High-voltage vacuum arc extinguishing unit based on asymmetric arc extinguishing chamber

Abstract

The invention discloses a high-voltage vacuum arc-extinguishing unit based on asymmetric arc-extinguishing chambers, which comprises two asymmetric vacuum arc-extinguishing chamber parts which are connected back to back, and comprises a static end, a movable end, a shielding cover and a shell, and is characterized in that the static end comprises a static end plate, a conductive core and a static contact; the moving end comprises a moving contact, a moving end plate and a conducting rod; the shielding case is connected with the shell, the static end and the moving end to form a closed structure; a conductive core is arranged on one surface of the static end plate; the other surface of the static end plate is connected with the static contact and the shielding cover; one end of the conducting rod is connected with the moving contact, and the other end of the conducting rod penetrates through the moving end plate and is connected with an external operating structure; according to the high-voltage vacuum arc-extinguishing chamber, a static conducting rod used in conventional design is replaced, the distance between the movable conducting rod and the static conducting rod is reduced, the characteristic size of the arc-extinguishing unit is reduced, and the manufacturing cost is greatly reduced; and the manufacturing difficulty and the engineering cost caused by geometric amplification of the single arc extinguish chamber can be reduced exponentially.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage electric power devices, and in particular to a high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber. Background Art

[0002] Vacuum switches are widely used due to their safety, reliability, environmental friendliness, and strong arc extinguishing ability. In the development of high-voltage transmission systems, especially those above 126kV, due to the saturation effect between the working voltage and contact distance of the vacuum switch arc extinguishing chamber, the conventional vacuum arc extinguishing chamber needs to be geometrically enlarged as the working voltage increases, making the arc extinguishing chamber production a technical bottleneck with extremely high cost and multi-directional impact limits. The use of multiple arc extinguishing chambers in series can improve the overall withstand voltage level of the circuit breaker, but this method makes the overall structure of the circuit breaker more complicated, and lacks synchronization and reliability, which further restricts development. Summary of the invention

[0003] The present invention provides a high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber to overcome the technical problem that due to the saturation effect between the operating voltage and the contact opening distance of the vacuum switch arc extinguishing chamber, as the operating voltage increases, the vacuum arc extinguishing switch structure is geometrically enlarged, which increases the manufacturing difficulty and engineering cost.

[0004] In order to achieve the above object, the technical solution of the present invention is:

[0005] A high-voltage vacuum arc-extinguishing unit based on an asymmetric arc-extinguishing chamber comprises two asymmetric vacuum arc-extinguishing chamber components connected back to back, the asymmetric vacuum arc-extinguishing chamber components comprising a static end, a dynamic end, a shielding cover and a shell, the static end comprising a static end plate, a conductive core and a static contact; the dynamic end comprising a dynamic contact, a dynamic end plate and a conductive rod; the shielding cover and the shell are connected with the static end and the dynamic end to form a closed structure;

[0006] A conductive core is provided on one side of the static end plate for conducting current; the other side of the static end plate is connected to the static contact and the shielding cover; the moving contact is arranged opposite to the static contact, and the conductive rod is perpendicular to the static end plate, one end of which is connected to the moving contact, and the other end passes through the moving end plate and is connected to the external operating structure.

[0007] Furthermore, it also includes two component connecting flanges, which are fixed on the static end plate, and two asymmetric vacuum interrupter components are connected through the component connecting flanges.

[0008] Furthermore, two voltage-equalizing capacitors are included;

[0009] One end of the two voltage-equalizing capacitors is connected to one end of the conductive rod, and the component connecting flange is used as the electrical parameter symmetry point, and the other ends of the two voltage-equalizing capacitors are connected to the same component connecting flange.

[0010] Furthermore, the size of the contact opening distance between the moving contact and the stationary contact in the high-voltage vacuum arc extinguishing unit is determined by the electric field strength and voltage of the high-voltage vacuum arc extinguishing unit, as shown in formula (1),

[0011]

[0012] Where k is a constant, C eq is the equivalent capacitance value of the voltage-equalizing capacitor, E is the set electric field strength, d is the contact opening distance, and V is the operating voltage.

[0013] Furthermore, the relationship between the axial electric field stress, electric field strength and voltage of the high-voltage vacuum arc extinguishing unit is as shown in formulas (2) and (3),

[0014] ε=KE (2)

[0015] ε=KV (3)

[0016] Among them, ε represents the axial electric field stress, K is a constant, and V represents the voltage.

[0017] Beneficial effects: The present invention provides a high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber. By designing two closed asymmetric vacuum arc extinguishing chamber components, the conductive core is arranged on the static end plate, and works together with the static contact on the static end plate to replace the static conductive rod used in the conventional design, thereby reducing the distance between the dynamic conductive rod and the static conductive rod, reducing the characteristic size of the designed arc extinguishing unit, and greatly reducing the manufacturing cost. Compared with conventional high-voltage vacuum arc extinguishing chambers of the same parameter level, connecting the two arc extinguishing chamber components back to back can keep the electric field stress within the linear distribution range, effectively reduce local stress concentration, and improve the high-voltage bearing capacity of the device. The axial electric field stress of the component is reduced by a multiple, so the device can multiply the manufacturing difficulty and engineering cost caused by the geometric enlargement of a single arc extinguishing chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A structural diagram of a high-voltage vacuum arc-extinguishing unit based on an asymmetric arc-extinguishing chamber provided by the present invention;

[0020] Figure 2 This is a schematic diagram of the asymmetric vacuum interrupter component of the present invention;

[0021] Figure 3 This is the principle structure diagram of a conventional high-voltage vacuum interrupter of the same parameter level;

[0022] Figure 4 This is a principle structural diagram of a vacuum arc extinguishing unit of a 126kV-GIS according to an embodiment of the present invention;

[0023] In the figure, 1. static end plate; 2. shielding cover; 3. moving contact; 4. porcelain shell; 5. porcelain shell sealing ring; 6. auxiliary shielding cover; 7. moving end plate; 8. bellows; 9. conductive rod; 10. mounting hole; 11. conductive core; 12. encapsulated asymmetric vacuum interrupter component; 13. component connecting flange; 14. equalizing capacitor; 15. static end; 16. shell; 17. static contact; 18. static conductive rod. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] This embodiment provides a high-voltage vacuum arc-extinguishing unit based on an asymmetric arc-extinguishing chamber, such as Figure 1 and Figure 2 As shown, it includes two asymmetric vacuum interrupter components, the asymmetric vacuum interrupter components include a static end and a dynamic end, the static end includes a static end plate 1, a conductive core 11 and a static contact 17; the dynamic end includes a dynamic contact 3, a dynamic end plate 7 and a conductive rod 9; the shielding cover 2 and the housing 16 are connected to the static end and the dynamic end to form a closed structure;

[0026] A conductive core 11 is provided on one side of the static end plate 1 for conducting current; the other side of the static end plate 1 is connected to the static contact 17 and the shielding cover 2; the moving contact 3 is arranged opposite to the static contact 17, and the conductive rod 9 is perpendicular to the static end plate 1, one end of which is connected to the moving contact 3, and the other end passes through the moving end plate 7 and is connected to the external operating structure.

[0027] Specifically, Figure 1 and Figure 3 As shown, the high-voltage vacuum arc extinguishing unit based on the asymmetric arc extinguishing chamber designed by the present invention is Figure 3The static end 15 and the static conductive rod 18 in the conventional vacuum arc extinguishing chamber insulation structure are directly led out by the static end plate 1 with the mounting hole 10, the conductive core 11 and the static contact 17, so as to realize the function of leading out the current of the static conductive rod 18 in the conventional design, and at the same time, the conductive cores 11 on both sides are connected, so as to achieve the design purpose of reducing the distance between the static conductive rod and the dynamic conductive rod, thereby reducing the size of the arc extinguishing unit; wherein Figure 1 The moving end in the embodiment also includes a porcelain shell 4, a porcelain shell sealing ring 5, an auxiliary shielding cover 6 and a bellows 8. The relationship between the shielding cover 2 and the moving end and the working principle are similar to Figure 3 The two encapsulated asymmetric arc extinguishing chamber components 12 are designed to be the same as conventional vacuum arc extinguishing chambers, and their characteristic dimensions are halved compared to conventional vacuum arc extinguishing chambers with the same parameters; a shell 16 is also provided outside the designed structure, which is connected to the shielding cover 2, and the designed shell prevents the inner wall of the insulating shell from being contaminated: when the contact gap arcs, a large amount of arc products such as metal vapor and metal ions will be generated. The shielding cover and the shell can effectively prevent these arc products from splashing onto the inner surface of the insulating shell, avoiding damage to the insulation performance of the insulating shell due to metal adhesion;

[0028] At the same time, the shield can cool, compound and condense the metal vapor and conductive particles in the shield. After the arc is extinguished, the arc products can be quickly cooled and condensed, which can speed up the recovery of the dielectric strength between the arc gaps and improve the breaking performance and working efficiency of the arc extinguishing chamber. Especially in the case of breaking high currents such as short-circuit currents, most of the heat energy generated by the arc will be absorbed by the shield, which not only helps to reduce the thermal damage of the arc to the contacts and other components, but also improves the dielectric recovery strength between the contacts, increases the breaking capacity of the vacuum arc extinguishing chamber, and ensures the safe and reliable operation of equipment such as circuit breakers;

[0029] In summary, the design of the conductive core and the static contact in the asymmetric vacuum arc extinguishing chamber component described in the present invention omits the structure of the key component of the conventional design, namely, the static conductive rod, thereby reducing the structural size and the distance between the moving and static contacts, i.e., the contact opening distance; at the same time, the design of the moving guide rod sharing the same axis on both sides enables the arc extinguishing chamber component to improve the mechanical stability and electrical performance of the device without increasing the additional geometric dimensions, thereby further realizing a compact structural design.

[0030] In a specific embodiment, Figure 1 and 2 As shown, it also includes two component connection flanges 13 and two voltage-grading capacitors 14. The component connection flanges 13 are fixed on the static end plate 1 through two mounting holes 10 provided on the static end plate 1, and two asymmetric vacuum interrupter components are connected through the component connection flanges 13;

[0031] One end of the two voltage-equalizing capacitors 14 is connected to one end of the conductive rod 9 , and the other ends of the two voltage-equalizing capacitors 14 are connected to the same component connecting flange 13 with the component connecting flange 13 as the electrical parameter symmetry point.

[0032] In this embodiment, a voltage-grading capacitor is designed, which is connected to the conductive rod and the static end to ensure uniform distribution of the electric field, reducing the problem of electric field concentration caused by increased spacing. The uniform electric field distribution enables efficient arc extinguishing performance to be achieved in a smaller structural size, while improving the compactness and stability of the device.

[0033] In a specific embodiment, the size of the contact opening distance between the moving contact 3 and the stationary contact 17 in the high-voltage vacuum arc extinguishing unit is determined by the electric field strength and voltage of the high-voltage vacuum arc extinguishing unit, as shown in formula (4):

[0034]

[0035] Where k is a constant, C eq is the equivalent capacitance of the voltage-equalizing capacitor, E is the electric field strength, d is the contact opening distance, and V is the applied voltage;

[0036] In conventional arc extinguishing chamber design, the contact distance d increases with the increase of voltage, and the electric field strength also increases accordingly. When the contact distance d increases to a certain extent, although the voltage continues to increase, the increase in the electric field strength E tends to saturate, that is, the saturation effect occurs. The relationship between the electric field strength and the contact distance in the conventional arc extinguishing chamber design is shown in formula (5):

[0037]

[0038] Among them, d is the distance between the arc extinguishing chamber contacts, U is the voltage, and when d increases to a certain threshold, the change of E tends to be flat;

[0039] By introducing the voltage-equalizing capacitor, the distribution of the electric field strength is more uniform, the voltage is more balanced, and the equivalent capacitance C of the voltage-equalizing capacitor is eq It will affect the electric field distribution and can maintain a higher electric field strength in a larger range. eq Under the same voltage, the contact opening distance is smaller than that of conventional designs, and the electric field strength is smaller. At the same time, because the length of the static conductive rod is saved, the voltage that can be withstood is higher than that of conventional designs under the same contact opening distance. The contact opening distance is obtained through saturation experiments. By continuously increasing the voltage, the value of the contact opening distance when the electric field is in the saturation effect is determined. The experiment shows that increasing the voltage of this device will cause the saturation effect of the electric field strength to appear more slowly, so that it can still maintain a high electric field strength when the opening distance is large.

[0040] In a specific embodiment, the relationship between the axial electric field stress, the electric field strength and the voltage of the high-voltage vacuum arc extinguishing unit is as shown in formulas (6) and (7),

[0041] ε=KE (6)

[0042] ε=KV (7)

[0043] Among them, ε represents the axial electric field stress, K is a constant, and V represents the voltage.

[0044] The axial electric field stress borne by the high-voltage vacuum arc extinguishing unit in the present invention is significantly reduced compared with the conventional arc extinguishing chamber design. It can be seen from formula (6) and formula (7) that its electric field stress is linearly related to the electric field strength, and therefore the electric field stress is linearly related to the voltage. Since the arc extinguishing unit is a back-to-back design, the axial electric field stress borne by the arc extinguishing unit designed in the present invention can be controlled to be about 50% of the original set voltage. The axial electric field stress can be maintained within the linear distribution range through the back-to-back design and electrical symmetry point optimization, which effectively reduces local stress concentration and improves the high-voltage bearing capacity of the device.

[0045] An embodiment of the device is as follows:

[0046] Sure Figure 1 The distance d between the static contact 17 and the moving contact 3 in the static end plate 1 is not greater than the saturation effect limit after the experiment, and the value of the electric field strength E of the main electric field of the vacuum gap is determined by the rated working voltage U; the length of the auxiliary shielding cover 6 is configured to make the static capacitance values ​​between the sealing rings 5 ​​(including the sealing rings and the static end plate 1 and the moving end plate 7) equal, or the external circuit is configured to make the working voltage of each porcelain shell U n (U n =U / 2n), by Figure 2 It can be seen that after the connection, the two conductive rods 9 of the high-voltage vacuum arc extinguishing unit are driven by the outer operating mechanism connecting rod (connected to the conductive rod 9), and are synchronously closed and opened along the same axis to complete the working task.

[0047] Taking the vacuum arc extinguishing unit applied to 126kV circuit breaker as an application example, the contact opening distance d = 30mm, the rated working voltage U = 126kV, and the electric field strength E of the main electric field are about 2.1kV / mm; the length of the auxiliary shielding cover 6 is configured to make the static capacitance value C between each sealing ring equal, or an external voltage equalizing circuit is configured to make the working voltage of each porcelain shell U n =31.5kV. The two conductive rods of the vacuum arc extinguishing unit are connected to the operating mechanism, so that they move synchronously toward each other along the same axis to close or move backward to open. The component connection flange is used as the symmetric point of electrical parameters and is connected to the moving end of the arc extinguishing unit with an equal value of PF-level high-voltage film equalizing capacitor; the component connection flange is also the mechanical base point of bidirectional operation, which can offset the closing momentum of the moving contact of the tube and increase the stability of the mechanism operation. Figure 4 The principle structure of the arc extinguishing unit of 126kV-GIS using this device to replace SF6 circuit breaker.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber, characterized in that: The invention comprises two asymmetric vacuum interrupter components connected back to back, wherein the asymmetric vacuum interrupter components comprise a static end, a dynamic end, a shielding cover (2) and a housing (16), wherein the static end comprises a static end plate (1), a conductive core (11) and a static contact (17); the dynamic end comprises a dynamic contact (3), a dynamic end plate (7) and a conductive rod (9); the shielding cover (2) is connected to the housing (16), the static end and the dynamic end to form a closed structure; A conductive core (11) is provided on one side of the static end plate (1) for conducting current; the other side of the static end plate (1) is connected to the static contact (17) and the shielding cover (2); the moving contact (3) is arranged opposite to the static contact (17); the conductive rod (9) is perpendicular to the static end plate (1), one end of which is connected to the moving contact (3), and the other end of which passes through the moving end plate (7) and is connected to an external operating structure.

2. A high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber according to claim 1, characterized in that: It also comprises two component connection flanges (13), wherein the component connection flanges (13) are fixed on the static end plate (1), and two asymmetric vacuum interrupter components are connected via the component connection flanges (13).

3. A high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber according to claim 2, characterized in that: Also includes two voltage grading capacitors (14); One end of the two voltage-equalizing capacitors (14) is connected to one end of the conductive rod (9), and the other end of the two voltage-equalizing capacitors (14) is connected to the same component connecting flange (13) with the component connecting flange (13) as the electrical parameter symmetry point.

4. A high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber according to claim 3, characterized in that: The size of the contact opening distance between the moving contact (3) and the stationary contact (17) in the high-voltage vacuum arc extinguishing unit is determined by the electric field strength and voltage of the high-voltage vacuum arc extinguishing unit, as shown in formula (1), Where k is a constant, C eq is the equivalent capacitance value of the voltage-equalizing capacitor, E is the set electric field strength, d is the contact opening distance, and V is the operating voltage.

5. A high-voltage vacuum arc extinguishing unit based on an asymmetric arc extinguishing chamber according to claim 4, characterized in that: The relationship between the axial electric field stress, electric field intensity and voltage of the high-voltage vacuum arc extinguishing unit is shown in formulas (2) and (3): ε=KE (2) ε=KV (3) Among them, ε represents the axial electric field stress, K is a constant, and V represents the voltage.

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