CN110504117A - A T-shaped symmetrical double-helix self-excited magnetic blowing arc extinguishing device - Google Patents

Abstract

The invention discloses a T-shaped symmetrical double-helix self-excited magnetic blowout arc extinguishing device, which includes relatively symmetrically arranged conductive bars, the lower ends of which are respectively connected with the front arc-leading bar and the rear arc-leading bar, and the lower ends of the rear arc-leading bar are It is connected with the static contact, the lower end of the leading arc bar is connected with one end of the exciting helical bar, and the other end of the exciting helical bar is connected with the lower busbar through the return bar; The ends are respectively connected with the magnetically conductive connecting plate, and the upper end of the magnetically conductive connecting plate abuts against the bottom of the front leading arc row. The invention can solve the problems of poor breaking capacity and poor arc blowing effect of the DC fast circuit breaker in the prior art, and has strong breaking capacity, long service life and high reliability.

Description

A T-shaped symmetrical double-helix self-excited magnetic blowing arc extinguishing device

technical field

The invention relates to a switching device, in particular to a T-shaped symmetrical double-helix self-excited magnetic blow-out arc extinguishing device.

Background technique

At present, many important industries such as urban rail transit, mining, metallurgy, and ship power in China have adopted DC power supply systems. As the most important protection device in the DC power supply system, the DC fast circuit breaker must have the ability to reliably switch on and off normal current and abnormal current (such as short circuit), and must also meet the temperature requirements for long-term operation. As the load capacity of DC power supply continues to increase, the current when a short-circuit fault occurs in the system often reaches nearly 100,000 amperes, and it becomes extremely difficult to break the large-capacity DC fast circuit breaker. and reliability have put forward high requirements.

A DC circuit breaker is a key component for disconnecting faulty lines and protecting electrical equipment, and its breaking performance is the most important and basic technical index that characterizes operating characteristics. The electrical life of a circuit breaker, generally speaking, is the service life of the circuit breaker, which refers to the reliable on-off times of the circuit breaker when the rated current is passed. When the switch is turned off, an arc will be generated on the moving and static contacts, and the arc will cause the wear of the contact material, thereby reducing the electrical life of the circuit breaker.

There are following four major defects in the existing direct current fast circuit breaker:

1. With the continuous increase of DC power supply load capacity, the current in the event of a short-circuit fault in the system often reaches nearly 100,000 amperes, and the breaking of the circuit breaker becomes extremely difficult. At present, most of the products at home and abroad have the breaking capacity of the circuit breaker Only 80kA, it is difficult to meet the breaking requirements of the existing DC power supply system for the circuit breaker.

2. The arc blowing effect of the magnetic blowing arc extinguishing system. When the system generates a large fault current, the arc blowing effect of the existing magnetic blowing system is difficult to make the DC circuit breaker break normally.

3. When the fault current occurs frequently, the number of tripping of the circuit breaker increases, which puts forward higher requirements for the mechanical life and electrical life of the circuit breaker. Improving the mechanical life and electrical life of circuit breakers has also become the development trend of the circuit breaker industry.

Fourth, circuit breakers also have high requirements for materials. How to select and manufacture materials that meet the conditions of use, and how to detect whether the parts are qualified are also one of the difficulties.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a T-shaped symmetrical double-helix self-excited magnetic blowout arc that can solve the problems of poor breaking capacity and poor arc blowing effect of the DC fast circuit breaker in the prior art device.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

Provided is a T-shaped symmetrical double-helix self-excited magnetic blowout device, which includes relatively symmetrical conductive bars, the lower ends of which are respectively connected to the front and rear arc bars, and the lower ends of the rear arc bars are connected to static arc bars. The contact is connected, the lower end of the leading arc bar is connected with one end of the exciting helical bar, and the other end of the exciting helical bar is connected with the lower busbar through the return bar; It is connected with the magnetic connecting plate, and the upper end of the magnetic connecting plate is in contact with the bottom of the front leading arc row; a magnetic conducting plate is arranged between the front leading arc row and the rear leading arc row, and the lower part of the magnetic conducting plate is connected with the magnetic connecting plate; A moving contact is arranged under the front arc striker, the middle part of the moving contact is hinged with the side wall of the arc extinguishing device, the lower part of the static contact is connected with the upper outlet pile, and the lower part of the moving contact is connected with the lower outlet pile; An arc extinguishing grid is arranged on the upper side.

In the above technical solution, preferably, the magnetic guide plate is perpendicular to the front arc leading row and the rear arc leading row.

In the above technical solution, preferably, there are two magnetically conductive plates, which are symmetrical about the connecting plane of the center line of the front arc-leading row and the rear arc-leading row.

In the above technical solution, preferably, the cross-sections of the front and rear arc strike rows are broken lines, the upper and middle parts of the front and rear arc strike rows are perpendicular to each other, and the front arc strike row and the rear arc strike row are perpendicular to each other. The middle part of the row is located on the same horizontal plane, and the distance between the bottom of the leading arc row and the rear leading arc row is less than the distance between the middle part of the leading arc row and the rear leading arc row.

In the above technical solution, preferably, the lower end of the front leading arc row is bent backwards, and the bent part is connected to one end of the exciting helical row.

In the above technical solution, preferably, the side where the upper part of the movable contact deviates from the fixed contact abuts against the shift fork.

In the above technical solution, preferably, a stopper is provided on a side adjacent to the fixed contact on the upper part of the movable contact.

In the above technical solution, preferably, the upper end of the stopper is flush with the upper surface of the movable contact, and the lower end of the stopper is at the same height as the lower end of the rear arc-leading row.

In the above technical solution, preferably, the exciting helical row has a double helix structure, and the magnetically conductive plate is T-shaped.

In the above technical solution, preferably, the material of the shift fork and the stopper is high-strength alloy steel; the material of the moving contact and the static contact is silver-based alloy; the material of the shell is high-performance SMC composite material.

The main beneficial effects of the above-mentioned T-shaped symmetrical double-helix self-excited magnetic blowout device provided by the present invention are:

In the present invention, the static contact assembly is composed of the rear arc strike row and the static contact, and the magnetic blow assembly is composed of the front arc strike row and the excitation helical row. During normal operation, the static contact and the moving contact are overlapped, and the working current flows in through the upper outlet pile, and flows out through the static contact, the moving contact and the lower outlet pile in turn, thus forming the main conductive circuit.

When a fault occurs, the magnetic field pulls the moving contact, which separates the moving contact from the static contact and generates an arc. After the fault current passes through the rear arc bar and the static contact, an excitation magnetic field is generated on the excitation core, and the magnetic field is adjacent to the static contact. The contact and the moving contact form an upward arcing force on the arc generated by the separation of the static contact and the moving contact, so that the arc moves upward from the static contact and the moving contact to the front arc striker and the rear arc striker. .

The arc jumps to the front arc bar, and then flows through the excitation helical bar. One part enters the lower bus bar through the return bar, and the other part is conducted to the magnetic plate through the excitation core and the magnetic connecting plate. A magnetic field is generated in between, the magnetic field attracts the arc and quickly drives the arc root to move upward along the front arc row and the rear arc row, because the distance between the lower part of the front arc row and the rear arc row is smaller than the middle of the front arc row and the rear arc row The arc is elongated, and the arc is guided to quickly enter the arc extinguishing grid. The arc extinguishing grid divides the arc into multiple sections to generate a constant overvoltage. In a very short time, the arc is quickly extinguished and the fault current is broken. ; It and the current flow out through the conductive row.

Thus, the rear arcing row, the front arcing row, the excitation helical row, and the return row form the excitation fault current circuit, and the excitation core, the magnetic connecting plate, and the T-shaped magnetic conducting plate form the excitation circuit. Since the excitation circuit uses the dominant The fault current generated by the electric circuit, when the current is reversed, the magnetic field is also reversed, and the upward force on the arc is always maintained, thus realizing non-polarity bidirectional breaking, thereby significantly improving the application range of DC fast circuit breakers, reliable Sex is also higher.

By setting the excitation fault current circuit, the closing and breaking characteristics of the arc extinguishing device under short-circuit conditions have been greatly improved, reaching 100kA, which meets the requirements for the breaking capacity of DC circuit breakers in existing subway and other working conditions.

By separating the excitation fault current circuit from the main conductive circuit, and realizing the arc extinguishing function through the excitation circuit and the arc extinguishing grid, so as to ensure its good arc extinguishing effect, it not only protects the contact system of the circuit breaker, but also improves the circuit breaker. The reliability of normal breaking for short-circuit current.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic diagram of the connection relationship between the return row and various components.

Fig. 3 is a schematic diagram of the positional relationship between the magnetically conductive connecting plate and the magnetically conductive plate.

Among them, 1. Front lead arc bar, 2. Rear lead arc bar, 21. Static contact, 22. Lower busbar, 3. Moving contact, 31. Stopper, 32. Shift fork, 33. Upper outlet pile, 34, the lower outlet pile, 4, the excitation spiral row, 41, the excitation core, 5, the magnetic guide plate, 51, the magnetic conduction connecting plate, 52, the return row, 6, the arc extinguishing grid sheet, 61, the conductive row.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

As shown in FIG. 1 , it is a structural diagram of a T-shaped symmetrical double-helix self-excited magnetic blowout device.

The T-shaped symmetrical double-helix self-excited magnetic blowout device of the present invention includes a relatively symmetrically arranged conductive row 61, the lower ends of the conductive row 61 are respectively connected with the front arc starting row 1 and the rear arc starting row 2, and the lower ends of the rear arc starting row 2 It is connected with the static contact 21, the lower end of the front arc striker 1 is connected with one end of the excitation helical row 4, the excitation helical row 4 is a mutually symmetrical double helix structure, and the other end of the excitation helical row 4 is connected to the lower busbar 22 connection, as shown in Figure 2; the excitation core 41 is set inside the excitation helical row 4, and the two ends of the excitation core 41 are respectively connected with the magnetic connecting plate 51, and the upper end of the magnetic connecting plate 51 is connected with the front arc leading row 1 The bottom is abutted; a magnetic conductive plate 5 is arranged between the front arc-leading row 1 and the rear arc-leading row 2, the magnetic conductive plate 5 is T-shaped, and the lower part of the magnetic conductive plate 5 is connected with the magnetic conductive connecting plate 51, as shown in Figure 3; A moving contact 3 is arranged below the front arc striker 1, the middle part of the moving contact 3 is hinged to the side wall of the arc extinguishing device, the lower part of the static contact 21 is connected to the upper outlet pile 33, and the lower part of the moving contact 3 is connected to the lower outlet pile. 34 connection; the upper side of the magnetic conductive plate 5 is provided with an arc extinguishing grid sheet 6 .

Specifically, the magnetic guide plate 5 is perpendicular to the front arc leading row 1 and the rear arc leading row 2 . There are two magnetic guide plates 5, and they are symmetrical about the connecting plane of the center line of the front arc-leading row 1 and the rear arc-leading row 2.

The cross-sections of the front arc-leading row 1 and the rear arc-leading row 2 are broken lines, the upper and middle parts of the front arc-leading row 1 and the rear arc-leading row 2 are perpendicular to each other, and the front arc-leading row 1 and the rear arc-leading row 2 The middle part is located on the same horizontal plane, and the distance between the bottom of the front arc-leading row 1 and the bottom of the rear arc-leading row 2 is less than the distance between the middle part of the front arc-leading row 1 and the rear arc-leading row 2 .

The lower end of the front leading arc row 1 is bent backward, and the bent part is connected with the end of the excitation helical row 4 .

The upper part of the movable contact 3 abuts against the shift fork 32 on the side away from the fixed contact 21 . A stopper 31 is provided on the upper part of the movable contact 3 adjacent to the fixed contact 21 . The upper end of the block 31 is flush with the upper surface of the movable contact 3 , and the height of the lower end of the block 31 is the same as that of the lower end of the rear arc-leading row 2 . During normal operation, the block 31 abuts against the rear arc bar 2 adjacent to the static contact 21; when resetting from a fault, the shift fork 32 pushes the moving contact 3 back to the position where it contacts the rear arc bar 2 place.

Preferably, the DC fast circuit breaker corresponding to the arc extinguishing device provided by this solution uses a permanent magnet mechanism to realize the opening and closing operation, while the electromagnetic mechanism of the existing circuit breaker mostly uses permanent magnet materials for magnetic holding. When the circuit breaker When performing the opening operation, it is necessary to generate a reverse magnetic field through the electromagnetic coil to offset the magnetic field of the permanent magnet. During frequent operations, the permanent magnet will demagnetize, and the closing holding force will decrease accordingly, reducing the circuit breaker's safety. reliability.

Preferably, the excitation core 41 is made of ferrite material. Therefore, in this scheme, when the closing operation is performed, the electromagnetic coil, that is, the excitation helical row 4 generates an electromagnetic field, drives the excitation core 41 to move and completes the closing operation, and when the current of the excitation helical row 4 is disconnected, the external magnetic field disappears. The magnetism of the excitation core 41 still remains the same as when it is saturated. When the gate is opened, the excitation helical row 4 generates a reverse magnetic field, and the excitation core 41 is demagnetized to realize the gate opening.

The traditional permanent magnet mechanism makes the moving iron core move along the axis direction in the permanent magnet housing by changing the current direction of the electromagnetic coil. When the moving iron core moves to one end of the permanent magnet housing, the magnetic force keeps the iron core at this end The position, the size of the holding force depends on the magnetic field strength of the permanent magnet.

Preferably, the material of the shift fork 32 and the stopper 31 is high-strength alloy steel, and a special process is adopted for surface treatment. The parts have low internal stress, high toughness, good lubricity, high hardness, and wear resistance And other characteristics, so that the mechanism operates reliably. In the preliminary test and type test of the circuit breaker, the mechanical life is more than 200,000 times.

Preferably, the material of the movable contact 3 and the static contact 21 is a silver-based alloy. Through the pre-oxidation-sintering-extrusion manufacturing process, a dense structure can be formed on the contact surface, which has high chemical stability and corrosion resistance. It has high performance such as arc burn resistance and fusion welding resistance. With the self-designed magnetic blowing arc extinguishing system, the arc can be extinguished quickly. The electrical life of the circuit breaker can reach more than 1000 times, and the contact resistance of the main circuit is lower than 25μΩ .

Preferably, the shell is made of high-performance SMC composite material, which has extremely high strength, and has excellent electrical insulation performance, thermal stability and chemical corrosion resistance. The insulating parts of the main frame adopt a flat structure, which reduces the complexity of the molding die and can effectively avoid major defects such as lack of material and air holes that usually occur in complex parts.

Preferably, the shell is set as a plate structure, which simplifies the compression molding process, and thus long fiber reinforcements can be added to the material, greatly improving the overall performance of the molding parts. Modular design, each functional unit is completely independent and can be assembled separately, greatly improving work efficiency and product quality stability.

Preferably, the copper conductive parts including the conductive row 61, the front arc striker 1, and the rear arc striker 2 are all forged, which not only improves the processing performance of the material, improves the dimensional accuracy of the parts, but also increases the precision of the conductive parts. strength and electrical conductivity. The surface of the copper conductive parts is treated with silver plating, and the thickness of the silver plating is greater than 12 μm.

The specific embodiments of the present invention are described above so that those skilled in the art can understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are included in the protection list.

Claims (10)

1. a kind of symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type, which is characterized in that the conduction including relative symmetry setting Row, busbar lower end connect with preceding striking row and rear striking row respectively, and rear striking row lower end is connect with static contact, under preceding striking row The one end arranged with excitation spiral is held to connect, the other end of excitation spiral row is connect by the row of reflux with lower busbar；Excitation spiral row It is inside arranged with field core, the both ends of field core are connect with magnetic conduction connecting plate respectively, and bottom is arranged in the upper end of magnetic conduction connecting plate and preceding striking Portion abuts；It is provided with magnetic conductive board between preceding striking row and rear striking row, the lower part of magnetic conductive board is connect with magnetic conduction connecting plate；Under preceding striking row Side is provided with moving contact, and moving contact middle part is hinged with the side wall of outer shell of arc-control device, and static contact lower part is connect with upper outlet stake, moves The lower part of contact is connect with lower outlet stake；Arc extinguishing grid pieces are provided on the upside of magnetic conductive board.

2. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 1, which is characterized in that the magnetic conduction Plate is arranged with preceding striking, rear striking row is perpendicular.

3. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 2, which is characterized in that the magnetic conduction There are two plates, and the center line joint face about preceding striking row, rear striking row is symmetrical.

4. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 1, which is characterized in that the leading The cross section of arc row and rear striking row are in fold-line-shaped, and top, the middle part of preceding striking row and rear striking row are mutually perpendicular to respectively, preceding The middle part of striking row and rear striking row are located at same level, and preceding striking row lower part is less than preceding striking at a distance from rear striking row and arranges Middle part is at a distance from rear striking row.

5. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 4, which is characterized in that the leading The lower end of arc row is bent backward, and bending part is connect with one end that excitation spiral is arranged.

6. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 1, which is characterized in that the dynamic touching The side that static contact is deviateed on the top of head is abutted with shift fork.

7. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 6, which is characterized in that the dynamic touching The top of head is provided with block adjacent to the side of static contact.

8. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 7, which is characterized in that the block Upper end it is concordant with the upper surface of moving contact, height where the lower end of block is identical as height where rear striking row lower end.

9. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 1, which is characterized in that the excitation Spiral row is double-spiral structure, and magnetic conductive board is T-shaped.

10. the symmetrical double helix autoexcitation magnetic-quenching arc-extinguishing device of T-type according to claim 7, which is characterized in that the shift fork Material with block is high-strength alloy Steel material；The material of moving contact and static contact is silver-base alloy；The material of shell is height Performance SMC composite material.