Power transformer winding radial deformation judgment method and system, medium and product

Abstract

The invention discloses a power transformer winding radial deformation judgment method and system, a medium and a product, and relates to the field of power transformers, and the method comprises the steps: carrying out a low-voltage short-circuit reactance test between power transformer winding pairs, and obtaining the short-circuit reactance between each phase of winding pair; according to the short-circuit reactance between the winding pairs of each phase and the historical short-circuit reactance between the winding pairs of each phase, the change rate of the short-circuit reactance between the winding pairs of each phase is obtained; directly measuring the capacitance between each phase of winding pair of the power transformer by adopting a bridge positive wiring method; based on the historical capacitance, the capacitance change rate between the winding pairs of each phase is determined; determining a winding deformation result according to the short-circuit reactance change rate between each phase of winding pair and the capacitance change rate between each phase of winding pair; determining the winding deformation degree according to the short-circuit reactance change rate and the short-circuit reactance threshold value between each phase of winding pair and the winding deformation result; the deformation and the deformation degree of the power transformer winding can be accurately judged.

Description

Technical Field

[0001] This application relates to the field of power transformers, and in particular to a method, system, medium, and product for judging radial deformation of power transformer windings. Background Technology

[0002] With the development of the national economy, electricity is accounting for an increasingly larger share of final energy consumption, and the whole society is placing higher demands on reliable power supply. As one of the core elements of the power supply chain, the reliable operation of power transformers directly affects whether power grid companies can reliably supply power to society. According to relevant research statistics, winding deformation remains the primary factor leading to power transformer outages. Therefore, the National Energy Administration, State Grid Corporation of China, and China Southern Power Grid Company have all prioritized preventing power transformers from suffering cumulative short-circuit impact damage as a key anti-accident technical measure. However, in actual implementation, using existing judgment methods, there are still situations where it is impossible to accurately determine whether the power transformer windings are deformed and the degree of deformation.

[0003] Currently, there are several methods to determine whether the radial winding of a power transformer is deformed: (1) Winding frequency response method: The basic principle is to treat the power transformer as a two-port network, inject a frequency conversion voltage signal from one side of the break, and receive the output voltage signal from the other port. The ratio of the amplitude of the output signal to the input signal is used as the vertical axis, and the frequency of the injected voltage signal is used as the horizontal axis. By comparing the curves of different periods between phases or in the same phase, it can be determined whether a deformation phenomenon has occurred. GB / T 1094.18-2016 Power Transformers Part 18: Frequency Response Measurement specifies the testing procedures and analyzes some typical deformation spectrum characteristics. The power industry recommended standard DL / T 911-2016 Frequency Response Analysis Method for Winding Deformation of Power Transformers divides the frequency response bands, and proposes a method to judge the degree of deformation using correlation coefficients for different deformation modes corresponding to the low frequency band (1kHz~100kHz), mid frequency band (100kHz~600kHz), and high frequency band (>600kHz). However, the results do not have practical physical meaning, and in practical applications, the test results are easily affected by the external electromagnetic environment and wiring method. Therefore, it is not possible to judge that the winding has been deformed simply because there is a large difference in the frequency response curve. (2) Low-voltage short-circuit reactance method: The basic principle of the low-voltage short-circuit reactance method is that the short-circuit reactance between a pair of transformer windings is determined by the geometric dimensions between the windings. These geometric dimensions do not change with the test voltage. Therefore, the short-circuit reactance under low voltage can be compared with the short-circuit reactance under rated short-circuit voltage to determine whether the winding has deformed. Among them, "DL / T 1093-2018 Guidelines for the Detection and Judgment of Winding Deformation of Power Transformers by Reactance Method" proposes to use the rate of change of short-circuit reactance to determine whether the winding has deformed, but it still does not solve the problem of judging the degree of winding deformation.

[0004] The shortcomings of existing methods are mainly reflected in the following three aspects: First, when power engineering technicians conduct capacity tests on power transformers, they all base their tests on GB 50150 "Standard for Acceptance Testing of Electrical Equipment in Electrical Installation Engineering" and DL / T 473.3 "Implementation Guidelines for On-site Insulation Tests: Dielectric Loss Factor tanδ Test". The capacity test results are the capacitance between the tested winding and its adjacent windings, as well as between the core and clamps, not the capacitance between the two windings that is of most concern in judging the radial deformation of the winding. This results in the test data being insensitive to the degree of deformation. Second, neither national nor industry standards have provided explanations for judging the degree of winding deformation, resulting in inconsistent standards for judging the degree of winding deformation and a lack of intuitive reflection of the degree of winding deformation. Third, current national and industry standards only make simple distinctions based on the transformer voltage level or rated capacity when judging whether radial deformation has occurred in power transformer windings, without considering the differences in winding insulation structure. This leads to a serious lack of sensitivity to radial deformation in windings with high short-circuit impedance.

[0005] Based on the above problems, there is an urgent need to provide a method for judging the deformation of power transformer windings that can accurately determine the deformation and degree of deformation. Summary of the Invention

[0006] The purpose of this application is to provide a method, system, medium, and product for judging radial deformation of power transformer windings, which can accurately judge the deformation and degree of deformation of power transformer windings.

[0007] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for judging radial deformation of power transformer windings, the method comprising: Low-voltage short-circuit reactance tests were conducted between winding pairs of a power transformer to obtain the short-circuit reactance between each phase winding pair; the winding pairs included: high-voltage low-voltage windings and high-voltage medium-voltage windings; Based on the short-circuit reactance between each phase winding pair and the historical short-circuit reactance between each phase winding pair, the rate of change of short-circuit reactance between each phase winding pair is obtained. The capacitance between each phase winding pair of a power transformer is directly measured using the bridge direct connection method; and the rate of change of capacitance between each phase winding pair is determined based on historical capacitance. The winding deformation results are determined based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair. The degree of winding deformation is determined based on the rate of change of short-circuit reactance between each phase winding pair, the short-circuit reactance threshold, and the winding deformation result; the short-circuit reactance threshold is the rate of change between the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance value between winding pairs under the condition of no deformation.

[0008] Optionally, the capacitance between each phase winding pair of the power transformer can be directly measured using the bridge direct connection method, specifically including: Short-circuit the beginning and end of each phase high voltage winding and connect it to the high voltage line output terminal of the bridge; short-circuit the beginning and end of each phase medium voltage winding and connect it to the Cx input terminal of the bridge; short-circuit the beginning and end of each phase low voltage winding and disconnect the core and clamp from grounding; connect the low voltage winding, core, and clamp to the Cx line shield terminal; and test the capacitance between each phase high voltage winding and medium voltage winding. Short-circuit the three phases of each high-voltage winding and connect them to the high-voltage output terminal of the bridge; short-circuit the three phases of each low-voltage winding and connect them to the Cx input terminal of the bridge; short-circuit the three phases of each medium-voltage winding and disconnect the core and clamp from grounding; connect the medium-voltage winding, core, and clamp to the shield terminal of the Cx line; and test the capacitance between each high-voltage winding and the low-voltage winding.

[0009] Optionally, determining the winding deformation result based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair specifically includes: Determine whether the rate of change of short-circuit reactance between each phase winding pair is greater than 0 and the rate of change of capacitance is less than 0. When the judgment result is yes, the winding pair of the corresponding phase has radial deformation.

[0010] Optionally, the degree of winding deformation is determined based on the rate of change of short-circuit reactance between each phase winding pair and the short-circuit reactance threshold, further including: Obtain the winding design parameters of the power transformer; the winding design parameters include: the average radius of the high-voltage winding, the average radius of the medium-voltage winding, the average radius of the low-voltage winding, the radial width of the high-voltage winding, the radial width of the medium-voltage winding, the radial width of the low-voltage winding, the main insulation channel size between the high-voltage winding and the medium-voltage winding, the main insulation channel size between the medium-voltage winding and the low-voltage winding, the main insulation channel size between the low-voltage winding and the core, the average radius of the main insulation channel between the high-voltage winding and the medium-voltage winding, the average radius of the main insulation channel between the medium-voltage winding and the low-voltage winding, and the average reactance height of the winding; The short-circuit reactance value between winding pairs is determined based on the winding design parameters of the power transformer, the inter-winding capacitance, and the short-circuit reactance calculation formula, assuming no deformation occurs. Establish an equivalent simplified model of the most severe radial deformation of the winding; and determine the maximum short-circuit reactance between winding pairs under the condition of the most severe deformation. The short-circuit reactance threshold is determined based on the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance between winding pairs under the condition of no deformation.

[0011] Optionally, the short-circuit reactance value between winding pairs under the condition of no deformation is determined according to the winding design parameters of the power transformer, the inter-winding capacitance, and the short-circuit reactance calculation formula, specifically including: Using formula Determine the short-circuit reactance X between the high-voltage winding and the medium-voltage winding. k ; in, The equivalent leakage magnetic area of ​​the winding pair. , For frequency, For winding, To account for the correction factor between the actual magnetic circuit height and the winding reactance height, , , These are the radial widths of the high-voltage winding and the medium-voltage winding, respectively. This refers to the size of the main insulation channel between the high-voltage and medium-voltage windings. This is the average radius of the main insulation channel between the high-voltage and medium-voltage windings. and These are the average radii of the high-voltage winding and the medium-voltage winding, respectively. This represents the average axial reactance height of the high-voltage winding and the medium-voltage winding.

[0012] Optionally, the short-circuit reactance threshold is determined based on the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance between winding pairs under the condition without deformation, specifically including: Using formula Determine the short-circuit reactance threshold ; Among them, Z k _max is the maximum short-circuit reactance between winding pairs under the condition of most severe deformation, Z k _nom is the short-circuit reactance between winding pairs under the condition that no deformation has occurred.

[0013] Optionally, the degree of winding deformation is determined based on the rate of change of short-circuit reactance between each phase winding pair and the short-circuit reactance threshold, specifically including: The degree of winding deformation is obtained by dividing the rate of change of short-circuit reactance between each phase winding pair by the short-circuit reactance threshold. When the degree of winding deformation is less than or equal to 0.3, the winding is considered to have undergone slight deformation. When the winding deformation is greater than 0.3 and less than or equal to 0.7, the winding is considered to have undergone moderate deformation. When the winding deformation exceeds 0.7, the winding is considered to have undergone severe deformation.

[0014] Secondly, this application provides a system for judging radial deformation of power transformer windings, the system comprising: The short-circuit reactance test module is used to conduct low-voltage short-circuit reactance tests between winding pairs of power transformers to obtain the short-circuit reactance between each phase winding pair; the winding pairs include: high-voltage low-voltage windings and high-voltage medium-voltage windings; The short-circuit reactance change rate determination module is used to obtain the short-circuit reactance change rate between each phase winding pair based on the short-circuit reactance between each phase winding pair and the historical short-circuit reactance between each phase winding pair. The capacitance change rate determination module is used to directly measure the capacitance between each phase winding pair of a power transformer using the bridge positive connection method; and to determine the capacitance change rate between each phase winding pair based on historical capacitance. The winding deformation result determination module is used to determine the winding deformation result based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair. The winding deformation degree determination module is used to determine the winding deformation degree based on the change rate of short-circuit reactance between each phase winding pair, the short-circuit reactance threshold, and the winding deformation result; the short-circuit reactance threshold is the change rate between the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance value between winding pairs under the condition of no deformation.

[0015] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned method for judging radial deformation of power transformer windings.

[0016] Fourthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the aforementioned method for judging radial deformation of power transformer windings.

[0017] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a method, system, medium, and product for judging radial deformation of power transformer windings. By directly measuring the capacitance between each phase winding pair of the power transformer using the bridge positive connection method, the sensitivity of the on-site capacitance test to winding deformation can be improved, thereby improving the accuracy of judging the smallest deformation. By comprehensively analyzing and judging the electrical quantities coupled with the short-circuit reactance change rate and capacitance change rate between each phase winding pair, the accuracy of determining the degree of deformation at the same scale is improved while ensuring that deformation can be judged. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart of a method for judging radial deformation of a power transformer winding in one embodiment of this application; Figure 2 This is a schematic diagram of the insulation structure of one phase of a three-phase, three-winding transformer. Figure 3 This is a schematic diagram showing the layout of the dielectric loss bridge panel used on site and the test using the positive connection method. Figure 4 This is a schematic diagram of the main insulation structure between adjacent windings of different voltage levels in the same phase of a power transformer. Figure 5 A schematic diagram of the inner winding deformation considering the most severe radial deformation state. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] In an exemplary embodiment, when a through-fault current flows through the windings of a power transformer, the two windings on the power supply side and the short-circuit side not only experience the repulsive force between the two windings caused by currents flowing in different directions, but also the attractive force between the conductors carrying the same current within the same winding. The electrodynamic force generated by the short-circuit current results in: the inner winding contracts, the outer winding stretches, and the winding compresses from both ends towards the center. For a properly designed and manufactured power transformer, stretching of the outer winding and compression towards the center are rare; local or overall deformation of the inner winding is currently the main deformation mode of power transformers. To address this main fault mode, such as... Figure 1 As shown, a method for judging radial deformation of power transformer windings is provided, which includes the following steps S101 to S105. Wherein: S101, Conduct a low-voltage short-circuit reactance test between winding pairs of a power transformer to obtain the short-circuit reactance between each phase winding pair; the winding pair includes: high-voltage and low-voltage windings and high-voltage and medium-voltage windings; wherein, the low-voltage short-circuit reactance test is: short-circuit the three phases of the medium-voltage side winding or the low-voltage side winding of the transformer, apply voltage from the high-voltage side winding, and calculate based on the applied voltage and current; The most widely used power transformer in the power grid is the three-phase, three-winding step-down power transformer, such as... Figure 2 As shown, its windings along the iron core are, in sequence, low-voltage winding (LV), medium-voltage winding (MV), and high-voltage winding (HV). When conducting a low-voltage short-circuit reactance test between the high-voltage and medium-voltage winding pairs, the short-circuit reactance X between the high-voltage and medium-voltage winding pairs of phase A is obtained. k Short-circuit reactance X between A_HV_MV_1 and B phase high-voltage medium-voltage winding pairs k B_HV_MV_1, Short-circuit reactance between C-phase high-voltage and medium-voltage winding pairs X k C_HV_MV_1; When conducting a low-voltage short-circuit reactance test between the high-voltage and low-voltage winding pairs, the short-circuit reactance X between the high-voltage and low-voltage winding pairs of phase A is obtained. k Short-circuit reactance X between the high-voltage and low-voltage windings of phases A_HV_LV and B. k Short-circuit reactance between the high-voltage and low-voltage windings of phase B_HV_LV and C-phase X k _VC_HV_LV; S102, based on the short-circuit reactance between each phase winding pair and the historical short-circuit reactance between each phase winding pair, the change rate of short-circuit reactance between each phase winding pair is obtained. Obtain the short-circuit reactance X between the high-voltage and medium-voltage winding pairs of phases A, B, and C. k A_HV_MV_1、X k B_HV_MV_1、X k C_HV_MV_1; and obtain the short-circuit reactance X between the high-voltage and low-voltage winding pairs of phases A, B, and C. k A_HV_LV、X k B_HV_LV、X k C_HV_LV; Furthermore, the difference between the current short-circuit reactance and the historical short-circuit reactance is compared with the historical short-circuit reactance to obtain the rate of change of short-circuit reactance. The rate of change of short-circuit reactance ΔX between the high-voltage and medium-voltage winding pairs of phases A, B, and C are then obtained respectively. k A_HV_MV、ΔX k B_HV_MV、ΔX k The rate of change of short-circuit reactance ΔX between C_HV_MV and the high-voltage and low-voltage winding pairs of phases A, B, and C is also significant. k A_HV_LV、ΔX kB_HV_LV、ΔX k C_HV_LV; S103 uses the bridge direct connection method to directly measure the capacitance between each phase winding pair of the power transformer; and determines the capacitance change rate between each phase winding pair based on historical capacitance. S102 uses the bridge positive connection method to introduce other interference signals into the shielded end of the bridge Cx line, thereby realizing the measurement of the capacitance between winding pairs; such as Figure 3 As shown, Cx corresponds to the inter-pair capacitance C of the high-voltage and medium-voltage windings in Table 1. HV_MV Or the capacitance C between high-voltage and low-voltage windings _HV_LV ; The implementation steps are shown in Table 1. For comparison, Table 2 shows the test methods recommended by current national and industry standards; when testing the capacitance between the high-voltage winding and the medium-voltage winding, the specific steps include: 1. Short-circuit the start and end of each phase high-voltage winding and connect it to the output terminal of the high-voltage line of the bridge; 2. Short-circuit the start and end of the medium voltage winding of each phase and connect it to the input terminal Cx of the bridge; 3. Short-circuit the beginning and end of each phase low-voltage winding, and disconnect the core and clamps from grounding; 4. Connect the low-voltage winding, core, and clamps to the shielding terminal of the Cx line. 5. Test the capacitance between the high-voltage winding and the medium-voltage winding of each phase; When testing the capacitance between the high-voltage winding and the low-voltage winding, the specific steps include: 1. Short-circuit the start and end of each phase high-voltage winding and connect it to the output terminal of the high-voltage line of the bridge; 2. Short-circuit the start and end of each phase low-voltage winding and connect it to the Cx input terminal of the bridge; 3. Short-circuit the start and end of each phase medium voltage winding, and disconnect the core and clamps from grounding; 4. Connect the medium-voltage winding, core, and clamp to the shielding terminal of the Cx line; 5. Test the capacitance between the high-voltage winding and the low-voltage winding of each phase.

[0023] Table 1

[0024] Table 2

[0025] Currently, the capacitance data used to determine the deformation of power transformer windings comes from the dielectric loss and capacitance standard high-voltage electrical test items of the windings and bushings. The test method involves short-circuiting the test winding head-to-tail and short-circuiting the other windings head-to-tail to ground. A voltage is applied to the test winding through a bridge circuit, and the bridge calculates the dielectric loss angle and capacitance based on the output voltage and current. Referring to the insulation structure of power transformers, this test method has the advantage of reflecting the insulation condition between the test winding and the core, yoke, and adjacent windings. However, for determining winding deformation, the effective capacitance is the capacitance between windings. This application proposes using a bridge circuit with the wire directly connected to directly measure the capacitance between winding pairs, thereby improving the sensitivity to capacitance changes.

[0026] S104, the winding deformation result is determined based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair; S105, determine the degree of winding deformation based on the rate of change of short-circuit reactance between each phase winding pair, the short-circuit reactance threshold, and the winding deformation result; the short-circuit reactance threshold is the rate of change between the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance value between winding pairs under the condition of no deformation.

[0027] S105 also included: S1, obtain the winding design parameters of the power transformer; As shown in Table 3, the winding design parameters include: the average radius of the high-voltage winding, the average radius of the medium-voltage winding, the average radius of the low-voltage winding, the radial width of the high-voltage winding, the radial width of the medium-voltage winding, the radial width of the low-voltage winding, the main insulation channel size between the high-voltage winding and the medium-voltage winding, the main insulation channel size between the medium-voltage winding and the low-voltage winding, the main insulation channel size between the low-voltage winding and the core, the average radius of the main insulation channel between the high-voltage winding and the medium-voltage winding, the average radius of the main insulation channel between the medium-voltage winding and the low-voltage winding, and the average reactance height of the winding. Table 3

[0028] S2, determine the short-circuit reactance value between winding pairs without deformation based on the winding design parameters of the power transformer, the inter-winding capacitance and short-circuit reactance calculation formula; Using formula Determine the short-circuit reactance X between the high-voltage winding and the medium-voltage winding. k (Unit: Ohms) in, The equivalent leakage magnetic area of ​​the winding pair. The unit is , For frequency, For the number of turns in a winding, The correction factor used to account for the difference between the actual magnetic circuit height and the winding reactance height is usually called the Rockwell coefficient, which is dimensionless. , , These are the radial widths of the high-voltage winding and the medium-voltage winding, respectively. This refers to the size of the main insulation channel between the high-voltage and medium-voltage windings. This is the average radius of the main insulation channel between the high-voltage and medium-voltage windings. and These are the average radii of the high-voltage winding and the medium-voltage winding, respectively. This represents the average axial reactance height of the high-voltage winding and the medium-voltage winding.

[0029] The formula for calculating the coaxial cylindrical capacitance formed by the windings is: ; Where, The equivalent relative permittivity of the main insulation; Under the action of the electrodynamic force generated by the short-circuit current, the power transformer is subjected to the following conditions: Figure 2 Taking the high-voltage winding and medium-voltage winding as examples, due to the radial width of the winding... and Nothing will change; the only difference is the distance between the main insulation channels between the two windings. The medium-voltage winding undergoes radial deformation due to the compressive force directed towards the core surface, causing its capacitance to increase. As shown in the two formulas above, this inevitably leads to an increase in short-circuit reactance and a decrease in capacitance between the high-voltage and medium-voltage windings. This invention, based on general transformer design parameters and using winding pairs as the basic unit, improves the winding capacitance testing method. On the one hand, it enables the identification of minute deformations; on the other hand, it achieves a normalized judgment of the degree of winding deformation, thus possessing greater practical application value.

[0030] S3, based on Figure 4 The transformer's main insulation structure is shown. Figure 5 The equivalent simplified model of the most severe radial deformation of the winding is shown; and the maximum short-circuit reactance between winding pairs under the condition of the most severe deformation is determined. The process of establishing an equivalent simplified model of the most severe radial deformation of the winding is as follows: The main insulation structure between adjacent windings of different voltage levels in the same phase of a power transformer is as follows: Figure 4 As shown, Figure 4The insulating paper tube, the evenly distributed support strips adhered to the circumference of the insulating paper tube, and the insulating oil together constitute the main insulation between windings of different voltage levels. The thickness of the support strips along the radial direction is the distance of the oil gap between the main insulation components. For winding pairs of a specific voltage level, products from different manufacturers have similar main insulation structures, and the percentage of the oil gap occupying the total insulation distance does not differ significantly. In practice, the most severe radial deformation mode is as follows: Figure 5 As shown, the windings between the uniformly arranged support bars along the circumference undergo bending deformation due to inward radial forces. Since the insulating paper tube and support bars can be considered incompressible, the inward deformation of the windings between adjacent support bars is limited, with the maximum being the difference between the distance of the main insulation channel and the thickness of the insulating paper tube. At the support bar location, the dimension is considered constant. Because the support bars are uniformly arranged, the equivalent radius reduction after deformation of the inner winding can be considered to be... It is half the difference between the distance of the main insulation channel and the thickness of the insulation paper tube.

[0031] S4. Determine the short-circuit reactance threshold based on the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance between winding pairs under the condition without deformation.

[0032] Using formula Determine the short-circuit reactance threshold ; Among them, Z k _max is the maximum short-circuit reactance between winding pairs under the condition of most severe deformation, Z k _nom is the short-circuit reactance between winding pairs under the condition that no deformation has occurred.

[0033] S105 specifically includes: S51, divide the rate of change of short-circuit reactance between each phase winding pair by the short-circuit reactance threshold to obtain the degree of winding deformation. S52, when the winding deformation is less than or equal to 0.3, the winding undergoes slight deformation; S53, when the winding deformation is greater than 0.3 and less than or equal to 0.7, the winding undergoes moderate deformation; S54: When the winding deformation exceeds 0.7, severe winding deformation occurs. It is recommended to determine the transformer maintenance strategy based on the actual site conditions.

[0034] Based on the same inventive concept, this application also provides a power transformer winding radial deformation judgment system for implementing the above-mentioned power transformer winding radial deformation judgment method. The solution provided by this system is similar to the implementation scheme described in the above method. Therefore, the specific limitations of one or more power transformer winding radial deformation judgment system embodiments provided below can be found in the limitations of the power transformer winding radial deformation judgment method described above, and will not be repeated here.

[0035] In one exemplary embodiment, a power transformer winding radial deformation determination system is provided, comprising: The short-circuit reactance test module is used to conduct low-voltage short-circuit reactance tests between winding pairs of power transformers to obtain the short-circuit reactance between each phase winding pair; the winding pairs include: high-voltage low-voltage windings and high-voltage medium-voltage windings; The short-circuit reactance change rate determination module is used to obtain the short-circuit reactance change rate between each phase winding pair based on the short-circuit reactance between each phase winding pair and the historical short-circuit reactance between each phase winding pair. The capacitance change rate determination module is used to directly measure the capacitance between each phase winding pair of a power transformer using the bridge positive connection method; and to determine the capacitance change rate between each phase winding pair based on historical capacitance. The winding deformation result determination module is used to determine the winding deformation result based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair. The winding deformation degree determination module is used to determine the winding deformation degree based on the change rate of short-circuit reactance between each phase winding pair, the short-circuit reactance threshold, and the winding deformation result; the short-circuit reactance threshold is the change rate between the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance value between winding pairs under the condition of no deformation.

[0036] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0037] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0038] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0039] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0040] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0041] In this application, all actions to acquire signals, information, or data are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with the authorization granted by the owner of the relevant device.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for judging radial deformation of power transformer windings, characterized in that, The method for judging radial deformation of power transformer windings includes: Low-voltage short-circuit reactance tests were conducted between winding pairs of a power transformer to obtain the short-circuit reactance between each phase winding pair; the winding pairs included: high-voltage low-voltage windings and high-voltage medium-voltage windings; Based on the short-circuit reactance between each phase winding pair and the historical short-circuit reactance between each phase winding pair, the rate of change of short-circuit reactance between each phase winding pair is obtained. The capacitance between each phase winding pair of a power transformer is directly measured using the bridge direct connection method; and the rate of change of capacitance between each phase winding pair is determined based on historical capacitance. The winding deformation results are determined based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair. The degree of winding deformation is determined based on the rate of change of short-circuit reactance between each phase winding pair, the short-circuit reactance threshold, and the winding deformation result; the short-circuit reactance threshold is the rate of change between the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance value between winding pairs under the condition of no deformation.

2. The method for judging radial deformation of power transformer windings according to claim 1, characterized in that, The capacitance between each phase winding pair of a power transformer is directly measured using the bridge direct connection method, specifically including: Short-circuit the beginning and end of each phase high voltage winding and connect it to the high voltage line output terminal of the bridge; short-circuit the beginning and end of each phase medium voltage winding and connect it to the Cx input terminal of the bridge; short-circuit the beginning and end of each phase low voltage winding and disconnect the core and clamp from grounding; connect the low voltage winding, core, and clamp to the Cx line shield terminal; and test the capacitance between each phase high voltage winding and medium voltage winding. Short-circuit the three phases of each high-voltage winding and connect them to the high-voltage output terminal of the bridge; short-circuit the three phases of each low-voltage winding and connect them to the Cx input terminal of the bridge; short-circuit the three phases of each medium-voltage winding and disconnect the core and clamp from grounding; connect the medium-voltage winding, core, and clamp to the shield terminal of the Cx line; and test the capacitance between each high-voltage winding and the low-voltage winding.

3. The method for judging radial deformation of power transformer windings according to claim 1, characterized in that, The determination of winding deformation results based on the rate of change of short-circuit reactance and the rate of change of capacitance between each phase winding pair specifically includes: Determine whether the rate of change of short-circuit reactance between each phase winding pair is greater than 0 and the rate of change of capacitance is less than 0. When the judgment result is yes, the winding pair of the corresponding phase has radial deformation.

4. The method for judging radial deformation of power transformer windings according to claim 1, characterized in that, The degree of winding deformation is determined based on the rate of change of short-circuit reactance between each phase winding pair and the short-circuit reactance threshold. This process also includes: Obtain the winding design parameters of the power transformer; the winding design parameters include: the average radius of the high-voltage winding, the average radius of the medium-voltage winding, the average radius of the low-voltage winding, the radial width of the high-voltage winding, the radial width of the medium-voltage winding, the radial width of the low-voltage winding, the main insulation channel size between the high-voltage winding and the medium-voltage winding, the main insulation channel size between the medium-voltage winding and the low-voltage winding, the main insulation channel size between the low-voltage winding and the core, the average radius of the main insulation channel between the high-voltage winding and the medium-voltage winding, the average radius of the main insulation channel between the medium-voltage winding and the low-voltage winding, and the average reactance height of the winding; The short-circuit reactance value between winding pairs is determined based on the winding design parameters of the power transformer, the inter-winding capacitance, and the short-circuit reactance calculation formula, assuming no deformation occurs. Establish an equivalent simplified model of the most severe radial deformation of the winding; and determine the maximum short-circuit reactance between winding pairs under the condition of the most severe deformation. The short-circuit reactance threshold is determined based on the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance between winding pairs under the condition of no deformation.

5. The method for judging radial deformation of power transformer windings according to claim 4, characterized in that, The short-circuit reactance between winding pairs is determined based on the winding design parameters of the power transformer, the inter-winding capacitance, and the short-circuit reactance calculation formula, under the condition that no deformation has occurred. Specifically, this includes: Using formula Determine the short-circuit reactance X between the high-voltage winding and the medium-voltage winding. k ; in, The equivalent leakage magnetic area of ​​the winding pair. , For frequency, For winding, To account for the correction factor between the actual magnetic circuit height and the winding reactance height, , , These are the radial widths of the high-voltage winding and the medium-voltage winding, respectively. This refers to the size of the main insulation channel between the high-voltage and medium-voltage windings. This is the average radius of the main insulation channel between the high-voltage and medium-voltage windings. and These are the average radii of the high-voltage winding and the medium-voltage winding, respectively. This represents the average axial reactance height of the high-voltage winding and the medium-voltage winding.

6. The method for judging radial deformation of power transformer windings according to claim 4, characterized in that, The short-circuit reactance threshold is determined based on the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance between winding pairs under the condition without deformation. Specifically, this includes: Using formula Determine the short-circuit reactance threshold ; Among them, Z k _max is the maximum short-circuit reactance between winding pairs under the condition of most severe deformation, Z k _nom is the short-circuit reactance between winding pairs under the condition that no deformation has occurred.

7. The method for judging radial deformation of power transformer windings according to claim 1, characterized in that, The degree of winding deformation is determined based on the rate of change of short-circuit reactance between each phase winding pair and the short-circuit reactance threshold, specifically including: The degree of winding deformation is obtained by dividing the rate of change of short-circuit reactance between each phase winding pair by the short-circuit reactance threshold. When the degree of winding deformation is less than or equal to 0.3, the winding is considered to have undergone slight deformation. When the winding deformation is greater than 0.3 and less than or equal to 0.7, the winding is considered to have undergone moderate deformation. When the winding deformation exceeds 0.7, the winding is considered to have undergone severe deformation.

8. A system for judging radial deformation of power transformer windings, characterized in that, The power transformer winding radial deformation judgment system includes: The short-circuit reactance test module is used to conduct low-voltage short-circuit reactance tests between winding pairs of power transformers to obtain the short-circuit reactance between each phase winding pair; the winding pairs include: high-voltage low-voltage windings and high-voltage medium-voltage windings; The short-circuit reactance change rate determination module is used to obtain the short-circuit reactance change rate between each phase winding pair based on the short-circuit reactance between each phase winding pair and the historical short-circuit reactance between each phase winding pair. The capacitance change rate determination module is used to directly measure the capacitance between each phase winding pair of a power transformer using the bridge positive connection method; and to determine the capacitance change rate between each phase winding pair based on historical capacitance. The winding deformation result determination module is used to determine the winding deformation result based on the rate of change of short-circuit reactance between each phase winding pair and the rate of change of capacitance between each phase winding pair. The winding deformation degree determination module is used to determine the winding deformation degree based on the change rate of short-circuit reactance between each phase winding pair, the short-circuit reactance threshold, and the winding deformation result; the short-circuit reactance threshold is the change rate between the maximum short-circuit reactance between winding pairs under the most severe deformation condition and the short-circuit reactance value between winding pairs under the condition of no deformation.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for judging radial deformation of power transformer windings as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the method for judging radial deformation of power transformer windings as described in any one of claims 1-7.

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