Loop resistance auxiliary test wire clamp and method

Abstract

The invention discloses a loop resistance auxiliary test wire clamp and method, and relates to the technical field of electric power engineering, the loop resistance auxiliary test wire clamp comprises a clamp head, a clamping piece, a limiting block and a connecting piece, the clamping piece is arranged on the outer wall of the clamping piece, the limiting block is arranged on the outer wall of the clamping piece, and the connecting piece is arranged on the outer wall of the clamping piece; the clamping piece can extend into the tulip contact; by arranging the chuck structure, the current lead and the voltage lead are integrated on the same clamping piece, and the clamping pieces can extend into the tulip contact to realize uniform surface contact, so that the contact area is remarkably increased, the contact resistance is reduced, and the accuracy and repeatability of loop resistance testing are improved; mechanical damage to the plum blossom contact caused by point contact or too large clamping force of a traditional wire clamp is effectively avoided; and meanwhile, two independent current clamps and voltage clamps required by each contact originally are combined into one, so that the number and weight of test wires are greatly reduced, the wiring operation is simplified, the skill requirements on testers are reduced, and the field test efficiency and safety are improved.

Description

Technical Field

[0001] This invention relates to the field of power engineering technology, and in particular to an auxiliary test clamp and method for loop resistance. Background Technology

[0002] In power system operation and maintenance, vacuum circuit breakers, as critical switching equipment, directly impact the safe and stable operation of the power grid due to the health of their conductive circuits. Circuit resistance testing is a crucial method for evaluating the contact performance and conductivity of vacuum circuit breaker contacts. A four-wire method is typically used, connecting two current wires and two voltage wires to the moving and stationary L-shaped contacts at the circuit breaker terminals, respectively. Therefore, a dedicated test clamp is required during testing to ensure a reliable electrical connection with the L-shaped contacts, guaranteeing the accuracy and repeatability of the test data.

[0003] However, existing test clamps have many shortcomings in practical applications: First, traditional clamps mostly adopt point contact or clamping structures, resulting in a small contact area with the inner wall of the L-shaped contact and uneven pressure distribution, which easily causes local stress concentration, leading to mechanical damage to the contact and even affecting the life of the equipment; Second, poor contact can introduce additional contact resistance, causing the measured loop resistance value to be too high, resulting in misjudgment; Third, the test requires the use of four independent wires at the same time, resulting in numerous and heavy cables, which not only increases the burden on the test personnel but also increases the complexity of wiring and the risk of operational errors; Fourth, although some improved devices attempt to increase the contact area or achieve size adjustment, the structure is split and requires on-site assembly, and the current and voltage channels are not integrated into one unit, so the compatibility and convenience are still insufficient; These factors seriously restrict the accuracy, safety, and efficiency of loop resistance testing.

[0004] Based on the above problems, we propose a loop resistance auxiliary test clamp and method. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is: how to solve the problems of small contact area, easy damage to the Phillips head contacts, numerous test lines, complicated operation and low test accuracy of existing test clamps.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a loop resistance auxiliary test clamp, which includes a clamping head, a clamping member, a clamping piece disposed on the outer wall of the clamping member, a limiting block disposed on the outer wall of the clamping member, and a connecting member disposed on the outer wall of the clamping member; the clamping piece can extend into the interior of the plum blossom contact; an insulating handle is connected to the outer wall of the clamping head.

[0007] In a preferred embodiment of the circuit resistance auxiliary test clamp of the present invention: the clamping member includes a first clamping block and a second clamping block that are movably connected, and the clamping pieces are provided on the outer walls of both the first clamping block and the second clamping block.

[0008] In a preferred embodiment of the circuit resistance auxiliary test clamp of the present invention: the connector includes a first connection position provided on the outer wall of the first clamp block, and the outer wall of the second clamp block is provided with a second connection position.

[0009] In a preferred embodiment of the loop resistance auxiliary test clamp of the present invention: the outer wall of the first connection position is provided with a current conductor, and the outer wall of the second connection position is provided with a voltage conductor.

[0010] In a preferred embodiment of the circuit resistance auxiliary test clamp of the present invention: the insulating grip includes a first handle connected to the first clamping block, and the second clamping block is connected to the outer wall with a second handle.

[0011] In a preferred embodiment of the circuit resistance auxiliary test clamp of the present invention: an elastic element is provided between the first handle and the second handle.

[0012] In a preferred embodiment of the circuit resistance auxiliary test clamp of the present invention: a limiting frame is provided through the outer wall of the first handle, and a plurality of limiting grooves are provided on the outer wall of the insulating grip, wherein the limiting frame and the limiting grooves are movably engaged.

[0013] The present invention also proposes an auxiliary test method for loop resistance, which includes inserting a clamp into the inside of the pentagonal contact of the device under test, and clamping the pentagonal contact by operating an insulating grip to establish an electrical connection. A test current is passed through a current conductor, and a voltage signal is simultaneously acquired through a voltage conductor to calculate the loop resistance value.

[0014] In a preferred embodiment of the circuit resistance auxiliary testing method of the present invention: during the clamping process of the plum blossom contact, the clamping stroke is adjusted by the cooperation of the limiting frame and the limiting groove to ensure that the clamping piece and the plum blossom contact are in stable contact and do not damage the contact surface.

[0015] In a preferred embodiment of the circuit resistance auxiliary testing method of the present invention: after the test is completed, grip the insulating handle tightly to disengage the clip from the inner wall of the plum blossom contact.

[0016] The beneficial effects of this invention are as follows: By setting a clamp structure, the current conductor and voltage conductor are integrated on the same clamping component, and the clamping plates can extend into the interior of the Phillips-shaped contact to achieve uniform surface contact. This not only significantly increases the contact area and reduces the contact resistance, improving the accuracy and repeatability of the loop resistance test, but also effectively avoids mechanical damage to the Phillips-shaped contact caused by point contact or excessive clamping force in traditional clamps. At the same time, the two separate current clamps and voltage clamps required for each contact are combined into one, greatly reducing the number and weight of test leads, simplifying wiring operations, reducing the skill requirements for test personnel, and improving on-site testing efficiency and safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 A schematic diagram of the connection structure between the test clamp and the Phillips head contact is shown. Figure 2 A schematic diagram of the clamp connection structure is shown; Figure 3 A schematic diagram of the overall connection structure of the test clamp is shown; Figure 4 A schematic diagram of the connection structure between the clamp and the insulated grip is shown. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0020] Reference Figures 1-4 This embodiment provides a loop resistance auxiliary test clamp, including a clamp 1 and a clamping member 11. The clamping member 11 automatically expands after being inserted into the L-shaped contact M, causing the clamping piece 12 to fit against the inner wall of the contact. The clamping piece 12, preferably arc-shaped, is located on the outer wall of the clamping member 11. Its surface is treated with conductive material, providing good conductivity and wear resistance. During clamping, the clamping piece 12 expands outwards, extending into the L-shaped contact M and forming a large-area contact with the inner wall, rather than traditional point contact or edge clamping. This avoids plastic deformation or scratches to the L-shaped contact due to stress concentration, achieving non-destructive testing. The limiting block 13 on the outer wall of the clamping member 11 prevents excessive force when the front end of the clamp 1 is tightened, thus acting as a barrier to prevent mechanical damage. The connector 14 on the outer wall of the clamping member 11 is used to lead out the current wire 143 and the voltage wire 144 respectively. By integrating the current and voltage channels into the same clamp 1, the two clamps 1 can be clamped at the moving and stationary sprite contacts respectively to complete the circuit resistance test. The clamping piece 12 can extend into the sprite contact M. The outer wall of the clamp 1 is connected to an insulated handle 2 for easy operation by the operator.

[0021] In one embodiment provided in this application, the clamping member 11 includes a first clamping block 111 and a second clamping block 112 that are movably connected. The first clamping block 111 and the second clamping block 112 achieve relative opening and closing movements through a hinge shaft. The outer walls of the first clamping block 111 and the second clamping block 112 are both fixedly provided with clamping pieces 12. In the initial state, the first clamping block 111 and the second clamping block 112 are kept in a closed state. When the operator holds the insulating handle 2 and inserts the clamp 1 into the plum blossom contact M of the vacuum circuit breaker, and then releases the grip, the elastic member 23 releases the stored energy, pushing the first clamping block 111 and the second clamping block 112 to expand outward, causing the clamping pieces 12 on their outer walls to open synchronously, closely fitting the inner wall contour of the plum blossom contact M, and can be applied to plum blossom contacts M of different diameters.

[0022] In one embodiment provided in this application, the connector 14 includes a first connection position 141 disposed on the outer wall of the first clamping block 111, and a second connection position 142 disposed on the outer wall of the second clamping block 112; the first connection position 141 and the second connection position 142 are physically disposed on the first clamping block 111 and the second clamping block 112 respectively, and are electrically isolated from each other to avoid signal crosstalk and ensure test accuracy.

[0023] In one embodiment provided in this application, the outer wall of the first connection position 141 is provided with a current conductor 143, which is used to pass current to the plum blossom contact M of the vacuum circuit breaker; the outer wall of the second connection position 142 is provided with a voltage conductor 144, which is used to collect the small voltage drop between the clamp 12 and the contact point of the plum blossom contact M. The current conductor 143 and the voltage conductor 144 are respectively connected to the current terminal and voltage terminal of the loop resistance tester. Since the first connection position 141 and the second connection position 142 are respectively set on the first clamp 111 and the second clamp 112 that can be opened and closed relative to each other, and are synchronously attached to the inner wall of the plum blossom contact M with the clamp 12, the current path and the voltage sampling path are directly established inside the effective contact area, which shortens the lead length to the maximum extent and avoids the additional resistance interference caused by the lead length and contact point offset of the traditional external clamp, which can significantly improve the test accuracy.

[0024] In one embodiment provided in this application, the insulating grip 2 includes a first handle 21 connected to the first clamping block 111, and a second handle 22 connected to the outer wall of the second clamping block 112. The first handle 21 and the second handle 22 adopt a symmetrical double-arm handle design and are made of high-strength insulating material to meet the insulation protection requirements of voltage levels of 10 kV and above. When the operator grips the insulating grip 2, the first clamping block 111 and the second clamping block 112 are pulled inward by mechanical transmission, and the clamping plate 12 retracts accordingly, making it easy to insert the clamp 1 into the interior of the vacuum circuit breaker's plum blossom contact M. After the handle is released, under the restoring force of the elastic element 23, the first clamping block 111 and the second clamping block 112 automatically open outward, causing the clamping plate 12 to tightly adhere to the inner wall of the plum blossom contact M, thereby achieving a reliable electrical connection.

[0025] In one embodiment provided in this application, an elastic element 23 is provided between the first handle 21 and the second handle 22; the elastic element 23 is preferably a torsion spring, one end of which is fixedly connected to the inside of the first handle 21 and the other end of which is fixedly connected to the inside of the second handle 22, for automatically providing an outward restoring force after the clamp 1 is inserted into the plum blossom contact M of the vacuum circuit breaker.

[0026] In one embodiment provided in this application, a limiting frame 24 is provided through the outer wall of the first handle 21. The limiting frame 24 is movably connected to the first handle 21. A plurality of limiting grooves 25 are provided on the outer wall of the insulating grip 2. The limiting frame 24 and the limiting grooves 25 are movably engaged to precisely control the expansion range of the clamp 1, thereby adapting to the different inner diameters of the sprite contacts. When the operator grips or releases the insulating grip 2, the limiting frame 24 can be adjusted to be embedded in the limiting grooves 25 at different positions. Each limiting groove 25 corresponds to a preset opening diameter of the clamping piece 12. By selecting different groove positions, the end point of the clamping stroke can be manually set to prevent the clamping piece 12 from over-expanding and causing deformation of the sprite contact M or damage to its own structure.

[0027] In use, each phase of the vacuum circuit breaker has two plum blossom contacts M, and the two test clamps can form a complete circuit. By gripping the first handle 21 and the second handle 22 of the insulating handle 2 with one hand, the elastic element 23 is compressed, causing the first clamp block 111 and the second clamp block 112 to retract inward, and the clamp plate 12 shrinks to its minimum outer diameter. Then, the clamp 1 is smoothly inserted into the plum blossom contact M. After reaching the predetermined position, the handle is released. Under the restoring force of the elastic element 23, the clamp plate 12 automatically expands outward. At this time, according to the inner diameter of the plum blossom contact M of the vacuum circuit breaker under test, the appropriate limiting groove 25 is selected. Place the clamp 1 and align the limiting frame 24 with the slot to fix the expansion of the clamp 1. The clamp 12 should fit tightly against the inner wall of the plum blossom contact M to form a uniform and stable surface contact. At this time, the current wire 143 on the first connection position 141 and the voltage wire 144 on the second connection position 142 are respectively connected to the current terminal and voltage terminal of the loop resistance tester. Repeat the above steps to install the second clamp onto another plum blossom contact M to perform a four-wire loop resistance test. After the test is completed, squeeze the handle again to quickly release the clamp 1, realizing a non-destructive, efficient and accurate full-process test operation.

[0028] Reference Figures 1-4 This embodiment provides a loop resistance auxiliary test method, which includes inserting the clamp 12 into the plum blossom contact M of the device under test, and clamping the plum blossom contact M by operating the insulating grip 2 to establish an electrical connection; Insert the clamps into the upper and lower plum blossom contacts M of the same phase of the vacuum circuit breaker respectively; by operating the insulating grips 2 of each clamp, the clamping member 11 drives the clamping plate 12 to expand outward and tightly fit the inner wall of the plum blossom contact M, thereby establishing a stable and low-resistance electrical connection at the upper and lower contacts simultaneously. A test current is passed through the current wire 143, and a voltage signal is simultaneously acquired through the voltage wire 144 to calculate the loop resistance value. Test current is supplied to the circuit through the current wire 143 on the first connection position 141, and voltage signal is collected inside the contact point through the voltage wire 144 on the second connection position 142. The accurate resistance value of the conductive circuit of this phase is calculated using the four-wire principle.

[0029] In one embodiment provided in this application, during the clamping process of the plum blossom contact M, the clamping stroke is adjusted by the cooperation of the limiting frame 24 and the limiting groove 25 to ensure that the clamping piece 12 and the plum blossom contact M are in stable contact without damaging the contact surface; During the clamping process of the plum blossom contact M, the expansion stroke of the clamping member 11 can be precisely adjusted by the cooperation between the limiting frame 24 and the multiple limiting grooves 25 provided on the outer wall of the insulating handle 2. The operator can insert the limiting frame 24 into the corresponding limiting groove 25 according to the inner diameter of the plum blossom contact to be tested, thereby limiting the maximum opening diameter of the clamping piece 12. This ensures that the clamping piece 12 can form a stable and uniform surface contact when it is in contact with the inner wall of the plum blossom contact, ensuring a good electrical connection, and effectively avoiding mechanical damage such as scratches and deformation of the contact surface caused by excessive expansion or excessive clamping force.

[0030] In one embodiment provided in this application, after the test is completed, the insulating handle 2 is gripped tightly to disengage the clip 12 from the inner wall of the plum blossom contact M; After the test is completed, grip the insulating handle 2 tightly. The opposing movement of the first handle 21 and the second handle 22 compresses the elastic element 23, causing the first clamping block 111 and the second clamping block 112 to retract inward. This causes the clamping piece 12 to retract synchronously and detach from the inner wall of the plum blossom contact M, achieving quick and non-destructive disassembly. This not only avoids contact scratches or wire clamp jamming caused by forced pulling, but also significantly improves testing efficiency. It is especially suitable for on-site batch testing scenarios that require frequent disassembly and assembly.

[0031] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A loop resistance auxiliary test clamp, characterized in that: include, The chuck (1) includes a clamping member (11), a clamping piece (12) disposed on the outer wall of the clamping member (11), a limiting block (13) disposed on the outer wall of the clamping member (11), and a connecting member (14) disposed on the outer wall of the clamping member (11). The clip (12) can extend into the interior of the plum blossom contact (M); An insulated grip (2) is connected to the outer wall of the clamp (1).

2. The loop resistance auxiliary test clamp according to claim 1, characterized in that: The clamping member (11) includes a first clamping block (111) and a second clamping block (112) that are movably connected, and the clamping pieces (12) are provided on the outer walls of the first clamping block (111) and the second clamping block (112).

3. The loop resistance auxiliary test clamp according to claim 2, characterized in that: The connector (14) includes a first connection position (141) on the outer wall of the first clamping block (111), and a second connection position (142) on the outer wall of the second clamping block (112).

4. The loop resistance auxiliary test clamp according to claim 3, characterized in that: The outer wall of the first connection position (141) is provided with a current conductor (143), and the outer wall of the second connection position (142) is provided with a voltage conductor (144).

5. The loop resistance auxiliary test clamp according to claim 4, characterized in that: The insulated grip (2) includes a first handle (21) connected to a first clamp (111), and a second handle (22) connected to the outer wall of the second clamp (112).

6. The loop resistance auxiliary test clamp according to claim 5, characterized in that: An elastic element (23) is provided between the first handle (21) and the second handle (22).

7. The loop resistance auxiliary test clamp according to claim 6, characterized in that: The outer wall of the first handle (21) is provided with a limiting frame (24), and the outer wall of the insulating grip (2) is provided with a plurality of limiting grooves (25), and the limiting frame (24) and the limiting grooves (25) are movably engaged.

8. A method for auxiliary testing of loop resistance, characterized in that: Including the loop resistance auxiliary test clamp as described in any one of claims 1 to 7, and further comprising: Insert the clamping piece into the plum blossom contact of the device under test, and clamp the plum blossom contact by operating the insulating grip to establish an electrical connection. A test current is passed through a current conductor, and a voltage signal is simultaneously acquired through a voltage conductor to calculate the loop resistance value.

9. The loop resistance auxiliary testing method according to claim 8, characterized in that: During the clamping process of the plum blossom contact, the clamping stroke is adjusted by the cooperation of the limiting frame and the limiting groove to ensure stable contact between the clamping plate and the plum blossom contact without damaging the contact surface.

10. The loop resistance auxiliary testing method according to claim 9, characterized in that: After the test is completed, grip the insulating handle tightly to disengage the clip from the inner wall of the plum blossom contact.

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