Transformer bushing

Abstract

The application discloses a transformer bushing, comprising: an insulating tube arranged in a hollow structure in an axial direction; a capacitor core, comprising a current-carrying rod penetrating through the insulating tube, and a plurality of layers of insulating layers and a plurality of layers of capacitor screens which are sequentially wound outside the current-carrying rod and inside the insulating tube, wherein one end of the current-carrying rod extending out of the insulating tube is fixedly connected with a first wiring terminal and electrically connected with the first wiring terminal; and a last screen connector which is electrically connected with the last screen in the capacitor core and used for grounding the last screen when the transformer bushing is in operation. The transformer bushing provided by the application has a simple structure, can save cost, reduce production procedures and improve production efficiency.

Description

Technical Field

[0001] This application relates to the field of power transmission technology, and in particular to a transformer bushing. Background Technology

[0002] Transformer bushings are high-voltage devices widely used in power systems. They are fixedly installed on the transformer casing, with one end exposed outside the transformer and electrically connected to external conductors such as cables, and the other end extending into the transformer and electrically connected to the internal leads. Thus, the transformer's output current is guided to external conductors such as cables through the transformer bushing, or the current in external conductors such as cables is guided to the transformer through the transformer bushing.

[0003] Currently, capacitive bushings are divided into oil-paper capacitive bushings and adhesive-paper capacitive bushings. Oil-paper capacitive bushings are further divided into cable-carrying type and conduit current-carrying type according to their current-carrying structure. Among them, conduit current-carrying type is further divided into direct type and rod-carrying type according to the connection method between the terminal and the bushing.

[0004] The inventors of this application have discovered through long-term research that the existing oil-paper capacitor bushing structure is complex and has many components, which can easily lead to poor contact between components. Summary of the Invention

[0005] The purpose of this application is to provide a transformer bushing that can save costs, reduce production steps, and improve production efficiency.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: a transformer bushing is provided, comprising: an insulating tube configured as a hollow structure along the axial direction; a capacitor core, comprising a current-carrying rod passing through the insulating tube and multiple layers of insulating layers and multiple layers of capacitor screens sequentially wound inside the insulating tube and outside the current-carrying rod, wherein one end of the current-carrying rod extending outside the insulating tube is fixedly connected to a first terminal and electrically connected to the first terminal; and a final screen connector electrically connected to the final screen in the capacitor core, used to ground the final screen during operation of the transformer bushing.

[0007] It also includes: an oil storage tank, fixed to one end of the insulating tube and connected to the insulating tube, wherein one end of the current-carrying rod passes through the insulating tube through the oil storage tank and is fixedly connected to the first terminal located outside the oil storage tank.

[0008] The current-carrying rod is configured as a hollow structure along the axial direction, and the current-carrying rod has several through holes on its side wall located inside the insulating tube and / or the oil tank and not covered by the insulating layer and the capacitor screen.

[0009] It also includes: a first end cap that covers the other end of the current-carrying rod that extends beyond the insulating tube, and a second terminal is fixed on the side of the first end cap away from the current-carrying rod, and the first end cap is electrically connected to the current-carrying rod and the second terminal.

[0010] The device also includes: a round nut, which is tightly fitted around the current-carrying rod and seals the other end of the insulating tube, while the first end cap abuts against the end face of the round nut away from the insulating tube; and a gasket, which has an annular structure, with both the inner and outer annular surfaces being non-circular. The gasket is positioned between the current-carrying rod and the round nut, with the current-carrying rod fitting against the inner annular surface and the round nut fitting against the outer annular surface.

[0011] Specifically, the inner and outer annular surfaces of the gasket are both non-circular surfaces, including: the outer annular surface having a plurality of first slots, and the round nut having a first locking block corresponding to and cooperating with the first slots on the inner wall of the gasket; and / or, the inner annular surface having a plurality of second locking blocks, and the current-carrying rod having a second slot corresponding to and cooperating with the second locking blocks on the outer wall of the gasket.

[0012] The insulating tube includes a first sub-insulating tube and a second sub-insulating tube connected by a flange. The end of the first sub-insulating tube that is not connected to the flange is connected to the oil tank, and the end of the second sub-insulating tube that is not connected to the flange is connected to the round nut.

[0013] The end-screen connector includes: a grounding post, which is a conductive element, comprising a first end connected to the lead wire of the end screen and a second end opposite to the first end, wherein when the grounding post is inserted into the mounting hole on the flange, the second end of the grounding post is away from the mounting hole; an insulating element, sleeved around the grounding post, for isolating the hole wall of the mounting hole and the outer wall of the grounding post; a clamping element, comprising an annular plate sleeved around the insulating element and a peripheral wall extending from the inner circumference of the annular plate, wherein when the clamping element is assembled onto the flange base by a first bolt passing through the annular plate, thereby positioning the grounding post and the insulating element in the mounting hole, the clamping element is electrically connected to the flange, and the peripheral wall of the clamping element is away from the flange; and a grounding seat, which covers the clamping element and accommodates the second end of the grounding post within the grounding seat, thereby electrically connecting the clamping element and the grounding post.

[0014] The insulating component is fitted around the grounding post by a casting process, and the outer wall of the grounding post in contact with the insulating component is provided with several first grooves.

[0015] The lead wire of the end screen is wound around the second bolt, and the first end of the grounding post is provided with a second groove that corresponds to and cooperates with the second bolt, so that the second bolt can be detachably assembled in the second groove, thereby realizing the connection between the lead wire of the end screen and the first end of the grounding post.

[0016] The beneficial effects of this application are as follows: This application fixes and electrically connects one end of the current-carrying rod extending out of the insulating tube in the capacitor core to the first terminal, so that the current in the transformer can flow to the first terminal through the current-carrying rod, or the current in the first terminal can flow to the transformer through the current-carrying rod. In other words, this application directly utilizes the current-carrying rod in the capacitor core for current carrying. Compared with the prior art, where transformer bushings generally include a wound tube in the capacitor core and a current-carrying rod passing through the wound tube, this application has a simpler structure, saves costs, and eliminates the need for insulation between the wound tube and the current-carrying rod, reducing production steps and improving production efficiency. Furthermore, the transformer bushing in this application also includes a final screen connector electrically connected to the final screen in the capacitor core, which ensures the normal operation of the transformer bushing and facilitates high-voltage testing of the transformer bushing.

[0017] In addition, the transformer bushing in this application also has a washer between the current-carrying rod and the round nut. The washer has a ring structure, and its inner and outer ring surfaces are not circular, which can prevent the current-carrying rod from rotating in the transformer bushing.

[0018] Furthermore, the final shield connector of the transformer bushing in this application specifically includes a grounding post, an insulating component, a clamping component, and a grounding base. This enables capacitance and dielectric loss measurements of the transformer bushing during high-voltage testing, and grounding of the final shield during normal operation of the transformer bushing, ensuring uniform electric field distribution within the capacitor core. Compared to existing technologies, this application eliminates the need for small ceramic components, resulting in a simple and compact structure. Assembly is convenient and quick; simply assemble the grounding post, insulating component, and clamping component sequentially, then fix the clamping component to the flange with the first bolt, and finally place the grounding base onto the clamping component. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0020] Figure 1 This is a cross-sectional structural schematic diagram of one embodiment of the transformer bushing of this application;

[0021] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0022] Figure 3 yes Figure 2 Enlarged view of point B in the middle;

[0023] Figure 4 yes Figure 1 Enlarged view of point C in the middle;

[0024] Figure 5 This is an exploded structural diagram of a current-carrying rod, round nut, and gasket in an application scenario.

[0025] Figure 6 This is a schematic diagram of the front structure of a gasket in an application scenario;

[0026] Figure 7 This is a schematic diagram of the front structure of the gasket in another application scenario;

[0027] Figure 8 yes Figure 1 Enlarged view of point D in the middle;

[0028] Figure 9 yes Figure 8 Enlarged view of point E in the middle;

[0029] Figure 10 yes Figure 9 A cross-sectional structural diagram of the grounding post and insulating components;

[0030] Figure 11 yes Figure 9 A partial cross-sectional structural diagram of the middle flange. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] See Figure 1 and Figure 2 , Figure 1 This is a cross-sectional structural schematic diagram of one embodiment of the transformer bushing of this application. Figure 2 yes Figure 1Enlarged schematic diagram at point A. The transformer bushing in this application can be an oil-paper capacitor type transformer bushing, or other types of bushings, which are not limited here. The transformer bushing 1000 is installed on the transformer (not shown), specifically fixed to the transformer casing, with one end extending out of the transformer and the other end extending into the transformer interior, used to guide the current in the transformer to external conductors such as cables, or to guide the current in external conductors such as cables to the transformer. In this embodiment, the transformer bushing 1000 includes an insulating tube 1010, a capacitor core 1020, and a terminal shield connector 1030.

[0033] The insulating tube 1010 is configured as a hollow structure along the axial direction, i.e., a hollow tube. The insulating tube 1010 is made by winding fibers such as glass fiber and aramid fiber, or by molding or other processes.

[0034] The capacitor core 1020 includes a current-carrying rod 1021 passing through an insulating tube 1010, and multiple layers of insulating layers and multiple layers of capacitor screens sequentially wound inside the insulating tube 1010 and outside the current-carrying rod 1021. In order to... Figure 1 The clarity of the multi-layer insulation layer and the multi-layer capacitor screen are represented as a whole by the reference numeral 1022. Simultaneously, one end 10211 of the current-carrying rod 1021 extending beyond the insulating tube 110 is fixedly connected to and electrically connected to the first terminal 1040. Specifically, the first terminal 1040 is used to connect external conductors such as cables. When the current-carrying rod 1021 is electrically connected to the first terminal 1040, the current-carrying rod 1021 is electrically connected to the external conductor such as the cable connected to the first terminal 1040. In this embodiment, the current-carrying rod 1021 in the capacitor core 1020 is specifically used for carrying current, so that the current in the transformer flows into the first terminal 1040 through the current-carrying rod 1021, and then into the external conductor such as the cable connected to the first terminal 1040, or so that the current in the external conductor such as the cable flows sequentially through the first terminal 1040 and the current-carrying rod 1021 to the transformer. Compared to existing technologies where transformer bushings include both the coiled tube in the capacitor core and the current-carrying rod inserted in the coiled tube, the transformer bushing 1000 in this embodiment has a simple structure, saves costs, and eliminates the need for insulation between the coiled tube and the current-carrying rod, thereby reducing production steps and improving production efficiency.

[0035] The end screen connector 1030 is electrically connected to the end screen (not shown in the figure) in the capacitor core 1020, that is, the outermost layer of the capacitor screen in the capacitor core 1020. It is used to ground the end screen during the operation of the transformer bushing 1000 to ensure the uniform distribution of electric field inside the transformer bushing 1000, and to measure the capacitance and dielectric loss of the transformer bushing 1000 during high voltage tests.

[0036] As can be seen from the above, the transformer bushing 1000 in this application directly uses the current-carrying rod 1021 in the capacitor core 1020 to transmit the current between the transformer and external conductors such as cables, which is to carry current. The structure is simple, which can reduce production steps and improve production efficiency. On the other hand, the end screen connector 1030 is provided, which can not only ensure the normal operation of the transformer bushing 1000, but also facilitate high-voltage testing.

[0037] In one application scenario, one end 10211 of the current-carrying rod 1021 is directly and fixedly connected to the first terminal 1040, with no other connecting elements between them. Therefore, the current transmitted between the current-carrying rod 1021 and the first terminal 1040 does not pass through other components, reducing current transients during transmission. Furthermore, the direct fixed connection between the current-carrying rod 1021 and the first terminal 1040 also reduces the number of components in the transformer bushing 1000, ensuring good contact between components. Of course, in other application scenarios, as long as the current-carrying rod 1021 and the first terminal 1040 can be electrically connected, one end 10211 of the current-carrying rod 1021 can also be fixedly connected to the first terminal 1040 through other connecting elements; this is not a limitation.

[0038] Because the current-carrying rod 1021 in this application needs to transmit current between the transformer and external conductors such as cables, it needs to carry a large current during the operation of the transformer bushing 1000, thus generating a lot of heat. To dissipate the heat generated by the current-carrying rod 1021 in a timely manner, in one application scenario, the insulating tube 1010 is filled with transformer oil (not shown). When the transformer bushing 1000 is working, the higher-temperature transformer oil and the lower-temperature transformer oil in the insulating tube 1010 undergo convection, thereby dissipating the heat generated by the current-carrying rod 1021 and preventing it from overheating. In this application scenario, to ensure that the insulating tube 1010 is filled with transformer oil under any temperature and operating conditions, please refer to [further details omitted]. Figure 1 and Figure 2 The transformer bushing 1000 also includes an oil conservator 1050. When the volume of transformer oil in the insulating tube 1010 expands or contracts with temperature and operating conditions, the oil conservator 1050 can regulate the oil volume.

[0039] Specifically, the oil conservator 1050 is fixed to one end 10101 of the insulating tube 1010 and communicates with the insulating tube 1010. Simultaneously, one end 10211 of the current-carrying rod 1021 passes through the insulating tube 1010 into the oil conservator 1050 and is fixedly connected to the first terminal 1040 located outside the oil conservator 1050. When the volume of the transformer oil in the insulating tube 1010 expands, the excess transformer oil in the insulating tube 1010 flows to the oil conservator 1050, meaning the oil conservator 1050 serves to store oil. When the volume of the transformer oil in the insulating tube 1010 decreases, the transformer oil in the oil conservator 1050 flows to the insulating tube 1010, meaning the oil conservator 1050 serves to replenish oil.

[0040] In this application scenario, please refer to [further details]. Figure 1 and Figure 2 To further improve the heat dissipation performance of the current-carrying rod 1021, the current-carrying rod 1021 is also a hollow tube, i.e., it is a hollow structure along the axial direction. Simultaneously, several through holes 10213 are provided on the side wall 10212 of the current-carrying rod 1021 located inside the insulating tube 1010 and / or the oil conservator 1050 and not covered by the insulation layer and capacitor screen. These through holes 10213 can be located only in the insulating tube 1010 or the oil conservator 1050, or they can be distributed simultaneously in both the insulating tube 1010 and the oil conservator 1050. By providing the through holes 10213, the transformer oil can circulate between the inner and outer sides of the current-carrying rod 1021, significantly reducing the temperature of the current-carrying rod 1021. It is worth noting that, due to the skin effect of current, when current passes through a conductor, the current distribution on the conductor interface is uneven due to induction. The closer to the conductor surface, the greater the current density. Especially when the frequency of the current is very high, the current is almost only transmitted on the surface of the conductor, and almost no current passes through the inside of the conductor. Therefore, in this application scenario, the current-carrying rod 1021 is set as a hollow tube instead of a solid tube, which not only does not affect the current-carrying efficiency of the current-carrying rod 1021, but also saves materials.

[0041] Continue reading Figure 1 To further improve the fluidity of the transformer oil, several through holes 10213 are distributed on both sides of the area 10221 covered by the insulation layer and capacitor screen of the current-carrying rod 1021. By distributing several through holes 10213 on both sides of the area 10221, compared to only setting them on one side of the area 10221, the fluidity is stronger, which can accelerate the heat dissipation of the current-carrying rod 1021.

[0042] See Figure 1 , Figure 2 as well as Figure 3In one application scenario, the transformer bushing 1000 also includes a second end cap 1060 for sealing one end 10211 of the current-carrying rod 1021 that passes through the oil conservator 1050. Specifically, before assembling the transformer bushing 1000, the second end cover 1060 does not cover the current-carrying rod 1021, thus allowing the current-carrying rod 1021 to be pre-cleaned to ensure its cleanliness. After pre-cleaning the transformer bushing 1000, the second end cover 1060 is placed on one end 10211 of the current-carrying rod 1021. At this time, the second end cover 1060 and one end 10211 of the current-carrying rod 1021 can be detachably or non-detachably connected. For example, the second end cover 1060 and the current-carrying rod 1021 can be connected by threads, interference fit, or the second end cover 1060 can be directly welded to the current-carrying rod 1021. Thus, when the transformer bushing 1000 is operating normally, the second end cover 1060 can prevent transformer oil from flowing out or being invaded by external moisture.

[0043] The flow-carrying rod 1021 has a stepped portion 10214 on the inner wall of one end 10211 of the oil tank 1050 to form a first contact surface 10215 and a second contact surface 10216 that contact the second end cover 1060. The second end cover 1060 includes a flat plate 1061 and a protruding post 1062 protruding from the surface 10611 of the flat plate 1061. When the second end cover 1060 covers one end 10211 of the flow-carrying rod 1021, the protruding post 1062 extends into the flow-carrying rod 1021, causing the surface 10611 of the flat plate 1061 to abut against the first contact surface 10215, and the end face 10621 of the protruding post 1062 to abut against the second contact surface 10216.

[0044] See Figure 1 and Figure 4 In one application scenario, the transformer bushing 1000 also includes a first end cover 1070. The first end cover 1070 covers the other end 10217 of the current-carrying rod 1021 extending beyond the insulating tube 1010. Simultaneously, a second terminal 1080 is fixed to the side of the first end cover 1070 away from the current-carrying rod 1021. The first end cover 1070 electrically connects the current-carrying rod 1021 and the second terminal 1080. Specifically, the first end cover 1070 and the current-carrying rod 1021 are connected by threads or other means. The second terminal 1080 is located inside the transformer and connected to the transformer's internal leads. The second terminal 1080 is fixed to the first end cover 1070. The first end cover 1070 is a conductive element, thus the transformer's output current flows sequentially from the second terminal 1080, the first end cover 1070, the current-carrying rod 1021, to the first terminal 1040.

[0045] In order to cover the other end 10102 of the insulating tube 1010, that is, the end of the insulating tube 1010 that is not connected to the oil conservator 1050, the transformer bushing 1000 also includes a round nut 1090. The round nut 1090 is tightly fitted around the periphery of the current-carrying rod 1021 and fixed to the other end 10102 of the insulating tube 1010, thereby covering the other end 10102 of the insulating tube 1010 through the end face of the round nut 1090. At the same time, the first end cap 1070 abuts against the end face of the round nut 1090 away from the insulating tube 1010 and is fixedly connected to the round nut 1090 by bolts or other components. It should be noted that in other embodiments, the round nut 1090 may not be provided, and the other end 10217 of the current-carrying rod 1021 and the other end 10102 of the insulating tube 1010 may be covered simultaneously by the first end cap 1070.

[0046] In one application scenario, please refer to [further details]. Figure 4 The round nut 1090 is provided with an oil drain port 1200 that communicates with the insulating tube 1010, and a matching oil drain plug 1210 is installed in the oil drain port 1200. Specifically, when the transformer oil inside the insulating tube 1010 needs to be replaced, the oil drain plug 1210 is removed. At this time, since the oil drain plug 1210 is located at the end of the transformer bushing 1000, the transformer oil inside the insulating tube 1010 can be drained completely.

[0047] In the above embodiment, the transformer bushing 1000 directly carries current using the current-carrying rod 1021 in the capacitor core 1020. Since the current flowing through the current-carrying rod 1021 is generally large, and the external conductors such as the cable connected to the first terminal 1040 are relatively thick, a large torque force is generated on the current-carrying rod 1021 during the operation of the transformer bushing 1000. To prevent the current-carrying rod 1021 from rotating during the operation of the transformer bushing 1000, and to facilitate installation and fixation while preventing failure, refer to... Figure 4 and Figure 5 In another embodiment of this application, the transformer bushing 1000 further includes a gasket 1100.

[0048] The gasket 1100 has an annular structure, and both the inner annular surface 1110 and the outer annular surface 1120 of the gasket 1100 are non-circular surfaces. The gasket 1100 is fitted between the current-carrying rod 1021 and the round nut 1090. The current-carrying rod 1021 is matched and fitted with the inner annular surface 1110 of the gasket 1100, and the round nut 1090 is matched and fitted with the outer annular surface 1120 of the gasket 1100. Since the outer annular surface 1120 and the inner annular surface 1110 of the gasket 1100 are both non-circular surfaces, and the gasket 1100 is clamped between the current-carrying rod 1021 and the round nut 1090, the gasket 1100 cannot rotate relative to the round nut 1090. Consequently, the current-carrying rod 1021, which is matched and fitted with the gasket 1100, also cannot rotate relative to the round nut 1090. Since the round nut 1090 is fixedly connected to the insulating tube 1010, the current-carrying rod 1021 cannot rotate relative to the insulating tube 1010. That is, no matter how much torque is generated by the external conductor such as the cable, the current-carrying rod 1021 will not rotate in the transformer bushing 1000. Moreover, unlike the easily failed sealing ring clamping method and the inconvenient thread tightening method in the prior art, the gasket 1100 is easy to install and fix. It should be noted that, for ease of installation, the gasket 1100 is placed between the round nut 1090 and the flow-carrying rod 1021 in this embodiment. However, this application does not limit the position of the gasket 1100. In other embodiments, the gasket 1100 can also be placed in other suitable positions, such as between the flow-carrying rod 1021 and the oil tank 1050, or between the flow-carrying rod 1021 and the first end cap 1070.

[0049] In one application scenario, refer to Figure 5 , Figure 6 and Figure 7The inner ring surface 1110 and the outer ring surface 1120 of the gasket 1100 are both non-circular surfaces. Specifically, the outer ring surface 1120 of the gasket 1100 is provided with a plurality of first slots 1121. The inner wall of the round nut 1090 opposite the gasket 1100 is provided with a first locking block 1092 that corresponds to and cooperates with the first slots 1121. The outer ring surface 1120 of the gasket 1100 and the inner wall of the round nut 1090 are matched and fitted together by the first locking block 1092 and the first slots 1121 engaging with each other. The number of first slots 1121 and first locking blocks 1092 are the same, and can be one, four or more, without limitation. In another application scenario, the inner annular surface 1110 and the outer annular surface 1120 of the gasket 1100 are both non-circular surfaces. Specifically, the inner annular surface 1110 of the gasket 1100 is provided with a number of second locking blocks 1111. The outer wall of the current-carrying rod 1021 facing the gasket 1100 has a second locking groove 10218 that corresponds to and cooperates with the second locking blocks 1111. The inner annular surface 1110 of the gasket 1100 and the outer wall of the current-carrying rod 1021 are matched and fitted by the mutual locking of the second locking blocks 1111 and the second locking groove 10218. The number of the second locking groove 10218 and the second locking blocks 1111 are the same, and there can be one, three, four or more, which is not limited here. It should be noted that in other application scenarios, the inner annular surface 1110 and the outer annular surface 1120 of the gasket 1100 are not circular surfaces. Specifically, the inner annular surface 1110 and the outer annular surface 1120 of the gasket 1100 can be elliptical surfaces or other irregularly shaped surfaces. It should be noted that in this application, as long as the gasket 1100 is locked between the current-carrying rod 1021 and the round nut 1090, the current-carrying rod 1021 cannot rotate freely, the shape of the inner annular surface 1110 and the outer annular surface 1120 of the gasket 1100 is not limited.

[0050] In one application scenario, the cross-section of gasket 1100 along its central axis is an axisymmetric figure with the center of the cross-section as the symmetry point (e.g., Figure 6 (as shown) or centrally symmetric figures (such as) Figure 7 (As shown), to ensure that the gasket 1100 is subjected to uniform force and can withstand greater pressure.

[0051] In one application scenario, refer to Figure 4To further facilitate installation, the end face of the round nut 1090 away from the insulating tube 1010 is provided with a third groove 1091 for the washer 1100 to be inserted. The first end cap 1070 simultaneously abuts against the end faces of the round nut 1090 and the washer 1100. Specifically, during installation, the current-carrying rod 1021 is first passed through the insulating tube 1010 and the round nut 1090. Then, the washer 1100 is placed into the third groove 1091 from the side of the round nut 1090 away from the insulating tube 1010, so that the inner ring surface 1110 of the washer 1100 fits against the current-carrying rod 1021 and the outer ring surface 1120 fits against the round nut 1090, ultimately ensuring that the current-carrying rod 1021 cannot rotate.

[0052] In one application scenario, refer to Figure 1 , Figure 2 , Figure 4 and Figure 8 The insulating tube 1010 includes a first sub-insulating tube 1012 and a second sub-insulating tube 1013 connected by a flange 1011. One end of the first sub-insulating tube 1012, not connected to the flange 1011 (i.e., one end 10101 of the insulating tube 1010), is connected to the oil conservator 1050. The other end of the second sub-insulating tube 1013, not connected to the flange 1011 (i.e., the other end 10102 of the insulating tube 1010), is connected to a round nut 1090. When the transformer bushing 1000 is assembled onto the transformer, the transformer bushing 1000 is fixed to the transformer casing via the flange 1011. Simultaneously, the second sub-insulating tube 1013 extends into the transformer interior, while the first sub-insulating tube 1012 extends outwards from the transformer exterior. In order to protect the first sub-insulating tube 1012 extending outward, the outer periphery of the first sub-insulating tube 1012 is covered with an insulating layer 1014. The insulating layer 1014 is an integrally injection-molded silicone rubber skirt. The silicone rubber skirt has good water repellency and anti-aging properties, long service life, and can effectively protect the first sub-insulating tube 1012.

[0053] In the above embodiments, by providing an annular gasket 1100 between the current-carrying rod 1021 and the round nut 1090, and by ensuring that both the inner annular surface 1110 and the outer annular surface 1120 of the gasket 1100 are non-circular, it can be ensured that the current-carrying rod 1021 cannot rotate in the transformer bushing 1000.

[0054] See Figures 9 to 11 In another embodiment of this application, the end screen connector 1030 specifically includes: a grounding post 1031, an insulating member 1032, a clamping member 1033, and a grounding base 1034.

[0055] The grounding post 1031 is a conductive component, including a first end 10311 and a second end 10312 disposed opposite to each other. The first end 10311 of the grounding post 1031 is connected to the lead wire 1035 of the end screen (not shown). When the lead wire 1035 is connected to the first end 10311, there is a direct electrical connection between the grounding post 1031 and the lead wire 1035. The grounding post 1031 is inserted into the mounting hole 10111 on the flange 1011. At this time, the second end 10312 of the grounding post 1031 is away from the mounting hole 10111; the insulating member 1032 is made of insulating material and is sleeved around the grounding post 1031 to isolate the hole wall of the mounting hole 10111 from the outer wall of the grounding post 1031. That is, the insulating member 1032 prevents direct contact between the grounding post 1031 and the flange 1011; the clamping member 1033 includes an annular plate 1033 sleeved around the insulating member 1032. 1. And the peripheral wall 10332 extending from the inner circumference of the annular plate 10331, when the end screen connector 1030 is installed on the transformer bushing 1000, the clamping member 1033 is assembled on the flange 1011 by the first bolt 1036 passing through the annular plate 10331, thereby positioning the grounding post 1031 and the insulating member 1032 in the mounting hole 10111, and when the clamping member 1033 is fixed on the flange 1011, the clamping member 1033 and the flange 1011 are... 11. Electrical connection: The peripheral wall 10332 of the clamping member 1033 is away from the flange 1011; the grounding seat 1034 covers the clamping member 1033 and accommodates the second end 10312 of the grounding post 1031 within the grounding seat 1034, thereby electrically connecting the clamping member 1033 and the grounding post 1031. That is, when the grounding seat 1034 covers the clamping member 1033, the flange 1011, the grounding seat 1034, and the grounding post 1031 are electrically connected. In one application scenario, the clamping member 1033, the grounding seat 1034, and the grounding post 1031 are all conductive components, and the grounding post 1031, the clamping member 1033, and the grounding seat 1034 can all be made of materials such as aluminum, copper, and stainless steel.

[0056] Before the transformer bushing 1000 is in normal operation, the end screen connector 1030 is pre-assembled: the grounding post 1031 is inserted into the mounting hole 10111 of the flange 1011, and its first end 10311 is connected to the lead wire 1035 of the end screen. Then, the insulating part 1032 is sleeved on the outside of the grounding post 1031. Further, the clamping part 1033 is fixed to the flange 1011 by the first bolt 1036, so that the grounding post 1031 and the insulating part 1032 are positioned in the mounting hole 10111. Finally, the grounding seat 1034 is covered on the clamping part 1033, so that the second end 10312 of the grounding post 1031 is received in the grounding seat 1034. The grounding seat 1034 can be covered on the clamping part 1033 by means of threaded connection, interference fit connection, etc. After the end-screen connector 1030 is assembled, since flange 1011 is grounded through the transformer casing (not shown), grounding post 1031 is grounded sequentially through grounding base 1034, clamping member 1033, flange 1011, and transformer casing, thus grounding the end-screen and ensuring uniform electric field distribution inside transformer bushing 1000. During high-voltage testing of transformer bushing 1000, grounding base 1034 is directly removed. Since grounding post 1031 is insulated from flange 1011 by insulating member 1032, grounding post 1031 is no longer electrically connected to flange 1011, and the end-screen is no longer grounded. This allows for measurement of capacitance and dielectric loss of transformer bushing 1000. After the high-voltage test is completed, directly assembling grounding base 1034 on the outside of clamping member 1033 ensures the end-screen is grounded again.

[0057] As can be seen from the above, the end-screen connector 1030 in this embodiment does not require additional small ceramic parts, has a simple structure, and is conducive to the miniaturization of the transformer bushing 1000. During assembly, after placing the grounding post 1031 and the insulating component 1032 into the mounting hole 10111 and fitting the clamping component 1033, simply tighten the first bolt 1036 and the grounding seat 1034; assembly is convenient. Furthermore, during high-voltage testing, only the grounding seat 1034 needs to be removed. Since the grounding seat 1034 is separated from the grounding post 1031, personnel can directly observe the condition of the grounding post 1031 and replace it promptly if any defects are found, ensuring grounding reliability.

[0058] In one application scenario, the grounding post 1031 is cylindrical. To further reduce the volume of the end-screen connector 1030 and ensure the seal between the grounding post 1031 and the insulating component 1032 to prevent the intrusion of external moisture and dust, the insulating component 1032 is directly sleeved onto the outer periphery of the grounding post 1031 using a casting process. Specifically, during the fabrication of the end-screen connector 1030, the grounding post 1031 is placed inside a machine, and insulating materials such as polytetrafluoroethylene or epoxy resin are directly cast onto the outer side of the grounding post 1031 to form the insulating component 1032. By directly casting the insulating component 1032 onto the outer side of the grounding post 1031, the contact between the grounding post 1031 and the insulating component 1032 is strong, the sealing performance is good, and the structure is compact. Therefore, there is no need to add a sealing ring, effectively reducing the volume of the end-screen connector 1030. Of course, in other application scenarios, the grounding post 1031 and the insulating component 1032 can also be independent and detachably assembled together; this is not a limitation.

[0059] Furthermore, in this application scenario, to increase the contact area between the grounding post 1031 and the insulating component 1032 to enhance the contact strength between them, see [reference needed]. Figure 10 The outer wall of the grounding post 1031 in contact with the insulating component 1032 is provided with a plurality of first grooves 10313. The first grooves 10313 are arranged around the grounding post 1031, and the number of them can be one, two, three or more, without limitation. In addition, this application does not limit the depth of the first grooves 10313, which can be designed by the designer according to specific requirements.

[0060] In one application scenario, for easier replacement of the end-screen connector 1030, please refer to [link / reference needed]. Figure 9 and Figure 10 The lead wire 1035 of the end screen is wound around the second bolt 1037. Correspondingly, the first end 10311 of the grounding post 1031 is provided with a second groove 10314 that mates with the second bolt 1037, wherein the second bolt 1037 is detachably assembled into the second groove 10314. Specifically, one end of the lead wire 1035 of the end screen is welded to the end screen, and the other end is wound around the second bolt 1037, thereby assembling the second bolt 1037 into the second groove 10314 to achieve the connection between the lead wire 1035 of the end screen and the first end 10311 of the grounding post 1031. In this application scenario, by winding the lead wire 1035 of the end screen around the second bolt 1037, when the end screen connector 1030 needs to be replaced due to aging, accidents, or other reasons, the second bolt 1037 can be directly separated from the grounding post 1031, which is convenient to operate.

[0061] In one application scenario, refer to Figure 9 and Figure 11The mounting hole 10111 has a stepped cross-sectional shape in its axial direction, so that the mounting hole 10111 forms a bearing surface 10112 in its axial direction. When the clamping member 1033 is assembled on the flange 1011, at least a portion of the insulating member 1032 is clamped between the annular plate 10331 and the bearing surface 10112, thereby positioning the insulating member 1032 and the grounding post 1031 within the mounting hole 10111. That is, through the clamping of the clamping member 1033 and the bearing surface 10112, the grounding post 1031 and the insulating member 1032 can no longer move along the axial direction of the mounting hole 10111. In addition, to prevent the grounding post 1031 and the insulating member 1032 from moving radially along the mounting hole 10111, the insulating member 1032 is clamped by the clamping member 1033 and the bearing surface 10112, and the periphery of the portion of the insulating member 1032 is fitted with the hole wall of the mounting hole 10111. This ensures that the grounding post 1031 and the insulating member 1032 cannot move within the mounting hole 10111, i.e., they are positioned within the mounting hole 10111.

[0062] In one application scenario, refer to Figure 9 and Figure 10 In order to ensure the electrical connection between the grounding post 1031 and the grounding base 1034 when the grounding post 1031 is housed in the grounding base 1034, the second end 10312 of the grounding post 1031 is provided with a plurality of elastic metal sheets 1038, and the extending direction of the elastic metal sheets 1038 is the same as the axial direction of the grounding post 1031.

[0063] Both ends of the elastic metal sheet 1038 are fixed to the grounding post 1031. When no external force is applied, the middle portion 10381 of the elastic metal sheet 1038 expands away from the grounding post 1031. When the second end 1102 of the grounding post 1031 is housed within the grounding base 1034, the grounding base 1034 applies a force to the elastic metal sheet 1038, thereby allowing the multiple elastic metal sheets 1038 to be elastically supported between the grounding post 1031 and the grounding base 1034, thus ensuring the electrical connection between the grounding post 1031 and the grounding base 1034. The multiple elastic metal sheets 1038 are evenly spaced along the circumference of the grounding post 1031. To ensure that the multiple elastic metal sheets 1038 maintain good elasticity after repeated insertion and removal of the grounding base 1034, the elastic metal sheets 1038 are made of materials with good mechanical properties, such as copper.

[0064] See Figures 1 to 9In another embodiment of this application, the oil tank 1050 is fixedly connected to the insulating tube 1010 and the current-carrying rod 1021 by adhesive bonding. The round nut 1090 is connected to the insulating tube 1010 by adhesive bonding, and the flange 1011 is connected to the first insulating tube 1012 and the second insulating tube 1013 by adhesive bonding, respectively. Specifically, the contact surfaces of the oil tank 1050 and the insulating tube 1010, the contact surfaces of the oil tank 1050 and the current-carrying rod 1021, the contact surfaces of the round nut 1090 and the insulating tube 1010, the contact surfaces of the flange 1011 and the first insulating tube 1012, and the contact surfaces of the flange 1011 and the second insulating tube 1013 are all provided with adhesive grooves 1300. The adhesive grooves 1300 are filled with adhesive material for fixing, such as resin glue.

[0065] To further improve the sealing performance of the transformer bushing 1000, in one application scenario, the transformer bushing 1000 also includes multiple sealing rings 1400. Specifically, sealing rings 1400 are provided on the contact surfaces of the second end cover 1060 and the current-carrying rod 1021, the oil conservator 1050 and the insulating tube 1010, the insulating tube 1010 and the round nut 1090, the current-carrying rod 1021 and the round nut 1090, the first end cover 1070 and the round nut 1090, the first end cover 1070 and the current-carrying rod 1021, the grounding seat 1034 and the clamping member 1033, the clamping member 1033 and the insulating member 1032, the clamping member 1033 and the flange 1011, and the insulating member 1032 and the bearing surface 10112. By using multiple sealing rings 1400, leakage of transformer oil from the insulating tube 1010 to the outside through the contact surfaces of various components can be prevented, as well as the intrusion of external moisture and contaminants. Furthermore, some sealing rings 1400, such as the sealing ring between the insulating tube 1010 and the round nut 1090, and the sealing ring between the insulating tube 1010 and the oil conservator 1050, can also prevent the transformer oil from contacting the adhesive material in the adhesive groove 1300, thereby preventing oil contamination that could affect the electrical performance of the transformer bushing 1000. The axial cross-section of the sealing ring 1400 can be circular, rectangular, or other shapes, and is not limited here.

[0066] In summary, this application fixes and electrically connects one end of the current-carrying rod extending from the insulating tube in the capacitor core to the first terminal, allowing current in the transformer to flow to the first terminal through the current-carrying rod, or vice versa. In other words, this application directly utilizes the current-carrying rod in the capacitor core for current carrying. Compared to existing transformer bushings, which generally include a wound tube in the capacitor core and a current-carrying rod passing through it, this application has a simpler structure, saves costs, and eliminates the need for insulation between the wound tube and the current-carrying rod, reducing production steps and improving efficiency. Furthermore, the transformer bushing in this application includes a final screen connector electrically connected to the final screen in the capacitor core, ensuring normal operation of the transformer bushing and also enabling high-voltage testing.

[0067] In addition, the transformer bushing in this application also has a washer between the current-carrying rod and the round nut. The washer has a ring structure, and its inner and outer ring surfaces are not circular, which can prevent the current-carrying rod from rotating in the transformer bushing.

[0068] Furthermore, the transformer bushing end screen connector in this application specifically includes a grounding post, an insulating component, a clamping component, and a grounding seat. It enables capacitance and dielectric loss measurements of the transformer bushing during high-voltage testing, and grounds the end screen during normal operation of the transformer bushing, ensuring uniform electric field distribution within the capacitor core. Compared to existing technologies, this application eliminates the need for small ceramic components, resulting in a simple and compact structure. Assembly is convenient and quick; simply assemble the grounding post, insulating component, and clamping component sequentially, then fix the clamping component to the flange with the first bolt, and finally place the grounding seat on top of the clamping component.

[0069] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A transformer bushing characterized by, The transformer bushing comprises: an insulating tube arranged in an axial direction as a hollow structure; a capacitor core comprising a current-carrying rod penetrating the insulating tube and a plurality of layers of insulating layers and a plurality of layers of capacitor screens successively wound outside the current-carrying rod inside the insulating tube, wherein one end of the current-carrying rod extending out of the insulating tube is fixedly connected with and electrically connected to a first terminal; a terminal screen connector electrically connected to the terminal screen in the capacitor core and used for grounding the terminal screen when the transformer bushing is in operation; a round nut tightly sleeved on the periphery of the current-carrying rod and covering the other end of the insulating tube, wherein the round nut is provided with a drain opening in communication with the insulating tube, and a matched drain plug is assembled in the drain opening; a gasket, which is an annular structure, wherein the inner and outer annular surfaces of the gasket are both non-circular surfaces, the gasket is clamped between the current-carrying rod and the round nut, the current-carrying rod is matched and fitted with the inner annular surface, and the round nut is matched and fitted with the outer annular surface. The inner and outer annular surfaces of the gasket are both non-circular surfaces, specifically comprising: the outer annular surface is provided with a plurality of first clamping grooves, and the inner wall of the round nut opposite to the gasket is provided with a plurality of first clamping blocks corresponding to and matched with the first clamping grooves; and the inner annular surface is provided with a plurality of second clamping blocks, and the outer wall of the current-carrying rod opposite to the gasket is provided with a plurality of second clamping grooves corresponding to and matched with the second clamping blocks.

2. The transformer bushing of claim 1, wherein, Further comprising: an oil storage tank fixed to one end of the insulating tube and in communication with the insulating tube, wherein the one end of the current-carrying rod penetrates the oil storage tank and is fixedly connected with the first terminal located outside the oil storage tank.

3. The transformer bushing according to claim 2, wherein the current-carrying rod is arranged in an axial direction as a hollow structure, and the side wall of the current-carrying rod located inside the insulating tube and / or the oil storage tank and not covered by the insulating layers and the capacitor screens is provided with a plurality of through holes.

4. The transformer bushing of claim 2, wherein, Further comprising: a first end cover covering the other end of the current-carrying rod extending out of the insulating tube, wherein a second terminal is fixed to the side of the first end cover away from the current-carrying rod, the first end cover electrically connects the current-carrying rod and the second terminal, and the first end cover abuts against the end surface of the round nut away from the insulating tube.

5. The transformer bushing according to claim 2, wherein the insulating tube comprises a first sub-insulating tube and a second sub-insulating tube connected by a flange, the first sub-insulating tube is connected with the oil storage tank at one end not connected with the flange, and the second sub-insulating tube is connected with the round nut at one end not connected with the flange.

6. The transformer bushing of claim 5, wherein, The terminal screen connector comprises: a grounding column, which is a conductive member and comprises a first end portion connected with the lead-out wire of the terminal screen and a second end portion opposite to the first end portion, wherein when the grounding column is inserted into a mounting hole on the flange, the second end portion of the grounding column is away from the mounting hole; an insulating member sleeved on the periphery of the grounding column and used for isolating the hole wall of the mounting hole and the outer wall of the grounding column. The compression member includes a ring plate sleeved on the periphery of the insulating member and a peripheral wall extending from the inner periphery of the ring plate, wherein when the compression member is assembled on the flange base by passing a first bolt through the ring plate to position the grounding column and the insulating member in the mounting hole, the compression member is electrically connected with the flange, and the peripheral wall of the compression member is away from the flange. The grounding seat covers the compression member and accommodates the second end of the grounding column in the grounding seat, thereby electrically connecting the compression member with the grounding column.

7. The transformer bushing according to claim 6, characterized in that The insulating member is sleeved on the periphery of the grounding column by a casting process, and the outer wall of the grounding column in contact with the insulating member is provided with a plurality of first grooves.

8. The transformer bushing according to claim 6, characterized in that The lead-out wire of the terminal screen is wound on a second bolt, and the first end of the grounding column is provided with a second groove corresponding to the second bolt to enable the second bolt to be detachably assembled in the second groove, thereby realizing the connection between the lead-out wire of the terminal screen and the first end of the grounding column.

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