Power transformer turn-to-turn short circuit fault positioning method and system based on magnetic flux leakage distribution

Abstract

The invention discloses a power transformer turn-to-turn short circuit fault positioning method and system based on magnetic flux leakage distribution. The method comprises the following steps: acquiring the radial magnetic field intensity inside a power transformer; based on the obtained radial magnetic field intensity, the short circuit fault occurrence condition is judged by adopting a difference value method; when a short-circuit fault occurs, the position of the short-circuit fault point is positioned by using the position of the zero crossing point of the radial magnetic field intensity. According to the invention, the improved optical fiber sensor is used for collecting the magnetic flux leakage distribution in the power transformer, and then the amplitude and phase characteristics of the magnetic flux leakage are obtained through Fourier transform and an interpolation method. And rapid monitoring and interval positioning of the turn-to-turn short circuit fault of the power transformer are realized by monitoring the internal magnetic leakage amplitude and phase characteristics of the power transformer.

Description

Technical Field

[0001] The invention belongs to the technical field of power transformer detection, and in particular relates to a method and system for locating inter-turn short-circuit faults of power transformers based on magnetic flux leakage distribution. Background Art

[0002] Power transformers are important equipment in power systems. The most important equipment for power systems to achieve voltage rise and fall is power transformers. Therefore, power transformers are the core equipment for voltage conversion and power transmission in power systems. Therefore, transformer failure will seriously affect the reliability of power supply and the normal operation of the system. According to previous data statistics, about 70% to 80% of transformer failures are inter-turn failures of windings. One of the more important problems is inter-turn short circuit of windings. Inter-turn short circuit is the direct contact of two or more turns of coils that are close to each other due to the destruction of the insulation layer. When the transformer is pressurized and shaped during the production process, excessive force will cause damage to the coil insulation. Long-term operation is prone to insulation aging. The transformer will have an inter-turn short circuit failure when overcurrent or overvoltage occurs. The probability of damage to the transformer after a short circuit increases significantly, and transformer damage accidents caused by transformer short circuits account for 50% of the total accident ratio. In addition, after an internal fault occurs in a power transformer, there is a high probability that an explosion and fire accident will occur, causing serious accidents and property losses. Therefore, it is of great significance to develop an effective method for monitoring and locating inter-turn short circuit faults in power transformers.

[0003] At present, current differential protection and gas protection are mainly used as the main protection of transformers in engineering, but these protection methods have various shortcomings when facing inter-turn short circuit. Differential protection is the main protection of transformers, and the main faults it responds to are inter-phase short circuit of transformer internal windings, single-phase serious inter-turn short circuit and other conditions. When a slight inter-turn short circuit occurs in the transformer, the current in the short-circuited turn is large and destructive, but the characteristic quantity reflected on the differential current between phases has only a slight change, so it is difficult for differential protection to effectively protect the inter-turn short circuit fault of power transformers. In addition, although gas protection is for internal faults of transformers. However, the judgment basis of heavy gas protection is the oil speed in the oil pillow connecting pipe, and the inter-turn fault requires a large electric power to drive the oil flow rate to the set value, and it takes a certain amount of time for the oil flow to accelerate to the set value, and its action time will be affected by factors such as the location of the fault point, gas production and production rate, and the viscosity of the insulating oil. Therefore, although heavy gas protection can protect the inter-turn short circuit fault of power transformers, its sensitivity and rapidity are insufficient. Therefore, it is of great significance to develop a method that can quickly protect against turn-to-turn short-circuit faults. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for locating inter-turn short-circuit faults of power transformers based on leakage magnetic distribution in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problem of how to quickly and accurately diagnose and locate inter-turn short-circuit faults of power transformers.

[0005] The present invention adopts the following technical solutions: A method for locating a turn-to-turn short-circuit fault of a power transformer based on magnetic flux leakage distribution comprises the following steps: S1. Obtain the radial magnetic field strength inside the power transformer; S2. Based on the radial magnetic field strength obtained in step S1, a difference method is used to determine the occurrence of a short circuit fault; S3. When a short circuit fault occurs, the position of the short circuit fault point is located by using the position of the zero-crossing point of the radial magnetic field intensity.

[0006] Preferably, in step S1, magnetic field sensors are used to obtain the radial magnetic field strength inside the power transformer, and the magnetic field sensors are arranged on the box wall of the power transformer with equal potential from top to bottom; and the magnetic field sensors at the top and bottom are high-frequency sensors.

[0007] Preferably, the magnetic field sensor is an optical fiber magnetic field sensor, which is horizontally arranged along the radial direction of the wall of the power transformer box to capture the leakage magnetic component.

[0008] Preferably, in the radial direction, the optical fiber magnetic field sensor is 100-1000 mm away from the outermost side of the high-voltage winding, and is 1-100 mm away from the inner wall of the transformer housing.

[0009] Preferably, the response frequency of the high-frequency sensor is 150-250 Hz.

[0010] Preferably, in step S2, when the changed magnetic field difference T2 is less than the magnetic field difference before the change At T1, it is determined that a turn-to-turn short circuit fault has occurred in the power transformer.

[0011] Preferably, the magnetic field strength at the lowest point is T1, and the magnetic field strength at the highest point is T2; then T=T2-T1, get the magnetic field difference before the change T1 and the difference between the magnetic field after the change T2.

[0012] Preferably, in step S3, the transformer winding is divided into four parts according to the inter-turn short-circuit magnetic field distribution curves at different points, so as to locate the position of the short-circuit fault point.

[0013] Preferably, the short-path magnetic field distribution curves between turns at different points are 0%~10% height, 20%~30% height, 45%~55% height, 70%~80% height and 90%~100% height of the winding, respectively.

[0014] In a second aspect, an embodiment of the present invention provides a system for locating inter-turn short-circuit faults of power transformers based on magnetic flux leakage distribution, characterized in that it includes: Data module, obtaining radial magnetic field strength inside the power transformer; The judgment module uses a difference method to judge the occurrence of a short circuit fault based on the radial magnetic field strength; The positioning module locates the short-circuit fault point by using the position of the zero-crossing point of the radial magnetic field intensity when a short-circuit fault occurs.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The method for locating inter-turn short-circuit faults of power transformers based on leakage magnetic distribution shows that when an inter-turn short-circuit fault occurs in a power transformer, the internal leakage magnetic amplitude and phase of the transformer will change significantly, and the change of leakage magnetic related parameters has a strong correlation with the location of the inter-turn short-circuit fault. This provides the possibility for monitoring and rapid interval positioning of transformer inter-turn short-circuit faults.

[0016] Furthermore, the equipotential arrangement of the magnetic field sensor and the box wall of the power transformer can reduce the influence of the electric field inside the transformer on the magnetic flux leakage sensor, ensuring the safe operation of the sensor inside the power transformer.

[0017] Furthermore, the optical fiber magnetic field sensor is arranged horizontally along the radial direction of the power transformer box wall. When a turn-to-turn short circuit fault occurs in the power transformer, the radial magnetic field inside the transformer changes most significantly. Therefore, monitoring and interval positioning of turn-to-turn short circuit faults by measuring the radial magnetic field strength has the best sensitivity.

[0018] Furthermore, in the radial direction, the optical fiber magnetic field sensor is 100-1000 mm away from the outermost side of the high-voltage winding and 1-100 mm away from the inner wall of the transformer housing. This allows the sensor to be as far away from the transformer winding as possible, reducing the mutual influence between the magnetic field sensor and the transformer, and ensuring the insulation safety of the transformer and the accuracy of the magnetic field sensor.

[0019] Furthermore, the response frequency of the high-frequency sensor is 150~250Hz. When a turn-to-turn short-circuit fault occurs in the transformer, the high-frequency component in this frequency range accounts for a large proportion, and the transformer turn-to-turn short-circuit fault can be monitored more accurately at a lower cost.

[0020] Furthermore, when the magnetic field difference after the change T2 is less than the magnetic field difference before the change When T1, it can be determined that a turn-to-turn short circuit fault has occurred in the power transformer. When a turn-to-turn short circuit fault occurs, a reverse magnetic field will be generated, which will cause the magnetic field difference to T becomes smaller.

[0021] Furthermore, the transformer winding is divided into four parts according to the inter-turn short-circuit magnetic field distribution curves at different points, and the position of the short-circuit fault point is located. The relevant parameters of the leakage magnetic phase in the transformer have a certain correlation with the position of the inter-turn short-circuit fault, so the position interval of the inter-turn short-circuit fault can be determined by measuring the transformer-specific leakage magnetic curve.

[0022] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0023] In summary, the present invention uses an improved optical fiber sensor to collect the leakage magnetic distribution inside the power transformer, and then obtains the amplitude and phase characteristics of the leakage magnetic field through Fourier transform and interpolation method, and then realizes the rapid monitoring and interval positioning of the inter-turn short-circuit fault of the power transformer by monitoring the leakage magnetic amplitude and phase characteristics inside the power transformer.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the sensor layout diagram; Figure 2 is the radial magnetic field distribution under normal working conditions; Figure 3 This is the radial magnetic field distribution after the 52nd turn is short-circuited; Figure 4 The short path magnetic field distribution between turns at different positions; Figure 5 It is the fault location interval diagram; Figure 6 Schematic diagram of radial magnetic field distribution of Example 1 of the present invention; Figure 7 Schematic diagram of radial magnetic field distribution of Example 2 of the present invention.

[0026] Figure 8 A schematic diagram of a computer device provided by an embodiment of the present invention; Fig. 9 A block diagram of an electronic device provided according to an embodiment of the present invention; Fig.10 This is the layout diagram of the magnetic sensor installation position; Fig.11 It is a comparison diagram of radial magnetic field components; Fig.12 It is a schematic diagram of the comparison of axial magnetic field components; Fig.13 This is a schematic diagram of the power transformer of Example 1. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0029] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0030] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0031] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0032] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0033] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0034] There is a close connection between the electric field and the magnetic field, and they are an integral relationship. Therefore, when a short-circuit fault occurs in the power transformer, the spatial distribution of the leakage magnetic field around the power transformer winding is affected by the winding current and the fault location, and shows a certain regularity. When the proportion of short-circuit turns is small, the leakage magnetic field change is still significant and the sensitivity is very high.

[0035] The present invention provides a method for locating a turn-to-turn short-circuit fault of a power transformer based on magnetic flux leakage distribution, comprising the following steps: S1. Place a magnetic field sensor inside the power transformer to obtain the magnetic field strength; Firstly, because the monitoring judgment basis of the present invention is the change of leakage magnetic flux, a magnetic field sensor should be placed inside the power transformer to obtain the change of magnetic field intensity.

[0036] See also Figure 1 The three layers of windings of the power transformer are low voltage, medium voltage and high voltage windings from the inside to the outside. The highest winding of the high voltage winding is the 104th winding, with a height of 3010mm; the lowest winding of the high voltage winding is the 1st winding, with a height of 890mm.

[0037] See also Fig.10 In order to find the position with the largest rate of change of leakage magnetic parameters when different faults occur, that is, the position with the highest external sensitivity, it is concluded that there are four installation positions for magnetic sensors according to the structure of the power transformer.

[0038] Assuming that a turn-to-turn short circuit occurs at the 52nd turn in the power transformer, simulation and experimental verification are performed on the above four positions.

[0039] From the simulation and experimental results, it can be seen that when the power transformer has a turn-to-turn short circuit, the magnetic field distribution at the above four positions will change significantly, and all have high sensitivity. However, considering the difficulty of sensor installation and reducing the impact of the sensor on the power transformer, the four positions are the best installation positions.

[0040] After determining the sensor installation position, you also need to determine the sensor installation direction. Because the magnetic field strength is a three-dimensional quantity in space, but the magnetic field sensor can only measure the component in one direction. Because there is no leakage magnetic distribution in the tangential direction, the radial and axial magnetic field strength components are tested at four locations. The results are as follows: Fig.11 and Fig.12 shown.

[0041] It can be seen from the simulation and experimental results that when a turn-to-turn short circuit occurs in the power transformer, the magnetic field in the radial direction at position 4 has the best external response sensitivity.

[0042] Therefore, the sensor is positioned at position 4, and the orientation of measuring the magnetic field strength is radial. The final arrangement of the magnetic sensor is as follows: Figure 1 shown.

[0043] If the sensor is based on the height of the winding, the height of its arrangement is shown in the following table:

[0044] The sensors arranged at the above positions are mainly used to detect the occurrence of inter-turn short circuits and locate the positions of inter-turn short circuits, so they are steady-state sensors with a response frequency of 50 Hz, a maximum sensing range of 3 T, and a resolution of 0.1 mT.

[0045] However, when a turn-to-turn short-circuit fault occurs in a power transformer, it may also involve phenomena such as the reignition of the turn-to-turn arc, so its short-circuit resistance is constantly changing, causing the turn-to-turn short-circuit current to also show irregular changes. Therefore, when the turn-to-turn arc is discontinuous and reignited, the magnetic field change will have a high-frequency component. In order to monitor this change, a high-frequency sensor is installed at the position of sensors 1 and 9. Its response frequency is between 150 and 250 Hz, and it is mainly used to monitor the third and fifth harmonics.

[0046] According to the test and simulation results, the magnetic field sensor is placed near the inner wall of the power transformer, and then the radial magnetic field strength is measured, achieving better results.

[0047] Preferably, in the embodiment, an optical fiber magnetic field sensor is used to capture the leakage magnetic component. The optical fiber magnetic field sensor has a cylindrical metal shell of φ10mm×60mm; the optical fiber magnetic field sensor is arranged at the same potential as the wall of the power transformer box, so it is necessary to establish a metal connection with the inner wall of the transformer. At the same time, the radial magnetic field component is measured, so the optical fiber magnetic field sensor is arranged horizontally in the radial direction; in the radial direction, it is 100~1000mm away from the outermost side of the high-voltage winding and 1~100mm away from the inner wall of the transformer shell.

[0048] See also Figure 2 , when the power transformer works under normal conditions, the radial magnetic field distribution at the measurement position is obtained by testing. As can be seen from the figure, when the power transformer works normally, its leakage flux is symmetrical in value and remains symmetrical on the axis parallel to the center of the winding.

[0049] See also Figure 3 When a turn-to-turn short circuit occurs in the power transformer, the radial magnetic field can be tested again to obtain the radial magnetic field distribution at the measurement position. As can be seen from the figure, when a turn-to-turn short circuit occurs in the power transformer, its radial magnetic field distribution changes significantly.

[0050] In order to verify the universality of this result, turn-to-turn short-circuit fault points were set at different locations, and the distribution of the radial magnetic field was measured. The results are as follows: Figure 4 shown.

[0051] from Figure 4 It can be seen that no matter where the inter-turn short circuit occurs, from the highest coil to the lowest coil, and any coil in the middle, even if only one turn of the coil is short-circuited, the radial magnetic field distribution will change significantly.

[0052] S2. Turn-to-turn fault monitoring and judgment; In the present invention, the difference method is mainly used to determine whether a short circuit fault occurs; Because the inter-turn short-circuit current and the normal current are inversely related, when the normal current is positive, once a short-circuit current occurs, the difference will become smaller.

[0053] Assume that the magnetic field strength at the lowest point is T1 and the magnetic field strength at the highest point is T2; then let T=T2-T1; then let T1 is the magnetic field difference before the change, T2 is the magnetic field difference after the change; When the leakage flux of the power transformer changes significantly and there is T2< At T1, it can be determined that a turn-to-turn short circuit fault has occurred in the power transformer. In this determination method, it is only necessary to measure the radial magnetic field strength at both ends of the winding.

[0054] S3. Turn-to-turn fault location.

[0055] See also Figure 5 When the short-circuit fault point moves from a high position (i.e., 104 pixels) to a low position (i.e., 1 pixel), the zero-crossing point of the axial magnetic field also moves to a low position. Therefore, in the present invention, the position of the zero-crossing point of the radial magnetic field is used to locate the position of the short-circuit fault point. Figure 4 The four curves tested in the test are the conditions when the winding height is 20%~30%, 45%~55%, 70%~80% and 90%~100%, and the position corresponding to 0%~10% is drawn using its symmetry. Because there is a certain error in the measurement process itself, it is divided into certain setting values, such as Figure 5 These five curves are used to divide the transformer winding into four parts, and then locate the position of the short-circuit fault point.

[0056] In practical applications, several magnetic field sensors are arranged on the axis of the transformer to measure the radial magnetic field strength at different points, and then the required graph is made using the interpolation method to locate the transformer. Figure 1 shown.

[0057] In another embodiment of the present invention, a system for locating turn-to-turn short-circuit faults of power transformers based on leakage magnetic distribution is provided. The system can be used to implement the above-mentioned method for locating turn-to-turn short-circuit faults of power transformers based on leakage magnetic distribution. Specifically, the system for locating turn-to-turn short-circuit faults of power transformers based on leakage magnetic distribution includes a data module, a judgment module and a positioning module.

[0058] Among them, the data module obtains the radial magnetic field strength inside the power transformer; The judgment module uses a difference method to judge the occurrence of a short circuit fault based on the radial magnetic field strength; The positioning module locates the short-circuit fault point by using the position of the zero-crossing point of the radial magnetic field intensity when a short-circuit fault occurs.

[0059] In one embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the method for locating the inter-turn short-circuit fault of a power transformer based on magnetic leakage distribution, including: The radial magnetic field strength inside the power transformer is obtained; based on the radial magnetic field strength, the difference method is used to determine the occurrence of a short-circuit fault; when a short-circuit fault occurs, the position of the zero-crossing point of the radial magnetic field strength is used to locate the position of the short-circuit fault point.

[0060] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device, and can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that more specific examples (non-exhaustive list) of the computer-readable storage medium here include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0061] Computer readable storage media also include data signals propagated in baseband or as part of a carrier wave, which carry readable program codes. Such propagated data signals can take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than a readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above.

[0062] Program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).

[0063] The processor may load and execute one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the method for locating inter-turn short-circuit fault of a power transformer based on magnetic flux leakage distribution in the above embodiment; the processor may load and execute the following steps of one or more instructions in the computer-readable storage medium: The radial magnetic field strength inside the power transformer is obtained; based on the radial magnetic field strength, the difference method is used to determine the occurrence of a short-circuit fault; when a short-circuit fault occurs, the position of the zero-crossing point of the radial magnetic field strength is used to locate the position of the short-circuit fault point.

[0064] See also Figure 8 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for calculating the composition of fluid in the reservoir transformation wellbore in the embodiment is realized. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the calculation system for the composition of fluid in the reservoir transformation wellbore in the embodiment are realized. To avoid repetition, it is not described one by one here.

[0065] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 8 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0066] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, central processing units, graphics processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, data processing logic based on quantum computing, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0067] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0068] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0069] Any reference to a memory, database or other medium used in the embodiments provided in the present application may include at least one of a non-volatile and a volatile memory. Non-volatile memory may include a read-only memory (ROM), a magnetic tape, a floppy disk, a flash memory, an optical memory, a high-density embedded non-volatile memory, a resistive random access memory (ReRAM), a magnetic random access memory (MRAM), a ferroelectric random access memory (FRAM), a phase change memory (PCM), a graphene memory, etc. Volatile memory may include a random access memory (RAM) or an external cache memory, etc. As an illustration and not limitation, RAM may be in various forms, such as a static random access memory (SRAM) or a dynamic random access memory (DRAM), etc.

[0070] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0071] See also Fig. 9 The terminal device 600 is an electronic device, and the electronic device is in the form of a general computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0072] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0073] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0074] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0075] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0076] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0077] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0078] In order to verify the feasibility of the present invention, the following examples are used: Example 1 The power transformer parameters used in Example 1 are as follows: Fig.13 As shown, the three-layer windings of the power transformer are low voltage, medium voltage, and high voltage windings from the inside to the outside; the highest winding of the high voltage winding is the 104th winding, with a height of 3050mm; the lowest winding of the high voltage winding is the 1st winding, with a height of 850mm. Then we arrange several magnetic field sensors on the wall of the transformer box, and their arrangement positions are shown in the following table:

[0079] Afterwards, the arranged magnetic field sensors were used to measure the magnetic field distribution when the transformer was working normally. The results showed that the present invention can measure the leakage magnetic value more accurately.

[0080] Example 2 The 91st winding is short-circuited, and several corresponding radial magnetic field values ​​are measured. Then, the corresponding radial magnetic field distribution is obtained by interpolation method and compared with that under normal conditions. Figure 6 shown.

[0081] get T2< T1, and it occurs at 75%~100% height of the winding, which is consistent with the actual situation.

[0082] Then, the 65th winding is short-circuited, and several corresponding radial magnetic field values ​​are measured. Then, the corresponding radial magnetic field distribution is obtained by interpolation method, and compared with the normal situation. Figure 7 shown.

[0083] get T2< T1, and it occurs at 50%~75% height of the winding, which is consistent with the actual situation.

[0084] Example 2 The 65th winding is short-circuited, and several corresponding radial magnetic field values ​​are measured. Then the corresponding radial magnetic field distribution is obtained by interpolation method and compared with that under normal conditions. Figure 7 shown.

[0085] get T2< T1, and it occurs at 50%~75% height of the winding, which is consistent with the actual situation.

[0086] In summary, the present invention is a method and system for rapid monitoring and interval positioning of turn-to-turn short-circuit faults of power transformers based on changes in leakage magnetic distribution, which can realize rapid monitoring and interval positioning of turn-to-turn short-circuit faults of transformers.

[0087] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for locating inter-turn short-circuit faults of power transformers based on magnetic flux leakage distribution, characterized in that: The following steps are involved: S1. Obtain the radial magnetic field strength inside the power transformer; S2. Based on the radial magnetic field strength obtained in step S1, a difference method is used to determine the occurrence of a short circuit fault; S3. When a short circuit fault occurs, the position of the short circuit fault point is located by using the position of the zero-crossing point of the radial magnetic field intensity.

2. The method for locating turn-to-turn short-circuit fault of a power transformer based on leakage magnetic distribution according to claim 1, characterized in that: In step S1, magnetic field sensors are used to obtain the radial magnetic field strength inside the power transformer. The magnetic field sensors are arranged on the box wall of the power transformer with equal potential from top to bottom; and the magnetic field sensors at the top and bottom are high-frequency sensors.

3. The method for locating turn-to-turn short-circuit fault of power transformer based on leakage magnetic distribution according to claim 2, characterized in that: The magnetic field sensor adopts an optical fiber magnetic field sensor, which is horizontally arranged along the radial direction of the wall of the power transformer box to capture the leakage magnetic component.

4. The method for locating turn-to-turn short-circuit fault of a power transformer based on leakage magnetic distribution according to claim 3, characterized in that: In the radial direction, the optical fiber magnetic field sensor is 100-1000 mm away from the outermost side of the high-voltage winding and 1-100 mm away from the inner wall of the transformer housing.

5. The method for locating turn-to-turn short-circuit fault of power transformer based on leakage magnetic distribution according to claim 2, characterized in that: The response frequency of the high-frequency sensor is 150~250Hz.

6. The method for locating turn-to-turn short-circuit fault of power transformer based on leakage magnetic distribution according to claim 1, characterized in that: In step S2, when the changed magnetic field difference T2 is less than the magnetic field difference before the change At T1, it is determined that a turn-to-turn short circuit fault has occurred in the power transformer.

7. The method for locating inter-turn short-circuit fault of a power transformer based on leakage magnetic distribution according to claim 6 is characterized in that: The lowest magnetic field strength is T1, and the highest magnetic field strength is T2; then let T=T2-T1, get the magnetic field difference before the change T1 and the difference between the magnetic field after the change T2.

8. The method for locating turn-to-turn short-circuit fault of a power transformer based on leakage magnetic distribution according to claim 1, characterized in that: In step S3, the transformer winding is divided into four parts according to the inter-turn short-circuit magnetic field distribution curves at different points, so as to locate the position of the short-circuit fault point.

9. The method for locating turn-to-turn short-circuit fault of power transformer based on leakage magnetic distribution according to claim 8, characterized in that: The short-path magnetic field distribution curves between turns at different points are 0%~10% height, 20%~30% height, 45%~55% height, 70%~80% height and 90%~100% height of the winding.

10. A power transformer turn-to-turn short-circuit fault location system based on magnetic flux leakage distribution, characterized in that: include: Data module, obtaining radial magnetic field strength inside the power transformer; The judgment module uses a difference method to judge the occurrence of a short circuit fault based on the radial magnetic field strength; The positioning module locates the short-circuit fault point by using the position of the zero-crossing point of the radial magnetic field intensity when a short-circuit fault occurs.

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