A three-phase transformer winding inter-turn short circuit simulation device and fault identification method

Abstract

The application discloses a kind of three-phase transformer winding interturn short circuit simulation device and fault identification method using fault detection index, realize the interturn short circuit fault simulation of three-phase transformer winding at different positions by motor drive gear transmission device, further by current transformer, the real-time current flowing through winding is collected, coefficient matrix is solved unknown quantity vector by constructing measurement matrix, further calculate fault detection index, finally whether interturn short circuit fault occurs is judged using fault detection index, with the advantages of high sensitivity, good accuracy, strong field applicability, transformer winding interturn short circuit fault can be found in time.

Description

Technical Field

[0001] This application relates to the field of power equipment fault diagnosis technology, specifically to a three-phase transformer winding inter-turn short circuit simulation device and fault identification method. Background Technology

[0002] Three-phase transformers, as key equipment in power systems, commonly experience inter-turn short-circuit faults in their windings. These faults can lead to localized overheating of the transformer, causing more serious accidents and threatening the safe and stable operation of the power system. Therefore, timely detection of inter-turn short-circuit faults in transformer windings is crucial for ensuring the safe operation and timely maintenance of transformers. Currently, traditional fault diagnosis methods for transformer inter-turn short circuits largely rely on the transformer's operating state before the fault occurs. These methods are not sensitive enough in fault detection, involve large computational loads, and have poor field applicability. Therefore, this invention proposes a method that uses a mechanical device to simulate inter-turn short-circuit faults in three-phase transformer windings and determines whether an inter-turn short circuit has occurred by calculating fault detection indicators. Summary of the Invention

[0003] The purpose of this invention is to provide a three-phase transformer winding inter-turn short circuit simulation device and fault identification method, which simulates inter-turn short circuit faults in three-phase transformer windings, collects winding current samples at different times during transformer operation, and calculates fault detection indicators to achieve inter-turn short circuit fault identification.

[0004] To achieve the above technical objectives, this invention provides a three-phase transformer winding inter-turn short-circuit fault simulation device. This device uses a non-contact mechanical device to simulate inter-turn short-circuit faults and includes: a three-phase winding core, a mechanical device support platform, an A-phase primary winding, an A-phase secondary winding, a B-phase primary winding, a B-phase secondary winding, a C-phase primary winding, a C-phase secondary winding, a drive gear connected to a first-stage stepper motor via an output shaft, a first-stage reduction gear meshing with the drive gear, a transmission gear connected to the first-stage reduction gear via a transmission shaft, a second-stage reduction gear meshing with the transmission gear, a fixed shaft, an external gear meshing with the second-stage reduction gear, and a shaft tightly connected to the external gear. The system comprises: an internal gear that maintains the same rotational angular velocity; a cylindrical hollow working platform; a first spur gear located above the working platform and meshing with the internal gear; a bearing a connecting the first spur gear and a primary rotating gear a; a secondary rotating gear a meshing with the primary rotating gear a; a bearing b connecting the secondary rotating gear a and a first lifting gear; a first fixed column; a first lifting device; a second spur gear located symmetrically to the axis of the first lifting spur gear and meshing with the internal gear; a bearing c connecting the second spur gear and the primary rotating gear b; a secondary rotating gear b meshing with the primary rotating gear a; a bearing d connecting the secondary rotating gear b and the second lifting gear; a second fixed column; and a second lifting device.

[0005] The second lifting device includes: a lifting shell, a hollow cylinder that can slide freely in several vertical directions, a rack and pinion guide rail that is tightly connected to the hollow cylinder, a rotary motor a, a support platform, a second stepper motor, an electric push rod, a hydraulic device, a metal gripper a, and a metal wire a.

[0006] The difference between the first lifting device and the second lifting device is that the first lifting device also includes a short-range micro lifting platform driven by a rotary motor b.

[0007] This invention also provides a method for identifying inter-turn short-circuit faults in three-phase transformer windings, comprising the following steps:

[0008] Step 1: Simulate an inter-turn short-circuit fault in a three-phase transformer winding;

[0009] Step 2: Identify inter-turn short-circuit faults in the three-phase transformer windings.

[0010] Further, step one includes:

[0011] 1) Install and fix the three-phase windings of the transformer and the gear transmission mechanism, and place the upper surfaces of the first and second lifting devices on the same plane as the initial position;

[0012] 2) Control the first stepper motor to drive the drive gear to rotate, which in turn drives the first stage reduction gear and transmission gear to rotate, and then drives the second stage reduction gear to rotate, thereby reducing the speed and increasing the torque. This process further drives the external gear and internal gear transmission, and then drives the second spur gear and the first stage rotating gear b, and then drives the second stage rotating gear b and the second lifting gear, which in turn drives the second lifting device to rise to the designated position.

[0013] 3) Control the rotary motor a to rotate, driving the support platform to rotate until the metal gripper a is directly opposite the primary winding of the transformer;

[0014] 4) Control the second stepper motor to drive the electric push rod to move horizontally until the metal gripper a is located between two turns of the primary winding of the transformer;

[0015] 5) Control the hydraulic device to open the metal jaw a until the metal jaw a contacts the two turns of the coil winding, forming a short circuit loop between the coil contact point, the metal jaw a, and the metal wire a.

[0016] 6) Control the rotation of the rotary motor b to drive the short-stroke micro lifting platform to rise vertically until the gap between the metal gripper b and the other two adjacent coils in the two coils of 4) is horizontal. According to the process control in 3) to 5), the first lifting device forms another coil contact point, metal gripper b, and metal wire b short circuit circuit.

[0017] 7) Repeat steps 2) to 6) to simulate inter-turn short-circuit faults at multiple locations on the primary winding of the transformer.

[0018] Furthermore, step two includes:

[0019] 1) Determine the number of turns in the primary winding, the number of turns in the secondary winding, and the magnetic reluctance of the three-phase core cross-section for simulating inter-turn short-circuit faults in the three-phase transformer.

[0020] 2) Set the sampling frequency of the host computer to 1KHz, collect the winding current through 6 current transformers connected in series on the primary and secondary windings of the three-phase transformer, and input the current to the host computer through an analog-to-digital converter (A / D) to realize the collection of n sets of primary and secondary winding currents of the three-phase transformer.

[0021] 3) Calculate the coefficient matrix M for solving the fault detection index and the measurement matrix N composed of the sampled current signals:

[0022]

[0023] Where: R a R b R c These are the magnetic reluctance of the core sections of the three-phase windings A, B, and C of the transformer, respectively, and N. p The number of turns in the primary winding of the transformer, N s n is the number of secondary turns of the transformer winding, n is the number of samples, and i is the number of secondary turns of the transformer winding. pa i pb i pc These represent the currents flowing through the primary windings of phases A, B, and C of a three-phase transformer, respectively, and i sa i sb i sc These are the currents flowing through the secondary windings of phases A, B, and C of a three-phase transformer, respectively.

[0024] 4) Calculate the unknown vector X that reflects the fault detection indicators:

[0025] X = (M T M) -1 N

[0026]

[0027] Where N f For short-circuit turns, I f The effective value of the induced current at the location where an inter-turn short circuit occurs;

[0028] 5) Select an appropriate fault detection threshold (Δ), calculate the fault detection index a based on the unknown vector X value in 4), and determine whether an inter-turn short-circuit fault has occurred in the transformer winding:

[0029]

[0030] If |a|>Δ, then an inter-turn short circuit fault occurs in the transformer winding.

[0031] The beneficial effects of this invention are as follows: it uses a non-contact mechanical device to simulate a short-circuit fault between turns of a three-phase transformer winding, uses a current transformer to collect transformer winding current information, and uses fault detection indicators to determine whether a short-circuit fault between turns of the winding has occurred, which can more sensitively and accurately identify the short-circuit fault between turns of the winding. Attached Figure Description

[0032] Figure 1 This is a diagram of the three-phase transformer winding inter-turn short circuit simulation device of the present invention;

[0033] Figure 2 This is a diagram of the mechanical gear transmission device of the present invention;

[0034] Figure 3 This is a schematic diagram of an elevator system.

[0035] Figure 4 This is a flowchart of a method for identifying inter-turn short-circuit faults in a three-phase transformer winding according to the present invention. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings:

[0037] like Figure 1 , Figure 2 , Figure 3As shown, a three-phase transformer winding inter-turn short-circuit fault simulation device of the present invention includes, in the figure, a three-phase winding core 1, a mechanical device support platform 2, an A-phase primary winding 3, an A-phase secondary winding 4, a B-phase primary winding 5, a B-phase secondary winding 6, a C-phase primary winding 7, and a C-phase secondary winding 8, a drive gear 11 connected to a first stepper motor 9 via an output shaft 10, a first-stage reduction gear 12 meshing with the drive gear, a transmission gear 14 connected to the first-stage reduction gear via a transmission shaft 13, a second-stage reduction gear 15 meshing with the transmission gear, a fixed shaft 16, an external gear 17 meshing with the second-stage reduction gear, an internal gear 18 tightly connected to the external gear and maintaining the same rotational angular velocity, a cylindrical hollow structure working platform 19, a first spur gear 20 located above the working platform and meshing with the internal gear, a bearing a22 connecting the first spur gear and the first-stage rotating gear a21, and a bearing a22 connected to the first-stage rotating gear a21. The components include: a second-stage rotating gear a23, a bearing b25 connecting the second-stage rotating gear a and the first lifting gear 24, a first fixed column 26, a first lifting device 27, a second spur gear 28 located symmetrically positioned at the axis of the first lifting spur gear and meshing with the internal gear, a bearing c30 connecting the second spur gear and the first-stage rotating gear b29, a second-stage rotating gear b31 meshing with the first-stage rotating gear a, a bearing d33 connecting the second-stage rotating gear b and the second lifting gear 32, a second fixed column 34, a second lifting device 35, a lifting housing 36, a hollow cylinder 37 capable of sliding freely in several vertical directions, a rack guide rail 38 tightly connected to the hollow cylinder, a rotary motor a39, a support platform 40, a second stepper motor 41, an electric push rod 42, a hydraulic device 43, a metal gripper a44, a metal wire a45, a short-range micro lifting platform 47 driven by the rotary motor b46, a metal gripper b48, and a metal wire b49.

[0038] like Figure 4 As shown, the present invention provides a method for identifying inter-turn short-circuit faults in three-phase transformer windings. This method uses a non-contact mechanical device to simulate an inter-turn short-circuit fault in the three-phase transformer windings, collects transformer winding current information using a current transformer, and determines whether an inter-turn short-circuit fault has occurred based on fault detection indicators. Specifically, the method includes the following steps:

[0039] Step 1: Simulate an inter-turn short-circuit fault in a three-phase transformer winding, including:

[0040] 1) Install and fix the three-phase windings of the transformer and the gear transmission mechanism, and place the upper surfaces of the first lifting device 27 and the second lifting device 35 on the same plane as the initial position;

[0041] 2) Control the first stepper motor 9 to drive the drive gear 11 to rotate, which in turn drives the first stage reduction gear 12 and the transmission gear 13 to rotate, and further drives the second stage reduction gear 15 to rotate, thereby reducing the speed and increasing the torque. This further drives the external gear 17 and the internal gear 18 to drive the transmission, and further drives the second spur gear 28 and the first stage rotating gear b29, and further drives the second stage rotating gear b31 and the second lifting gear 32, and further drives the second lifting device 35 to rise to the designated position.

[0042] 3) Control the rotary motor a39 to rotate, driving the support platform 40 to rotate until the metal gripper a44 is directly opposite the primary winding of the transformer;

[0043] 4) Control the second stepper motor 41 to drive the electric push rod 42 to move horizontally until the metal gripper a is located between two turns of the primary winding of the transformer;

[0044] 5) Control the hydraulic device 43 to open the metal jaw a until the metal jaw a contacts the two turns of the coil winding, forming a short circuit loop between the coil contact point, the metal jaw a, and the metal wire b45;

[0045] 6) Control the rotary motor b46 to rotate, driving the short-stroke micro lifting platform 47 to rise vertically until the gap between the metal gripper b48 and the other two coils adjacent to the two coils in 4) is horizontal. According to the process control in 3) to 5), the first lifting device forms another coil contact point, metal gripper b, and metal wire b49 short circuit circuit.

[0046] 7) Repeat steps 2) to 6) to simulate inter-turn short-circuit faults at multiple locations on the primary winding of the transformer.

[0047] Step Two: Conduct inter-turn short-circuit fault identification in the three-phase transformer windings, including:

[0048] 1) Determine the number of turns in the primary winding, the number of turns in the secondary winding, and the magnetic reluctance of the three-phase core cross-section for simulating inter-turn short-circuit faults in the three-phase transformer.

[0049] 2) Set the sampling frequency of the host computer to 1KHz, collect the winding current through 6 current transformers connected in series on the primary and secondary windings of the three-phase transformer, and input the current to the host computer through an analog-to-digital converter (A / D) to realize the collection of n sets of primary and secondary winding currents of the three-phase transformer.

[0050] 3) Calculate the coefficient matrix M for solving the fault detection index and the measurement matrix N composed of the sampled current signals:

[0051]

[0052] Where: R a R b Rc These are the magnetic reluctance of the core sections of the three-phase windings A, B, and C of the transformer, respectively, and N. p The number of turns in the primary winding of the transformer, N s n is the number of secondary turns of the transformer winding, n is the number of samples, and i is the number of secondary turns of the transformer winding. pa i pb i pc These represent the currents flowing through the primary windings of phases A, B, and C of a three-phase transformer, respectively, and i sa i sb i sc These are the currents flowing through the secondary windings of phases A, B, and C of a three-phase transformer, respectively.

[0053] 4) Calculate the unknown vector X that reflects the fault detection indicators:

[0054] X = (M T M) -1 N

[0055]

[0056] Where N f For short-circuit turns, I f The effective value of the induced current at the location where an inter-turn short circuit occurs;

[0057] 5) Select an appropriate fault detection threshold (Δ), calculate the fault detection index a based on the unknown vector X value in 4), and determine whether an inter-turn short-circuit fault has occurred in the transformer winding:

[0058]

[0059] If |a|>Δ, then an inter-turn short circuit fault occurs in the transformer winding.

Claims

1. A device for simulating inter-turn short-circuit faults in three-phase transformer windings, characterized in that: A mechanical device is used to simulate a short circuit between turns of a three-phase transformer winding, including a three-phase winding core (1), a mechanical device support platform (2), an A-phase primary winding (3), an A-phase secondary winding (4), a B-phase primary winding (5), a B-phase secondary winding (6), a C-phase primary winding (7), a C-phase secondary winding (8), a drive gear (11) connected to a first stepper motor (9) via an output shaft (10), a first-stage reduction gear (12) meshing with the drive gear, a transmission gear (14) connected to the first-stage reduction gear via a transmission shaft (13), a second-stage reduction gear (15) meshing with the transmission gear, a fixed shaft (16), an external gear (17) meshing with the second-stage reduction gear, an internal gear (18) tightly connected to the external gear and maintaining the same rotational angular velocity, and a cylindrical hollow junction. The structure includes a working platform (19), a first spur gear (20) located above the working platform and meshing with the internal gear, a bearing a (22) connecting the first spur gear and the first-stage rotating gear a (21), a second-stage rotating gear a (23) meshing with the first-stage rotating gear a, a bearing b (25) connecting the second-stage rotating gear a and the first lifting gear (24), a first fixed column (26), a first lifting device (27), a second spur gear (28) located symmetrically positioned at the axis of the first lifting spur gear and meshing with the internal gear, a bearing c (30) connecting the second spur gear and the first-stage rotating gear b (29), a second-stage rotating gear b (31) meshing with the first-stage rotating gear b, a bearing d (33) connecting the second-stage rotating gear b and the second lifting gear (32), a second fixed column (34), and a second lifting device (35). The second lifting device includes: a lifting shell (36), a hollow cylinder (37) that can slide freely in the vertical direction, a rack and pinion guide rail (38) that is tightly connected to the hollow cylinder, a rotary motor a (39), a support platform (40), a second stepper motor (41), an electric push rod (42), a hydraulic device (43), a metal gripper a (44), and a metal wire a (45). The first lifting device, relative to the second lifting device, further includes a short-range micro lifting platform (47) driven by a rotary motor b (46).

2. The three-phase transformer winding inter-turn short-circuit fault simulation device according to claim 1, characterized in that, The output shaft, transmission shaft, and fixed shaft are connected to the mechanical device support platform. Bearing a, the first fixed column, bearing c, and the second fixed column are connected to the working platform to maintain the relative fixation of the spatial position of the mechanical gears.

3. A method for identifying inter-turn short-circuit faults in a three-phase transformer winding, characterized in that, Includes the following steps: Step 1: Simulate an inter-turn short-circuit fault in a three-phase transformer winding; Step 2: Conduct inter-turn short-circuit fault identification in the three-phase transformer windings; The first step includes: 1) Install the three-phase windings of the transformer and the gear transmission mechanism and fix them. Place the upper surfaces of the first elevator device (27) and the second elevator device (35) on the same plane as the initial position. 2) Control the first stepper motor (9) to drive the drive gear (11) to rotate, which in turn drives the first stage reduction gear (12) and transmission gear (14) to rotate, which in turn drives the second stage reduction gear (15) to rotate, thereby reducing the speed and increasing the torque. This further drives the external gear (17) and internal gear (18) to drive, which in turn drives the second spur gear (28) and the first stage rotating gear b (29), which in turn drives the second stage rotating gear b (31) and the second lifting gear (32), which in turn drives the second lifting device (35) to rise to the designated position. 3) Control the rotary motor a(39) to rotate, driving the support platform (40) to rotate until the metal gripper a(44) is directly opposite the primary winding of the transformer; 4) Control the second stepper motor (41) to drive the electric push rod (42) to move horizontally until the metal gripper a is located between two turns of the primary winding of the transformer; 5) Control the hydraulic device (43) to open the metal jaw a until the metal jaw a contacts the two turns of the coil of the winding, forming a short circuit loop of the coil contact point, the metal jaw a, and the metal wire a (45); 6) Control the rotary motor b (46) to rotate, drive the short-range micro lifting platform (47) to rise vertically to the level of the gap between the metal gripper b (48) and the two adjacent coils of the two coils described in 4), and control the first lifting device to form another coil contact point, metal gripper b, and metal wire b (49) short circuit circuit according to the process in 3) to 5). 7) Repeat steps 2) to 6) to simulate inter-turn short circuit faults at multiple locations on the primary winding of the transformer; Step two includes: 1) Determine the number of turns in the primary winding, the number of turns in the secondary winding, and the magnetic reluctance of the three-phase core cross-section for simulating inter-turn short-circuit faults in the three-phase transformer. 2) Set the sampling frequency of the host computer to 1KHz, collect the winding current through 6 current transformers connected in series on the primary and secondary windings of the three-phase transformer, and input the current to the host computer through an analog-to-digital converter to realize the collection of n sets of primary and secondary winding currents of the three-phase transformer. 3) Calculate the coefficient matrix M for solving the fault detection index and the measurement matrix N composed of the sampled current signals: Where: R a R b R c These are the magnetic reluctance of the core sections of the three-phase windings A, B, and C of the transformer, respectively, and N. p The number of turns in the primary winding of the transformer, N s n is the number of secondary turns of the transformer winding, n is the number of samples, and i is the number of secondary turns of the transformer winding. pa i pb i pc These represent the currents flowing through the primary windings of phases A, B, and C of a three-phase transformer, respectively, and i sa i sb i sc These are the currents flowing through the secondary windings of phases A, B, and C of a three-phase transformer, respectively. 4) Calculate the unknown vector X that reflects the fault detection indicators: Where N f For short-circuit turns, I f The effective value of the induced current at the location where an inter-turn short circuit occurs; 5) Select an appropriate fault detection threshold Δ, calculate the fault detection index a based on the unknown vector X value in 4), and determine whether an inter-turn short-circuit fault has occurred in the transformer winding: If |a|>Δ, then an inter-turn short circuit fault occurs in the transformer winding.

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