Busbar differential protection test workbench

Abstract

The invention discloses a busbar differential protection test workbench, which relates to the technical field of test devices and specifically comprises a base plate and an upper cover plate, a microcomputer protection tester is placed in the upper cover plate, and a scissor type lifting mechanism is arranged between the base plate and the upper cover plate. The base plate and the upper cover plate can be separated for expansion or close for storage under adjustment of the scissor type lifting mechanism, side baffles are arranged outside the two sides of the base plate and the two sides of the upper cover plate, and semi-open sliding grooves are formed in the side baffles. According to the multifunctional detection platform, in the using process, flexible expansion and automatic limiting can be carried out through the arranged base plate, the upper cover plate, the first supporting rod, the second supporting rod and other structures, the detection supporting requirement is met, in the transferring process, the multifunctional detection platform can carry out storage adjustment of maximum limiting, and the practicability is high. And the occupied area is reduced, and meanwhile the flexibility in the transferring process can be fully improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of testing devices, in particular to a bus differential protection test workbench. BACKGROUND

[0002] The bus differential protection test workbench is a device for testing the function of bus differential protection, mainly including a microcomputer protection tester, a workbench, etc., wherein the microcomputer protection tester is a comprehensive test platform for power system relay protection and automation devices, which can perform setting value verification, complete set testing and action characteristic evaluation on overcurrent, overvoltage, differential, distance, zero sequence, synchronization and frequency protection, etc., and in specific use, can be used for verification and debugging of bus protection devices in the power system, testing of bus differential protection logic, simulation of bus fault scenarios, verification of action characteristics of protection devices, etc., in addition, the bus differential protection test workbench can support multiple fault types, such as simulation of phase-to-phase short circuit and ground fault, covering different grounding systems (such as neutral point high resistance grounding), and has a wide range of use.

[0003] However, with the diversification of detection environment, the use of the bus differential protection test workbench has also caused new challenges, for example, the overall hardware structure of the existing bus differential protection test workbench is large and cannot be adjusted, which is difficult to adapt to narrow working space and has great difficulty in transportation, and the flexibility of use is very poor, therefore, in view of the above problems existing in the prior art, the applicant will provide a bus differential protection test workbench to solve the problems. SUMMARY

[0004] The present application provides a bus differential protection test workbench, which solves the technical problems proposed in the background art.

[0005] In order to achieve the above purpose, the following technical scheme is adopted: a bus differential protection test workbench, comprising a base plate and an upper cover plate, a microcomputer protection tester is placed in the interior of the upper cover plate, a scissor type lifting mechanism is arranged between the base plate and the upper cover plate, and the base plate and the upper cover plate can be expanded apart or stored close under the adjustment of the scissor type lifting mechanism, side baffles are arranged on the outer sides of the base plate and the upper cover plate, and a semi-open sliding groove is formed in the interior of the side baffles, a first fastener fixed on the side of the base plate or the side of the upper cover plate is sleeved in the semi-open sliding groove, U-shaped rods are formed in the interiors of the base plate and the upper cover plate, the side baffles can be sleeved into the interiors of the U-shaped rods, and after the base plate and the upper cover plate are stored close and the side baffles are sleeved and stored in the interiors of the U-shaped rods, a U-shaped locking plate is locked and sleeved between the two first fasteners in the adjacent position.

[0006] Preferably, the scissors lifting mechanism comprises two first supporting rods, two second supporting rods, one end of the two first supporting rods is respectively hingedly installed on the front and rear ends of one side of the base plate, one end of the two first supporting rods is respectively hingedly installed on the front and rear ends of one side of the upper cover plate, the other end of the first supporting rod is slidingly installed in the front end or the rear end of the other side of the upper cover plate, the other end of the second supporting rod is slidingly installed in the front end or the rear end of the other side of the base plate, a H-shaped shaft is hingedly installed at the intersection of the second supporting rod and the first supporting rod, and the combined assembly of the first supporting rod and the second supporting rod can adjust the base plate and the upper cover plate to be close to or away from each other under the support of the H-shaped shaft after expanding or shrinking.

[0007] Preferably, a first slot and a second slot are formed in the front and rear ends of the other side of the base plate and the front and rear ends of the other side of the upper cover plate, and the second slot is in space communication with the first slot and forms a cross-shaped sliding groove, a cross-shaped shaft is sleeved in the cross-shaped sliding groove, and one end of the cross-shaped shaft is sleeved in the end of the other end of the first supporting rod or the end of the other end of the second supporting rod through a pin shaft.

[0008] Preferably, the first fastener comprises a first T-shaped screw rod and a first positioning nut, one end of the first T-shaped screw rod can penetrate through the semi-open sliding groove and be fixed to the side of the base plate or the side of the upper cover plate, and the first positioning nut is threadedly connected to the surface of the first T-shaped screw rod and can limit the position of the side baffle and the base plate or the upper cover plate by screw engagement with the first T-shaped screw rod.

[0009] Preferably, a bottom protection seat and a sealing cover are respectively installed on the top of the base plate and the bottom of the upper cover plate, a buffer pad is sleeved in the inside of the bottom protection seat, an installation groove capable of sleeving and accommodating a microcomputer protection tester and a plurality of auxiliary grooves are formed in the inside of the buffer pad, and a buffer assembly is sleeved in the inside of the sealing cover.

[0010] Preferably, the buffer assembly comprises a damping plate, a transition supporting plate and a spring, the transition supporting plate is installed between the top of the damping plate and one end of the spring, the other end of the spring is fixed to the inner wall of the top of the upper cover plate, the transition supporting plate and the damping plate are clamped in the inside of the sealing cover, and the number of springs is not less than two and is equidistantly arranged on the top of the transition supporting plate.

[0011] Preferably, guide grooves are formed in the front and rear ends of the sealing cover, U-shaped rods are slidingly installed in the guide grooves, and L-shaped rods fixed to the surface of the upper cover plate are clamped in the inside of the U-shaped rods.

[0012] Preferably, the surface of one side of the side baffle is provided with a receiving groove, a expansion plate and two reinforcing plates capable of reciprocating and receiving into the space are hingedly installed inside the receiving groove through a pin shaft, the two reinforcing plates are respectively located at the front and rear ends of the expansion plate, and a second fastener is arranged between the end of the reinforcing plate and the corresponding side surface of the expansion plate.

[0013] Preferably, the second fastener comprises a second T-shaped screw rod, a second positioning nut, a half-open combined groove is formed in the end of the reinforcing plate, one end of the second T-shaped screw rod is fixed on the corresponding side surface of the expansion plate, and the other end of the second T-shaped screw rod can be sleeved with the half-open combined groove when the expansion plate is in a horizontal state, and the second positioning nut is threadedly connected to the surface of the second T-shaped screw rod and can lock and limit the connection between the expansion plate and the reinforcing plate through the screwing with the second T-shaped screw rod.

[0014] Preferably, the surface of the rear end of the upper cover plate is fixed with a handle, and the front end surface of the upper cover plate and the front end surface of the base plate are both fixed with a roller.

[0015] The present application has the following advantages:

[0016] 1、The two first supporting rods and the two second supporting rods of the present application are arranged to cross each other to support the base plate and the upper cover plate, and the two side baffles and the plurality of first fasteners are combined to form a multifunctional detection platform, which can provide a detection support plane of different heights after the cross scissors type lifting adjustment of the first supporting rods and the second supporting rods, and the stability of the detection support plane during use can be fully guaranteed by the combined limiting of the two side baffles and the plurality of first fasteners on the base plate and the upper cover plate.

[0017] 2、The multifunctional detection platform of the present application can be flexibly expanded and automatically limited by the structures such as the base plate, the upper cover plate, the first supporting rods and the second supporting rods during use, so as to meet the detection support requirements, and the multifunctional detection platform can be maximally limited and adjusted during transfer, so as to reduce the floor area and fully improve the flexibility during transfer.

[0018] 3、The sealing cover, the bottom protection base, the buffer pad, the buffer assembly and other structures of the present application can form an auxiliary mechanism capable of sleeving and receiving a microcomputer protection tester and other small detection devices on the basis of the structure of the multifunctional detection platform, so as to integrally transfer the microcomputer protection tester and other small detection devices with the multifunctional detection platform, and further improve the operation efficiency during subsequent periodical use and the safety during the turnover movement of the microcomputer protection tester. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1A perspective view of the structure of the present application;

[0020] Figure 2 A front view of the structure of the present application;

[0021] Figure 3 A rear view of the structure of the present application;

[0022] Figure 4 A right view of the structure of the present application;

[0023] Figure 5 A perspective view of the base plate in the structure of the present application;

[0024] Figure 6 A sectional view of the sealing cover in the structure of the present application;

[0025] Figure 7 An enlarged view of A in the structure of the present application; Figure 1

[0026] An enlarged view of B in the structure of the present application; Figure 8

[0027] An enlarged view of C in the structure of the present application; Figure 9 Figure 2 A storage view of the structure of the present application;

[0028] Figure 10 An enlarged view of the storage U-shaped lock plate in the structure of the present application.

[0029] Figure 11 In the figure: 1, base plate; 2, upper cover plate; 3, first supporting rod; 4, second supporting rod; 5, side stop plate; 6, first fastener; 7, microcomputer protection tester; 8, bottom protection seat; 9, sealing cover; 10, buffer pad; 11, damping plate; 12, transition supporting plate; 13, spring; 14, L-shaped rod; 15, U-shaped rod; 16, storage groove; 17, expansion supporting plate; 18, reinforcing plate; 19, second fastener; 20, mounting groove; 21, auxiliary groove; 22, roller; 23, first slot; 24, second slot; 25, cross-shaped shaft; 26, storage U-shaped lock plate; 27, handle. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described clearly and completely below in combination with the preferred embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0031] The technical solutions of the present application will be described clearly and completely below in combination with the preferred embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application. ​

[0032] like Figures 1-7 , Figures 10-11 A differential protection test bench includes a base plate 1 and an upper cover plate 2. A microcomputer protection tester 7 is placed inside the upper cover plate 2. A scissor-type lifting mechanism is provided between the base plate 1 and the upper cover plate 2. The base plate 1 and the upper cover plate 2 can be expanded apart or retracted together under the adjustment of the scissor-type lifting mechanism. Side baffles 5 are provided on both sides of the base plate 1 and both sides of the upper cover plate 2. A semi-open slide groove is opened inside the side baffle 5. A first fastener 6 is fitted inside the semi-open slide groove and fixed on the side of the base plate 1 or the side of the upper cover plate 2. The first fastener 6 includes a first T-shaped screw and a first positioning nut. One end of the first T-shaped screw can pass through the semi-open slide groove and be fixed on the side of the base plate 1 or the side of the upper cover plate 2. The first positioning nut is threaded to the surface of the first T-shaped screw and can press and lock the side baffle 5 with the base plate 1 or the upper cover plate 2 through the helical engagement with the first T-shaped screw.

[0033] Both the base plate 1 and the upper cover plate 2 have U-shaped rods 15 inside. The side baffles 5 can be fitted into the U-shaped rods 15. When the base plate 1 and the upper cover plate 2 are in a close-packed state and the side baffles 5 are fitted into the U-shaped rods 15, a U-shaped locking plate 26 is locked between two adjacent first fasteners 6. The scissor-type lifting mechanism includes two first support rods 3 and two second support rods 4. One end of each of the two first support rods 3 is hinged to the front and rear ends of one side of the base plate 1. On the front and rear ends of one side of the upper cover plate 2, the other end of the first support rod 3 is slidably installed in the front or rear end of the other side of the upper cover plate 2, and the other end of the second support rod 4 is slidably installed in the front or rear end of the other side of the base plate 1. An I-shaped shaft is hinged at the intersection of the second support rod 4 and the first support rod 3. The combination formed by the first support rod 3 and the second support rod 4, under the support of the I-shaped shaft, can cross-expand or contract to allow the base plate 1 and the upper cover plate 2 to be adjusted to be close or far apart, thereby meeting the usage requirements of different heights in the subsequent actual environment.

[0034] A first strip groove 23 and a second strip groove 24 are provided in the front and rear ends of the other side of the base plate 1 and the front and rear ends of the other side of the top cover plate 2. The second strip groove 24 is spatially connected with the first strip groove 23 and forms a cross-shaped slide groove. A cross-shaped shaft 25 is fitted inside the cross-shaped slide groove. One end of the cross-shaped shaft 25 is fitted into the end of the other end of the first support rod 3 or the other end of the second support rod 4 through a pin. Thus, the cross-shaped shaft 25 and the cross-shaped slide groove are reciprocated to further improve the stability of the combination formed by the first support rod 3 and the second support rod 4 in adjusting the height of the base plate 1 and the top cover plate 2.

[0035] When in use, when forming a testing platform in the environment to be tested, place it in the overall device, with the base plate 1 as the bottom support, pull out the side baffle 5 inside the base plate 1 and the side baffle 5 inside the top cover plate 2, and when the side baffle 5 is fitted into the U-shaped rod 15 inside the base plate 1 or the U-shaped rod 15 inside the top cover plate 2, part of the structure protrudes to the outside of the base plate 1 or the outside of the top cover plate 2. Tighten the first positioning nuts inside the multiple first fasteners 6 in sequence, and temporarily move the first positioning nuts away from the base plate 1 or the top cover plate 2. After completion, take out the storage U-shaped locking plate 26 that was originally fitted outside the first T-shaped screw.

[0036] Next, pull the upper cover plate 2 to move it upward toward the top of the base plate 1 until it reaches a suitable height. During the movement of the upper cover plate 2, the first support rod 3 and the second support rod 4 will slide and move out of position simultaneously. After the upper cover plate 2 is adjusted, the semi-open sliding groove inside the side baffle 5 is fitted and engaged one by one with the first T-shaped screw on one side of the base plate 1 and the first T-shaped screw on one side of the upper cover plate 2 until the bottom surface of the side baffle 5 and the bottom surface of the base plate 1 are in a coplanar position. Then, the first positioning nuts inside the multiple first fasteners 6 are reset in sequence. In this way, the two side baffles 5 are used to strengthen and position the adjusted base plate 1 and upper cover plate 2. The upper cover plate 2 then provides a stable and spacious testing platform for subsequent testing operations and the microcomputer protection tester 7.

[0037] like Figures 1-11 The bottom protective seat 8 and the bottom of the top cover plate 2 are respectively installed on the top of the base plate 1 and the bottom of the top cover plate 2. The bottom protective seat 8 is fitted with a buffer pad 10. The buffer pad 10 has an installation slot 20 for housing the microcomputer protection tester 7 and several auxiliary slots 21. The sealing cover 9 is fitted with a buffer assembly, which includes a damping plate 11, a transition support plate 12 and a spring 13 fitted inside the sealing cover 9. The transition support plate 12 is installed between the top of the damping plate 11 and one end of the spring 13. The other end of the spring 13 is fixed to the inner wall of the top of the top cover plate 2. The transition support plate 12 and the damping plate 11 are both snapped into the inside of the sealing cover 9. There are no less than two springs 13, which are equidistantly arranged on the top of the transition support plate 12.

[0038] The sealing cover 9 has guide grooves at both the front and rear ends. A U-shaped rod 15 is slidably installed in the guide groove. An L-shaped rod 14 fixed to the surface of the upper cover plate 2 is snapped into the inside of the U-shaped rod 15. The snapping of the U-shaped rod 15 and the L-shaped rod 14 guides and constrains the displacement of the transition support plate 12 and the damping plate 11 inside the sealing cover 9. A handle 27 is fixed to the rear end surface of the upper cover plate 2. Rollers 22 are fixed to the front end surface of the upper cover plate 2 and the front end surface of the base plate 1.

[0039] When in use, considering the need for integrated storage of the microcomputer protection tester 7 with the base plate 1, the top cover plate 2, etc., after the testing operation is completed, the microcomputer protection tester 7 can be stored in the mounting slot 20, while other small testing devices or tools can be stored in the multiple auxiliary slots 21. After completion, the first positioning nuts inside the multiple first fasteners 6 are turned in sequence, and the first positioning nuts are temporarily moved away from the base plate 1 or the top cover plate 2. Then, the two side baffles 5 are pulled out from the outside of the assembly formed by the base plate 1 and the top cover plate 2, and the support of the base plate 1 and the top cover plate 2 is released.

[0040] Press the top cover plate 2 to move it toward the top of the base plate 1 until the bottom surface of the sealing cover 9 is in contact with the top surface of the bottom protective seat 8. During the assembly of the bottom protective seat 8 and the sealing cover 9, the damping plate 11 and the transition support plate 12 inside the sealing cover 9 will press against the top of the microcomputer protection tester 7 and move it to make way for the inside of the sealing cover 9. In the subsequent centralized transfer process of the microcomputer protection tester 7 with the base plate 1, the top cover plate 2 and other structures, the damping plate 11 will link the transition support plate 12 and multiple springs 13 to provide damping and buffering, so as to fully ensure the stability and safety of the microcomputer protection tester 7 and other small testing devices during the transfer process.

[0041] After the microcomputer protection tester 7 and other small testing devices are stored, the two side baffles 5 are respectively snapped into the U-shaped rod 15 inside the base plate 1 and the U-shaped rod 15 inside the top cover plate 2. Then, the storage U-shaped locking plate 26 is fitted with the two adjacent first T-shaped screws. After that, the corresponding first positioning nuts are reset and locked. In this way, the base plate 1 and the top cover plate 2 in the storage state can be limited and locked to ensure the reliability and flexibility of the subsequent overall device transportation.

[0042] like Figures 1-7 A storage groove 16 is provided on one side of the side baffle 5. An extension support plate 17 and two reinforcing plates 18 are installed inside the storage groove 16 by means of a pin hinge. The two reinforcing plates 18 are located at the front and rear ends of one side of the extension support plate 17, and a second fastener 19 is provided between one end of the reinforcing plate 18 and the corresponding side of the extension support plate 17.

[0043] The second fastener 19 includes a second T-shaped screw and a second positioning nut. A semi-open combination groove is provided in the end of one end of the reinforcing plate 18. One end of the second T-shaped screw is fixed to the corresponding side of the extension support plate 17, and the other end of the second T-shaped screw can be fitted into the semi-open combination groove after the extension support plate 17 is in a horizontal state. The second positioning nut is threaded to the surface of the second T-shaped screw and can lock and limit the connection between the extension support plate 17 and the reinforcing plate 18 by spiral locking with the second T-shaped screw.

[0044] In actual testing, considering the issue of insufficient testing platform area, adjustments can be made using structures such as the extended support plate 17 and the reinforcing plate 18. The specific operation is as follows:

[0045] Flip the extension support plate 17 until it is parallel to the upper cover plate 2. Then, screw the second positioning nuts inside the two second fasteners 19 on the outside of the extension support plate 17 away from the extension support plate 17. After that, flip the two reinforcing plates 18 located outside the extension support plate 17 until the semi-open combination groove inside the reinforcing plate 18 is connected to the second T-shaped screw. After that, reset and screw the second positioning nuts to lock and limit the connection between the extension support plate 17 and the reinforcing plate 18 by spiral locking with the second T-shaped screw. In this way, the top surface of the extension support plate 17 is used as the extension surface of the upper cover plate 2 to meet the detection support requirements of a larger support area.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention. The invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A differential protection test bench, comprising a base plate (1) and an upper cover plate (2), wherein a microcomputer protection tester (7) is placed inside the upper cover plate (2), characterized in that: A scissor-type lifting mechanism is provided between the base plate (1) and the upper cover plate (2), and the base plate (1) and the upper cover plate (2) can be expanded apart or retracted together under the adjustment of the scissor-type lifting mechanism. Side baffles (5) are provided on both sides of the base plate (1) and both sides of the upper cover plate (2), and a semi-open sliding groove is provided inside the side baffle (5). A first fastener (6) fixed on the side of the base plate (1) or the side of the upper cover plate (2) is fitted in the semi-open sliding groove. A U-shaped rod (15) is provided inside the base plate (1) and the upper cover plate (2). The side baffle (5) can be fitted into the U-shaped rod (15). When the base plate (1) and the upper cover plate (2) are in a retracted state and the side baffle (5) is fitted into the U-shaped rod (15), a U-shaped locking plate (26) is locked between the two first fasteners (6) in adjacent positions.

2. The bus differential protection test bench according to claim 1, characterized in that: The scissor-type lifting mechanism includes two first support rods (3) and two second support rods (4). One end of each of the two first support rods (3) is hinged to the front and rear ends of one side of the base plate (1). The other end of each of the two first support rods (3) is hinged to the front and rear ends of one side of the upper cover plate (2). The other end of each of the first support rods (3) is slidably installed in the front or rear end of the other side of the upper cover plate (2). The other end of each of the second support rods (4) is slidably installed in the front or rear end of the other side of the base plate (1). An I-shaped shaft is hinged at the intersection of the second support rod (4) and the first support rod (3). The combination formed by the first support rod (3) and the second support rod (4) can be adjusted to be close to or far apart by the base plate (1) and the upper cover plate (2) after being cross-expanded or contracted under the support of the I-shaped shaft.

3. The bus differential protection test bench according to claim 1, characterized in that: The front and rear ends of the base plate (1) and the front and rear ends of the top cover plate (2) are provided with a first strip groove (23) and a second strip groove (24). The second strip groove (24) is spatially connected with the first strip groove (23) and forms a cross-shaped slide groove. A cross-shaped shaft (25) is fitted inside the cross-shaped slide groove. One end of the cross-shaped shaft (25) is fitted into the end of the first support rod (3) or the end of the second support rod (4) through a pin.

4. The bus differential protection test bench according to claim 1, characterized in that: The first fastener (6) includes a first T-shaped screw and a first positioning nut. One end of the first T-shaped screw can pass through a semi-open groove and be fixed to the side of the base plate (1) or the side of the top cover plate (2). The first positioning nut is threaded to the surface of the first T-shaped screw and can be used to press and lock the side baffle (5) against the base plate (1) or the top cover plate (2) by engaging with the first T-shaped screw.

5. The bus differential protection test bench according to claim 1, characterized in that: The bottom of the base plate (1) and the bottom of the top cover plate (2) are respectively equipped with a bottom protection seat (8) and a sealing cover (9). The bottom protection seat (8) is fitted with a buffer pad (10). The buffer pad (10) has an installation slot (20) and several auxiliary slots (21) inside, which can accommodate the microcomputer protection tester (7). The sealing cover (9) is fitted with a buffer component.

6. The bus differential protection test bench according to claim 5, characterized in that: The buffer assembly includes a damping plate (11), a transition support plate (12), and a spring (13) fitted inside the sealing cover (9). The transition support plate (12) is installed between the top of the damping plate (11) and one end of the spring (13). The other end of the spring (13) is fixed to the inner wall of the top of the upper cover plate (2). The transition support plate (12) and the damping plate (11) are both snapped into the inside of the sealing cover (9). There are no fewer than two springs (13) and they are arranged at equal intervals on the top of the transition support plate (12).

7. The bus differential protection test bench according to claim 5, characterized in that: The sealing cover (9) has guide grooves at both the front and rear ends. A U-shaped rod (15) is slidably installed in the guide groove. An L-shaped rod (14) fixed to the surface of the upper cover plate (2) is snapped into the inside of the U-shaped rod (15).

8. The bus differential protection test bench according to claim 1, characterized in that: A storage groove (16) is provided on one side of the side baffle (5). An extension support plate (17) and two reinforcing plates (18) that can be reciprocated into their own space are installed inside the storage groove (16) by a pin hinge. The two reinforcing plates (18) are located at the front and rear ends of one side of the extension support plate (17), and a second fastener (19) is provided between one end of the reinforcing plate (18) and the corresponding side of the extension support plate (17).

9. The bus differential protection test bench according to claim 8, characterized in that: The second fastener (19) includes a second T-shaped screw and a second positioning nut. A semi-open combination groove is provided in the end of one end of the reinforcing plate (18). One end of the second T-shaped screw is fixed on the corresponding side of the extension support plate (17), and the other end of the second T-shaped screw can be fitted into the semi-open combination groove after the extension support plate (17) is in a horizontal state. The second positioning nut is threaded to the surface of the second T-shaped screw and can lock and limit the connection between the extension support plate (17) and the reinforcing plate (18) by spiral locking with the second T-shaped screw.

10. A bus differential protection test bench according to claim 1, characterized in that: A handle (27) is fixed to the rear surface of the upper cover plate (2), and rollers (22) are fixed to the front surface of the upper cover plate (2) and the front surface of the base plate (1).

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