Varistor for medium voltage capacitors
By designing a voltage-sensitive circuit breaker for brackets, detection arms, limit switches and pressure switches, the existing medium-voltage capacitor protection device has solved the problems of complex structure and poor control accuracy, and the safe exit of the capacitor in the event of a fault is achieved, ensuring that Grid safety.
Patent Information
- Application Number
- CN202110367626.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-04-06
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2041-04-06
AI Technical Summary
The protection device of existing medium-voltage capacitors has complex structure and poor control accuracy. It cannot effectively control circuit breakers when the capacitor fails, which poses a safety threat.
A voltage-sensitive circuit breaker including a bracket, detection arm, limit switch and pressure switch is designed. By detecting the expansion displacement of the capacitor, the limit switch and pressure switch are triggered, so that the capacitor can automatically or actively exit the power grid operation, adopting triple safety Protection mechanism.
It realizes the safe exit of the capacitor in the event of a fault, avoids safety threats caused by the fault, has a simple structure and accurate control, and avoids the safety risks caused by capacitor failure.
Smart Images
Figure CN113012935B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of capacitors, and in particular to a voltage-sensitive circuit breaker protector for a medium-voltage capacitor. Background Art
[0002] When the electrical equipment in the power system is in use, it will generate reactive power, which will reduce the efficiency of the power supply capacity. Appropriately adding capacitance to the power system can improve this problem. Square capacitors are a type of compensation equipment often used in power systems, which can compensate for reactive power or power factor in power systems. Since the inside of the capacitor shell is sealed, once the capacitor fails, it will generate a lot of heat, causing the shell to deform. In severe cases, it will cause the capacitor to explode, posing a threat to the surrounding environment, other equipment or the safety of operators. Therefore, it is very necessary to set up a capacitor protection device.
[0003] For the protection device of dry-type medium-voltage capacitors operating in 6kV and 10kV power systems, some existing technical solutions adopt a matching structure of explosion-proof lead grooves and protection wires, and the structure manufacturing and assembly are relatively complex and the control accuracy is poor, the processing cost is high, and the use effect is poor; in other existing technical solutions, an explosion-proof component is arranged on the capacitor, and a conductor for connecting the terminal is arranged in the middle of the explosion-proof component. When the capacitor fails during operation, gas expansion is generated, causing the outer shell to deform and break the conductor, thereby disconnecting the capacitor from the circuit, but the breaking capacity of this technical solution cannot be effectively controlled and the control accuracy is poor. Summary of the invention
[0004] In view of this, an object of the present invention is to provide a varistor circuit breaker for a medium voltage capacitor, which can automatically and safely shut down the capacitor from the power grid when a fault occurs inside the capacitor or the capacitor reaches the end of its service life, or can actively shut down the capacitor from the power grid.
[0005] In order to achieve the above object, the present invention provides a voltage-sensitive circuit breaker protector for a medium voltage capacitor, comprising:
[0006] A bracket, which is fixedly arranged above the capacitor;
[0007] A detection arm, comprising a first detection arm and a second detection arm, wherein the first detection arm is connected to one end of the bracket, and the second detection arm is connected to the other end of the bracket, and the first detection arm and the second detection arm are at a first predetermined distance from the capacitor in a horizontal direction;
[0008] A limit switch, which is fixedly arranged on the bracket, comprises a first limit switch and a second limit switch, wherein the first limit switch is close to one end of the bracket, and the second limit switch is close to the other end of the bracket;
[0009] A pressure switch is fixedly arranged on the mounting bracket, and the pressure switch is electrically connected to the first limit switch and the second limit switch.
[0010] Furthermore, a first connecting piece is formed at one end of the bracket, and the first detection arm is rotatably connected to the first connecting piece. A second connecting piece is formed at the other end of the bracket, and the second detection arm is rotatably connected to the second connecting piece.
[0011] Furthermore, a first limit seat close to one end of the bracket and a second limit seat close to the other end of the bracket are fixedly provided on the bracket, the first detection arm is connected to the first limit seat by a spring limit, and the second detection arm is connected to the second limit seat by a spring limit.
[0012] Further, the first limit switch is fixedly arranged on the inner side of the first limit seat, the first limit switch passes through the first limit seat and extends out of the outer side of the first limit seat, and the second limit switch is fixedly arranged on the inner side of the second limit seat, the second limit switch passes through the second limit seat and extends out of the outer side of the second limit seat.
[0013] Further, the first limit switch is at a second predetermined distance from the first detection arm in the horizontal direction, and the second limit switch is at a second predetermined distance from the second detection arm in the horizontal direction;
[0014] Furthermore, the first terminal of the first limit switch is connected to a wire, the second terminal of the first limit switch is connected to the third terminal of the pressure switch via a wire, the fourth terminal of the pressure switch is connected to the fifth terminal of the second limit switch via a wire, and the sixth terminal of the second limit switch is connected to a wire.
[0015] Furthermore, a wiring barrel is provided on one side of the bracket, and the first wiring terminal of the first limit switch is connected to the wire through the wiring barrel, and the sixth wiring terminal of the second limit switch is connected to the wire through the wiring barrel.
[0016] Further, when the lower end of the first detection arm is displaced 2 to 3 mm relative to the capacitor, the first limit switch is triggered, so that the normally closed contact of the first limit switch is disconnected;
[0017] When the lower end of the second detection arm is displaced 2 to 3 mm relative to the capacitor, the second limit switch is triggered, so that the normally closed contact of the second limit switch is disconnected.
[0018] Furthermore, when the pressure switch is actuated by pressure, the normally closed contacts of the pressure switch are disconnected.
[0019] Compared with the prior art, the voltage-sensitive circuit breaker protector for medium-voltage capacitors of the present invention can produce at least the following beneficial effects:
[0020] The present invention has a bracket fixedly arranged above the capacitor, and two limit switches and a pressure switch are fixedly arranged on the bracket. Two detection arms are respectively arranged on both sides of the capacitor and connected to both ends of the bracket. When the capacitor fails, it expands outward, causing the detection arm to displace 2 to 3 mm relative to the capacitor. The first detection arm and / or the second detection arm triggers the limit switch, so that the capacitor can be withdrawn from the power grid in a timely and safe manner; the present invention also has a pressure switch connected between the two limit switches, which can actively apply pressure to trigger the pressure switch, so that the capacitor can be withdrawn from the power grid. The present invention has no additional wiring or control unit, achieves triple safety protection, and has a simple structure and precise control, avoiding safety threats caused by capacitor failure. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0022] Figure 1 A schematic structural diagram of a voltage-sensitive circuit breaker protector for a medium-voltage capacitor provided in an embodiment of the present invention;
[0023] Figure 2 for Figure 1 A local enlarged view of point A in FIG.
[0024] Figure 3 A top view of a varistor circuit breaker protector for a medium voltage capacitor provided by an embodiment of the present invention;
[0025] Figure 4 for Figure 3 A local enlarged view of point B in FIG.
[0026] Figure 5 A side view of a voltage-sensitive circuit breaker protector for a medium-voltage capacitor provided by an embodiment of the present invention;
[0027] Figure 6 for Figure 5 A local enlarged view of point C in FIG.
[0028] Figure 7 A reactive power compensation circuit diagram provided by an embodiment of the present invention;
[0029] Figure 8 A control circuit diagram of a high-voltage three-phase contactor in a reactive power compensation circuit provided by an embodiment of the present invention;
[0030] Fig. 9A control circuit diagram of a relay in a high-voltage three-phase contactor provided in an embodiment of the present invention.
[0031] The above drawings include the following reference numerals:
[0032] 1. Capacitor; 10. Bracket; 11. First connecting piece; 12. Second connecting piece; 13. First limit seat; 14. Second limit seat; 15. Spring; 16. Wiring barrel; 21. First detection arm; 22. Second detection arm; 31. First limit switch; 311. First terminal; 312. Second terminal; 32. Second limit switch; 321. Fifth terminal; 322. Sixth terminal; 40. Pressure switch; 401. Third terminal; 402. Fourth terminal. DETAILED DESCRIPTION
[0033] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.
[0034] The present invention provides a voltage-sensitive circuit breaker protector for medium voltage capacitors. Figures 1 to 6 , including: a bracket 10, which is fixedly arranged above the capacitor 1; a detection arm, including a first detection arm 21 and a second detection arm 22, the first detection arm 21 is connected to one end of the bracket 10, and the second detection arm 22 is connected to the other end of the bracket 10, and the first detection arm 21 and the second detection arm 22 are at a first predetermined distance from the capacitor 1 in the horizontal direction; a limit switch, which is fixedly arranged on the bracket 10, including a first limit switch 31 and a second limit switch 32, the first limit switch 31 is close to one end of the bracket 10, and the second limit switch 32 is close to the other end of the bracket 10; a pressure switch 40, which is fixedly arranged on the mounting bracket 10, and the pressure switch 40 is electrically connected to the first limit switch 31 and the second limit switch 32.
[0035] Preferably, the first predetermined distance is not greater than 2-3 mm.
[0036] In this embodiment, a first connecting member 11 is formed at one end of the bracket 10, and a first detection arm 21 is rotatably connected to the first connecting member 11; a second connecting member 12 is formed at the other end of the bracket 10, and a second detection arm 22 is rotatably connected to the second connecting member 12.
[0037] Preferably, the first connecting member 11 and the second connecting member 12 are located below the bracket 10 in the horizontal direction.
[0038] Preferably, the first detection arm 21 and the second detection arm 22 are parallel to the side surface of the capacitor 1 with a larger area.
[0039] In this embodiment, the bracket 10 is fixedly provided with a first limit seat 13 near one end of the bracket 10 and a second limit seat 14 near the other end of the bracket 10, the first detection arm 21 is limitedly connected to the first limit seat 13 by a spring 15, and the second detection arm 22 is limitedly connected to the second limit seat 14 by a spring 15; the first limit switch 31 is fixedly provided on the inner side of the first limit seat 13, the first limit switch 31 passes through the first limit seat 13 and extends out of the first limit seat 13, the second limit switch 32 is fixedly provided on the inner side of the second limit seat 14, the second limit switch 32 passes through the second limit seat 14 and extends out of the second limit seat 14; the first limit switch 31 and the first detection arm 21 have a second predetermined distance in the horizontal direction, and the second limit switch 32 and the second detection arm 22 have a second predetermined distance in the horizontal direction;
[0040] Preferably, the second predetermined distance is smaller than the first predetermined distance.
[0041] In this embodiment, the first terminal 311 of the first limit switch 31 is connected to a wire, the second terminal 312 of the first limit switch 31 is connected to the third terminal 401 of the pressure switch 40 via a wire, the fourth terminal 402 of the pressure switch 40 is connected to the fifth terminal 321 of the second limit switch 32 via a wire, and a wire is connected to the sixth terminal 322 of the second limit switch 32.
[0042] In this embodiment, a wiring barrel 16 is provided on one side of the bracket 10 , and the first terminal 311 of the first limit switch 31 is connected to the wire through the wiring barrel 16 , and the sixth terminal 322 of the second limit switch 32 is connected to the wire through the wiring barrel 16 .
[0043] In this embodiment, when the lower end of the first detection arm 21 is displaced 2 to 3 mm relative to the capacitor 1, the upper end of the first detection arm 21 squeezes the spring 15 and triggers the first limit switch 31, so that the normally closed contact of the first limit switch 31 is disconnected; when the lower end of the second detection arm 22 is displaced 2 to 3 mm relative to the capacitor 1, the upper end of the second detection arm 22 squeezes the spring 15 and triggers the second limit switch 32, so that the normally closed contact of the second limit switch 32 is disconnected.
[0044] In this embodiment, when the pressure switch 40 is actuated by pressure, the normally closed contacts of the pressure switch 40 are opened.
[0045] For the working principle of the varistor circuit breaker protector for medium voltage capacitors provided by the present invention, please refer to Figures 7 to 9 , Figure 7 A reactive power compensation circuit diagram provided by an embodiment of the present invention, Figure 8 A control circuit diagram of a high-voltage three-phase contactor in a reactive power compensation circuit provided by an embodiment of the present invention, Fig. 9A control circuit diagram of a relay in a high-voltage three-phase contactor provided in an embodiment of the present invention, wherein three capacitors are connected in a star shape and are connected in series with a high-voltage three-phase reactor, and are connected to a 10kV power system through a high-voltage three-phase contactor, a high-voltage three-phase contactor coil is connected in series with a normally open contact of a relay and connected to a 220V power supply, a relay coil is connected in series with a first limit switch, a pressure switch, and a second limit switch and connected to a 24V DC power supply, and a 24V DC power supply is connected to a 220V power supply.
[0046] When the 24V DC power supply is powered on, the relay coil is energized, causing the normally open contacts of the relay to close, and the high-voltage three-phase contactor coil is energized, and then the normally open contacts of the high-voltage three-phase contactor are closed, connecting the capacitor to the 10kV power system, and the capacitor is put into operation to achieve reactive power compensation.
[0047] When a fault occurs during the operation of the capacitor, or when the capacitor reaches the end of its life after years of operation, the metallized film inside the capacitor will continue to break down, slowly producing smoke and gas, and the metallized film will become molten. As the smoke and gas continue to accumulate, the pressure inside the capacitor continues to increase, causing one side with a larger area and / or another side with a larger area of the capacitor to expand outward, and when the lower end of the first detection arm is displaced 2 to 3 mm relative to the capacitor, the first limit switch is triggered to disconnect its normally closed contact, and / or when the lower end of the second detection arm is displaced 2 to 3 mm relative to the capacitor, the second limit switch is triggered to disconnect its normally closed contact, causing the relay coil to lose power, the normally open contact of the relay to disconnect, the high-voltage three-phase contactor coil to lose power, and the normally open contact of the high-voltage three-phase contactor to disconnect, thereby ensuring that the capacitor is safely withdrawn from the power grid.
[0048] In addition, pressure can be applied to trigger the pressure switch, causing the relay coil to lose power, and then the high-voltage three-phase contactor coil to lose power, and the normally open contacts of the high-voltage three-phase contactor to be disconnected, ensuring that the capacitor is safely withdrawn from the power grid.
[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A voltage-sensitive circuit breaker protector for a medium voltage capacitor, characterized in that: include: A bracket (10) fixedly disposed above the capacitor (1); A detection arm, comprising a first detection arm (21) and a second detection arm (22), wherein the first detection arm (21) is connected to one end of the bracket (10), and the second detection arm (22) is connected to the other end of the bracket (10), and the first detection arm (21) and the second detection arm (22) are at a first predetermined distance from the capacitor (1) in a horizontal direction; A first connecting member (11) is formed at one end of the bracket (10), and the first detection arm (21) is rotatably connected to the first connecting member (11); a second connecting member (12) is formed at the other end of the bracket (10), and the second detection arm (22) is rotatably connected to the second connecting member (12); a limit switch, which is fixedly arranged on the bracket (10), comprising a first limit switch (31) and a second limit switch (32), wherein the first limit switch (31) is close to one end of the bracket (10), and the second limit switch (32) is close to the other end of the bracket (10); a pressure switch (40) fixedly disposed on the bracket (10), and the pressure switch (40) is electrically connected to the first limit switch (31) and the second limit switch (32); When the lower end of the first detection arm (21) is displaced 2 to 3 mm relative to the capacitor (1), the first limit switch (31) is triggered, causing the normally closed contact of the first limit switch (31) to open; When the pressure switch (40) is actuated by pressure, the normally closed contact of the pressure switch (40) is disconnected.
2. The voltage-sensitive circuit breaker protector according to claim 1, characterized in that: A first limit seat (13) close to one end of the bracket (10) and a second limit seat (14) close to the other end of the bracket (10) are fixedly arranged on the bracket (10); the first detection arm (21) is connected to the first limit seat (13) by means of a spring (15); and the second detection arm (22) is connected to the second limit seat (14) by means of a spring (15).
3. The voltage-sensitive circuit breaker protector according to claim 2, characterized in that: The first limit switch (31) is fixedly arranged on the inner side of the first limit seat (13), the first limit switch (31) passes through the first limit seat (13) and extends out of the outer side of the first limit seat (13), and the second limit switch (32) is fixedly arranged on the inner side of the second limit seat (14), the second limit switch (32) passes through the second limit seat (14) and extends out of the outer side of the second limit seat (14).
4. The voltage-sensitive circuit breaker protector according to claim 3, characterized in that: There is a second predetermined distance between the first limit switch (31) and the first detection arm (21) in the horizontal direction, and there is a second predetermined distance between the second limit switch (32) and the second detection arm (22) in the horizontal direction.
5. The voltage-sensitive circuit breaker protector according to claim 1, characterized in that: A first wiring terminal (311) of the first limit switch (31) is connected to a wire, a second wiring terminal (312) of the first limit switch (31) is connected to a third wiring terminal (401) of the pressure switch (40) via a wire, a fourth wiring terminal (402) of the pressure switch (40) is connected to a fifth wiring terminal (321) of the second limit switch (32) via a wire, and a wire is connected to a sixth wiring terminal (322) of the second limit switch (32).
6. The voltage-sensitive circuit breaker protector according to claim 5, characterized in that: A wiring barrel (16) is provided on one side of the bracket (10), a first wiring terminal (311) of the first limit switch (31) is connected to a wire through the wiring barrel (16), and a sixth wiring terminal (322) of the second limit switch (32) is connected to a wire through the wiring barrel (16).