Low voltage cable branch box and system

Abstract

This invention discloses a low-voltage cable branch box and system, belonging to the field of cable installation technology. The low-voltage cable branch box includes a box body, the inner cavity of which is provided with a busbar and wiring terminals disposed on the front side of the busbar; it also includes a heat dissipation device, which includes a phase change heat-conducting plate and a finned heat sink. The phase change heat-conducting plate is disposed on the back side of the busbar, and the finned heat sink is disposed on the outer wall of the box body. The phase change heat-conducting plate penetrates the box wall and connects to the finned heat sink. This invention can improve heat dissipation efficiency and reduce the risk of electric shock without compromising sealing.

Description

Technical Field

[0001] This invention relates to the field of cable installation technology, and in particular to a low-voltage cable branch box and system. Background Technology

[0002] Low-voltage cable distribution boxes are indispensable connection devices in power distribution networks, widely used in urban power distribution networks, residential areas, industrial parks, commercial complexes, and other locations for cable branching, switching, protection, and metering. Existing distribution boxes mostly rely on natural convection cooling on the box surface, making it difficult to quickly dissipate heat generated by the internal busbars and terminals. Especially under high load or high-temperature conditions, the internal temperature continues to rise, leading to the following consequences: accelerated aging of insulation materials: The cable insulation layer, busbar insulation sleeve, and internal conductors are exposed to high temperatures for extended periods, causing accelerated degradation of their mechanical strength and electrical performance, shortening their service life; increased contact resistance: The connection between the terminals and the busbars loosens due to thermal expansion and contraction, increasing contact resistance with rising temperature, creating a vicious cycle of "heating → increased resistance → even hotter"; increased failure rate: High-temperature environments accelerate the aging of sealing materials, leading to a decrease in protection levels and further causing faults such as moisture absorption and short circuits. Some products attempt to add ventilation holes to the box to enhance convection cooling, but this reduces sealing performance, creating a technical contradiction of "dissipation and sealing being mutually exclusive."

[0003] In addition, during the operation and maintenance of low-voltage cable branch boxes, most of the internal busbars and terminals of the branch boxes are not equipped with effective physical isolation protection, so maintenance personnel are at risk of accidentally touching live parts during inspection or maintenance; and there is a lack of real-time monitoring. Existing products do not have functions such as terminal temperature monitoring and leakage detection, so they cannot provide early warning before a fault occurs, and maintenance personnel lack an intuitive understanding of the equipment status.

[0004] Therefore, there is an urgent need for a new type of material transport device, a low-voltage cable branch box and system, to solve the above-mentioned problems existing in the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a low-voltage cable branch box and system that can improve heat dissipation efficiency and reduce the risk of electric shock without compromising the sealing performance.

[0006] To achieve the above objectives, the present invention provides a low-voltage cable branch box, including a box body, an inner cavity of which is provided with a busbar and wiring terminals provided on the front side of the busbar, and a heat dissipation device, which includes a phase change heat conduction plate and a finned heat sink. The phase change heat conduction plate is provided on the back side of the busbar, and the finned heat sink is provided on the outer wall of the box body. The phase change heat conduction plate penetrates the box wall and is connected to the finned heat sink.

[0007] Preferably, the heat dissipation device further includes a phase change thermally conductive pad, which is disposed between the terminal block and the busbar.

[0008] Preferably, the inner cavity of the enclosure is provided with a cable bracket, the cable bracket including a crossbeam and a vertical beam, the vertical beam being arranged on the inner side wall of the enclosure along the vertical direction of the enclosure, the vertical beam being provided with a plurality of first mounting holes, the two ends of the crossbeam being respectively arranged on the first mounting holes on the two oppositely arranged vertical beams, the crossbeam being provided with a plurality of second mounting holes, and the phase change heat conduction plate being arranged on the crossbeam.

[0009] Preferably, a visible insulating cover is detachably installed on the busbar, and the visible insulating cover covers the connection between the terminal block and the busbar.

[0010] Preferably, the busbar is provided with a first mounting groove, which is adapted to the plug-in portion of the visible insulating cover.

[0011] Preferably, the visible insulating cover has a heat dissipation channel.

[0012] Preferably, a live detection device is provided inside the visible insulating cover. The live detection device is used to detect whether there is leakage at the connection between the terminal block and the busbar. The live detection device is arranged opposite to the terminal block.

[0013] Preferably, the live detection device includes a test pen, a second mounting slot, a spring, and a resistor. The second mounting slot is disposed on the inner wall of the visible insulating cover. One end of the spring is connected to the test pen, and the other end is connected to the second mounting slot. The test end of the test pen abuts against the terminal block, and the non-test end of the test pen is connected to the resistor, which is grounded.

[0014] Preferably, a temperature detection device is provided on the inner wall of the visible insulating cover.

[0015] This invention provides a low-voltage cable branch box system, including a control module and the low-voltage cable branch box. The control module includes a data receiving unit, a data analysis unit, and an alarm output unit. The data receiving unit is used to receive real-time data sent by a live detection device and a temperature detection device. The data analysis unit is used to determine whether the real-time data exceeds a preset threshold or whether liveness is detected. The alarm output unit is used to send alarm information to the maintenance terminal when the preset threshold is exceeded.

[0016] The advantages and positive effects of the low-voltage cable branch box and system described in this invention are: 1. By installing a phase change heat conduction plate on the back of the busbar, the characteristic of phase change materials absorbing a large amount of latent heat during the solid-liquid phase change process can be utilized to quickly dissipate the Joule heat generated by the busbar under load current, suppressing the sudden temperature rise at the busbar and terminal connection points. The phase change heat conduction plate penetrates the enclosure wall and connects directly to the outer finned heat sink, forming a low thermal resistance metal heat conduction path without compromising the seal. The heat from the busbar is directly transferred to the outer fins through the phase change heat conduction plate and carried away by the ambient air, preventing heat from remaining inside the enclosure and improving heat dissipation.

[0017] 2. By setting up a detachable and visible insulating cover, physical isolation and protection of live connections are achieved, while allowing maintenance personnel to directly observe the internal condition without removing the cover, thus improving the safety and convenience of inspections.

[0018] 3. The live detection device and temperature detection device are integrated inside the visible insulating cover, which can monitor the live status and temperature changes of the wiring terminals in real time, promptly detect potential problems such as poor contact and overload heating, and prevent the fault from escalating.

[0019] 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

[0020] Figure 1 This is a schematic diagram of the structure of one embodiment of the present invention; Figure 2 Embodiments of the present invention Figure 1 Enlarged view of point A; Figure 3 This is a front view structural diagram of the box body according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the busbar and the visible insulating cover according to an embodiment of the present invention; Figure 5 Embodiments of the present invention Figure 4 Enlarged view of point B; Figure 6 This is a schematic diagram of the structure of a visible insulating cover according to an embodiment of the present invention; Figure 7 This is a cross-sectional view of the visible insulating cover of the busbar according to an embodiment of the present invention; Figure Labels 1. Enclosure; 2. Enclosure door; 3. Cable; 4. Cable inlet; 5. Busbar; 6. Terminal block; 7. Phase change heat conduction plate; 8. Finned radiator; 9. Phase change heat conduction pad; 10. Bolt; 11. Crossbeam; 12. Second mounting hole; 13. Vertical beam; 14. First mounting hole; 15. Visible insulating cover; 16. Second mounting slot; 17. Heat dissipation channel; 18. Test pen; 19. First mounting slot; 20. Spring; 21. Temperature detection device; 22. Cable tie. Detailed Implementation

[0021] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] Reference Figure 1-7 A low-voltage cable branch box includes a box body 1. The inner cavity of the box body 1 is provided with a busbar 5 and a wiring terminal 6 provided on the front of the busbar 5. It also includes a heat dissipation device, which includes a phase change heat conduction plate 7 and a finned heat sink 8. The phase change heat conduction plate 7 is provided on the back of the busbar 5, and the finned heat sink 8 is provided on the outer wall of the box body 1. The phase change heat conduction plate 7 penetrates the box wall of the box body 1 and is connected to the finned heat sink 8.

[0025] Understandably, the outer surface of the phase change heat conduction plate 7 is fixedly connected to the base plate of the finned heat sink 8 by bolts 10. The heat generated by the busbar 5 and the terminal block 6 is first conducted to the phase change heat conduction plate 7, which then transfers the heat to the finned heat sink 8 outside the enclosure 1. Finally, the finned heat sink 8 dissipates the heat into the surrounding air. This heat dissipation process does not require ventilation holes, achieving a balance between efficient heat dissipation and enclosure 1 sealing. At the same time, since there is no need to open ventilation holes on the enclosure 1, the protection level of the enclosure 1 is maintained, preventing water, dust, and moisture from entering the interior of the enclosure 1.

[0026] It should be noted that the enclosure 1 and the door 2 can be made of high-strength insulating composite material through integral injection molding. The cable inlet 4 is used for the cable 3 to enter. The phase change heat conduction plate 7 is filled with solid-liquid phase change material (such as paraffin / expanded graphite composite phase change material). The inner side of the phase change heat conduction plate 7 is tightly attached to the back of the busbar 5, and thermal grease can be applied between them to reduce contact thermal resistance. The phase change heat conduction plate 7 passes through the through hole opened on the side wall of the enclosure 1, and a sealing ring is set at the through hole to ensure the airtightness of the enclosure 1. The leakage protection device, overload and short circuit protection device, conventional grounding protection system (grounding busbar, grounding terminal, grounding conductor), surge protector (SPD), and insulating support components conventionally installed in low-voltage cable branch boxes are common knowledge in this field, and the specific structure and working principle of the above conventional components will not be described in detail.

[0027] The phase change heat conduction plate 7 utilizes the latent heat of the solid-liquid phase change of the phase change material to maintain a constant temperature while absorbing a large amount of heat, thus possessing heat storage and buffering capabilities. When the load experiences instantaneous thermal shock due to sudden high current, short-circuit faults, or other reasons, the phase change material in the phase change heat conduction plate 7 can absorb a large amount of latent heat during the melting process, maintaining a relatively constant nearby temperature, suppressing instantaneous thermal shock, and reducing the probability of a temperature spike in the terminal 6. The phase change heat conduction plate 7 exhibits uniform heat conduction and excellent heat dissipation performance.

[0028] In one specific embodiment, the heat dissipation device is further optimized by providing a phase change heat conduction plate 7 on the outer wall of the housing 1. The phase change heat conduction plate 7 on the outer wall of the housing 1 is connected to the phase change heat conduction plate 7 disposed in the inner cavity of the housing 1. The phase change heat conduction plate 7 on the outer wall of the housing 1 makes surface-to-surface contact with the substrate of the finned heat sink 8, increasing the contact area and improving the heat dissipation rate. The heat generated by the busbar 5 and the terminal block 6 is first conducted to the phase change heat conduction plate 7 disposed in the inner cavity of the housing 1. The phase change heat conduction plate 7 transfers the heat to the phase change heat conduction plate 7 on the outer wall of the housing 1, and then the phase change heat conduction plate 7 on the outer wall of the housing 1 transfers the heat to the finned heat sink 8 outside the housing 1. Finally, the finned heat sink 8 dissipates the heat into the surrounding air. This heat dissipation process eliminates the need for ventilation holes, achieving a balance between efficient heat dissipation and a sealed enclosure 1. Simultaneously, since no ventilation holes are required on the enclosure 1, its protection level is maintained, preventing water, dust, and moisture from entering the enclosure 1. In one specific embodiment, the heat dissipation device is further optimized by including a phase change thermally conductive pad 9, which is positioned between the terminal block 6 and the busbar 5.

[0029] It is understandable that the phase change thermal pad 9 is filled with a solid-liquid phase change material (such as paraffin / expanded graphite composite phase change material). The phase change thermal pad 9 is located at the connection interface between the terminal 6 and the busbar 5. The terminal 6 is fixedly installed on the front side of the busbar 5 by bolts 10.

[0030] During installation, the phase change thermal pad 9 is pre-placed between the contact surfaces of the terminal 6 and the busbar 5. When the bolt 10 is tightened, the phase change thermal pad 9 is compressed, filling the microscopic gap between the two metal contact surfaces. With the addition of the phase change thermal pad 9, the heat from the terminal 6 can be transferred to the phase change thermal plate 7 inside the housing 1 through air conduction, and also through the busbar 5. Then, it can be dissipated through the finned heat sink 8, effectively preventing the terminal 6 from aging prematurely or increasing its contact resistance due to overheating.

[0031] In one specific embodiment, the inner cavity of the housing 1 is provided with a cable bracket, which includes a crossbeam 11 and a vertical beam 13. The vertical beam 13 is arranged on the inner side wall of the housing 1 along the vertical direction of the housing 1. The vertical beam 13 is provided with a plurality of first mounting holes 14. The two ends of the crossbeam 11 are respectively provided on the first mounting holes 14 on the two oppositely arranged vertical beams 13. The crossbeam 11 is provided with a plurality of second mounting holes 12. The crossbeam 11 is provided with a phase change heat conduction plate 7.

[0032] Understandably, by setting an adjustable cable bracket, on the one hand, it is convenient to adjust the installation height of the busbar 5 according to the entry and exit positions of the cable 3, making the cable 3 route more reasonable; on the other hand, the second mounting hole 12 on the crossbeam 11 can be adapted to the positioning and fixing position of the busbar 5. The cable bracket can realize the reliable fixing between the busbar 5 and the housing 1, and at the same time provide a stable installation foundation for the phase change heat conduction plate 7.

[0033] It should be noted that the cable 3 is usually secured with an independent cable clamp or a direct suspended terminal block 6. The former increases the number of parts and cost, while the latter cannot effectively release cable tension. In this embodiment, the existing second mounting hole 12 on the crossbeam 11 is used as the fixing point for the cable tie 22, achieving reliable fixing of the cable 3 without adding extra parts, thus realizing multiple uses for one hole.

[0034] To improve the electric shock safety performance of the branch box, in one specific embodiment, a visible insulating cover 15 is detachably installed on the busbar 5, and the visible insulating cover 15 covers the connection between the terminal block 6 and the busbar 5.

[0035] Understandably, the visible insulating cover 15 can be detachably installed on the busbar 5 via snap-fit, plug-in, or magnetic attachment. After installation, the visible insulating cover 15 surrounds the terminals 6, bolts 10, and the connection area of ​​the busbar 5. Because the cover is transparent, maintenance personnel can observe the internal connection status without disassembly. The visible insulating cover 15 provides physical isolation protection, preventing maintenance personnel from accidentally touching live parts during inspection or maintenance. The transparent material of the visible insulating cover 15 makes observing the internal connection status convenient, eliminating the need for frequent disassembly and reassembly. Furthermore, the detachable design allows for quick removal of the cover for operation when maintenance is required.

[0036] In one specific embodiment, a first mounting groove 19 is provided on the busbar 5, and the first mounting groove 19 is adapted to the insertion part of the visible insulating cover 15.

[0037] Understandably, during installation, the visible insulating cover 15 is aligned with the first mounting groove 19 and pushed in to complete the fixing. By opening a mounting groove on the busbar 5 and inserting it into the insulating cover, reliable fixing can be achieved without additional fasteners, resulting in a simple structure and convenient assembly and disassembly.

[0038] In one specific embodiment, a heat dissipation channel 17 is provided on the visible insulating cover 15.

[0039] Understandably, in order to prevent the terminal block 6 from overheating due to the complete enclosure of the visible insulating cover 15, a heat dissipation channel 17 is provided. The heat dissipation channel 17 provides an effective heat dissipation path for the terminal block 6 while maintaining physical isolation and protection, thus avoiding local overheating caused by the installation of the insulating cover.

[0040] To further enhance the safety performance of the branch box, in one specific embodiment, a live detection device is provided inside the visible insulating cover 15, and the live detection device is arranged opposite to the wiring terminal 6.

[0041] Understandably, when terminal 6 is energized, the energization detection device sends a warning to maintenance personnel via a light signal. By integrating the energization detection device into the visible insulating cover 15, maintenance personnel can determine whether terminal 6 is energized without opening the insulating cover, significantly improving operational safety.

[0042] In one specific embodiment, a live-line detection device is provided, comprising a test pen 18, a second mounting slot 16, a spring 20, and a high-resistance resistor (for simulating the human body). The second mounting slot 16 is disposed on the inner wall of a visible insulating cover 15. One end of the spring 20 is connected to the test pen 18, and the other end is connected to the second mounting slot 16. The testing end of the test pen 18 abuts against the terminal block 6. The non-testing end of the test pen 18 is connected to the resistor, which is grounded by connecting to the grounding busbar of the housing 1. The tail end of the test pen 18 is connected to the grounding busbar of the housing 1 through a high-resistance resistor (e.g., 2MΩ). Thus, when the terminal block 6 is energized, a microampere-level current path is formed, illuminating the neon tube of the test pen 18.

[0043] It is understood that the second mounting slot 16 is a blind or through slot structure, located on the inner wall of the visible insulating cover 15 directly opposite the terminal 6. The spring 20 is installed inside the second mounting slot 16 and is in a compressed state. The test pen 18 is inserted into the second mounting slot 16, with its tail abutting against the spring 20. Its measuring end extends out of the slot under the force of the spring 20 and presses firmly against the surface of the terminal 6. The indicator end of the test pen 18, such as a neon tube, can be observed through the visible insulating cover 15. When the visible insulating cover 15 is fastened to the busbar 5, the spring 20 is compressed, generating an outward elastic force that firmly presses the measuring end of the test pen 18 against the metal surface of the terminal 6. When the terminal 6 is energized, the current is detected by the test pen 18, and the neon tube illuminates to indicate that it is energized. Using the test pen 18 as a live detection device is low-cost, technologically mature, and highly reliable. The design of the spring 20 ensures reliable contact between the measuring end and the terminal 6, maintaining a good electrical connection even in the presence of vibration or thermal expansion and contraction.

[0044] In one specific embodiment, a temperature detection device 21 is provided on the inner wall of the visible insulating cover 15.

[0045] Understandably, the temperature detection device 21 is installed on the inner wall of the visible insulating cover 15, with its temperature sensing surface facing the terminal block 6. The temperature detection device 21 can be an NTC thermistor, a thermocouple, or an infrared temperature sensor.

[0046] This invention provides a low-voltage cable branch box system, including a control module and a low-voltage cable branch box. The control module includes a data receiving unit, a data analysis unit, and an alarm output unit. The data receiving unit is used to receive real-time data sent by a live detection device and a temperature detection device 21. The data analysis unit is used to determine whether the real-time data exceeds a preset threshold or whether liveness is detected. The alarm output unit is used to send alarm information to the operation and maintenance terminal when the preset threshold is exceeded.

[0047] Understandably, the data receiving unit is communicatively connected to the live detection device (such as the voltage tester 18) and the temperature detection device 21 in the branch box, receiving detection data in real time. The communication method can be wired connection or wireless communication such as G, LoRa, Wi-Fi, etc.

[0048] The data analysis unit analyzes and processes the received real-time data to determine whether it exceeds a preset threshold or whether a charge is detected. The data analysis unit can employ existing technologies as needed to analyze and process the real-time data.

[0049] When the data analysis unit determines that the data is abnormal, such as excessive temperature or detected electricity, the alarm output unit automatically generates alarm information and sends the alarm information to the handheld mobile APP of the operation and maintenance personnel, the monitoring center, or the audible and visual alarm via the network.

[0050] When a preset threshold is exceeded or a live signal is detected, the alarm output unit immediately sends an alarm message to the maintenance terminal. The message includes the specific branch box number and circuit number at the fault location, the fault type (overheating / live), and a timestamp. The system upgrades individual branch boxes into intelligent terminals, enabling remote centralized monitoring of power distribution lines. Maintenance personnel can monitor the operating status of each branch box without being on-site; abnormal situations can be detected and accurately located promptly, improving maintenance efficiency and power supply reliability.

[0051] Therefore, the low-voltage cable branch box and system of the present invention can improve heat dissipation efficiency and reduce the risk of electric shock without compromising the sealing performance.

[0052] The phase change heat conduction plate 7, phase change heat conduction pad 9, phase change heat conduction pad 9, capacitive induction measuring device, test pen 18, temperature detection device 21 and other components involved in the above embodiments are all products and electrical components using existing technology. The electrical connection and control methods between them and the control module are all existing technology and will not be described in detail.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A low-voltage cable branch box comprising a box body, an inner cavity of the box body being provided with a busbar and a terminal arranged on a front surface of the busbar, characterized in that: It also includes a heat dissipation device, which includes a phase change heat conduction plate and a finned radiator. The phase change heat conduction plate is disposed on the back of the busbar, and the finned radiator is disposed on the outer wall of the housing. The phase change heat conduction plate passes through the housing wall and is connected to the finned radiator.

2. A low voltage cable terminal box according to claim 1, characterized in that: The heat dissipation device also includes a phase change thermally conductive pad, which is disposed between the terminal block and the busbar.

3. A low voltage cable terminal box according to claim 2, characterized in that: The inner cavity of the enclosure is provided with a cable bracket, which includes a crossbeam and a vertical beam. The vertical beam is arranged on the inner side wall of the enclosure along the vertical direction of the enclosure. The vertical beam is provided with a plurality of first mounting holes. The two ends of the crossbeam are respectively arranged on the first mounting holes on the two oppositely arranged vertical beams. The crossbeam is provided with a plurality of second mounting holes. The phase change heat conduction plate is arranged on the crossbeam.

4. A low voltage cable terminal box according to claim 1, characterized in that: A visible insulating cover is detachably installed on the busbar, and the visible insulating cover covers the connection between the terminal block and the busbar.

5. A low voltage cable terminal box according to claim 4, characterized in that: The busbar is provided with a first mounting groove, which is adapted to the plug-in part of the visible insulating cover.

6. A low voltage cable terminal box according to claim 4, characterized in that: The visible insulating cover has heat dissipation channels.

7. A low voltage cable terminal box according to claim 4, characterized in that: A live-line detection device is installed inside the visible insulating cover. The live-line detection device is used to detect whether there is leakage at the connection between the terminal block and the busbar. The live-line detection device is arranged opposite to the terminal block.

8. A low voltage cable terminal box according to claim 7, characterized in that: The live detection device includes a test pen, a second mounting slot, a spring, and a resistor. The second mounting slot is disposed on the inner wall of the visible insulating cover. One end of the spring is connected to the test pen, and the other end is connected to the second mounting slot. The test end of the test pen abuts against the terminal block, and the non-test end of the test pen is connected to the resistor, which is grounded.

9. A low voltage cable terminal box according to claim 7, characterized in that: A temperature detection device is installed on the inner wall of the visible insulating cover.

10. A low-voltage cable branch box system, characterized in that: The system includes a control module and a low-voltage cable branch box as described in claim 9. The control module includes a data receiving unit, a data analysis unit, and an alarm output unit. The data receiving unit is used to receive real-time data sent by the live detection device and the temperature detection device. The data analysis unit is used to determine whether the real-time data exceeds a preset threshold or whether liveness is detected. The alarm output unit is used to send alarm information to the maintenance terminal when the preset threshold is exceeded.

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