Embedded vacuum OLTC real-time current and voltage test structure

Abstract

This invention relates to an embedded vacuum OLTC real-time current and voltage testing structure, comprising a sensor vacuum tube installed inside the core, replacing the conventional vacuum tube. The sensor vacuum tube includes a first vacuum tube and a current or voltage sensor for measuring the first vacuum tube. The internal induction wire of the current or voltage sensor is connected to an external signal processing unit via a connection structure. In use, this invention directly replaces the conventional vacuum tube within the core by installing the sensor vacuum tube, which integrates the current or voltage sensor. The internal induction wire is connected to the external signal processing unit via the connection structure, enabling real-time online acquisition of current and voltage signals during the OLTC vacuum tube switching process. This solution does not require alteration to the original switch body structure; in-situ replacement provides access to the internal electrical parameters of the vacuum tube, offering a direct and accurate data source for condition monitoring and fault early warning.

Description

Technical Field

[0001] This invention relates to the field of machinery, and more particularly to the field of mechanical component technology, specifically to an embedded vacuum OLTC real-time current and voltage testing structure. Background Technology

[0002] The on-load tap changer is the only movable component in an on-load tap-changing transformer. Through its regulation, it reduces and avoids large voltage fluctuations, distributes load flow, ensures the safe and reliable operation of the power system, and increases the flexibility of grid dispatch. As power systems place higher demands on stability and power quality control, the requirements for transformer voltage regulation and stability are further enhanced, consequently increasing the requirements for the reliability and stability of the on-load tap changer. The operating status of each component during actual on-load tap changer switching is the fundamental data for improving reliability and stability.

[0003] Currently, there are many external sensors on the market that indirectly detect the switching process. However, there is no way to directly detect the current and voltage of devices during the switching process in actual operation of tap changers. How to directly embed sensors to measure the actual switching process of the tap changer without affecting the performance of the original structure, so as to truly obtain the actual operating status of the tap changer, is an urgent problem to be solved. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing an embedded vacuum OLTC real-time current and voltage testing structure to solve the problem that existing technologies cannot perform real-time, online monitoring of the electrical parameters of OLTC vacuum tubes, thereby improving the tap changer's operational status sensing capability.

[0005] This invention is achieved through the following technical solution.

[0006] When in use, the present invention provides an embedded vacuum OLTC real-time current and voltage testing structure, which includes a sensor vacuum tube installed in the core instead of a conventional vacuum tube. The sensor vacuum tube includes a first vacuum tube and a current or voltage sensor for measuring the first vacuum tube. The internal induction wire of the current or voltage sensor is connected to an external signal processing unit through a connection structure.

[0007] In use, this invention directly replaces the conventional vacuum tube with a sensor vacuum tube installed within the core. The sensor vacuum tube integrates a current or voltage sensor, and its internal sensing wire is connected to an external signal processing unit via a connection structure, enabling real-time online acquisition of current and voltage signals during the OLTC vacuum tube switching process. This solution requires no alteration to the original switch body structure; in-situ replacement provides access to the internal electrical parameters of the vacuum tube, offering a direct and accurate data source for condition monitoring and fault early warning.

[0008] As an optimization, the sensor vacuum tube includes an insulating support and an insulating cover located between the insulating support and the first vacuum tube. The insulating support is provided with a mounting groove for mounting the current or voltage sensor. The sensor vacuum tube also includes the insulating cover, the current or voltage sensor, and a current connection block that pass through sequentially. The current connection block has a through hole for the lower fixing bolt to pass through.

[0009] In this optimized design, an insulating bracket, insulating cover, mounting slot, current connection block, and lower fixing bolt are further incorporated into the sensor vacuum tube, forming a compact and reliable mechanical fixing and electrical connection structure. The insulating bracket and insulating cover ensure electrical isolation between the sensor and the vacuum tube; the mounting slot precisely positions the sensor; and the cooperation between the current connection block and the lower fixing bolt achieves a stable mechanical connection and current path, improving the sensor's resistance to switching shocks and its measurement stability.

[0010] Preferably, the first flange connecting the small cylinder of the core to the oil chamber cylinder is integrally formed with the top cover of the switch as a change flange. The top cover of the switch is connected to the transformer bushing. The top of the small cylinder is fixedly connected to a gasket flange that is connected to the change flange. The height of the small cylinder with the change flange is higher than the height of the original small cylinder.

[0011] In this preferred embodiment, the first flange connecting the small cylinder of the core to the oil chamber cylinder is integrally formed with the top cover of the switch as a modified flange, and is connected to the top of the small cylinder with a gasket flange. This greatly simplifies the assembly structure between the top of the switch and the transformer bushing, saves the use of sealing rings, and thus reduces the height. Therefore, compared with the original small cylinder, the height of the existing small cylinder is increased.

[0012] This design reduces the number of parts and installation steps, enhances connection rigidity and alignment, and provides a smooth and continuous path for the internal induction wire to run from the inside of the small cylinder to the top of the transformer bushing, which is beneficial to the sealing and insulation of the signal transmission path.

[0013] As an optimization, the connection structure includes a jumper connection plate installed at the top of the transformer bushing, the inner sensing line of the current or voltage sensor is connected from bottom to top to the lower interface of the jumper connection plate, and the outer sensing line of the signal processing unit located at the upper end of the transformer bushing is connected to the upper interface of the jumper connection plate.

[0014] This optimization scheme achieves reliable isolation and transfer of high and low voltage side induction lines by setting a jumper connection plate at the top of the transformer bushing, with the inner induction line connected to the lower interface of the jumper connection plate from bottom to top, and the outer induction line connected to the upper interface of the jumper connection plate from top to bottom.

[0015] This jumper connector can be flexibly configured with a certain number of interfaces, facilitating the simultaneous transmission and maintenance of multiple signals and significantly improving the security and anti-interference capability of signal transmission.

[0016] As an optimization, the insulating support is equipped with a spacer tube separating the current or voltage sensor and the current connection block. This optimization, by setting the spacer tube on the insulating support, separates the current or voltage sensor from the current connection block, increasing the creepage distance and electrical clearance between them, effectively preventing surface discharge or breakdown from high potential to low potential. Simultaneously, the spacer tube structure provides auxiliary positioning and limiting for the sensor and current connection block, avoiding relative displacement during assembly and ensuring the consistency of the sensor's measurement gap.

[0017] As an optimization, the bottom surface of the small tube is provided with two oppositely arranged wire inlets. A fixing plate is also provided between the wire inlets and the sensor vacuum tube. The fixing plate has adapter holes for all internal sensing wires to pass through. Several internal sensing wires are divided into two groups and pass through the adapter holes, and then enter the small tube from the two wire inlets respectively. The small tube is also provided with cable ties to bind the internal sensing wires.

[0018] This optimized design features two opposing cable inlets on the bottom of the tube, along with a fixing plate with adapter holes. Several internal induction wires are divided into two groups, passing through the adapter holes and entering the tube through the two inlets respectively, before being bundled together with cable ties. This wiring structure achieves grouping and orderly exit of the internal induction wires, avoiding insulation damage or signal crosstalk caused by wire bundle entanglement or compression. The fixing plate effectively limits the bending radius of the wire bundle at the inlets, and the cable ties ensure the integrity of the wire bundle inside the tube, thereby improving the reliability of signal transmission and the internal insulation safety of the switch.

[0019] The beneficial effects of this invention are: in-situ replacement without changing the main structure, using a sensor vacuum tube to directly replace the conventional vacuum tube installed in the core, without requiring major modifications to the main mechanical structure of the OLTC, and easy to upgrade existing equipment; Real-time online monitoring: The embedded current or voltage sensor can collect current and voltage signals during the vacuum tube switching process in real time and transmit them to the external signal processing unit through the internal induction line to realize online status assessment. The signal transmission is reliable. The inner and outer induction wires are isolated and connected at the top of the transformer bushing through the jumper connection panel to avoid electrical interference between the high-voltage side and the low-voltage side, and the signal transmission is stable. The wiring is neat and safe. The design of the inlet, fixing plate and cable tie at the bottom of the tube allows multiple internal induction wires to enter the tube in a group and in an orderly manner, preventing insulation failure or mechanical damage caused by messy wiring. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is an exploded view of the sensor's vacuum tube. Figure 3This is a schematic diagram showing the connection between the sensor vacuum tube and the lower fixing plate; Figure 4 This is a simplified structural view of the present invention; Figure 5 A schematic diagram showing the change at the connection between the flange and the transformer bushing; As shown in the figure: 1. Sensor vacuum tube; 2. Oil chamber cylinder; 3. Small cylinder; 4. Several internal induction wires; 5. Transformer bushing; 6. Signal processing unit; 11. Internal induction wire; 12. Current connection block; 13. Insulating frame cover; 14. Voltage or current sensor; 15. Insulating support; 16. Spacing tube; 17. First vacuum tube; 18. Lower fixing plate; 19. Lower fixing bolt; 20. Upper fixing plate; 30. Fixing plate; 31. Cable tie; 32. Changing flange; 60. Internal connector; 61. Jumper wire connection plate; 62. External induction wire. Detailed Implementation To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to describe the solution.

[0021] See attached document Figure 1-5 This invention discloses an embedded vacuum OLTC real-time current and voltage testing structure. This structure is mainly used in on-load tap changers (OLTCs) of power transformers to achieve real-time, online monitoring of current and voltage during vacuum tube switching.

[0022] The test structure includes a sensor vacuum tube 1 that replaces the conventional vacuum tube. The sensor vacuum tube 1 is fully compatible with the conventional vacuum tube in terms of physical size and interface, and can directly replace the original vacuum tube and be installed inside the core.

[0023] The sensor vacuum tube 1 includes a first vacuum tube 17 (maintaining its original vacuum arc-extinguishing function) and a current or voltage sensor, specifically a Rogowski coil, for measuring the electrical parameters of the first vacuum tube 17. The internal induction wire 11 of the current or voltage sensor is ultimately connected to an external signal processing unit 6 (e.g., a data acquisition card, DSP, or MCU) through a connection structure.

[0024] The sensor vacuum tube 1 includes an insulating support 15 and an insulating cover 13. The insulating cover 13 is sandwiched between the insulating support 15 and the first vacuum tube 17, providing electrical insulation and fixed support. A mounting slot specifically designed to accommodate a current or voltage sensor is provided on the insulating support 15.

[0025] The conventional vacuum tube is installed on the upper and lower fixed plates. The upper end of the sensor vacuum tube 1 has the same structure as the upper end of the conventional sensor, that is, the two connection structures with the upper fixed plate 20 are the same.

[0026] During assembly, the lower fixing bolt 19 passes through the lower fixing plate, the insulating frame cover 13, the center hole of the current or voltage sensor, and the through hole on the current connection block 12, and is threaded to the bottom of the first vacuum tube. At the same time, the bolt head of the lower fixing bolt makes contact with the lower fixing plate.

[0027] An insulating support 15 is also provided with a spacer tube 16, which separates the current or voltage sensor from the current connection block 12 by a certain distance.

[0028] To accommodate the embedded structure, the core's fixing method has been optimized. Traditionally, the core's small cylinder 3 is connected to the oil chamber cylinder 2 via a first flange. In this embodiment, the first flange is integrally cast with the switch top cover as a single modified flange 32.

[0029] The switch top cover is then connected to the transformer bushing 5. At the same time, a gasket flange is fixedly welded to the top of the small cylinder 3, and this gasket flange is directly bolted to the modified flange 32, thereby achieving a compact fixation of the small cylinder 3, the core, and the top structure of the transformer.

[0030] The change in flange 32 significantly simplifies the assembly structure between the top of the switch and the transformer bushing 5, saves on the use of sealing rings, and thus reduces the height. Therefore, compared with the original small cylinder 3, the height of the existing small cylinder 3 is increased.

[0031] The connection structure primarily employs a jumper connector 61, which is mounted at the top of the transformer bushing 5. The inner sensing wire 11 of the current or voltage sensor runs upwards from inside the small cylinder 3, connecting to an inner connector 60. The inner connector 60 connects to the jumper connector 61 from its lower interface. Correspondingly, the external signal processing unit 6, located at the upper end of the transformer bushing 5, extends an outer sensing wire 62, connecting to an outer connector, which in turn connects to the upper interface of the jumper connector 61. Both the inner connector 60 and the outer connector are SMA connectors, one male and one female.

[0032] The jumper connection panel 61 is equipped with conductive jumpers to achieve a one-to-one connection between the inner induction line 11 and the outer induction line 62. This ensures signal conduction and also uses the height of the transformer bushing 5 to isolate the high and low voltage sides.

[0033] Two opposing wire inlets are formed on the bottom surface of the small tube 3. A fixing plate 30 is installed along the path between the wire inlets and the sensor vacuum tube 1. Multiple adapter holes are formed on the fixing plate 30 according to the number and thickness of the internal sensing wires 11. The multiple internal sensing wires 11 are divided into two symmetrical groups, each group passing through the corresponding adapter hole on the fixing plate 30, and then entering the small tube 3 through the two wire inlets. After entering the small tube 3, all the internal sensing wires 11 are bundled together with a cable tie 31 to prevent loosening and shaking, ensuring insulation safety.

[0034] Working principle: When the OLTC performs a tap switching operation, the current and voltage within the first vacuum tube 17 change. An embedded current or voltage sensor detects these changes in real time and generates corresponding analog signals. These signals are transmitted to the external signal processing unit 6 via the internal induction line 11, jumper connector 61, and external induction line 62. The signal processing unit 6 conditions, converts analog to digital, and analyzes the signals to obtain the current and voltage waveforms of the vacuum tube during the switching process in real time. This allows it to determine if there are any fault characteristics such as abnormal arcing or delayed shutdown, enabling online monitoring and early warning of the OLTC vacuum tube's status.

[0035] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. An embedded vacuum OLTC real-time current and voltage testing structure, characterized in that: The sensor vacuum tube (1) installed in the core body instead of a conventional vacuum tube includes a first vacuum tube (17) and a current or voltage sensor for measuring the first vacuum tube (17). The internal induction line (11) of the current or voltage sensor is connected to an external signal processing unit (6) through a connection structure.

2. The embedded vacuum OLTC real-time current and voltage testing structure according to claim 1, characterized in that: The sensor vacuum tube (1) includes an insulating support (15) and an insulating cover (13) located between the insulating support (15) and the first vacuum tube (17). The insulating support (15) is provided with a mounting groove for mounting the current or voltage sensor. The sensor vacuum tube (1) also includes the insulating cover (13), the current or voltage sensor, and the current connecting block (12) passing through it in sequence. The current connecting block (12) has a through hole for the lower fixing bolt (19) to pass through.

3. The embedded vacuum OLTC real-time current and voltage testing structure according to claim 1, characterized in that: The first flange connecting the small cylinder (3) of the core to the oil chamber cylinder (2) is integrally formed with the switch top cover as a change flange (32). The switch top cover is connected to the transformer bushing (5). The top of the oil chamber cylinder (2) is fixed with a gasket flange connected to the change flange (32). The height of the small cylinder (3) with the change flange (32) is higher than that of the original small cylinder (3).

4. The embedded vacuum OLTC real-time current and voltage testing structure according to claim 1, characterized in that: The connection structure includes a jumper connection plate (61) installed at the top of the transformer bushing (5), the inner sensing line (11) of the current or voltage sensor is connected from bottom to top to the lower interface of the jumper connection plate (61), and the outer sensing line (62) of the signal processing unit (6) located at the upper end of the transformer bushing (5) is connected to the upper interface of the jumper connection plate (61).

5. The embedded vacuum OLTC real-time current and voltage testing structure according to claim 2, characterized in that: The insulating support (15) is provided with a spacer tube (16) for spacer current or voltage sensors and current connection blocks (12).

6. The embedded vacuum OLTC real-time current and voltage testing structure according to claim 1, characterized in that: The bottom surface of the small tube (3) is provided with two oppositely arranged inlet ports. A fixing plate (30) is also provided between the inlet ports and the sensor vacuum tube (1). The fixing plate (30) is provided with adapter holes for all the internal sensing wires (11) to pass through. Several internal sensing wires (4) are divided into two groups and pass through the adapter holes, and then enter the small tube (3) from the two inlet ports respectively. The small tube (3) is also provided with cable ties (31) for bundling the internal sensing wires (11).

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