Parallel breaking load switch and medium-voltage switchgear equipped with the same

Abstract

To provide a medium and high voltage switchgear that can implement a relatively long braking distance and can flexibly set technical requirements such as over-travel.SOLUTION: A medium and high voltage switchgear having a parallel breaking load switch includes a stationary contact, a moving contact that is configured to be rotatable around a pivot axis among a closed position, a commutation position, and a breaking position, a vacuum interrupter where the stationary contact is electrically connected to a fixed switch contact in the vacuum interrupter, and a cam assembly having a small contact that can rotate around the pivot axis. The parallel breaking load switch in which a moving end of the movable switch contact can be guided by the cam assembly and operatively connected to the cam assembly, and the travel of linear movement is 7 mm or more is provided.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a parallel interrupt load switch, particularly suitable for interrupting power lines of a medium voltage electrical system, including an interrupt load switch with a vacuum circuit breaker. The term "medium voltage" (MT) is used in its ordinary sense, i.e., to indicate a voltage of more than 1000 volts but not more than 52000 volts for AC and more than 1500 volts but not more than 75000 volts for DC. The present disclosure also relates to a medium voltage switch arrangement with a parallel interrupt load switch. [Background technology]

[0002] Circuit breakers and disconnectors for medium or high voltage (high voltage) electric power lines or cables are known to usually include a box in which switch contacts are arranged to move between a mutually contacting position corresponding to the closing of the line and a mutually separated position corresponding to the disconnection of the line. The switch contacts are immersed in a dielectric fluid, which assists in breaking the current by extinguishing any arcs that may remain after the switch contacts separate from each other. Various dielectric fluids have been proposed, such as air, oil, and nitrogen, but sulfur hexafluoride (SF6) is commonly used, as it has good dielectric properties and is suitable for the application. Nevertheless, its use is limited due to its weaknesses, such as the toxicity and corrosiveness of its decomposition products, and its contribution to the greenhouse effect. This calls for the use of vacuum interrupters, which are also used in some disconnectors. The switch contacts are the internal elements of these switch boxes, and vacuum interrupters are most effective in extinguishing the arc current. However, without further improvements, the use of vacuum interrupters in existing circuit breakers cannot be considered from a cost perspective, as they are bulky in terms of material and dimensions.

[0003] To solve the above drawbacks, it is known in particular from CN 102623234 that a vacuum interrupter is arranged in a bypass circuit in parallel with the main circuit of the main switch containing one phase of the electrical equipment. In this structure, during normal operation, i.e. when the main switch is closed, no current passes through the vacuum interrupter, and therefore the current passes through the main circuit. During the operation of disconnecting the main switch, the moving part of the main switch closes the parallel bypass circuit including the vacuum interrupter before the current in the main circuit is interrupted. The current in the main circuit is then interrupted and all the current passes through the vacuum interrupter. Continuing the interrupting stroke, the moving part of the main switch separates the contacts of the vacuum interrupter and the current is interrupted. At the moment the current is interrupted, the current only passes through the vacuum interrupter, so that the occurrence of an arc in the main switch is avoided. Since there is a current passing through the vacuum interrupter only during the transient period of the interrupting current, the vacuum interrupter can be simplified and made smaller than a vacuum interrupter that is usually arranged in series with the main switch.

[0004] However, in a vacuum interrupter, the interruption of the vacuum interrupter is only triggered by the main switch in the interruption stroke. Therefore, the relative arrangement of the vacuum interrupter and the main switch is limited. Furthermore, the kinematic connection of the vacuum interrupter and the main switch needs to be very precise. Considering the number of elements involved in the assembly, the dimensional tolerance of each element in the kinematic connection sequence must be strict.

[0005] Therefore, in the related technical field, there is a technical need to easily and reliably achieve low precision, extend the breaking distance, flexibly set the overtravel, etc., in the formation of moving parts that contribute to the interruption of a vacuum circuit breaker. Summary of the Invention [Problem to be solved by the invention]

[0006] It is therefore an object of the present disclosure to provide a parallel interrupt load switch that overcomes the shortcomings of the prior art. [Means for solving the problem]

[0007] According to one aspect of the disclosure, there is provided a parallel interrupt load switch suitable for interrupting a power line of a medium voltage electric system, the parallel interrupt load switch including: a fixed contact, the fixed contact including a first end connected to the power line and a second end opposite the first end; a moving contact, the moving contact configured to be rotatable about a pivot axis between a closed position, a commutating position, and a breaking position, the moving contact being connected to the second end of the fixed contact and in electrical communication with the fixed contact in the closed position, the moving contact being disconnected from the fixed contact upon rotation about the pivot axis to a breaking position; and a vacuum interrupter including a fixed switch contact and a movable switch contact disposed therein, the fixed contact being electrically connected to the fixed switch contact. The parallel interrupt load switch further includes a cam assembly having a small contact rotatable about a rotation axis, the small contact having a conductor electrically connectable with the moving contact, electrically connected to the vacuum interrupter in response to rotation of the moving contact about the pivot axis, a moving end of the moving switch contact aligned along an axis of the vacuum interrupter and capable of linear movement between an OFF position and an ON position, the moving end of the moving switch contact being guided and operably connected to the cam assembly, the linear movement being 7 mm or more, and in the closed position, the moving contact contacts the fixed contact and is spaced from the small contact, and in the ON position, the moving switch contact contacts the fixed switch contact and current can flow to the moving contact via the fixed contact. Here, the moving contact rotates about the pivot axis in a first rotational direction from a closed position to a commutating position, during the rotation, the moving contact contacts the small contact, and current can flow through the fixed contact and the vacuum interrupter to the moving contact through the small contact, and the moving contact further rotates about the pivot axis in a first rotational direction from the commutating position to a breaking position, and the moving contact drives the small contact to rotate about the rotation axis and actuates the cam assembly, so that the moving end of the moving switch contact moves linearly along the axis of the vacuum interrupter from an on position to an off position, separating the moving switch contact from the fixed switch contact of the vacuum interrupter. According to the parallel breaking load switch of the present disclosure, the technical requirements of low precision, longer breaking distance, and flexible setting ability of overtravel in the moving parts contributing to the interruption of the vacuum circuit breaker can be realized in a simple and reliable manner. Furthermore, the parallel breaking load switch of the present disclosure requires fewer parts and lower costs, and has good reliability.

[0008] In some embodiments, as a preferred aspect, the cam assembly includes a cam frame, wherein a small contact is pivotally connected to the cam frame, and the cam frame is provided with a guide groove for linearly moving a moving end of a movable switch contact between an off position and an on position, and a cam pivotally connected to the cam frame, wherein the cam has an abutment pin operably connected to the small contact and a guide groove for clamping the moving end of the movable switch contact, and the small contact is capable of driving the cam to swing together about the rotation axis, and the moving end of the movable switch contact moves linearly between the off position and the on position via the guide groove and the guide groove.

[0009] In some embodiments, as a preferred aspect, the small contact is designed as an elongated piece, which comprises a first end pivotally attached to the cam frame and a second end opposite the first end, the second end being provided with an elastic seat that can be elastically biased against the moving contact, thus ensuring the continuity of the current and realizing a simple bypass circuit. In some embodiments, as a preferred aspect, the parallel break load switch further includes an insulating bracket that is integrally formed, and includes a horizontal portion for fixedly mounting the cam frame and the vacuum interrupter, and a vertical portion for fixedly mounting the fixed contacts. Therefore, this design ensures the transmission accuracy and effectively reduces the assembly error.

[0010] In some embodiments, as a preferred aspect, the cam assembly further includes a torsion spring fixedly attached to the cam frame, the support legs of the torsion spring operatively biasing the cam to oscillate with the cam relative to the cam frame to store elastic potential energy and thereafter to return the cam to its initial position to release the elastic potential energy.

[0011] In some embodiments, as a preferred aspect, the moving contact includes a pair of spaced apart contact pieces, one end of the contact piece having an outwardly protruding spherical portion and operably connected to the actuator so as to be biased to rotate about a pivot axis between the closed, commutating, and blocking positions, and the other end of the contact piece having an outwardly protruding abutment portion that forms a surface contact with the second end of the fixed contact.

[0012] In some embodiments, as a preferred aspect, the parallel interrupt load switch further includes a voltage equalization ring disposed adjacent the spherical portion of the contact piece and used to equalize the electric field of the current through the moving contact, and a semicircular shielding cover disposed adjacent but in spaced relation to the energized portion of the contact piece and used to prevent partial discharge.

[0013] In some embodiments, as a preferred aspect, the minor contact is made of an insulating material and the second end includes a layer of insulating material on one side opposite the contact piece.

[0014] In some embodiments, as a preferred aspect, the parallel interrupt load switch further includes a ground contact located on one side of the moving contact and electrically connectable to a ground conductor, the ground contact being generally U-shaped in design and including a first end connected to the ground conductor, a second end opposite the first end, and a hollow portion located between the first end and the second end, the second end having a pair of contact legs that coincide with the moving contact.

[0015] According to another aspect of the present disclosure, there is further provided a medium voltage switch including a shell filled with an insulating gas and a parallel interrupt load switch disposed within the shell.

[0016] Other features and advantages of the present disclosure will in part be apparent to those skilled in the art upon reading this specification, and in part will be described in the following detailed embodiments in conjunction with the accompanying drawings.

[0017] The embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a front view of a medium-voltage switch equipped with a parallel interrupt load switch according to the present disclosure. [Diagram 2] FIG. 2 is a side view of a medium-voltage switch device including a parallel interrupt load switch according to the present disclosure. [Diagram 3] FIG. 3 is a front view of a medium-voltage switch device including a parallel interrupt load switch according to the present disclosure. [Figure 4] FIG. 4 is a top view of a medium-voltage switch device having a parallel interrupt load switch according to the present disclosure. [Diagram 5] 5-6 are perspective and side views showing the main circuit of a parallel break load switch according to the present disclosure with the moving contacts removed. [Figure 6] 5-6 are perspective and side views showing the main circuit of a parallel break load switch according to the present disclosure with the moving contacts removed. [Figure 7] FIG. 7 is a side view of a moving contact of a parallel interrupt load switch according to the present disclosure. [Figure 8] FIG. 8 is a perspective view of a parallel interrupt load switch according to the present disclosure with some components of the medium voltage switch removed to better show details. [Figure 9] FIG. 9 is a side view of a parallel interrupt load switch according to the present disclosure with some components of the medium voltage switch removed to better show details. [Figure 10] 10-12 are diagrams illustrating different views of a parallel interrupt load switch according to the present disclosure, with some components of the high voltage switch removed to better show details. [Figure 11] 10-12 are diagrams illustrating different views of a parallel interrupt load switch according to the present disclosure, with some components of the high voltage switch removed to better show details. [Figure 12] 10-12 are diagrams illustrating different views of a parallel interrupt load switch according to the present disclosure, with some components of the high voltage switch removed to better show details. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The schematic solution of the parallel interruption load switch and the high voltage switch device including the same disclosed by the present disclosure will be described in detail with reference to the attached drawings. The attached drawings provided are used to illustrate some embodiments of the present disclosure, but the attached drawings do not need to be drawn according to the dimensions of a specific embodiment, and some features may be locally enlarged, deleted, or divided in order to better illustrate and explain the contents of the present disclosure. In addition, the positions of some components in the attached drawings may be adjusted according to actual needs without affecting the technical effect. The phrase "in the attached drawings" or similar phrases appearing in this specification do not necessarily refer to all of the attached drawings or examples.

[0020] In the following, some directional terms for describing the accompanying drawings, such as "inside", "outside", "upper", "lower", etc., may be understood to have their ordinary meaning and refer to those directions relative to the ordinary line of sight of the accompanying drawings. Unless otherwise stated, directional terms in this specification essentially refer to conventional directions understood by those skilled in the art.

[0021] As used in this disclosure, the terms "first," "first one," "second," "second one," and similar terms do not denote any order, quantity, or importance, but rather are used to distinguish one component from another component in this disclosure.

[0022] In order to make the objectives, structure, features and functions of the present disclosure more comprehensible, details are described below in combination with embodiments.

[0023] As shown in Figures 1-4 of the present disclosure, the medium voltage switch according to the present disclosure is particularly suitable for connection in a medium voltage circuit as a load interrupt switch. Thus, the medium voltage switch is used to provide interruption and circuit breaking functions under predetermined circuit conditions (nominal or overload conditions), and is particularly used to ground the load side portion of the circuit.

[0024] As shown in FIG. 1, in one embodiment of the present invention, the high voltage switch belongs to a multi-phase (e.g., three-phase) type and includes a plurality of (e.g., three) electrodes. Furthermore, the high voltage switch includes a shell C, preferably made of an insulating material, which advantageously defines an interior space capable of accommodating the electrodes. As shown in FIG. 1, the insulating shell C has an elongated shape (e.g., generally cubic shape) extending along a main longitudinal axis. The multiple electrodes are arranged side by side along corresponding horizontal planes perpendicular to the main longitudinal axis of the medium voltage switch. The interior space of the medium voltage switch is filled with pressurized dry air or another insulating gas with low environmental impact (such as a mixture of oxygen, nitrogen, carbon dioxide and / or fluorine-based gases).

[0025] As shown in Fig. 1, each electrode is electrically connected to a power line of a medium voltage electric system and correspondingly interrupted by the parallel interrupt load switch of the present disclosure, the parallel interrupt load switch 100 includes a fixed contact 1 including a first end 11 connected to the power line and a second end 12 opposite to the first end, the first end 11 protruding from the upper side of an insulating shell C and comprising a connector connected with an external power line, and the second end 12 is a flake disposed inside the insulating shell C and protruding inward. Those skilled in the art can also know that the fixed contact 1 can be realized according to other solutions of known types (for example, configured according to multiple blades including multiple fixed contact pieces), which will not be described in detail here for the sake of brevity.

[0026] The parallel interrupt load switch 100 further includes a moving contact 2 that is at least partially made of a conductive material and can be electrically connected to a power line of an electrical system via a wiring terminal 25 disposed at a lower end. As shown in Figs. 1 and 3, the moving contact 2 can pivot back and forth about a corresponding pivot axis A2 that is generally parallel to a main longitudinal axis of the medium voltage switch device. Specifically, the moving contact 2 can rotate in a first rotational direction away from the second end 12 of the fixed contact 1 and toward the ground contact 3, or in a second rotational direction, which is opposite to the first rotational direction and away from the ground contact 3 and toward the second end 12 of the fixed contact 1. As will be better explained below, the moving contact 2 moves in a first rotational direction during interrupting and commutating operations of the high voltage switch device, and moves in a second rotational direction during closing or reconnecting operations of the switch device. In this way, the movable contact 2 can move back and forth around the pivot axis A2, so that the movable contact 2 can be electrically connected to the second end 12 of the fixed contact 1, separated from the second end 12 of the fixed contact 1, electrically connected to the ground contact 3, or separated from the ground contact 3.

[0027] In a preferred embodiment, the moving contact 2 can be formed by a pair of spaced apart contact pieces made of a conductive material. Each contact piece has an end hinged to a corresponding wiring terminal 25 at the pivot axis A2 and forms an opposite free end electrically coupled to the second end 12 of the fixed contact 1. Furthermore, to realize the rotation of the moving contact 2 about the pivot axis A2, the high voltage switch device includes an actuator 21, which provides a suitable actuation force to actuate the moving contact 2 (FIG. 1). The actuator 21 here can be, for example, a mechanical actuator, an electric motor or a solenoid actuator.

[0028] In a preferred embodiment, as shown in FIG. 11, one end of the contact piece of the moving contact 2 has a spherical portion that protrudes outward and is operatively connected to the actuator 21, and is biased to rotate around the pivot axis A2 between the closed position, the commutating position, and the breaking position, which will be described in detail later, and the other end of the contact piece of the moving contact 2 has an abutting portion 22 that protrudes outward and can make surface contact with the second end 12 of the fixed contact 1. The added abutting portion 22 can obviously increase the contact area between the moving contact 2 and the fixed contact 1, thereby improving the current passing capacity, so that ablation and fusion are less likely to occur when the moving contact 2 performs the breaking operation. At the same time, the lower part of the moving contact 2 is designed to be spherical, which can reduce the friction and resistance of the oscillating motion and meet the requirements of the temperature rise test. More preferably, as shown in Figures 10 to 11, the moving contact 2 also includes a pressure equalizing ring 24 disposed adjacent to the spherical portion of the contact piece and used to equalize the electric field of the current flowing through the moving contact, and a semicircular shielding cover 23 disposed adjacent to the abutting portion of the contact piece at a distance and used to prevent partial discharge, which help to prevent partial discharge during normal operation of the medium-voltage electrical equipment and equalize the electric field inside the electrical equipment, and are beneficial to improving the operational reliability and life of the medium-voltage electrical equipment.

[0029] In addition, the medium voltage electrical equipment may also include a ground contact 3 located on one side of the moving contact 2 and electrically connectable to a ground conductor, the ground contact 3 being designed in a generally U-shape and including a first end connected to the ground conductor, a second end opposite to the first end, and a hollow portion located between the first end and the second end, and the second end being provided with a pair of contact legs 31 (see Figs. 8-10) that coincide with the moving contact. In the present disclosure, since the ground contact 3 is designed in a U-shape, those skilled in the art can know that according to the right-hand rule, the two sides of the electrodynamic force are opposite in direction, and most of the electrodynamic force acting on the moving contact 3 can be counteracted, making the ground close test more stable and more reliable.

[0030] 5-6 show the details of the following parallel interrupt load switch 100 according to the present disclosure. Specifically, the parallel interrupt load switch 100 also includes a vacuum circuit breaker 4 having a fixed switch contact and a movable switch contact, and the fixed contact 1 is electrically connected to the fixed switch contact. The vacuum circuit breaker 4 as an example here includes a pair of fixed switch contacts and a movable switch contact, and the fixed switch contact can be electrically connected to the first end 11 of the fixed contact 1, and the vacuum circuit breaker 4 is fixedly connected to the fixed contact 1. At the same time, the movable switch contact is driven by a movable end 42 extending from the shell of the vacuum circuit breaker 4. In this structure, during normal operation, that is, when the moving contact 2 and the fixed contact 1 are closed to allow current to flow in the main circuit, no current flows in the vacuum circuit breaker 4. During the operation of separating the moving contact 2 and the fixed contact 1, before the current in the main circuit is interrupted, the movable part of the moving contact 2 switches to a parallel bypass circuit including the vacuum circuit breaker. After that, the current in the main circuit is interrupted, and all the current passes through the vacuum circuit breaker. As the interruption operation continues, the moving part of the main circuit separates the contacts of the vacuum interrupter, and the current is interrupted. Therefore, at the moment of interrupting the current, the current only passes through the vacuum interrupter, so that the generation of an arc in the main circuit is avoided. The structure of the vacuum interrupter 4 is known, and for example, the vacuum interrupter may be a VI-8 vacuum interrupter available from Eaton, and its structure will not be described in detail here for the sake of brevity.

[0031] Since the medium voltage electrical equipment according to the present disclosure does not use sulfur hexafluoride (SF6) gas as the insulating medium, but other gases with poorer insulating properties, higher requirements are imposed on the breaking distance of the arc interrupter and the kinematic connections between the components of the load switch, which will be further explained below in conjunction with the accompanying drawings.

[0032] As shown in Fig. 5-6, the parallel break load switch 100 includes a cam assembly, the cam assembly includes a small contact 7 rotatable around a rotation axis A1, and the small contact 7 includes a conductor 6 electrically connectable with the moving contact 2 so as to be electrically connected with the vacuum circuit breaker 4 in response to the rotation of the moving contact 2 around a pivot axis A2. Preferably, the cam assembly includes a cam frame 5, the small contact 7 is pivotally connected to the cam frame 5 via a pivot point 52 of a pivot pin, for example, and the cam frame 5 includes a guide groove 51 for guiding the moving end 42 of the moving switch contact to move linearly between an OFF position and an ON position. The cam assembly also includes a cam 8 pivotally connectable to the cam frame 5, the cam 8 being generally designed in a half-moon shape and pivotally attached to the pivot point 52 by a pivot pin, and the cam 8 includes an abutment pin 82 operably connected with the small contact 7 and a guide groove 81 for sandwiching the moving end 42 of the moving switch contact. Therefore, when the small contact 7 drives the cam 8 to swing together about the rotation axis A1, the moving end 42 of the movable switch contact can move linearly between the OFF position and the ON position via the lead-out groove 81 and the guide groove 51, the moving end 42 of the movable switch contact coincides with the axis of the vacuum circuit breaker 4, and the stroke of the linear movement is 7 mm or more.

[0033] Those skilled in the art can know that the above-mentioned cam assembly realizes the interruption of the vacuum circuit breaker 4 by rotating the small contact 7 which can be used as a lever, that is, the combination of the rotation pair realized by the moving contact 2, the lever realized by the small contact 7, and the motion of the guide groove 81 and the leading groove 51. The contact angle of the moving contact 2 and the interruption stroke of the vacuum circuit breaker 4 can be controlled to 7mm or less, and the overtravel can also be set by the length of the guide groove 81 of the cam 8 and the leading groove 51 of the cam frame 5 and their interaction and the length of the force arm of the small contact 7. In a preferred embodiment, in order to ensure that the vacuum circuit breaker 4 is electrically switched on at the initial position, the cam assembly further includes a torsion spring 9 fixedly attached to the cam frame 5, and the support leg of the torsion spring 9 operatively biases the cam 8 to pivot with the cam 8 relative to the cam frame 5 to store elastic potential energy, and then release the elastic potential energy to return the cam 8 to the initial position. Thus, as the cam 8 rotates clockwise or counterclockwise, the action of the torsion spring 9 allows the cam to be quickly reset.

[0034] In a preferred embodiment, as shown in Fig. 7 and Fig. 9, the small contact 7 is designed as an elongated piece, which includes a first end pivotally mounted on the cam frame 5 and a second end opposite to the first end, and the second end is provided with an elastic sheet 71 that elastically biases the moving contact 2. The elastic sheet 71 is designed to expand outward here and is located on the top of the second end of the small contact 7, and when the moving contact 2 performs an interrupting operation around the pivot axis A2, the elastic sheet 71 can snap into the inside of the two contact pieces of the moving contact 2. This design ensures the continuity of the current. In addition, a copper sheet 73 that is electrically connected to the conductor 6 is arranged below the elastic sheet 71, and when the operation continues, the moving contact 2 may come into contact with the copper sheet 73, and the current is transmitted to the vacuum interrupter 4 through the copper sheet 73 and the conductor 6, and the above design can realize a simple bypass circuit. To prevent switching on of the bypass circuit when the moving contact 2 swings to the closed position in the opposite direction, the minor contact 7 is preferably made of an insulating material and the second end of the minor contact is provided with a layer of insulating material on its face opposite the elastic sheet 71.

[0035] In order to fixedly mount the cam assembly on the medium voltage switch, as shown in Figs. 5-6, the parallel break load switch 100 also includes an integrally constructed insulating bracket 10, which includes a horizontal portion 10B for fixedly mounting the cam frame 5 and the vacuum circuit breaker 4, and a vertical portion 10A for fixedly mounting the fixed contact 1, and the insulating bracket 10 is injection molded by high strength PC material, and the three phases are mounted on the same plane. After the vacuum circuit breaker 4 and the fixed contact 1 are mounted, the cam assembly and the fixed contact 1 can be mounted on the same insulating bracket 10, so that the transmission accuracy can be ensured and the assembly error can be effectively reduced. In addition, the horizontal portion 10B of the insulating bracket 10 can also be fixedly provided with a lead holder 53, and as best shown in Fig. 6, the lead holder 53 includes a horizontal mounting portion that is mounted on a plane below the horizontal portion 10B and a circular arc portion for leading out the conductor 6, so that the cross section has a mirror "5" shape. As best shown in FIG. 10, in the installed state, a groove for embedding the conductor 6 is arranged in the arc portion, and the conductor moves along an arc path defined by the groove in the arc portion, thereby effectively preventing the conductor 6 from being broken due to repeated bending, which would affect the reliability and lifespan of the entire parallel interrupting load switch 100.

[0036] According to the present disclosure, the parallel interrupt load switch 100 can perform different kinds of operations, each of which corresponds to a predetermined change in operating state. Specifically, as shown in FIG. 8, the moving contact 2 is in a closed position, and then the vacuum interrupter 4 is in a default closed position, that is, the fixed switch contact and the movable switch contact are closed. When the moving contact 2 is in a closed position, the moving contact 2 is kept in close contact with the second end 12 of the fixed contact 1 by the abutment 22, and the current can flow from the first end of the fixed contact 1 to the fixed contact and further through the moving contact 2 to the wiring terminal 25, and the parallel interrupt load switch 100 can be considered to be in a closed configuration.

[0037] Then, when the actuator 21 is actuated, the moving contact 2 starts to rotate about the pivot axis A2 and at a certain rotation point comes into contact with the second end of the fixed contact 1 and the cam assembly (specifically, the small contact 7 of the cam assembly) connected to the vacuum circuit breaker 4, thereby forming a commutation point and, since the fixed switch contact and the movable switch contact of the vacuum circuit breaker 4 are closed, a bypass current circuit is formed from the first end 11 of the fixed contact 1 directly to the moving contact 2 via the vacuum circuit breaker 4 and the conductor 6. At this time, the parallel interrupt load switch 100 is considered to be in a commutation configuration.

[0038] Then, the moving contact 2 continues to rotate around the pivot axis A2 under the action of the actuator 21, so that it is separated from the second end 12 of the fixed contact 1 but remains in electrical contact with the small contact 7; furthermore, the fixed switch contact and the moving switch contact of the vacuum circuit breaker 4 are still in contact with each other, so that the current flows only from the first end 11 of the fixed contact 1 to the vacuum circuit breaker 4, and then through the vacuum circuit breaker 4 to the moving contact 2. Then, the moving contact 2 continues to rotate, and during the rotation of the moving contact, the small contact 7 continues to rotate correspondingly, and the cam 8 is driven by the abutment pin 82 to rotate together with the cam frame 5, with the pivot point 52 as the rotation axis A1, so that the moving end 42 of the moving switch contact accommodated in the leading groove 51 and the guide groove 81 of the cam assembly moves linearly from the ON position to the OFF position along the axis of the vacuum circuit breaker 4, and the moving switch contact is separated from the fixed switch contact of the vacuum circuit breaker 4, and the stroke of the linear movement is 7 mm or more. As a result, the contacts of the vacuum interrupter 4 are already broken to interrupt the current. Finally, the moving contact 2 continues to rotate and passes the small contact 7, which is reset by the action of the torsion spring 9, driving the vacuum interrupter 4 back to the default closed configuration, but since the moving contact 2 is already separated from the small contact 7 and the first end 12 of the fixed contact 1, the parallel interrupt load switch 100 is already in the breaking configuration, and when the moving contact rotates and touches the ground contact 3 and is stopped by the ground contact, the parallel interrupt load switch 100 is in the grounding configuration.

[0039] Those skilled in the art will appreciate that by actuating the moving contact 2 to rotate in the opposite direction about the pivot axis A2 via the actuator 21, the parallel break load switch 100 can be changed from the grounded configuration to the closed configuration, and a current path is formed between the second end 11 of the fixed contact 1 and the moving contact 2, and the vacuum interrupter 4 is configured with the contacts closed, and no current flows through the vacuum interrupter. The parallel break load switch 100 is then prepared for another break operation. Note that since the opposite side of the small contact 7 is insulated, the bypass circuit will not be turned on even if the moving contact 2 swings in the opposite direction to the closed position.

[0040] Although this specification is described according to various embodiments, it should be understood that each embodiment does not include only one independent technical solution. The description in this specification is merely for clarity. Those skilled in the art should take this specification as a whole, and can appropriately combine the technical solutions in each embodiment to form other embodiments that can be understood by those skilled in the art.

[0041] The above are merely exemplary embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure. Equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principle of the present disclosure shall belong to the protection scope of the present disclosure. [Explanation of symbols]

[0042] 100: Parallel interrupt load switch, C:Shell, 1: fixed contact, 11: first end, 12: second end, 10: insulating bracket, 10A: vertical part, 10B: horizontal part, 2: moving contact, 21: actuator, 22: contact point, 23: shielding part, 24: equalizing ring, 25: wiring terminal, 3: Ground contact, 31: Contact leg, 4: vacuum circuit breaker, 41: fixed end, 42: moving end, 5: cam frame, 51: lead groove, 52: pivot point, 53: lead holder, 6: conductor, 7: small contact, 71: elastic sheet, 72: lower end, 73: copper plate, 8: cam, 81: guide groove, 82: abutment pin, 9: Torsion spring, A1: Rotation axis, A2: Pivot axis

Claims

1. 1. A parallel interrupt load switch suitable for interrupting power lines of a medium voltage electrical system, comprising: a fixed contact including a first end connected to the power line and a second end opposite the first end; a moving contact configured to be rotatable about a pivot axis between a closed position, a commutating position, and a breaking position, the moving contact being connected to the second end of the fixed contact and in electrical communication with the fixed contact in the closed position, and the moving contact being disconnected from the fixed contact upon rotation about the pivot axis to the breaking position; a vacuum interrupter having a fixed switch contact and a movable switch contact disposed therein, the fixed contact being electrically connected to the fixed switch contact; a cam assembly including a small contact rotatable about a rotation axis, the small contact including a conductor electrically connectable with the moving contact, electrically connected to the vacuum interrupter in response to rotation of the moving contact about a pivot axis, a moving end of the moving switch contact aligned along an axis of the vacuum interrupter and capable of linear movement between an OFF position and an ON position, the moving end of the moving switch contact being guided and operably connected to the cam assembly, the amount of linear movement being 7 mm or more, in a closed position the moving contact contacts the fixed contact and is spaced from the small contact, and in an ON position the moving switch contact contacts the fixed switch contact, and current can flow to the moving contact via the fixed contact, the moving contact rotates about the pivot axis in a first rotational direction from a closed position to a commutating position, during which the moving contact contacts the minor contact and current can flow through the minor contact to the moving contact, through the fixed contact and through the vacuum interrupter; and The moving contact further rotates about the pivot axis in a first rotational direction from the commutating position to the interrupting position, and the moving contact drives the small contact to rotate about the rotation axis to actuate the cam assembly so that the moving end of the movable switch contact moves linearly along the axis of the vacuum interrupter from the on position to the off position, separating the movable switch contact from the fixed switch contact of the vacuum interrupter, in a parallel interrupting load switch.

2. The cam assembly includes: a cam frame, the small contact being pivotally connected to the cam frame, the cam frame being provided with a guide groove for linearly moving a moving end of the movable switch contact between an OFF position and an ON position; a cam pivotally connected to the cam frame, the cam including an abutment pin operably connected to the small contact and a guide groove for receiving a moving end of the movable switch contact; 2. The parallel break load switch according to claim 1, wherein the small contact is capable of driving the cam to oscillate together with the small contact about the rotation axis, and a moving end of the movable switch contact moves linearly between the off position and the on position via the lead-out groove and the guide groove.

3. 3. The parallel breaking load switch according to claim 2, characterized in that the small contact is designed as an elongated piece having a first end pivotally mounted on the cam frame and a second end opposite the first end, the second end being provided with an elastic sheet that can elastically abut against the moving contact.

4. 3. The parallel interrupt load switch according to claim 2, further comprising an insulating bracket integrally formed with the cam frame and the vacuum interrupter, the insulating bracket having a horizontal portion for fixedly mounting the cam frame and the vacuum interrupter, and a vertical portion for fixedly mounting the fixed contacts.

5. 3. The parallel interrupt load switch of claim 2, wherein the cam assembly further includes a torsion spring fixedly mounted to the cam frame, the support leg of the torsion spring operatively biasing the cam to oscillate with the cam relative to the cam frame to store elastic potential energy and thereafter to return the cam to an initial position to release the elastic potential energy.

6. 2. The parallel break load switch of claim 1, wherein the movable contact includes a pair of spaced apart contact pieces, one end of the contact piece having an outwardly protruding spherical portion and operatively connected to an actuator so as to be urged to rotate about the pivot axis between the closed position, the commutating position, and the breaking position, and the other end of the contact piece having an outwardly protruding abutment portion formed to make surface contact with a second end of the fixed contact.

7. 7. The parallel interrupt load switch of claim 6, further comprising a voltage equalization ring disposed adjacent the spherical portion of the contact piece and used to equalize the electric field of the current through the moving contact, and a semicircular shielding cover disposed adjacent but in spaced relation to the generally spherical portion of the contact piece and used to prevent partial discharge.

8. 4. The parallel interrupt load switch of claim 3, wherein the minor contact is made of an insulating material and the second end includes a layer of insulating material on a side opposite the contact piece.

9. 2. The parallel interrupt load switch of claim 1, further comprising a ground contact located on one side of the moving contact and electrically connectable to a ground conductor, the ground contact being designed generally U-shaped and including a first end connected to the ground conductor, a second end opposite the first end, and a hollow portion located between the first end and the second end, the second end being provided with a pair of contact legs aligned with the moving contact.

10. 2. The parallel breaking load switch of claim 1, further comprising a lead holder connected to a lower portion of the horizontal portion of the insulating bracket, the lead holder having an arc portion for guiding a conductor, the arc portion having a groove for embedding the conductor.

11. A medium-high voltage switch device comprising: a shell filled with an insulating gas; and a parallel interrupting load switch disposed in the shell, the parallel interrupting load switch being the parallel interrupting load switch according to any one of claims 1 to 10.

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