A transformer winding inter-turn fault simulation device and fault location method

Abstract

The present invention discloses a transformer winding inter-turn fault simulation device and a fault locating method. By establishing an accurate ladder network model and combining it with the reference frequency response curve analysis of high and low frequency bands, the fault position is accurately located. Not only can fault diagnosis be completed without disassembling the transformer, but detection can also be performed under the running state. At the same time, the method adopts scientific mathematical modeling and parameter derivation, so that the fault location has a reliable theoretical basis and is suitable for fault detection of various transformer windings. It has the characteristics of simple operation, accurate calculation, strong adaptability, etc., and provides a high-efficiency and reliable technical solution for preventive maintenance and fault diagnosis of transformers.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer fault detection, and in particular to a transformer winding inter-turn fault simulation device and a fault locating method. Background Art

[0002] Transformers are critical components of power systems. Failures can significantly increase operating costs for utilities and severely impact the stability of power supply. Research shows that winding failures are the primary cause of transformer failures, accounting for approximately 30% of total failure rates. These failures typically occur due to faults between turns or between turns within the winding. When a transformer winding fails, high currents flow through the damaged winding, causing localized overheating in the faulted area and further damaging the winding's insulation. Furthermore, the high currents can impact surrounding windings, causing axial or radial deformation, ultimately leading to complete transformer failure. Therefore, it is crucial to promptly and accurately locate interturn faults in transformer windings and perform repairs to prevent further damage.

[0003] Currently, for transformer fault location, infrared thermal imaging technology can identify the fault location by detecting local overheating, but this method has limited ability to detect internal faults; ultrasonic detection and vibration analysis can identify abnormalities within the winding by analyzing ultrasonic signals and vibration patterns, but these methods are easily interfered with and rely on experience; oil chromatography analysis determines whether there are signs of faults by analyzing the dissolved gas components in the transformer oil. Although this method can provide some useful information, it cannot directly locate the fault location. In response to the above problems, in order to improve the accuracy and efficiency of transformer winding interturn fault location, this patent introduces a transformer winding interturn fault simulation device and fault location method, which is of great significance for ensuring the operational reliability of the power system. Summary of the Invention

[0004] The present invention provides a transformer winding inter-turn fault simulation device and a fault locating method, which improve the accuracy and controllability of fault simulation.

[0005] The present invention discloses a method for locating a transformer winding inter-turn fault, the method comprising:

[0006] Establish a ladder network model consisting of shunt capacitors and series capacitors for the transformer winding;

[0007] Obtaining reference frequency response curves of a selected turn of the transformer in a low-frequency band and a high-frequency band before a pre-fault condition; calculating initial values ​​of the segmented shunt capacitors corresponding to each segment of the transformer winding and the segmented series capacitors corresponding to each segment of the transformer winding in the ladder network model based on the reference frequency response curves of the low-frequency band and the high-frequency band;

[0008] Calculating the inter-turn fault factor of each transformer winding in a pre-fault state based on the initial values ​​of the segmented parallel capacitor and the segmented series capacitor;

[0009] After a fault occurs in the transformer winding, a fault reference frequency response curve of a high frequency band of a selected turn winding of the transformer is obtained, and an inter-turn fault factor under a fault state is calculated based on the fault reference frequency response curve;

[0010] Calculating the deviation between the inter-turn fault factor of each section of the transformer winding in the pre-fault state and the inter-turn fault factor in the fault state;

[0011] The inter-turn fault factor is: ;

[0012] Where ITFF is the inter-turn fault factor; C 1-0 、C 2-0 is the equivalent capacitance between terminals before fault; 、 is the equivalent capacitance between terminals after the fault;

[0013] When the deviation value is less than zero for the first time, it is determined that the i-th transformer winding or the i-1-th transformer winding has a fault, where i≥1 and i∈N.

[0014] Furthermore, obtaining reference frequency response curves of the selected turn winding of the transformer in the low-frequency band and the high-frequency band before the pre-fault; calculating the initial values ​​of the segmented parallel capacitance corresponding to each segment of the transformer winding and the segmented series capacitance corresponding to each segment of the transformer winding in the ladder network model based on the reference frequency response curves of the low-frequency band and the high-frequency band includes:

[0015] When a reference frequency is selected at a low frequency, at the reference frequency, the inter-terminal equivalent capacitance is calculated based on the inter-terminal impedance of the transformer winding, and then the initial value of the segmented parallel capacitance is calculated based on the inter-terminal equivalent capacitance of the transformer winding before the pre-fault. The initial value is:

[0016] ;

[0017] Among them, C g is the initial value of the segmented parallel capacitance, C L1-0 is the equivalent capacitance between terminals of the transformer winding before the pre-fault condition; N is the order of the ladder network model;

[0018] When a reference frequency is selected in a high frequency band, based on a star-to-delta equivalent transformation method, a ratio of the pre-fault inter-terminal equivalent capacitance to the segmented parallel capacitance is calculated at the reference frequency, and an initial value of the segmented series capacitance is calculated based on the ratio.

[0019] Furthermore, the inter-turn fault factor in the pre-fault state is:

[0020] ;

[0021] Among them, ITFF pre (i) is the inter-turn fault factor of each transformer winding in the transformer ladder network model under the pre-fault state; K i is the constant of the i-th transformer winding in the pre-fault state; a1(i), a2(i), b1(i), b2(i) are the coefficients of the i-th transformer winding in the pre-fault state; C si is the segmented series capacitance value of the i-th transformer winding;

[0022] ;

[0023] ;

[0024] ;

[0025] ;

[0026] in, , ; C 2i 、C 22i are the total series equivalent capacitance and parallel equivalent capacitance of segments i+1 to N, respectively; C 1i 、C 11i are the total series equivalent capacitance and parallel equivalent capacitance of segments 1 to i-1, respectively.

[0027] Furthermore, the inter-turn fault factor under the fault state is:

[0028] ;

[0029] Among them, ITFF post is the inter-turn fault factor under the fault state; C 1-0 、C 2-0 is the equivalent capacitance between terminals measured before the pre-fault condition when the reference frequency is selected in the high frequency band; 、 It is the equivalent capacitance between terminals measured when the reference frequency is selected in the high frequency band after a fault occurs.

[0030] Furthermore, when the deviation value between the inter-turn fault factor of the i-th section transformer winding in the pre-fault state and the inter-turn fault factor in the fault state is less than 0, if the inter-turn fault factor in the fault state is less than 0, the fault occurs in the i-th section transformer winding; if the inter-turn fault factor in the fault state is greater than 0, the fault occurs in the i-1-th section transformer winding.

[0031] On the other hand, the present invention also discloses a transformer winding inter-turn fault simulation device, comprising:

[0032] Vertical lifting mechanism;

[0033] a supporting structure slidably connected to the vertical lifting mechanism in a vertical direction;

[0034] A horizontal adjustment mechanism is slidably connected to the support structure in the horizontal direction through a screw-nut pair, and a short-circuit actuator is provided at one end of the horizontal adjustment mechanism away from the support structure;

[0035] The short-circuit actuator is used to clamp the selected turns of the transformer and establish a short-circuit loop between the selected turns of the transformer;

[0036] And, a signal acquisition system is used to perform fault detection on selected turns of the transformer.

[0037] Furthermore, the vertical lifting mechanism includes a vertical lift column, a slide chute, a slider, a transmission gear, a rack guide, a first stepper motor and a transmission threaded rod;

[0038] The slide groove is provided on the outer surface of the vertical lift column, and the slider is embedded in the slide groove;

[0039] The rack guide rail is provided on the outer surface of the vertical lift column and meshes with the transmission gear;

[0040] One end of the transmission threaded rod is connected to the transmission gear, and the other end is connected to the output shaft of the first stepper motor.

[0041] Furthermore, the support structure includes a support wall, a support platform and a fixing plate;

[0042] The support wall is slidably connected to the slide groove via the slider;

[0043] The support platform is fixedly connected to the top of the support wall through the fixing plate, and the support platform is used to carry the horizontal adjustment mechanism.

[0044] Furthermore, the horizontal adjustment mechanism includes a second stepping motor, a telescopic cylinder, a gear set, a trapezoidal lead screw, a trapezoidal nut and a connector;

[0045] The second stepper motor is fixed on the supporting platform;

[0046] The driving wheel in the gear set is connected to the output shaft of the second stepping motor, and the driven wheel in the gear set is key-connected to the trapezoidal lead screw;

[0047] The trapezoidal nut is sleeved on the trapezoidal lead screw and forms a threaded fit with the trapezoidal lead screw;

[0048] One end of the telescopic cylinder is connected to the trapezoidal nut, and the other end is connected to one end of the connector; the other end of the connector is connected to the short-circuit actuator.

[0049] Furthermore, the short-circuit actuator comprises: a metal clamping jaw, a hydraulic device and a loop wire;

[0050] One end of the metal clamp is connected to the connector via the hydraulic device;

[0051] One end of the loop wire is electrically connected to the metal clamp, and the other end is electrically connected to the selected turn winding of the transformer.

[0052] Compared with the prior art, the present invention has at least the following technical effects:

[0053] The present invention achieves accurate positioning of the fault position by establishing an accurate ladder network model and combining it with the reference frequency response curve analysis of high and low frequency bands. Not only can fault diagnosis be completed without disassembling the transformer, but detection can also be performed during operation. At the same time, the method adopts scientific mathematical modeling and parameter derivation, which provides a reliable theoretical basis for fault positioning and is suitable for fault detection of various types of transformer windings. It has the characteristics of simple operation, accurate calculation, and strong adaptability, and provides an efficient and reliable technical solution for preventive maintenance and fault diagnosis of transformers.

[0054] Furthermore, in the design of the transformer winding inter-turn fault simulation device, the present invention realizes the precise positioning of any position of the transformer winding through the cooperation of the vertical lifting mechanism and the horizontal adjustment mechanism. Among them, the sliding connection between the vertical lifting mechanism and the support structure ensures the continuous adjustability of the vertical position, and the sliding connection between the horizontal adjustment mechanism and the support structure through the screw nut pair ensures the precise control of the horizontal position. The short-circuit actuator is set at the end of the horizontal adjustment mechanism, and can accurately clamp any selected turn winding and establish a short-circuit loop with the cooperation of the positioning system. Combined with the real-time monitoring of the signal acquisition system, it realizes the reliable simulation and reliable detection of transformer winding inter-turn faults. This design not only improves the accuracy and controllability of fault simulation, but also reduces the difficulty of manual operation, and provides a reliable experimental platform for the study of transformer winding inter-turn faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a flow chart of a method for locating a transformer winding inter-turn fault in a first embodiment of the present invention;

[0056] Figure 2 is a flow chart of another transformer winding inter-turn fault location method in embodiment 1 of the present invention;

[0057] Figure 3 In the first embodiment of the present invention, L Improved transformer capacitor ladder network model under the scope;

[0058] Figure 4 In the first embodiment of the present invention, H Improved transformer capacitor ladder network model under the scope;

[0059] Figure 5 is the equivalent ladder network model of the i-th segment in the pre-fault state in the first embodiment of the present invention;

[0060] Figure 6 1 is a schematic structural diagram of a transformer winding inter-turn fault simulation device in a second embodiment of the present invention;

[0061] Figure 7 This is a wiring diagram of the signal acquisition system in the second embodiment of the present invention.

[0062] In the figure, there are a basic working platform 1, a transformer winding core 2, a winding coil 3, a vertical elevator column 4, a slide 5, a support wall 6, a support platform 7, a rack guide rail 8, a transmission gear 9, a transmission threaded rod 10, a fixing plate 11, a first stepper motor 12, a second stepper motor 13, a gear set 14, a trapezoidal lead screw 15, a trapezoidal nut 16, a telescopic cylinder 17, a connecting head 18, a metal clamp 19, a hydraulic device 20, a loop wire 21, an excitation generating device 22, a signal acquisition device 23, a roller 24, a second connecting wire 25, and a first connecting wire 26. DETAILED DESCRIPTION

[0063] The following describes a transformer winding interturn fault simulation device and fault location method according to the present invention with reference to schematic diagrams. Preferred embodiments of the present invention are shown. It should be understood that those skilled in the art may modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as generally known to those skilled in the art and is not intended to limit the present invention.

[0064] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are provided solely for the purpose of assisting in the description of the embodiments of the present invention.

[0065] Example 1

[0066] Please refer to Figure 1-Figure 5 This embodiment discloses a method for locating a transformer winding turn-to-turn fault. Specifically, the method includes the following steps:

[0067] S1. Establish a ladder network model for the transformer winding;

[0068] S2. Obtaining the reference frequency response curves of the selected turn winding of the transformer in the low-frequency band and the high-frequency band before the pre-fault; calculating the initial values ​​of the segmented parallel capacitor and the segmented series capacitor in the ladder network model based on the reference frequency response curves of the low-frequency band and the high-frequency band;

[0069] S3. Calculate the inter-turn fault factor under the pre-fault state of the i-th segment based on the initial value of the segmented parallel capacitor and the segmented series capacitor;

[0070] S4. After a fault occurs in the transformer winding, obtaining a fault reference frequency response curve of a high-frequency band of a selected turn winding of the transformer, and calculating an inter-turn fault factor under a fault state based on the fault reference frequency response curve;

[0071] S5. Calculate the deviation between the inter-turn fault factor of each section of the transformer winding in the pre-fault state and the inter-turn fault factor in the fault state;

[0072] S6. When the deviation value is less than zero for the first time, determine that the i-th transformer winding or the i-1-th transformer winding is faulty; where i≥1, i∈N.

[0073] Specifically, the inter-turn fault factor is: ;

[0074] Where ITFF is the inter-turn fault factor; C 1-0 、C 2-0 is the equivalent capacitance between terminals before fault; 、 is the equivalent capacitance between terminals after the fault.

[0075] In this embodiment, by establishing an accurate ladder network model and combining it with the reference frequency response curve analysis of high and low frequency bands, the fault position is accurately located. Not only can fault diagnosis be completed without disassembling the transformer, but detection can also be performed under the operating state; at the same time, this method adopts scientific mathematical modeling and parameter derivation, so that the fault location has a reliable theoretical basis and is suitable for fault detection of various types of transformer windings. It has the characteristics of simple operation, accurate calculation, and strong adaptability, and provides an efficient and reliable technical solution for preventive maintenance and fault diagnosis of transformers.

[0076] In step S1, a ladder network model is established for the transformer winding. This means that the transformer winding is equivalent to a multi-segment network structure composed of series capacitors and shunt capacitors. Each segment contains the same electrical parameters: the series capacitors are used to represent the capacitive coupling relationship between adjacent turns, and the shunt capacitors are used to represent the capacitive coupling relationship between the turns and the ground. This model can accurately reflect the high-frequency characteristics of the transformer winding and the capacitance distribution between each segment, providing a basis for subsequent fault detection.

[0077] In step S2, obtaining reference frequency response curves of the selected turn winding of the transformer in the low frequency band and the high frequency band before the pre-fault state; calculating the initial values ​​of the segmented parallel capacitor and the segmented series capacitor in the ladder network model based on the reference frequency response curves of the low frequency band and the high frequency band includes:

[0078] Please refer to Figure 3 In F L Improved transformer capacitor ladder network model under the range, in the low frequency band F L Select reference frequency F under range Lr , at the reference frequency F Lr The equivalent capacitance C is calculated from the impedance between terminals. L1-0 , the initial value of the segmented parallel capacitor is:

[0079] ; (1)

[0080] Among them, C g is the initial value of the segmented parallel capacitance, C L1-0 is the equivalent capacitance between the terminals of the transformer winding before the fault; N is the order of the ladder network model.

[0081] For further information, please refer to Figure 4 In F H The improved transformer capacitor ladder network model under the range of high frequency band F H Select the reference frequency F Hr When the pre-fault period is reached, the ratio of the equivalent capacitance between the terminals before the pre-fault condition to the segmented parallel capacitance is calculated based on the star-to-delta equivalent transformation method at the reference frequency, and the initial value of the segmented series capacitance is calculated based on the ratio.

[0082] In step S3, the inter-turn fault factor in the pre-fault state is:

[0083] ;

[0084] Among them, ITFF pre (i) is the inter-turn fault factor of each transformer winding in the transformer ladder network model under the pre-fault state; K iis the constant of the i-th transformer winding in the pre-fault state; a1(i), a2(i), b1(i), b2(i) are the coefficients of the i-th transformer winding in the pre-fault state; C si is the segmented series capacitance value of the i-th transformer winding;

[0085] ;

[0086] ;

[0087] ;

[0088] ;

[0089] in, , ; C 2i 、C 22i are the total series equivalent capacitance and parallel equivalent capacitance of segments i+1 to N, respectively; C 1i 、C 11i are the total series equivalent capacitance and parallel equivalent capacitance of segments 1 to i-1, respectively.

[0090] In steps S5 and S6, the ITFF of the faulty transformer is post The individual calculated values ​​of ITFF pre By comparing the value of (i), the accurate fault location of the transformer can be obtained.

[0091] Specifically, the calculation starts from i=1. pre (i)With ITFF post The minimum deviation value d, , when d is less than 0; combined with ITFF post Locate the fault location. If ITFF post If ITFF is less than 0, the fault is on the i-th transformer winding. post If it is greater than 0, the fault is on the i-1th transformer winding.

[0092] Example 2

[0093] Please refer to Figure 6 Based on the same inventive concept, this embodiment discloses a transformer winding inter-turn fault simulation device, which simulates the fault of the transformer winding that is located using the transformer winding inter-turn fault location method disclosed in the first embodiment.

[0094] Specifically, the transformer winding inter-turn fault simulation device includes:

[0095] A vertical lifting mechanism; a support structure, slidably connected to the vertical lifting mechanism; a horizontal adjustment mechanism, slidably connected to the support structure via a screw-nut pair, a short-circuit actuator being provided at one end of the horizontal adjustment mechanism away from the support structure; the short-circuit actuator being used to clamp selected turns of the transformer and establish a short-circuit loop between the selected turns of the transformer; and a signal acquisition system, being used to perform fault detection on the selected turns of the transformer.

[0096] In this embodiment, precise positioning of any position of the transformer winding is achieved through the cooperation of the vertical lifting mechanism and the horizontal adjustment mechanism. Among them, the sliding connection between the vertical lifting mechanism and the support structure ensures the continuous adjustability of the vertical position, and the sliding connection between the horizontal adjustment mechanism and the support structure through the screw nut pair ensures the precise control of the horizontal position. The short-circuit actuator is set at the end of the horizontal adjustment mechanism, and can accurately clamp any selected turn winding and establish a short-circuit loop with the cooperation of the positioning system. Combined with the real-time monitoring of the signal acquisition system, reliable simulation and reliable detection of transformer winding inter-turn faults are achieved. This design not only improves the accuracy and controllability of fault simulation, but also reduces the difficulty of manual operation, providing a reliable experimental platform for the study of transformer winding inter-turn faults.

[0097] In a specific embodiment, the vertical lifting mechanism includes: a slide 5, a rack guide 8, a transmission gear 9, a transmission threaded rod 10 and a first stepper motor 12.

[0098] Specifically, the slide groove 5 is arranged on the outer surface of the vertical lift column 4, and a slider is embedded in the slide groove 5; the rack guide rail 8 is arranged on the outer surface of the vertical lift, for engaging with the transmission gear 9; one end of the transmission threaded rod 10 is connected to the transmission gear 9, and the other end is connected to the output shaft of the first stepper motor 12.

[0099] In another specific embodiment, the support structure includes a support wall 6 , a support platform 7 and a fixing plate 11 .

[0100] Specifically, the support wall 6 is slidably connected to the slide groove 5 through the slider; the support platform 7 is fixedly connected to the top of the support wall 6 through a fixing plate 11, and the support platform 7 is used to carry the horizontal adjustment mechanism.

[0101] In another specific embodiment, the horizontal adjustment mechanism includes: a second stepping motor 13 , a gear set 14 , a trapezoidal nut 16 , a telescopic cylinder 17 , a trapezoidal lead screw 15 and a connector 18 .

[0102] Specifically, the second stepper motor 13 is fixed on the support platform 7; the driving wheel in the gear set 14 is connected to the output shaft of the second stepper motor 13 for adjusting the transmission ratio and the rotation speed; the driving wheel in the gear set 14 is connected to the output shaft of the second stepper motor 13, and the driven wheel in the gear set 14 is key-connected to the trapezoidal lead screw 15. The trapezoidal lead screw 15 is used to convert rotational motion into linear motion. The trapezoidal nut 16 is sleeved on the trapezoidal lead screw 15 and forms a threaded fit with the trapezoidal lead screw 15. The trapezoidal nut 16 generates horizontal linear motion as the trapezoidal lead screw 15 rotates; one end of the telescopic cylinder 17 is connected to the trapezoidal nut 16, and the other end is connected to the connector 18; the connector 18 is connected to the short-circuit actuator.

[0103] In a specific embodiment, the rear end of the telescopic cylinder 17 is fixedly connected to the trapezoidal nut 16 by bolts, and the front end is bolted to the connector 18 by a flange; the connector 18 and the short-circuit actuator are fixedly connected by a clamp.

[0104] In another specific embodiment, the short-circuit actuator includes: a metal clamping jaw 19 , a hydraulic device 20 and a loop wire 21 .

[0105] One end of the metal clamp 19 is connected to the connector 18 via the hydraulic device 20. Specifically, the hydraulic device 20 is connected to the hydraulic cylinder of the metal clamp 19 to control the opening and closing of the metal clamp 19. Furthermore, a loop conductor 21 is electrically connected to the metal clamp 19 at one end and to the selected turns of the transformer at the other end, establishing a short-circuit loop between the selected turns of the transformer.

[0106] In a specific embodiment, the metal clamp 19 can grab two adjacent turns of transformer windings, or can grab three turns of transformer windings at the same time, thereby realizing fault simulation of two or three turns of transformer windings.

[0107] Please refer to Figure 7 Furthermore, in this embodiment, the signal acquisition system includes an excitation generating device 22 and a signal acquisition device 23.

[0108] In this embodiment, the excitation generating device 22 is connected to the lower end of the transformer winding through a first connecting wire 26 to generate a sinusoidal excitation signal; the signal collecting device 23 is connected to the upper end of the transformer winding through a second connecting wire 25 to collect the response signal.

[0109] In a specific embodiment, the frequency of the sinusoidal excitation signal emitted by the excitation generating device 22 is in the range of 20Hz-2MHz; the signal acquisition device 23 is used to collect the reference frequency response curve in the transformer winding, providing a 10mV-2V sinusoidal scanning signal with a frequency variation of 20Hz-2MHz.

[0110] In this embodiment, the signal detection process is achieved through the collaborative work of the excitation generating device 22 and the signal acquisition device 23: first, the excitation generating device 22 generates a sinusoidal excitation signal with a frequency within a certain range, and inputs it to the lower end of the transformer winding through the first connecting wire 26; when the signal is transmitted in the winding, if it passes through the short-circuit fault point, its transmission characteristics will change; the signal acquisition device 23 collects the response signal reaching the upper end of the transformer winding through the second connecting wire 25, and records the response characteristics at different frequencies to form a reference frequency response curve; by analyzing the difference between the reference frequency response curves under normal and fault conditions, the short-circuit fault can be detected and located.

[0111] Preferably, in this embodiment, the transformer winding (the basic structure of the transformer winding is formed by the combination of the transformer winding core 2 and the winding coil 3), the vertical lifting mechanism and the signal acquisition system are all arranged on the basic working platform 1.

[0112] Further preferably, the bottom surface of the basic working platform 1 is provided with rollers 24. The design of the rollers 24 gives the device good mobility, facilitates rapid transfer and deployment between different testing sites, and significantly improves the practicality and work efficiency of the equipment.

[0113] The operation mode of the above transformer winding inter-turn fault simulation device and signal acquisition system is as follows:

[0114] 1) Fix the transformer winding and the elevator column on the basic working platform 1;

[0115] 2) Operate the first stepper motor 12 to drive the transmission threaded rod 10 to rotate, further driving the transmission gear 9 to rotate on the rack guide rail 8, so that the support structure moves vertically to the simulated inter-turn short circuit fault position;

[0116] 3) Operate the second stepper motor 13 to rotate the gear set 14, which in turn rotates the horizontally placed trapezoidal lead screw 15. The lead screw 15 rotates, which in turn moves the trapezoidal nut 16, thereby pushing the telescopic cylinder 17. This causes the connector 18 to move horizontally, approaching the metal clamping jaws 19 to contact the transformer winding.

[0117] 4) Operate the hydraulic device 20 connected to the metal clamp 19 and cooperate with the horizontal adjustment mechanism to control the clamp to grab two adjacent turns of the transformer coil, further forming an electrical loop between the contact point, the metal clamp 19, and the return wire 21, causing a short circuit fault between the transformer winding turns;

[0118] 5) Repeat the above steps to simulate faults in different locations.

[0119] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for locating a transformer winding turn-to-turn fault, characterized in that: The method comprises: Establish a ladder network model consisting of shunt capacitors and series capacitors for the transformer winding; Obtaining reference frequency response curves of a selected turn of the transformer in a low-frequency band and a high-frequency band before a pre-fault condition; calculating initial values ​​of the segmented shunt capacitors corresponding to each segment of the transformer winding and the segmented series capacitors corresponding to each segment of the transformer winding in the ladder network model based on the reference frequency response curves of the low-frequency band and the high-frequency band; Calculating the inter-turn fault factor of each transformer winding in a pre-fault state based on the initial values ​​of the segmented parallel capacitor and the segmented series capacitor; After a fault occurs in the transformer winding, a fault reference frequency response curve of a high frequency band of a selected turn winding of the transformer is obtained, and an inter-turn fault factor under a fault state is calculated based on the fault reference frequency response curve; Calculating the deviation between the inter-turn fault factor of each section of the transformer winding in the pre-fault state and the inter-turn fault factor in the fault state; The inter-turn fault factor is: ; Where ITFF is the inter-turn fault factor; C 1-0 、C 2-0 is the equivalent capacitance between terminals before fault; 、 is the equivalent capacitance between terminals after the fault; When the deviation value is less than zero for the first time, it is determined that the i-th transformer winding or the i-1-th transformer winding has a fault, where i≥1 and i∈N.

2. The transformer winding inter-turn fault location method according to claim 1, characterized in that: Obtaining reference frequency response curves of the selected turn winding of the transformer in a low-frequency band and a high-frequency band before a pre-fault condition; and calculating initial values ​​of the segmented parallel capacitance corresponding to each segment of the transformer winding and the segmented series capacitance corresponding to each segment of the transformer winding in the ladder network model based on the reference frequency response curves of the low-frequency band and the high-frequency band, including: When the reference frequency is selected at a low frequency, the inter-terminal equivalent capacitance is calculated based on the inter-terminal impedance of the transformer winding, and then the initial value of the segmented parallel capacitance is calculated based on the inter-terminal equivalent capacitance of the transformer winding before the pre-fault condition. The initial value is: ； Among them, C g is the initial value of the segmented parallel capacitance, C L1-0 is the equivalent capacitance between terminals of the transformer winding before the pre-fault condition; N is the order of the ladder network model; When a reference frequency is selected in a high frequency band, based on a star-to-delta equivalent transformation method, a ratio of the end-to-end equivalent capacitance before pre-fault to the segmented parallel capacitance is calculated at the reference frequency, and an initial value of the segmented series capacitance is calculated based on the ratio.

3. The transformer winding turn-to-turn fault location method according to claim 1, wherein: The inter-turn fault factor in the pre-fault state is: ； Among them, ITFF pre (i) is the inter-turn fault factor of each transformer winding in the transformer ladder network model under the pre-fault state; K i is the constant of the i-th transformer winding in the pre-fault state; a1(i), a2(i), b1(i), b2(i) are the coefficients of the i-th transformer winding in the pre-fault state; C si is the segmented series capacitance value of the i-th transformer winding; ； ； ； ； in, , ; C 2i 、C 22i are the total series equivalent capacitance and parallel equivalent capacitance of segments i+1 to N, respectively; C 1i 、C 11i are the total series equivalent capacitance and parallel equivalent capacitance of segments 1 to i-1, respectively.

4. The transformer winding turn-to-turn fault location method according to claim 1, wherein: The inter-turn fault factor under the fault state is: ； Among them, ITFF post is the inter-turn fault factor under the fault state; C 1-0 、C 2-0 is the equivalent capacitance between terminals measured before the pre-fault condition when the reference frequency is selected in the high frequency band; 、 It is the equivalent capacitance between terminals measured when the reference frequency is selected in the high frequency band after a fault occurs.

5. The transformer winding turn-to-turn fault location method according to claim 1, wherein: When the deviation between the inter-turn fault factor of the i-th section transformer winding in the pre-fault state and the inter-turn fault factor in the fault state is less than 0, if the inter-turn fault factor in the fault state is less than 0, the fault occurs in the i-th section transformer winding; if the inter-turn fault factor in the fault state is greater than 0, the fault occurs in the i-1-th section transformer winding.

6. A transformer winding inter-turn fault simulation device, which simulates the fault of a transformer winding that is located by using the transformer winding inter-turn fault location method according to any one of claims 1 to 5, characterized in that: include: Vertical lifting mechanism; a supporting structure slidably connected to the vertical lifting mechanism in a vertical direction; A horizontal adjustment mechanism is slidably connected to the support structure in the horizontal direction through a screw-nut pair, and a short-circuit actuator is provided at one end of the horizontal adjustment mechanism away from the support structure; The short-circuit actuator is used to clamp the selected turns of the transformer and establish a short-circuit loop between the selected turns of the transformer; And, a signal acquisition system is used to perform fault detection on selected turns of the transformer.

7. The transformer winding inter-turn fault simulation device according to claim 6, characterized in that: The vertical lifting mechanism includes a vertical lift column, a slide chute, a slider, a transmission gear, a rack guide rail, a first stepper motor and a transmission threaded rod; The slide groove is provided on the outer surface of the vertical lift column, and the slider is embedded in the slide groove; The rack guide rail is provided on the outer surface of the vertical lift column and meshes with the transmission gear; One end of the transmission threaded rod is connected to the transmission gear, and the other end is connected to the output shaft of the first stepper motor.

8. The transformer winding inter-turn fault simulation device according to claim 7, characterized in that: The support structure includes a support wall, a support platform and a fixing plate; The support wall is slidably connected to the slide groove via the slider; The support platform is fixedly connected to the top of the support wall through the fixing plate, and the support platform is used to carry the horizontal adjustment mechanism.

9. The transformer winding inter-turn fault simulation device according to claim 8, characterized in that: The horizontal adjustment mechanism includes a second stepping motor, a telescopic cylinder, a gear set, a trapezoidal lead screw, a trapezoidal nut and a connector; The second stepper motor is fixed on the supporting platform; The driving wheel in the gear set is connected to the output shaft of the second stepping motor, and the driven wheel in the gear set is key-connected to the trapezoidal lead screw; The trapezoidal nut is sleeved on the trapezoidal lead screw and forms a threaded fit with the trapezoidal lead screw; One end of the telescopic cylinder is connected to the trapezoidal nut, and the other end is connected to one end of the connector; the other end of the connector is connected to the short-circuit actuator.

10. The transformer winding inter-turn fault simulation device according to claim 9, characterized in that: The short-circuit actuator includes: a metal clamp, a hydraulic device and a loop wire; One end of the metal clamp is connected to the connector via the hydraulic device; One end of the loop wire is electrically connected to the metal clamp, and the other end is electrically connected to the selected turn winding of the transformer.

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