An active protection system for safe electricity use at construction sites

Abstract

This utility model relates to the field of electrical protection technology and discloses an active protection system for safe electricity use at construction sites. The system includes a power supply, a 1:1 isolation transformer, a TN-S system, an IT system, and a first three-phase electrical device. The power supply is coupled to the primary input terminal of the 1:1 isolation transformer via the TN-S system, and the secondary output terminal of the 1:1 isolation transformer is coupled to the first three-phase electrical device via the IT system. This utility model employs a TN-S system to ensure power supply distance and reliability, and introduces an IT system to ensure that in the event of a first single-phase ground fault, the system generates only a small current and issues an alarm, thereby significantly reducing the risk of electric shock at construction sites.

Description

Technical Field

[0001] This utility model relates to the field of electrical protection technology, specifically to an active protection system for safe electricity use at construction sites. Background Technology

[0002] TN-S system and IT system are two commonly used electrical protection systems on construction sites. For example... Figure 1 As shown, the TN-S system uses a three-phase five-wire system (L1, L2, L3, N, PE). In this system, the exposed conductive parts of the three-phase electrical equipment are connected to the neutral ground via the protective earth (PE) conductor. The PE conductor and the neutral conductor (N) are separate from the power supply end and are not combined throughout the system. Figure 2 As shown, in the IT system, the center point is not grounded or is grounded with a large resistance, and the exposed conductive parts of the three-phase electrical equipment are grounded through the PE grounding device.

[0003] In a TN-S system, when a ground fault occurs (e.g., the equipment casing becomes energized due to insulation failure), the fault current path is: power grid → phase line (L) → fault point → protective earth (PE) → return to power source. This path has extremely low impedance, approximating a short circuit, generating a very large short-circuit current. This will lead to an electrical fire risk: the lines will heat up rapidly and burn. If a person touches the energized casing, the current will flow through the person to the ground, causing electric shock. Because the fault current is extremely large, it is necessary to rely on overcurrent protection devices (such as circuit breakers and fuses) to trip instantaneously and quickly cut off the power supply to ensure personal and equipment safety.

[0004] In IT systems, when a ground fault occurs (e.g., the equipment casing becomes energized due to insulation failure), the fault current path is: power grid → phase line (L) → fault point → grounding resistance → system-to-ground distributed impedance (large resistance) → back to the power source, forming a series circuit. In a series circuit, voltage is distributed, and the smaller the resistance, the smaller the voltage. Therefore, during a ground fault, most of the voltage is distributed by the large resistance. When a person touches the casing of the faulty equipment, they are connected in parallel with the grounding resistance, resulting in extremely low voltage and significantly reducing the risk of electric shock. However, IT systems may experience leakage over long power supply distances, where the current forms a loop through the ground. Protection devices may not operate promptly, posing a safety hazard. Therefore, IT systems are not suitable for large-scale power supply. Utility Model Content

[0005] This utility model provides an active protection system for safe electricity use at construction sites, which can protect the lives of personnel using electricity at construction sites and significantly reduce the risk of electric shock at construction sites.

[0006] Therefore, the present invention provides the following technical solution: An active protection system for safe electricity use at construction sites includes a power supply, a 1:1 isolation transformer, a TN-S system, an IT system, and a first three-phase electrical device. The power supply is coupled to the primary input terminal of the 1:1 isolation transformer through the TN-S system, and the secondary output terminal of the 1:1 isolation transformer is coupled to the first three-phase electrical device through the IT system.

[0007] Optionally, the system further includes a residual current device (RCD) connected to the TN-S system, which disconnects the power supply when a leakage occurs on the TN-S system side.

[0008] Optionally, the residual current device (RCD) is used.

[0009] Optionally, the system further includes a three-level distribution box connected to the IT system to supply power to the first three-phase electrical equipment.

[0010] Optionally, the system further includes a second three-phase electrical device connected to the TN-S system.

[0011] Optionally, the system further includes an equipotential bonding body, which is connected to the 1:1 isolation transformer, the first three-phase electrical equipment, the second three-phase electrical equipment, and the three-level distribution box, and grounds the exposed conductive parts of the 1:1 isolation transformer, the first three-phase electrical equipment, the second three-phase electrical equipment, and the three-level distribution box.

[0012] Optionally, the system further includes an insulation monitor connected to the central processing unit. The insulation monitor is connected to the IT system, collects the insulation resistance signal of the IT system, and transmits the insulation resistance signal to the central processing unit. When the central processing unit detects that the insulation resistance signal is lower than a set threshold, it activates an audible and visual alarm and uploads the fault signal to the management platform to lock the faulty circuit.

[0013] Optionally, the insulation monitoring instrument is an IMD insulation monitoring instrument.

[0014] This utility model provides an active protection system for safe electricity use at construction sites, comprising a power supply end, a TN-S system, an isolation transformer, an IT system, electrical equipment, an insulation monitoring instrument, and an external module central control unit. In high-risk areas (metal cutting areas, rebar processing areas, and welding areas), the IT system is connected to the end of the TN-S system via the isolation transformer to achieve dual protection. The isolation transformer electrically isolates the TN-S system from the IT system. When a single-phase ground fault occurs in the electrical equipment, the ground capacitance current on the IT system side is extremely small, and the fault voltage is effectively clamped, significantly reducing the risk of electric shock. The insulation monitoring instrument monitors the insulation status in real time. Once an abnormality is detected, the central control unit immediately issues an early warning and cuts off the power supply, achieving active protection and improving the safety and reliability of electricity use at construction sites. Attached Figure Description

[0015] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0016] Figure 1 This is a schematic diagram of the TN-S system. Figure 2 This is a schematic diagram of the IT system structure; Figure 3 This is a schematic diagram of the active protection system for safe electricity use at construction sites, as described in a specific embodiment of this utility model. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0018] like Figure 3The diagram shown is a structural diagram of an active protection system for safe electricity use at construction sites, according to an embodiment of this utility model. This active protection system includes a power supply 1, a 1:1 isolation transformer 2, a three-stage distribution box 3, an insulation detector 4, three-phase electrical equipment a5, an equipotential bonding device 6, a residual current device 7, and three-phase electrical equipment b8. The power supply 1 supplies power to the three-stage distribution box 3 via a TN-S system, which in turn supplies power to the three-phase electrical equipment a5. The 1:1 isolation transformer 2 completely isolates the primary and secondary sides of the power grid. The secondary side output is connected to the IT system and then to the three-phase electrical equipment a5. The insulation detector 4 monitors the insulation status of the IT system to ground in real time; an IMD insulation detector can be used. The three-phase electrical equipment b8 is connected to the TN-S system. The equipotential bonding device 6 reliably connects the exposed conductive parts of the equipment to the grounding electrode, ensuring potential balance in fault conditions and preventing contact voltage hazards. The central control unit receives data from the insulation detector 4 in real time. When the insulation resistance is detected to be lower than the set threshold, the central control unit immediately activates an audible and visual alarm and uploads the fault signal to the management platform via the wireless communication module, while simultaneously locking the faulty circuit. In the event of a leakage current on the TN-S system side, the residual current device 7 cuts off the power supply within 0.1 seconds to ensure personnel safety. The residual current device 7 can be a residual current device (RCD). This system, through the combination of a dual grounding system and intelligent monitoring technology, achieves accurate prediction and graded response to electrical risks at the construction site, ensuring the reliability of continuous power supply to equipment and significantly improving the level of personal safety protection.

[0019] This invention employs a TN-S system to ensure power supply distance and reliability, and introduces an IT system to ensure that when the first single-phase ground fault occurs, the system generates only a small current and issues an alarm, thereby significantly reducing the risk of electric shock at the construction site.

[0020] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0021] The embodiments of this utility model have been described in detail above. Specific implementation methods have been used to illustrate this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and system of this utility model, and are merely some, not all, embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model. The content of this specification should not be construed as a limitation of this utility model. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An active protection system for safe electricity use at construction sites, characterized in that, The system includes a power supply, a 1:1 isolation transformer, a TN-S system, an IT system, and a first three-phase electrical device. The power supply is coupled to the primary input terminal of the 1:1 isolation transformer through the TN-S system, and the secondary output terminal of the 1:1 isolation transformer is coupled to the first three-phase electrical device through the IT system.

2. The active protection system for safe electricity use at construction sites according to claim 1, characterized in that, The system also includes a residual current device (RCD) connected to the TN-S system. When a leakage occurs on the TN-S system side, the RCD cuts off the power supply.

3. The active protection system for safe electricity use at construction sites according to claim 2, characterized in that, The residual current device (RCD) is used.

4. The active protection system for safe electricity use at construction sites according to claim 2, characterized in that, The system also includes a three-level distribution box, which is connected to the IT system and supplies power to the first three-phase electrical equipment.

5. The active protection system for safe electricity use at construction sites according to claim 4, characterized in that, The system also includes a second three-phase electrical device, which is connected to the TN-S system.

6. The active protection system for safe electricity use at construction sites according to claim 5, characterized in that, The system also includes an equipotential bonding body, which is connected to the 1:1 isolation transformer, the first three-phase electrical equipment, the second three-phase electrical equipment, and the three-level distribution box, and grounds the exposed conductive parts of the 1:1 isolation transformer, the first three-phase electrical equipment, the second three-phase electrical equipment, and the three-level distribution box.

7. The active protection system for safe electricity use at construction sites according to claim 1, characterized in that, The system also includes an insulation monitor connected to the central processing unit. The insulation monitor is connected to the IT system, collects the insulation resistance signal of the IT system, and transmits the insulation resistance signal to the central processing unit. When the central processing unit detects that the insulation resistance signal is lower than a set threshold, it activates an audible and visual alarm and uploads the fault signal to the management platform to lock the faulty circuit.

8. The active protection system for safe electricity use at construction sites according to claim 7, characterized in that, The insulation monitoring instrument used is an IMD insulation monitoring instrument.

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