Vacuum circuit breaker

Abstract

The present invention relates to a vacuum interrupter (20). The vacuum interrupter (20) may be installed in an interior space (12) of a housing (10) and penetrate the housing (10). The vacuum interrupter (20) includes a vacuum interrupter (210) and an interlocking mechanism (230). The interlocking mechanism (230) may include a piston (246) that provides a force capable of offsetting the self-closing force of the vacuum interrupter (210). The piston (246) may have a diameter larger than that of a drive rod (254) that penetrates the housing (10) and may have a diameter that is the same as or similar to the effective diameter of a bellows (224) in the vacuum interrupter (210).

Description

[Technical Field]

[0001] The present invention relates to a vacuum circuit breaker. [Background technology]

[0002] A vacuum circuit breaker is a circuit breaker that uses a vacuum as an arc-extinguishing medium (VI). It performs planned operations such as power transmission, reception, switching, and shutdown, and also automatically shuts off the power system quickly when a fault occurs in the power system.

[0003] This type of vacuum circuit breaker has a vacuum interrupting unit, the inside of which is a vacuum, installed in a housing filled with insulating gas at high or low pressure, and an operating unit located outside the housing performs operations to operate the vacuum interrupting unit.

[0004] However, the inside of the vacuum interrupter is a vacuum, and the pressure of the insulating gas inside the housing in which the vacuum interrupter is installed is greater than atmospheric pressure. Therefore, the movable rod of the vacuum interrupter is constantly subjected to a force that tries to move into the vacuum interrupter due to the pressure difference between the inside of the housing and the inside of the vacuum interrupter. This force is generally called a self-closing force.

[0005] In addition, an operating device for operating the movable rod of the vacuum interrupter is installed outside the housing, and a drive rod for transmitting the driving force of the operating device to the movable rod has no choice but to penetrate the housing. The drive rod is directly connected to the movable rod and is affected by the self-closing force, which causes a problem in that the self-closing force interferes with the operation of the movable rod and the drive rod.

[0006] In particular, the vacuum interrupter installed inside the housing is affected only by the pressure of the insulating gas inside the housing. The pressure of the insulating gas is added to the self-closing force, which acts in a direction to maintain the movable electrode of the vacuum interrupter in contact with the fixed electrode. This force can also change the magnitude of the operating force that separates the movable electrode from the fixed electrode using an actuator. In other words, if the pressure of the insulating gas inside the housing changes, the operating force of the actuator to satisfy the operating characteristics must also change, which causes a problem of complex actuator design.

[0007] Furthermore, while an environmentally friendly gas is used as the insulating gas, the pressure inside the housing increases, which increases the load on the bellows, posing a problem that a high-pressure bellows must be used.

[0008] Prior documents relating to such vacuum circuit breakers include Korean Patent Publication No. 10-2016-0048320, Korean Patent Publication No. 10-2017-0058637, and Korean Patent Registration No. 10-1060780. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to reduce the self-closing force by allowing the interlocking mechanism installed through the housing to be subjected to atmospheric pressure and the pressure inside the housing simultaneously.

[0010] Another object of the present invention is to maintain a constant target speed during the interruption operation in a vacuum circuit breaker. [Means for solving the problem]

[0011] According to a feature of the present invention for achieving the above object, the present invention provides a vacuum circuit breaker having a part located inside a housing and another part penetrating the housing, the vacuum circuit breaker being installed inside the housing, wherein a vacuum space in a vacuum state is formed inside the housing, and the vacuum circuit breaker has a fixed electrode in this vacuum space and a movable electrode that moves toward and away from the fixed electrode; a drive rod that is installed through the housing and transmits force for driving the movable electrode, and an interlocking mechanism that operates integrally with the drive rod and has a piston with an outer diameter larger than that of the drive rod.

[0012] The interlocking mechanism may further include a piston guide installed to penetrate the housing, and a guide body of the piston guide may include a rod through-hole through which the driving rod passes and which communicates with the outside of the housing, and a cylinder in which the piston is movably installed and which has a piston space open to the inside of the housing.

[0013] An airtight packing and a piston wear ring may be provided between the outer surface of the piston and the inner surface of the piston space.

[0014] A rod wear ring may be provided between the inner surface of the rod through-hole and the outer surface of the driving rod.

[0015] A movable rod is provided through the housing, one side of which is connected to the movable electrode and the other side of which is connected to the linking mechanism, and a bellows may seal the gap between the movable rod and the housing.

[0016] The effective diameter of the bellows and the outer diameter of the piston may have the same value.

[0017] A guide tube may be installed through the housing, the movable rod may be positioned through the guide tube, and the bellows may be installed between the guide tube and the movable rod.

[0018] An insulating rod made of an insulating material may be further provided to connect the movable rod and the piston of the linking mechanism.

[0019] A piston guide on which the piston and driving rod of the interlocking mechanism are installed is installed through the housing, and a mounting flange is formed around one side of the outer surface of a guide body that forms the skeleton of the piston guide, so that one side surface of the mounting flange can be in close contact with the outer surface of the housing.

[0020] A rod through-hole through which the driving rod passes is formed through the center of the guide body, and a cylinder having a cylinder space formed therein, one side of which communicates with the rod through-hole and the other side of which communicates with the internal space of the housing, may protrude toward the vacuum interrupter. [Effects of the Invention]

[0021] The vacuum circuit breaker according to the present invention can have at least one of the following effects.

[0022] In this invention, a vacuum circuit breaker is constructed, and an interlocking mechanism that penetrates the housing is provided with a piston with a diameter larger than that of the drive rod. The piston provides a force equivalent to the force acting due to the pressure of the insulating gas inside the housing minus the force acting due to atmospheric pressure outside the housing, thereby reducing the self-closing force of the vacuum circuit breaker. This has the effect of reducing the force required by the operating device to drive the movable electrode.

[0023] Furthermore, in the present invention, the diameter of the piston (or the diameter of the piston's airtight packing), which is subjected to the force due to the pressure of the insulating gas inside the housing and the force due to atmospheric pressure, is made the same as the effective diameter of the bellows, which is subjected to the self-closing force, so that the self-closing force is canceled out. This makes it possible to maintain a constant target speed during the circuit breaking operation. This has the effect of simplifying the design of the operating mechanism for operating the vacuum circuit breaker. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view showing a preferred embodiment of a vacuum interrupter according to the present invention installed in an enclosure. [Figure 2] 2 is an enlarged cross-sectional view showing a piston guide and related components in the embodiment shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a cross-sectional perspective view showing a piston guide and its surroundings constituting the embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view showing the configuration of a piston guide constituting the embodiment of the present invention. [Figure 5] 5 is an operational state diagram showing a current-carrying state in which the movable electrode is in contact with the drive electrode in the embodiment of the present invention. FIG. [Figure 6] 1 is an operational state diagram illustrating how pressures inside and outside the housing act on the piston in an embodiment of the present invention. [Figure 7] FIG. 7(a) is an explanatory diagram showing the pressure acting on the drive rod and bellows in the prior art, and FIG. 7(b) is an explanatory diagram showing the pressure acting on the drive rod, piston, and bellows in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, several embodiments of the present invention will be described in detail with reference to the drawings. When assigning reference numerals to components in each drawing, it should be noted that the same components are assigned the same numerals as much as possible even if they are displayed in different drawings. When describing the embodiments of the present invention, if it is determined that a detailed description of related known configurations or functions will hinder understanding of the embodiments of the present invention, the detailed description will be omitted.

[0026] Furthermore, when describing components of an embodiment of the present invention, terms such as "first," "second," "A," "B," "(a)," and "(b)" may be used. These terms are used to distinguish the component from other components. These terms do not limit the nature, order, or sequence of the components. When a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that another component may be "coupled," "coupled," or "connected" between each component.

[0027] As shown in the drawings, a vacuum circuit breaker 20 according to an embodiment of the present invention may be installed in a housing 10 having an internal space 12. The internal space 12 of the housing 10 may be filled with an insulating gas. The internal space 12 of the housing 10 may contain various components including the vacuum circuit breaker 20 according to the present embodiment, conductors, etc.

[0028] The vacuum circuit breaker 20 of this embodiment may include a vacuum circuit breaker 210 installed in the internal space 12 of the housing 10 , and an interlocking mechanism 230 installed to penetrate the housing 10 .

[0029] The exterior of the vacuum interrupter 210 may be formed by a housing 212. A vacuum space 214 may be formed inside the housing 212. The inside of the vacuum space 214 may be maintained at a vacuum. A fixed electrode 216 is provided on one side of the inside of the vacuum space 214. The fixed electrode 216 may be electrically connected to the outside of the housing 212.

[0030] A movable electrode 218 may be movably installed within the housing 212 so as to move toward and away from the fixed electrode 216. The movable electrode 218 contacts the fixed electrode 216 to connect the line, and separates from the fixed electrode 216 to disconnect the line. A movable rod 220 is connected to the movable electrode 218. The movable rod 220 is connected to an operator 260 via a linkage mechanism 230 (described later) and can operate the movable electrode 218 by receiving a driving force.

[0031] A guide tube 222 may be installed to penetrate the housing 212. The guide tube 222 may have a hollow cylindrical shape. The movable rod 220 may be installed to penetrate the inside of the guide tube 222.

[0032] A bellows 224 may be installed such that both ends are connected to one side of the movable rod 220 and the other side of the guide tube 222, respectively. The bellows 224 may have a pleated cylindrical shape as a whole. The bellows 224 may have a variable length. The bellows 224 may be installed between the movable rod 220 and the guide tube 222 and may isolate the interior of the housing 212 from the outside. That is, the bellows 224 may function to prevent the vacuum space 214 of the housing 212 from communicating with the outside while allowing the movable rod 220 to move while passing through the housing 212. The bellows 224 may have continuous pleats and may be expandable and contractible such that its length is variable. For example, the inner surface of one end of the bellows 224 may be coupled to the outer surface of one side of the movable rod 220, and the outer surface of the other end of the bellows 224 may be coupled to the inner surface of the guide tube 222.

[0033] The vacuum interrupter 210 may be fixed in the housing 10 by an insulating support 226. The insulating support 226 is fixed to one side of the internal space 12 of the housing 10 and serves to support the vacuum interrupter 210 and an interlocking mechanism 230, which will be described later.

[0034] The movable rod 220 and the piston 246 of the interlocking mechanism 230 may be connected by an insulating rod 228. The insulating rod 228 is made of an insulating material and can insulate the movable rod 220 from the piston 246, i.e., the interlocking mechanism 230.

[0035] The configuration of the interlocking mechanism 230 will now be described. The interlocking mechanism 230 includes a piston guide 232. The piston guide 232 may be installed to penetrate the housing 10. A piston 246 and a driving rod 254 are positioned to penetrate the piston guide 232 and can move back and forth linearly. In other words, the piston guide 232 serves to guide the movement of the piston 246 and the driving rod 254.

[0036] A guide body 234 may form the framework of the piston guide 232. The guide body 234 may have a cylindrical shape as a whole. The guide body 234 may have a mounting flange 236. The mounting flange 236 protrudes from surrounding one side edge of the guide body 234. One side surface of the mounting flange 236 may be in close contact with the outer surface of the housing 10, so that the piston guide 232 cannot be inserted into the housing 10 any more.

[0037] A rod through-hole 238 may be formed through the center of the piston guide 232 in the longitudinal direction. A driving rod 254 may be movably positioned in the rod through-hole 238. A ring channel 240 may be formed surrounding the inner surface of the rod through-hole 238. A rod wear ring 250, which will be described later, may be positioned in the ring channel 240.

[0038] The guide body 234 of the piston guide 232 may have a cylinder 242. A piston space 244 is formed inside the cylinder 242. The piston space 244 is connected to the rod through-hole 238. A piston 246 (described later) is installed in the piston space 244 and can move linearly back and forth. The piston space 244 may have a circular cross section. The piston space 244 may have the same cross section as the piston 246 (described later). Therefore, for example, if the cross section of the piston space 244 is rectangular, the cross section of the piston 246 may also be rectangular.

[0039] The piston 246 can move linearly back and forth within the cylinder 242. One surface of the piston 246 can be exposed to the internal space 12 of the housing 10 because the cylinder 242 is open to the internal space 12. The piston 246 has a diameter larger than the diameter of a drive rod 254, which will be described later.

[0040] One surface of the piston 246 may serve to receive the pressure of the internal space 12. The other surface of the piston 246 may serve to receive the atmospheric pressure outside the housing 10. Generally, since the pressure in the internal space 12 of the housing 10 is greater than the atmospheric pressure outside the housing 10, the piston 246 may have a tendency to move toward the outside of the housing 10.

[0041] The outer diameter of the piston 246 may be the same as or similar to the effective diameter of the bellows 224. This is to ensure that the pressure in the internal space 12 acting on the piston 246 is the same as or similar to the pressure in the internal space 12 acting on the bellows 224. Of course, the outer diameter of the piston 246 may be larger than the effective diameter of the bellows 224 to relatively reduce or eliminate the self-closing force.

[0042] A ring channel (not shown) is formed around the outer surface of the piston 246, and an airtight packing 248 may be installed in the ring channel. The airtight packing 248 serves to maintain airtightness. A piston wear ring 249 may be installed in one of the ring channels. The piston wear ring 249 may prevent wear due to metal surface contact between the piston 246 and the inner surface of the cylinder 242 and eccentricity during operation. The piston wear ring 249 may be installed on the inner surface of the cylinder 242 instead of the piston 246.

[0043] A rod wear ring 250 may be installed in the ring channel 240 on the inner surface of the rod through hole 238. The rod wear ring 250 may prevent wear due to metal surface contact between the rod through hole 238 and the drive rod 254 and eccentricity during operation. The rod wear ring 250 may also be installed on the outer surface of the drive rod 254.

[0044] An airtight packing 252 may be installed between the outer surface of the guide body 234 of the piston guide 232 and the inner surface of the through-hole of the housing 10. The airtight packing 252 may be installed on the guide body 234 or may be formed on the inner surface of the through-hole of the housing 10. The airtight packing 252 may prevent leakage of insulating gas from between the outer surface of the piston guide 232 and the housing 10.

[0045] A driving rod 254 extends from the piston 246 to the outside of the housing 10. The driving rod 254 may be formed integrally with the piston 246. The diameter of the driving rod 254 is smaller than the diameter of the piston 246. The driving rod 254 may be connected to an actuator 260. The driving rod 254 is connected to the actuator 260 and receives an operating force from the actuator 260 to control the operation of the movable rod 220, thereby moving the movable electrode 218 toward and away from the fixed electrode 216.

[0046] The use of the vacuum circuit breaker according to the present invention having the above-described configuration will now be described in detail.

[0047] The vacuum circuit breaker 20 of the present invention can function to connect and disconnect lines within the housing 10. As shown in Fig. 5, the fixed electrode 216 and the movable electrode 218 are in contact with each other to connect the lines, and when an emergency signal is provided, the movable electrode 218 is separated from the fixed electrode 216 by the operation of the operating device 260 to disconnect the lines. For example, Fig. 1 shows a state in which the movable electrode 218 is separated from the fixed electrode 216.

[0048] The movable electrode 218 can be separated from the fixed electrode 216 when the operator 260 pulls the driving rod 254 upward relative to the drawing. When the driving rod 254 is pulled, the piston 246 moves from one side of the cylinder 242 to the other side, i.e., toward the outside of the housing 10, and the insulating rod 228 connected to the piston 246 moves together. The movement of the insulating rod 228 causes the movable rod 220 to move linearly, and the movement of the movable rod 220 causes the movable electrode 218 to move linearly and be separated from the fixed electrode 216.

[0049] During this operation, a force may act on the piston 246, as shown in Fig. 6. As shown in Fig. 6, one side surface of the piston 246 is exposed to the interior space 12 of the housing 10. Therefore, the piston 246 is subjected to a pressure PI of the insulating gas in the interior space 12.

[0050] In addition, a rod wear ring 250 is installed in the rod through hole 238 of the piston guide 232, and atmospheric pressure P0 can act on the other surface of the piston 246 through the space between the inner surface of the rod through hole 238 and the driving rod 254. Therefore, the insulating gas pressure P1 inside the housing 10 and the atmospheric pressure P0 simultaneously act on the piston 246, generating a force substantially opposite to the self-closing force.

[0051] Meanwhile, a force can act on the components that operate the movable electrode 218 depending on the relationship between the pressure PE in the vacuum space 214 of the vacuum interrupter 210, the pressure PI in the internal space 12 of the housing 10, and the external pressure PO of the housing 10, i.e., atmospheric pressure.

[0052] The force D acting on the bellows 224 can be obtained by multiplying the effective cross-sectional area A3 of the bellows 224 by the insulating gas pressure PI inside the housing 10. That is, D=PI*A3.

[0053] The force A acting on the drive rod 254 can be obtained by multiplying the effective cross-sectional area A1 of the drive rod 254 by the atmospheric pressure PO, i.e., A=PO*A1.

[0054] The forces B and C acting on the piston 246 are as follows. First, the force B acting due to atmospheric pressure PO can be calculated by multiplying the effective cross-sectional area A2 of the piston 246 by the atmospheric pressure PO: B = PO * A2. Next, the force C acting due to the pressure PI of the insulating gas inside the housing 10 is C = PI * A2. In general, force C is greater than force B.

[0055] 7(a), a force A+D acts on the movable electrode 218 due to the pressure inside and outside the casing 10 and the vacuum of the vacuum interrupter 210. Therefore, in order to separate the movable electrode 218 from the fixed electrode 216, an additional force is required from the actuator 260.

[0056] However, referring to Fig. 7(b), only the force CB acting on the piston 246 is reduced. That is, the final force acting in Fig. 7(b) is (A+D)-(CB). Therefore, the force acting on the movable electrode 218 is relatively reduced compared to the conventional case. As a result, the force required for the actuator 260 to operate the movable electrode 218 can be relatively reduced.

[0057] In addition, if the effective diameter of the bellows 224 and the effective diameter of the piston 246 (or the effective diameter of the airtight packing 248) are made the same or nearly the same, the magnitude of the self-closing force of the vacuum interrupter 210 and the load due to the pressure difference between the inside and outside of the housing during opening and closing operations become similar, and the operating speed of the movable electrode 218 can be made constant during opening, closing, and closing operations.

[0058] Although all components constituting the embodiments of the present invention have been described above as being combined or operating in combination, the present invention is not necessarily limited to these embodiments. That is, all components may be selectively combined and operate in combination, provided that the scope of the present invention is within the scope of the present invention. Furthermore, unless otherwise specified, the terms "comprise," "comprise," "have," and the like used above mean that the component in question may be inherent, and should be interpreted as including other components rather than excluding other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as dictionary-defined terms, should be interpreted in accordance with the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined in the present invention.

[0059] The above description merely exemplifies the technical concept of the present invention, and various modifications and variations may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are for illustrative purposes only and do not limit the technical concept of the present invention. The scope of the technical concept of the present invention should not be limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical concepts within the scope equivalent thereto should be interpreted as being within the scope of the present invention.

Claims

1. A vacuum circuit breaker having a part located inside a housing and another part installed to penetrate the housing, a vacuum interrupter that is installed inside the housing, in which a vacuum space is formed in a vacuum state inside the housing, and that includes a fixed electrode and a movable electrode that moves toward and away from the fixed electrode in the vacuum space; a drive rod that transmits a force for driving the movable electrode and is installed through the housing; and an interlocking mechanism that operates integrally with the drive rod and has a piston with an outer diameter larger than that of the drive rod.

2. 2. The vacuum circuit breaker according to claim 1, wherein the interlocking mechanism further comprises a piston guide installed to penetrate the housing, a guide body of the piston guide including a rod through-hole through which the drive rod passes and which communicates with the outside of the housing, and a cylinder in which the piston is movably installed and which has a piston space open to the inside of the housing.

3. 3. The vacuum circuit breaker according to claim 2, wherein an airtight packing and a piston wear ring are provided between the outer surface of the piston and the inner surface of the piston space.

4. 3. The vacuum circuit breaker according to claim 2, wherein a rod wear ring is provided between the inner surface of the rod through-hole and the outer surface of the drive rod.

5. 2. The vacuum circuit breaker according to claim 1, further comprising a movable rod extending through the housing, one side of which is connected to the movable electrode and the other side of which is connected to the interlocking mechanism, and a bellows sealingly seals the space between the movable rod and the housing.

6. 6. The vacuum circuit breaker according to claim 5, wherein the effective diameter of said bellows and the outer diameter of said piston have the same value.

7. 7. The vacuum circuit breaker according to claim 6, wherein a guide tube is provided through the housing, the movable rod is positioned through the guide tube, and the bellows is provided between the guide tube and the movable rod.

8. The vacuum circuit breaker according to claim 5 , further comprising an insulating rod made of an insulating material for connecting between the movable rod and the piston of the interlocking mechanism.

9. 2. The vacuum circuit breaker according to claim 1, wherein a piston guide on which a piston and a driving rod of the interlocking mechanism are installed is installed through the housing, and a mounting flange is formed around one side of an outer surface of a guide body forming a skeleton of the piston guide, so that one side surface of the mounting flange is in close contact with the outer surface of the housing.

10. 10. The vacuum circuit breaker of claim 9, wherein a rod through-hole through which the driving rod passes is formed through the center of the guide body, and a cylinder having a cylinder space formed therein, one side of which communicates with the rod through-hole and the other side of which communicates with the internal space of the housing, protrudes toward the vacuum interrupting part.

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