database. Trend analysis of historical data monitors the changing trends of grounding resistance, enabling alarms for abnormal grounding resistance trends and ensuring the safe operation of the grounding monitoring system.
[0040] Example 2 Please see Figure 2 As shown, this invention provides a test method for explosion-proof online grounding resistance, comprising the following steps: Step S1: Set up double grounding stakes and connect the down conductors of the double grounding stakes through an equipotential bonding line to form a closed-loop test circuit through natural earth connection; Step S2: Using the clamp method, inject a dual-frequency micro-current test signal, including low-frequency and high-frequency components, into the equipotential connection line in a non-contact manner; The clamp method test uses micro-current signals for the test voltage and current, which meets the intrinsically safe explosion-proof standard. In the dual-frequency microcurrent test signal, which includes low-frequency and high-frequency components, the low-frequency component has a frequency range of 0.1 Hz to 10 Hz and is used to characterize the steady-state resistance of the grounding pile in contact with deep soil; the high-frequency component has a frequency range of 1 kHz to 100 kHz and is sensitive to the transient conductive bridge formed on the soil surface due to the deliquescence of the salt film. Step S3: By detecting the voltage response signal and current response signal in response to the dual-frequency micro-current test signal in the closed-loop test circuit, perform frequency domain analysis or filtering on the voltage response signal and current response signal to extract the low-frequency response signal and high-frequency response signal. Based on the low-frequency response signal and the high-frequency response signal, obtain the low-frequency impedance sequence and the high-frequency impedance sequence arranged in time sequence; As an explanation, each data point in the low-frequency impedance sequence and the high-frequency impedance sequence is a resistance value directly calculated by performing effective value calculation and possible phase analysis on the voltage response signal and current response signal within a time window near that moment. The unit is ohms. Because each point in the low-frequency impedance sequence and the high-frequency impedance sequence is itself a resistance value, these values can be directly filtered and outlier removed to finally obtain the steady-state baseline resistance value representing the state of the grounding pile.
[0041] Step S4: Based on the low-frequency impedance sequence and the high-frequency impedance sequence, obtain the steady-state baseline and the salt bridge conductivity coefficient; determine whether a pulse event has occurred based on the steady-state baseline and the salt bridge conductivity coefficient. Step S5: When a pulse event occurs, generate a pulse stress index based on the pulse event. Based on the steady-state baseline and the pulse stress index, the steady-state baseline is compared to determine whether it meets a first preset threshold to determine whether the grounding resistance meets the safety standard; the pulse stress index is compared to determine whether it meets a second preset threshold to quantify the corrosion risk. When the steady-state baseline meets the first preset threshold and the pulse stress index meets the second preset threshold requirement, the grounding resistance is deemed qualified.
[0042] In one possible design, in step S4, based on the low-frequency impedance sequence and the high-frequency impedance sequence, the steady-state baseline and the salt bridge conductivity are obtained as follows: After removing pulse event data points from the low-frequency impedance sequence, the low-frequency impedance sequence is filtered and averaged to obtain the statistical mean of the resistance values as the steady-state baseline. The steady-state baseline is used to reflect the state of the metal conductor of the grounding pile itself. At the same time, the salt bridge conductivity coefficient is obtained by calculating the ratio or difference between the high-frequency impedance and the low-frequency impedance in the same time period. The conductivity coefficient of salt bridges utilizes the characteristics of weak skin effect of high-frequency current and sensitivity to ionic conductive pathways of salt film, while strong skin effect of low-frequency current and better reflection of overall soil resistance, thereby quantifying the contribution of temporary conductive bridges formed by soil deliquescent salt film. The pulse event data point is the data point in the low-frequency impedance sequence whose value exceeds the upper limit of the preset range; To determine whether a pulse event has occurred, follow these steps: When the conductivity of the salt bridge exceeds a preset threshold, it is determined that a pulse event has occurred; The data points in the low-frequency impedance sequence and the high-frequency impedance sequence are compared with the steady-state baseline. If the difference between the data point and the steady-state baseline is greater than a preset threshold, it is determined that a pulse event has occurred. In one possible design, in step S5, if the salt bridge conductivity exceeds a preset threshold when a pulse event occurs, the salt bridge conductivity is used as the pulse stress index. If the difference between the data point and the steady-state baseline is greater than the preset threshold, the duration of the pulse event is obtained. The product of the difference between the data point and the steady-state baseline and the duration is taken as the energy of a single event. All single event energies within a preset unit time are counted. The pulse stress index is obtained by accumulating all single event energies within a preset unit time. If the conductivity of the salt bridge exceeds the preset threshold and the difference between the data point and the steady-state baseline is greater than the preset threshold, then the pulse stress index with the largest value is taken as the final pulse stress index. When the energy of a single event is the product of the difference between the data point and the steady-state baseline and the duration, the difference between the data point and the steady-state baseline and the duration are multiplied by the numerical values after removing the units. The test method of this application is performed online in a hazardous chemical industry environment, and there is no need to disconnect the electrical connection with the protected object during the test.
[0043] This application employs a clamp-on method and non-contact testing, and due to the use of micro-currents, it fundamentally eliminates the possibility of electrical sparks, fully meeting intrinsically safe explosion-proof standards. It can be directly applied to online monitoring in hazardous chemical environments. The testing process does not require disconnecting the protected equipment from the grounding stake, enabling real-time and continuous monitoring of the equipment's grounding status, greatly improving the level of safety. It uses a dual-grounding stake series testing mode, and the measured resistance value is the sum of the resistance values at both grounding points. Poor grounding at either point will result in an unqualified test result, thus enhancing reliability and providing monitoring assurance.
[0044] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for testing explosion-proof online grounding resistance, characterized in that, Includes the following steps: Step S01: Environmental interference detection: The interference data of the tested area is collected by the anti-interference performance testing equipment, the collected data is analyzed to obtain the signal interference intensity index of the tested area, and environmental interference is detected by comparing it with the preset signal interference intensity index threshold. Step S02: Induction signal output: Using an induction loop resistance tester, a small induction signal is output to the grounding loop of the area under test, and the parameters of the induction signal are intelligently adjusted based on the environmental interference detection results; Step S03: Grounding loop data acquisition: The grounding loop sensing data of each independent test point of m sets of grounding loops is continuously acquired by the sensor each time, and the acquired data is stored in the built-in storage module of the tester; Step S04: Non-contact inductive grounding resistance test: Based on the sampling data of each group of independent test points in the grounding loop, calculate the resistance measurement value of each independent test point and analyze whether the grounding status of each independent test point is qualified. Step S05: Temperature Compensation: This includes a temperature influence analysis sub-step and a temperature compensation sub-step. The temperature influence analysis sub-step collects the ambient temperature of each independent test point of the grounding loop through a temperature sensor and analyzes the change in grounding resistance caused by temperature changes. The temperature compensation sub-step, based on the analysis results of the influence of temperature on resistance, uses a temperature compensation algorithm to reverse the resistance measurement value and obtain the temperature compensation value of the grounding resistance of each independent test point after temperature compensation. Step S06: Grounding Resistance Value Trend Early Warning: This step is used to obtain the grounding resistance temperature compensation value, ambient temperature, and test time of each independent test point after temperature compensation, forming a time series database. Historical data is then analyzed to monitor the changing trend of grounding resistance.
2. The test method for explosion-proof online grounding resistance according to claim 1, characterized in that: Step S01: Environmental interference detection specifically includes: Step S11: Collect interference data of the tested area using an anti-interference performance testing device. The interference data includes signal strength, maximum tolerable signal strength, and background signal strength. The maximum tolerable signal strength is the critical signal strength for normal operation of the device, and the background signal strength is the reference value when there is no interference in the tested area. Step S12: The anti-interference performance testing equipment has a built-in storage module that saves interference data in real time. The collected data is preprocessed, including data cleaning, removal of outliers and duplicate data, normalization of the preprocessed data, and calculation of the signal interference intensity index of the tested area. Step S13: Compare the signal interference intensity index of the measured area with the preset signal interference intensity index threshold. If the signal interference intensity index of the measured area... If the preset signal interference intensity index threshold is high, it indicates that the environmental interference in the measured area is severe, an environmental interference detection report is generated and sent to the management personnel for corresponding anti-interference measures. Conversely, if the threshold is low, it indicates that there is no significant environmental interference in the measured area. When the measured area is found to have no significant environmental interference, subsequent grounding resistance measurements are performed.
3. The test method for explosion-proof online grounding resistance according to claim 1, characterized in that: Step S02: The output of the sensing signal specifically includes: Step S21: Connect the output terminal of the inductive loop resistance tester to each independent test point of the grounding loop through the test cable, and output a small inductive signal to the grounding loop of the area under test; Step S22: Based on the signal interference intensity index of the output of the tested area, send a signal parameter adjustment command to the inductive loop resistance tester to match the current environment.
4. The test method for explosion-proof online grounding resistance according to claim 1, characterized in that: Step S03: Grounding loop data acquisition specifically involves: Using the current and voltage sensors equipped in the inductive loop resistance tester, the induced current and induced potential at each independent test point of the grounding loop are continuously collected at a set sampling frequency and marked as follows: , , where i=1,2,...n, i represents the number of the i-th independent test point, and j=1,2,...m, j represents the number of the j-th sample group.
5. The test method for explosion-proof online grounding resistance according to claim 1, characterized in that: Step S04: Non-contact inductive grounding resistance test specifically includes: Receive m sets of induced current and induced potential collected from each independent test point, and calculate the loop resistance of each sampled set at each independent test point; Calculate the arithmetic mean of the resistance of all loops at each independent test point as the resistance measurement value of the current grounding loop test point; The resistance measurement values of each independent test point of the grounding loop are obtained and compared with the preset resistance measurement values. If the resistance measurement value of an independent test point is greater than the preset resistance measurement value, it indicates that the grounding status of the grounding loop is unqualified. The current resistance measurement value and timestamp are recorded and an early warning signal is output through the remote monitoring center. Conversely, if the resistance measurement value is less than the preset resistance measurement value, it indicates that the grounding status of the grounding loop is qualified and the tester outputs a qualified signal.
6. The test method for explosion-proof online grounding resistance according to claim 1, characterized in that: Step S05: Temperature compensation specifically involves: Temperature effect analysis sub-steps: At each independent test point of the grounding loop, the ambient temperature was collected by a temperature sensor and marked as follows. ; Based on the collected ambient temperature and initial temperature, the preset conductor temperature coefficient and initial conductor resistance value are called to analyze the influence of temperature change on the resistance measurement value and calculate the grounding resistance change of each independent test point under the current ambient temperature. Temperature compensator steps: The grounding resistance measurement value and grounding resistance change of each independent test point are obtained. The resistance measurement value is then reversed by a temperature compensation algorithm to obtain the temperature compensation value of the grounding resistance of each independent test point after temperature compensation.
7. The test method for explosion-proof online grounding resistance according to claim 1, characterized in that: Step S06: Grounding resistance value trend early warning specifically includes: After temperature compensation, the grounding resistance temperature compensation value, ambient temperature, and test time of each independent test point are obtained to form a time series database. Calculate the average of the most recent N grounding resistance temperature compensation values to determine whether the current grounding resistance temperature compensation value deviates from the normal range: If |current grounding resistance temperature compensation value - average value of the last N times| is greater than the allowable difference, it indicates that the current grounding resistance temperature compensation value is too high, triggering an instantaneous abnormal alarm, and an alarm signal is output through the remote monitoring center.
8. A test method for explosion-proof online grounding resistance, characterized in that, Includes the following steps: Step S1: Set up double grounding stakes and connect the down conductors of the double grounding stakes through equipotential bonding wires to form a closed-loop test circuit through natural earth connection; Step S2: Inject a dual-frequency microcurrent test signal, including low-frequency and high-frequency components, into the equipotential bonding line using the clamp method; Step S3: By detecting the voltage response signal and current response signal in response to the dual-frequency micro-current test signal in the closed-loop test circuit, frequency domain analysis or filtering is performed on the voltage response signal and current response signal to extract the low-frequency response signal and high-frequency response signal. Based on the low-frequency response signal and the high-frequency response signal, obtain the low-frequency impedance sequence and the high-frequency impedance sequence arranged in time sequence; Step S4: Based on the low-frequency impedance sequence and the high-frequency impedance sequence, obtain the steady-state baseline and the salt bridge conductivity coefficient; Determine whether a pulse event has occurred based on the steady-state baseline and the conductivity of the salt bridge; Step S5: When a pulse event occurs, generate a pulse stress index based on the pulse event. Based on the steady-state baseline and the pulse stress index, compare whether the steady-state baseline meets the first preset threshold and compare whether the pulse stress index meets the second preset threshold. When the steady-state baseline meets the first preset threshold and the pulse stress index meets the second preset threshold requirement, the grounding resistance is deemed qualified.
9. The test method for explosion-proof online grounding resistance according to claim 8, characterized in that: In step S4, based on the low-frequency impedance sequence and the high-frequency impedance sequence, the steady-state baseline and the salt bridge conductivity are obtained as follows: After removing pulse event data points from the low-frequency impedance sequence, the low-frequency impedance sequence is filtered and averaged to obtain the statistical mean of the resistance values as the steady-state baseline. The steady-state baseline is used to reflect the state of the metal conductor of the grounding pile itself. At the same time, the salt bridge conductivity coefficient is obtained by calculating the ratio or difference between the high-frequency impedance and the low-frequency impedance in the same time period. The pulse event data point is the data point in the low-frequency impedance sequence whose value exceeds the upper limit of the preset range; To determine whether a pulse event has occurred, follow these steps: When the conductivity of the salt bridge exceeds a preset threshold, it is determined that a pulse event has occurred; The data points in the low-frequency impedance sequence and the high-frequency impedance sequence are compared with the steady-state baseline. If the difference between the data point and the steady-state baseline is greater than a preset threshold, it is determined that a pulse event has occurred.
10. The method for testing explosion-proof online grounding resistance according to claim 8, characterized in that: In step S5, when a pulse event occurs, if the conductivity coefficient of the salt bridge exceeds a preset threshold, the conductivity coefficient of the salt bridge is used as the pulse stress index. If the difference between the data point and the steady-state baseline is greater than the preset threshold, the duration of the pulse event is obtained. The product of the difference between the data point and the steady-state baseline and the duration is taken as the energy of a single event. All single event energies within a preset unit time are counted. The pulse stress index is obtained by accumulating all single event energies within a preset unit time. If the conductivity of the salt bridge exceeds a preset threshold and the difference between the data point and the steady-state baseline is greater than a preset threshold, then the pulse stress index with the largest value is taken as the final pulse stress index.