Resistance box for electric leakage test
By employing cable shielding and grounding loop carrier communication and snap-fit inductive couplers in the leakage current test resistance box in coal mines, the problems of unstable underground communication and unsafe grounding were solved, thus achieving reliability and safety in leakage current testing.
Patent Information
- Application Number
- CN202520311489.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-25
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2035-02-25
AI Technical Summary
In the underground environment of coal mines, the Ethernet communication coverage of leakage protection devices is insufficient and the power line carrier communication is unstable, which leads to the failure of leakage test, and unreliable grounding may affect personal safety.
The device uses a cable shield and ground wire to form a loop for carrier communication, uses a snap-fit inductive coupler for signal coupling, has a grounding detection function, and is equipped with a supercapacitor bank to ensure that the device can still work normally when the power is off. It automatically selects the test resistor and uploads the test results.
It enables long-distance reliable communication in complex downhole environments, improves the safety and reliability of leakage current testing, reduces the risk of manual operation, and ensures the timely storage and uploading of test results.
Smart Images
Figure CN223756844U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a leakage test resistance box belongs to the field of power system automation. BACKGROUND
[0002] The coal mine underground environment is complex, and there are explosive gas mixtures such as methane and coal dust, and the space is narrow, humid and high temperature, and leakage phenomenon is easy to occur. In order to ensure the safety of the underground power supply system, the leakage protection device needs to be tested regularly to verify its reliability and response speed. The leakage test resistance box realizes remote leakage test by integrating test resistance and using power line carrier or Ethernet communication technology.
[0003] However, in practical application, the coal mine underground loop network may not be fully laid, resulting in that the Ethernet communication cannot be used, and the quality of the power line carrier communication is greatly affected by the line load, especially when there are frequency conversion devices in the line, the power line carrier communication is difficult to guarantee stable and reliable long distance. In addition, the leakage test resistance box needs to connect the test resistance into the auxiliary grounding pole, and the shell needs to be connected to the main grounding pole. If the two ground wires are not reliably connected, it will cause the leakage test to fail, and even affect personal safety. UTILITY MODEL CONTENTS
[0004] The utility model discloses just in view of the prior art existing problem provides a leakage test resistance box, utilizes the loop that constitutes based on cable screen and ground wire to carry out carrier communication, and the communication signal is input through the clamping type inductive coupler, guarantees the reliable communication of long distance, has the ground detection function, and detects the resistance value between the test ground and the shell ground before the test, so as to guarantee the safety of test.
[0005] In order to achieve the above object, the utility model provides a leakage test resistance box, the resistance box includes power module, carrier module, coupler module, resistance module, ground detection module, communication module, man-machine interaction module and CPU module, the power module is used to convert line voltage into whole machine power supply, the carrier module is used for the transceiver processing of carrier signal, the coupler module is used for coupling the carrier signal that the carrier module sends into the loop that constitutes based on cable screen and ground wire and providing the carrier signal that restores after obtaining in the screen layer to the carrier module processing, the resistance module is used for the resistance when leakage test, the ground detection module is used for detecting whether the device ground is reliable, the communication module is used for providing RS485 and ethernet interface, the man-machine interaction module is used for state display and infrared remote control operation processing, the logic processing module is used for information collection and function logic processing.
[0006] As an improvement of the utility model, the power module has a super capacitor group, when external power supply is disconnected, the device can still work continuously for 3 minutes. In the leakage test, the superior switch trips, the resistance box can save the test results in time, and upload the test results;
[0007] The super capacitor group is composed of 10 capacitors of 30F, 2.7V, when the leakage test resistance box is externally powered, the capacitor can be charged in a few seconds; when the external power supply is disconnected, the capacitor discharges rapidly, ensuring the equipment to continue normal work.
[0008] As an improvement of the utility model, the coupler module is an inductive clamping coupler, which is directly clamped on the outer side of the cable without contacting the copper core of the cable.
[0009] The inductive clamping coupler converts the high-frequency voltage signal emitted by the carrier module into a high-frequency current signal, and uses the principle of electromagnetic induction to couple the high-frequency current signal into the loop composed of the cable shielding layer and the ground wire. Other couplers in the loop restore the induced current to a high-frequency voltage signal, which is recognized by other carrier modules.
[0010] As an improvement of the utility model, the resistance module has a total of 4 groups of test resistors, which are automatically put into corresponding test resistors according to different system voltages.
[0011] As an improvement of the utility model, the resistance module has a total of 4 groups of test resistors, which are respectively 20K ohms, 11K ohms, 3.5K ohms and 2K ohms.
[0012] As an improvement of the utility model, the grounding detection module determines whether the device is reliably grounded according to the resistance value between the test ground and the shell ground.
[0013] As an improvement of the utility model, the grounding detection module comprises: a test resistor R1, a test resistor R2, a reference voltage U, the R1 is connected to the positive electrode of U, the R2 is connected to the negative electrode of U, a shell ground GND-2, a test ground GND-1, a test relay node K2, the test resistor R1 and the test resistor R2 are connected in series and connected to the reference voltage U, the negative end of the reference voltage U is connected to the shell ground GND-2, the test ground GND-1 is connected to the position X between R1 and R2 through the test relay node K2.
[0014] As an improvement of the utility model, the test resistor R1 ranges from 100 to 500 ohms.
[0015] As an improvement of the utility model, the test resistor R2 ranges from 100 to 500 ohms.
[0016] As an improvement of the utility model, the reference voltage U is 5V or 3.3V.
[0017] Compared with the prior art, the utility model has the advantages that (1) the cable shielding layer and the ground wire form a loop to transmit the carrier signal, solving the problems of insufficient underground loop network coverage and unstable power line carrier communication; (2) the super capacitor is fast charged and discharged, ensuring reliable storage and uploading of test results after the leakage test; (3) the clamping type inductive coupler does not need to contact the cable copper core during installation, improving construction safety; (4) the leakage test resistance is automatically selected, reducing the risk of mismatch between the manually selected test resistance and voltage grade; and (5) the test grounding end resistance detection function ensures the safety of the leakage test. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 is the device schematic diagram of the utility model. DETAILED DESCRIPTION
[0019] In order to deepen the understanding of the utility model, the following detailed description is made in combination with the drawings.
[0020] Embodiment 1: Referring to Figure 1 A leakage test resistance box, the resistance box comprises a power module, a carrier module, a coupler module, a resistance module, a grounding detection module, a communication module, a man-machine interaction module and a CPU module, the power module is used for converting line voltage into whole machine power supply, the carrier module is used for carrier signal transceiving processing, the coupler module is used for coupling the carrier signal sent by the carrier module into the loop formed by the cable shielding layer and the ground wire and providing the carrier signal obtained in the shielding layer to the carrier module for processing after the carrier signal is restored, the resistance module is used for inputting resistance during the leakage test, the grounding detection module is used for detecting whether the device grounding is reliable, the communication module is used for providing RS485 and Ethernet interface, the man-machine interaction module is used for state display and infrared remote control operation processing, and the logic processing module is used for information collection and function logic processing.
[0021] The power module has a super capacitor group, when external power supply is disconnected, the device can still work for 3 minutes with power supply.
[0022] The super capacitor group is composed of 10 capacitors with 30F and 2.7V, when the leakage test resistance box is powered by the external power supply, the capacitor can be charged in a few seconds; when the external power supply is disconnected, the capacitor is rapidly discharged, ensuring that the equipment continues to work normally.
[0023] The coupler module is an inductive clamping coupler, which is directly clamped on the outside of the cable without contacting the cable copper core.
[0024] The inductive card coupling converter converts the high-frequency voltage signal emitted by the carrier module into a high-frequency current signal, and utilizes electromagnetic induction principle to couple the high-frequency current signal into a loop formed by the cable shielding layer and the ground wire, and other couplers in the loop restore the induced current into a high-frequency voltage signal, so as to be recognized by other carrier modules.
[0025] The resistance module has four groups of test resistances, and the corresponding test resistance is automatically input according to different system voltages.
[0026] As an improvement of the utility model, the resistance module has four groups of test resistances, which are 20K ohms, 11K ohms, 3.5K ohms and 2K ohms respectively.
[0027] The ground detection module determines whether the device is reliably grounded according to the resistance value between the test ground and the shell ground.
[0028] The ground detection module comprises a test resistance R1, a test resistance R2, a reference voltage U, a shell ground GND-2, a test ground GND-1 and a test relay node K2.
[0029] The test resistance R1 and the test resistance R2 are connected in series and connected to the reference voltage U, R1 is connected to the positive electrode of U, R2 is connected to the negative electrode of U, the negative end of the reference voltage U is connected to the shell ground GND-2, and the test ground GND-1 is connected to the X position between R1 and R2 through the test relay node K2.
[0030] The test resistance R1 is 100 ohms.
[0031] The test resistance R2 is 100 ohms.
[0032] The reference voltage U is 3.3V.
[0033] The method for detecting the resistance value between the test ground and the shell ground is as follows:
[0034] 1. When detecting starting, K2 is closed, the resistance Rk and R2 between the test ground and the shell ground are connected in parallel, at this time, the equivalent resistance between the X position and the shell ground is Rx=Rk*R2 / (Rk+R2);
[0035] 3. The voltage at the two ends of R2 is U2=U*Rx / (R1+Rx), that is, U2=U*R2 / (R1*R2 / Rk+R1+R2);
[0036] 4. After arrangement, Rk=R1*R2 / (U*R2 / U2-R1-R2), after R1, R2 and U are brought in, Rk=100 / (3.3 / U2-2) is obtained; more U2 and Rk corresponding values are shown in Table 1
[0037] Table 1 sampling voltage value and test data of resistance value between test ground and shell ground
[0038] Serial number Voltage U2 (V) Resistance Rk (Ohm) 1 0.001 0.030321407 2 0.01 0.304878049 3 0.1 3.225806452 4 1 76.92307692 5 1.5 500
[0039] After the CPU sampling module obtains the U2 voltage value, the corresponding resistance value can be calculated according to the formula, so as to determine whether the test ground and the shell ground are reliably connected.
[0040] It should be noted that the above embodiments are not intended to limit the scope of protection of the present application, and equivalent transformations or substitutions made on the basis of the above technical solutions fall within the scope of protection of the claims of the present application.
Claims
1. An electric leakage test resistance box, characterized by: The resistance box comprises a power module, a carrier wave module, a coupler module, a resistance module, a ground detection module, a communication module, a man-machine interaction module and a CPU module, the power module is used for converting line voltage into whole machine power supply, the carrier wave module is used for transceiving processing of carrier wave signals, the coupler module is used for coupling carrier wave signals emitted by the carrier wave module into a loop composed of a cable shielding layer and a ground wire and providing the carrier wave module with the carrier wave signals obtained from the shielding layer after restoration, the resistance module is used for inputting resistance during a leakage test, the ground detection module is used for detecting whether device grounding is reliable, the communication module is used for providing RS485 and Ethernet interfaces, the man-machine interaction module is used for state display and infrared remote control operation processing, and the logic processing module is used for information collection and function logic processing.
2. The leakage test resistor box according to claim 1, characterized in that, The power module has a super capacitor group, when external power supply is disconnected, the device can still work for 3 minutes; when a superior switch trips during a leakage test, the resistance box can save test results in time and upload the test results; The super capacitor group is composed of 10 capacitors with 30F and 2.7V, when the resistance box is powered by external power supply, the capacitors can be charged in seconds; when the external power supply is disconnected, the capacitors are discharged rapidly to ensure that the device continues to work normally.
3. The leakage test resistor box according to claim 1, wherein The coupler module is an inductive clamping coupler which is directly clamped on the outside of the cable without contacting the copper core of the cable. The inductive clamping coupler converts high-frequency voltage signals emitted by the carrier wave module into high-frequency current signals, and couples the high-frequency current signals into a loop composed of a cable shielding layer and a ground wire by using electromagnetic induction principle, other couplers in the loop restore the induced current into high-frequency voltage signals, so as to be recognized by other carrier wave modules.
4. The leakage test resistor box of claim 1, wherein, The resistance module has a total of 4 groups of test resistors which automatically input corresponding test resistors according to different system voltages. The resistance module has a total of 4 groups of test resistors which are 20K ohms, 11K ohms, 3.5K ohms and 2K ohms respectively.
5. The leakage test resistor box of claim 1, wherein, The ground detection module comprises a test resistor R1, a test resistor R2, a reference voltage U, a shell ground GND-2, a test ground GND-1 and a test relay node K2. The test resistor R1 and the test resistor R2 are connected in series and connected to the reference voltage U, R1 is connected to the positive electrode of U, R2 is connected to the negative electrode of U, the negative end of the reference voltage U is connected to the shell ground GND-2, and the test ground GND-1 is connected to the X position between R1 and R2 through the test relay node K2.
6. The leakage test resistor box of claim 5, wherein, The test resistor R1 ranges from 100 ohms to 500 ohms.
7. The leakage test resistor box of claim 5, wherein, The test resistor R2 ranges from 100 ohms to 500 ohms.
8. The leakage test resistor box of claim 5, wherein, The reference voltage U is 5V or 3.3V.