A direct current detection device

Abstract

The application discloses a direct current detection device, and relates to the field of current detection.The device comprises an insulating shell, left and right connecting terminals arranged on the two sides of the insulating shell, an electric wire, a deformation spring, a conductive inner frame arranged in the insulating shell, a measuring shell and a sliding rheostat.The left connecting terminal is connected with one end of the deformation spring through the electric wire, the other end of the deformation spring extends into the conductive inner frame, the deformation spring is electrically connected with the conductive inner frame, and the right connecting terminal is connected with the conductive inner frame through the electric wire.A magnetic piston is arranged in the measuring shell in a lifting mode, the measuring shell is connected with the conductive inner frame through an insulating porcelain sleeve, a sliding sheet is arranged on the sliding rheostat, one end of the sliding sheet away from the sliding rheostat is in sliding fit with the outer wall of the measuring shell, and the magnetic piston drives the sliding sheet to slide through magnetic force.The deformation spring is connected with the magnetic piston through a transmission rope.The application reduces the cost of detecting the hidden danger of direct current.

Description

Technical Field

[0001] This application relates to the field of current change detection, and in particular to a DC current detection device. Background Technology

[0002] With the rapid development of new energy technologies, the installed capacity of new energy power generation forms such as wind power and photovoltaic power generation continues to climb. The electricity generated by these new energy power generation systems often needs to be transmitted efficiently through DC transmission systems. As the scale of new energy grid connection continues to expand, the voltage level of DC transmission systems is also increasing. For example, in the power transmission projects of some large-scale wind power bases and photovoltaic power plants, DC transmission technology with voltage levels of ±800kV or even higher has been widely adopted.

[0003] In high-voltage DC transmission systems, measuring potential DC current hazards is crucial. It not only helps control the power output of the transmission system and ensures efficient and stable power transmission, but also allows for real-time monitoring of system operation, timely detection of potential faults, and ensures safe and reliable system operation. However, current DC current measurement faces numerous challenges.

[0004] Currently, commonly used high-voltage DC current measurement devices mostly employ photocurrent transformers and zero-flux current transformers. Taking a ±800kV UHVDC transmission project as an example, the cost of a single photocurrent transformer measurement device can reach tens of thousands of yuan. Such high costs significantly increase the investment in DC transmission system construction, limiting the wider application of DC transmission technology. Furthermore, because DC current lacks periodic changes in direction and magnitude, it cannot be measured simply and efficiently using the principle of electromagnetic induction like alternating current. Therefore, there is an urgent need to invent a new detection device for detecting potential problems with DC current. Summary of the Invention

[0005] In order to detect potential problems with direct current, this application provides a direct current detection device.

[0006] The DC current detection device provided in this application adopts the following technical solution:

[0007] A DC current detection device includes an insulating shell, a left terminal and a right terminal disposed on both sides of the insulating shell, a wire, a deformation spring, a conductive inner frame disposed inside the insulating shell, a measuring shell, and a sliding rheostat. The left terminal is connected to one end of the deformation spring via the wire, and the other end of the deformation spring extends into the conductive inner frame, and the deformation spring and the conductive inner frame are electrically connected. The right terminal is connected to the conductive inner frame via the wire. A magnetic piston is vertically mounted inside the measuring shell, and the measuring shell is connected to the conductive inner frame via an insulating ceramic sleeve. A slider is disposed on the sliding rheostat, and the end of the slider away from the sliding rheostat slides against the outer wall of the measuring shell. The magnetic piston drives the slider to slide by magnetic force. The end of the deformation spring away from the wire is connected to the magnetic piston via a transmission rope.

[0008] By adopting the above technical solution, the deformation spring is made of shape memory alloy. The deformation spring deforms proportionally to the current, i.e., it undergoes longitudinal expansion and contraction, thereby driving the transmission rope to move. The transmission rope drives the magnetic piston to move, and the magnetic piston drives the slider to move through magnetic force, thus changing the resistance value of the sliding rheostat. The sliding rheostat is connected to an external resistance meter, and the change in resistance is detected to detect the change in current on the main line, thereby facilitating the elimination of potential hazards. The insulation effect of the insulating porcelain sleeve and the pull rope can achieve effective electrical insulation and isolation between the high-voltage side current and the low-voltage side measurement part. Since the system is a purely mechanical system and the cost of shape memory alloy material is not high, the equipment cost of a single system can be controlled below 10,000 yuan, which is less than a fraction of the cost of existing technologies, greatly reducing the cost of high-voltage DC current measurement systems.

[0009] Preferably, a fixed pulley is installed inside the conductive inner frame, the transmission rope is wound around the fixed pulley, and the end of the transmission rope connected to the deformation spring is horizontal.

[0010] By adopting the above technical solution and supporting the transmission rope with a fixed pulley, the movement of the transmission rope can be made smoother, ensuring the smooth movement of the magnetic piston.

[0011] Preferably, the magnetic piston has multiple balance holes.

[0012] By adopting the above technical solution, since the magnetic piston and the inner wall of the measuring shell are in frictional fit, the air pressure in the upper and lower spaces of the piston can be balanced through the balance hole, preventing the movement of the magnetic piston from being hindered by the pressure difference between the upper and lower spaces of the piston, thus affecting the measurement response speed.

[0013] Preferably, an active piston is slidably connected within the conductive inner frame, and a sealed space is formed between the active piston and the magnetic piston; one end of the deformation spring is connected to the active piston, and the end of the transmission rope is connected to the active piston.

[0014] By adopting the above technical solution, a sealed space is formed between the active piston and the magnetic piston. During the operation of the circuit, the large current will generate heat. The heat will cause the gas to expand in the sealed space, so that the transmission rope connecting the active piston and the magnetic piston is in a taut state. This will make the active piston, the transmission rope and the magnetic piston form a moving whole, thereby improving the movement response efficiency of the magnetic piston when the current changes.

[0015] Preferably, a flexible diaphragm is provided inside the conductive inner frame, the end of the flexible diaphragm is connected to the inner wall of the conductive inner frame, the end of the deformation spring is connected to the middle part of the flexible diaphragm, and the end of the transmission rope is connected to the middle part of the flexible diaphragm.

[0016] By adopting the above technical solution, the force required for the diaphragm to deform is smaller. When the deformation spring deforms and elongates or shortens, the middle part of the flexible diaphragm can easily deform, thereby driving the transmission rope to move and improving the measurement response.

[0017] Preferably, a horizontal conductive rod is provided at the top of the conductive inner frame, and a vertical conductive rod slides on the horizontal conductive rod. A sleeve ring is provided at the upper end of the vertical conductive rod, and the sleeve ring is sleeved on the horizontal conductive rod. A connecting wire is connected to the lower end of the vertical conductive rod, and the end of the deformation spring is connected to the connecting wire. A driving assembly for driving the horizontal conductive rod to slide is provided inside the conductive inner frame.

[0018] By adopting the above technical solution, when the current changes, the deformation spring extends and retracts longitudinally, driving the transmission rope to move. At the same time, the drive component drives the transverse guide rod to slide, so that the connecting wire moves with the change of the deformation spring, which can prevent the deformation spring from being pulled and damaged at the connecting wire.

[0019] Preferably, the surface of the fixed pulley is provided with a plurality of meshing teeth at intervals, and the transmission rope is provided with a toothed belt, the toothed belt meshing with the meshing teeth on the fixed pulley; the drive assembly includes a linkage gear and a linkage rack, a rotating shaft is coaxially fixed on the fixed pulley, the linkage gear is coaxially fixed on the rotating shaft, the linkage rack slides within the conductive inner frame, the linkage rack is fixedly connected to the vertical conductive rod, and the linkage gear meshes with the linkage rack.

[0020] By adopting the above technical solution, when the deformation spring extends or retracts longitudinally, the transmission rope drives the fixed pulley to rotate through the toothed shape. The fixed pulley synchronously drives the linkage gear to rotate, the linkage gear drives the linkage rack to slide, and the linkage rack then drives the vertical conductive rod to slide. This ensures that the connecting wire can move with the deformation of the deformation spring, preventing the deformation of the deformation spring from pulling the connecting wire and causing safety hazards.

[0021] In summary, this application includes at least one of the following beneficial technical effects:

[0022] The deformation spring is made of shape memory alloy, and its deformation is proportional to the current. When the deformation spring extends or retracts longitudinally, it drives the transmission rope and magnetic piston to move. The magnetic piston then moves the slider through magnetic force, changing the resistance of the sliding rheostat. The resistance meter detects the change in resistance to monitor the main line current, facilitating the identification of potential hazards. The insulating porcelain bushing and the pull rope provide electrical isolation between the high-voltage and low-voltage measurement sections. The system is a purely mechanical structure, and the shape memory alloy is inexpensive, allowing the cost of a single unit to be controlled within 10,000 yuan, which is only a fraction of the cost of existing technologies, significantly reducing the cost of high-voltage DC current measurement systems. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this application;

[0024] Figure 2 This is a schematic diagram of the overall structure of Embodiment 2 of this application;

[0025] Figure 3 This is a schematic diagram of the overall structure of Embodiment 3 of this application;

[0026] Figure 4 This is a schematic diagram of the overall structure of Embodiment 4 of this application;

[0027] Figure 5 This is a schematic diagram illustrating the structure of the sleeve ring in Embodiment 4 of this application;

[0028] Figure 6 This is a schematic diagram illustrating the main structure of the meshing teeth and toothed band in Embodiment 4 of this application;

[0029] Figure 7 This is a schematic diagram of the main driving component in Embodiment 4 of this application.

[0030] Reference numerals: 1. Insulating shell; 2. Left terminal; 3. Right terminal; 4. Wire; 5. Deformation spring; 6. Conductive inner frame; 61. Horizontal conductive rod; 62. Vertical conductive rod; 621. Sleeve ring; 622. Connecting wire; 7. Measuring shell; 71. Magnetic piston; 72. Balance hole; 8. Sliding rheostat; 81. Sliding plate; 9. Insulating porcelain sleeve; 10. Transmission rope; 101. Toothed belt; 20. Fixed pulley; 201. Meshing tooth; 202. Rotating shaft; 30. Active piston; 40. Flexible diaphragm; 50. Drive assembly; 501. Linkage gear; 502. Linkage rack; 5021. Sliding part; 5022. Rack part; 60. Sliding seat; 601. Sliding groove. Detailed Implementation

[0031] The following is in conjunction with the appendix Figures 1-7This application will be described in further detail.

[0032] This application discloses a DC current detection device.

[0033] Example 1

[0034] Reference Figure 1 The DC current detection device includes an insulating shell 1, a left terminal block 2, a right terminal block 3, a wire 4, a deformation spring 5, a conductive inner frame 6, a measuring shell 7, and a sliding rheostat 8; wherein the left terminal block 2 and the right terminal block 3 are respectively located on both sides of the insulating shell 1, and the conductive inner frame 6 is built inside the insulating shell 1.

[0035] The left terminal 2 is electrically connected to one end of the deformation spring 5 via wire 4, and the other end of the deformation spring 5 extends into the conductive inner frame 6 and forms an electrical connection with the conductive inner frame 6; the right terminal 3 is connected to the conductive inner frame 6 via wire 4, forming a current conduction path. The deformation spring 5 is made of shape memory alloy, and it undergoes longitudinal expansion and contraction when the current changes.

[0036] The measuring shell 7 is connected to the conductive inner frame 6 via an insulating ceramic sleeve 9. A magnetic piston 71 is mounted inside the measuring shell 7. A slider 81 is mounted on the sliding rheostat 8. The end of the slider 81 away from the rheostat 8 forms a sliding engagement with the outer wall of the measuring shell 7, and the magnetic piston 71 drives the slider 81 to slide along the outer wall of the measuring shell 7 via magnetic force. A groove is formed on the outer wall of the measuring shell 7, and the end of the slider 81 is T-shaped and slides in engagement with the groove. The sliding engagement structure between the slider 81 and the outer wall of the measuring shell 7 is relatively conventional and is not shown in the figure.

[0037] The end of the deformation spring 5 away from the wire 4 is connected to the magnetic piston 71 via the transmission rope 10, which is used to transmit the extension and retraction movement of the deformation spring 5 to the magnetic piston 71.

[0038] The deformation spring 5 is made of shape memory alloy, whose unique physical properties allow its deformation to be proportional to the change in current, thus producing predictable longitudinal stretching motion. This stretching motion drives the transmission rope 10 to produce linear displacement through mechanical transmission, and the movement of the transmission rope 10 synchronously drives the magnetic piston 71 to move in an directional manner within the measuring shell 7. A non-contact power transmission is formed between the magnetic piston 71 and the slider 81 using magnetic force; that is, the displacement of the magnetic piston 71 is synchronously moved by the magnetic force pulling the slider 81, ultimately changing the resistance value of the sliding rheostat 8 connected to the circuit. Since the sliding rheostat 8 and the external resistor form a closed detection loop, the resistor can capture the dynamic changes in resistance value in real time and deduce the current fluctuations in the main circuit based on a preset conversion model. This provides accurate monitoring data for timely identification of circuit abnormalities (such as overload, poor contact, and other potential risks), providing reliable technical support for hazard investigation. In practice, the technique of converting current fluctuations through resistance is quite conventional and will not be elaborated upon in this application.

[0039] In terms of electrical safety protection, the insulating porcelain bushing 9 and the transmission rope 10 together form a double insulation isolation system. The insulating porcelain bushing 9, with its excellent high-voltage resistance, effectively blocks the conduction path of high-voltage side current to low-voltage measurement parts; the transmission rope 10 is made of high-strength insulating material, further strengthening the electrical isolation effect between the high-voltage side and the low-voltage side measurement components, and avoiding safety accidents caused by high-voltage breakdown.

[0040] From an economic perspective, this system adopts a design concept that combines pure mechanical transmission with electromagnetic coupling. Its core functional components rely on cost-effective shape memory alloy materials, eliminating the high procurement costs of specialized components compared to existing measurement systems that depend on precision electronic components or optical sensors. Furthermore, the system's overall structure is simple, without complex integrated circuit design, significantly reducing the difficulty of manufacturing and subsequent maintenance. Therefore, the equipment cost of a single system can be strictly controlled to within 10,000 yuan, only one-fifth to one-tenth of the cost of traditional similar equipment. This significantly lowers the application threshold for high-voltage DC current measurement systems and possesses extremely high engineering promotion value.

[0041] A fixed pulley 20 is installed inside the conductive frame, and the transmission rope 10 is wound around the fixed pulley 20. The end of the transmission rope 10 connected to the deformation spring 5 is horizontal. The fixed pulley 20 achieves low-friction rotation through a bearing structure, and the contact surface between its groove and the transmission rope 10 is rounded to reduce lateral displacement and local stress concentration of the transmission rope 10 during movement. This support method can convert the sliding friction of the transmission rope 10 into the rolling friction of the fixed pulley 20, significantly reducing energy loss during transmission and ensuring that the transmission rope 10 moves linearly along the preset path without jamming.

[0042] The fixed pulley 20 makes the traction force of the transmission rope 10 more aligned with the axial direction of the magnetic piston 71, avoiding piston jamming caused by radial component force due to rope tilt, thus ensuring that the lifting and lowering movement of the magnetic piston 71 in the measuring shell 7 remains smooth and stable.

[0043] The magnetic piston 71 has multiple balancing holes 72. Considering that the magnetic piston 71 and the inner wall of the measuring housing 7 are friction-fitted, with a small gap between them, a pressure difference can easily form between the upper and lower spaces due to volume changes during the piston's reciprocating movement. By creating balancing holes 72 in the piston body, an airflow channel between the upper and lower spaces can be constructed: when the piston moves upward, the air pressure in the lower space increases, and gas flows through the balancing holes 72 to the upper space with lower air pressure; when the piston moves downward, compressed gas in the upper space is replenished to the lower space through the balancing holes 72, thereby dynamically balancing the air pressure values ​​on both sides of the piston and avoiding additional resistance caused by pressure differences. This ensures the current detection system's real-time capture capability of changes in the main circuit current and improves the overall dynamic response performance of the measurement.

[0044] If the magnetic piston 71 and the measuring shell 7 are fitted with a clearance, the magnetic piston 71 will tilt under the weight of the slider 81, affecting its normal lifting and lowering, resulting in a worse effect. In reality, the force generated by the extension and contraction of the deformation spring 5 is much greater than the frictional force between the magnetic piston 71 and the measuring shell 7, so it will not have a significant impact on the movement of the magnetic piston 71.

[0045] The implementation principle of the DC current detection device in this application embodiment is as follows: When the current changes significantly, the deformation spring 5 extends and retracts longitudinally, driving the transmission rope 10 and the magnetic piston 71 to move. The magnetic piston 71 then moves the slider 81 through magnetic force, changing the resistance of the sliding rheostat 8. The resistance meter detects the resistance change to monitor the main line current, facilitating the investigation of potential hazards. The insulating porcelain sleeve 9 and the pull rope achieve electrical isolation between the high-voltage side and the low-voltage side measurement parts. The system is a purely mechanical structure, and the shape memory alloy has low cost. The cost of a single set of equipment can be controlled within 10,000 yuan, which is only a fraction of that of the prior art, significantly reducing the cost of the high-voltage DC current measurement system.

[0046] Example 2

[0047] Reference Figure 2 The difference between this embodiment and embodiment 1 is that an active piston 30 is slidably connected inside the conductive inner frame 6, the magnetic piston 71 has no open balance hole, a closed space is formed between the active piston 30 and the magnetic piston 71, one end of the deformation spring 5 is connected to the active piston 30, and the end of the transmission rope 10 is connected to the active piston 30.

[0048] The cavity between the active piston 30 and the magnetic piston 71 is constructed as a sealed space. When the circuit is in operation, the large current flowing through it generates continuous heat. This causes the gas inside the cavity to expand due to the increased temperature, creating an outward thrust. Under this pressure, the transmission rope 10 between the active piston 30 and the magnetic piston 71 is tightened, eliminating any slack in the rope and forming a rigidly linked integrated structure between the active piston 30, the transmission rope 10, and the magnetic piston 71.

[0049] The advantage of this pre-tensioning mechanism is that when the current in the subsequent line changes (such as a sudden change or a gradual change), the driving force generated by the deformation spring 5 can be directly transmitted to the magnetic piston 71 through the taut transmission rope 10, avoiding the delay in force transmission caused by the slack of the rope and ensuring the response efficiency of the measurement.

[0050] Example 3

[0051] Reference Figure 3 The difference between this embodiment and embodiment 2 is that a flexible diaphragm 40 is provided inside the conductive inner frame 6, the end of the flexible diaphragm 40 is fixedly connected to the conductive inner frame 6, the end of the deformation spring 5 is connected to the middle part of the flexible diaphragm 40, and the end of the transmission rope 10 is connected to the middle part of the flexible diaphragm 40.

[0052] The diaphragm is made of a flexible material with a high elastic modulus (such as polytetrafluoroethylene or silicone rubber), and its structural design keeps the triggering force required for deformation at a low level. When the deformation spring 5 elongates or shortens due to changes in current, the resulting minute driving force can directly act on the central region of the flexible diaphragm 40. This region, due to its thinness and fixed edges, can undergo adaptive deformation under minimal external force. This characteristic allows the diaphragm to synchronously displace with the extension and contraction of the deformation spring 5 in real time, thereby driving the transmission rope 10 to move precisely through a rigid connection structure.

[0053] Compared to traditional rigid connection structures, the low-resistance deformation characteristics of the flexible diaphragm 40 significantly reduce the starting threshold of the transmission system, avoiding power transmission lag caused by gaps or frictional resistance between components. This design ensures that subsequent components such as the magnetic piston 71 and the slider 81 can respond more quickly to changes in current, ultimately improving the sensitivity and response accuracy of the entire measurement system to current fluctuations and providing more timely data feedback for real-time monitoring.

[0054] Example 4

[0055] Reference Figures 4-7The difference between this embodiment and embodiment 1 is that a horizontal conductive rod 61 is mounted on the top of the conductive inner frame 6, and a vertical conductive rod 62 is slidably connected to the horizontal conductive rod 61. A sleeve ring 621 is integrally formed at the upper end of the vertical conductive rod 62, and the sleeve ring 621 is slidably sleeved on the outer periphery of the horizontal conductive rod 61. A connecting wire 622 is connected to the lower end of the vertical conductive rod 62, and the end of the deformation spring 5 is electrically connected to the connecting wire 622. A driving assembly 50 for driving the horizontal conductive rod 61 to slide in the horizontal direction is provided inside the conductive inner frame 6.

[0056] When the main circuit current fluctuates, the shape memory alloy deformation spring 5 will extend and retract longitudinally in response to the current change, thereby driving the transmission rope 10 to move along a preset path. During this process, the drive assembly 50 synchronously drives the horizontal conductive rod 61 to slide horizontally. Through the sliding cooperation between the horizontal conductive rod 61 and the vertical conductive rod 62, the connecting wire 622 is adaptively displaced according to the direction and amplitude of the extension and retraction of the deformation spring 5. This method can eliminate the additional tension at the connection between the deformation spring 5 and the connecting wire 622. By compensating for the relative displacement of the two in real time, the stress generated by the extension and retraction of the deformation spring 5 is avoided from concentrating at the connection node, effectively preventing fatigue fracture or poor contact of the wire due to repeated pulling, thereby ensuring the continuity and stability of the current conduction path, extending the service life of the device and reducing the maintenance frequency.

[0057] The surface of the fixed pulley 20 has a number of meshing teeth 201 distributed at intervals along the circumference. A toothed belt 101 is connected to the transmission rope 10 accordingly. The toothed belt 101 and the meshing teeth 201 on the fixed pulley 20 form a meshing transmission engagement. This structure can effectively prevent relative slippage between the transmission rope 10 and the fixed pulley 20 through tooth meshing, thereby improving the accuracy of power transmission.

[0058] The drive assembly 50 consists of a linkage gear 501 and a linkage rack 502. A rotating shaft 202 is coaxially fixed on the fixed pulley 20. The linkage gear 501 is coaxially fixed with the rotating shaft 202, thus achieving synchronous rotation of the fixed pulley 20 and the linkage gear 501. The linkage rack 502 slides within the conductive inner frame 6. A sliding seat 60 is provided within the conductive inner frame 6, and a sliding groove 601 is formed on the sliding seat 60. The linkage rack 502 has a sliding part 5021 and a rack part 5022. The sliding part 5021 is T-shaped and matches the shape of the sliding groove 601. The sliding part 5021 of the linkage rack 502 slides and engages with the sliding groove 601. The end of the linkage rack 502 is fixedly connected to the vertical conductive rod 62. The linkage gear 501 meshes with the rack part 5022 of the linkage rack 502. In practice, the linkage rack 502 and other related components are all made of insulating material.

[0059] When the deformation spring 5 extends or retracts longitudinally, the transmission rope 10 rotates through the toothed belt 101 and the fixed pulley 20. The fixed pulley 20 synchronously drives the linkage gear 501 to rotate. The linkage gear 501 drives the linkage rack 502 to slide. The linkage rack 502 then drives the vertical conductive rod 62 to slide. This ensures that the connecting wire 622 can move with the deformation of the deformation spring 5, preventing the deformation of the deformation spring 5 from pulling the connecting wire 622 and causing safety hazards.

[0060] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A DC current detection device, characterized in that: The device includes an insulating outer shell (1), a left terminal (2) and a right terminal (3) disposed on both sides of the insulating outer shell (1), a wire (4), a deformation spring (5), a conductive inner frame (6) disposed inside the insulating outer shell (1), a measuring shell (7), and a sliding rheostat (8). The left terminal (2) is connected to one end of the deformation spring (5) via the wire (4), and the other end of the deformation spring (5) extends into the conductive inner frame (6), and the deformation spring (5) and the conductive inner frame (6) are electrically connected. The right terminal (3) is connected to the conductive inner frame (6) via the wire (4). A magnetic piston (71) is installed in the measuring shell (7) and moves up and down. The measuring shell (7) is connected to the conductive inner frame (6) via an insulating ceramic sleeve (9). The sliding rheostat (8) is provided with a slider (81), and the end of the slider (81) away from the sliding rheostat (8) is slidably engaged with the outer wall of the measuring shell (7). The magnetic piston (71) drives the slider (81) to slide by magnetic force. The end of the deformation spring (5) away from the wire (4) is connected to the magnetic piston (71) through the transmission rope (10). The deformation spring (5) is made of shape memory alloy. An active piston (30) is slidably connected in the conductive inner frame (6). A sealed space is formed between the active piston (30) and the magnetic piston (71). One end of the deformation spring (5) is connected to the active piston (30), and the end of the transmission rope (10) is connected to the active piston (30).

2. The DC current detection device according to claim 1, characterized in that: A fixed pulley (20) is installed inside the conductive inner frame (6), and the transmission rope (10) is wound around the fixed pulley (20). The end of the transmission rope (10) connected to the deformation spring (5) is horizontal.

3. The DC current detection device according to claim 2, characterized in that: The magnetic piston (71) has multiple balance holes (72).

4. The DC current detection device according to claim 1, characterized in that: The conductive inner frame (6) is provided with a flexible diaphragm (40), the end of the flexible diaphragm (40) is connected to the inner wall of the conductive inner frame (6), the end of the deformation spring (5) is connected to the middle part of the flexible diaphragm (40), and the end of the transmission rope (10) is connected to the middle part of the flexible diaphragm (40).

5. A DC current detection device according to claim 2, characterized in that: A horizontal conductive rod (61) is provided at the top of the conductive inner frame (6), and a vertical conductive rod (62) slides on the horizontal conductive rod (61). A sleeve ring (621) is provided at the upper end of the vertical conductive rod (62), and the sleeve ring (621) is sleeved on the horizontal conductive rod (61). A connecting wire (622) is connected to the lower end of the vertical conductive rod (62), and the end of the deformation spring (5) is connected to the connecting wire (622). A driving assembly (50) for driving the horizontal conductive rod (61) to slide is provided inside the conductive inner frame (6).

6. A DC current detection device according to claim 5, characterized in that: The fixed pulley (20) has a plurality of meshing teeth (201) spaced apart on its surface. The transmission rope (10) is provided with a toothed belt (101), which meshes with the meshing teeth (201) on the fixed pulley (20). The drive assembly (50) includes a linkage gear (501) and a linkage rack (502). A rotating shaft (202) is coaxially fixed on the fixed pulley (20). The linkage gear (501) is coaxially fixed on the rotating shaft (202). The linkage rack (502) slides within the conductive inner frame (6). The linkage rack (502) is fixedly connected to the vertical conductive rod (62), and the linkage gear (501) meshes with the linkage rack (502).

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