Replaceable insulation defect simulation method
By dividing the dry-type transformer winding into a detachable first section and a second section and setting multiple insulation defects, the problem of inaccurate simulation in the prior art is solved, and high-fidelity discharge characteristic simulation and fault detection are achieved.
Patent Information
- Application Number
- CN202510827109.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-19
- Publication Date
- 2025-09-26
AI Technical Summary
Existing technology makes it difficult to produce a dry-type transformer insulation defect model in the laboratory that is consistent with actual engineering applications, resulting in inaccurate simulation of discharge characteristics and a single defect type that cannot truly reflect the actual fault situation.
Each phase winding of the dry-type transformer is set as a detachable first-section winding and a second-section winding. Multiple first-section windings with different insulation defects are set up to form a three-phase winding by assembly to simulate a variety of actual defects. An EI-type iron core structure is used to achieve high-fidelity simulation.
It achieves high-fidelity simulation of the discharge characteristics of dry-type transformers, can truly reflect the insulation defects in actual engineering applications, and supports the detection and rapid early warning of partial discharge in transformers.
Smart Images
Figure CN120703530A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of dry-type transformers, and in particular to a replaceable insulation defect simulation method. Background Art
[0002] Dry-type transformers are widely used in low-voltage power distribution systems due to their compact size, high safety, and environmentally friendly features. Unlike oil-immersed transformers, their structures and failure mechanisms differ significantly. Dry-type transformers are difficult to self-recover from insulation failures, and since distribution networks directly serve users, a dry-type transformer failure can have severe consequences. During normal operation, the internal insulation of a transformer is subjected to high electric field strengths for extended periods, making partial discharge (PD) prone to occur in areas with weak insulation. The long-term presence of PD can irreversibly damage the transformer's insulation material and pose a significant risk. Therefore, PD monitoring of transformers is essential to promptly and effectively identify potential internal faults or hidden dangers and prevent accidents.
[0003] Currently, laboratory research on transformer partial discharge characteristics primarily focuses on small models of insulation defects, such as pin-plate discharge models and suspended discharge models. First, the discharge characteristics of the insulation defect models (model only) are studied. Second, small models of insulation defects are installed at the high-voltage lead-out bolts of the windings to explore the discharge characteristics of different insulation defects under different transformer operating conditions. However, laboratory insulation defect models have low size, structure, and environmental equivalence, differ significantly from actual transformer defects, and the defect location is limited (often located at the high-voltage lead-out bolts of the transformer windings), making it difficult to replicate the discharge characteristics of transformers in actual engineering applications. Designing insulation defect models that closely resemble actual engineering practices can achieve high-fidelity simulation of transformer discharge characteristics and, based on these discharge characteristics, enable detection and rapid early warning of transformer partial discharge. Therefore, fabricating physical transformers with different insulation defects and studying their actual discharge characteristics is crucial for transformer partial discharge detection. Existing technologies primarily involve directly creating pre-set faults in the physical transformer or installing fault simulation devices externally. The former approach is difficult to modify, simulates a limited number of defects, and is therefore less practical. The latter, however, is affected by the installation location and cannot capture the discharge characteristics of internal transformer defects. Summary of the Invention
[0004] The purpose of the present invention is to provide a replaceable insulation defect simulation method to achieve high-fidelity simulation of the discharge characteristics of a dry-type transformer.
[0005] To achieve the above object, the present invention provides a replaceable insulation defect simulation method, comprising:
[0006] Each phase winding of the dry-type transformer is configured to be detachably mounted with a first winding section and a second winding section; the first winding section is close to the upper iron yoke, and the second winding section is used to be mounted at a transformer position close to the lower iron yoke;
[0007] providing a plurality of first winding sections containing different insulation defects and a first winding section containing no insulation defects;
[0008] According to the insulation defect to be simulated, several first-segment windings containing or not containing the insulation defect to be simulated are selected, and the first-segment windings are assembled with three second-segment windings to obtain the three-phase winding of the dry-type transformer;
[0009] The insulation defect simulation is performed on the three-phase winding of the assembled dry-type transformer with the insulation defect to be simulated.
[0010] Preferably, the iron core of the three-phase winding of the dry-type transformer adopts an EI type structure.
[0011] Preferably, the insulation defects to be simulated include single-phase winding defects and multi-phase winding defects.
[0012] Preferably, the different insulation defects include tip defects, floating potential defects and surface defects.
[0013] Preferably, the tip defect is a sharp metal conductor implanted in the gap between the first section of the winding coils or the insulation interface between turns, and the curvature radius of the metal conductor is ≤0.5 mm.
[0014] Preferably, the floating potential defect includes multi-point suspension of the iron core and tapped coil suspension; the multi-point suspension of the iron core is to set at least 3 ground insulation points at the position of the iron core column or iron yoke close to the winding; the tapped coil suspension is to add a non-functional winding near the winding, and the head and end of the non-functional winding are connected through an RC network; the number of turns of the non-functional winding is 5-10 turns, and the R of the RC network is 1~10MΩ, and C is 50~200pF.
[0015] Preferably, the surface defect is a continuous conductive path with a width of 2-5 mm constructed on the cast epoxy resin surface of the winding using silver epoxy resin.
[0016] The present invention has the following beneficial effects:
[0017] The present invention configures each phase winding of a dry-type transformer into a detachable first winding section and a second winding section, and provides multiple first winding sections with different insulation defects. This allows simulation of various insulation defects that may occur in actual engineering projects. Compared with the low size, structure, and environmental equivalence of insulation defect models in the laboratory, the physical transformer produced by this method can more realistically reflect the discharge characteristics of the transformer under actual engineering applications, achieving high-fidelity simulation of the transformer discharge characteristics. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0019] Figure 1 This is a flow chart of a replaceable insulation defect simulation method according to an embodiment of the present invention.
[0020] Figure 2 Schematic diagram of the structure of the segmented winding in an embodiment of the present invention.
[0021] Figure 3 Schematic diagram of the structure of the EI type iron core in an embodiment of the present invention.
[0022] Figure 4 This is a schematic diagram of the insulation defect setting principle in an embodiment of the present invention. DETAILED DESCRIPTION
[0023] The detailed description of the accompanying drawings is intended as an illustration of the current embodiment of the present invention and is not intended to represent the only form in which the present invention can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be included in the spirit and scope of the present invention.
[0024] An embodiment of the present invention provides a replaceable insulation defect simulation method, comprising the following steps:
[0025] Step S10, arranging each phase winding of the dry-type transformer into a detachably mounted first winding section and a second winding section; the first winding section is close to the upper iron yoke, and the second winding section is used to be installed in a transformer position close to the lower iron yoke;
[0026] Step S20, setting a plurality of first winding sections containing different insulation defects and a first winding section containing no insulation defects;
[0027] Step S30, selecting a plurality of first winding sections containing or not containing the insulation defect to be simulated according to the insulation defect to be simulated, and assembling them with three second winding sections to obtain a three-phase winding of a dry-type transformer;
[0028] Step S40 , performing insulation defect simulation on the assembled three-phase winding of the dry-type transformer with the insulation defect to be simulated.
[0029] Specifically, the three-phase windings ABC are cast in two sections, namely the first section and the second section. In these two section windings, the first section near the upper iron yoke is selected to set the insulation defect to facilitate the replacement of the winding model. For the structure of the defective section winding, multiple section windings with different insulation defects are set. According to the simulated insulation defects, the corresponding defective section winding module is replaced, such as Figure 2 As shown in the figure, if you want to simulate the influence of different spatial positions of defects on the discharge propagation characteristics, you can set it to a multi-segment winding casting method, such as three segments, and set insulation defects inside the upper, middle and lower segment windings respectively.
[0030] Preferably, the iron core of the three-phase winding of the dry-type transformer adopts an EI type structure.
[0031] Specifically, the commonly used iron core stacking structure is a bevel joint, but in order to achieve the detachable and easy replacement of the segmented winding, this embodiment uses an EI type structure, using E-shaped and I-shaped silicon steel sheets to stack and press the iron core. At the same time, the structure is simple, easy to stamp and form, and the processing cost is low. The EI type iron core structure is as follows: Figure 3 shown.
[0032] Preferably, the insulation defects to be simulated include single-phase winding defects and multi-phase winding defects.
[0033] Specifically, when performing a single defect simulation, a defect is selected from the aforementioned typical defect models and cast into the segmented winding 1. The segmented winding 1 of phase A is replaced with a segmented winding containing a defect. It is necessary to study the influence of the defect position on the defect local discharge characteristics. The defective segmented windings can be placed in phases B and C respectively.
[0034] When simulating a composite defect, select two or more defects from the aforementioned typical defect models and cast them into segmented winding 1. Replace segmented winding 1 on phase A with a defective segmented winding. To study the effect of defect location on the partial discharge characteristics of the defect, place the defective segmented windings on phases B and C, respectively.
[0035] Single-phase winding defect simulation: The defective segmented winding is only in one phase (phase A / phase B / phase C).
[0036] Multi-phase winding defect simulation: Segmented winding with defects in two phases / three phases (A+B phase / A+C phase / B+C phase / A+B+C phase).
[0037] There are 7 defect combinations and 7 phase position combinations of defective segmented windings, which can ultimately form 7×7=49 differentiated defect simulation schemes.
[0038] Preferably, if Figure 4 As shown, the different insulation defects include tip defects, floating potential defects and surface defects.
[0039] Preferably, if Figure 4 As shown, the tip defect is a sharp metal conductor implanted in the gap between the first section of the winding coil or the insulation interface between turns, and the curvature radius of the metal conductor is ≤0.5mm, simulating wire burrs or process residues.
[0040] Preferably, if Figure 4 As shown, the floating potential defects include multi-point suspension of the core and tapped coil suspension; the multi-point suspension of the core is to set at least three ground insulation points (insulation resistance ≥ 10GΩ) at the position of the core column or iron yoke near the winding; the tapped coil suspension is to add a non-functional winding near the winding, and the head and end of the non-functional winding are connected by an RC network; the number of turns of the non-functional winding is 5-10 turns, and the R of the RC network is 1-10MΩ, C = 50-200pF; particle contamination: metal particles with a diameter of 1mm (Cu / Al, surface density 0.5-2 pieces / cm) are implanted in the winding pad / epoxy resin 2 ).
[0041] Preferably, if Figure 4 As shown, the surface defect is a continuous conductive path with a width of 2-5 mm constructed on the epoxy resin surface of the winding using silver epoxy resin (such as silver conductive glue, with a volume conductivity of 102-104 S / m).
[0042] While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A replaceable insulation defect simulation method, characterized in that: include: Each phase winding of the dry-type transformer is arranged into a detachably mounted first winding section and a second winding section; The first section of the winding is close to the upper iron yoke, and the second section of the winding is used to be installed in a transformer position close to the lower iron yoke; providing a plurality of first winding sections containing different insulation defects and a first winding section containing no insulation defects; According to the insulation defect to be simulated, several first-segment windings containing or not containing the insulation defect to be simulated are selected, and the first-segment windings are assembled with three second-segment windings to obtain the three-phase winding of the dry-type transformer; The insulation defect simulation is performed on the three-phase winding of the assembled dry-type transformer with the insulation defect to be simulated.
2. The method according to claim 1, characterized in that The core of the three-phase winding of the dry-type transformer adopts EI type structure.
3. The method according to claim 1, characterized in that The insulation defects to be simulated include single-phase winding defects and multi-phase winding defects.
4. The method according to claim 1, wherein The different insulation defects include tip defects, floating potential defects and surface defects.
5. The method according to claim 4, characterized in that The tip defect is a sharp metal conductor implanted in the gap between the first section of the winding coil or the insulation interface between turns, and the curvature radius of the metal conductor is ≤0.5mm.
6. The method according to claim 4, characterized in that The floating potential defects include multi-point suspension of the iron core and suspension of the tapped coil; the multi-point suspension of the iron core is to set at least three ground insulation points at the position of the iron core column or iron yoke near the winding; the tapped coil suspension is to add a non-functional winding near the winding, and the head and end of the non-functional winding are connected through an RC network; the number of turns of the non-functional winding is 5-10 turns, and the R of the RC network is 1~10MΩ, and C is 50~200pF.
7. The method according to claim 4, characterized in that The surface defect is a continuous conductive path with a width of 2-5 mm constructed on the cast epoxy resin surface of the winding using silver epoxy resin.