Winding vibration analysis method and system based on vibration propagation characteristics of dry-type reactor

Abstract

The invention relates to the technical field of electric reactor vibration analysis, in particular to a winding vibration analysis method and system based on vibration propagation characteristics of a dry type electric reactor, and the method comprises the steps: analyzing the vibration characteristics of the dry type electric reactor, decomposing a magnetic field established by the dry type electric reactor, and considering the influence of axial electrodynamic force on the vibration of the electric reactor, winding axial vibration is equivalent to a multi-degree-of-freedom mass-spring-damping model, an axial winding motion equation is constructed, the influence of winding pressing force on winding loosening and the relation between the inherent frequency of the electric reactor and the pressing force are determined, the vibration response characteristics of the electric reactor under the electrified condition under different pressing forces are calculated, and the vibration response characteristics of the electric reactor under the electrified condition are calculated. And a vibration signal with obvious fault characteristics is found out and is compared with a test result when the winding works, and whether a fault occurs in the reactor or not is diagnosed. According to the method, the relationship between the pressing force and the winding resonance phenomenon is searched, and data support is provided for guaranteeing normal work of the reactor.

Description

Technical Field

[0001] The present invention relates to the technical field of reactor vibration analysis, and in particular to a winding vibration analysis method and system based on the vibration propagation characteristics of a dry-type reactor. Background Art

[0002] With the increase of power grid capacity and the improvement of power quality requirements, the use of reactors has continued to increase, and their failures have increased accordingly. This situation has directly threatened the safe operation of urban power grids and has attracted people's attention. As a key equipment for power transmission and transformation of power systems, the reliable operation of reactors is of great significance to the safe, economical and stable operation of power systems.

[0003] Therefore, the reactor is the most important equipment in the power system, and its safe and reliable operation is related to the stability of the system operation. Various anti-fault studies must be carried out on it.

[0004] There are many types of failures in reactors, such as failures caused by lax quality control during the bolt assembly process, structural design defects, loose components caused by long-term vibration, breakage problems, poor welding, insulation defects, component quality problems, poor core grounding, and unqualified on-site installation processing technology.

[0005] There are many reasons for mechanical vibration defects. Among the known reasons, lax quality control of bolt assembly and structural design defects can lead to internal mechanical looseness defects during the long-term operation of the reactor due to the existence of vibration, thus causing mechanical failure. Therefore, studying the vibration issues of the reactor and ensuring the safe and reliable operation of the reactor are the key to maintaining the stability of the power system.

[0006] Vibration-based diagnostic methods are relatively mature in the application of rotating machinery (generators, large pumps, etc.), and can be used for reference and learning, but they have been applied to reactors relatively late. Research on them has been very hot in recent years, and there have been a number of literature reports on related research.

[0007] Based on the above literature reports, although there are many diagnostic methods for reactors, and they have made important contributions to reactor fault diagnosis, the overall effect is not very ideal and cannot meet the requirements of modern power systems, especially the requirements of smart grid development. This is mainly due to the complex internal structure of the reactor and the strong interference at the reactor operation site, which makes monitoring and diagnosis difficult. Therefore, few people in the prior art have studied the relationship between reactor winding deformation, winding looseness and other faults caused by reactor vibration, and thus the prior art cannot analyze the vibration changes caused by changes in the mechanical properties of the reactor winding.

[0008] For example, the invention patent with publication number CN117912198A discloses an early warning prediction system for reactors, which monitors the phase difference between zero-sequence current and zero-sequence voltage through an early warning discrimination module to perform adaptive compensation and analysis under different fault conditions. The system can monitor the status and data of the reactor in real time and can provide reliable early warnings and future trend predictions to determine future faults, and can operate stably and for a long time in the environment of high electromagnetic fields and high currents inside the reactor, but it still has not established the relationship between the reactor structure and the characteristic quantity of the vibration signal, and the accuracy needs to be improved.

[0009] For example, the invention patent with publication number CN117875082A discloses a method and system for simulating inter-turn short-circuit faults of dry-type air-core reactors, which establishes a geometric model of the dry-type air-core reactor, but the factors considered are only the electromagnetic field, temperature field and fluid field, and the influence of the reactor structure itself on the vibration is not considered. Therefore, the prediction result cannot be guaranteed to be accurate.

[0010] For example, the invention patent with publication number CN116593934 A discloses a method and device for monitoring short-circuit faults between turns of a dry-type hollow current-limiting reactor, which takes into account short-circuit faults between turns of the reactor, and does not involve faults caused by vibration changes of the reactor. Therefore, it is different from the technical problem solved by the present application, and the technical solution is also completely different.

[0011] For example, the invention patent with publication number CN116306212A discloses a method, device, equipment and storage medium for predicting reactor faults, which forms sample pairs with the acquired reactor operating status values, inputs them into a pre-trained LSTM-based twin network to predict reactor faults and obtain prediction results. Due to the complex structure of the reactor, it is obviously impossible to obtain accurate prediction results by only using a neural network model. Summary of the invention

[0012] Purpose of the invention: In order to overcome the deficiencies of the prior art, the present invention provides a winding vibration analysis method based on the vibration propagation characteristics of a dry-type inductor. The method solves the problem in the prior art that the relationship between winding looseness and the axial electromotive force of the reactor winding is not understood, and further the mechanical properties of the reactor winding cannot be diagnosed and evaluated through the relationship between the axial electromotive force and the clamping force. The present invention also provides a winding vibration analysis system based on the vibration propagation characteristics of a dry-type inductor.

[0013] Technical solution: According to a first aspect of the present invention, a winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor is provided, the method comprising:

[0014] Analyze the vibration characteristics of the dry-type reactor, and decompose the magnetic field established by the dry-type reactor, wherein the decomposition direction is along the radial direction and the axial direction of the winding. The radial magnetic field and the current interact to generate an axial electromotive force, and the axial magnetic field and the current interact to generate a radial electromotive force. Under the action of the electromotive force, the winding vibrates;

[0015] Considering the influence of axial electromotive force on the vibration of the reactor, the axial vibration of the winding is equivalent to a multi-degree-of-freedom mass-spring-damper model, and the axial winding motion equation is constructed based on the multi-degree-of-freedom mass-spring-damper model, wherein the winding is a coil-wound coil structure constituting a mass unit, the insulating spacers between the coils constitute a spring unit, and other external factors of the reactor constitute a damping unit;

[0016] Then, the influence of winding clamping force on winding looseness and the relationship between the natural frequency of the reactor and the clamping force are determined, so as to calculate the vibration response characteristics of the reactor under different clamping forces when energized, find out the vibration signal with obvious fault characteristics, and compare it with the test results when the winding is working, diagnose whether there is a fault inside the reactor, and further determine the fault location.

[0017] Further, including:

[0018] The vibration characteristics of the dry-type reactor include:

[0019] The vibration of the dry-type reactor is generated by the cooling system and the body. The vibration of the cooling system is caused by the rotation of the heat sink and the fan. The vibration of the body includes the vibration of the winding and the iron core. The vibration of the winding is generated by the contact between the cardboard, the pad and the iron core, and the generated vibration signal is transmitted to the surface of the reactor. The winding is divided into multiple layers of coils, each layer of coils is wound by multiple turns of coils, and the overall structure is cylindrical.

[0020] Further, including:

[0021] The multi-degree-of-freedom mass-spring-damper model includes constructing an axial winding motion equation, including:

[0022]

[0023] Among them, z1, z2, ... z n-1 、z n are the axial displacements of each coil, m1, m2, ...m n-1 、m n are the mass of each coil, F a1 、F a2 ,……F a(n-1) 、F an are the axial electromotive forces on each coil, c1, c2, ... c n-1 、cn are the damping coefficients of each coil of the reactor, k t , k1……k n-1 , k b are the elastic coefficients between the insulating pads of the wire cakes, and g is the acceleration of gravity;

[0024] It is expressed in matrix form as:

[0025]

[0026] in,

[0027]

[0028]

[0029] According to the actual operation status of the reactor, the parameters in formula (2) are reasonably simplified and equivalent, assuming that the axial displacement of each coil is equal, that is, z1 = z2 = ... = z n-1 =z n =z; the mass of each coil is equal, that is, m1 = m 2＝ ……=m n-1 =m n =m; the damping coefficient of each coil of the reactor is equal, that is, c1 = c 2＝ ……=c n-1 =c n = c; the elastic coefficients between the insulating pads of the wire cake are equal, k t =k1=……=k n-1 =k b = k, so after addition, it is expressed as:

[0030]

[0031] Among them, M = nm is the mass of the coil, C = nc is the damping coefficient of the reactor coil, K = k t +k b =2k is the elastic coefficient of the insulating pad, z are the acceleration, velocity and displacement of the axial motion of the coil, Axial electric force.

[0032] Further, including:

[0033] The determining of the influence of the winding pressing force on the winding loosening includes:

[0034] First, according to the law of electromagnetic induction and the left-hand rule, assuming that the current I = I0cos(ω0t), the axial electromotive force on the winding is:

[0035]

[0036] Wherein, k is the calculation parameter; I0 is the current amplitude, ω0 is the angular frequency;

[0037] Therefore, the electromotive force on the axial direction of the reactor winding is the superposition of an AC component twice the industrial frequency and a DC component. Since the DC component electromotive force is equivalent to a constant force, this electromotive force is negligible relative to the axial clamping force. Therefore, the reactor is acted on by the AC component electromotive force in the axial direction, and the frequency is 100Hz. At the same time, due to the complex structure of the winding and the influence of the nonlinear factors of the magnetization curve, the vibration frequency of the winding is 100Hz and its multiples.

[0038] Combining formula (3) and (4) it can be expressed as:

[0039]

[0040] Among them, the size of the elastic coefficient K of the insulating spacer is related to the degree of compression of the reactor winding. During the stable operation of the reactor, the compression force on the winding is constant, that is, when the reactor is in a stable state, the elastic coefficient K can be equivalent to a constant. Therefore, under the condition of a certain winding mass, the natural frequency of the winding can be changed by changing the elastic coefficient of the insulating spacer, that is, changing the degree of compression of the winding, so as to achieve the purpose of making the natural frequency of the winding away from the electromotive force frequency and its multiples, thereby avoiding resonance.

[0041] Further, including:

[0042] The method of changing the compression degree of the winding to change the natural frequency of the winding so as to make the natural frequency of the winding away from the electromotive force frequency and its multiples, thereby avoiding resonance, includes:

[0043] A non-homogeneous linear differential equation with constant coefficients, whose solution is the general solution of the homogeneous equation plus the special solution of the non-homogeneous equation.

[0044] Therefore, the homogeneous equation corresponding to formula (5) is:

[0045]

[0046] The general solution is:

[0047]

[0048] Where: p, is a parameter related to the initial state of the winding, f=λ / (2π) is the natural frequency of the winding and complies with 4MK>>C 2 ,Right now

[0049] The non-homogeneous equation is decomposed into two:

[0050]

[0051] The particular solutions are obtained respectively as follows:

[0052]

[0053] Where:

[0054]

[0055] Therefore, the general solution of equation (9) is obtained:

[0056]

[0057] Taking the second derivative of formula (10) respectively, the axial vibration acceleration of the winding can be obtained:

[0058]

[0059] According to the above, the natural frequency of the winding f = λ / (2π), and the winding also vibrates at a frequency of 100 Hz and its multiples, as well as the expression of the vibration acceleration.

[0060] Furthermore, it includes:

[0061] Calculating the vibration response characteristics of the reactor under different clamping forces when energized, and finding out the vibration signals with obvious fault characteristics, including:

[0062] Since the clamping force of the winding increases, the elastic coefficient K increases, and the natural frequency f of the winding increases; when the clamping force of the winding decreases, the elastic coefficient K decreases, and the natural frequency f of the winding decreases, but the relationship between the natural frequency f of the winding and the electrodynamic vibration frequency f0 = 2ω0 / (2π) = 100 Hz is unknown. Therefore, the following conclusions are drawn:

[0063] (1) If f < f0, the vibration amplitude of the winding increases with the increase of the clamping force, and resonance will not occur, but it is necessary to prevent the natural frequency of the winding from reaching the critical frequency of the electrodynamic fundamental frequency of 100 Hz during the process of increasing the clamping force;

[0064] (2) If f = f0, the natural frequency of the winding is the same as the electrodynamic frequency, resulting in resonance and generating strong vibrations. If the reactor operates for a long time under this condition, the winding will become loose, leading to internal mechanical failures;

[0065] (3) If f > f0, the vibration amplitude of the winding shows a periodic characteristic of decreasing first and then increasing with the increase of the clamping force; it decreases first because the natural frequency of the winding gradually moves away from 100 Hz and its multiples; it increases later because the natural frequency of the reactor winding gradually approaches the multiple of 100 Hz;

[0066] Therefore, if the clamping force is too small, the winding will not resonate, but it will also cause insufficient clamping force and cause looseness; if the clamping force is too large, it will easily approach the multiple of 100Hz while being far away from the 100Hz frequency, causing resonance. Therefore, it is necessary to reasonably calculate and select the appropriate clamping force to ensure the normal operation of the reactor winding and prevent looseness.

[0067] Further, including:

[0068] The electric force F on the coil axial direction an It is obtained by superposition of the axial electromotive force received by each layer of coils, which is generated by the interaction between the radial component of magnetic induction intensity and the current. The radial component is expressed as:

[0069]

[0070] in, W is the total number of coils in the current coil, t∈[1,W], n j is the coefficient of magnetic induction intensity formed by the j-th layer coil, e 2 =r i 2 +z i 2 , k 2 =4r i 2 r j / L 2 , 0 is the vacuum permeability, r i 、r j is the winding radius of the i-th and j-th layers of coils, H j is the winding height of the j-th layer coil, and i≠j, z is the Z-axis value corresponding to the j-th layer coil, and the bottom center of the coil is used as the coordinate point, and the X, Y, and Z axes are set respectively. The positive direction of the Z axis is the direction from the center of the bottom coil to the center of the top coil along the coil. Therefore, according to Ampere's law and superposition theorem, the radial component B of the magnetic induction intensity is determined. r The distribution of (t).

[0071] On the other hand, a winding vibration analysis system based on the vibration propagation characteristics of a dry-type reactor comprises:

[0072] A vibration characteristic analysis module is used to analyze the vibration characteristics of the dry-type reactor and decompose the magnetic field established by the dry-type reactor. The decomposition direction is along the radial and axial directions of the winding. The radial magnetic field and the current interact to generate an axial electromotive force, and the axial magnetic field and the current interact to generate a radial electromotive force. Under the action of the electromotive force, the winding vibrates;

[0073] A model building module is used to consider the influence of axial electromotive force on the vibration of the reactor, to equate the axial vibration of the winding to a multi-degree-of-freedom mass-spring-damper model, and to build an axial winding motion equation based on the multi-degree-of-freedom mass-spring-damper model, wherein the winding is a coil-wound coil structure constituting a mass unit, the insulating pads between the coils constituting a spring unit, and other external factors of the reactor constituting a damping unit;

[0074] The fault determination module is used to determine the impact of the winding clamping force on the winding looseness and the relationship between the natural frequency of the reactor and the clamping force, so as to calculate the vibration response characteristics of the reactor under different clamping forces when energized, find out the vibration signal with obvious fault characteristics, and compare it with the test results when the winding is working, diagnose whether there is a fault inside the reactor, and further determine the fault location.

[0075] Further, including:

[0076] In the vibration characteristic analysis module, the vibration characteristics of the dry-type reactor include:

[0077] The vibration of the dry-type reactor is generated by the cooling system and the body. The vibration of the cooling system is caused by the rotation of the heat sink and the fan. The vibration of the body includes the vibration of the winding and the iron core. The vibration of the winding is generated by the contact between the cardboard, the pad and the iron core, and the generated vibration signal is transmitted to the surface of the reactor. The winding is divided into multiple layers of coils, each layer of coils is wound by multiple turns of coils, and the overall structure is cylindrical.

[0078] Finally, the present application also provides a computer-readable storage medium, on which is stored a winding vibration analysis program based on the vibration propagation characteristics of a dry-type inductor. When the winding vibration analysis program based on the vibration propagation characteristics of a dry-type inductor is executed by a processor, the steps of the winding vibration analysis method based on the vibration propagation characteristics of a dry-type inductor as described above are implemented.

[0079] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0080] This application seeks the relationship between the clamping force and the resonance phenomenon of the windings based on the characteristics of the vibration of the top of the reactor caused by the electromagnetic force of the winding axial direction and the electromagnetic attraction between the core disks through the solid transmission paths such as the yoke on the core and various clamps, and combines the experimental method to more effectively study the vibration characteristics of the reactor, that is, the compression and deformation of the windings have a great relationship with the vibration of the reactor. Therefore, the compression condition of the reactor core and the compression condition of the windings can be reflected in the vibration of the reactor to a large extent. If the condition of the reactor core and the compression condition of the windings are good, the vibration of the reactor will be relatively stable, which also provides a basis for eliminating the fault of increased vibration of the reactor.

[0081] The present application firstly equates the axial vibration of the winding of the reactor to a multi-degree-of-freedom mass-spring-damper model, and sets the axial winding motion equation based on the model, and solves the axial winding motion equation to obtain the corresponding axial vibration acceleration of the winding, the natural frequency of the winding and the clamping force, so as to reasonably select the appropriate clamping force according to the calculation formula to ensure the normal operation of the reactor winding without causing looseness, thereby ensuring the stable operation of the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 This is a flow chart of a winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to Embodiment 1 of the present invention;

[0083] Figure 2 This is a schematic diagram of an equivalent calculation model for a reactor magnetic field according to Embodiment 1 of the present invention;

[0084] Figure 3 This is a schematic diagram of the distribution of magnetic field components of the reactor according to Embodiment 1 of the present invention;

[0085] Figure 4 This is a schematic diagram of the axial equivalent system model of the reactor winding according to Embodiment 1 of the present invention;

[0086] Figure 5 This is a schematic diagram of a reactor vibration test platform according to Embodiment 1 of the present invention;

[0087] Figure 6 This is a schematic diagram of the internal distribution of sensors in a reactor in a reactor vibration experiment according to Embodiment 1 of the present invention;

[0088] Figure 7 This is a schematic diagram of the external distribution of sensors on a reactor in a reactor vibration experiment according to Embodiment 1 of the present invention;

[0089] Figure 8 This is a schematic diagram of the structure of the reactor vibration monitoring and diagnosis system based on LabVIEW according to Example 1 of the present invention;

[0090] Fig. 9 It is a software program flow chart corresponding to the reactor monitoring and diagnosis system described in Example 1 of the present invention. DETAILED DESCRIPTION

[0091] 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 only 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.

[0092] Example 1

[0093] In a first aspect of the present invention, a winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor is provided. Figure 1 As shown, the method includes:

[0094] Step S1 analyzes the vibration characteristics of the dry-type inductor and decomposes the magnetic field established by the dry-type inductor, wherein the decomposition direction is along the radial and axial directions of the winding. The radial magnetic field and the current interact to generate an axial electromotive force, and the axial magnetic field and the current interact to generate a radial electromotive force. Under the action of the electromotive force, the winding vibrates.

[0095] In this embodiment, the vibration of the reactor is mainly generated by the cooling system and the body, and the vibration of the cooling system is caused by the rotation of the heat sink and the fan.

[0096] The vibrations generated by the reactor cooling system include the air flow around the heat sink and the vibrations caused by aerodynamic reasons when the fan rotates.

[0097] Among them, aerodynamic vibration is the main part, which is manifested as periodic exhaust vibration caused by pressure pulsation caused by the periodic rotation of the fan impeller to exhaust gas outward, and eddy current vibration caused by the splitting of gas vortex on the fan blade surface. Its vibration mode is relatively simple, and the frequency generated shows medium and low frequency characteristics, that is, the vibration frequency is below 100Hz, which is quite different from the vibration characteristics of the reactor body with 100Hz as the multiple frequency, and it is also easier to distinguish.

[0098] The vibration sources of the reactor body are the winding and the iron core, and the vibration signals of both are transmitted to the surface through the liquid medium and the solid medium. The winding contacts the pad and the iron core through the cardboard, and the vibrations generated by the two interact and influence each other through the solid medium in the middle, and their vibration signals are transmitted to the surface of the reactor. Therefore, the vibration of the reactor body mainly uses liquid and solid as the transmission path. In the process of vibration propagation to the surface of the reactor, the vibration signals generated by the winding and the iron core are superimposed on each other and influence each other. Through different transmission paths, the vibration signals will have different degrees of attenuation and different characteristics.

[0099] The main reasons for the vibration of the reactor are the electromagnetic force on the winding, magnetostriction of the iron core, and the electromagnetic force on the iron core, which are transmitted to the surface through the reactor support components and other paths. The axial electromagnetic force of the winding and the electromagnetic attraction between the core cakes cause the top of the reactor to vibrate through solid transmission paths such as the yoke on the core and various clamps. In practice, the vibration of the reactor will continue to attenuate during the propagation process, and due to the complex structure of the reactor, it is easy to cause the refraction and reflection of the vibration wave, which brings difficulties to the analysis of the vibration propagation law of the reactor. Therefore, based on theoretical analysis, combined with experimental methods, the vibration characteristics of the reactor can be more effectively studied.

[0100] Similar to the structure of the reactor winding, the reactor winding is wound with copper wire and arranged in a self-adhesive transposition form, presenting a tangled pancake structure and a cylindrical shape. AC voltage is passed through both ends of the reactor winding, generating current and establishing a magnetic field in space. In the space where the leakage magnetic field is distributed, the magnetic lines of force can be decomposed into radial and axial lines along the winding. The radial magnetic field and current interact to generate axial electromotive force, and the axial magnetic field and current interact to generate radial electromotive force. Under the action of the electromotive force, the winding vibrates. In order to effectively analyze the vibration of the winding, it can be decomposed into axial and radial lines.

[0101] The reactor body is composed of multiple windings, each winding is divided into multiple layers of coils, and each layer of coils is wound by multiple turns of coils. The overall structure is cylindrical.

[0102] Step S2 considers the influence of axial electromotive force on the vibration of the reactor, equates the axial vibration of the winding to a multi-degree-of-freedom mass-spring-damper model, and constructs the axial winding motion equation based on the multi-degree-of-freedom mass-spring-damper model, wherein the winding is a coil-wound coil structure constituting a mass unit, the insulating spacers between the coils constitute a spring unit, and other external factors of the reactor constitute a damping unit.

[0103] Assume the reactor has N windings, each winding is connected in parallel with M i Layer conductors, total Therefore, the reactor can be equivalent to a coil with W layers wound in parallel in terms of physical structure, and can be equivalent to a branch with W resistors and inductors connected in parallel in terms of circuit.

[0104] The equivalent calculation model of the reactor magnetic field is as follows: Figure 2 shown. Figure 2 In, r i 、r j H is the winding radius of each layer of coil, i , H j is the winding height of each layer of coil, is the angle between any point P in space and the Z axis, I j dl is the current element calculated for each layer of coil.

[0105] The calculation method of the magnetic field generated by the circular current in space is more general. The reactor has a clockwise layer current I j The axial component B of the superimposed magnetic induction intensity generated at any point P in space a (i) and radial component B r (i) is:

[0106]

[0107] Where: n j As parameters, e 2 =ri 2 +z i 2 , k 2 =4r i 2 r j / L 2 , 0 is the magnetic permeability of vacuum.

[0108] According to Ampere's law and superposition theorem, determine the axial component B of the magnetic induction intensity. a (i) and radial component B r (i) Distribution.

[0109] (1) When r i >r N When the magnetic field direction changes, the radial component remains unchanged, while the axial component changes. N is the distance at which the direction of the axial magnetic field changes;

[0110] (2) When H i >H N When the magnetic field direction changes, the axial component follows the change law of (1), and the radial component also changes. N Specific height for specific reactor windings.

[0111] According to the above, the distribution diagram of magnetic field components is as follows: Figure 3 As shown, it is assumed that the reactor is passed through by a clockwise current, with the vertical direction upward being the positive direction and the horizontal direction pointing to the inside of the reactor being the positive direction.

[0112] In this embodiment, the winding coil structure is composed of a mass unit, the insulating pads between the coils are composed of a spring unit, and other external factors of the reactor are composed of a damping unit. Therefore, the axial vibration of the winding can be equivalent to a multi-degree-of-freedom mass-spring-damper model, and its axial equivalent system model is as follows: Figure 4 shown.

[0113] according to Figure 4 And Newton's laws of motion, the axial winding motion equation is:

[0114]

[0115] Where: z1, z2, ... z n-1 、z n are the axial displacement of each coil, m1, m2, ... m n-1 、m n are the mass of each coil, F a1 、F a2 ……F a(n-1) 、Fan are the axial electromotive forces on each coil, c1, c2, ... n-1 、c n are the damping coefficients of each coil of the reactor, k t , k1……k n-1 , k b are the elastic coefficients between the insulating spacers of the wire discs.

[0116] Expressed in matrix form, it is:

[0117]

[0118] Where:

[0119]

[0120]

[0121] According to the actual operation status of the reactor, the parameters in equation (3) are reasonably simplified and equivalent. Assume that the axial displacement of each coil is equal, that is, z1 = z2 = ... = z n-1 =z n =z; the mass of each coil is equal, that is, m1 = m 2＝ ……=m n-1 =m n =m; the damping coefficient of each coil of the reactor is equal, that is, c1 = c 2＝ ……=c n-1 =c n = c; the elastic coefficients between the insulating pads of the wire cake are equal, k t =k1=……=k n-1 =k b =k.

[0122] Adding them together gives:

[0123]

[0124] Where: M = nm is the mass of the coil, C = nc is the damping coefficient of the reactor coil, K = k t +k b =2k is the elastic coefficient of the insulating pad, z are the acceleration, velocity and displacement of the axial motion of the coil, Axial electric force.

[0125] According to the law of electromagnetic induction and the left-hand rule, assuming that the current I = I0cos(ω0t), the axial electromotive force on the winding is:

[0126]

[0127] Where: k is the calculation parameter; I0 is the current amplitude.

[0128] It can be seen that the electromotive force on the reactor winding in the axial direction is a superposition of an AC component twice the power frequency and a DC component. The DC component electromotive force is equivalent to a constant force, which can be ignored relative to the axial clamping force. Therefore, the reactor is mainly affected by the AC component electromotive force in the axial direction, with a frequency of 100Hz. At the same time, due to the complex structure of the winding and the nonlinearity of the magnetization curve, the winding vibration frequency is 100Hz and its multiples.

[0129]

[0130] The elastic coefficient K of the insulating spacer is often a variable parameter, and its size is related to the degree of compression of the reactor winding. During the stable operation of the reactor, the compression force on the winding is constant, that is, when the reactor is in a stable state, the elastic coefficient K can be equivalent to a constant.

[0131] Step S3 further determines the influence of the winding clamping force on the winding looseness and the relationship between the natural frequency of the reactor and the clamping force, so as to calculate the vibration response characteristics of the reactor under different clamping forces when energized, find out the vibration signal with obvious fault characteristics, and compare it with the test results when the winding is working, diagnose whether there is a fault inside the reactor, and further determine the fault location.

[0132] According to formula (6), it can be seen that it is a non-homogeneous linear differential equation with constant coefficients, and its solution is the general solution of the homogeneous equation plus the special solution of the non-homogeneous equation.

[0133] Homogeneous equations:

[0134]

[0135] The general solution is:

[0136]

[0137] Where: p, is a parameter related to the initial state of the winding, f=λ / (2π) is the natural frequency of the winding, generally 4MK>>C 2 ,Right now

[0138] It can be seen that the natural frequency of the winding can be changed by changing the mass of the winding and the elastic coefficient of the insulating spacer. In the actual production process, under the condition of a certain mass of the winding, the natural frequency of the winding is often changed by changing the elastic coefficient of the insulating spacer, that is, changing the degree of compression of the winding, so as to achieve the purpose of keeping the natural frequency of the winding away from the electromotive force frequency and its multiples, thereby avoiding resonance.

[0139] The inhomogeneous equation is decomposed into two:

[0140]

[0141] The particular solutions of them are obtained respectively as:

[0142]

[0143] Where:

[0144] Therefore, the general solution of equation (11) is obtained:

[0145]

[0146] Taking the second derivative of equation (12) respectively, the axial vibration acceleration of the winding can be obtained:

[0147]

[0148] According to the vibration acceleration expression and the above, the natural frequency of the winding f = λ / (2π), and the winding also vibrates at a frequency of 100 Hz and its multiple frequencies.

[0149] At the same time, as the winding pressing force increases, the elastic coefficient K increases, and the natural frequency f of the winding increases;

[0150] as the winding pressing force decreases, the elastic coefficient K decreases, and the natural frequency f of the winding decreases.

[0151] However, the relationship between the natural frequency f of the winding and the electrodynamic vibration frequency f0 = 2ω0 / (2π) = 100 Hz is unknown. Through analysis, the following conclusions can be drawn:

[0152] (1) If That is, f < f0, the vibration amplitude of the winding increases with the increase of the pressing force, and resonance will not occur. However, it is necessary to prevent the natural frequency of the winding from reaching the critical frequency of the electrodynamic fundamental frequency of 100 Hz during the increase of the pressing force.

[0153] (2) If That is, f = f0, the natural frequency of the winding is the same as the electrodynamic frequency, resulting in resonance and strong vibration. If the reactor operates for a long time in this case, the winding will become loose and cause internal mechanical failures.

[0154] (3) If That is, f > f0, the vibration amplitude of the winding shows a periodic characteristic of first decreasing and then increasing with the increase of the pressing force. It first decreases because the natural frequency of the winding gradually moves away from 100 Hz and its multiple frequencies; it then increases because the natural frequency of the reactor winding gradually approaches the multiple frequency of 100 Hz.

[0155] From the above analysis, we can know that if the clamping force is too small, the winding will not resonate, but it will also cause the lack of clamping force and looseness; if the clamping force is too large, it will be close to the multiple of 100Hz while being far away from the 100Hz frequency, causing resonance. Therefore, it is necessary to reasonably calculate and select the appropriate clamping force to ensure the normal operation of the reactor winding and prevent looseness.

[0156] Therefore, based on the above method steps, it can be known that if the reactor winding is loose, the vibration of the winding will increase; when a momentary short circuit occurs and causes the winding insulation to break down, the vibration of the winding will also increase.

[0157] Similarly, after one of the high or low voltage windings is deformed, displaced or collapsed, the winding is not tightened enough, causing the height difference between the high and low voltage windings to gradually expand, resulting in increased unbalance in the winding ampere-turns, increased axial force caused by leakage magnetic flux, and thus increased vibration of the winding.

[0158] The compression and deformation of the windings have a great relationship with the vibration of the reactor. Therefore, the compression of the reactor core and the windings can be reflected in the vibration of the reactor to a large extent. If the reactor core and the winding compression are in good condition, the reactor vibration will be relatively stable. This also provides a basis for eliminating the fault of increased reactor vibration.

[0159] When the reactor is working stably, it can be considered that the vibration of the reactor body is caused by the vibration of the iron core, and the change of vibration is also caused by the iron core failure. When a short circuit occurs in the reactor, a large impact current flows through the winding coil, and the vibration signal of the winding is much larger than the core vibration. Therefore, under the short circuit condition, the vibration of the reactor body is mainly caused by the vibration of the winding. In this way, the vibration signal of the reactor body during / after the short circuit accident can be used to monitor whether the winding coil is deformed or loose.

[0160] Based on the research on the axial electrodynamic force of the winding, S4 further established the vibration model of the reactor winding, the vibration model of the reactor core, and the vibration model of the reactor box, and then carried out vibration experiments on the reactor equivalent model, so as to monitor the vibration of the reactor and finally make an accurate judgment on the reactor status, realizing various status alarm functions such as reactor abnormality and failure.

[0161] Example 2

[0162] On the other hand, the present invention also provides a winding vibration analysis system based on the vibration propagation characteristics of a dry-type reactor, the system comprising:

[0163] A vibration characteristic analysis module is used to analyze the vibration characteristics of the dry-type reactor and decompose the magnetic field established by the dry-type reactor. The decomposition direction is along the radial and axial directions of the winding. The radial magnetic field and the current interact to generate an axial electromotive force, and the axial magnetic field and the current interact to generate a radial electromotive force. Under the action of the electromotive force, the winding vibrates;

[0164] A model building module is used to consider the influence of axial electromotive force on the vibration of the reactor, to equate the axial vibration of the winding to a multi-degree-of-freedom mass-spring-damper model, and to build an axial winding motion equation based on the multi-degree-of-freedom mass-spring-damper model, wherein the winding is a coil-wound coil structure constituting a mass unit, the insulating pads between the coils constituting a spring unit, and other external factors of the reactor constituting a damping unit;

[0165] The fault determination module is used to determine the impact of the winding clamping force on the winding looseness and the relationship between the natural frequency of the reactor and the clamping force, so as to calculate the vibration response characteristics of the reactor under different clamping forces when energized, find out the vibration signal with obvious fault characteristics, and compare it with the test results when the winding is working, diagnose whether there is a fault inside the reactor, and further determine the fault location.

[0166] Further, including:

[0167] In the vibration characteristic analysis module, the vibration characteristics of the dry-type reactor include:

[0168] The vibration of the dry-type reactor is generated by the cooling system and the body. The vibration of the cooling system is caused by the rotation of the heat sink and the fan. The vibration of the body includes the vibration of the winding and the iron core. The vibration of the winding is generated by the contact between the cardboard, the pad and the iron core, and the generated vibration signal is transmitted to the surface of the reactor. The winding is divided into multiple layers of coils, each layer of coils is wound by multiple turns of coils, and the overall structure is cylindrical.

[0169] Other technical features of the winding vibration analysis system based on the vibration propagation characteristics of the dry-type inductor described in this embodiment are similar to the corresponding winding vibration analysis method based on the vibration propagation characteristics of the dry-type inductor, and are not repeated here.

[0170] Finally, the present application also provides a computer-readable storage medium, on which is stored a winding vibration analysis program based on the vibration propagation characteristics of a dry-type inductor. When the winding vibration analysis program based on the vibration propagation characteristics of a dry-type inductor is executed by a processor, the steps of the winding vibration analysis method based on the vibration propagation characteristics of a dry-type inductor as described above are implemented.

[0171] In order to implement the winding vibration analysis method based on the vibration propagation characteristics of the dry-type reactor, this embodiment conducts a simulation experiment, including:

[0172] (1) Draw the loose model of reactor winding

[0173] The reactor model is drawn using CAD (Computer Aided Design) 3D drawing software Pro / Engineer. The structural rods, pads, cores, coils and other parts are drawn first, and then the parts are assembled into a reactor model through the software assembly function.

[0174] (2) Import finite element software

[0175] The 3D drawing software Pro / Engineer and the finite element software ANSYS have an import interface that can import the drawn reactor model into the finite element software for related analysis and research.

[0176] (3) Set material parameters

[0177] The setting of material parameters of each part in the model is a critical part for finite element analysis, and the nonlinear characteristics of the insulating pad will cause its elastic modulus to change with the change of the clamping force. Due to the material of the pad and its loose structure, when the pressure load applied to the pad changes, the elastic coefficient of the insulating pad is related to the degree of clamping after assembly. Therefore, it is necessary to calculate the elastic modulus of the insulating pad under different clamping forces to simulate the influence of winding looseness on the reactor.

[0178] (4) Modal analysis

[0179] Modal analysis is used to determine the vibration characteristics of a structure. Its essence is to solve the motion equations with a limited number of degrees of freedom under undamped and external load conditions, and obtain the eigenvalues ​​and eigenvectors of the equations, that is, the natural frequencies and modal vibration shapes of each mode. This is to determine the different effects of each order of frequency and vibration shape on the structure, and through reasonable design, the natural frequency of the reactor is kept away from the excitation force frequency to avoid resonance, and to predict the actual vibration response of the reactor winding structure under external excitation within its natural frequency range. Since the vibration characteristics determine the response of the structure to various dynamic loads, any form of dynamic analysis must be based on modal analysis.

[0180] (5) Harmonic response analysis

[0181] Harmonic response analysis is to determine the steady-state response of the structure under the action of a sinusoidal load of known frequency and amplitude, calculate the vibration of the structure at different frequencies, and obtain the vibration amplitude curve. When the reactor is working, under the excitation of electromagnetic force, the vibration of the coil can be regarded as simple harmonic motion. Harmonic response analysis can determine the continuous dynamic performance of the winding to avoid resonance caused by forced vibration. The modal superposition method is used in the analysis, which multiplies the vibration mode obtained by the modal analysis by a factor and calculates the response of the structure by summing. The modal superposition method is faster and less expensive than the complete method, includes the prestressing effect, and can make the solution cluster according to the natural frequency of the structure, which can produce a smoother and more accurate response curve.

[0182] (6) Experimental verification and loosening diagnosis research

[0183] The correctness of the finite element model can be verified through the above simulation calculations and experimental research. Based on this, the vibration response characteristics of the reactor under different clamping forces under energized conditions can be calculated to find vibration signals with obvious fault characteristics, and compared with the test results when the winding is working, it is possible to diagnose whether there is a fault inside the reactor and further determine the fault location.

[0184] First of all, the reactor vibration test platform includes:

[0185] The reactor vibration experiment platform is composed of hardware and software. The hardware includes piezoelectric acceleration vibration sensor, signal acquisition instrument, and laptop computer. The software includes DHDAS software platform. Figure 5 shown.

[0186] The hardware part:

[0187] There are two types of current sensors. One type is a clamp-type current sensor, which is easy to use but has relatively low accuracy and is not suitable for measuring fast transient signals. This type of sensor is used in general experiments of this application.

[0188] The other type is the Hall-type current sensor of LEM Company, which has good dynamic performance and high accuracy. This application uses this sensor in the experiment of measuring transient current signals and requiring high accuracy.

[0189] The selection of voltage sensor is similar to that of current sensor.

[0190] Vibration sensor: This application simultaneously measures the vibration of the reactor in different states. Based on the previous research on vibration signals, the characteristics of vibration signals are fully considered, and finally the piezoelectric acceleration vibration sensor model IA212E is selected. The specific parameters are shown in Table 1.

[0191] Table 1IA212E piezoelectric acceleration vibration sensor parameters

[0192]

[0193] The IA212E piezoelectric acceleration vibration sensor has a sensitive chip inside, which converts and outputs a charge signal proportional to the acceleration amplitude, which is displayed as a voltage amplitude on the interface; the sensor itself has a high resonant frequency, which can avoid the generation of resonant components and ensure the high quality of the original signal without signal distortion; it is light in weight, ensuring that the vibration signal at the installation location will not be changed; it has high sensitivity, and the output signal has a high signal-to-noise ratio with obvious details, which is conducive to signal analysis and subsequent fault diagnosis; the output signal line uses a shielded coaxial cable to avoid interference from the strong magnetic environment outside.

[0194] The IA212E piezoelectric acceleration vibration sensor has a magnetic disk at the bottom, which can be firmly adsorbed on the surface of the reactor from the outside. Considering the insulation problem, the sensor is fixed to the core and windings internally by gluing and bundling. In the vibration measurement environment, no movement or vibration occurs, ensuring that the collected data is true and reliable.

[0195] The vibration signal acquisition and analysis instrument is the core hardware part of the reactor vibration experiment, taking into account multiple functions such as signal acquisition, recording, filtering, analysis and conditioning. At the same time, in order to reduce the number of points, the channels should be as many as possible. After considering the above issues, the DH5992D multi-channel dynamic signal acquisition and analysis instrument was finally selected. The specific parameters are shown in Table 2.

[0196] Table 2 DH5992D multi-channel dynamic signal acquisition analyzer parameters

[0197]

[0198] DH5992D multi-channel dynamic signal acquisition analyzer has 16 channels to collect vibration signals simultaneously, which meets the needs of multiple measurement points to the greatest extent, reduces the trouble of point layout and the error caused by manual movement of sensors; the sampling frequency is as high as 256kHz, collects a lot of data, and has high resolution, which is conducive to discovering the difference between subtle faults and normal conditions; it collects a variety of signal types and can realize the test and analysis of acceleration, velocity and displacement at the same time; the data preservation and portability are good, and it can output a variety of file formats; it has good stability and strong anti-interference ability.

[0199] The computer is used as a terminal device. The driver and related software of the DH5992D multi-channel dynamic signal acquisition and analysis instrument are installed inside the computer. It is connected to the acquisition and analysis instrument to display the vibration signal waveform and other analysis results in real time, and store the collected data in the computer.

[0200] The software part is an important part of the reactor vibration experiment, including communication protocols, underlying driver programs, etc., integrating data acquisition, order analysis, basic analysis, experimental modal analysis, impact waveform detection, on-site dynamic balance, acoustic analysis and other analysis and processing and engineering application functions. The use of partitioned management modules is simpler and more convenient, with programmable instrument range, identification of system parameters and setting of sampling parameters, which can complete real-time signal acquisition, analysis and processing, and complete functional modular management, virtual instrument and other operations.

[0201] It can realize data processing functions such as spectrum analysis, 3D model diagram, color cloud diagram, color waterfall diagram, cepstrum analysis, digital filtering, strain stress, mathematical operation, drawing, signal generation, modal parameter identification, etc., to meet the needs of reactor vibration signal analysis to the greatest extent.

[0202] The vibration of the reactor is a simple harmonic motion from the inside to the outside. There are differences in the vibration signals of the normal state and the fault state in the time domain and the frequency domain. The vibration characteristics can be studied through signal processing methods, and the internal faults of the reactor can be diagnosed based on the vibration method.

[0203] In order to comprehensively and specifically analyze the vibration characteristics of the reactor and study its internal faults based on the vibration method, vibration experiments were carried out on the reactor under three working conditions, including normal state, 60% looseness of the winding core, and complete looseness of the winding core.

[0204] (1) Collect the internal and external vibration signals of the reactor in normal state. The experiment fixed the piezoelectric acceleration vibration sensor inside and on the surface of the reactor by binding adhesion and magnet adsorption. Figure 6 As shown, the external measuring points are Figure 7 As shown. The signal acquisition instrument converts the charge signal output by the acceleration vibration sensor into a voltage signal, and then transmits and stores the data in the computer. The sampling frequency of this piezoelectric acceleration vibration sensor is set to 16000Hz. The experimental process adopts a step-by-step voltage increase method, which is set to 10 voltage levels of 20%, 40%, 60%, 80%, 100%, 110%, 120%, 130%, 140%, and 150% of the rated voltage.

[0205] (2) Collect the internal and external vibration signals of the reactor winding core loosening by 60%. According to the internal structural characteristics of the equivalent model of the special reactor, the clamping force of the loose through-core screw is used to simulate the fault state of the winding core loosening by 60%.

[0206] (3) Collect the internal and external vibration signals of the reactor winding core completely loose state. According to the internal structural characteristics of the equivalent model of the special reactor, the winding core completely loose fault state is simulated by setting the clamping force of the through-core screw to 0. The specific fault simulation experiment process is consistent with (2), and the measurement points and collection process are consistent with (1).

[0207] Secondly, this embodiment adopts LabVIEW software design, connects the acceleration vibration sensor, signal acquisition instrument and industrial computer and other hardware parts, collects the voltage, current and vibration signals of the reactor, and monitors and analyzes the reactor status in real time online to form a corresponding monitoring system. This system can realize multiple functions such as signal acquisition, data analysis, result display and result storage, including hardware and software. The overall design block diagram of the system is shown in the figure. Figure 8 shown.

[0208] Among them, (1) signal acquisition: the vibration signal of the reactor in operation is collected by a piezoelectric acceleration vibration sensor, and the real-time signal is displayed on the interface, which is convenient for subsequent analysis and storage.

[0209] (2) Data analysis: The vibration signal is processed using time domain analysis and frequency domain analysis methods to extract relevant effective characteristic states and form characteristic vectors as an effective basis for judging the operating status of the reactor.

[0210] (3) Status diagnosis: Artificial intelligence, threshold method and other decision-making diagnosis methods are used to compare and analyze the characteristic vectors under the operating state and the characteristic vectors under the normal state, and finally make an accurate judgment on the reactor status, realizing various status alarm functions such as reactor abnormality and fault.

[0211] (4) Result display: The interface can display a variety of signal results, including real-time frequency domain signals, signals after data processing, diagnostic results, and alarm prompts.

[0212] (5) Result storage: Based on the reactor's operating status and its own needs, various signals and diagnostic results are selected and stored for subsequent historical review and analysis.

[0213] The monitoring and diagnosis system of the present application presents the characteristics of overall design and block display. The overall system is designed in a unified manner, with appropriate hardware and software designed with a user-friendly interface; in the interface, each part is displayed in blocks and regional groups, and a variety of processing results can be displayed.

[0214] Hardware options include:

[0215] Monitoring quantity and sensor:

[0216] Current: Clamp-type current sensor, Hall current sensor

[0217] Voltage: Hall voltage sensor

[0218] Vibration: ICP-AC102-1A piezoelectric accelerometer vibration sensor

[0219] MPS-140801 signal acquisition instrument and industrial computer.

[0220] The ICP-AC102-1A piezoelectric acceleration vibration sensor not only meets the requirements of high sensitivity, wide frequency response range and strong anti-interference ability, but also has a magnetic disk with huge adsorption force installed at the bottom, which can achieve the purpose of long-term adhesion to the surface of the reactor in the external environment without falling off.

[0221] The MPS-140801 signal acquisition instrument has a built-in conditioning circuit, eliminating the trouble of installing an external conditioning circuit; it has a variety of filters built in to filter and reduce noise on the signal to the greatest extent; the overall size is small and light, making it easy to carry.

[0222] The industrial computer not only has the ability to resist strong magnetic interference, but also has the ability to work in complex external environments, which fully meets the operating conditions of the reactor in conditions of high magnetic field intensity and many uncertain factors.

[0223] LabVIEW is a program development environment and a graphical programming language, which consists of three parts: front panel, block diagram and connector.

[96] .

[0224] The front panel is the user interface, which contains two types of interactive input and output objects, namely controllers and displays. Controllers are switches, buttons, text boxes and other devices, and users can click and input parameters at will; displays are icons, graphics, LEDs and other devices, which are used to output the results of analysis and calculation.

[0225] A flowchart is a graphical source code and a logic circuit used to control and manipulate the input and output functions on the front panel, including the controllers and displays on the front panel, as well as connections, structures, functions, etc. that are not displayed on the front panel.

[0226] A linker is a graphical list of subroutines and their calling parameters.

[0227] Based on the above introduction, combined with the requirements of reactor vibration monitoring and diagnosis, the LabVIEW platform is selected as the software development, which has the following characteristics:

[0228] (1) Simple programming. The LabVIEW platform does not require memorizing programming languages. Instead, it uses visual graphics to connect and complete various functions specified by the user, which is convenient and fast.

[0229] (2) Strong functionality. It eliminates the need for hardware processing and has multiple functional modules.

[0230] (3) Short development cycle. Since hardware production is omitted and control and result display are performed only through graphics on the front panel, the development cycle is greatly shortened.

[0231] (4) Highly customizable. Chip-level hardware functions can be customized in measurement and control applications, and can be quickly updated and expanded based on actual conditions.

[0232] (5) Good portability. It can be run on different computers and used for multiple purposes.

[0233] The reactor monitoring and diagnosis system software consists of five functional modules, namely signal display, data analysis, diagnostic record, storage setting and threshold setting. The system software design flow chart is as follows: Fig. 9 shown.

[0234] Connect the sensor, signal acquisition instrument and industrial computer, start the interface acquisition button to collect signals, and the vibration signal is displayed on the interface in real time; through data processing methods, the results are displayed on the interface in both digital and graphical forms, which is convenient for users to view and analyze; at the same time, the results of data processing are used as the characteristic vector of the diagnostic decision-making method to judge the state of the reactor; finally, the user can save the results on the computer according to needs.

[0235] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0236] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0237] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor, characterized in that: The method includes: Analyze the vibration characteristics of the dry-type reactor, and decompose the magnetic field established by the dry-type reactor, wherein the decomposition direction is along the radial direction and the axial direction of the winding. The radial magnetic field and the current interact to generate an axial electromotive force, and the axial magnetic field and the current interact to generate a radial electromotive force. Under the action of the electromotive force, the winding vibrates; Considering the influence of axial electromotive force on the vibration of the reactor, the axial vibration of the winding is equivalent to a multi-degree-of-freedom mass-spring-damper model, and the axial winding motion equation is constructed based on the multi-degree-of-freedom mass-spring-damper model, wherein the winding is a coil-wound coil structure constituting a mass unit, the insulating spacers between the coils constitute a spring unit, and other external factors of the reactor constitute a damping unit; Then, the influence of winding clamping force on winding looseness and the relationship between the natural frequency of the reactor and the clamping force are determined, so as to calculate the vibration response characteristics of the reactor under different clamping forces when energized, find out the vibration signal with obvious fault characteristics, and compare it with the test results when the winding is working to diagnose whether there is a fault inside the reactor.

2. The winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to claim 1 is characterized in that: The vibration characteristics of the dry-type reactor include: The vibration of the dry-type reactor is generated by the cooling system and the body. The vibration of the cooling system is caused by the rotation of the heat sink and the fan. The vibration of the body includes the vibration of the winding and the iron core. The vibration of the winding is generated by the contact between the cardboard, the pad and the iron core, and the generated vibration signal is transmitted to the surface of the reactor. The winding is divided into multiple layers of coils, each layer of coils is wound by multiple turns of coils, and the overall structure is cylindrical.

3. The winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to claim 2 is characterized in that: The multi-degree-of-freedom mass-spring-damper model includes constructing an axial winding motion equation, including: Among them, z1, z2, ... z n-1 、z n are the axial displacements of each coil, m1, m2, ...m n-1 、m n are the mass of each coil, F a1 、F a2 ,……F a(n-1) 、F an are the axial electromotive forces on each coil, c1, c2, ... c n-1 、c n are the damping coefficients of each coil of the reactor, k t , k1……k n-1 , k b are the elastic coefficients between the insulating pads of the wire cakes, and g is the acceleration of gravity; It is expressed in matrix form as: in, According to the actual operation status of the reactor, the parameters in formula (2) are reasonably simplified and equivalent, assuming that the axial displacement of each coil is equal, that is, z1 = z2 = ... = z n-1 =z n =z; the mass of each coil is equal, that is, m1 = m 2＝ ……=m n-1 =m n =m; the damping coefficient of each coil of the reactor is equal, that is, c1 = c 2＝ ……=c n-1 =c n = c; the elastic coefficients between the insulating pads of the wire cake are equal, k t =k1=……=k n-1 =k b = k, so after addition, it is expressed as: Among them, M = nm is the mass of the coil, C = nc is the damping coefficient of the reactor coil, K = k t +k b =2k is the elastic coefficient of the insulating pad, z are the acceleration, velocity and displacement of the axial motion of the coil, Axial electric force.

4. The winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to claim 3 is characterized in that: The determining of the influence of the winding pressing force on the winding loosening includes: First, according to the law of electromagnetic induction and the left-hand rule, assuming that the current I = I0cos(ω0t), the axial electromotive force on the winding is: Wherein, k is the calculation parameter; I0 is the current amplitude, ω0 is the angular frequency; Therefore, the electromotive force on the axial direction of the reactor winding is the superposition of an AC component twice the industrial frequency and a DC component. Since the DC component electromotive force is equivalent to a constant force, this electromotive force is negligible relative to the axial clamping force. Therefore, the reactor is acted on by the AC component electromotive force in the axial direction, and the frequency is 100Hz. At the same time, due to the complex structure of the winding and the influence of the nonlinear factors of the magnetization curve, the vibration frequency of the winding is 100Hz and its multiples. Combining formula (3) and (4) it can be expressed as: Among them, the size of the elastic coefficient K of the insulating spacer is related to the degree of compression of the reactor winding. During the stable operation of the reactor, the compression force on the winding is constant, that is, when the reactor is in a stable state, the elastic coefficient K can be equivalent to a constant. Therefore, under the condition of a certain winding mass, the natural frequency of the winding can be changed by changing the elastic coefficient of the insulating spacer, that is, changing the degree of compression of the winding, so as to achieve the purpose of making the natural frequency of the winding away from the electromotive force frequency and its multiples, thereby avoiding resonance.

5. The winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to claim 4, characterized in that: Changing the pressing degree of the winding to change the natural frequency of the winding, so as to make the natural frequency of the winding far away from the electrodynamic frequency and its multiple frequencies, thereby avoiding the resonance phenomenon, including: The solution of the non-homogeneous linear differential equation with constant coefficients is the general solution of the homogeneous equation plus the particular solution of the non-homogeneous equation. Therefore, the homogeneous equation corresponding to formula (5): The general solution is: Where: p, is a parameter related to the initial state of the winding, f=λ / (2π) is the natural frequency of the winding and complies with 4MK>>C 2 ,Right now The non-homogeneous equation is decomposed into 2: The particular solutions are obtained respectively as: In the formula: Therefore, the general solution of equation (9) is obtained: Taking the second derivative of formula (10) respectively, the axial vibration acceleration of the winding can be obtained: According to the above, the natural frequency of the winding is f = λ / (2π), The winding also vibrates at a frequency of 100 Hz and its multiples, as well as the expression for the vibration acceleration.

6. The winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to claim 5, characterized in that: Calculating the vibration response characteristics of the reactor under different pressing forces when it is energized, and finding the vibration signals with obvious fault characteristics, including: Since the pressing force of the winding increases, the elastic coefficient K increases, and the natural frequency f of the winding increases; when the pressing force of the winding decreases, the elastic coefficient K decreases, and the natural frequency f of the winding decreases, but the relationship between the natural frequency f of the winding and the electrodynamic vibration frequency f0 = 2ω0 / (2π) = 100Hz is unknown. Therefore, the following conclusions are drawn: (1) If f < f0, the vibration amplitude of the winding increases with the increase of the pressing force, and the resonance phenomenon will not occur, but it is necessary to prevent the natural frequency of the winding from reaching the critical frequency of the electrodynamic fundamental frequency of 100Hz during the process of increasing the pressing force; (2) If f = f0, the natural frequency of the winding is the same as the electrodynamic frequency, thus the resonance phenomenon occurs, resulting in strong vibration. If the reactor operates for a long time in this case, it will cause the winding to loosen and trigger internal mechanical failures; (3) If f > f0, the vibration amplitude of the winding shows a periodic characteristic of first decreasing and then increasing with the increase of the pressing force; it decreases first because the natural frequency of the winding gradually moves away from 100Hz and its multiple frequencies; it increases later because the natural frequency of the reactor winding gradually approaches the multiple frequency of 100Hz; Therefore, if the pressing force is too small, the winding will not have a resonance phenomenon, but it will also cause insufficient pressing force of itself and produce looseness; if the pressing force is too large, while moving away from the 100Hz frequency, it is easy to approach the multiple frequency of 100Hz and produce a resonance phenomenon. Therefore, it is necessary to reasonably calculate and select an appropriate pressing force to ensure the normal operation of the reactor winding and not cause looseness.

7. The winding vibration analysis method based on the vibration propagation characteristics of a dry-type reactor according to claim 3, characterized in that: The electric force F on the axial direction of the coil an It is obtained by superposition of the axial electromotive force received by each layer of coils, which is generated by the interaction between the radial component of magnetic induction intensity and the current. The radial component is expressed as: in, W is the total number of coils in the current coil, t∈[1,W], n j is the coefficient of magnetic induction intensity formed by the j-th layer coil, 0 is the vacuum magnetic permeability, r i 、r j is the winding radius of the i-th and j-th coils, H j is the winding height of the j-th layer coil, and i≠j, z is the Z-axis value corresponding to the j-th layer coil, and the bottom center of the coil is used as the coordinate point, and the X, Y, and Z axes are set respectively. The positive direction of the Z axis is the direction from the center of the bottom coil to the center of the top coil along the coil. Therefore, according to Ampere's law and superposition theorem, the radial component B of the magnetic induction intensity is determined. r The distribution of (t).

8. A winding vibration analysis system based on the vibration propagation characteristics of a dry-type reactor, characterized in that: The system includes: A vibration characteristic analysis module, which is used to analyze the vibration characteristics of the dry-type reactor, decompose the magnetic field established by the dry-type reactor, and the decomposition directions are along the radial and axial directions of the winding. The radial magnetic field and current interact to generate axial electrodynamic force, and the axial magnetic field and current interact to generate radial electrodynamic force. Under the action of the electrodynamic force, the winding generates vibration; A model construction module, which is used to consider the influence of the axial electrodynamic force on the vibration of the reactor, equivalent the axial vibration of the winding to a multi-degree-of-freedom mass-spring-damping model, and construct an axial winding motion equation based on the multi-degree-of-freedom mass-spring-damping model. Among them, the winding is composed of mass units in the form of coil-wound pancakes, the insulating pads between the pancakes form spring units, and other external factors of the reactor form damping units; The fault determination module is used to determine the impact of the winding clamping force on the winding looseness and the relationship between the natural frequency of the reactor and the clamping force, so as to calculate the vibration response characteristics of the reactor under different clamping forces when energized, find out the vibration signal with obvious fault characteristics, and compare it with the test results when the winding is working, diagnose whether there is a fault inside the reactor, and further determine the fault location.

9. The winding vibration analysis system based on the vibration propagation characteristics of dry-type reactor according to claim 8, characterized in that: In the vibration characteristic analysis module, the vibration characteristics of the dry-type reactor include: The vibration of the dry-type reactor is generated by the cooling system and the body. The vibration of the cooling system is caused by the rotation of the heat sink and the fan. The vibration of the body includes the vibration of the winding and the iron core. The vibration of the winding is generated by the contact between the cardboard, the pad and the iron core, and the generated vibration signal is transmitted to the surface of the reactor. The winding is divided into multiple layers of coils, each layer of coils is wound by multiple turns of coils, and the overall structure is cylindrical.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a winding vibration analysis program based on the vibration propagation characteristics of a dry-type inductor. When the winding vibration analysis program based on the vibration propagation characteristics of a dry-type inductor is executed by a processor, the steps of the winding vibration analysis method based on the vibration propagation characteristics of a dry-type inductor as described in any one of claims 1 to 7 are implemented.

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