Transformer winding-to-ground low-energy discharge defect simulation device and system

Abstract

This invention provides a device and system for simulating low-energy discharge defects of transformer windings to ground, belonging to the field of transformer fault simulation. The device includes: a power-taking device, a high-impedance transformer, an insulating conduit, a low-energy discharge defect model, and wires. The power-taking device is connected to the beginning of the low-voltage winding of the high-impedance transformer and is positioned at a predetermined distance from the beginning of the low-voltage winding. The insulating conduit is fixed to the power-taking device. The low-energy discharge defect model, located inside the insulating conduit, is in contact with the power-taking device and is led out of the insulating conduit and grounded via wires. This invention, through the power-taking device connected to the beginning of the low-voltage winding of the high-impedance transformer and the low-energy discharge defect model, can simulate low-energy discharge defects of the winding coil to ground without causing losses to the transformer coil, thereby helping to improve the transformer maintenance skills and the ability of maintenance personnel to analyze and diagnose transformer fault causes.

Description

Technical Field

[0001] This invention relates to the field of transformer fault simulation technology, and in particular to a device and system for simulating low-energy discharge defects of transformer windings to ground. Background Technology

[0002] Transformers are very important electrical facilities in power systems. In order to ensure the safe operation of transformers, maintenance is usually carried out in combination with relevant electrical and physical-chemical tests. Defect simulation is an effective means to improve the maintenance skills of maintenance personnel.

[0003] The causes of problems in oil-immersed transformers are generally divided into two categories: external and internal. External causes are relatively easy to simulate, while some internal causes are easy to detect during operation but difficult to detect when not in operation. Moreover, some internal causes occur randomly and cannot be artificially simulated. Even if artificial simulation is possible, some defect tests can damage the transformer itself. When the destructive impact exceeds a critical value, it will lead to transformer problems, and subsequent maintenance will be very troublesome. For example, when artificially creating an inter-turn short circuit, the short circuit test increases the winding current, causing the coil to heat up and damage the winding insulation, making the winding prone to burnout and resulting in significant transformer losses. After artificially creating an inter-turn short circuit, the transformer body needs to be lifted for maintenance. Each time the transformer body is lifted, impurities can easily enter the transformer, causing unnecessary discharges when voltage is applied, affecting the maintenance progress. Furthermore, destructive tests cannot perfectly control the occurrence and cessation of the test; failure to stop and handle the problem in time can lead to winding deformation and damage.

[0004] Therefore, simulating defects without causing damage to the transformer has become crucial for improving the maintenance skills of maintenance personnel. Currently, some defect simulation devices for partial discharge inside transformers have emerged. For example, Chinese Patent CN202210679642.3, published on August 8, 2023, discloses a transformer internal defect simulation device, including a transformer body and independent oil chambers. The transformer body includes a casing, a core, and windings mounted on the core. The core and windings are both located inside the casing, and at least part of the independent oil chamber is located inside the casing. A partial discharge defect model is installed inside the independent oil chamber to simulate transformer defects. This separates the transformer oil inside the independent oil chamber from the transformer body, ensuring that the insulation performance of the transformer body is not degraded by partial discharge, while simplifying the replacement of partial discharge defects. Furthermore, the use of multiple independent oil chambers allows for the simulation of different phases, locations, and types of partial discharge in the transformer. However, currently, there is no suitable device for simulating low-energy discharge defects from transformer windings to ground. Summary of the Invention

[0005] This invention provides a device and system for simulating low-energy discharge defects of transformer windings to ground, in order to solve the problem of how to simulate low-energy discharge defects of transformer windings to ground.

[0006] In a first aspect, embodiments of the present invention provide a transformer winding to ground low-energy discharge defect simulation device, comprising: a power extraction device, a high-impedance transformer, an insulating conduit, a low-energy discharge defect model, and a wire;

[0007] The power extraction device is connected to the first end of the low-voltage winding of the high-impedance transformer and is located at a predetermined distance from the first end of the low-voltage winding.

[0008] The insulating conduit is fixed to the power supply device;

[0009] The low-energy discharge defect model disposed within the insulating conduit is in contact with the power extraction device and is led out of the insulating conduit and grounded via the wire.

[0010] In one possible implementation, the high-impedance transformer is a transformer including an axially split winding, the power taking device is connected to the first end of the axially split winding, and is located at a predetermined distance from the first end of the axially split winding.

[0011] In one possible implementation, the preset distance is 3 to 10 cm.

[0012] In one possible implementation, the low-energy discharge defect model includes: a model skeleton, an iron core, coils, an isolation post, a metal needle, a spring, a screw, and a copper post;

[0013] The iron core is fixedly disposed at one end of the model skeleton, and one end of the iron core is located in the cavity formed by the model skeleton;

[0014] The isolation column is disposed at the other end of the iron core;

[0015] The copper pillar is disposed on the isolation pillar, and the copper pillar is welded to the wire;

[0016] The coil is wound around the perimeter of the model skeleton;

[0017] The metal needle is fixedly disposed at the other end of the model skeleton, and the metal needle and the iron core are connected by the spring;

[0018] The screw is fixed below the metal needle by the model skeleton, and the screw is in contact with the power-generating device.

[0019] In one possible implementation, the insulating conduit is a polytetrafluoroethylene tube with a diameter of 15–25 mm and a wall thickness of 1–3 mm.

[0020] In one possible implementation, the power-collecting device includes: a flame-retardant wire, a metal power-collecting plate, an insulated wire clamp, and a metal plug;

[0021] One end of the flame-retardant wire is connected to the first end of the low-voltage winding, and the other end of the flame-retardant wire is connected to the metal power-taking plate.

[0022] The metal power-generating plate is fixed to the insulated wire clamp;

[0023] The insulated wire clamp is fixed inside the transformer tank of the high-impedance transformer;

[0024] The metal plug is disposed on the metal power-generating plate and is used to fix the insulating conduit.

[0025] In one possible implementation, the flame-retardant wire is 1.5–6 mm thick. 2 Flame-retardant wires.

[0026] In one possible implementation, the metal power-generating plate is one of a brass power-generating plate, a copper power-generating plate, or a stainless steel power-generating plate.

[0027] In one possible implementation, the brass power-generating plate is a brass bracket.

[0028] Secondly, embodiments of the present invention provide a transformer winding to ground low-energy discharge defect simulation system, including the transformer winding to ground low-energy discharge defect simulation device as described in the first aspect or any possible implementation of the first aspect.

[0029] This invention provides a device and system for simulating low-energy discharge defects in transformer windings to ground. A power-taking device is connected to the beginning of the low-voltage winding of a high-impedance transformer and positioned at a predetermined distance from the beginning of the low-voltage winding. An insulating conduit is fixed to the power-taking device, and a low-energy discharge defect model placed inside the insulating conduit is in contact with the power-taking device. The model is led out of the insulating conduit and grounded via a wire. Power can be drawn from the low-voltage winding of the high-impedance transformer using the power-taking device, and the low-energy discharge defect model is sent to the power-taking device through the insulating conduit for discharge. This simulates low-energy discharge defects in the winding coil to ground without causing losses to the transformer coil, thereby improving the transformer maintenance skills and the ability to analyze and diagnose transformer faults. Furthermore, since this embodiment uses the low-voltage winding of a high-impedance transformer for power, and the high-impedance transformer can better limit short-circuit current, it can prevent the low-energy discharge defect model from being damaged by a large short-circuit current, thus extending the service life of the low-energy discharge defect model. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the transformer winding to ground low-energy discharge defect simulation device provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a high-impedance transformer provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of the low-energy discharge defect model provided in the embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the power extraction device provided in an embodiment of the present invention;

[0035] In the picture:

[0036] 10. Power extraction device; 11. Flame-retardant wire; 12. Metal power extraction plate; 13. Insulated wire clamp; 14. Metal plug; 20. High impedance transformer; 21. High voltage winding; 22. First low voltage winding; 23. Second low voltage winding; 24. Transformer core; 30. Insulated conduit; 40. Low energy discharge defect model; 41. Model skeleton; 42. Core; 43. Isolation column; 44. Copper column; 45. Coil coil; 46. Metal needle; 47. Spring; 48. Screw; 50. Wire. Detailed Implementation

[0037] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0039] like Figure 1 As shown, the transformer winding low-energy discharge defect simulation device provided in this embodiment of the invention includes: a power extraction device 10, a high-impedance transformer 20, an insulating conduit 30, a low-energy discharge defect model 40, and a conductor 50.

[0040] The power taking device 10 is connected to the first end of the low-voltage winding of the high-impedance transformer 20 and is located at a preset distance from the first end of the low-voltage winding.

[0041] The insulating conduit 30 is fixed to the power supply device 10.

[0042] The low-energy discharge defect model 40, which is set inside the insulating conduit 30, is in contact with the power extraction device 10 and is led out of the insulating conduit 30 and grounded through the wire 50.

[0043] The preset distance can be 3 to 10 cm. For example, the preset distance can be 5 cm, that is, the power extraction device 10 can be positioned 5 cm away from the beginning of the low-voltage winding of the high-impedance transformer 20. The power extraction device 10 is connected to the beginning of the low-voltage winding, that is, the power extraction device is used to extract power from the low-voltage winding of the high-impedance transformer in order to form the voltage conditions for simulating the low-energy discharge defect of the transformer winding to ground.

[0044] Then, using an implantable insulating conduit, the low-energy discharge defect model 40 is inserted into the high-impedance transformer 20 through the insulating conduit 30 and fixed on the power extraction device 10. The power extraction device 10 contacts the beginning of the low-voltage winding of the high-impedance transformer 20. Then, the end of the low-energy discharge defect model 40 is led out of the insulating conduit 30 through the wire 50 and grounded, thus forming a transformer winding to ground low-energy discharge defect simulation device.

[0045] To meet insulation requirements, the insulating conduit 30 can be a polytetrafluoroethylene (PTFE) tube with a diameter of 15–25 mm and a wall thickness of 1–3 mm. For example, a transparent PTFE tube with a diameter of 20 mm and a wall thickness of 1 mm can be used as the insulating conduit 30.

[0046] Combination Figure 1 and Figure 4 As shown, one end of the insulating conduit 30 can be fixed to the power taking device 10, specifically to the metal power taking plate 12 of the power taking device 10, and the other end can be led out of the transformer box cover.

[0047] Among them, the wire 50 that leads the low-energy discharge defect model 40 out of the insulating conduit 30 and grounds it can be a flexible metal wire.

[0048] When simulating low-energy discharge defects of transformer windings to ground using the transformer winding-to-ground low-energy discharge defect simulation device of this embodiment, the power extraction device 10 draws power from the low-voltage winding of the high-impedance transformer 20, and the low-energy discharge defect model 40 is sent to the power extraction device 10 through the insulating conduit 30 for discharge, thereby completing the simulation of low-energy discharge defects of transformer windings to ground. This allows for the simulation of low-energy discharge defects of winding coils to ground without causing losses to the transformer coils, thus helping to improve the transformer maintenance skills and the ability to analyze and diagnose transformer faults. Furthermore, since this embodiment uses the low-voltage winding of a high-impedance transformer for power extraction, and the high-impedance transformer can better limit short-circuit current, it can prevent the low-energy discharge defect model from being broken down when the short-circuit current is large, thereby increasing the service life of the low-energy discharge defect model.

[0049] Optional, combined Figure 2 As shown, the high-impedance transformer 20 is a transformer including an axial split winding 23. The power taking device 10 is connected to the first end of the axial split winding 23 and is located at a preset distance from the first end of the axial split winding 23.

[0050] High-impedance transformers refer to transformers whose short-circuit voltage percentage exceeds the percentage specified by national standards for the same voltage level and capacity. Compared to conventional transformers, high-impedance transformers have a larger short-circuit impedance, which is equivalent to increasing the positive sequence impedance of the system, thereby limiting the short-circuit current. Therefore, drawing power from the low-voltage winding of a high-impedance transformer can prevent excessive short-circuit current from causing the low-energy discharge defect model 40 to break down when the winding is short-circuited to ground, thus improving the service life of the low-energy discharge defect model 40 and the entire transformer winding-to-ground low-energy discharge defect simulation device.

[0051] Among them, combined Figure 2 As shown, the high-impedance transformer 20 includes a high-voltage winding 21, a first low-voltage winding 22, a second low-voltage winding 23, and a transformer core 24. In implementation, the high-impedance transformer 20 increases the leakage reactance of the winding by splitting the low-voltage winding into two parts, namely, splitting it into a first low-voltage winding 22 and a second low-voltage winding 23. The second low-voltage winding 23 is also known as the axially split winding.

[0052] For example, a three-phase, three-winding high-impedance transformer can be used. The rated voltage of the high-voltage winding can be 35kV, the rated voltage of the first low-voltage winding can be 400V, and the second low-voltage winding is an axially split winding. The winding uses bare copper wire and has a rated voltage of 400V.

[0053] When the high-impedance transformer 20 is a transformer including an axial split winding 23, a power taking device 10 is fixed at a preset distance on one side of the axial split winding, an insulating conduit 30 is fixed on the power taking device 10, and a point is taken from the first end of the axial split winding and connected to the power taking device 10. The low-energy discharge defect model 40 is sent to the power taking device 10 through the insulating conduit 30 for discharge, thereby achieving the effect of simulating low-energy discharge of the winding to ground.

[0054] Optional, combined Figure 3 As shown, the low-energy discharge defect model 40 may include: a model skeleton 41, an iron core 42, an isolation column 43, a copper column 44, a coil 45, a metal needle 46, a spring 47, and a screw 48.

[0055] The iron core 42 is fixedly installed at one end of the model skeleton 41, and one end of the iron core 42 is located in the cavity formed by the model skeleton 41.

[0056] The isolation column 43 is located on the other end of the iron core 42.

[0057] The copper pillar 44 is mounted on the isolation pillar 43, and the copper pillar 44 is welded to the wire 50.

[0058] The coil 45 is wound around the model skeleton 41.

[0059] The metal needle 46 is fixedly mounted at the other end of the model skeleton 41, and the metal needle 46 and the iron core 42 are connected by a spring 47.

[0060] Screw 48 is fixed below metal needle 46 by model skeleton 41, and screw 48 is in contact with power supply device 10.

[0061] Among them, the isolation column 43 can be made of insulating materials, such as polytetrafluoroethylene or polyethylene.

[0062] The low-energy discharge defect model 40 in this embodiment is designed based on the principle of electromagnetic induction. A copper post 44 at the end of the low-energy discharge defect model 40 is connected by a wire. When the screw 48 in the low-energy discharge defect model 40 is placed on the power-generating device 10, the coil 45 in the low-energy discharge defect model 40 is energized at both ends through the principle of electromagnetic induction, forming a closed loop. This attracts the spring 47, causing the metal needle 46 to collide with the screw 48, resulting in a short-circuit discharge, thereby simulating the effect of low-energy discharge from the winding to ground.

[0063] Optional, combined Figure 4 As shown, the power-generating device 10 may include: a flame-retardant wire 11, a metal power-generating plate 12, an insulated wire clamp 13, and a metal plug 14.

[0064] One end of the flame-retardant wire 11 is connected to the first end of the low-voltage winding, and the other end of the flame-retardant wire 11 is connected to the metal power take-off plate 12.

[0065] The metal power-generating plate 12 is fixed on the insulated wire clamp 13.

[0066] The insulated wire clamp 13 is fixed inside the transformer box of the high-impedance transformer 20.

[0067] Metal plug 14 is installed on metal power take-off plate 12 to fix insulating conduit 30.

[0068] The flame-retardant wire 11 can be 1.5–6 mm thick. 2 Flame-retardant wires, such as 2.5mm² 2 The flame-retardant wire. The metal power strip 12 can be one of brass, copper, or stainless steel. For example, when the metal power strip 12 is a brass power strip, a brass bracket can be used as the brass power strip.

[0069] Combination Figure 1 and Figure 4 As shown, in order to ensure the rationality of the subsequent transformer winding low-energy discharge defect simulation test, an insulated wire clamp 13 can be set on the other side of the winding inside the transformer box. Thus, based on the insulated wire clamp 13 on the other side of the winding, another transformer winding low-energy discharge defect simulation device is formed, so that the two sets of transformer winding low-energy discharge defect simulation devices on both sides of the transformer winding can serve as backups for each other.

[0070] For example, a brass bracket can be fixed to the insulated wire clamp at the first 5cm of the axial split winding using self-tapping screws, and then a 2.5mm... 2 Flame-retardant wires were soldered to the axial split winding and brass bracket using high temperature. Then, a suitable length of polytetrafluoroethylene (PTFE) tube (also known as Teflon tube) was cut, and a metal plug was fixed to the bottom of one end of the Teflon tube. The side with the metal plug was then passed through the high-impedance transformer from top to bottom and fixed to the brass bracket. Next, the copper pillars in the low-energy discharge defect model were soldered to the end of a flexible metal wire with an insulated outer sheath. The flexible metal wire carrying the low-energy discharge defect model was then passed through the Teflon tube, and the low-energy discharge defect model was placed on the metal plug in contact with the brass bracket, thus constructing a transformer winding-to-ground low-energy discharge defect simulation device.

[0071] In this embodiment of the invention, a power-taking device is connected to the beginning of the low-voltage winding of a high-impedance transformer and positioned at a predetermined distance from the beginning of the low-voltage winding. An insulating conduit is fixed to the power-taking device, and a low-energy discharge defect model placed inside the insulating conduit is in contact with the power-taking device. The model is led out of the insulating conduit and grounded via a wire. Power can be drawn from the low-voltage winding of the high-impedance transformer using the power-taking device, and the low-energy discharge defect model is sent to the power-taking device through the insulating conduit for discharge. This allows for the simulation of low-energy discharge defects from the winding coil to ground without causing losses to the transformer coil, thereby improving the transformer maintenance skills and the ability to analyze and diagnose transformer faults. Furthermore, since this embodiment utilizes the low-voltage winding of the high-impedance transformer for power drawing, and the high-impedance transformer better limits short-circuit current, it avoids the breakdown of the low-energy discharge defect model when the short-circuit current is large, thus extending the lifespan of the low-energy discharge defect model and enabling continuous use of the entire transformer winding to ground low-energy discharge defect simulation device.

[0072] As another embodiment of the present invention, the present invention may also include a transformer winding to ground low energy discharge defect simulation system, including the transformer winding to ground low energy discharge defect simulation device as described in any of the above embodiments, and having the same beneficial effects as the above-described transformer winding to ground low energy discharge defect simulation device, which will not be described again here.

[0073] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0074] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A low energy partial discharge to ground fault simulation device for a transformer winding, characterized by, include: Power extraction device, high-impedance transformer, insulated conduit, low-energy discharge defect model and wire; The power extraction device is connected to the first end of the low-voltage winding of the high-impedance transformer and is located at a predetermined distance from the first end of the low-voltage winding. The insulating conduit is fixed to the power supply device; The low-energy discharge defect model disposed inside the insulating conduit is in contact with the power extraction device, and is led out of the insulating conduit and grounded through the wire; The low-energy discharge defect model includes: a model skeleton, an iron core, coils, an isolation pillar, metal needles, springs, screws, and copper pillars; The iron core is fixedly disposed at one end of the model skeleton, and one end of the iron core is located in the cavity formed by the model skeleton; The isolation column is disposed at the other end of the iron core; The copper pillar is disposed on the isolation pillar, and the copper pillar is welded to the wire; The coil is wound around the perimeter of the model skeleton; The metal needle is fixedly disposed at the other end of the model skeleton, and the metal needle and the iron core are connected by the spring; The screw is fixed below the metal needle by the model skeleton, and the screw is in contact with the power-generating device.

2. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 1, characterized in that, The high-impedance transformer is a transformer that includes an axially split winding, and the low-voltage winding is the axially split winding.

3. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 1 or 2, characterized in that, The preset distance is 3~10cm.

4. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 1, characterized in that, The insulating conduit is a polytetrafluoroethylene tube with a diameter of 15-25 mm and a wall thickness of 1-3 mm.

5. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 1, characterized in that, The power extraction device includes: a flame-retardant wire, a metal power extraction plate, an insulated wire clamp, and a metal plug; One end of the flame-retardant wire is connected to the first end of the low-voltage winding, and the other end of the flame-retardant wire is connected to the metal power-taking plate. The metal power-generating plate is fixed to the insulated wire clamp; The insulated wire clamp is fixed inside the transformer tank of the high-impedance transformer; The metal plug is disposed on the metal power-generating plate and is used to fix the insulating conduit.

6. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 5, characterized in that, The flame-retardant wire is 1.5-6 mm 2 of flame-retardant wire.

7. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 5, characterized in that, The metal power-generating plate is one of brass power-generating plate, copper power-generating plate, or stainless steel power-generating plate.

8. The transformer winding-to-ground low-energy discharge defect simulation device according to claim 7, characterized in that, The brass power-generating board is a brass bracket.

9. A transformer winding-to-ground low-energy discharge defect simulation system, characterized in that, Includes the transformer winding to ground low energy discharge defect simulation device as described in any one of claims 1-8.

Images