阅读说明：本技术 一种油浸倒立式电流互感器的拆解和缺陷排查方法 (Disassembling and defect checking method for oil-immersed inverted current transformer ) 是由 王琼 杨波 车传强 刘卓 刘天宇 窦冰杰 杨文良 李奇 于 2021-08-11 设计创作，主要内容包括：本发明提供了一种油浸倒立式电流互感器的拆解和缺陷排查方法,属于电气工程技术领域。该方法包括六个步骤。基于油浸倒立式电流互感器的结构特点和包扎工艺,针对方法所述的拆解外部组配件、检查器身外观、拆除器身主绝缘并排查缺陷等三个关键步骤,方法提出了更为详尽的拆解和排查实施方法。本发明可较快速地拆解笨重的油浸倒立式电流互感器,可提高拆解效率,可规避由于拆解不当而引起排查未果或者排查错误的风险。同时,本发明所述的每一步拆解步骤中,都提及了缺陷排查的要点位置和可能的缺陷形式,实施步骤明确,技术指导性强,更利于电力技术人员查找缺陷位置和推测缺陷成因。(The invention provides a method for disassembling and defect checking of an oil-immersed inverted current transformer, and belongs to the technical field of electrical engineering. The method comprises six steps. Based on the structural characteristics and the wrapping process of the oil-immersed inverted current transformer, the method provides a more detailed disassembling and troubleshooting implementation method aiming at three key steps of disassembling external assembly parts, checking the appearance of the transformer body, disassembling the main insulation of the transformer body, troubleshooting defects and the like. The invention can disassemble the heavy oil-immersed inverted current transformer quickly, improve the disassembling efficiency and avoid the risk of failure in investigation or error in investigation caused by improper disassembly. Meanwhile, in each step of disassembling, the invention refers to the key point position and possible defect forms of defect troubleshooting, has definite implementation steps and strong technical guidance, and is more beneficial to electric power technicians to search the defect position and guess the cause of the defect.)

1. A method for disassembling and defect checking of an oil-immersed inverted current transformer is disclosed, wherein the defect refers to a defect existing in a body of the oil-immersed inverted current transformer; the oil immersed inverted current transformer with the defects in the body is recorded as a transformer to be disassembled, the disassembling and defect troubleshooting method is used for carrying out on the transformer to be disassembled, namely, defect troubleshooting is carried out in the disassembling process of the transformer to be disassembled, and the method is characterized by comprising the following steps of:

step 1, preparation work before disassembly

Recording the equipment structure information of the mutual inductor to be disassembled into a defect checking system of the oil-immersed current mutual inductor;

testing the electrical parameters and the insulating oil performance of the mutual inductor to be disassembled by using a testing device (42) in the defect troubleshooting system;

unscrewing an exhaust plug (10), checking the sealing state of the expander (9), and reserving an insulating oil sample and emptying insulating oil;

step 2, disassembling external assembly parts

After a secondary lead-out wire (16) of the mutual inductor to be disassembled is cut off, sequentially removing external components of the mutual inductor to be disassembled, wherein the external components comprise an expander outer cover (1), a base (7), a secondary terminal box (6), an expander (9), a primary terminal (3) and a primary conductive tube (11), a porcelain sleeve (5) and an oil storage cabinet (4) which are connected with the primary terminal box, so as to obtain a transformer body (12) of the mutual inductor to be disassembled;

the following investigations were carried out in sequence: the sealing condition of the secondary terminal box (6), the appearance and the connection condition of a secondary terminal and a secondary outgoing line (16) in the secondary terminal box (6), the surface ablation and scratch condition of the primary conductive tube (11), the inner wall fouling condition of the oil storage cabinet (4) and the sealing condition of an interface of the oil storage cabinet (4) and the expander (9);

step 3, checking the appearance of the device body (12)

After the external components are disassembled, the separated transformer body (12) is vertically hung, and the annular part (19) of the transformer body (12) is downward when the transformer body is hung;

checking whether the straight line part (20), the triangular area (26) and the annular part (19) of the body (12) have local deformation or not, and whether surface damage and/or ablation and/or abnormal phenomena of impurity adsorption exist or not in sequence from top to bottom; in particular, whether the triangular zone (26) transitions smoothly from the wrapping portion of the annular portion (19) to the linear portion (20);

removing the wrinkle paper tape protective layer of the bundle on the outermost surface of the transformer body (12), and thus, seeing the high-voltage cable paper tape on the outermost layer of the transformer body (12), namely, seeing the outer surface of the main insulation (14) of the transformer body;

step 4, disassembling the body (12) and checking defects

According to the equipment structure information in the step 1, recording the number of main capacitive screens of the current transformer to be disassembled as j +2, wherein j is a positive integer, recording the outermost high-voltage screen (21) as the j +1 th screen, and recording the innermost low-voltage screen (23) as the 0 th screen; except for the j +1 th screen and the 0 th screen, the other j main capacitive screens are all intermediate screens (22), any intermediate screen (22) is recorded as a k screen, and k belongs to j; in particular, if the transformer to be disassembled has no intermediate screen (22), j is 0, k is 0;

checking the surface of the paper tape of the outermost high-voltage cable, and checking whether the wrapped high-voltage cable paper tape has an abnormal phenomenon of ablation and/or carbonization and/or X wax precipitation;

in the disassembling process, the number of the main capacitive screens and the forming mode of each main capacitive screen are checked according to the information input in the step 1;

step 4.1, annular part (19) and triangular region (26)

Whether the abnormal phenomenon of hollowing exists in the pressing triangle area (26) or not and whether the abnormal sound of 'squeaking' is generated during pressing or not;

dismantling the high-voltage cable paper tape, the tooth paper and the insulating contraction tape bound by the annular part (19) and the triangular area (26), and checking whether the high-voltage cable paper tape has abnormal phenomena of binding holes and/or deformation and/or ablation and perforation; the high-voltage cable paper tape is stripped layer by layer after the blade point is horizontally scratched;

checking whether the outermost high-voltage screen (21) is complete or not, whether abnormal phenomena of abrasion and/or cracking exist or not, whether foreign matters and/or discharge traces exist on the surface or not, and whether abnormal phenomena of folds and/or damage and/or X wax precipitation exist on aluminum foils or copper foils bound on the inner ring and the outer ring of the high-voltage screen (21); welding a high-voltage screen lead wire (13) on an aluminum foil or a copper foil of a high-voltage screen (21), and checking whether the welding of the position is firm and whether the abnormal phenomena of ablation and/or carbonization traces exist at the welding spot and the periphery of the welding spot;

pressing the triangular area (26) to determine whether the abnormal phenomena of empty drum exist or not, and checking whether the abnormal phenomena of local deformation, surface damage and/or ablation and/or impurity adsorption exist or not; if so, recording the defect position according to a clock partition recording method;

the clock partition recording method comprises the following steps: when a ring part (19) of a body (12) of the mutual inductor to be disassembled is hung downwards, the position where a straight line part (20) is inserted into the ring part (19) is taken as twelve points, and the ring part is divided according to the area of twelve hours and the like of a clock;

after the high-voltage screen (21) is removed, the bound high-voltage cable paper tape, the tooth paper and the insulation contraction tape are continuously removed;

sequentially removing and investigating high-voltage cable paper tapes, tooth paper, fold paper, k screens (when k is not equal to 0) and low-voltage screens (23) bound between the main capacitive screens;

after the annular part (19) and the main insulation (14) of the transformer body bound by the triangular area (26) are completely removed, the plugging condition of the secondary winding shielding cover (17), the annular part (19) and the linear part (20) can be seen; checking whether the inner ring and the outer ring of the outer surface of the secondary winding shielding case (17) have ablation and/or carbonization trace abnormal phenomena;

step 4.2, straight line part (20)

Checking the plugging condition of the annular part (19) and the straight line part (20), and checking whether the appearance of the straight line part (20) is intact from the bottom to the top from the plugging position; whether the abnormal phenomenon of the cavity exists at the step wrapping position presented by the straight line part (20) corresponding to the plugging position or not;

the main insulation (14) of the transformer body bound outside the secondary lead tube (15) is removed; peeling the insulating paper or the high-voltage cable paper tape, each main capacitor screen and the end screen (24) layer by layer from outside to inside, and checking whether an abnormal phenomenon exists or not; when the low-voltage screen is dismounted to the low-voltage screen (23), whether the low-voltage screen lead wire (25) is abnormal is checked, and the method is the same as the method for checking the high-voltage screen lead wire (13); the abnormal phenomenon is the same as the step 4.1;

specifically, the main insulation (14) of the transformer body bound outside the secondary lead tube (15) is used for binding a high-voltage cable paper tape, and after the blade is horizontally scratched, the blade is stripped and checked at the same time; if the paper is insulating paper, after the paper is vertically separated, the whole piece of insulating paper is stripped and checked;

the low-voltage screen (23) is removed, and then the secondary lead tube (15) can be seen after the insulating paper or the high-voltage cable paper tape between the low-voltage screen (23) and the secondary lead tube (15) is removed; checking the appearance of the secondary lead pipe (15);

photographing and recording the abnormal phenomena in the step 4 into a defect troubleshooting system of the oil-immersed current transformer, and storing the sample;

step 5, checking the secondary winding

Cutting the secondary winding shielding cover (17) along the original welding line of the secondary winding shielding cover, and taking out the secondary winding (18);

checking the secondary windings (18) one by one, and checking whether the bonding of the secondary windings (18) is firm, and whether the winding surface has or not damages and/or discharge traces and other abnormal phenomena;

particularly, when the iron core of the secondary winding (18) is suspected to be overheated, the copper wire and the insulating film on the surface of the secondary winding (18) are disassembled;

step 6, testing retention sample

And (4) testing the retained sample in the step (4) by using a sample detection device (43) in the defect inspection system of the oil-immersed current transformer.

In the disassembling and checking process, all checking results are recorded into a defect checking system of the oil-immersed inverted current transformer in real time.

2. The method for disassembling and defect inspection of the oil-immersed inverted current transformer according to claim 1, wherein the defect inspection system of the oil-immersed current transformer comprises an information input module (41), a testing device (42), a sample detection device (43), a central processing module (44), a disassembling process recording module (45), a defect diagnosis module (46) and an information output module (47).

3. The method for disassembling and troubleshooting the oil-immersed inverted current transformer according to claim 1, wherein the device structure information in the step 1 is obtained by using a device structure drawing of the oil-immersed inverted current transformer, and at least comprises: the number of the main capacitive screens and the forming mode of each main capacitive screen are recorded in a binding way of a body of a triangular area (26), and the number of end screens (23) between adjacent main capacitive screens of the straight line part (20) is recorded; and (4) the weight of the insulating oil of the mutual inductor body to be disassembled.

4. The method for disassembling and defect-checking an oil-immersed inverted current transformer according to claim 1, wherein the recording of the number of the main capacitive screens and the configuration of each main capacitive screen in the step 4 specifically includes:

1) the number of the main capacitive screens: the high-voltage screen (21), the j middle screens (22) and the low-voltage screen (23) are sequentially arranged from the outside to the inside of the main capacitive screen;

2) the main materials of each main capacitive screen comprise semiconductor crepe paper, aluminum foil or copper foil; the auxiliary material comprises crepe paper and an insulating contraction band; the insulating shrink band is used for fixing the main insulating material bound by the triangular area (26) and the annular part (19).

Technical Field

The invention belongs to the field of electrical engineering, and relates to a method for disassembling and defect checking of an oil-immersed inverted current transformer.

Background

A primary conductive tube of the oil immersed inverted current transformer penetrates through a secondary winding shielding cover containing a secondary winding in a straight tube form and is connected onto a transformer substation lead by using a primary terminal. The secondary winding is placed in the secondary winding shielding case, and the secondary lead wire passes through a secondary lead wire tube inserted in the center of the lower side of the secondary winding shielding case and is finally connected to the secondary terminal board. The whole secondary winding part and the insulating material wrapped by the same form a main body of the oil-immersed inverted current transformer, and the main body is immersed in insulating oil, so that the basic function of converting large current into small current by the current transformer is realized.

The disassembly is an effective means for analyzing and conjecturing the defect cause of the oil-immersed current transformer. The defect causes such as ablation carbonization of the insulating medium, wrinkle or breakage of the aluminum foil paper, displacement of parts caused by improper transportation and the like can be verified by a disassembling means. However, the reasons that the equipment structure, the disassembling experience, the disassembling step and the disassembling method of the oil-immersed current transformer are not familiar, are not standardized enough, and the disassembling method is not thorough enough, the defect troubleshooting process performed by disassembling is not a result, so that the requirement for estimating and diagnosing the defect cause of the oil-immersed current transformer cannot be met.

Disclosure of Invention

The invention aims to provide a method for disassembling an oil immersed inverted current transformer body and a defect checking process thereof aiming at an equipment structure of the oil immersed inverted current transformer and common defect types of the oil immersed inverted current transformer, in particular to standardize the disassembling step of the oil immersed inverted current transformer and clarify the defect checking method in the disassembling process, and provide powerful support for accurately guessing and judging the defect cause of the oil immersed inverted current transformer.

The object of the invention is thus achieved. The invention provides a method for disassembling and checking defects of an oil-immersed inverted current transformer, wherein the defects refer to the defects existing in the body of the oil-immersed inverted current transformer; the oil immersed inverted current transformer with the defects in the body is recorded as a transformer to be disassembled, the disassembling and defect troubleshooting method is used for carrying out on the transformer to be disassembled, namely, defect troubleshooting is carried out in the disassembling process of the transformer to be disassembled, and the method is characterized by comprising the following steps of:

step 1, preparation work before disassembly

Recording the equipment structure information of the mutual inductor to be disassembled into a defect checking system of the oil-immersed current mutual inductor;

testing the electrical parameters and the insulating oil performance of the mutual inductor to be disassembled by using a testing device in the defect troubleshooting system;

unscrewing an exhaust plug, checking the sealing state of the expander, and reserving an insulating oil sample and emptying insulating oil;

step 2, disassembling external assembly parts

Cutting off a secondary lead-out wire of the mutual inductor to be disassembled, and then sequentially disassembling external components of the mutual inductor to be disassembled, wherein the external components comprise an expander outer cover, a base, a secondary terminal box, an expander, a primary terminal, a primary conductive tube connected with the primary terminal, a porcelain bushing and an oil conservator, so as to obtain a transformer body of the mutual inductor to be disassembled;

the following investigations were carried out in sequence: the sealing condition of a secondary terminal box, the appearance and the connection condition of a secondary terminal and a secondary outgoing line in the secondary terminal box, the ablation and scratch condition of the surface of a primary conductive tube, the dirt condition of the inner wall of an oil storage cabinet and the sealing condition of an interface of the oil storage cabinet and an expander;

step 3, checking the appearance of the device body

After the external components are disassembled, the stripped transformer body is vertically hung, and the annular part of the transformer body is downward when the transformer body is hung;

sequentially checking whether the straight line part, the triangular area and the annular part of the transformer body have local deformation or not, and whether the surface damage and/or ablation and/or impurity adsorption abnormal phenomena exist or not from top to bottom; in particular, whether the triangular section transitions smoothly from the wrapping portion of the annular section to the linear section;

removing the fold paper tape protective layer of the bundle on the outermost surface of the transformer body, and thus, the high-voltage cable paper tape on the outermost layer of the transformer body can be seen, namely, the main insulated outer surface of the transformer body can be seen;

step 4, disassembling the body and checking defects

According to the equipment structure information in the step 1, recording the number of main capacitive screens of the current transformer to be disassembled as j +2, wherein j is a positive integer, recording the outermost high-voltage screen as the j +1 th screen, and recording the innermost low-voltage screen as the 0 th screen; except for the j +1 th screen and the 0 th screen, all the other j main capacitive screens are intermediate screens, any one of the intermediate screens is taken as a k screen, and k belongs to j; in particular, if the transformer to be disassembled has no intermediate screen, j is 0, and k is 0;

checking the surface of the paper tape of the outermost high-voltage cable, and checking whether the wrapped high-voltage cable paper tape has an abnormal phenomenon of ablation and/or carbonization and/or X wax precipitation;

in the disassembling process, the number of the main capacitive screens and the forming mode of each main capacitive screen are checked according to the information input in the step 1;

step 4.1, annular part and triangular region

Whether the abnormal phenomenon of hollowing exists in the pressing triangle area or not and whether the abnormal sound of 'squeaking' is generated during pressing or not;

dismantling the high-voltage cable paper tape, the tooth paper and the insulating contraction tape bound by the annular part and the triangular area, and checking whether the high-voltage cable paper tape has a binding cavity and/or deformation and/or ablation and has an abnormal phenomenon of perforation; the high-voltage cable paper tape is stripped layer by layer after the blade point is horizontally scratched;

checking whether the outermost high-voltage screen is complete or not, whether abnormal phenomena of abrasion and/or cracking exist or not, whether foreign matters and/or discharge traces exist on the surface or not, and whether abnormal phenomena of folds and/or damage and/or X wax precipitation exist on aluminum foils or copper foils wrapped by inner rings and outer rings of the high-voltage screen or not; welding a high-voltage screen lead-out wire on a high-voltage screen aluminum foil or a copper foil, and checking whether the welding at the position is firm and whether the abnormal phenomena of ablation and/or carbonization traces exist at the welding spot and the periphery of the welding spot;

pressing the triangular area to determine whether the abnormal phenomena of hollowing exist or not, and checking whether the abnormal phenomena of local deformation, surface damage and/or ablation and/or impurity adsorption exist or not; if so, recording the defect position according to a clock partition recording method;

the clock partition recording method comprises the following steps: when the annular part of the transformer body of the mutual inductor to be disassembled is suspended downwards, the position where the linear part is inserted into the annular part is used as twelve points, and the annular part is divided according to the twelve-hour equal area of the clock;

after the high-voltage screen is removed, the bound high-voltage cable paper tape, the tooth paper and the insulation contraction tape are continuously removed;

sequentially removing and checking a high-voltage cable paper tape, tooth paper, fold paper, k screens (when k is not equal to 0) of the middle screens and low-voltage screens bound between the main capacitive screens;

after the main insulation of the transformer body bound by the annular part and the triangular area is completely removed, the plugging condition of the secondary winding shielding cover, the annular part and the linear part can be seen; checking whether the inner ring and the outer ring of the outer surface of the secondary winding shielding case have ablation and/or carbonization trace abnormal phenomena;

step 4.2, straight line section

Checking the plugging condition of the annular part and the straight line part, and checking whether the appearance of the straight line part is intact from bottom to top from the plugging position; whether the abnormal phenomenon of holes exists at the step wrapping position presented by the straight line part corresponding to the plugging position or not;

removing the main insulation of the transformer body bound outside the secondary lead pipe; peeling the insulating paper or the high-voltage cable paper tape, each main capacitor screen and each end screen layer by layer from outside to inside, and checking whether an abnormal phenomenon exists or not; when the low-voltage screen is dismounted, whether the outgoing line of the low-voltage screen is abnormal is checked, and the method is the same as the method for checking the outgoing line of the high-voltage screen; the abnormal phenomenon is the same as the step 4.1;

specifically, the main insulation of the body wrapped outside the secondary lead pipe is wrapped with a high-voltage cable paper tape, and the blade is removed and checked while being horizontally scratched; if the paper is insulating paper, after the paper is vertically separated, the whole piece of insulating paper is stripped and checked;

removing the low-voltage screen, and then removing the insulating paper or the high-voltage cable paper tape between the low-voltage screen and the secondary lead tube, so that the secondary lead tube can be seen; checking the appearance of the secondary lead pipe;

photographing and recording the abnormal phenomena in the step 4 into a defect troubleshooting system of the oil-immersed current transformer, and storing the sample;

step 5, checking the secondary winding

Cutting the secondary winding shielding cover along the original welding line of the secondary winding shielding cover, and taking out the secondary winding;

checking the secondary windings one by one, and checking whether the bonding of the secondary windings is firm, and whether the winding surface has or not damages and/or discharge traces and other abnormal phenomena;

particularly, when the secondary winding iron core is suspected to be overheated, the copper wire and the insulating film on the surface of the secondary winding are disassembled;

step 6, testing retention sample

And (4) testing the retained sample in the step (4) by using a sample detection device in the defect inspection system of the oil-immersed current transformer.

In the disassembling and checking process, all checking results are recorded into a defect checking system of the oil-immersed inverted current transformer in real time.

Preferably, the defect troubleshooting system of the oil-immersed current transformer comprises an information input module, a testing device, a sample detection device, a central processing module, a disassembly process recording module, a defect diagnosis module and an information output module.

Preferably, the device structure information in step 1 is obtained by using a device structure drawing of the oil-immersed inverted current transformer, and at least includes: the number of the main capacitive screens and the forming mode of each main capacitive screen are recorded in a binding way of the body of the triangular area, and the number of end screens between adjacent main capacitive screens on the straight line part is recorded; and (4) the weight of the insulating oil of the mutual inductor body to be disassembled.

Preferably, the recording of the number of the main capacitive screens and the configuration of each main capacitive screen in step 4 specifically includes:

1) the number of the main capacitive screens: the high-voltage screen, the j middle screens and the low-voltage screen are sequentially arranged from the outside to the inside of the main capacitive screen;

2) the main materials of each main capacitive screen comprise semiconductor crepe paper, aluminum foil or copper foil; the auxiliary material comprises crepe paper and an insulating contraction band; the insulating contraction band is used for fixing the main insulating materials bound by the triangular area and the annular part.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention fully considers the equipment structure of the oil-immersed inverted current transformer, the binding material of the main stream of the oil-immersed inverted current transformer and the process flow, and the method defines the disassembling step of the oil-immersed inverted current transformer step by step. The method can enable technicians to quickly go to the hands and realize independent disassembly and analysis.

The invention can rapidly disassemble the heavy oil-immersed inverted current transformer, improve the disassembling efficiency and avoid the risk of failure in investigation or error in investigation caused by improper disassembly.

3. In each step of disassembling, the invention provides the main point position and possible defect form of defect investigation, which is beneficial for electric power technicians to search defect positions and guess defect causes.

4. The method is matched with a defect checking system of the oil-immersed inverted current transformer for use, processes the disassembling method of the oil-immersed inverted current transformer and the technical key points of defect checking, can more efficiently service the defect diagnosis of the oil-immersed inverted current transformer, solves the practical difficulty of production, and accumulates technical experience.

Drawings

FIG. 1 is a schematic diagram of the steps of the present invention.

Fig. 2 is an appearance schematic diagram of the oil-immersed inverted current transformer.

Fig. 3 is a left side view of fig. 2.

Fig. 4 is a longitudinal sectional view of fig. 2.

Fig. 5 is a schematic diagram of a main capacitor screen and an end screen in the transformer body shown in fig. 4.

Fig. 6 is a longitudinal schematic view of the body of fig. 3.

Fig. 7 is a defect inspection system of the oil-immersed current transformer corresponding to the method.

In the figure: 1. an expander housing; 2. an oil level observation window; 3. a primary terminal; 4. an oil conservator; 5. a porcelain bushing; 6. a secondary terminal box; 7. a base; 8. an oil drain valve; 9. an expander; 10. an exhaust valve; 11. a primary conductive tube; 12. a body; 13. a high-voltage screen lead-out wire; 14. the main insulation of the transformer body; 15. a secondary lead tube; 16. secondary lead wire outlet; 17. a secondary winding shield; 18. a secondary winding; 19. an annular portion; 20. a straight line portion; 21. a high voltage screen; 22. a middle screen; 23. a low voltage screen; 24. end screen; 25. a low voltage screen lead-out wire; 26. a triangular area; 41. an information input module; 42. a testing device; 43. a sample detection device; 44. a central processing module; 45. disassembling the process recording module; 46. defect diagnosis module information; and 47, outputting the module.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The invention provides a method for disassembling and checking defects of an oil-immersed inverted current transformer, wherein the defects refer to the defects of a body of the oil-immersed inverted current transformer. The oil immersed inverted current transformer with the defects in the body is recorded as a transformer to be disassembled, and the disassembling and defect checking method is used for carrying out on the transformer to be disassembled, namely, defect checking is carried out in the disassembling process of the transformer to be disassembled.

FIG. 1 is a schematic diagram of the steps of the method of the present invention, and as can be seen from FIG. 1, the disassembling and defect inspection method comprises the following steps:

step 1, preparation work before disassembly

Recording the equipment structure information of the mutual inductor to be disassembled into a defect checking system of the oil-immersed current mutual inductor;

testing the electrical parameters and the insulating oil performance of the mutual inductor to be disassembled by using a testing device 42 in the defect troubleshooting system;

and unscrewing the vent plug 10, checking the sealing state of the expander 9, reserving the insulating oil sample, and emptying the insulating oil.

In this embodiment, the device structure information in step 1 is obtained by using a device structure drawing of the oil-immersed inverted current transformer, and at least includes: the number of the main capacitive screens and the forming mode of each main capacitive screen are recorded in a binding mode of a triangular area 26, and the number of end screens 23 between adjacent main capacitive screens of the straight line part 20 is recorded; and (4) the weight of the insulating oil of the mutual inductor body to be disassembled.

In this embodiment, the number of the main capacitive screens and the configuration of each main capacitive screen specifically refer to:

1) the number of the main capacitive screens: the high-voltage screen 21, the j middle screens 22 and the low-voltage screen 23 are sequentially arranged from the outside to the inside of the main capacitive screen;

2) the main materials of each main capacitive screen comprise semiconductor crepe paper, aluminum foil or copper foil; the auxiliary material comprises crepe paper and an insulating contraction band; the insulating shrink band is used to secure the primary insulation wrapped by the triangular section 26 and the annular section 19.

Step 2, disassembling external assembly parts

After a secondary lead-out wire 16 of the mutual inductor to be disassembled is cut off, sequentially disassembling external components of the mutual inductor to be disassembled, wherein the external components comprise an expander outer cover 1, a base 7, a secondary terminal box 6, an expander 9, a primary terminal 3, a primary conductive tube 11, a porcelain bushing 5 and an oil storage cabinet 4 which are connected with the primary terminal 3, and obtaining an instrument body 12 of the mutual inductor to be disassembled;

the following investigations were carried out in sequence: the sealing condition of the secondary terminal box 6, the appearance and the connection condition of the secondary terminal and the secondary leading-out wire 16 in the secondary terminal box 6, the ablation and scratch conditions of the surface of the primary conductive tube 11, the dirt condition of the inner wall of the oil storage cabinet 4 and the sealing condition of the interface of the oil storage cabinet 4 and the expander 9.

Step 3, checking the appearance of the device body 12

After the outer assembly is disassembled, the separated body 12 is vertically hung, and the annular part 19 of the body 12 is downward when the body is hung;

checking whether the straight line part 20, the triangular area 26 and the annular part 19 of the body 12 have local deformation, surface damage and/or ablation and/or abnormal phenomena of impurity adsorption from top to bottom in sequence; in particular, whether the triangular section 26 transitions smoothly from the wrapping portion of the annular portion 19 to the linear portion 20;

and (3) removing the folded paper tape protection layer of the bundle on the outermost surface of the transformer body 12, and thus, seeing the high-voltage cable paper tape on the outermost layer of the transformer body 12, namely, seeing the outer surface of the main insulation 14 of the transformer body.

Step 4, disassembling the body 12 and checking for defects

According to the equipment structure information in the step 1, recording the number of main capacitive screens of the current transformer to be disassembled as j +2, wherein j is a positive integer, recording the outermost high-voltage screen 21 as the j +1 th screen, and recording the innermost low-voltage screen 23 as the 0 th screen; except for the j +1 th screen and the 0 th screen, the other j main capacitive screens are all intermediate screens 22, any one of the intermediate screens 22 is taken as a k screen, and k belongs to j; in particular, if the transformer to be disassembled has no intermediate screen 22, j is 0, k is 0;

checking the surface of the paper tape of the outermost high-voltage cable, and checking whether the wrapped high-voltage cable paper tape has an abnormal phenomenon of ablation and/or carbonization and/or X wax precipitation;

in the disassembling process, the number of the main capacitive screens and the forming mode of each main capacitive screen are checked according to the information input in the step 1; and recording is performed.

The specific disassembly process is as follows:

step 4.1, annular part 19 and triangular region 26

Whether the abnormal phenomenon of hollowing exists in the pressing triangle area 26 or not and whether the abnormal sound of 'squeaking' is generated during pressing or not;

removing the high-voltage cable paper tape, the tooth paper and the insulating contraction tape bound by the annular part 19 and the triangular area 26, and checking whether the high-voltage cable paper tape has the abnormal phenomena of binding holes and/or deformation and/or ablation and perforation; the high-voltage cable paper tape is stripped layer by layer after the blade point is horizontally scratched;

checking whether the outermost high-voltage screen 21 is complete or not, whether abnormal phenomena of abrasion and/or cracking exist or not, whether foreign matters and/or discharge traces exist on the surface or not, and whether abnormal phenomena of folds and/or damage and/or X wax precipitation exist on aluminum foils or copper foils wrapped by the inner ring and the outer ring of the high-voltage screen 21 or not; welding the high-voltage screen lead-out wire 13 on the aluminum foil or the copper foil of the high-voltage screen 21, and checking whether the welding at the position is firm and whether the abnormal phenomena of ablation and/or carbonization marks exist at the welding spot and the periphery of the welding spot;

pressing the triangular area 26 to determine whether the abnormal phenomena of empty drum exists or not, and checking whether the abnormal phenomena of local deformation, surface damage and/or ablation and/or impurity adsorption exist or not; if so, recording the defect position according to a clock partition recording method;

the clock partition recording method comprises the following steps: when the ring part 19 of the body 12 of the mutual inductor to be disassembled is hung downward, the position where the straight line part 20 is inserted into the ring part 19 is taken as twelve points, and the two points are divided according to the area of twelve hours and the like of the clock;

after the high-voltage screen 21 is removed, the bound high-voltage cable paper tape, the tooth paper and the insulation contraction tape are continuously removed;

sequentially removing and checking the high-voltage cable paper tape, the tooth paper, the crumpled paper, 22k screens (when k is not equal to 0) of the middle screens and 23 of the low-voltage screens bound between the main capacitive screens;

after the main insulation 14 of the transformer body bound by the annular part 19 and the triangular area 26 is completely removed, the plugging condition of the secondary winding shielding cover 17, the annular part 19 and the linear part 20 can be seen; and (3) inspecting whether the inner ring and the outer ring of the outer surface of the secondary winding shielding case 17 have ablation and/or carbonization traces.

In the embodiment, the high-voltage screen 21 of the mutual inductor to be disassembled consists of two layers of semiconductor crepe paper and one layer of aluminum foil, and the aluminum foil is bound between the two layers of semiconductor crepe paper; the semiconductor crepe paper on the outer layer is wrapped with a layer of crepe paper.

In the present embodiment, the inner ring and the outer ring of the high-voltage screen 21, i.e. the inner part and the outer part of the annular portion 19, are wrapped with the material of the high-voltage screen 21, which covers the inner ring and the outer ring (i.e. the cylindrical curved surface of the inner ring and the circular curved surface of the outer ring) of the secondary winding shielding case 17 in fig. 5, respectively, and are denoted by 17-1 and 17-2 in fig. 5.

In this embodiment, referring to fig. 6, the components of the transformer body 12 to be disassembled include from inside to outside: the transformer comprises a secondary winding 18, a secondary winding shielding case 17, a secondary lead tube 15, a secondary lead wire 16, a high-voltage screen 21, a high-voltage screen lead wire 13, a middle screen 22, an end screen 24, a low-voltage screen 23, a low-voltage screen lead wire 25, a high-voltage cable paper tape, a crepe paper, an insulating contraction tape and a crepe paper tape protection layer wrapping the outermost layer of the transformer body 12.

In this embodiment, as shown in fig. 5, the triangular area 26 eight o' clock direction semi-conductive crepe paper of the transformer to be disassembled has perforation anomaly phenomenon, and the diameter of the perforation is about 3 cm.

Step 4.2, straight section 20

Checking the plugging condition of the annular part 19 and the straight line part 20, and checking whether the appearance of the straight line part 20 is intact from the plugging position from bottom to top; whether the abnormal phenomenon of the cavity exists at the step wrapping position presented by the straight line part 20 corresponding to the plugging position;

the main insulation 14 of the transformer body bound outside the secondary lead tube 15 is removed; peeling the insulating paper or the high-voltage cable paper tape, each main capacitive screen and the end screen 24 layer by layer from outside to inside, and checking whether an abnormal phenomenon exists or not; when the low-voltage screen 23 is dismounted, whether the low-voltage screen lead-out wire 25 is abnormal is checked, and the method is the same as the method for checking the high-voltage screen lead-out wire 13; the abnormal phenomenon is the same as the step 4.1;

specifically, if the main insulation 14 of the body wrapped outside the secondary lead tube 15 is wrapped with a high-voltage cable paper tape, the blade is peeled off and checked after being horizontally scratched; if the paper is insulating paper, after the paper is vertically separated, the whole piece of insulating paper is stripped and checked;

the low-voltage screen 23 is removed, and then the secondary lead tube 15 can be seen after the insulating paper or the high-voltage cable paper tape between the low-voltage screen 23 and the secondary lead tube 15 is removed; checking the appearance of the secondary lead tube 15;

and 4, photographing and recording the abnormal phenomena in the step 4 into a defect troubleshooting system of the oil-immersed current transformer, and storing the sample.

Step 5, checking the secondary winding

Cutting the secondary winding shielding cover 17 along the original welding line thereof, and taking out the secondary winding 18;

checking the secondary windings 18 one by one to check whether the bonding of the secondary windings 18 is firm, and whether the winding surface has abnormal phenomena such as damage and/or discharge traces;

in particular, when the core of the secondary winding 18 is suspected of overheating, the copper wire and the insulating film on the surface of the secondary winding 18 are disassembled.

In this embodiment, one of the three secondary windings 18 shown in fig. 6 is removed, and the thermal field distribution of the secondary winding 18 is tested using an infrared thermal imager at 10 times the rated current.

Step 6, testing retention sample

And (4) testing the retained sample in the step (4) by using a sample detection device 43 in a defect inspection system of the oil-immersed current transformer.

In the disassembling and checking process, all checking results are recorded into a defect checking system of the oil-immersed inverted current transformer in real time.

Fig. 7 is a structural diagram of a defect inspection system of an oil-immersed current transformer, which can be used for inspecting an oil-immersed inverted current transformer, where the oil-immersed current transformer to be inspected is hereinafter referred to as a transformer to be disassembled, and as can be seen from the diagram, in this embodiment, the defect inspection system of the oil-immersed current transformer includes an information input module 41, a testing device 42, a sample detection device 43, a central processing module 44, a disassembly process recording module 45, a defect diagnosis module 46, and an information output module 47.

The information input module 41 is unidirectionally connected with the central processing module 44 and the disassembly process recording module 45, and transmits the structural information, the defect information and the historical test data of the mutual inductor to be disassembled to the central processing module 44 and transmits the structural information of the mutual inductor to be disassembled to the disassembly process recording module 45.

The test device 42 includes at least: the device comprises an insulation resistance tester, a direct current resistance tester, a high-voltage dielectric loss and capacitance tester, a partial discharge tester, an oil dissolved gas tester, an oil moisture content detector and an oil voltage withstand detector, wherein the insulation resistance tester, the direct current resistance tester, the high-voltage dielectric loss and capacitance tester and the partial discharge tester are used for testing the electrical parameters of the mutual inductor to be disassembled, and the oil dissolved gas tester, the oil moisture content detector and the oil voltage withstand detector are used for detecting the insulating oil performance of the mutual inductor to be disassembled; the testing device 42 is connected with the central processing module 44 in a unidirectional manner, and is used for transmitting the testing and detection results of the testing device 42 to the central processing module 44.

The sample detection device 43 is bidirectionally connected with the disassembly process recording module 45, receives disassembly, detection and sampling commands of the disassembly process recording module 45, photographs the disassembly process and detects the taken sample according to the disassembly investigation steps of the mutual inductor to be disassembled prestored in the disassembly process recording module 45, and transmits the photographed photographs and sample detection information to the disassembly process recording module 45; the sample detection device 43 comprises a camera, a galvanometer scanner, an element energy spectrum analyzer and a temperature-controllable sample soaking device, and is used for shooting a to-be-disassembled mutual inductor disassembling process and detecting a sample taken in the to-be-disassembled mutual inductor disassembling process.

The disassembly process recording module 45 is connected with the sample detection device 43 in a bidirectional way and is connected with the defect diagnosis module 46 in a unidirectional way; the disassembly process recording module 45 sends disassembly, detection and sampling commands to the sample detection device 43 according to the pre-stored disassembly and investigation steps of the mutual inductor to be disassembled, receives the pictures and the sample detection information obtained by the sample detection device 43, and transmits the integrated disassembly information to the defect diagnosis module 46 after matching and corresponding to the disassembly steps of the mutual inductor to be disassembled.

The central processing module 44 is unidirectionally connected with the information input module 41, the testing device 42 and the defect diagnosis module 46; the central processing module 44 receives the information transmitted by the information input module 41 and the testing device 42, screens and combs the information, and then transmits the effective information after screening and combing of the mutual inductor to be disassembled to the defect diagnosis module 46.

The defect diagnosis module 46 is connected with the central processing module 44, the disassembly process recording module 45 and the information output module 47 in a one-way mode; the defect diagnosis module 46 receives the effective information of the mutual inductor to be disassembled after being screened and combed, which is transmitted by the central processing module 44, and receives the disassembly information integrated by the disassembly process recording module 45, and the defect cause of the mutual inductor to be disassembled is given after analysis and diagnosis, and is transmitted to the information output module 47.

In this embodiment, the disassembling steps in the disassembling and defect checking method for the oil-immersed inverted current transformer are prestored in the disassembling process recording module 45.

Fig. 2-6 show the structure of the oil-immersed inverted current transformer, wherein fig. 2 is an appearance schematic diagram of the oil-immersed inverted current transformer, and fig. 3 is a left side view of fig. 2. Fig. 4 is a longitudinal sectional view of fig. 2. Fig. 5 is a schematic diagram of a main capacitor screen and an end screen in the transformer body shown in fig. 4. Fig. 6 is a longitudinal schematic view of the body of fig. 3.

In fig. 2 and 3: the visible inverted current transformer appearance component is from top to bottom: expander dustcoat 1, expander dustcoat 1 oil level observation window 2, primary terminal 3, oil conservator 4, insulator 5, secondary terminal box 6, base 7, and the fuel outlet valve 8 of base 7 bottommost. In fig. 2 and 3, the conservator 4 is divided into an upper part and a lower part, the body 12 is a part within a broken line frame, the main body insulator 14 is a shaded part in fig. 4, and the secondary winding shield 17 is indicated by a thick line in fig. 4.

In the cross-sectional view shown in fig. 4, the primary conductive tube 11 of the oil-immersed inverted current transformer is connected to a substation lead by the primary terminal 3 after passing through a secondary winding shield 17 containing a secondary winding 18 in a straight tube form. The secondary winding 18 is placed in a secondary winding shield 17, and the secondary lead 16 passes through a secondary lead tube 15 inserted in the center of the lower side of the secondary winding shield 17 and is finally connected to a secondary terminal plate in the secondary terminal box 6. The whole secondary winding part and the insulating material wrapped by the same form a main body of the oil-immersed inverted current transformer, and the main body is immersed in insulating oil. In fig. 4, the expander 9 is connected to the conservator 4 and is provided at its upper end with a vent valve 10.

The body 12 is composed of a ring part 19, a straight part 20 and a triangular area 26 which is a connecting part of the ring part and the straight part, and comprises a secondary winding 18, a secondary winding shielding case 17, a secondary lead pipe 15, a secondary lead wire 16, a high-voltage screen 21, a high-voltage screen lead wire 13, a middle screen 22, an end screen 24, a low-voltage screen 23 and a low-voltage screen lead wire 25, a high-voltage cable paper tape, a crepe paper and an insulation contraction tape which are wrapped among the parts, and a crepe paper tape protective layer (namely, a main insulation 14) which is wrapped on the outermost layer of the body 12.

FIG. 6 is a longitudinal view of the body taken along the line of central symmetry of FIG. 3;

in fig. 5, 3 secondary windings 18 are counted, 17-1 indicates the inner ring of the secondary winding shield 17, and 17-2 indicates the outer ring of the secondary winding shield 17.

In fig. 5 and 6, the triangular region (26) is in the form of a "triangular" area.