Electrode device and system for simulating discharge of transformer winding coil and discharge detection method

Abstract

The invention relates to the technical field of transformers, in particular to an electrode device and system for simulating discharge of a transformer winding coil and a discharge detection method. Comprising a high-voltage conductor as a discharging high-voltage end; the low-voltage conductor is used as a discharging low-voltage end and is spaced from the high-voltage conductor to form a discharging gap; the insulating supporting piece is used for accommodating and supporting the high-voltage conductor and the low-voltage conductor and is filled with an insulating medium; and the lead is connected to the high-voltage conductor and is led out of the transformer. The typical defect discharge phenomenon in the winding coil can be reproduced in a real oil immersion environment, and the characteristic rule and the development process of the discharge signal in the coil can be reflected.

Description

Technical Field

[0001] This application relates to the field of transformer technology, specifically to an electrode device, system, and discharge detection method for simulating transformer winding coil discharge. Background Technology

[0002] Transformers are core equipment in substations, their main function being voltage transformation. They play a crucial role in reducing power transmission losses and enabling cross-regional power distribution. The operational reliability of transformers directly affects the stability of the power grid in the region. Discharges caused by defects such as foreign objects and insulation damage inside the transformer windings will accelerate the deterioration of the transformer winding insulation, ultimately leading to transformer explosions and causing huge economic losses and social impacts. Therefore, conducting simulation experiments on internal discharges in transformer windings is of great significance.

[0003] Transformer winding coils are critical components of a transformer. Discharge within the coils can damage the inter-turn insulation structure and even cause irreversible damage to the entire transformer, resulting in significant difficulties, long recovery times, and high costs. Currently, simulation tests of internal transformer discharges have only been conducted on low-voltage transformers or large metal tanks. Partial discharges generated within the coils have not yet been simulated on full-scale transformers.

[0004] Therefore, the existing simulation test systems and methods have poor equivalence and cannot reflect the characteristic laws and development process of the discharge signal inside the coil. Summary of the Invention

[0005] In view of this, the present application provides an electrode device, system and discharge detection method for simulating transformer winding coil discharge, so as to solve the problem that the existing simulation test system and method have poor equivalence and cannot reflect the characteristic law and development process of the discharge signal inside the coil.

[0006] A first aspect of this application provides an electrode device for simulating transformer winding coil discharge, which is disposed inside a transformer and includes: High-voltage conductor, serving as the high-voltage end for discharge; The low-voltage conductor, serving as the low-voltage end of the discharge, is spaced apart from the high-voltage conductor to form a discharge gap; An insulating support member that houses and supports the high-voltage conductor and the low-voltage conductor, and whose interior is filled with an insulating medium; Lead wires are connected to the high-voltage conductor and used to lead out to the outside of the transformer.

[0007] In one embodiment, the insulating support is a sealed structure, and the wall surface of the insulating support has an injection hole that connects the inside and outside.

[0008] In one embodiment, the high-voltage conductor is fixed inside one end of the insulating support, and the low-voltage conductor is fixed inside the other end of the insulating support. The ends of the high-voltage conductor and the low-voltage conductor are arranged opposite to each other and form a discharge gap.

[0009] In one embodiment, the insulating support is made of an insulating material and has a transparent structure.

[0010] A second aspect of this application provides a system for simulating transformer winding coil discharge, comprising: The electrode device provided in the first aspect of the embodiments of this application; A pressurizing device is used to connect to one end of the high-voltage bushing of the electrode device and the transformer to apply voltage to the electrode device and the high-voltage bushing; A detection device is used to connect to the other end of the high-voltage bushing to detect partial discharge signals.

[0011] In one embodiment, the top of the transformer tank is provided with an electrode sleeve, one end of which is used to connect to the high-voltage output terminal of the pressurizing device, and the other end is used to connect to the lead wire of the electrode device.

[0012] In one embodiment, the electrode device is disposed in the oil passage between the high-voltage coil and the voltage regulating coil of the transformer, and is located in the area near the top or bottom of the oil tank.

[0013] In one embodiment, the detection device includes a detection impedance sensor and a partial discharge detection device, wherein the output terminal of the detection impedance sensor is used to connect to the partial discharge detection device, and the input terminal is used to connect to the other end of the high-voltage bushing.

[0014] In one embodiment, the pressurizing device is a power frequency pressurizing device or a series resonant pressurizing device.

[0015] A third aspect of this application provides a discharge detection method based on the system of the second aspect of this application, comprising: Install the electrode device inside the transformer, connect the high voltage output terminal of the pressurizing device to one end of the high voltage bushing of the transformer and the electrode device, and connect the other end of the high voltage bushing to the detection device. The pressurization device outputs voltage to perform partial discharge detection.

[0016] The first aspect of this application provides an electrode device for simulating transformer winding coil discharge, which is installed inside a transformer and includes: a high-voltage conductor as the high-voltage end of the discharge; a low-voltage conductor as the low-voltage end of the discharge, spaced apart from the high-voltage conductor to form a discharge gap; an insulating support member that accommodates and supports the high-voltage conductor and the low-voltage conductor, and is internally filled with an insulating medium; and leads connected to the high-voltage conductor and used to lead out to the outside of the transformer. By setting a controllable discharge gap between the spaced high-voltage and low-voltage conductors inside the transformer, the discharge phenomenon of typical defects inside the winding coil can be reproduced in a real oil-immersed environment, reflecting the characteristic laws and development process of the discharge signal inside the coil. The insulating support member provides stable physical isolation to ensure the discharge space morphology, and the lead-out design enables external signal access and voltage loading, providing a foundation for subsequent accurate detection. The overall structure is compact and adaptable to the internal space constraints of the transformer. This helps to study the characteristic laws and development process of discharge inside the transformer winding coil, explore detection methods suitable for this type of discharge, detect and eliminate potential hazards in advance, and ensure the safe operation of transformer equipment.

[0017] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an electrode device for simulating transformer winding coil discharge provided in an embodiment of this application; Figure 2 This is a schematic diagram of the installation position of the electrode device provided in one embodiment of this application; Figure 3 yes Figure 2 Top view; Figure 4 This is a schematic diagram of the connection of the electrode system for simulating transformer winding coil discharge according to an embodiment of this application. Detailed Implementation

[0020] 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 this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0024] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0025] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0026] like Figure 1As shown in the embodiment of this application, 1. An electrode device for simulating transformer winding coil discharge, characterized in that it is used to be disposed inside the transformer and includes: High-voltage conductor 13 serves as the high-voltage end for discharge; The low-voltage conductor 12, serving as the low-voltage end of the discharge, is spaced apart from the high-voltage conductor 13 to form a discharge gap. An insulating support 11 accommodates and supports the high-voltage conductor 13 and the low-voltage conductor 12, and its interior is filled with an insulating medium. Lead 14 is connected to the high-voltage conductor 13 and is used to lead out to the outside of the transformer.

[0027] This application's embodiments, by establishing a controllable discharge gap between high-voltage and low-voltage conductors within the transformer, can reproduce typical defect discharge phenomena within the winding coil in a real oil-immersed environment, reflecting the characteristic patterns and development processes of the discharge signals inside the coil. The insulating support provides stable physical isolation to ensure the discharge space morphology, while the lead-out design enables external signal access and voltage loading, providing a foundation for subsequent accurate detection. The overall structure is compact and adaptable to the internal space constraints of the transformer. This facilitates the study of the characteristic patterns and development processes of discharges within the transformer winding coil, explores detection methods suitable for such discharges, identifies and eliminates potential hazards in advance, and ensures the safe operation of transformer equipment.

[0028] In one embodiment, the insulating support 11 is a sealing structure, and the wall surface of the insulating support 11 is provided with an injection hole that connects the inside and outside.

[0029] The insulating support component in this application adopts a sealed structure to prevent the intrusion of external impurities. The wall injection hole design achieves a dual function: balancing the internal and external air pressure during the transformer vacuuming stage to avoid structural damage, and ensuring that the insulating oil fully penetrates and fills the interior of the support component during the oil injection stage, so that the discharge gap dielectric environment is completely equivalent to the actual winding fault condition, significantly improving the simulation realism.

[0030] In one embodiment, the high-voltage conductor 13 is fixed inside one end of the insulating support member 11, and the low-voltage conductor 12 is fixed inside the other end of the insulating support member 11. The ends of the high-voltage conductor 13 and the low-voltage conductor 12 are arranged opposite to each other and form a discharge gap.

[0031] In this embodiment, the high-voltage conductor and the low-voltage conductor are respectively fixed at both ends of the insulating support and their ends are opposite to each other, forming an axially aligned discharge gap structure. This arrangement concentrates the electric field between the ends of the conductors, accurately simulating the local strong electric field discharge mode caused by short circuit between winding turns or foreign objects. The discharge physical process is highly consistent with the real fault.

[0032] In one embodiment, the insulating support 11 is made of an insulating material and has a transparent structure.

[0033] In this application, both the high-voltage and low-voltage conductors utilize metallic needle tips as the high-voltage and low-voltage ends for discharge. The insulating support is a glass tube made of acrylic material, serving as the support for both the high-voltage and low-voltage conductors. A small circular hole is drilled on the side of the glass tube to maintain consistent air pressure inside and outside the tube, preventing damage from transformer vacuuming. Additionally, during transformer oil filling, the hole allows transformer oil to seep into and fill the glass tube, acting as the insulating medium between the high-voltage and low-voltage conductors. Armored cables are used as leads, with one end connected to the high-voltage conductor and the other end extending to the outside of the transformer casing for pressurized partial discharge detection tests.

[0034] In this application, the high-voltage conductor is connected and led out to the top of the transformer tank via an armored cable. A hole is drilled at a suitable location on the top of the transformer to install a small electrode bushing 3. The electrode bushing 3 can be a 12kV or 40.5kV bushing. The top of the bushing is connected to the armored cable, and the conductor at the top of the bushing is used to connect the pressurization equipment.

[0035] like Figures 2-4 As shown, this application provides a system for simulating transformer winding coil discharge, comprising: Electrode device 1 as described above; The pressurizing device 6 is used to connect to one end of the high-voltage bushing 7 of the electrode device 1 and the transformer to apply voltage to the electrode device 1 and the high-voltage bushing 7. A detection device is used to connect to the other end of the high-voltage bushing 7 to detect partial discharge signals.

[0036] The system-integrated electrode device, pressurizing device, and detection device in this application embodiment form a closed-loop verification chain: the pressurizing device synchronously loads the transformer high-voltage bushing and the electrode device, so that the discharge behavior of the implanted electrode is always in the real winding operating electric field environment; the detection device captures the mixed signal through the high-voltage bushing end screen to realize the synchronous analysis of background noise and simulated discharge.

[0037] In one embodiment, the top 21 of the transformer tank is provided with an electrode sleeve 3. One end of the electrode sleeve 3 is used to connect to the high voltage output terminal of the pressurizing device 6, and the other end is used to connect to the lead wire 14 of the electrode device 1.

[0038] The transformer tank top electrode bushing design of this application provides a standardized interface, which not only ensures the high voltage insulation strength of the lead wires, but also avoids the loss of mechanical strength caused by opening holes in the tank; the bushing parameters match the voltage level of conventional testing equipment, significantly reducing the complexity of on-site modification.

[0039] In one embodiment, such as Figure 2As shown, the electrode device 1 is used to be installed in the oil passage 13 between the high-voltage coil 25 and the voltage regulating coil 26 of the transformer, and is located in the area near the top 21 or bottom 22 of the oil tank.

[0040] In application, taking the domestic DFP-240000 / 500 model transformer as an example, the outer winding coils of the transformer core column are distributed from the inside out as follows: low-voltage coil 24, high-voltage coil 25, and voltage regulating coil 26. The discharge electrode can be installed in the oil passage outside the high-voltage coil and inside the voltage regulating coil. The installation depth and relative angle can be adjusted according to the needs of experimental research, and electrodes can be installed at multiple points simultaneously for comparative analysis.

[0041] The electrode device in this embodiment is located in the oil channel area between the high-voltage coil and the voltage regulating coil. This location is in the high electric field gradient region of the transformer and the oil flow velocity is stable. It can accurately reflect the main insulation discharge characteristics of the winding and avoid the interference of oil pump disturbance on the discharge signal acquisition.

[0042] In one embodiment, the detection device includes a detection impedance sensor 4 and a partial discharge detection device 5 (i.e., a partial discharge detector). The output terminal of the detection impedance sensor 4 is used to connect to the partial discharge detection device 5, and the input terminal is used to connect to the other end of the high-voltage bushing 7.

[0043] In the application, the high-voltage output terminal of the pressurizing device is connected to the top of the high-voltage bushing of the transformer. Then, a wire is led from the top of the high-voltage bushing of the transformer to the electrode bushing. The detection impedance sensor 4 is installed at the end screen 31 of the high-voltage bushing of the transformer. One end of the detection impedance sensor 4 is grounded to ensure that the end screen 31 of the high-voltage bushing is reliably grounded. The other end is connected to the partial discharge detector, and the traditional pulse current method is used to carry out partial discharge detection.

[0044] In applications, ultra-high frequency, high frequency, and ultrasonic methods can be used simultaneously for auxiliary detection to explore the optimal detection method for this type of discharge signal.

[0045] The combination of the detection impedance sensor and the partial discharge detection device in this embodiment adopts the end-screen grounding detection path and directly couples the end-screen signal of the high-voltage bushing; this method effectively avoids the influence of the winding transfer function on the discharge waveform and ensures the fidelity of the original signal.

[0046] In one embodiment, the pressurizing device 6 is a power frequency pressurizing device 6 or a series resonant pressurizing device 6.

[0047] This application's embodiments cover different test scenario requirements through two pressurization modes: power frequency pressurization and series resonance. The power frequency mode is suitable for rapid testing of small-capacity transformers, while the resonance mode solves the reactive power compensation problem of large-capacity transformers, ensuring that the discharge process is continuous, stable, and controllable.

[0048] This application provides a discharge detection method based on the system described above, including: Install electrode device 1 inside the transformer, connect the high voltage output terminal of pressurizing device 6 to electrode device 1 and one end of high voltage bushing 7 of transformer, and connect the other end of high voltage bushing 7 to detection device. The pressurizing device 6 outputs voltage to perform partial discharge detection.

[0049] In application, a stepped voltage increase method can be used for pressurization. After the pressurization device is closed, pressurization is applied in steps of 1kV with a time interval of 2 minutes, and the partial discharge situation is observed using a partial discharge detector. When the initial discharge occurs, the pressurization time interval can be extended to 5 minutes, while the step size remains unchanged at 1kV, until a sustained discharge of about 1000pC is generated. Then, pressurization is stopped, and the detection response of the ultra-high frequency method, high frequency method, and ultrasonic method is observed.

[0050] Then, based on the time of partial discharge generation and development detected by the pulse current method, the time sequence of discharge signals detected by the ultra-high frequency method, high frequency method and ultrasonic method is compared and analyzed. The amplitude, phase distribution and spectrum characteristics of the signals detected by the three methods are further compared and analyzed, and the best detection method for internal discharge of transformer winding coils is summarized.

[0051] This application embodiment uses a parallel pressurization strategy of electrode device and high-voltage bushing to simultaneously obtain real winding background noise and simulated discharge characteristics in a single test; direct comparative analysis can eliminate inherent interference of the system and accurately extract internal discharge fingerprint parameters of the winding.

[0052] This application proposes for the first time a method of implanting discharge electrodes inside the transformer winding coil to simulate internal discharge of the transformer winding coil. The aim is to reproduce the discharge process caused by defects such as foreign objects, insulation damage, and inter-turn short circuits inside the transformer winding coil, study the characteristics and development law of internal discharge of the transformer winding coil, propose and verify a detection method suitable for internal discharge of transformer winding coil, promptly detect and eliminate hidden dangers, and ensure the safe operation of transformer equipment.

[0053] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0054] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 this application, and should all be included within the protection scope of this application.

Claims

1. An electrode device for simulating a transformer winding coil discharge, characterized by, A high-voltage electrode device for being arranged in a transformer, comprising: a high-voltage conductor (13) as a high-voltage end of discharge; a low-voltage conductor (12) as a low-voltage end of discharge, arranged in a spaced-apart manner with the high-voltage conductor (13) to form a discharge gap; an insulating support (11) for accommodating and supporting the high-voltage conductor (13) and the low-voltage conductor (12), and internally filled with an insulating medium; a lead wire (14) connected to the high-voltage conductor (13) and used for leading out to the outside of the transformer.

2. The electrode apparatus for discharging the winding coil of the analog transformer as claimed in claim 1, wherein The insulating support (11) is a sealed structure, and a wall surface of the insulating support (11) is provided with an injection hole for communication between the inside and the outside.

3. The electrode apparatus for discharging the winding coil of the analog transformer as claimed in claim 1, wherein The high-voltage conductor (13) is fixedly arranged at one end inside the insulating support (11), and the low-voltage conductor (12) is fixedly arranged at the other end inside the insulating support (11), and the end portions of the high-voltage conductor (13) and the low-voltage conductor (12) are arranged in a spaced-apart manner to form a discharge gap.

4. The electrode apparatus for discharging the winding coil of the analog transformer as recited in claim 1, wherein The insulating support (11) is made of an insulating material and is transparent.

5. A system for simulating a discharge of a transformer winding coil, characterized by An electrode device (1) according to any one of claims 1-4; a pressurizing device (6) for being connected to one end of the electrode device (1) and a high-voltage bushing (7) of a transformer to apply a voltage to the electrode device (1) and the high-voltage bushing (7); a detection device for being connected to the other end of the high-voltage bushing (7) to detect a partial discharge signal. The top (21) of an oil tank of the transformer is provided with an electrode bushing (3), one end of the electrode bushing (3) is used for connecting a high-voltage output end of the pressurizing device (6), and the other end is used for connecting the lead wire (14) of the electrode device (1).

6. The system of claim 5, wherein, The electrode device (1) is arranged in an oil channel (13) between a high-voltage coil (25) and a voltage regulating coil (26) of the transformer, and is located in a region close to the top (21) of the oil tank or the bottom (22) of the oil tank.

7. The system of claim 5, wherein, The detection device comprises a detection impedance sensor (4) and a partial discharge detection device (5), an output end of the detection impedance sensor (4) is used for connecting the partial discharge detection device (5), and an input end is used for connecting the other end of the high-voltage bushing (7).

8. The system of claim 5, wherein, The pressurizing device (6) is a power frequency pressurizing device (6) or a series resonant pressurizing device (6).

9. The system of claim 5, wherein, An electrode device (1) is installed in a transformer, a high-voltage output end of a pressurizing device (6) is connected to the electrode device (1) and one end of a high-voltage bushing (7) of the transformer, and the other end of the high-voltage bushing (7) is connected to a detection device; 10. A discharge detection method based on the system according to any one of claims 5 to 9, characterized by, The pressurizing device (6) outputs a voltage for partial discharge detection. ​ ​

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