A magnetic blowout chamber and breaking device

Abstract

The utility model discloses a kind of magnetic blow-out arc chamber and breaking device, belong to power equipment breaking technical field, magnetic blow-out arc chamber includes insulating shell;Two conducting rods, respectively wear in insulating shell top and bottom;Static contact and moving contact, respectively with two conducting rods far from the end of insulating shell connection;Bellows, slidingly set on moving contact, and with insulating shell connection;Multiple arc-extinguishing grid, with the two sides of insulating shell inner wall connection and form parallel array;First arc-striking piece, with the two sides of static contact connection;Second arc-striking piece, set in insulating shell bottom and located the two sides of moving contact motion track;Magnetic blow component, set in insulating shell outside.In the utility model, through the synergistic effect of arc-striking piece and arc-extinguishing grid piece, arc moves along arc-striking piece surface and enters arc-extinguishing grid area in the process of moving contact and static contact breaking, arc is cut into multiple sections to realize the significant promotion of arc voltage, the rapid establishment of high arc voltage can effectively suppress fault current, to accelerate arc extinguishing.

Description

Technical Field

[0001] This utility model relates to a magnetic blowout arc extinguishing chamber and a switching device, belonging to the field of power equipment switching technology. Background Technology

[0002] With the rapid development of high-voltage direct current (HVDC) transmission technology, the reliable breaking capacity of DC circuit breakers has become a key challenge. Unlike alternating current (AC), direct current (DC) does not have a natural zero-crossing point; a zero-crossing point must be artificially created to achieve DC current breaking. In existing DC circuit breaker topologies, the main current-carrying branch (usually composed of a small number of switch breaks connected in series) needs to reliably transfer the fault current to the parallel transfer branch during breaking, creating a zero-crossing condition for the current in the main current-carrying branch, thereby achieving reliable breaking. The transfer branch typically utilizes an oscillating circuit composed of inductors and capacitors to generate a resonant current, which gradually increases and eventually forces the current in the main current-carrying branch to cross zero. The core driving force of this transfer process depends on the arc voltage generated when the main current-carrying branch switch is opened. Only when the arc voltage generated by the switch break is high enough can it effectively excite the oscillating circuit of the transfer branch to resonate, thereby achieving reliable switching of the current path. Existing switch break technology is limited by the arc-extinguishing chamber structure, making it difficult to fully elongate, divide, and cool the arc, resulting in a limited peak arc voltage that can ultimately be established. During the circuit breaker tripping process, the arc may deviate from the expected path or be blocked by the arc-extinguishing grid, thus delaying the effective establishment of the arc voltage. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a magnetic blowout arc extinguishing chamber and a breaking device. By relying on the arc extinguishing grid to divide the electric arc into multiple short arc units connected in series, the arc voltage is significantly improved by increasing the arc voltage drop, thereby accelerating the effective establishment process of the arc voltage.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0005] In a first aspect, this utility model discloses a magnetic blowout arc extinguishing chamber, comprising:

[0006] Insulating outer casing;

[0007] Two conductive rods are respectively inserted through the top and bottom of the insulating shell;

[0008] The stationary contact and the moving contact are respectively connected to the ends of the two conductive rods away from the insulating shell;

[0009] A bellows is slidably fitted onto the moving contact and connected to the insulating shell;

[0010] Multiple arc-extinguishing grids are connected to both sides of the inner wall of the insulating shell and form a parallel array;

[0011] The first arc-inducing plate is connected to both sides of the stationary contact;

[0012] The second arc-starting piece is disposed at the bottom of the insulating shell and located on both sides of the moving contact's movement trajectory;

[0013] The magnetic blow-out component is located outside the insulating housing.

[0014] The arc-extinguishing grid sheet has the shape of a flat plate, a folded plate, and a curved plate. The end of the arc-extinguishing grid sheet away from the insulating shell is generally straight, arc-shaped, or umbrella-shaped.

[0015] The insulating outer shell is made of epoxy resin or ceramic, and the interior is either a vacuum or filled with gas, including one or any combination of air, SF6, hydrogen and nitrogen.

[0016] The first and second arc-starting plates are made of nickel-iron alloy, copper-tungsten alloy, or copper-chromium alloy; the arc-extinguishing grid is made of POM, PMMA, nylon, ceramic, copper, or iron.

[0017] The first and second arc-inducing plates have structural forms including straight panel and curved panel.

[0018] The length of the arc-extinguishing grid is set to a fixed equal length, or arranged in a stepped decreasing manner along the contact breaking direction.

[0019] The magnetic blowout component includes:

[0020] Pre-charged capacitor;

[0021] The discharge thyristor is connected at one end to the positive terminal of the pre-charged capacitor.

[0022] An arc-blowing coil is connected at one end to the other end of the discharge thyristor and at the other end to the negative terminal of the pre-charged capacitor.

[0023] A freewheeling diode is connected in parallel across the two ends of the arc-blowing coil.

[0024] The inner wall of the insulating shell is provided with a slot, and the end of the arc-extinguishing grid plate extends into the slot.

[0025] Secondly, this utility model discloses a switching device, comprising a main current-carrying branch, a transfer branch, and an overvoltage limiting branch connected in parallel;

[0026] The main current-carrying branch consists of one or more magnetic blowout arc-extinguishing chambers forming a series of fast mechanical switches;

[0027] The transfer branch is composed of one or more high-capacity power electronic modules connected in series.

[0028] The overvoltage limiting branch includes a metal oxide surge arrester.

[0029] Thirdly, this utility model discloses a switching device, including a main current-carrying branch, a transfer branch, and an overvoltage limiting branch connected in parallel;

[0030] The main current-carrying branch is composed of one or more magnetic blowout arc-extinguishing chambers forming a series of fast mechanical switches;

[0031] The transfer branch is composed of an oscillating capacitor and an inductor connected in series;

[0032] The overvoltage limiting branch includes a metal oxide surge arrester.

[0033] The beneficial effects of this utility model are as follows: This utility model provides a magnetic blowout arc extinguishing chamber and a breaking device. Multiple arc extinguishing grid plates are connected to both sides of the inner wall of the insulating shell and form a parallel array. The first arc-inducing plate is connected to both sides of the stationary contact. The second arc-inducing plate is set at the bottom of the insulating shell and located on both sides of the moving contact's trajectory. The magnetic blowout component is set outside the insulating shell. Through the coordinated magnetic field control of the two-stage arc-inducing plates and the optimization of the arc extinguishing grid plate group structure and spatial layout, the arc is divided into multiple short arc units connected in series by the arc extinguishing grid plates. By increasing the arc voltage drop, the arc voltage is significantly improved, the effective arc voltage establishment process is accelerated, the arc directional movement speed and the arc cutting efficiency of the arc extinguishing grid plates are significantly improved, the arc extinguishing is accelerated, the arc voltage at the time of breaking is significantly improved, and an effective artificial zero-crossing point is constructed. This can achieve a short-circuit current breaking capacity with high reliability and high breaking capacity. Attached Figure Description

[0034] Figure 1 This is the circuit topology diagram of the magnetic blow-out component of this utility model;

[0035] Figures 2 to 5 The diagram shows the shape and structure of several other arc-extinguishing grid plates in this utility model;

[0036] Figures 6 to 10 Here are the shape and structure diagrams of several other arc-inducing plates in this utility model;

[0037] Figure 11 and Figure 12 This is the circuit topology and breaking principle diagram of the breaking device in this utility model during operation;

[0038] The figures are labeled as follows: 1-Insulating shell; 2-Stationary contact; 3-Belled tube; 4-First arc-inducing plate; 5-Arc-extinguishing grid plate; 6-Second arc-inducing plate; 7-Moving contact; 8-Conductive rod; 9-Magnetic blow-out component; 91-Pre-charge capacitor; 92-Discharge thyristor; 93-Arc-blowing coil; 94-Freewheeling diode. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the protection scope of the present invention.

[0040] Example 1

[0041] like Figures 2 to 10 As shown, this utility model discloses a magnetic blowout arc-extinguishing chamber, including an insulating shell 1, a stationary contact 2, a bellows 3, a first arc-inducing plate 4, an arc-extinguishing grid plate 5, a second arc-inducing plate 6, and a moving contact 7. Two conductive rods 8 are respectively inserted through the top and bottom of the insulating shell 1. The stationary contact 2 and the moving contact 7 are respectively connected to the ends of the two conductive rods 8 away from the insulating shell 1. The bellows 3 is slidably sleeved on the moving contact 7 and connected to the insulating shell 1, isolating the gas inside the arc-extinguishing chamber from the gas outside the insulating shell. Multiple arc-extinguishing grid plates 5 are connected to both sides of the inner wall of the insulating shell 1 and form a parallel array. In some embodiments, slots are provided on the inner wall of the insulating shell 1, and the ends of the arc-extinguishing grid plates 5 extend into the slots. The first arc-inducing plate 4 is connected to both sides of the stationary contact 2, and the second arc-inducing plate 6 is disposed at the bottom of the insulating shell 1 and located on both sides of the movement trajectory of the moving contact 7. The first arc-inducing plate 4 and the second arc-inducing plate 6 cooperate with each other in space. During the circuit breaking process, the electric arc is controlled by the external magnetic field to enter the multiple arc-extinguishing grid plates 5 along the surfaces of the first arc-inducing plate 4 and the second arc-inducing plate 6, and is cut into multiple arc segments to improve the arc voltage.

[0042] In addition, the magnetic blowout arc-extinguishing chamber of this invention also includes a magnetic blowout component 8, which is disposed outside the insulating shell 1 and is used to generate a magnetic field in the separation area between the moving contact 7 and the stationary contact 2. The direction of the magnetic field generated by the magnetic blowout component 8 interacts with the direction of arc movement guided by the first arc-initiating plate 4 and the second arc-initiating plate 6, driving the arc to accelerate into the area of ​​the arc-extinguishing grid plate 5.

[0043] Figure 1 The circuit topology of the external magnetic blowout component 9 in this invention is shown. The circuit topology constitutes a controllable discharge circuit, mainly including a pre-charge capacitor 91, a discharge thyristor 92, an arc-blowing coil 93, and a freewheeling diode 94. One end of the discharge thyristor 92 is connected to the positive terminal of the pre-charge capacitor 91, and one end of the arc-blowing coil 93 is connected to the other end of the discharge thyristor 92, while the other end is connected to the negative terminal of the pre-charge capacitor 91. The freewheeling diode 94 is connected in parallel across the arc-blowing coil 93, providing a freewheeling path for the induced electromotive force generated when the current of the arc-blowing coil 93 is turned off. The discharge thyristor 92 can also be replaced by power electronic devices such as IGBTs, IGCTs, and IEGTs. When the discharge thyristor 92 is controlled to conduct, it releases the energy stored in the energy storage capacitor to the arc-blowing coil 93, exciting the generation of an arc-blowing magnetic field.

[0044] In this utility model, the arc-extinguishing grid plate 5 is a flat plate, a folded plate, or a curved plate. One end of the arc-extinguishing grid plate 5 is inserted into the inner wall of the insulating shell 1 for fixation, and the other end is in the shape of a straight line, an arc, or an umbrella, or other shapes. Figure 2 and Figure 3 A rectangular flat arc-extinguishing grid plate 5 is provided. One end of each arc-extinguishing grid plate is fixed at equal intervals to the inner wall of the insulating shell 1, and the other end extends to form a straight free end parallel to the arc-extinguishing motion direction, thereby forming parallel arc-splitting channels in the arc-extinguishing chamber. The length of the arc-extinguishing grid plate 5 is set as follows: Figure 2 As shown, fixed equal length, or as Figure 3 The arrangement shown is in a stepped decrease along the contact breaking direction.

[0045] Figures 4 to 5 Arc-extinguishing grids with either bent or curved plate configurations are provided. One end of each arc-extinguishing grid 5 is fixed at equal intervals within the inner wall of the insulating shell 1, while the other end extends radially inward toward the central axis of the arc-extinguishing chamber, forming a radial umbrella-shaped array. The inwardly extending end of the arc-extinguishing grid 5 is further constructed as an arc-shaped curved surface. Driven by the Lorentz force generated by the external magnetic field of the breaking device, the arc is forcibly attracted to the convex surface of the arc-shaped curved surface and moves along the tangent direction of the convex surface using the curvature characteristics of this surface, thus entering the gaps between the arc-extinguishing grids 5, achieving multi-stage arc segmentation. Furthermore, the inwardly extending end of the arc-extinguishing grid 5 can be constructed into various curved structures, including arc shapes, whose spatial positions cooperate with the first arc-initiating plate 4 and the second arc-initiating plate 6 to jointly guide and segment the arc into the gaps between the arc-extinguishing grids.

[0046] Figures 6 to 10 Other shapes and structures of the first arc-inducing plate 4 and the second arc-inducing plate 6 in this utility model are shown. The first arc-inducing plate 6 is symmetrically fixedly installed on both sides of the stationary contact 2. Its structural form also includes a curved plate shape. The second arc-inducing plate 10 is fixedly disposed at the bottom of the insulating shell 1 and located on both sides of the movement trajectory of the moving contact 6. Its structural form also includes a curved plate shape. Its function is to guide the initial arc generated when the contact separates into the gap of the arc-extinguishing grid array 5 and to limit the arc from spreading to the bottom. Figure 6 The arc-extinguishing grid plate 5 is a rectangular flat plate with a stepped decreasing arrangement along the contact breaking direction, and the outer ends are connected to form a line. Figure 7 The middle arc-extinguishing grid plate 5 has a rectangular flat plate configuration, arranged in a stepped decreasing manner along the contact breaking direction, and the outer ends are connected to form an arc shape. Figure 8 The middle arc-extinguishing grid plate 5 has a rectangular flat plate configuration, and the length of the arc-extinguishing grid plate 5 is set to a fixed and equal length. Figure 9 The middle arc-extinguishing grid plate 5 has a folded plate configuration. Figure 9 The arc-extinguishing grid 5 is a curved panel configuration.

[0047] In some embodiments, the insulating shell 1 is made of epoxy resin or ceramic, and the interior is a vacuum or filled with gas, including one or any combination of air, SF6, hydrogen and nitrogen.

[0048] In some embodiments, the body material of the first arc-starting plate 4 and the second arc-starting plate 6 is made of nickel-iron alloy, copper-tungsten alloy or copper-chromium alloy; the arc-extinguishing grid plate 5 is made of POM, PMMA, nylon, ceramic, copper or iron.

[0049] The working principle of this invention is as follows: When the switching device receives an external disconnection command, the moving contact and the stationary contact begin to separate. During the separation of the moving and stationary contacts, the initial arc generated between the contacts is first guided to the surface of the first or second arc-initiating plate by the Lorentz force generated under the action of the external magnetic field of the arc-extinguishing chamber, and then moves directionally along its surface to the end of the arc-initiating plate. After being accelerated at the end of the arc-initiating plate, the arc is forcibly driven into the parallel array gap formed by the arc-extinguishing grid plates. In this process, the arc is divided into multiple short arc units connected in series by the parallel array of arc-extinguishing grid plates. By increasing the arc voltage drop, the arc voltage is significantly increased, accelerating the extinction of the arc.

[0050] This invention utilizes a dual-stage arc-initiating plate with coordinated magnetic field control and optimized arc-extinguishing grid structure and spatial layout. By dividing the arc into multiple short-arc units connected in series using the arc-extinguishing grid, it significantly increases the arc voltage by increasing the arc voltage drop, accelerates the effective arc voltage establishment process, significantly improves the arc directional movement speed and the arc-cutting efficiency of the arc-extinguishing grid, accelerates arc extinguishing, significantly improves the arc voltage at the time of breaking, and constructs an effective artificial zero-crossing point. This enables a short-circuit current breaking capacity with high reliability and high breaking capacity.

[0051] Example 2

[0052] This embodiment discloses an interruption device, such as... Figure 11As shown, its topology includes a main current-carrying branch, a transfer branch, and an overvoltage limiting branch connected in parallel. The main current-carrying branch is composed of one or more fast mechanical switches connected in series, formed by the magnetic blowout arc-extinguishing chamber in Embodiment 1. The transfer branch is composed of one or more high-capacity power electronic modules connected in series. The overvoltage limiting branch includes a metal oxide surge arrester. Under normal system operation, current flows through the main current-carrying branch, and the high-capacity power electronic module in the transfer branch is in the off-state. When a short-circuit fault occurs or a tripping command is received from the control system, the moving and stationary contacts of the switching device open, generating an arc between the contacts. At this time, the thyristor in the external magnetic blowout circuit is triggered, and the high-capacity power electronic module remains in the conducting state. The external magnetic blowout circuit begins to discharge, the arc in the switching device on the main current-carrying branch burns, and under the influence of the magnetic blowout from the external magnetic blowout component, and with the spatial coordination of the first and second arc-initiating plates, it accelerates along the surface of the arc-initiating plate into the arc-extinguishing grid. After being cut by the arc-extinguishing grid, the body arc voltage rapidly increases, driving the short-circuit current from the main current-carrying branch to the transfer branch, achieving rapid natural commutation. When the short-circuit current is completely transferred to the transfer branch, the current in the main current-carrying branch crosses zero, extinguishing the arc. When the gap between the moving and stationary contacts of the breaking device can withstand the transient recovery voltage generated by the transfer branch, the high-capacity power electronic module is shut down, and the short-circuit current is transferred to the metal oxide surge arrester in the overvoltage limiting branch, dissipating system energy and completing the entire breaking process.

[0053] Example 3

[0054] This embodiment discloses an interruption device, such as... Figure 12 As shown, its topology includes a main current-carrying branch, a transfer branch, and an overvoltage limiting branch connected in parallel. The main current-carrying branch is composed of one or more switching devices from Embodiment 1 connected in series. The transfer branch is composed of an oscillating capacitor and an inductor, or only includes an oscillating capacitor. The overvoltage limiting branch includes a metal oxide surge arrester. Under normal system operation, current flows through the current-carrying branch. At this time, there is no voltage on the capacitor in the transfer branch, and the overvoltage limiting branch, containing the metal oxide surge arrester, has not reached its switching threshold, so no current flows through it. When a short-circuit fault occurs in the system or a tripping command is received from the control system, the moving and stationary contacts of the breaking device open, generating an electric arc between the contacts and triggering the thyristor in the external magnetic blow-out circuit to conduct. The external magnetic blow-out circuit begins to discharge, and the electric arc in the breaking device on the main current branch burns. Under the influence of the magnetic blow-out of the external magnetic blow-out component, it begins to accelerate along the surface of the first and second arc-initiating plates and enters the arc-extinguishing grid. After being cut by the arc-extinguishing grid, the body arc voltage oscillates and increases, resonating with the oscillating capacitor C and inductor L in the transfer branch. The current in the transfer branch continuously increases, forcing the current in the main current branch to cross zero and extinguishing the arc. The short-circuit current is transferred to the transfer branch to charge the capacitor. When the inter-terminal voltage reaches the metal oxide arrester's turn-on threshold, the overvoltage limiting branch conducts, the system energy is dissipated, and the entire breaking process is completed.

[0055] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A magnetic blowout arc extinguishing chamber, characterized in that: include: Insulating outer casing (1); Two conductive rods (8) are respectively inserted into the top and bottom of the insulating shell (1); The stationary contact (2) and the moving contact (7) are respectively connected to the ends of the two conductive rods (8) away from the insulating shell (1); The bellows (3) is slidably sleeved on the moving contact (7) and connected to the bottom of the insulating shell (1); Multiple arc-extinguishing grid plates (5) are connected to both sides of the inner wall of the insulating shell (1) and form a parallel array; The first arc-leading piece (4) is connected to both sides of the stationary contact (2); The second arc-starting piece (6) is disposed at the bottom of the insulating shell (1) and located on both sides of the movement trajectory of the moving contact (7); The magnetic blow-out component (9) is disposed outside the insulating housing (1).

2. The magnetic blowout arc extinguishing chamber according to claim 1, characterized in that: The arc-extinguishing grid (5) has the shape of a flat plate, a folded plate, and a curved plate. The end of the arc-extinguishing grid (5) away from the insulating shell (1) is generally straight, arc-shaped, or umbrella-shaped.

3. The magnetic blowout arc extinguishing chamber according to claim 1, characterized in that: The insulating shell (1) is made of epoxy resin or ceramic and is filled with a vacuum or gas, the filling gas including one or any combination of air, SF6, hydrogen and nitrogen.

4. The magnetic blowout chamber of claim 1, wherein: The first arc-starting plate (4) and the second arc-starting plate (6) are made of nickel-iron alloy, copper-tungsten alloy or copper-chromium alloy; the arc-extinguishing grid plate (5) is made of POM, PMMA, nylon, ceramic, copper or iron.

5. The magnetic blowout arc-extinguishing chamber according to claim 1, characterized in that: The first arc-inducing plate (4) and the second arc-inducing plate (6) have structural forms including straight plate and curved plate.

6. The magnetic blowout arc extinguishing chamber according to claim 1, characterized in that: The length of the arc-extinguishing grid plate (5) is set to a fixed equal length, or arranged in a stepped decreasing manner along the contact breaking direction.

7. The magnetic blowout arc extinguishing chamber according to claim 1, characterized in that: The magnetic blowout component (9) includes: Pre-charged capacitor (91); The discharge thyristor (92) is connected at one end to the positive terminal of the pre-charge capacitor (91); The arc-blowing coil (93) has one end connected to the other end of the discharge thyristor (92) and the other end connected to the negative terminal of the pre-charge capacitor (91). A freewheeling diode (94) is connected in parallel across the arc-blowing coil (93).

8. The magnetic blowout arc extinguishing chamber according to claim 1, characterized in that: The inner wall of the insulating shell (1) is provided with a slot, and the end of the arc-extinguishing grid plate (5) extends into the slot.

9. A switching device, characterized in that: This includes the main current-carrying branch, the transfer branch, and the overvoltage limiting branch connected in parallel; The main flow branch is composed of one or more fast mechanical switches connected in series based on the magnetic blowout arc extinguishing chamber according to any one of claims 1 to 8; The transfer branch is composed of one or more high-capacity power electronic modules connected in series. The overvoltage limiting branch includes a metal oxide surge arrester.

10. A switching device, characterized in that: This includes the main current-carrying branch, the transfer branch, and the overvoltage limiting branch connected in parallel; The main flow branch is composed of one or more fast mechanical switches connected in series based on the magnetic blowout arc extinguishing chamber according to any one of claims 1 to 8; The transfer branch is composed of an oscillating capacitor and an inductor connected in series; The overvoltage limiting branch includes a metal oxide surge arrester.

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