Explosion-proof intelligent junction box with monitoring function for coal mine

Abstract

The invention provides an explosion-proof intelligent junction box with a monitoring function for a coal mine, which comprises an explosion-proof shell, an explosion-proof upper cover, a power taking binding post, a temperature monitoring binding post and a cable entry device, and is characterized in that the explosion-proof upper cover is provided with an observation window, and a control display unit for displaying cable operation information is mounted in the explosion-proof upper cover; the cable lead-in device is used for sealing and fixing the armored cable and the rubber sleeve cable; the control display unit is an embedded product system formed by a single-chip microcomputer, and is at least used for achieving the functions of voltage and current indication of a high-voltage cable or a low-voltage cable, grounding sheath current detection, partial discharge, arc light and temperature rise monitoring, cavity humidity monitoring, infrared remote control operation and data communication uploading. The explosion-proof junction box can solve the problems that an existing explosion-proof junction box is single in function and cannot monitor the operation condition of a cable in real time, and the electrical safety of an underground coal mine is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of underground coal mine electrical equipment, and in particular to an explosion-proof intelligent junction box with monitoring function for coal mines. Background Art

[0002] Explosion-proof high and low voltage junction boxes in underground coal mines are an essential part of the underground coal mine electrical system. They are mainly used for the connection and branching of cables for signal, lighting, power equipment, etc. These junction boxes play a crucial role in the harsh environment of underground coal mines, ensuring the safe and reliable connection of cables, thus maintaining the stable operation of the entire power supply system.

[0003] However, the existing explosion-proof junction boxes have certain limitations in design. They are mainly designed as simple electrical connection components with relatively single functions, mainly meeting the physical connection and branching needs of cables. However, in actual use, these junction boxes often cannot monitor and warn the operating conditions of cables in real time.

[0004] Specifically, when problems such as a decrease in cable insulation performance, abnormal temperature at the joint, and abnormal humidity inside the explosion-proof cavity occur, the existing explosion-proof junction boxes cannot provide an intuitive basis for judgment. If these problems are not discovered and processed in a timely manner, serious consequences may occur, such as accidentally opening the explosion-proof cover while energized, cable temperature rise and heating, local discharge causing arc flashover until short circuit, and insulation degradation causing single-phase grounding faults. These faults may not only burn out the cables and junction boxes but also pose a serious threat to the safe operation of the entire power supply system.

[0005] In addition, the existing explosion-proof junction boxes also lack the function of real-time working condition information collection and display. This makes it impossible for maintenance personnel to timely understand the operating status of cables and junction boxes, and it is difficult to carry out preventive maintenance and fault troubleshooting. In the complex and changeable environment of underground coal mines, the lack of such information may lead to delays and inadequacies in maintenance work, further increasing the risk of electrical accidents.

[0006] In summary, the existing explosion-proof high and low voltage junction boxes in underground coal mines have certain deficiencies in terms of function and safety. In order to meet the higher requirements of the underground coal mine electrical system for safety and reliability, it is necessary to improve and innovate the existing explosion-proof junction boxes. By adding monitoring functions, realizing real-time working condition information collection and display, etc., the electrical safety level in underground coal mines can be significantly improved, the occurrence of electrical accidents can be reduced, and the safe and smooth progress of coal mine production can be ensured. Summary of the Invention

[0007] The present invention aims to provide an explosion-proof intelligent junction box with monitoring function for coal mines, so as to solve the problems of single function of existing explosion-proof junction boxes and inability to monitor the operation status of cables in real time, and improve the electrical safety in coal mine shafts.

[0008] The present invention realizes the above object through the following technical solutions:

[0009] An explosion-proof intelligent junction box with monitoring function for coal mines, comprising:

[0010] An explosion-proof housing and a cable inlet device. A detachable explosion-proof upper cover is arranged on the upper side of the explosion-proof housing. The explosion-proof upper cover is provided with an observation window, and a control and display unit for displaying the operation information of the cable is installed inside. The cable inlet device is used for sealing and fixing armored cables and rubber-sheathed cables;

[0011] Power-taking terminal posts, arranged inside the explosion-proof housing, obtaining stable power supplies for each phase of A, B, and C by using the voltage division principle, and providing working power supplies for each sensor and the control and display unit;

[0012] Temperature monitoring terminal posts, arranged inside the explosion-proof housing, for monitoring the temperature of the cable joint part;

[0013] Wherein, the control and display unit is an embedded product system composed of a single chip microcomputer, and is at least used to realize functions such as voltage and current indication of high-voltage cables or low-voltage cables, grounding sheath current detection, partial discharge, arc light and temperature rise monitoring, cavity humidity monitoring, infrared remote control operation and data communication upload.

[0014] According to the explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, when the explosion-proof intelligent junction box is a high-voltage junction box, the power-taking terminal posts are high-voltage terminal posts with power-taking function, used to obtain stable power supplies by using the voltage division principle through passive capacitor and resistor devices in a high-voltage environment; meanwhile, the temperature monitoring terminal posts are high-voltage terminal posts with temperature monitoring function, used to monitor the temperature of the cable joint part in a high-voltage environment.

[0015] According to the explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, when the explosion-proof intelligent junction box is a low-voltage junction box, the power-taking terminal posts are low-voltage terminal posts with power-taking function, used to obtain stable power supplies by using the voltage division principle through passive capacitor and resistor devices in a low-voltage environment, and the temperature monitoring terminal posts are low-voltage terminal posts with temperature monitoring function, used to monitor the temperature of the cable joint part in a low-voltage environment.

[0016] An explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, the control and display unit includes a core single-chip microcomputer, a signal processing and receiving unit, a power management unit, a display unit and a communication unit. The signal processing and receiving unit is used to receive signals from a temperature sensor, a humidity sensor, a partial discharge sensor, an arc light sensor and a grounding sheath current sensor, and these signals are respectively used to reflect the temperature of the cable joint part, the humidity inside the explosion-proof cavity, the partial discharge condition of the cable, the arc light generation condition and the magnitude of the grounding sheath current. The display unit is used to display the cable operation information in real time, at least including key parameters such as voltage, current, temperature, humidity, partial discharge state, arc light state and grounding sheath current. The communication unit is used to realize remote communication upload of data and infrared remote control operation, and at least includes at least one communication method such as 4G, 5G, LoRa, WiFi, Bluetooth, etc.

[0017] An explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, the cable inlet device includes a sealing ring type cable inlet device or a casting and curing filler sealing type cable inlet device, and according to the number of cable connections, it is flexibly designed into a two-outlet, three-outlet, four-outlet or more than four-outlet type in terms of the outlet form.

[0018] An explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, the control and display unit is used to realize the following specific functions:

[0019] Voltage and current indication: The voltage and current signals of high-voltage cables or low-voltage cables are respectively collected in real time through a voltage sensor and a current sensor. After being processed by a signal conditioning circuit, they are input into the core single-chip microcomputer for calculation and analysis, and finally the voltage and current values of the cable are intuitively displayed on the display unit in the form of numbers or analog pointers; when an abnormality is detected, the alarm mechanism is triggered and relevant data is uploaded.

[0020] Grounding sheath current detection: The grounding sheath current of the cable is monitored in real time through a grounding sheath current monitoring module. When an abnormal current is detected, the alarm mechanism is immediately triggered, an alarm message is sent through the control and display unit, and relevant data can be uploaded to the remote monitoring center.

[0021] Partial discharge, arc light and temperature rise monitoring: The partial discharge acquisition unit monitors the partial discharge condition of the cable in real time through ultra-high frequency, ultrasonic and earth current sensors; the arc light sensor is used to detect whether arc light is generated at the cable joint or inside the cavity; the temperature sensor monitors the temperature of the cable joint part in real time. The signals collected by these sensors are processed by a signal conditioning circuit and then input into the core single-chip microcomputer for judgment and processing. When an abnormality is detected, the alarm mechanism is triggered and relevant data is uploaded.

[0022] Cavity humidity monitoring: The humidity inside the explosion-proof cavity is monitored in real time through a humidity sensor. When the humidity exceeds the preset threshold, the alarm mechanism is triggered to ensure that the cable and junction box operate in a suitable humidity environment;

[0023] Infrared remote control operation: The control display unit is built with an infrared receiving unit, which can receive operation instructions from an infrared remote control to achieve remote control and setting of the junction box;

[0024] Data communication and upload: The control display unit realizes the data communication and upload function with the remote monitoring center through the built-in communication unit, and uploads the collected cable operation data and alarm information to the monitoring center in real time.

[0025] According to an explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, the partial discharge acquisition unit specifically realizes the acquisition processes of UHF, ultrasonic wave, and earth current wave, including the following steps:

[0026] Initialize acquisition parameters: Set the acquisition frequencies, sampling points, and thresholds of the UHF sensor, ultrasonic sensor, and earth current wave sensor;

[0027] Start acquisition: Send a start signal through the core single-chip microcomputer to synchronously control the UHF sensor, ultrasonic sensor, and earth current wave sensor to start acquiring partial discharge signals;

[0028] Signal processing: Filter, amplify, and perform analog-to-digital conversion on the acquired UHF signals, ultrasonic signals, and earth current wave signals to extract effective partial discharge characteristic information;

[0029] Characteristic extraction: According to the processed signals, extract characteristic parameters such as the amplitude A, phase φ, and frequency f of the partial discharge;

[0030] Judgment and alarm: Compare the extracted characteristic parameters with the preset thresholds. If the amplitude A exceeds Tus or Tge, or the frequency f falls within the preset partial discharge frequency range, it is judged that there is a partial discharge phenomenon, and an alarm message is sent through the control display unit;

[0031] Data storage and upload: Store the acquired partial discharge data and judgment results in the local memory, and upload them to the remote monitoring center through the communication unit.

[0032] According to an explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, when realizing infrared remote control operation, an infrared pyroelectric sensor is used as the human body approach detection module, and its detection range is set as a fan-shaped area with a distance d = 1m to 3m in front of the junction box, and the detection angle θ = 120°;

[0033] When a human body is detected approaching, the core single-chip microcomputer triggers the infrared remote control receiving module to enter the standby state, ready to receive remote control instructions; the infrared receiving unit uses a high-sensitivity infrared receiving head, and its receiving frequency range is from 38 kHz to 40 kHz, which matches the transmitting frequency of the infrared remote control; after the signal output by the receiving head is decoded, the encoded value of the remote control instruction is obtained; the core single-chip microcomputer judges the user's intention according to the encoded value and performs corresponding parameter setting or data reading operations;

[0034] By sending a parameter setting instruction through the infrared remote control, after receiving the instruction, the core single-chip microcomputer calculates the new parameter value according to the preset formula or algorithm and updates the parameter configuration stored in the local memory; the formula for setting the voltage threshold Vth is: Vth = Vbase + ΔV, where Vbase is the basic voltage threshold and ΔV is the increment value set by the user through the remote control; when the user sends a data reading instruction through the infrared remote control, after receiving the instruction, the core single-chip microcomputer reads the corresponding information from the local memory or the real-time collected data and sends the data back to the remote control through the infrared remote control transmitting module; the infrared remote control transmitting module uses the same transmitting frequency and encoding method as the receiving module to ensure accurate data transmission.

[0035] According to an explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, the ground sheath current monitoring module includes a ground loop current acquisition module, a ground loop current sensor and a fault current sensor. The ground loop current sensor uses a Hall effect sensor and is installed on the ground wire of the cable to monitor the ground loop current of the cable in real time; the ground loop current acquisition module processes the digital signal, calculates the real-time value of the ground loop current, and transmits the data to the control and display unit through the communication unit for display and storage, and can also upload it to the remote monitoring center;

[0036] The fault current sensor uses a high-sensitivity current transformer and is installed in the main circuit of the cable to monitor the fault current of the cable in real time. Set the threshold of the fault current in the control and display unit. When the monitored fault current exceeds the threshold, the alarm mechanism is immediately triggered, and the fault data is recorded in the local memory at the same time; among them, the fault current monitoring data can be uploaded to the remote monitoring center in real time through the communication unit to realize remote fault early warning and diagnosis.

[0037] According to an explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention, the outer shape of the junction box structure is a cylindrical structure or a rectangular structure, and a safety interlock device is provided between the explosion-proof upper cover and the explosion-proof housing; when the junction box is energized, the safety interlock device will lock the explosion-proof upper cover to prevent it from being opened; only when the junction box is powered off can the safety interlock device be unlocked.

[0038] It can be seen that an explosion-proof intelligent junction box with monitoring function provided by the present invention has significant beneficial effects compared with the existing explosion-proof junction box, which are specifically reflected in the following aspects:

[0039] 1. Enhance the monitoring function and improve safety:

[0040] For the high-voltage junction box, the present invention realizes the real-time monitoring of multiple parameters such as voltage, current, grounding sheath current, partial discharge, arc light, temperature rise and humidity of the high-voltage cable by installing components such as high-voltage terminal posts with power-taking function and control and display units, which helps to timely detect abnormal conditions in the cable operation and prevent the occurrence of electrical accidents. For the low-voltage junction box, the real-time monitoring of parameters such as voltage, current, grounding sheath current, temperature rise and cavity humidity of the low-voltage cable is also realized by installing components such as low-voltage terminal posts with power-taking function and control and display units, improving the safety and reliability of the low-voltage cable operation.

[0041] 2. Improve operation convenience and reduce maintenance costs:

[0042] The control and display unit not only provides intuitive monitoring data display, but also supports infrared remote control operation. This enables maintenance personnel to set parameters and read data without directly contacting the junction box, greatly improving the operation convenience and safety. The data communication and uploading function enables the monitoring data to be transmitted to the remote monitoring center in real time, facilitating centralized management and analysis, timely discovering potential problems, reducing maintenance costs and improving maintenance efficiency.

[0043] 3. Realize early fault warning and improve the stability of the electrical system:

[0044] The grounding loop current acquisition module and grounding loop current sensor can accurately and real-time monitor the grounding loop current of the cable, which helps to timely discover problems in the grounding system and prevent electrical faults caused by poor grounding. The fault current monitoring function can real-time monitor the fault current of the cable. Once the current exceeds the preset threshold, the alarm mechanism is immediately triggered, which can timely discover and handle potential electrical faults, improving the stability and safety of the electrical system.

[0045] 4. Keep the wiring method unchanged and be easy to promote and apply:

[0046] The present invention is improved and innovated on the premise of keeping the wiring methods of the existing coal mine high-voltage and low-voltage explosion-proof junction boxes unchanged, so that the new product does not require large-scale transformation of the existing electrical system during promotion and application, reducing the promotion difficulty and cost.

[0047] In summary, the explosion-proof intelligent junction box with monitoring function for coal mines provided by the present invention significantly improves the safety and stability of the underground electrical system in coal mines, reduces the maintenance cost, by enhancing the monitoring function, improving the operation convenience, realizing early fault warning and keeping the wiring method unchanged, etc.

[0048] The following further elaborates on the present invention in detail with reference to the drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 FIG. is a schematic structural diagram of an explosion-proof high-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0050] Figure 2 FIG. is a schematic diagram of the two-cable outgoing line mode of the explosion-proof high-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0051] Figure 3 FIG. is a schematic diagram of the three-cable outgoing line mode of the explosion-proof high-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0052] Figure 4 FIG. is a schematic structural diagram of an explosion-proof low-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0053] Figure 5 FIG. is a schematic diagram of the two-cable outgoing line mode of the explosion-proof low-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0054] Figure 6 FIG. is a schematic diagram of the three-cable outgoing line mode of the explosion-proof low-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0055] Figure 7 FIG. is a schematic diagram of the first four-cable outgoing line mode of the explosion-proof low-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0056] Figure 8 FIG. is a schematic diagram of the second four-cable outgoing line mode of the explosion-proof low-voltage intelligent junction box in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0057] Figure 9 FIG. is a schematic diagram of the principle of the control and display unit in an embodiment of the explosion-proof intelligent junction box with monitoring function for coal mines of the present invention.

[0058] Figure 10 This is the circuit schematic diagram of the high-voltage live display unit and voltage acquisition unit in an embodiment of an explosion-proof intelligent junction box with monitoring function for coal mines according to the present invention.

[0059] Figure 11 This is the circuit schematic diagram of the implementation of infrared remote control in an embodiment of an explosion-proof intelligent junction box with monitoring function for coal mines according to the present invention. Specific embodiments

[0060] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0061] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0062] See Figures 1 to 11 , this embodiment provides an explosion-proof intelligent junction box with monitoring function for coal mines, including:

[0063] An explosion-proof housing and a cable inlet device. A detachable explosion-proof upper cover is provided on the upper side of the explosion-proof housing. The explosion-proof upper cover is provided with an observation window, and a control display unit for displaying cable operation information is installed inside. The cable inlet device is used for sealing and fixing armored cables and rubber-sheathed cables.

[0064] Power-taking terminal posts are arranged inside the explosion-proof housing and obtain stable power supplies for each of the A, B, and C phases using the voltage division principle to provide working power supplies for each sensor and the control display unit.

[0065] Temperature monitoring terminal posts are arranged inside the explosion-proof housing and are used for monitoring the temperature of the cable joint part.

[0066] The control display unit is an embedded product system composed of a single chip microcomputer and is at least used to realize functions such as voltage and current indication of high-voltage cables or low-voltage cables, detection of grounding sheath current, partial discharge, arc light and temperature rise monitoring, cavity humidity monitoring, infrared remote control operation and data communication upload.

[0067] When the explosion-proof intelligent junction box is a high-voltage junction box, the power-taking terminal is a high-voltage terminal with power-taking function, which is used to obtain a stable power supply by using the voltage division principle through passive capacitor and resistor devices in a high-voltage environment; at the same time, the temperature monitoring terminal is a high-voltage terminal with temperature monitoring function, which is used to monitor the temperature of the cable joint part in a high-voltage environment.

[0068] When the explosion-proof intelligent junction box is a low-voltage junction box, the power-taking terminal is a low-voltage terminal with power-taking function, which is used to obtain a stable power supply by using the voltage division principle through passive capacitor and resistor devices in a low-voltage environment, and the temperature monitoring terminal is a low-voltage terminal with temperature monitoring function, which is used to monitor the temperature of the cable joint part in a low-voltage environment.

[0069] It can be seen that for the high-voltage junction box, in this embodiment, by installing components such as high-voltage terminals with power-taking functions and control display units, real-time monitoring of multiple parameters such as voltage, current, sheath current, partial discharge, arc light, temperature rise, and humidity of high-voltage cables is realized, which helps to timely detect abnormal situations during cable operation and prevent the occurrence of electrical accidents; for the low-voltage junction box, in this embodiment, by installing components such as low-voltage terminals with power-taking functions and control display units, real-time monitoring of parameters such as voltage, current, sheath current, temperature rise, and cavity humidity of low-voltage cables is realized, improving the safety and reliability of low-voltage cable operation.

[0070] Specifically, as Figures 1 to 3 shown, the structure and appearance of the explosion-proof intelligent high-voltage junction box is cylindrical or rectangular (mainly referring to voltage levels of 10 kV, 6 kV, and 3.3 kV), and the upper cover opening method is adopted. Its main structure is composed of an explosion-proof upper cover 13 with an observation window, an explosion-proof housing 16, a main cavity 12, a high-voltage terminal 14 with power-taking function, a high-voltage terminal with temperature monitoring function, a control display unit, an auxiliary ground wire terminal 11, internal and external grounding devices, a cable inlet device 15, etc. Their functions are described as follows:

[0071] Explosion-proof housing: It is mainly composed of components such as an explosion-proof housing 16, an explosion-proof upper cover 13 with an observation window 17, and a cable inlet device 15. The explosion-proof material is mainly in two ways: cast iron or steel. The high-voltage terminal 14 with power-taking function, the high-voltage terminal with temperature monitoring function, the control display unit, and the auxiliary ground wire terminal 11 are all installed inside the explosion-proof housing 16, playing the role of explosion-proof for electrical products; the explosion-proof upper cover 13 with an observation window is composed of components such as an explosion-proof housing and explosion-proof glass, and the control display unit is installed inside, facilitating personnel to observe and monitor cable operation information and perform daily infrared remote control operations.

[0072] The cable entry device 15 mainly includes forms such as the sealing ring type cable entry device and the casting and curing filler sealing type cable entry device, which can achieve the purpose of sealing and fixing armored cables and rubber sheathed cables, and also play the role of electrical explosion protection. According to the number of cable connections, there are two-outlet ( Figure 2 ) and three-outlet ( Figure 3 ) and other types.

[0073] The high-voltage terminal 14 with power-taking function and the high-voltage terminal with temperature monitoring function obtain a stable power supply of 3-8 watts per phase of A, B, and C (DC5V-DC48V) through passive capacitor and resistor devices using the voltage division principle, mainly providing working power for components such as temperature sensors, humidity sensors, partial discharge sensors, and control and display units.

[0074] The control and display unit is an embedded product system composed of a single-chip microcomputer, mainly including a core single-chip microcomputer, signal processing and receiving units for temperature, humidity, partial discharge, arc light, ground sheath current, etc.; a power management unit (whose power is provided by the terminal); a light-emitting diode, digital tube or liquid crystal display unit, infrared receiving unit, communication units such as 4G, 5G, lora, and Wifi, etc. It can realize functions such as voltage and current indication of high-voltage cables, ground sheath current detection, partial discharge, arc light and temperature rise monitoring, humidity monitoring and other signal monitoring, infrared remote control operation, and data communication upload, as Figure 9 shown.

[0075] As Figures 4 to 8 shown, the structure of the explosion-proof intelligent low-voltage junction box is cylindrical or rectangular (mainly referring to voltage levels of 1140V, 660V, 380V, and 127V), and the upper side opening method is adopted. Its main structure consists of an explosion-proof upper cover 23 with an observation window, an explosion-proof housing 26, a main cavity 22, a low-voltage terminal 24 with power-taking function, a low-voltage terminal with temperature monitoring function, a control and display unit, internal and external grounding devices 21, a cable entry device 25, etc. Their functions are described as follows:

[0076] Explosion-proof housing: It mainly consists of an explosion-proof housing 26, an explosion-proof upper cover 23 with an observation window 27, a cable entry device 25, etc. The explosion-proof material is mainly in two ways: cast iron or steel. The low-voltage terminal 24 with power-taking function, the low-voltage terminal with temperature monitoring function, the control and display unit, and the grounding device 21 are all installed inside the explosion-proof housing 26, playing the role of electrical product explosion protection; the explosion-proof upper cover 23 with an observation window consists of an explosion-proof housing, explosion-proof glass, etc., and the control and display unit is installed inside, facilitating personnel to observe and monitor cable operation information and daily infrared remote control operation.

[0077] The cable entry device 25 mainly includes forms such as the sealing ring type cable entry device and the casting and curing filler sealing type cable entry device, which can achieve the purpose of sealing and fixing armored cables and rubber-sheathed cables, and also play the role of electrical explosion protection. There are two-outlet, three-outlet, four-outlet and other types in terms of the outlet form according to the number of cable connections.

[0078] The low-voltage terminal 24 with power-taking function and the low-voltage terminal with temperature monitoring function obtain a stable power supply of 3-8 watts per phase of A, B, and C (DC5V-DC48V) through passive capacitor and resistor devices using the voltage division principle, mainly providing working power for components such as temperature sensors, humidity sensors, partial discharge sensors, and control display units.

[0079] The control display unit is an embedded product system composed of a single-chip microcomputer, mainly including a core single-chip microcomputer; signal processing and receiving units for temperature, humidity, partial discharge, arc light, sheath current, etc.; a power management unit (whose power is provided by the terminal); communication units such as 4G, 5G, LoRa, Wifi, etc. It can realize functions such as voltage and current indication of low-voltage cables, sheath current detection, temperature rise monitoring, cavity humidity monitoring, infrared remote control operation, and data communication upload, as Figure 9 shown.

[0080] In this embodiment, as Figure 9 shown, the control display unit includes a core single-chip microcomputer 1, a signal processing and receiving unit, a power management unit 2, a high-voltage live display unit 3, a communication unit 4, and a voltage acquisition unit 5. The signal processing and receiving unit is used to receive signals from the temperature sensor 34, humidity sensor 35, partial discharge sensor, arc light sensor 33, and sheath current sensor. These signals are respectively used to reflect the temperature of the cable joint, the humidity inside the explosion-proof cavity, the partial discharge situation of the cable, the occurrence of arc light, and the magnitude of the sheath current. The display unit is used to display the cable operation information in real time, including at least but not limited to key parameters such as voltage, current, temperature, humidity, partial discharge state, arc light state, and sheath current. The communication unit 4 is used to realize remote communication upload of data and infrared remote control operation, including at least one communication method such as 4G, 5G, LoRa, WiFi, Bluetooth, etc., so that operators can monitor and operate the junction box away from the site.

[0081] Among them, the circuit principles of the high-voltage live display unit 3 and the voltage acquisition unit 5 are as Figure 10As shown. The high-voltage live display unit 3 monitors the high-voltage live state of the cable in real time through a high-voltage sensor. After converting the high-voltage signal into a low-voltage signal, it is processed by a signal conditioning circuit and then input into the core single-chip microcomputer for judgment and processing. When it detects that the cable is live, the high-voltage live display unit 3 notifies the operator of the live state of the cable in an intuitive manner (such as indicator lights, digital displays, etc.) through the display unit to ensure operation safety. The voltage acquisition unit collects the voltage signal of the cable in real time through a voltage sensor. After being processed by the signal conditioning circuit, it is input into the core single-chip microcomputer for calculation and analysis. The voltage acquisition unit can accurately display the voltage value of the cable and can set the voltage threshold as needed. When the voltage exceeds or is lower than the threshold, the alarm mechanism is triggered.

[0082] In this embodiment, the cable entry device, as a key component of the explosion-proof housing, includes a sealed-ring type cable entry device or a casting and curing filler sealing type cable entry device. Both of these two forms of cable entry devices can effectively seal and fix armored cables and rubber-sheathed cables, ensuring that the connection between the cable and the junction box is both safe and reliable; at the same time, according to the number of cable connections, the outgoing line form is flexibly designed into two-outgoing, three-outgoing, four-outgoing or more than four-outgoing types to meet the requirements for the number of cable connections in different application scenarios.

[0083] In this embodiment, the control and display unit is used to implement the following specific functions:

[0084] Voltage and current indication: The voltage and current signals of high-voltage cables or low-voltage cables are respectively collected in real time through a voltage sensor 31 and a current sensor 32. After being processed by the signal conditioning circuit 6, they are input into the core single-chip microcomputer 1 for calculation and analysis. Finally, the voltage and current values of the cable are intuitively displayed on the display unit in the form of numbers or analog pointers. When an abnormality is detected, the alarm mechanism is triggered and relevant data is uploaded.

[0085] Grounding sheath current detection: The grounding sheath current of the cable is monitored in real time through the grounding sheath current monitoring module 7. When an abnormal current is detected, the alarm mechanism is immediately triggered, an alarm message is sent through the control and display unit, and relevant data can be uploaded to the remote monitoring center.

[0086] Partial discharge, arc light and temperature rise monitoring: The partial discharge acquisition unit 8 monitors the partial discharge situation of the cable in real time through ultra-high frequency, ultrasonic and earth current sensors; the arc light sensor 33 is used to detect whether arc light is generated at the cable joint or in the cavity; the temperature sensor 34 monitors the temperature of the cable joint part in real time. The signals collected by these sensors are processed by the signal conditioning circuit 6 and then input into the core single-chip microcomputer 1 for judgment and processing. When an abnormality is detected, the alarm mechanism is triggered and relevant data is uploaded.

[0087] Cavity humidity monitoring: The humidity inside the explosion-proof cavity is monitored in real time through the humidity sensor 35. When the humidity exceeds the preset threshold, the alarm mechanism is triggered to ensure that the cable and junction box operate in a suitable humidity environment.

[0088] Infrared remote control operation: The control display unit is built with an infrared receiving unit 9, which can receive operation instructions from the infrared remote control to achieve remote control and setting of the junction box.

[0089] Data communication and upload: The control display unit realizes the data communication and upload function with the remote monitoring center through the built-in communication unit 4, and uploads the collected cable operation data and alarm information to the monitoring center in real time.

[0090] In this embodiment, the temperature sensor 34 is a wireless temperature sensor. Due to different power supply and temperature acquisition methods, there are four types of applications:

[0091] A: The electromagnetic field is taken as the sensor power supply by current, and the temperature and humidity data are uploaded once every 8 seconds; the characteristic is that the power supply is related to the current.

[0092] B: The step voltage is used as the power supply of the temperature sensor, and its power supply is related to the voltage and is very stable.

[0093] C: The battery is used as the power supply for temperature and humidity measurement and sends data once every 8 minutes, or directly uploads when the collected data exceeds the dead zone.

[0094] D: RFID temperature measurement, and this type of temperature measurement must provide a high-power emission band power supply.

[0095] E: Fluorescent temperature measurement, which is used for temperature measurement that is wired but completely optically isolated.

[0096] Through the above specific implementation solutions and classification applications, the wireless temperature acquisition module and wireless temperature sensor described in the present invention can flexibly adapt to the temperature monitoring requirements in different environments, and improve the operation safety and reliability of cables and equipment in coal mines.

[0097] In this embodiment, the partial discharge acquisition unit 8 specifically realizes the acquisition processes of ultra-high frequency, ultrasonic wave, and earth current, including the following steps:

[0098] Initializing acquisition parameters: Set the acquisition frequencies, sampling points, and thresholds of the ultra-high frequency sensor, ultrasonic sensor, and earth current sensor; among them, set the acquisition frequency of the ultrasonic sensor as fus = 100 kHz, the sampling points as Nus = 1024 points, and the threshold as Tus = 50 mV (adjustable according to the actual application scenario); set the acquisition frequency of the earth current sensor as fge = 50 kHz, the sampling points as Nge = 512 points, and the threshold as Tge = 30 mV (adjustable according to the actual application scenario).

[0099] Start acquisition: Send a start signal through the core microcontroller 1 to synchronously control the UHF sensor, ultrasonic sensor, and earth current sensor to start collecting partial discharge signals.

[0100] Signal processing: Filter, amplify, and perform analog-to-digital conversion on the collected UHF signals, ultrasonic signals, and earth current signals to extract effective partial discharge characteristic information. Specifically, perform band-pass filtering on the collected ultrasonic signals, with the filtering range set to 20 kHz to 150 kHz to remove low-frequency noise and high-frequency interference; perform low-pass filtering on the earth current signals, with the filtering cut-off frequency set to 10 kHz to retain the main characteristics of the earth current; perform amplification processing on the filtered signals, and the amplification factor is determined according to the amplitude of the sensor output signal and subsequent processing requirements; perform analog-to-digital conversion (ADC) on the amplified signals, with the conversion accuracy not less than 12 bits to meet the requirements of subsequent feature extraction and judgment.

[0101] Feature extraction: According to the processed signals, extract characteristic parameters such as the amplitude A, phase φ, and frequency f of the partial discharge. Among them, the amplitude A can be obtained by calculating the maximum value or root mean square value of the signal; the phase φ can obtain the phase spectrum of the signal through Hilbert transform or Fourier transform, and then extract the phase information; the frequency f can obtain the frequency spectrum of the signal through fast Fourier transform (FFT), and then determine the main frequency components of the partial discharge signal.

[0102] Judgment and alarm: Compare the extracted characteristic parameters with the preset thresholds. If the amplitude A exceeds Tus or Tge, or the frequency f falls within the preset partial discharge frequency range, it is judged that there is a partial discharge phenomenon, and an alarm message is sent through the control display unit; an alarm message is sent through the display unit, including key information such as the time, location, amplitude, and frequency of the partial discharge occurrence.

[0103] Data storage and upload: Store the collected partial discharge data and judgment results in the local memory, and upload them to the remote monitoring center through the communication unit 4. The upload frequency can be set according to actual needs, such as uploading once per hour or in real time.

[0104] In this embodiment, when implementing infrared remote control operation, an infrared pyroelectric sensor is used as the human body approach detection module, and its detection range is set to a fan-shaped area with a distance d = 1 m to 3 m in front of the junction box, and the detection angle θ = 120°, specifically as Figure 11 shown.

[0105] When a human body is detected approaching, the core single-chip microcomputer 1 triggers the infrared remote control receiving module to enter the standby state, ready to receive remote control instructions; the infrared receiving unit 9 uses a high-sensitivity infrared receiving head, whose receiving frequency range is from 38 kHz to 40 kHz, matching the transmitting frequency of the infrared remote control; after the signal output by the receiving head is decoded, the encoded value of the remote control instruction is obtained; the core single-chip microcomputer 1 judges the user's intention according to the encoded value and executes the corresponding parameter setting or data reading operation.

[0106] By sending parameter setting instructions through the infrared remote control, after receiving the instructions, the core single-chip microcomputer 1 calculates the new parameter values according to the preset formulas or algorithms and updates the parameter configuration stored in the local memory; the formula for setting the voltage threshold Vth is: Vth = Vbase + ΔV, where Vbase is the basic voltage threshold and ΔV is the increment value set by the user through the remote control; when the user sends a data reading instruction through the infrared remote control, after receiving the instruction, the core single-chip microcomputer 1 reads the corresponding information from the local memory or the real-time collected data and sends the data back to the remote control through the infrared remote control transmitting module; the infrared remote control transmitting module uses the transmitting frequency and encoding method matching the receiving module to ensure accurate data transmission.

[0107] The control display unit not only provides intuitive monitoring data display but also supports infrared remote control operation. This enables maintenance personnel to set parameters and read data without directly touching the junction box, greatly improving the convenience and safety of operation. The data communication and uploading function enables the monitoring data to be transmitted to the remote monitoring center in real time, facilitating centralized management and analysis, timely detecting potential problems, reducing maintenance costs, and improving maintenance efficiency.

[0108] In this embodiment, the ground sheath current monitoring module 7 includes a ground loop current acquisition module, a ground loop current sensor, and a fault current sensor. The ground loop current sensor uses a Hall effect sensor and is installed on the ground wire of the cable to monitor the ground loop current of the cable in real time; the ground loop current acquisition module processes the digital signal, calculates the real-time value of the ground loop current, and transmits the data to the control display unit through the communication unit 4 for display and storage, and can also upload it to the remote monitoring center.

[0109] The fault current sensor uses a high-sensitivity current transformer and is installed in the main circuit of the cable to monitor the fault current of the cable in real time. Set the threshold of the fault current in the control display unit. When the monitored fault current exceeds the threshold, immediately trigger the alarm mechanism and record the fault data in the local memory at the same time; among them, the fault current monitoring data can be uploaded to the remote monitoring center in real time through the communication unit 4 to achieve remote fault warning and diagnosis.

[0110] The ground loop current acquisition module and the ground loop current sensor can accurately and real-time monitor the ground loop current of the cable, which helps to detect problems in the grounding system in a timely manner and prevent electrical faults caused by poor grounding. The fault current monitoring function can real-time monitor the fault current of the cable. Once the current exceeds the preset threshold, the alarm mechanism will be triggered immediately, which can detect and handle potential electrical faults in a timely manner and improve the stability and safety of the electrical system.

[0111] In this embodiment, the outer shape of the junction box structure is a cylindrical structure or a rectangular structure, and the outer shell is made of high-strength and corrosion-resistant metal materials (such as cast iron or steel) or high-strength engineering plastics to ensure sufficient mechanical strength and protection ability in the harsh underground coal mine environment. The cylindrical design helps to evenly disperse the external pressure and improve the compressive performance of the junction box; the rectangular design is convenient for the layout and installation of internal components, and is also beneficial to the connection and fixation with external devices.

[0112] A safety interlock device is provided between the explosion-proof upper cover and the explosion-proof housing; when the junction box is energized, the safety interlock device will lock the explosion-proof upper cover to prevent it from being opened; only when the junction box is de-energized can the safety interlock device be unlocked.

[0113] The present invention makes improvements and innovations without changing the existing wiring methods of high-voltage and low-voltage explosion-proof junction boxes in coal mines, so that when the new product is popularized and applied, there is no need to carry out large-scale transformation of the existing electrical system, reducing the popularization difficulty and cost.

[0114] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as these combinations of technical features do not conflict, they should be considered to be within the scope described in this specification.

[0115] The above embodiments are only the preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the scope required to be protected by the present invention.

Claims

1. An explosion-proof intelligent junction box with monitoring function for coal mines, characterized in that, Including: An explosion-proof housing and a cable entry device. A detachable explosion-proof upper cover is provided on the upper side of the explosion-proof housing. The explosion-proof upper cover is provided with an observation window, and a control and display unit for displaying cable operation information is installed inside. The cable entry device is used for sealing and fixing armored cables and rubber-sheathed cables; Power-taking terminal posts, which are arranged inside the explosion-proof housing and obtain a stable power supply for each phase of A, B, and C by using the voltage division principle to provide a working power supply for each sensor and the control and display unit; Temperature monitoring terminal posts, which are arranged inside the explosion-proof housing and are used for monitoring the temperature of the cable joint part; Among them, the control and display unit is an embedded product system composed of a single chip microcomputer, and is at least used to realize functions such as voltage and current indication of high-voltage cables or low-voltage cables, grounding sheath current detection, partial discharge, arc light and temperature rise monitoring, cavity humidity monitoring, infrared remote control operation, and data communication upload.

2. The explosion-proof intelligent junction box according to claim 1, wherein: When the explosion-proof intelligent junction box is a high-voltage junction box, the power-taking terminal post is a high-voltage terminal post with a power-taking function, which is used to obtain a stable power supply by using the voltage division principle through passive capacitor and resistor devices based on the characteristic of stable high-voltage. At the same time, the temperature monitoring terminal post is a high-voltage terminal post with a contact temperature monitoring function, which is used to monitor the temperature of the cable joint part in a high-voltage environment.

3. The explosion-proof intelligent junction box according to claim 1, wherein: When the explosion-proof intelligent junction box is a low-voltage junction box, the power-taking terminal post is a low-voltage terminal post with a power-taking function, which is used to obtain a stable power supply by using the voltage division principle through passive capacitors, resistors, and LC devices based on the characteristic of stable voltage in a low-voltage environment. The temperature monitoring terminal post is a low-voltage terminal post with a temperature monitoring function, which is used to monitor the temperature of the cable joint part in a low-voltage environment.

4. The explosion-proof intelligent junction box according to claim 1, wherein: The control and display unit includes a core single chip microcomputer, a signal processing and receiving unit, a power management unit, a display unit, and a communication unit. The signal processing and receiving unit is used to receive signals from temperature sensors, humidity sensors, partial discharge sensors, arc light sensors, and grounding sheath current sensors. These signals are respectively used to reflect the temperature of the cable joint part, the humidity inside the explosion-proof cavity, the partial discharge condition of the cable, the arc light generation condition, and the magnitude of the grounding sheath current. The display unit is used to display cable operation information in real time, at least including key parameters such as voltage, current, temperature, humidity, partial discharge state, arc light state, and grounding sheath current. The communication unit is used to realize remote communication upload and infrared remote control operation of data, and at least includes at least one communication method such as 4G, 5G, LoRa, WiFi, and Bluetooth.

5. The explosion-proof intelligent junction box according to claim 1, wherein: The cable entry device includes a sealing ring type cable entry device or a casting and curing filler sealing type cable entry device, and is flexibly designed into a two-outlet, three-outlet, four-outlet or more than four-outlet type according to the number of cable connections.

6. The explosion-proof intelligent junction box according to claim 4, wherein: The control and display unit is used to implement the following specific functions: Voltage and current indication: The voltage and current signals of the high-voltage cable or low-voltage cable are respectively collected in real time through a voltage sensor and a current sensor. After being processed by the signal conditioning circuit, they are input into the core single-chip microcomputer for calculation and analysis, and finally the voltage and current values of the cable are visually displayed on the display unit in the form of numbers or analog pointers; when an abnormality is detected, the alarm mechanism is triggered and relevant data is uploaded. Grounding sheath current detection: The grounding sheath current of the cable is monitored in real time through the grounding sheath current monitoring module. When an abnormal current is detected, the alarm mechanism is immediately triggered, and an alarm message is sent through the control and display unit, and relevant data can be uploaded to the remote monitoring center. Partial discharge, arc light and temperature rise monitoring: The partial discharge acquisition unit monitors the partial discharge situation of the cable in real time through ultra-high frequency sensors, ultrasonic and earth current sensors; the arc light sensor is used to detect whether there is arc light in the cable joint or cavity; the flame sensor; the temperature sensor detects the temperature of the cable joint part in real time. The signals collected by these sensors are processed by the signal conditioning circuit and then input into the core single-chip microcomputer for judgment and processing. When an abnormality is detected, the alarm mechanism is triggered and relevant data is uploaded. Cavity humidity and water immersion monitoring: The humidity situation inside the explosion-proof cavity is monitored in real time through a humidity sensor. When the humidity and water immersion exceed the preset threshold, the alarm mechanism is triggered to ensure that the cable and the junction box operate in a suitable humidity environment. Infrared remote control operation: The control and display unit is built-in with an infrared receiving unit, which can receive operation instructions from an infrared remote control to realize the setting of internal parameters of the junction box, and can also wake up the human-machine liquid crystal interface. Data communication and upload: The control and display unit realizes the data communication and upload function with the remote monitoring center through the built-in communication unit, and uploads the collected cable operation data and alarm information to the monitoring center in real time.

7. The explosion-proof intelligent junction box according to claim 6, wherein: The partial discharge acquisition unit specifically implements the acquisition processes of ultra-high frequency, ultrasonic and earth current, including the following steps: Initialize the acquisition parameters: Set the acquisition frequencies, sampling points and thresholds of the ultra-high frequency sensor, ultrasonic sensor and earth current sensor. Start acquisition: Send a start signal through the core single-chip microcomputer to synchronously control the ultra-high frequency sensor, ultrasonic sensor and earth current sensor to start collecting partial discharge signals. Signal processing: Filter, amplify and perform analog-to-digital conversion on the collected ultra-high frequency signals, ultrasonic signals and earth current signals to extract effective partial discharge characteristic information. Feature extraction: According to the processed signals, extract the amplitude PC parameters of the partial discharge; qualitatively determine the degree of partial discharge Judgment and alarm: Compare the extracted characteristic parameters with the preset threshold. If the amplitude PC exceeds Tus or Tge, or the frequency f falls within the preset partial discharge frequency range, it is determined that there is a partial discharge phenomenon, and an alarm message is sent through the control and display unit. Data storage and upload: The collected partial discharge data and judgment results are stored in the local memory and uploaded to the remote monitoring center through the communication unit.

8. The explosion-proof intelligent junction box according to claim 6, characterized in that: When realizing infrared remote control operation, an infrared pyroelectric sensor is used as the human body proximity detection module, and its detection range is set as a fan-shaped area with a distance d = 1m to 3m in front of the junction box, and the detection angle θ = 120°; When a human body is detected to be approaching, the core single-chip microcomputer triggers the infrared remote control receiving module to enter the standby state to prepare for receiving remote control instructions; the infrared receiving unit uses a high-sensitivity infrared receiving head, and its receiving frequency range is 38kHz to 40kHz, which matches the transmission frequency of the infrared remote control; after the signal output by the receiving head is decoded, the encoded value of the remote control instruction is obtained; The core single-chip microcomputer judges the user's intention according to the encoded value and executes the corresponding parameter setting or data reading operation; at the same time, the human-machine interface is lit. By sending a parameter setting instruction through the infrared remote control, after the core single-chip microcomputer receives the instruction, it calculates a new parameter value according to a preset formula or algorithm and updates the parameter configuration stored in the local memory; The formula for setting the voltage threshold Vth is: Vth = Vbase + ΔV, where Vbase is the basic voltage threshold and ΔV is the increment value set by the user through the remote control; the user sends a data reading instruction through the infrared remote control, and after the core single-chip microcomputer receives the instruction, it reads the corresponding information from the local memory or the real-time collected data and sends the data back to the remote control through the infrared remote control transmitting module; The infrared remote control transmitting module uses a transmitting frequency and coding method that matches the receiving module to ensure accurate data transmission.

9. The explosion-proof intelligent junction box according to claim 6, characterized in that: The grounding sheath current monitoring module includes a grounding loop current acquisition module, a grounding loop current sensor and a fault current sensor. The grounding loop current sensor uses a Hall effect sensor and is installed on the grounding wire of the cable to monitor the grounding loop current of the cable in real time; The grounding loop current acquisition module processes the digital signal, calculates the real-time value of the grounding loop current, and transmits the data to the control display unit through the communication unit for display and storage, and can also be uploaded to the remote monitoring center; The fault current sensor uses a high-sensitivity current transformer and is installed in the main circuit of the cable to monitor the fault current of the cable in real time. The threshold of the fault current is set in the control display unit. When the monitored fault current exceeds the threshold, the alarm mechanism is immediately triggered, and at the same time, the fault data is recorded in the local memory; among them, the fault current monitoring data can be uploaded to the remote monitoring center in real time through the communication unit to realize remote fault early warning and diagnosis.

10. The explosion-proof intelligent junction box according to any one of claims 1 to 9, characterized in that: The outer shape of the junction box structure is a cylindrical structure or a rectangular structure, and a safety interlock device is provided between the explosion-proof upper cover and the explosion-proof housing; when the junction box is energized, the safety interlock device will lock the explosion-proof upper cover to prevent it from being opened; only when the junction box is powered off can the safety interlock device be unlocked.

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