Independent grounding system suitable for fusion device and construction method thereof

Abstract

The invention discloses an independent grounding system suitable for a fusion device and a construction method of the independent grounding system, and the system comprises a strong noise grounding grid and a weak noise grounding grid which are physically and electrically isolated from each other. The strong-noise ground screen is in radial connection to serve high-interference equipment such as a magnet power supply; the weak noise ground net is connected with a weak current system through tree topology and is further divided into interference ground, clean ground and protection ground. The system is formed by combining a deep well ion grounding body and a traditional grounding electrode, and a ground level protector is arranged between two ground nets to prevent potential counterattack. According to the application, a safe and reliable grounding system is provided for the fusion device by arranging strong and weak noise independent grounding grids which are physically and electrically isolated. According to the system, ground potential lifting caused by strong current interference can be avoided, the problems of equipment breakdown, data distortion and the like are effectively prevented, the laying area is reduced through the deep well grounding technology, and the electromagnetic compatibility and the operation stability are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering grounding technology, specifically to an independent grounding system suitable for fusion devices and its construction method. Background Technology

[0002] The current national standards and specifications generally adopt a common grounding device for the grounding of electrical intelligent systems, in which various grounding types such as lightning protection grounding, AC working grounding, DC working grounding, and protective grounding share a common grounding device.

[0003] A fusion device is a large-scale plasma physics device consisting of a main unit, support structure, magnets, high-power power supply, diagnostics, control, and data acquisition and processing systems. Under normal operating conditions, to provide sufficient magnetic confinement, the magnet power supply generates high voltages of tens of kilovolts and high currents of hundreds of kiloamperes. In the case of a shared grounding system, this often leads to equipment and instrument breakdown and damage, and the data from the fusion diagnostic system may become distorted or malfunction.

[0004] Furthermore, existing conventional outdoor grounding grids typically employ the method of burying horizontal and vertical grounding electrodes, which requires a considerable building area to meet the grounding resistance value of the fusion device. This will have a significant impact on the land use and implementation of the project. Summary of the Invention

[0005] This invention provides an independent grounding system suitable for fusion devices, which solves the problem of electromagnetic interference to weak electrical systems caused by the drastic rise in ground potential of the high-voltage system when existing fusion devices use a shared grounding system.

[0006] This invention is achieved through the following technical solution:

[0007] In a first aspect, this application provides an independent grounding system suitable for fusion devices, comprising:

[0008] A high-noise grounding grid is used to provide grounding for the high-power systems in fusion devices that generate large currents, high voltages, and rapidly changing electromagnetic noise.

[0009] Low-noise grounding grid is used to provide grounding for low-voltage systems in fusion devices that are sensitive to electromagnetic interference;

[0010] The high-noise grounding grid and the low-noise grounding grid are two independent grounding grids that are physically and electrically isolated from each other.

[0011] A further optimized solution is that the laying paths of the grounding conductor connected to the high-noise grounding grid and the grounding conductor connected to the low-noise grounding grid are separated indoors, and the grounding conductor is covered with an insulating sheath.

[0012] A further optimized solution is that the high-noise grounding grid and the high-voltage system equipment it serves are connected in a radial manner; the low-noise grounding grid and the low-voltage system equipment it serves are connected in a tree topology.

[0013] A further optimized solution is that the grounding conductor used to connect the high-noise grounding grid is a copper busbar, and the surface of the copper busbar outside the connection terminals is covered with a polyimide film insulation layer.

[0014] A further optimized solution is that the low-noise grounding grid further includes three functional grounding areas:

[0015] Interference-free, used to connect the vacuum chamber and support structure of the fusion device;

[0016] Cleanly, it is used to connect the diagnostic system, control system, data acquisition system, and signal processing system of the fusion device;

[0017] Protective ground is used to connect the cabinets and pipes of the fusion device as a protective ground.

[0018] A further optimized solution is that the high-noise grounding grid and / or the low-noise grounding grid are composed of a combination of deep-well ion grounding electrode and traditional grounding electrode.

[0019] A further optimized scheme is as follows: the deep well ion grounding electrode includes a deep well ion grounding rod and ion backfill material filling the surrounding area; the traditional grounding electrode includes a horizontally laid grounding flat steel and a copper-clad steel grounding electrode driven vertically into the ground.

[0020] A further optimized solution is to connect a ground-level protector between the high-noise grounding grid and the low-noise grounding grid; the ground-level protector is configured to: maintain electrical isolation between the two grounding grids under normal operating conditions, and quickly conduct in the event of a lightning strike or fault condition to temporarily connect the two grounding grids to achieve voltage equalization.

[0021] A further optimized solution is that the high-power system includes a magnet power supply, which includes at least one of a quasi-steady-state coil power supply, a field-cutting coil power supply, and a θ-pinch coil power supply;

[0022] The low-voltage system includes at least one of the following: device host, diagnostic system, control system, and data acquisition and processing system.

[0023] Secondly, this application provides a method for constructing an independent grounding system for a fusion device as described in any one of claims 1-9; the method includes the following steps:

[0024] Plan and set up independent and physically and electrically isolated high-noise grounding grids and low-noise grounding grids;

[0025] The high-noise grounding grid and the low-noise grounding grid are constructed using a combination of grounding electrodes;

[0026] A copper busbar is used as the grounding conductor of the high-noise grounding grid and is connected to the high-power system equipment of the fusion device in a radial connection manner; at the same time, a tree-like topology connection is used to connect the low-noise grounding grid to the low-power system equipment of the fusion device; wherein, the grounding conductors connected to the two grounding grids are separated from each other on the laying path and are covered with an insulating sheath.

[0027] Insulation is performed between the high-voltage system components and the low-voltage system components on the main unit of the device, and the working grounds of the two are respectively led to the corresponding high noise ground grid and low noise ground grid.

[0028] A ground-level protector is installed between the high-noise grounding grid and the low-noise grounding grid.

[0029] After completing all grounding connections, a systematic inspection and testing are performed to verify the grounding resistance value, path isolation effect, and ground-level protection device function, ultimately completing system integration. Compared with existing technologies, this invention has the following advantages and beneficial effects:

[0030] This invention provides an independent grounding system for the stable and reliable operation of a fusion device by setting up physically and electrically isolated high-noise grounding grids and low-noise grounding grids. This avoids continuous short circuits and grounding faults within the device, arcing caused by unexpected disconnections of large inductive circuits, stray currents caused by plasma interruption currents, and induced currents caused by changing magnetic fields, thus achieving safety, reliability, and electromagnetic compatibility of the system grounding. This grounding system effectively reduces the risk of equipment and instruments being damaged by breakdown; provides a clean electromagnetic environment for the control and diagnostic systems, resolving data distortion and malfunction issues; and reduces the area required for outdoor grounding grid installation. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0032] Figure 1 This is a layout diagram of a high-noise grounding system provided in an embodiment of this application;

[0033] Figure 2 This is a layout diagram of a low-noise grounding system provided in an embodiment of this application;

[0034] Figure 3A grounding grid layout diagram for an independent grounding system suitable for a fusion device, provided in the embodiments of this application;

[0035] Figure 4 The grounding grid construction diagram for an independent grounding system suitable for fusion devices is provided in the embodiments of this application.

[0036] In the diagram: 10, high-noise grounding grid; 20, low-noise grounding grid; 21, interference ground; 22, clean ground; 23, protective ground. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0038] To address the technical problems of electromagnetic interference to weak current systems caused by the drastic rise in ground potential of the high-voltage system when using a shared grounding system in existing fusion devices, and the excessive footprint of traditional grounding grids, this invention provides an independent grounding system suitable for fusion devices.

[0039] This application provides an independent grounding system for fusion devices, consisting of two physically and electrically isolated independent grounding grids: a high-noise grounding grid 10 and a low-noise grounding grid 20. The magnet power supply for the fusion device has high voltage, large current, and rapidly changing waveforms. Therefore, to ensure compatibility between systems, a separate grounding grid, called the high-noise grounding grid 10, is provided for the magnet power supply. A separate grounding grid, called the low-noise grounding grid 20, is provided for low-voltage signals such as diagnostic, acquisition, and control signals. The high-noise grounding grid 10 is dedicated to providing grounding for high-voltage systems (such as the magnet power supply) in the fusion device that generate large currents, high voltages, and rapidly changing electromagnetic noise; the low-noise grounding grid 20 is used to provide grounding for low-voltage systems sensitive to electromagnetic interference (such as diagnostic, control, and data acquisition systems).

[0040] Example 1

[0041] The following is a construction scheme for an independent grounding system suitable for fusion devices provided in this embodiment.

[0042] The high-noise grounding grid 10 is primarily used for grounding the magnet power supply. The magnet power supply comprises a quasi-steady-state coil power supply, a field-cutting coil power supply, and a theta-pinch coil power supply, with voltages reaching tens of kilovolts and currents reaching hundreds of kiloamperes, and waveform variations on the order of μs. Therefore, the magnet power supply itself, and its impact on the surrounding environment, generate significant interference. During discharge, the magnet power supply substantially raises the grounding grid voltage.

[0043] Considering the soil resistivity at the site is approximately 150 Ω·m, the simplified calculation formula for the power frequency grounding resistance of the artificial grounding electrode in the soil is as follows: It is estimated that the total area of ​​the grounding grid required to meet the grounding resistance of the fusion device is large, but the limited open space on site cannot meet this requirement. Therefore, this invention adopts a combination of deep-well ion grounding electrodes and traditional grounding electrodes to meet the grounding resistance requirements within the limited construction site. The independent grounding grid consists of deep-well ion grounding rods, ion backfill material, horizontal grounding flat steel, and vertical copper-clad steel grounding electrodes. The deep-well ion grounding rods are driven to a depth of no less than 20 meters. The ion backfill material uses highly conductive ionized materials (such as graphite / bentonite mixture) with a filling density ≥1.8 g / cm³ to enhance ion diffusion efficiency. The horizontal grounding flat steel is buried at a depth of no less than 0.8 meters and is connected to the vertical electrode by exothermic welding.

[0044] The specific construction structure of the grounding grid is as follows: Figure 4 As shown.

[0045] Considering the skin effect of current, the power system grounding conductor uses a copper busbar structure, connected radially to the independent grounding grid. Except for the connection terminal area, the copper busbar structure needs to be wrapped with polyimide film for insulation. The high-noise grounding system has independent grounding conductors, used for radial grounding connections to the switching power supply, quasi-steady-state power supply, and θ-pinch charger power supply, as shown below. Figure 1 As shown, the θ-pinch power supercapacitor is connected to the high-noise grounding system grounding grid using a trunk-type grounding method.

[0046] The low-noise grounding grid 20 is mainly used for grounding main units, supports, diagnostics, control, data acquisition and processing, etc. Because the low-noise grounding grid 20 involves a large number of devices, the low-noise grounding system adopts a tree topology, such as... Figure 2 As shown. Each subsystem is connected to the low-noise grounding network 20 through an independent grounding conductor, forming a complete grounding network. The low-noise grounding network 20 is further divided into three functional grounding areas: interference ground 21, used to connect the vacuum chamber and supporting structure; clean ground 22, used to connect systems with extremely high electromagnetic environment requirements, such as diagnostics, control, acquisition, and signal processing; and protective ground 23, used for protective grounding of cabinets, pipes, etc. Among them, the clean ground 22 area is further divided into a dedicated grounding sub-area for diagnostic equipment, which adopts a double-layer shielding isolation structure and an independent grounding conductor.

[0047] Insulation is applied between the high-voltage and low-voltage system components on the main unit to isolate the induced current generated by the high-voltage system from the low-voltage system. The working grounds of the high-voltage and low-voltage systems are connected to two separate independent grounding grids to ensure that the low-voltage system has a relatively clean and independent zero potential. The high-noise grounding grid 10 and the low-noise grounding grid 20 are maintained at a distance of at least 20 meters in outdoor installations. The relative positions of the grounding grids are as follows: Figure 3As shown, different laying paths and insulation sheaths are also adopted for the indoor grounding wire to avoid the ground potential of the control and diagnostic system (weak current) being raised by the magnet power system (high voltage) during device operation.

[0048] A multi-layer shielding isolation structure is adopted between the high-voltage system and the low-voltage system. The high-voltage cable uses a metal shielding layer and is grounded to the high noise grounding network 10, while the low-voltage signal line uses a twisted pair shielded cable and is grounded to the low noise grounding network 20. The grounding point of the shielding layer is simplified to avoid ground loop interference.

[0049] Because different independent grounding grids can generate high and low potential differences under special circumstances such as lightning strikes or magnet power supply failures, potential backflash may occur between equipment or systems. Therefore, ground-level protectors are added between different grounding grids. Under normal circumstances, the two independent grounding grids are insulated from each other and do not interfere with each other. In the event of a lightning strike or fault, the ground-level protector quickly conducts, changing the two independent grounding grids from their original isolated state to a temporary electrical connection state. Thus, voltage equalization and equipotential are achieved, avoiding equipment damage and personal safety risks. The ground-level protector is a surge protector (SPD) with a response time ≤25ns. Its operating voltage is set to be more than 1.5 times the 20 kV power frequency voltage of the weak noise grounding grid to avoid false triggering. It conducts instantaneously when the potential difference between the two grounding grids exceeds 5 kV to achieve voltage equalization.

[0050] Example 2

[0051] The basic architecture of this embodiment is the same as that of Embodiment 1. The difference lies in the fact that the construction details of the grounding grid can be adjusted according to specific site conditions. In cases where site conditions are more demanding and horizontal space is extremely limited, the configuration of the grounding electrodes can be further optimized. For example, the installation depth and number of deep-well ion grounding electrodes can be increased, and the laying range of horizontal grounding flat steel can be reduced accordingly. This maximizes the saving of land area while meeting the same grounding resistance requirements.

[0052] Example 3

[0053] The basic architecture of this embodiment is the same as that of Embodiment 1. The difference lies in that the functional zoning of the low-noise grounding grid 20 can be more refined. For certain special diagnostic devices in the fusion device that are extremely sensitive to electromagnetic interference, a dedicated diagnostic device grounding sub-area with stricter shielding and isolation measures can be further divided within the clean ground 22 area to achieve more refined and targeted grounding management and further improve the anti-interference capability of the low-voltage system.

[0054] This invention primarily provides an independent grounding system for the stable and reliable operation of fusion devices, avoiding continuous short circuits and grounding faults, arcing caused by unexpected disconnections of large inductive circuits, stray currents caused by plasma interruption currents, and induced currents caused by changing magnetic fields. This ensures the safety, reliability, and electromagnetic compatibility of the system grounding. This grounding system effectively reduces the risk of equipment and instruments being damaged by breakdown; provides a clean electromagnetic environment for control and diagnostic systems, resolving data distortion and malfunction issues; and reduces the area required for outdoor grounding grid installation.

[0055] The key innovation of this invention lies in its in-depth analysis of the operating conditions of various systems in a fusion device, the adoption of an independent grounding design for both strong and weak currents, and the matching of radial and tree-like grounding connection methods to the characteristics of different equipment. Deep-well grounding technology solves the problem of low-resistance grounding within a limited space, and the innovative introduction of a ground-level protector eliminates the potential risk of potential backflash between independent grounding grids. This systematically solves the problems of poor electromagnetic compatibility, equipment vulnerability, data distortion, and excessive grounding grid footprint inherent in fusion devices operating under a shared grounding mode.

[0056] Example 4

[0057] This embodiment provides a method for constructing an independent grounding system for a fusion device, including the following steps:

[0058] Step S1: Grounding network planning and isolation setup: Based on the electromagnetic noise characteristics of each system in the fusion device, plan and set up independent strong noise grounding network 10 and weak noise grounding network 20. The strong noise grounding network 10 is used to connect the magnet power system. The weak noise grounding network 20 adopts a tree topology structure and is divided into three functional grounding areas: interference ground 21, clean ground 22 and protective ground 23. The distance between the two grounding networks in the outdoor ground is not less than 20 meters.

[0059] Step S2: The strong noise grounding grid 10 and the weak noise grounding grid 20 are constructed by combining deep well ion grounding bodies with traditional grounding electrodes. The deep well ion grounding body includes a deep well ion grounding rod and ion backfill material filled around it. The traditional grounding electrode includes a horizontally laid grounding flat steel and a copper-clad steel grounding electrode driven vertically into the ground.

[0060] Step S3: For the strong noise grounding grid 10, copper busbars are used as grounding conductors and connected to each component of the magnet power supply in a radial connection manner; for the weak noise grounding grid 20, grounding conductors are independently led out from its grounding busbars and connected to the corresponding equipment of the interference ground 21, clean ground 22 and protective ground 23 in a trunk connection manner. The laying paths of the grounding conductors connected to the strong noise grounding grid 10 and the grounding conductors connected to the weak noise grounding grid 20 are separated in the room, and the grounding conductors are covered with an insulating sheath.

[0061] Step S4: On the main unit of the device, insulation treatment is performed between the high-voltage system components and the low-voltage system components, and their working grounds are respectively led to the high noise grounding grid 10 and the low noise grounding grid 20. A ground protection device is connected between the high noise grounding grid 10 and the low noise grounding grid 20. The ground protection device is configured to keep the two grounding grids electrically isolated under normal operating conditions and to quickly conduct in the event of lightning strike or fault conditions.

[0062] Step S5: After completing all grounding connections, conduct a systematic inspection and test to verify whether the grounding resistance values ​​of each independent grounding grid meet the requirements, ensure that the grounding paths of the strong and weak current systems are completely isolated, and that the grounding protection device functions normally.

[0063] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An independent grounding system suitable for fusion devices, characterized in that, include: A high-noise grounding grid is used to provide grounding for the high-power systems in fusion devices that generate large currents, high voltages, and rapidly changing electromagnetic noise. Low-noise grounding grid is used to provide grounding for the low-voltage systems in fusion devices that are sensitive to electromagnetic interference; The high-noise grounding grid and the low-noise grounding grid are two independent grounding grids that are physically and electrically isolated from each other.

2. The independent grounding system for fusion devices according to claim 1, characterized in that, The grounding conductor connected to the high-noise grounding grid and the grounding conductor connected to the low-noise grounding grid are laid separately in the indoor environment, and the grounding conductor is covered with an insulating sheath.

3. The independent grounding system for fusion devices according to claim 1, characterized in that, The high-noise grounding grid is connected to the high-power system equipment it serves in a radial manner; the low-noise grounding grid is connected to the low-power system equipment it serves in a tree topology.

4. The independent grounding system for fusion devices according to claim 3, characterized in that, The grounding conductor used to connect the high-noise grounding grid is a copper busbar, and the surface of the copper busbar outside the connection terminals is covered with a polyimide film insulation layer.

5. The independent grounding system for fusion devices according to claim 1, characterized in that, The low-noise grounding grid further includes three functional grounding areas: Interference-free, used to connect the vacuum chamber and support structure of the fusion device; Cleanly, it is used to connect the diagnostic system, control system, data acquisition system, and signal processing system of the fusion device; Protective ground is used to connect the cabinets and pipes of the fusion device as a protective ground.

6. The independent grounding system for fusion devices according to claim 1, characterized in that, The high-noise grounding grid and / or the low-noise grounding grid are composed of a combination of deep-well ion grounding electrode and traditional grounding electrode.

7. The independent grounding system for fusion devices according to claim 6, characterized in that, The deep well ion grounding electrode includes a deep well ion grounding rod and ion backfill material filling the surrounding area; the conventional grounding electrode includes a horizontally laid grounding flat steel and a copper-clad steel grounding electrode driven vertically into the ground.

8. The independent grounding system for fusion devices according to claim 1, characterized in that, A grounding protector is connected between the high-noise grounding grid and the low-noise grounding grid; the grounding protector is configured to: maintain electrical isolation between the two grounding grids under normal operating conditions, and quickly conduct in the event of a lightning strike or fault, so as to temporarily connect the two grounding grids to achieve voltage equalization.

9. The independent grounding system for fusion devices according to claim 1, characterized in that, The high-power system includes a magnet power supply, which comprises at least one of a quasi-steady-state coil power supply, a field-cutting coil power supply, and a θ-pinch coil power supply. The low-voltage system includes at least one of the following: device host, diagnostic system, control system, and data acquisition and processing system.

10. A construction method, characterized in that, A method for constructing an independent grounding system suitable for a fusion device as described in any one of claims 1-9; the construction method includes the following steps: Plan and set up independent and physically and electrically isolated high-noise grounding grids and low-noise grounding grids; The high-noise grounding grid and the low-noise grounding grid are constructed using a combination of grounding electrodes; A copper busbar is used as the grounding conductor of the high-noise grounding grid and is connected to the high-power system equipment of the fusion device in a radial connection manner; at the same time, a tree-like topology connection is used to connect the low-noise grounding grid to the low-power system equipment of the fusion device; wherein, the grounding conductors connected to the two grounding grids are separated from each other on the laying path and are covered with an insulating sheath. Insulation is performed between the high-voltage system components and the low-voltage system components on the main unit of the device, and the working grounds of the two are respectively led to the corresponding high noise ground grid and low noise ground grid. A ground-level protector is installed between the high-noise grounding grid and the low-noise grounding grid. After completing all grounding connections, a systematic inspection and testing are conducted to verify the grounding resistance value, path isolation effect, and ground-level protection device function, ultimately completing system integration.

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