Mine explosion-proof and intrinsically safe type leakage test device and grounding network detection method

Abstract

The application provides a mining explosion-proof and intrinsically safe type electric leakage test device and a grounding network detection method, and relates to the technical field of coal mine underground low-voltage electrical safety detection, wherein the device comprises: a shell, a intrinsically safe detection module, a communication module, a test unit and a control and analysis module; wherein the intrinsically safe detection module is used for detecting the grounding resistance of a single low-voltage distribution switch; the test unit is used for adapting the electric leakage test of each grade low-voltage distribution system; and the control and analysis module analyzes the main grounding network state and compares the low-voltage switch time with the pre-configured standard threshold value. The intrinsically safe detection module adopts constant voltage and constant current technology to realize accurate detection of the grounding resistance of a single switch, and through four steps of single detection, network investigation, test verification and data uploading early warning, the technical difficulties such as wireless communication in coal mine underground grounding dynamic monitoring, single grounding discrimination and intrinsically safe detection are solved, and the grounding network state is comprehensively controlled and the safety hidden danger is early checked.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical safety testing technology in coal mines, and in particular to a mine-use explosion-proof and intrinsically safe leakage current testing device and grounding network testing method. Background Technology

[0002] Coal mines contain flammable and explosive gases such as methane, and the power supply system is a neutral, ungrounded system, placing extremely high demands on the grounding network for explosion-proof equipment and leakage protection. Existing technologies suffer from three major pain points: First, conventional testing equipment is not explosion-proof or intrinsically safe, making it impossible to measure and test the grounding network resistance in real time to ensure compliance; furthermore, it cannot achieve dynamic grounding monitoring online, making it difficult to assess grounding reliability in real time. Second, the grounding network, composed of multiple switches, is interconnected, making it impossible to individually determine whether the grounding of a single device meets the standards, as the resistance between the casing of a single explosion-proof device and the main grounding electrode should not exceed 2Ω. Third, dynamic detection of leakage current protection cannot meet the requirements of coal mine safety regulations; there is a lack of integrated equipment that combines explosion-proof and intrinsically safe performance, making it impossible to accurately complete leakage current protection actions or guarantee compliance with national time limits. These problems lead to the inability to promptly identify potential hazards in the grounding system, easily triggering safety accidents and seriously threatening the lives of underground workers and production stability. Summary of the Invention

[0003] One of the objectives of this invention is to provide a mine-use explosion-proof and intrinsically safe leakage current testing device and a grounding network detection method to solve the above-mentioned technical problems.

[0004] This invention provides a mine-use explosion-proof and intrinsically safe leakage current testing device, comprising: a shell, an intrinsically safe detection module, a communication module, a testing unit, and a control and analysis module; The intrinsically safe detection module is used to detect the grounding resistance of a single low-voltage distribution switch; the test unit is used to adapt to leakage current tests of low-voltage distribution systems of various levels; the control and analysis module is electrically connected to the intrinsically safe detection module, the communication module, and the test unit respectively, and is used to receive grounding resistance detection data, network detection data and switch action signals, analyze the status of the main grounding network and compare the low-voltage switch time with the pre-configured standard threshold.

[0005] Preferably, the communication module includes: a Sub1G wireless communication module and a WiFi module; wherein, the Sub1G wireless communication module operates in the frequency band of 433MHz-915MHz; the WiFi module supports the 802.11b / g / n protocol and is used for network matching and real-time uploading of detection data.

[0006] Preferably, the mining explosion-proof and intrinsically safe leakage current testing device further includes: a power supply located inside the housing, and a power interface configured on the housing.

[0007] Preferably, the test unit includes: a high-voltage vacuum contactor and at least one leakage current test resistor.

[0008] Preferably, the leakage current test resistor includes: a high-voltage metal film resistor with a power ≥ 50W.

[0009] Preferably, the control and analysis module has a built-in storage unit with a storage capacity of ≥1MB, supporting offline query and historical data tracing.

[0010] This invention also provides a grounding network detection method, using any of the above-mentioned mine-use explosion-proof and intrinsically safe leakage current testing devices, comprising: The intrinsically safe detection module outputs a constant voltage and constant current signal to the grounding electrode of the target low-voltage distribution switch. The feedback signal from the grounding loop is collected, and the grounding resistance is calculated based on Ohm's law. Determine whether it meets the pre-configured standard requirements.

[0011] Preferably, when collecting feedback signals from the grounding loop and calculating the grounding resistance based on Ohm's law, the grounding resistance is calculated by taking the average value of a preset number of collection measurements.

[0012] Preferably, the grounding network detection method further includes: Networking is achieved through communication modules; The detection data of each grounding electrode are collected synchronously and then integrated and analyzed.

[0013] Preferred, integrated analysis includes: The detection data of each grounding electrode are fused using a weighted algorithm, and the weighting coefficients are dynamically adjusted according to the importance of the grounding electrode's location.

[0014] This application has the following beneficial effects: I. Comprehensive detection functions: It integrates functions such as leakage current action time detection, grounding resistance compliance judgment, single / three-phase compatibility, and dynamic detection, covering all the needs of leakage current and grounding safety detection of low-voltage equipment in coal mines. Multiple devices can also be used in rotation.

[0015] II. High safety: The intrinsically safe power supply achieves passive safe operation. The microcomputer system automatically completes parameter comparison, mode switching, data storage and remote transmission, reducing human operation errors, improving testing efficiency and data management level. The automatic backup intrinsically safe power supply can provide more than 1 week of continuous testing.

[0016] III. High level of intelligence: It adopts Sub 1G / LoRA wireless communication technology and WIFI technology RS485 serial port. Through the coordination of MCU, the protocol is integrated to ensure the analysis and uploading of leakage current action time data and grounding resistance network data.

[0017] IV. Strong market adaptability: It can be applied to leakage current testing of all low-voltage equipment in coal mines, grounding resistance inspection of all equipment, and leakage protection verification, meeting the universal needs of underground safety testing, and has broad market application prospects.

[0018] V. Leakage Current Action Test: This test can determine whether the action time meets the leakage current protection standard without relying on the action output of the device under test, thus achieving the purpose of neutral testing.

[0019] VI. Networking: Multiple devices form a self-organizing network through sub-1G wireless communication modules, collect detection data from each grounding electrode and transmit them to each other. Finally, the integrated data is uploaded to the ground monitoring system through the WiFi module of any device, realizing the overall status monitoring of the main grounding network.

[0020] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a mine explosion-proof and intrinsically safe leakage current testing device according to an embodiment of the present invention; Figure 2 This is a three-dimensional view of the appearance of a mine explosion-proof and intrinsically safe leakage current testing device according to an embodiment of the present invention; Figure 3 This is a side view of a mine explosion-proof and intrinsically safe leakage current testing device according to an embodiment of the present invention; Figure 4 This is a side view of a mine explosion-proof and intrinsically safe leakage current testing device according to an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the internal working principle of a mine-use explosion-proof and intrinsically safe leakage current testing device according to an embodiment of the present invention; Figure 6 This is a schematic diagram of network detection in an embodiment of the present invention. Detailed Implementation

[0023] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0024] Example 1: This embodiment of the invention provides a mine-use explosion-proof and intrinsically safe leakage current testing device and a grounding network detection method, such as... Figures 1 to 5 As shown, it includes: housing 1, intrinsically safe detection module 2, communication module 3, test unit 4, and control and analysis module 5; housing 1 is an explosion-proof and intrinsically safe housing, made of Q235 steel plate welded together, with a protection level ≥ IP54, suitable for the flammable and explosive environment of coal mine underground gas. Among them, the intrinsically safe detection module 2 is used to detect the grounding resistance of a single low-voltage distribution switch; the test unit 4 is used to adapt to leakage current tests of low-voltage distribution systems of various levels; the control and analysis module 5 is electrically connected to the intrinsically safe detection module 2, the communication module 3, and the test unit 4 respectively, and is used to receive grounding resistance detection data, network detection data and switch action signals, analyze the status of the main grounding network and compare the low-voltage switch time with the pre-configured standard threshold.

[0025] Intrinsically safe detection module 2 employs constant voltage and constant current closed-loop control technology, providing intrinsically safe voltage and current for detecting the grounding resistance of a single low-voltage distribution switch. The detection accuracy is ≤±0.5Ω, meeting the standard requirement of grounding resistance ≤1Ω. The control and analysis module utilizes an STM32 series microcontroller.

[0026] Communication module 3 includes a Sub-1G wireless communication module and a WiFi module. The Sub-1G wireless communication module operates in the 433MHz-915MHz frequency band, enabling the transmission of grounding electrodes, leakage protection, and action values ​​for multiple devices, with a communication distance ≥500m. The WiFi module supports the 802.11b / g / n protocol and is used for network matching and real-time uploading of detection data. The Sub-1G wireless communication module employs frequency hopping spread spectrum technology, with an anti-interference capability ≥20dB, supporting simultaneous communication by multiple nodes, and a maximum network node count ≥100, achieving convergence of serial port, WiFi, and Sub-1G networks.

[0027] To ensure energy supply to all components within the device, the mining explosion-proof and intrinsically safe leakage current testing device also includes: a power supply housed within the outer casing, with a power interface mounted on casing 1. The power supply utilizes an intrinsically safe power supply (intrinsically safe battery), and the power interface is an A3 power interface. The intrinsically safe power supply enables passive monitoring of the device, allowing it to operate independently without an external power source. The A3 power interface allows for external power connection during extended operation, ensuring continued operation. The chamber also integrates a remote communication module, enabling remote data transmission in conjunction with a microcomputer system.

[0028] Test unit 4 includes a high-voltage vacuum contactor 41 and at least one leakage current test resistor 42. The leakage current test resistor 42 includes resistors with different voltage levels: 127V / 2K, 660V / 11K, 1140V / 20K, and 3300V / 50K, adaptable to leakage current testing of low-voltage power distribution systems at different voltage levels. In addition, voltage is detected by a voltage sensor 43.

[0029] The leakage test resistor 42 includes a high-voltage metal film resistor with a power rating of ≥50W, ensuring stable resistance and accurate test data during the leakage test.

[0030] The control and analysis module 5 has a built-in storage unit with a storage capacity of ≥1MB, supporting offline querying and historical data tracing.

[0031] In addition, a high-voltage wiring cavity 7 is provided inside the housing for configuring high-voltage input terminals; and a grounding resistance detection module 6 is used to detect grounding resistance.

[0032] This invention also provides a grounding network detection method, which utilizes the aforementioned mine explosion-proof and intrinsically safe leakage current testing device, comprising: The intrinsically safe detection module outputs a constant voltage and constant current signal to the grounding electrode of the target low-voltage distribution switch. The feedback signal from the grounding loop is collected, and the grounding resistance is calculated based on Ohm's law. Determine whether it meets the pre-configured standard requirements.

[0033] The above steps are for single-unit grounding detection. The constant voltage and constant current signal is ≤12V and the current is ≤10mA. The standard requirement includes: less than or equal to 1Ω.

[0034] To improve detection accuracy, when collecting feedback signals from the grounding loop and calculating grounding resistance based on Ohm's law, a preset number of measurements are performed and the average value is taken to calculate the grounding resistance. For example, the number of measurements is ≥3, and the interval between each measurement is ≤1s, thereby further improving the accuracy of grounding resistance detection.

[0035] To address the needs of network reconnaissance, grounding network detection methods also include: establishing a network through a communication module; synchronously collecting detection data from each grounding electrode and integrating and analyzing it.

[0036] Multiple devices can automatically complete node discovery and networking through the Sub 1G wireless communication module, synchronously collect detection data of each grounding electrode, avoid data conflicts through time division multiple access technology, and transmit the data to the control and analysis module for integration and analysis to determine the overall grounding reliability of the main grounding network.

[0037] The integrated analysis includes: The detection data of each grounding electrode are fused using a weighted algorithm, and the weighting coefficients are dynamically adjusted according to the importance of the grounding electrode's location.

[0038] In addition, based on the voltage level of the low-voltage power distribution system, the control and analysis module controls the high-voltage vacuum contactor to switch the test resistor with the corresponding resistance value to simulate leakage faults of different degrees. The action time can be accurately detected without detecting the feedback of the leakage protection. The action response time of the low-voltage switch is recorded by a high-precision timing module (timing accuracy ≤1ms) and compared with the ≤30ms threshold specified by the national standard. The control and analysis module uploads the detection results, network status, and action time comparison results to the ground monitoring system via the WiFi module. When the grounding resistance exceeds the standard or the action time is unqualified, the alarm module triggers an early warning.

[0039] In a practical networking example, the specific network topology is illustrated as follows: Figure 6 The diagram shows the connection between underground equipment and testing facilities. The main underground substation 28, mining area substation 29, power distribution point 10, cable junction box 11, coal drill integrated protection device 15, coal mining machine 16, and belt conveyor 17 are the main equipment and circuit connection facilities for underground operations. Cable 26, cable grounding layer 27, connecting wire 12, grounding wire 13, and cable connector 14 are used for line connections. Grounding busbar 21, auxiliary grounding busbar 22, main grounding electrode 23, local grounding electrode 24, and leakage protection auxiliary grounding electrode 25 are all testable locations. The device described in this application is configured at location ① in the diagram for testing.

[0040] Example 2: The present invention provides a mine explosion-proof and intrinsically safe leakage current testing device, comprising: a shell, an intrinsically safe detection module, a communication module, a testing unit, and a control and analysis module; The intrinsically safe detection module is used to detect the grounding resistance of a single low-voltage distribution switch; the test unit is used to adapt to leakage current tests of low-voltage distribution systems of various levels; the control and analysis module is electrically connected to the intrinsically safe detection module, the communication module, and the test unit respectively, and is used to receive grounding resistance detection data, network detection data and switch action signals, analyze the status of the main grounding network and compare the low-voltage switch time with the pre-configured standard threshold.

[0041] This invention also provides a grounding network detection method, which utilizes the aforementioned mine explosion-proof and intrinsically safe leakage current testing device, comprising: The intrinsically safe detection module outputs a constant voltage and constant current signal to the grounding electrode of the target low-voltage distribution switch. The feedback signal from the grounding loop is collected, and the grounding resistance is calculated based on Ohm's law. Determine whether it meets the pre-configured standard requirements.

[0042] To address the needs of network reconnaissance, grounding network detection methods also include: establishing a network through a communication module; synchronously collecting detection data from each grounding electrode and integrating and analyzing it.

[0043] Multiple devices can automatically complete node discovery and networking through the Sub 1G wireless communication module, synchronously collect detection data of each grounding electrode, avoid data conflicts through time division multiple access technology, and transmit the data to the control and analysis module for integration and analysis to determine the overall grounding reliability of the main grounding network.

[0044] The integrated analysis includes: The detection data of each grounding electrode are fused using a weighted algorithm, and the weighting coefficients are dynamically adjusted according to the importance of the grounding electrode's location.

[0045] To further ensure the rationality and effectiveness of the determination of weighting coefficients, the optimization of the weighting coefficient determination steps is as follows: Construct a 3D model of the downhole space; perform finite element segmentation on the 3D model; determine the first correlation coefficient based on the position of the finite element in the 3D model; acquire detection data (combustible gas, oxygen, temperature, humidity, etc.) at various locations in the downhole space; map the detection data to each finite element; extract features from the detection data corresponding to each finite element to obtain multiple first feature parameters; based on the first feature parameters, query a pre-configured library for determining second correlation coefficients to obtain the second correlation coefficients corresponding to each finite element; acquire access data of the downhole space; map the access data to each finite element, and then extract features from the access data corresponding to each finite element to obtain multiple second feature parameters; based on the second feature parameters, query a pre-configured library for determining third correlation coefficients to determine the corresponding third correlation coefficients for each finite element; based on the first, second, and third correlation coefficients, determine the corresponding weighting coefficients using a pre-configured weight lookup table. The first characteristic parameters include: parameters representing the maximum, minimum, and average values ​​of combustible gas content; parameters representing the maximum, minimum, and average values ​​of oxygen content; parameters representing the maximum, minimum, and average values ​​of temperature; and parameters representing the maximum, minimum, and average values ​​of humidity. The second correlation coefficient database is pre-configured, in which the first characteristic parameters and second correlation coefficients are associated one-to-one. When constructing the second correlation coefficient database, the higher and more unstable the combustible gas content, the larger the second correlation coefficient; the higher the temperature, the larger the second correlation coefficient; the higher the oxygen content, the larger the second correlation coefficient; and the lower the humidity, the larger the second correlation coefficient. The third correlation coefficient database is also pre-configured, with the third correlation coefficients corresponding one-to-one with the second characteristic parameters. The second characteristic parameters include: parameters representing the number of devices passing through per unit time; and parameters representing the number of people passing through per unit time. During construction, the more people or devices passing through, the larger the third correlation coefficient.

[0046] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A mine-use explosion-proof and intrinsically safe leakage current testing device, characterized in that, include: The enclosure, intrinsically safe detection module, communication module, test unit, and control and analysis module; Among them, the intrinsically safe detection module is used to detect the grounding resistance of a single low-voltage distribution switch; The test unit is used to adapt to leakage current tests of low-voltage power distribution systems of various levels; the control and analysis module is electrically connected to the intrinsically safe detection module, the communication module, and the test unit respectively, and is used to receive grounding resistance detection data, network detection data and switch action signals, analyze the status of the main grounding network and compare the low-voltage switch time with the pre-configured standard threshold.

2. The mine-use explosion-proof and intrinsically safe leakage current testing device as described in claim 1, characterized in that, The communication module includes a Sub1G wireless communication module and a WiFi module; the Sub1G wireless communication module operates in the 433MHz-915MHz frequency band; the WiFi module supports the 802.11b / g / n protocol and is used for network matching and real-time uploading of detection data.

3. The mine-use explosion-proof and intrinsically safe leakage current testing device as described in claim 1, characterized in that, Also includes: The power supply is located inside the casing, and a power interface is provided on the casing.

4. The mine-use explosion-proof and intrinsically safe leakage current testing device as described in claim 1, characterized in that, The test unit includes: a high-voltage vacuum contactor and at least one leakage current test resistor.

5. The mine-use explosion-proof and intrinsically safe leakage current testing device as described in claim 4, characterized in that, The leakage current test resistors include: high voltage metal film resistors with a power rating of ≥50W.

6. The mine-use explosion-proof and intrinsically safe leakage current testing device as described in claim 1, characterized in that, The control and analysis module has a built-in storage unit with a storage capacity of ≥1MB, supporting offline querying and historical data tracing.

7. A grounding network detection method, using the mine explosion-proof and intrinsically safe leakage current testing device as described in claims 1 to 6, characterized in that, include: The intrinsically safe detection module outputs a constant voltage and constant current signal to the grounding electrode of the target low-voltage distribution switch. The feedback signal from the grounding loop is collected, and the grounding resistance is calculated based on Ohm's law. Determine whether it meets the pre-configured standard requirements.

8. The grounding network detection method as described in claim 7, characterized in that, When collecting feedback signals from the grounding loop and calculating the grounding resistance based on Ohm's law, the grounding resistance is calculated by taking the average value of a preset number of data collection measurements.

9. The grounding network detection method as described in claim 7, characterized in that, Also includes: Networking is achieved through communication modules; The detection data of each grounding electrode are collected synchronously and then integrated and analyzed.

10. The grounding network detection method as described in claim 9, characterized in that, The integrated analysis includes: The detection data of each grounding electrode are fused using a weighted algorithm, and the weighting coefficients are dynamically adjusted according to the importance of the grounding electrode's location.

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