Self-driven current limiting equipment
By using the self-driven current limiting device to automatically trip the circuit breaker when the short-circuit current surges, the stability and timeliness problems of the current limiting device under the impact of short-circuit current are solved, and a fast response and stable current limiting effect is achieved.
Patent Information
- Application Number
- CN202422756376.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2034-11-12
AI Technical Summary
Existing current limiting devices are not stable enough under short-circuit current shocks, and the timeliness of current limiting operations is poor. They require multiple components and complex control processes, resulting in long response times.
A self-driven current limiting device is used, including a reactor and a self-driven device. By utilizing the characteristics of short-circuit current surge, the moving contact and the static contact are automatically opened through the cooperation of the vacuum interrupter, pull rod, repulsion disk and main coil to achieve the current limiting effect.
It improves the response timeliness of the current limiting device, reduces the number of components and the control process, ensures that the circuit is quickly disconnected in the event of a short circuit fault, has good stability, and automatically resumes normal operation after the circuit fault is handled.
Smart Images
Figure CN223401465U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of current limiting devices, and in particular to a self-driven current limiting device. Background Art
[0002] Transformers are a crucial piece of power transmission and transformation equipment in power systems. The safety and reliability of transformer operation directly impacts the safety of the power grid. Improving the operational reliability of power transformers is crucial to the safe and reliable operation of the entire power grid. In recent years, with the rapid development of the national economy and the continuous improvement of residents' living standards, urban power loads have continued to rise. Civilian transformers are one of the primary outlets for consuming electricity in the power grid system.
[0003] When a load short circuit occurs in the circuit system of the power grid, the current in the circuit system (i.e., short-circuit current) will increase sharply. The short-circuit current is generally about ten times the rated current. The short-circuit current has a huge impact on electrical equipment such as transformers, generators, circuit breakers, and transmission lines. The impact of the short-circuit current seriously affects the safe operation of power transformers.
[0004] Traditional short-circuit current suppression devices require internal energy storage units, independent control circuits, and control chips, resulting in a large number of components. Due to the current flowing between these components, coupling effects may occur. Therefore, the stability of the related current limiting devices needs to be further improved. Furthermore, short-circuit current data collection, data analysis, data feedback, system determination, issuance of current limiting instructions, and execution of current limiting actions are required. The time required from fault occurrence to execution of current limiting operations is long, and the timeliness of circuit protection needs to be improved. Utility Model Content
[0005] In order to improve the timeliness of circuit opening of a current limiting device, the present application provides a self-driven current limiting device.
[0006] This application provides a self-driven current limiting device, which adopts the following technical solution:
[0007] A self-driven current limiting device, comprising a reactor and a self-driven device, wherein the self-driven device comprises a vacuum interrupter, a pull rod, a repulsion disk, and a main coil; a static contact and a moving contact are provided in the vacuum interrupter, and the contact and separation of the moving contact and the static contact respectively realize the closing and opening of the circuit;
[0008] The moving contact is directly or indirectly arranged on the pull rod, and the moving contact is movably arranged in the vacuum interrupter. The repulsion disk is directly or indirectly arranged on the pull rod. When current flows through the main coil, the repulsion disk can be repelled to cause the repulsion disk to be displaced. The main coil and the moving contact are electrically connected, the input end of the inductor is electrically connected to the main coil, and the output end of the inductor is electrically connected to the static contact.
[0009] A reactor is essentially a resistor with a large resistance. After the current passes through the reactor, part of the electrical energy is converted into heat energy and consumed by the reactor, while the other part of the electrical energy continues to be transmitted along the conductive medium. Therefore, the current value flowing out of the reactor is reduced, thereby achieving a current limiting effect.
[0010] Through the above technical solution, during the normal and stable operation of the circuit, the static contact and the moving contact are in contact with each other, and the current is preferentially conducted through the path where the static contact and the moving contact have smaller impedance. At this time, the inductor is bypassed, the current flowing through the inductor is small, the energy consumption is also small, and the repulsive force generated by the main coil on the repulsion disk is also relatively small, which is not enough to push the repulsion disk to move vertically upward, and the static contact and the moving contact remain in the closed state.
[0011] When a circuit fault occurs, the current value surges, that is, a short-circuit current is generated. The value of the short-circuit current is much greater than the normal current value. At this time, the current flowing through the main coil increases accordingly, and the magnetic field generated by the main coil increases accordingly. The repulsion disk generates an induced current and generates a magnetic field that repels the main coil. Under the mutual repulsion between the magnetic field generated by the main coil and the magnetic field generated by the repulsion disk, the repulsion disk drives the pull rod and the moving contact to move upward, and the moving contact and the static contact are disconnected. At this time, the short-circuit current can only be conducted along the inductor to the load end, thereby achieving the current limiting effect.
[0012] Of course, it is also possible to provide a larger current to the main coil by sensing the signal generated by the short-circuit current, thereby driving the repulsion disk and the moving contact to move upward to complete the opening of the circuit breaker, thereby achieving the effect of current limiting.
[0013] After the circuit fault is processed, the short-circuit current returns to normal and the current value decreases. At this time, the magnetic field generated by the main coil is insufficient to maintain the height position of the repulsion disk. The repulsion disk falls back downward, causing the moving contact and the static contact to complete the closing, and the circuit returns to normal operation.
[0014] This technical solution can directly complete the opening of the moving contact and the static contact by utilizing the characteristic of a surge in short-circuit current when a circuit fault occurs. There is no need to collect data, analyze data, provide data feedback, make system judgments, issue current limiting instructions, or execute current limiting actions, thereby effectively improving the timeliness of the circuit opening of the current limiting device.
[0015] In a preferred example, the present application can be further configured as follows: it also includes a holding mechanism, which is used to maintain the disconnected state of the moving contact and the static contact; the holding mechanism includes a secondary coil, one end of the secondary coil is electrically connected to the inductor, and the other end of the secondary coil is electrically connected to the main coil, the magnetic flux directions of the main coil and the secondary coil are consistent, and the main coil and the secondary coil are located on the same side of the repulsion disk.
[0016] Through the above technical solution, after the short-circuit fault is processed, the short-circuit current gradually returns to the normal current value. In the process of the current value gradually decreasing, the current flows through the main coil and the auxiliary coil, and the magnetic flux directions of the main coil and the auxiliary coil are consistent.
[0017] Therefore, although the magnetic field of the main coil is gradually weakening, the secondary coil still has a co-directional magnetic field of a certain field strength. That is to say, the magnetic fields of the main coil and the secondary coil are superimposed on each other, which can maintain the repulsion disk at a certain height, so that the moving contact and the static contact remain separated, ensuring the stability of the opening.
[0018] In a preferred example, the present application may be further configured as follows: the current may be a short-circuit current generated by a circuit fault.
[0019] Through the above technical solution, a large magnetic field is applied to the main coil through the short-circuit current, pushing the repulsion disk upward to complete rapid opening.
[0020] In a preferred example, the present application may be further configured as follows: the current may be the current provided by an energy storage element built into or external to the current limiting device, and the energy storage element is used to supply power to the main coil.
[0021] Through the above technical solution, the current supplied to the main coil can be the current provided by the energy storage element. The current provided by the energy storage element can complete the opening action of the moving contact and the static contact by using only the signal of a surge in the short-circuit current value as the trigger source.
[0022] In summary, this application has the following beneficial technical effects:
[0023] 1. When the circuit is operating normally, the current limiting device operates in a low impedance state, resulting in less energy loss, which is beneficial to saving power resources;
[0024] 2. When a short-circuit fault occurs, the system automatically drives the repulsion disk upward by utilizing the characteristic of a sharp increase in the short-circuit current value, completing the opening action of the moving and static contacts. This eliminates the need for data collection, data analysis, data feedback, system determination, issuance of current limiting instructions, and execution of current limiting actions, effectively improving the timeliness of circuit opening of the current limiting device.
[0025] 3. After the circuit fault is resolved, the current value decreases and the repulsion disk falls back, causing the moving contact and the static contact to close, and the circuit automatically resumes normal operation without manual operation. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application, mainly illustrating the structure of the reactor and the self-driving device.
[0027] Description of reference numerals:
[0028] 1. Reactor; 21. Vacuum interrupter; 211. Moving contact; 212. Static contact; 22. Pull rod; 23. Repulsion disk; 24. Main coil; 3. Auxiliary coil; 4. Insulation support tube; 51. Upper flange; 52. Lower flange. DETAILED DESCRIPTION
[0029] The following is combined with Figure 1 This application is described in further detail.
[0030] An embodiment of the present application discloses a self-driven current limiting device.
[0031] Refer to the attached Figure 1 As shown, a self-driven current limiting device includes a reactor 1, a self-driven device, an insulating support tube 4, an upper flange 51 and a lower flange 52.
[0032] Refer to the attached Figure 1 As shown, upper flange 51 and lower flange 52 are used to connect this device to other equipment. Upper flange 51 is mounted on the top of insulating support tube 4, while lower flange 52 is mounted on the bottom of insulating support tube 4. Reactor 1 is disc-shaped and has a high resistance. Some of the current flowing through reactor 1 is converted into heat energy, which is consumed by reactor 1. Reactor 1 is mounted on the outer wall of insulating support tube 4, while the self-driving device is located inside insulating support tube 4.
[0033] Refer to the attached Figure 1 As shown, the self-propelled device includes a vacuum interrupter 21, a pull rod 22, a repulsion disk 23, and a main coil 24. The pull rod 22 is arranged vertically, and the repulsion disk 23, main coil 24, and vacuum interrupter 21 are arranged in order from top to bottom within the insulating support tube 4. The repulsion disk 23 is fixedly connected to the pull rod 22, and the pull rod 22 passes through the middle of the main coil 24. To simplify the drawing, the relevant supporting structure of the main coil 24 is not shown.
[0034] Refer to the attached Figure 1As shown, a static contact 212 and a moving contact 211 are provided in the vacuum interrupter 21. The moving contact 211 is located directly above the static contact 212. The contact and separation of the moving contact 211 and the static contact 212 can respectively realize the closing and opening of the circuit. The moving contact 211 is directly or indirectly provided on the pull rod 22. The moving contact 211 is movably provided in the vacuum interrupter 21 along the vertical direction. The repulsion disk 23 is directly or indirectly provided on the pull rod 22. When current flows through the main coil 24, the repulsion disk 23 can be repelled, causing the repulsion disk 23 to be displaced. The main coil 24 and the moving contact 211 are electrically connected. The input end of the reactor 1 is electrically connected to the main coil 24. The output end of the reactor 1 is electrically connected to the static contact 212.
[0035] Refer to the attached Figure 1 As shown, the self-driven current-limiting device further includes a holding mechanism for maintaining the disconnected state of the moving contact 211 and the static contact 212. The holding mechanism includes a secondary coil 3, which is disposed within an insulating support cylinder 4. One end of the secondary coil 3 is electrically connected to the reactor 1, and the other end of the secondary coil 3 is electrically connected to the main coil 24. The magnetic flux directions of the main coil 24 and the secondary coil 3 are consistent, and the main coil 24 and the secondary coil 3 are located directly below the repulsion disk 23.
[0036] Refer to the attached Figure 1 As shown, one end of the main coil 24 is electrically connected to the auxiliary coil 3, and the end of the main coil 24 close to the auxiliary coil 3 is electrically connected to the moving contact 21, that is, the typical connection point of the moving contact 21 is located between the main coil 24 and the auxiliary coil 3. The moving contact 21 and the main coil 24 can be connected through a flexible connection. Figure 1 Not shown in the figure.
[0037] Refer to the attached Figure 1 As shown, the "current" in the above "current can pass through the repulsive disk 23 when current flows through the main coil 24" can be a short-circuit current caused by a circuit fault.
[0038] The implementation principle of this embodiment is: during normal operation of the circuit, the static contact 212 and the moving contact 211 are in contact with each other, and the current is preferentially conducted through the path where the static contact 212 and the moving contact 211 with smaller impedance are located. At this time, the inductor 1 is bypassed, the current flowing through the inductor 1 is small, the power consumption is also small, and the repulsive force generated by the main coil 24 on the repulsion disk 23 is also relatively small, which is not enough to push the repulsion disk 23 to move vertically upward, and the static contact 212 and the moving contact 211 maintain the closed state.
[0039] When a circuit fault occurs, the current value surges, and the short-circuit current generated is much larger than the normal current value. At this time, the current flowing through the main coil 24 increases accordingly, and the magnetic field generated by the main coil 24 increases accordingly. The repulsion disk 23 generates an induced current and generates a magnetic field that repels the main coil 24. Under the mutual repulsion between the magnetic field generated by the main coil 24 and the magnetic field generated by the repulsion disk 23, the repulsion disk 23 drives the pull rod 22 and the moving contact 211 to move upward, and the moving contact 211 and the static contact 212 are opened. At this time, the short-circuit current is conducted along the inductor 1 to the load end, thereby achieving the current limiting effect.
[0040] After the current decreases, the repulsive force of the secondary coil 3 on the repulsive disk 23 and the repulsive force of the main coil 24 on the repulsive disk 23 can still maintain the repulsive disk 23 at a certain height due to the superposition of the two, so that the moving contact 211 and the static contact 212 remain separated, ensuring the stability of the opening.
[0041] After the circuit fault is processed, the short-circuit current returns to normal. At this time, the magnetic field generated by the main coil 24 and the auxiliary coil 3 is insufficient to maintain the height of the repulsion disk 23. The repulsion disk 23 falls downward, causing the moving contact 211 and the static contact 212 to complete the closing, and the circuit resumes normal operation.
[0042] Refer to the attached Figure 1 As shown, in another embodiment, the “current” in the above-mentioned “current flowing through the main coil 24 can pass through the repulsive disk 23 ” can be the current provided by an energy storage element built into or external to the current limiting device, and the energy storage element is used to supply power to the main coil 24 .
[0043] The implementation principle of this embodiment is as follows: the power supply to the main coil 24 in this device can also be performed by the energy storage element. The energy storage element executes the instruction to supply power to the main coil 24 through the characteristic of the surge of induced current, so that the main coil 24 generates a strong magnetic field, repels the repulsion disk 23, and causes the repulsion disk 23 to move upward, completing the opening of the moving contact 211 and the static contact 212. At this time, the inductor 1 is connected to complete the current limiting.
[0044] After the circuit fault is processed, the energy storage element executes the instruction to cut off the power to the main coil 24 through the characteristic of the sudden drop of the induced current, and the repulsion disk 23 falls back, completing the closing of the moving contact 211 and the static contact 212, and the circuit resumes normal operation.
[0045] The above two embodiments both directly or indirectly utilize the characteristics of current surge, especially the solution described in the embodiment of directly utilizing short-circuit current. There is no need to perform data collection, data analysis, data feedback, system judgment, issuance of current limiting instructions and execution of current limiting actions in sequence, which effectively improves the timeliness of circuit disconnection of the current limiting device.
[0046] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application in turn. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.
Claims
1. A self-driven current limiting device, characterized in that: The invention comprises a reactor (1) and a self-driving device, wherein the self-driving device comprises a vacuum interrupter (21), a pull rod (22), a repulsive disk (23) and a main coil (24); a static contact (212) and a moving contact (211) are provided in the vacuum interrupter (21); the contact and separation of the moving contact (211) and the static contact (212) can respectively realize the closing and opening of the circuit; The moving contact (211) is directly or indirectly arranged on the pull rod (22), and the moving contact (211) can be movably arranged in the vacuum arc chamber (21). The repulsion disk (23) is directly or indirectly arranged on the pull rod (22). When current flows through the main coil (24), the repulsion disk (23) can be repelled, causing the repulsion disk (23) to be displaced. The main coil (24) and the moving contact (211) are electrically connected, the input end of the reactor (1) is electrically connected to the main coil (24), and the output end of the reactor (1) is electrically connected to the static contact (212).
2. A self-driven current limiting device according to claim 1, characterized in that: The invention also includes a holding mechanism, which is used to maintain the disconnected state of the movable contact (211) and the static contact (212); the holding mechanism includes a secondary coil (3), one end of the secondary coil (3) is electrically connected to the reactor (1), and the other end of the secondary coil (3) is electrically connected to the main coil (24), the magnetic flux directions of the main coil (24) and the secondary coil (3) are consistent, and the main coil (24) and the secondary coil (3) are located on the same side of the repulsion disk (23).
3. The self-driven current limiting device according to claim 1, characterized in that: The current may be a short-circuit current generated by a circuit fault.
4. A self-driven current limiting device according to claim 1, characterized in that: The current may be a current provided by an energy storage element built into or external to a current limiting device, and the energy storage element is used to supply power to the main coil (24).