Insulated reinforced contact box for 17.5 kV removable metal-enclosed switchgear

Abstract

The utility model discloses an insulation reinforced contact box for 17.5 kV removable metal-enclosed switchgear, which comprises a contact box, a metal plate wall and a busbar, the bottom end of the contact box is provided with a mounting seat, the front part of the contact box is provided with an insulation tongue, and one end of the insulation tongue is provided with an extension tongue; the contact box is connected with the metal plate wall through the mounting seat, the metal plate wall is bent towards the X direction, and the side, provided with the mounting boss, of the mounting seat is in contact with the side, in the bending direction, of the metal plate wall, so that the creepage distance is increased, and the electrical performance is improved; the contact box adopts an unusual board-front installation mode, so that the internal insulation creepage distance is increased, and the internal insulation performance is obviously improved; the arrangement of the extension tongue can shield the grounding installation part of the installation boss part, so that the exposed live-line distance of the installation part can meet the 17.5 kV voltage grade requirement, the design can block high voltage, the air insulation of the high-voltage busbar to the ground is changed into composite insulation, and the reliable electrical performance is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of contact box technology, specifically relating to an insulated reinforced contact box for a 17.5kV withdrawable metal-enclosed switchgear. Background Technology

[0002] There are two operating modes for AC power systems: directly grounded neutral point and indirect grounded neutral point. Each mode has its own advantages and disadvantages. When the neutral point is directly grounded or grounded through low impedance, a single-phase ground fault results in a large fault current and near-zero voltage, while the voltage of the non-faulty phases remains unchanged. This disrupts the three-phase symmetry, making the fault current easy to determine, and protection devices can quickly disconnect the circuit. When the neutral point is ungrounded or grounded through high impedance (such as an arc suppression coil), a single-phase ground fault results in a smaller fault current and lower voltage, while the voltage of the non-faulty phases rises to the line voltage. In this case, fault location is difficult, and the system can operate with the fault for a short period, but the power supply reliability is improved.

[0003] In my country, power systems above 40.5kV mostly use directly grounded neutral systems, while medium-voltage systems of 40.5kV and below mostly use indirectly grounded neutral systems. These two systems have different insulation requirements, leading to different designs for insulation components. Since most foreign medium-voltage systems use 17.5kV and primarily employ directly grounded neutral, the contact boxes currently available on the domestic market for withdrawable switchgear only meet the needs of this single system; that is, the creepage distance of the contact box only meets the phase voltage requirements. Utility Model Content

[0004] The purpose of this invention is to provide an insulated reinforced contact box for a 17.5kV withdrawable metal-enclosed switchgear, in order to solve the problem of creepage insulation during installation of contact boxes in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An insulated reinforced contact box for a 17.5kV withdrawable metal-enclosed switchgear includes a contact box, a sheet metal wall, and a busbar. The bottom of the contact box has a mounting base, and the front of the contact box has an insulating tongue with an extension tongue at one end. The contact box is connected to the sheet metal wall via the mounting base.

[0007] Furthermore, the mounting base is rectangular, with mounting bosses on its four corners. The sheet metal wall is bent to one side, and the sheet metal wall has holes that mate with the mounting bosses. The side of the mounting base with the mounting bosses contacts the side of the sheet metal wall that is bent.

[0008] Furthermore, the mounting boss is covered with a metal cover, and a mounting screw hole is provided inside the mounting boss, with a bolt installed inside the mounting screw hole.

[0009] Furthermore, the contact box is composed of a front end and a rear end, the rear end being cylindrical and the front end being tapered.

[0010] Furthermore, the inner wall of the tail end is equidistantly distributed with several inner umbels, and the outer wall of the front end is equidistantly distributed with several outer umbels. The inner umbels are arranged in a 360° circumferential configuration, while the outer umbels are arranged in a 180° circumferential configuration. The outer umbels face the same direction as the insulating tongue and are symmetrically centered with respect to the insulating tongue. The outer umbels ensure that the creepage distance outside the contact box meets the requirements of a neutral point non-directly grounded system, and can withstand line voltage without insulation failure. Similarly, the inner umbels increase the creepage distance inside the contact box, meeting the requirements of a neutral point non-directly grounded system, and preventing surface discharge or breakdown problems due to the phase voltage rising to the line voltage during a single-phase short circuit.

[0011] Furthermore, the busbar is installed inside the insulating tongue, and a stationary contact is attached to one side of the busbar. The stationary contact has a countersunk hole, and a threaded hole concentrically fitted to the countersunk hole is formed at the bottom of the contact box. A bolt is installed inside the countersunk hole of the stationary contact, and the bolt passes through the busbar and enters the threaded hole. Tightening the bolt stabilizes the connection of the busbar.

[0012] The technical solution of this utility model has the following beneficial effects:

[0013] 1. The sheet metal wall is bent in the X direction, and the side of the mounting base with the mounting boss contacts the side of the sheet metal wall in the bending direction. This mounting method increases the creepage distance and improves electrical performance. The contact box adopts an unusual front-mounted method, which increases the internal insulation creepage distance and significantly improves the internal insulation performance.

[0014] 2. The extension tongue can cover the grounded mounting components of the mounting boss, ensuring that the exposed live distance meets the requirements of the 17.5kV voltage level. This design can block high voltage, transforming the air insulation of the high-voltage busbar to ground into composite insulation, thus guaranteeing reliable electrical performance. The insulating tongue and extension tongue, positioned between the busbar and the bolt, both increase the creepage distance and provide insulation, significantly improving electrical performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] Figure 2 This is a schematic diagram of the contact box structure of this utility model.

[0018] Figure 3 This is a cross-sectional view of the contact box installation of this utility model.

[0019] Figure 4 This is a prior art installation diagram of the present utility model.

[0020] Figure 5 This is a cross-sectional view of the contact box of this utility model.

[0021] Figure 6 This is an enlarged view of section A of this utility model.

[0022] Reference numerals: 10, contact box; 101, front end; 102, tail end; 11, mounting base; 12, insulating tongue; 121, extension tongue; 13, mounting boss; 131, mounting screw hole; 14, metal cover; 15, bolt; 16, stationary contact; 17, countersunk hole; 171, threaded hole; 18, inner umbel skirt; 19, outer umbel skirt; 20, busbar; 30, sheet metal wall. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0024] For ease of description, the X and Y axes are used to represent directions in the diagram; the X direction is not mandatory, and this patent can guarantee the electrical distance required for 17.5kV even in the Y direction, whereas ordinary systems can only guarantee this in the X direction.

[0025] Example 1:

[0026] refer to Figures 1-5 An insulated reinforced contact box for a 17.5kV withdrawable metal-enclosed switchgear includes a contact box 10, a sheet metal wall 30 and a busbar 20. The bottom of the contact box 10 has a mounting base 11, and the front of the contact box 10 has an insulating tongue 12. One end of the insulating tongue 12 has an extension tongue 121.

[0027] Contact box 10 is connected to sheet metal wall 30 via mounting base 11;

[0028] The mounting base 11 is rectangular, and mounting bosses 13 are provided on the four corners of the mounting base 11. The sheet metal wall 30 is bent in one direction (X direction in the figure). The sheet metal wall 30 has holes that cooperate with the mounting bosses 13. The side of the mounting base 11 with mounting bosses 13 contacts the side of the sheet metal wall 30 in the bending direction for installation.

[0029] In the above scheme, the extension tongue 121 can block the grounded mounting component of the mounting boss 13 (manifested as...). Figure 3 The T electrical distance in the design ensures that the exposed live distance meets the requirements of the 17.5kV voltage level. This design can block high voltage and transform the air insulation of the high voltage busbar to ground into composite insulation, thus ensuring reliable electrical performance.

[0030] Furthermore, because the sheet metal wall 30 is bent in the X direction, the side of the mounting base 11 with the mounting boss 13 contacts the side of the sheet metal wall 30 in the bending direction for installation, which is manifested as Figure 3 The L electrical distance in the mounting method increases the creepage distance and improves electrical performance; the contact box 10 adopts an unusual front-panel mounting method, which increases the internal insulation creepage distance and significantly improves the internal insulation performance.

[0031] Referring to existing technology Figure 4 Compared with the installation method of the ordinary 12kV contact box 10, it can be clearly seen that the design creepage distance is too small. The installation structure causes the electrical distance (L dimension) of the high voltage bus to be greatly shortened, which cannot meet the requirements of the 17.5kV voltage level.

[0032] Specifically, the contact box 10 is passed through the sheet metal wall 30, and the mounting boss 13 cooperates with the hole opened in the sheet metal wall 30 to achieve preliminary positioning and installation.

[0033] Further reference Figure 5 The mounting boss 13 is covered with a metal cover 14, and the mounting boss 13 has a mounting screw hole 131 inside, and a bolt 15 is installed inside the mounting screw hole 131.

[0034] In a further embodiment, the bolt 15 is passed through the metal cover 14 and inserted into the mounting screw hole 131, and the bolt 15 is tightened to complete the installation of the contact box 10.

[0035] refer to Figure 2 The contact box 10 consists of a front end 101 and a rear end 102. The rear end 102 is cylindrical, and the front end 101 is tapered.

[0036] Example 2 (in conjunction with Example 1):

[0037] refer to Figure 3 and Figure 5 Several inner umbrella skirts 18 are evenly distributed on the inner wall of the tail end 102, and several outer umbrella skirts 19 are evenly distributed on the outer wall of the front end 101.

[0038] In the above scheme, the inner umbrella skirt 18 is arranged in a 360° surround, and the outer umbrella skirt 19 is arranged in a less than or equal to 180° surround. The outer umbrella skirt 19 and the insulating tongue 12 face the same direction, and the outer umbrella skirt 19 is symmetrically centered with respect to the insulating tongue 12. The outer umbrella skirt 19 ensures that the external creepage distance of the contact box 10 meets the requirements of a neutral point non-directly grounded system and can withstand line voltage without insulation failure. Similarly, the inner umbrella skirt 18 increases the internal creepage distance of the contact box 10, meets the requirements of a neutral point non-directly grounded system, and prevents surface discharge or breakdown problems caused by the phase voltage rising to the line voltage during a single-phase short circuit.

[0039] refer to Figure 5 The busbar 20 is installed inside the insulating tongue 12. A stationary contact 16 is attached to one side of the busbar 20. A countersunk hole 17 is provided on the stationary contact 16. A threaded hole 171 that is concentrically fitted with the countersunk hole 17 is provided at the bottom of the contact box 10.

[0040] In the above scheme, a bolt is installed inside the countersunk hole 17 of the stationary contact 16. The bolt passes through the busbar 20 and enters the threaded hole 171. Tightening the bolt can stabilize the connection of the busbar 20.

[0041] Specifically, the busbar 20 and the stationary contact 16 form a high-voltage conductive circuit. The live distance from the bolt 15 to the busbar 20 in the figure cannot meet the requirements of the 17.5kV voltage level (when there is no extension tongue 121 on the insulating tongue 12). The insulating tongue 12 and the extension tongue 121 are set between the busbar 20 and the bolt 15, which increases the creepage distance and plays the role of insulation and barrier, thus significantly improving the electrical performance.

[0042] The specific implementation process of this utility model is as follows:

[0043] The principle of contact box 10: busbar 20 and stationary contact 16 form a high-voltage conductive circuit with L electrical distance. This installation method increases the creepage distance and improves electrical performance. The insulating tongue 12 and the extension tongue 121 are located between busbar 20 and bolt 15, which not only increases the creepage distance but also plays the role of insulation and barrier, thus significantly improving electrical performance.

[0044] Installation of contact box 10: Pass contact box 10 through sheet metal wall 30, and achieve initial positioning and installation by matching mounting boss 13 with the hole opened in sheet metal wall 30; pass bolt 15 through metal cover 14 into mounting screw hole 131, and tighten bolt 15 to complete the installation of contact box 10.

[0045] The above embodiments are merely exemplary models of this utility model and are not intended to limit this utility model. The scope of protection of this utility model is defined by the claims. Various modifications or equivalent substitutions can be made to this utility model within its substance and scope of protection. Such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this utility model.

[0046] In the description of this utility model, it should be noted that the terms "inner," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the attached circle, or the orientation or positional relationship commonly used when the utility model product is in use. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, these terms indicating orientation or positional relationship should not be construed as limitations on this utility model.

[0047] In the description of this utility model, it should be further noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, these terms can refer to a fixed connection, a detachable connection, or an integral connection between components; they can also refer to a mechanical connection or an electrical connection; or they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

Claims

1. An insulation reinforced contact box for 17.5 kV metal-enclosed switchgear of the draw-out type, comprising a contact box (10), a sheet metal wall (30) and a busbar (20), characterized in that: The contact box (10) has a mounting seat (11) at the bottom end, and an insulating tongue (12) at the front part, one end of the insulating tongue (12) has an extension tongue (121); The contact box (10) is connected with the metal wall (30) through the mounting seat (11).

2. An insulation reinforced contact box for 17.5 kV draw-out metal- clad switchgear according to claim 1, characterized in that: The mounting seat (11) is in a rectangular shape, mounting bosses (13) are arranged on the four corners of the mounting seat (11), the metal wall (30) is bent towards one side, the metal wall (30) is provided with holes matched with the mounting bosses (13), and one side of the mounting seat (11) provided with the mounting bosses (13) is in contact with the metal wall (30) in the bending direction.

3. An insulation reinforced contact box for 17.5 kV draw-out metal- clad switchgear according to claim 2, characterized in that: A metal cover (14) is arranged on the mounting boss (13), the mounting boss (13) is internally provided with a mounting screw hole (131), and a bolt (15) is arranged in the mounting screw hole (131).

4. An insulation reinforced contact box for 17.5 kV draw-out metal- clad switchgear according to claim 1, characterized in that: The contact box (10) is composed of a front end (101) and a tail end (102), the tail end (102) is in a cylindrical shape, and the front end (101) is provided with a taper.

5. An insulation reinforced contact box for 17.5 kV draw-out metal- clad switchgear according to claim 4, characterized in that: A plurality of inner umbrella skirts (18) are equidistantly arranged on the inner wall of the tail end (102), and a plurality of outer umbrella skirts (19) are equidistantly arranged on the outer wall of the front end (101).

6. An insulation reinforced contact box for 17.5 kV metal-enclosed switchgear of the draw-out type according to claim 5, characterized in that: The inner umbrella skirts (18) are arranged in a 360° ring, the outer umbrella skirts (19) are arranged in a ring less than or equal to 180°, the outer umbrella skirts (19) are symmetrical to the insulating tongue (12), and the outer umbrella skirts (19) are symmetrical to the insulating tongue (12).

7. An insulation reinforced contact box for 17.5 kV metal-enclosed switchgear of the draw-out type according to claim 6, characterized in that: The female busbar (20) is inserted into the insulating tongue (12) for installation, one side of the female busbar (20) is attached with a static contact (16), the static contact (16) is provided with a counterbore (17), and the inside bottom end of the contact box (10) is provided with a threaded hole (171) concentrically matched with the counterbore (17).

Images