CN103344792B - Guiding structure under special end shield monitored by a kind of bushing shell for transformer - Google Patents

Abstract

A bottom-guiding structure for the end screen dedicated to transformer bushing monitoring, including an end screen shell, an insulating baffle, and an end screen guide rod; it is characterized in that it also includes: front and rear end covers; The front part of the end cover is threadedly connected with the rear part of the front end cover, and the front and rear end covers are connected to form an integral protective chamber; the lead-out and fixing device includes lead-out guide rods, crimping nuts, and insulating bushings; the polished rod section at the front of the lead-out guide rods There is a first blind hole and a built-in spring; the gap between the guide rod of the last screen is inserted in the first blind hole and is in contact with the spring; There are four through holes in the radial direction; the crimping nut is assembled on the threaded section; the insulating bushing is assembled on the threaded section; the metal bellows soft connection assembly; the pipe hard connection piece; the second metal bellows; , Rear sealing plate. It can effectively protect the lead wires to ensure good grounding of the end screen, reliable insulation, sealing, and durability to ensure its safe operation.

Description

A special end screen down-guiding structure for transformer bushing monitoring

technical field

The invention relates to the technical field of transformers, in particular to the lead-out structure of the transformer end screen.

Background technique

With the continuous development of the power grid and the continuous expansion of the scale of the power grid, it is imperative to implement the condition-based maintenance of power grid equipment. The correct collection of equipment status detection information is the basis of condition-based maintenance, which can evaluate equipment health status and fault development trends, reasonably reduce maintenance costs, improve maintenance efficiency, and ensure reliable operation of equipment. As one of the important components of the transformer, the transformer bushing is one of the extremely important equipment to ensure the safe operation of the power grid. It is particularly important to monitor its status in time. It is of great significance to timely discover potential safety hazards in the power grid and ensure the safe operation of the power grid.

None of the transformer bushings that have been installed at present can meet the test conditions for state detection without power failure, and all need to be tested under power failure conditions. There are many shortcomings such as long detection period and test data cannot accurately reflect the actual situation. Hence the need to retrofit the existing structure. Invented a special end screen lead-out structure for transformer bushing monitoring, which enables testers to safely, accurately and quickly complete the detection of the state of the transformer bushing without power failure, and at the same time ensures that the end screen is well grounded, reliable insulated, and sealed , durable to ensure its safe operation.

Contents of the invention

In order to overcome the above-mentioned shortcomings in the prior art, the object of the present invention is to provide a special end-screen down-leading structure for transformer bushing monitoring, which can safely, accurately and quickly complete the monitoring of the status of the transformer bushing without power failure. At the same time, ensure that the end screen is well grounded, and the insulation is reliable, sealed, and durable to ensure its safe operation.

In order to solve the above-mentioned problems, the present invention adopts the following technical solutions: a special end-shield down-guided structure for transformer bushing monitoring, including an end-shield shell, an insulating baffle, and an end-shield guide rod; the feature is that the end-shield guide rod Axis is the datum axis; also includes:

The front end cover is provided with a central cavity; the inner diameter of the front part on the front end cover is smaller than the inner diameter of the rear part, and a radial inner plane step is formed at the change of the inner diameter at the junction of the front part and the rear part; the front part of the front end cover The outer diameter is also smaller than the outer diameter of the rear part, and a radial outer plane step is formed at the change of the outer diameter at the junction of the front part and the rear part; the front part of the front end cover is provided with external threads and is connected to the last screen shell by threads Inside, the axis of the central cavity coincides with the reference axis; the rear part of the front end cover is provided with internal threads;

The rear end cover is also provided with a central cavity; the inner diameter of the front part of the rear end cover is larger than the inner diameter of the rear part, and a radial inner plane step is formed at the junction of the front part and the rear part where the inner diameter changes; the rear end cover The outer diameter of the upper front part is larger than that of the rear part, and a radial outer plane step is formed at the outer diameter change at the junction of the front part and the rear part; the front part of the rear end cover is connected with the rear part of the front end cover through external threads The internal thread connection, the central cavity of the front end cover and the central cavity of the rear end cover are coaxially connected to form an integral protective cavity; the rear part of the rear end cover is provided with external threads;

The lead-out and fixing device includes a lead-out guide rod, a crimping nut, and an insulating bushing; the lead-out guide rod is composed of a polished rod segment at the front and a threaded segment at the rear, and a first blind hole is set in the polished rod segment, and the first The axis of the blind hole coincides with the reference axis; the rear end of the first blind hole is equipped with a spring that expands and contracts along the direction of the reference axis; The rear end surface of the screen guide rod is in close contact with the spring; the threaded section at the rear of the lead-out guide rod is provided with external threads; a second blind hole is arranged in the threaded section, and the axis of the second blind hole is in line with the reference The axes are coincident, and the front end of the second blind hole is provided with four through holes in the radial direction; the crimping nut is assembled on the threaded section; the insulating bushing is provided with an internal threaded hole, and is also assembled on the On the threaded section; the outer diameter of the front part of the insulating bushing is greater than the inner diameter of the rear part of the rear end cover, and the outer diameter of the rear part of the insulating bushing is smaller than the inner diameter of the rear part of the rear end cover; the front part and the rear part of the insulating bushing are at the junction A radial outer plane step is formed at the change of the outer diameter of the outer diameter, and the outer plane step of the insulating bush cooperates with the inner plane step of the rear end cover to form a limiting structure;

The metal bellows soft connection assembly includes a first metal bellows and two connectors respectively arranged at both ends of the first metal bellows. The two connectors are respectively denoted as a front connector and a rear connector; body and a rear sealing plate, the rear sealing plate is tightly connected to the rear end of the cylinder body, and the cylinder body is provided with internal threads; the rear sealing plate is provided with a through hole along the reference axis; the first metal bellows The two ends of the two connectors pass through the through holes of the two connectors respectively and extend radially outward in the cylinder to form a limiting boss, the diameter of the limiting boss is larger than the diameter of the through hole; the front The internal thread of the barrel of the connector is matched with the external thread at the rear of the rear end cover;

The pipe hard connector is provided with a central cavity, and the axis of the central cavity coincides with the reference axis; the pipeline hard connector includes a first external thread section at the front, a boss section at the middle and a rear connection at the rear section; the outer diameter of the boss section is greater than the outer diameter of the first external thread section and the rear connection section; the first external thread section is threaded with the rear connector in the metal bellows soft connection assembly; the rear connection section is in An annular groove is arranged on the periphery of the central cavity, the axis of the annular groove coincides with the reference axis, the opening of the annular groove faces backward, and the inner ring wall is provided with spiral patterns that match the spiral corrugations of the metal bellows.

The second metal bellows, on the inner wall of the front end of the second metal bellows, tighten the inner ring wall of the annular clamping groove of the pipeline hard connector;

The end head is connected to the rear end of the cylinder by the cylinder body, the rear sealing plate, and the rear sealing plate. The cylinder body is provided with an internal helix that matches the spiral corrugation of the second metal bellows; and through the internal helix It is screwed on the outer wall of the rear end of the second metal bellows, and the rear sealing plate is provided with a through hole along the reference axis.

As a further technical solution: in the bottom screen citation structure,

A first sealing ring is provided between the outer plane step of the front end cover and the last screen shell;

A second sealing ring is provided between the front end surface of the rear end cover and the inner plane step of the front end cover;

In the metal bellows soft connection assembly, a third sealing ring is provided between the front end surface of the rear sealing plate and the rear end surface of the rear end cover of the front connector;

A fourth sealing ring is provided between the rear end face of the rear end face of the rear sealing plate and the front end face of the pipe hard connector in the metal bellows soft connection assembly.

A further technical solution: in the downward guiding structure of the end screen, in the hard connector of the pipeline, the inner ring wall of the annular clamping groove is longer backward than the outer ring wall of the annular clamping groove.

The beneficial effects of the present invention are: using the bottom screen lead-down structure of the present invention, testers can safely, accurately and quickly complete the detection of the state quantity of the transformer bushing without power failure, and at the same time ensure that the end screen is well grounded and insulated Reliable, sealed and durable to ensure its safe operation.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

Fig. 1 is the structural representation of the embodiment of the present invention;

In the figure: 1 end screen shell, 2 insulating baffle, 3 end screen guide rod, 4 front end cover, 41 inner plane step, 42 outer plane step, 43 central cavity, 5 rear end cover, 51 central cavity, 52 inner Plane step, 53 outer plane step, 6 lead-out and fixing device, 61 insulating bushing, 62 crimping nut, 63 lead-out guide rod, 64 first blind hole, 65 spring, 66 second blind hole, 67 through hole, 68 outer Plane steps; 7 metal bellows soft connection assembly, 71 first metal bellows, 72 front connector, 73 rear connector, 74 barrel, 75 rear sealing plate, 76 through hole, 77 limit boss; 8 pipe hard Connector, 81 central cavity, 82 first external thread section, 83 boss section, 84 rear connecting section, 85 annular card slot, 86 inner ring wall, 87 outer ring wall, 9 second metal bellows, 10 end head , 101 barrel, 102 rear sealing plate, 103 through holes.

Detailed ways

As shown in Figure 1, the bottom screen structure includes the end screen shell 1, the insulating baffle plate 2, the end screen guide rod 3; A connection assembly 7 , a pipe hard connector 8 , a second metal bellows 9 , and an end head 10 .

The lead-out and fixing device 6 includes a lead-out guide rod 63 , a crimping nut 62 and an insulating bush 61 .

The metal bellows soft connection assembly 7 includes a first metal bellows 71 and two connectors respectively arranged at both ends of the first metal bellows. The two connectors are respectively denoted as a front connector 72 and a rear connector 73 .

Wherein the front end cover 4, the rear end cover 5, the lead-out guide rod 63, the front connector 72, the rear connector 73, the pipeline hard connector 8, and the end head 10 are all made of copper.

The crimping nut 62 can be a metal standard part.

The axis of the last screen guide rod 3 is the reference axis. The expressions of front and back in the following are only for the convenience of describing the relative positions adopted, and do not represent absolute positions.

The front end cover 4 is provided with a central cavity 43, and the axis of the central cavity 43 coincides with the reference axis. The inner diameter of the front part of the front end cover 4 is smaller than the inner diameter of the rear part, and a radial inner plane step 41 is formed at the junction of the front part and the rear part where the inner diameter changes. The outer diameter of the front part of the front end cover 4 is also smaller than the outer diameter of the rear part, and a radial outer plane step 42 is formed at the junction of the front part and the rear part where the outer diameter changes. The front part of the front end cover 4 is provided with an external thread and is screwed into the end screen housing 1 . The rear portion of the front end cover 4 is provided with internal threads.

In order to further improve and ensure the sealing performance between the front end cover and the end screen shell, to better protect the end screen guide rod, lead-out guide rod and lead-out wire; A first sealing ring 11 is provided between 42 and the last screen housing 1 .

The rear end cover 5 is also provided with a central cavity 51 . The inner diameter of the front part of the rear end cover 5 is larger than the inner diameter of the rear part, and a radial inner plane step 52 is formed at the junction of the front part and the rear part where the inner diameter changes. The outer diameter of the front part of the rear end cover 5 is larger than that of the rear part, and a radial outer plane step 53 is formed at the junction of the front part and the rear part where the outer diameter changes. The front part of the rear end cover 5 is connected with the internal thread at the rear of the front end cover 4 through external threads, and the central cavity 43 of the front end cover 4 and the central cavity 51 of the rear end cover 5 are coaxially connected to form an integral protective chamber. The rear portion of the rear end cover 5 is provided with external threads.

In order to further improve and ensure the sealing performance between the rear end cover and the front end cover, to better protect the end screen guide rod, lead-out guide rod and lead-out wire; A second sealing ring 12 is provided between the inner plane step 41 of the front end cover 4 .

In the described extraction and fixing device 6:

The lead-out guide rod 63 is made up of a polished rod segment at the front and a threaded segment at the rear.

A first blind hole 64 is provided in the polished rod section, and the axis of the first blind hole 64 coincides with the reference axis. The rear end of the first blind hole 64 is provided with a spring 65 that expands and contracts along the reference axis. The end screen guide rod 3 is inserted into the first blind hole 64 with gaps, and the rear end surface of the end screen guide rod 3 is in close contact with the spring 65 .

The threaded section at the rear of the lead-out guide rod 63 is provided with an external thread. A second blind hole 66 is provided in the threaded section, the axis of the second blind hole 66 coincides with the reference axis, and the front end of the second blind hole 66 is provided with four through holes 67 along the radial direction. The through-hole 67 is used for connecting the lead-out wire, and the lead-out wire passes through the through-hole and is reliably connected with the lead-out guide rod.

The crimping nut 62 is assembled on the threaded section of the lead-out guide rod 63 . In order to fix the lead-out wire passing through the through hole 67, turn the crimping nut 62 so that the crimping nut presses the lead-out wire between the crimping nut 62 and the lead-out guide rod 63, thereby reliably fixing the lead-out wire and ensuring The reliability of the connection between the lead-out wire and the lead-out guide rod 63 has been improved.

The insulating bush 61 is provided with an internal threaded hole, and is also assembled on the threaded section of the lead-out guide rod 63 through the internal threaded hole. The outer diameter of the front portion of the insulating bushing 61 is greater than the inner diameter of the rear portion of the rear end cap 5 , and the outer diameter of the rear portion of the insulating bushing 61 is smaller than the inner diameter of the rear portion of the rear end cap 5 . A radially outer plane step 68 is formed at the outer diameter change of the front and rear junctions of the insulating bush 61, and the outer plane step 68 of the insulating bush 61 cooperates with the inner plane step 52 of the rear end cover 5 to form a limit structure. The insulating bushing 61 can support the lead-out guide rod 63, so that the lead-out guide rod 63 is stably installed in the integral protective chamber formed by the front end cover 4 and the rear end cover 5, and can connect the lead-out guide rod 63 with the rear end cover 5 Insulation is separated; In addition, adjusting the position of the insulating bush 61 on the lead-out guide rod 63 can adjust the tightness of the contact between the spring 65 and the last screen guide rod 3, so as to ensure the connection between the last screen guide rod 3 and the spring 65. Reliability, no disconnection occurs.

In the metal bellows soft connection assembly 7:

The two connecting heads are composed of a cylinder body 74 and a rear sealing plate 75. The rear sealing plate 75 is connected to the rear end of the cylinder body 74 in a sealed manner, and the cylinder body 74 is provided with an internal thread. A through hole 76 is formed on the rear sealing plate 75 along the reference axis.

The two ends of the first metal bellows 71 respectively pass through the through holes 76 of the two connectors and radially outwardly extend inside the cylinder 74 to form a limiting boss 77, the limiting boss 77 The diameter is larger than the diameter of the through hole 76 . The internal thread of the barrel of the front connector 72 is matched with the external thread at the rear of the rear end cover 5 .

The pipe hard connector 8 is provided with a central cavity 81, and the axis of the central cavity 81 coincides with the reference axis. The pipe hard connector 8 includes a first external thread section 82 at the front, a boss section 83 at the middle and a rear connecting section 84 at the rear. The outer diameter of the boss section 83 is larger than the outer diameters of the first external thread section 82 and the rear connecting section 84 . The first external thread section 82 is threadedly connected to the rear connector 73 in the metal bellows flexible connection assembly 7 . The rear connecting section 84 is provided with an annular locking groove 85 on the periphery of the central cavity. The axis of the annular locking groove 85 coincides with the reference axis. The corrugation fits the helical corrugation of the pipe.

The second metal bellows 9, the inner ring wall 86 of the annular clamping groove of the pipeline hard connector 8 is screwed on the inner wall of the front end of the second metal bellows 9 . In the pipe hard connector 8 , the inner ring wall 86 of the annular locking groove 85 is longer than the outer ring wall 87 of the annular locking groove 85 backward.

The end head 10 is connected to the rear end of the cylinder 101 by the cylinder body 101, the rear sealing plate 102, and the rear sealing plate 102. The cylinder body 101 is provided with an internal helical pattern that matches the spiral corrugation of the second metal bellows 9 and screwed on the outer wall of the rear end of the second metal bellows 9 through the internal helical thread, and the rear sealing plate 102 is provided with a through hole 103 along the reference axis.

In order to further strengthen the sealing effect, protect the lead-out wires, and ensure the reliability of the lead-out, the front connector 72 in the metal bellows flexible connection assembly 7, the front end surface of the rear sealing plate and the rear end surface of the rear end cover 5 A third sealing ring 13 is provided. A fourth sealing ring 14 is provided between the rear connector 73 of the metal bellows soft connection assembly 7 , the rear end surface of the rear sealing plate and the front end surface of the pipe hard connector 8 .

When in use, the last screen guide rod, the lead-out guide rod and the lead-out wire form a conductive path to allow current to pass through. One end of the lead-out line passes through the through hole 67 and conducts with the lead-out guide rod, and the lead-out line passes through the first metal bellows 71, the pipe hard connector 8, and the second metal bellows 9 in turn, and is sealed by the end head 10 The through hole 103 on 102 leads out. During online detection, there is no need to climb on the top of the transformer main body, unscrew the end cover and other operations, which is convenient, fast and safe to operate. In this way, the grounding method outside the cover can also meet the requirements.

The front end cover 4, the rear end cover 5, the first metal bellows 71, the front connector 72, the rear connector 73, the pipe hard connector 8, the second metal bellows 9, and the end head 10 form a shielding shell to ensure the lead-out structure security.

Claims (3)

1. An end-screen down-leading structure dedicated to transformer bushing monitoring, including an end-screen housing, an insulating baffle, and an end-screen guide rod; it is characterized in that the axis of the end-screen guide rod is a reference axis; it also includes: The front end cover is provided with a central cavity; the inner diameter of the front part on the front end cover is smaller than the inner diameter of the rear part, and a radial inner plane step is formed at the change of the inner diameter at the junction of the front part and the rear part; the front part of the front end cover The outer diameter is also smaller than the outer diameter of the rear part, and a radial outer plane step is formed at the change of the outer diameter at the junction of the front part and the rear part; the front part of the front end cover is provided with external threads and is connected to the last screen shell by threads Inside, the axis of the central cavity coincides with the reference axis; the rear part of the front end cover is provided with internal threads; The rear end cover is also provided with a central cavity; the inner diameter of the front part of the rear end cover is larger than the inner diameter of the rear part, and a radial inner plane step is formed at the junction of the front part and the rear part where the inner diameter changes; the rear end cover The outer diameter of the upper front part is larger than that of the rear part, and a radial outer plane step is formed at the outer diameter change at the junction of the front part and the rear part; the front part of the rear end cover is connected with the rear part of the front end cover through external threads The internal thread connection, the central cavity of the front end cover and the central cavity of the rear end cover are coaxially connected to form an integral protective cavity; the rear part of the rear end cover is provided with external threads; The lead-out and fixing device includes a lead-out guide rod, a crimping nut, and an insulating bushing; the lead-out guide rod is composed of a polished rod segment at the front and a threaded segment at the rear, and a first blind hole is set in the polished rod segment, and the first The axis of the blind hole coincides with the reference axis; the rear end of the first blind hole is equipped with a spring that expands and contracts along the direction of the reference axis; The rear end surface of the screen guide rod is in close contact with the spring; the threaded section at the rear of the lead-out guide rod is provided with external threads; a second blind hole is arranged in the threaded section, and the axis of the second blind hole is in line with the reference The axes coincide, and the front end of the second blind hole is provided with four through holes in the radial direction; the crimping nut is assembled on the threaded section; the insulating bushing is provided with an internal threaded hole, and is also assembled on the threaded section through the internal threaded hole. On the threaded section; the outer diameter of the front part of the insulating bushing is greater than the inner diameter of the rear part of the rear end cover, and the outer diameter of the rear part of the insulating bushing is smaller than the inner diameter of the rear part of the rear end cover; the front part and the rear part of the insulating bushing are at the junction A radial outer plane step is formed at the change of the outer diameter of the outer diameter, and the outer plane step of the insulating bush cooperates with the inner plane step of the rear end cover to form a limiting structure; The metal bellows soft connection assembly includes a first metal bellows and two connectors respectively arranged at both ends of the first metal bellows, and the two connectors are respectively denoted as a front connector and a rear connector; the two connectors Both are composed of a cylinder and a rear sealing plate. The rear sealing plates of the two connectors are respectively sealed and connected to the rear ends of the corresponding connector cylinders. The cylinders of the two connectors are all provided with internal threads; the rear of the two connectors The sealing plate is provided with through holes along the reference axis; the two ends of the first metal bellows respectively pass through the through holes of the two connectors and are radially extended in the cylinders of the two connectors. A limit boss, the diameter of the limit boss is greater than the diameter of the through holes of the two connectors; the internal thread of the cylinder of the front connector cooperates with the external thread at the rear of the rear end cover; The pipe hard connector is provided with a central cavity, and the axis of the central cavity coincides with the reference axis; the pipeline hard connector includes a first external thread section at the front, a boss section at the middle and a rear connection at the rear section; the outer diameter of the boss section is greater than the outer diameter of the first external thread section and the rear connection section; the first external thread section is threaded with the rear connector in the metal bellows soft connection assembly; the rear connection section is in An annular slot is arranged on the periphery of the central cavity, the axis of the annular slot coincides with the reference axis, the opening of the annular slot faces backward, and the inner ring wall is provided with spiral threads, The second metal bellows, the inner wall of the front end of the second metal bellows is installed on the inner ring wall of the annular groove of the pipe hard connector; the spiral pattern on the inner ring wall is tightened with the spiral corrugation of the second metal bellows; The terminal head is composed of a cylinder body and a rear sealing plate. The rear sealing plate of the terminal head is sealed and connected to the rear end of the cylinder body of the terminal head. Internal helical thread; and screwed on the rear end outer wall of the second metal bellows through the internal helical thread, and the rear sealing plate of the end head is provided with a through hole along the reference axis. 2. A special end-screen down-leading structure for transformer bushing monitoring according to claim 1, characterized in that: A first sealing ring is provided between the outer plane step of the front end cover and the last screen shell; A second sealing ring is provided between the front end surface of the rear end cover and the inner plane step of the front end cover; In the metal bellows soft connection assembly, a third sealing ring is provided between the front end surface of the rear sealing plate of the front connector and the rear end surface of the rear end cover; In the metal bellows soft connection assembly, a fourth sealing ring is provided between the rear end face of the rear sealing plate of the rear connector and the front end face of the pipe hard connector. 3. According to claim 1 or 2, a transformer bushing monitoring dedicated end screen downward guide structure, characterized in that, in the hard connector of the pipeline, the inner ring wall of the annular clamping groove is longer than the rear of the annular clamping groove. outer wall.