CN117470363A - Iron core vibration digital acquisition equipment of transformer - Google Patents

Abstract

The invention provides iron core vibration digital acquisition equipment of a transformer, which belongs to the technical field of transformer vibration monitoring and comprises a laser transmitter, a photosensitive resistor plate, a reflective coating and a control chip, wherein the reflective coating is coated on the iron core surface of the transformer, the laser transmitter is arranged on the first inner wall surface, the photosensitive resistor plate is arranged on the second inner wall surface, the incident angle between laser emitted by the laser transmitter and the plane where the reflective coating is positioned is an obtuse angle, and the photosensitive resistor plate is used for receiving laser reflected by the reflective coating and converting the received laser into electric signal pulses; the photosensitive resistor plate comprises a substrate, the substrate is fixedly arranged on the second inner wall, an ammeter and at least 1 photosensitive resistor are arranged on the substrate, the ammeter is electrically connected with a control chip, the control chip comprises an acquisition module and a processing module, the acquisition module is used for acquiring electric signal pulses of the ammeter, and the processing module is used for converting the acquired electric signal pulses into vibration data.

Description

Iron core vibration digital acquisition equipment of transformer

Technical Field

The invention belongs to the technical field of transformer vibration monitoring, and particularly relates to iron core vibration digital acquisition equipment of a transformer.

Background

Transformers are important devices in electrical power systems, the interior of which mainly consists of an iron core and windings. In order to avoid dielectric breakdown caused by contact of the windings with air, dielectric oil needs to be filled in the transformer to perform the functions of insulation and cooling. Typical dielectric oils include mineral oils and silicone oils. When the transformer works under the load state, alternating magnetic induction is generated to act on the iron core, so that the iron core generates magnetostriction effect to generate mechanical vibration and noise. The main reasons are that 1) fluctuation of power supply voltage and current can cause the magnetic density of the iron core to change, and vibration is generated. 2) The magnetostrictive properties of the core material itself can also cause vibrations. 3) The non-uniformity of the core structure and seam gap is also one source of vibration. Vibration of a transformer is one of important reference data for analyzing the running condition of the transformer, and a traditional transformer iron core vibration acquisition mostly adopts a contact type sensor, such as a capacitive acceleration sensor and the like, so that the sensor is difficult to capture tiny vibration, and the obtained vibration data is incomplete.

Disclosure of Invention

In view of the above, the invention provides a digital acquisition device for iron core vibration of a transformer, which can solve the technical problem that the prior art cannot catch the tiny vibration of the iron core of the transformer and the obtained vibration data is incomplete.

The invention is realized in the following way:

the invention provides iron core vibration digital acquisition equipment of a transformer, which comprises a laser emitter, a photosensitive resistor plate, a reflective coating and a control chip, wherein the reflective coating is coated on the iron core surface of the transformer, the laser emitter is arranged on the first inner wall surface, the photosensitive resistor plate is arranged on the second inner wall surface, the first inner wall and the second inner wall are two inner walls which are symmetrical in the transformer, the incident angle between laser emitted by the laser emitter and the plane of the reflective coating is an obtuse angle, and the photosensitive resistor plate is used for receiving laser reflected by the reflective coating and converting the received laser into electric signal pulses; the photoresistor plate comprises a substrate, the substrate is fixedly arranged on the second inner wall, an ammeter and at least 1 photoresistor are arranged on the substrate, and when the number of the photoresistors exceeds 1, the photoresistors are closely distributed; the positive electrode and the negative electrode of the at least 1 photoresistor are respectively connected to the positive input end and the negative input end of the ammeter, the ammeter is electrically connected with the control chip, the control chip comprises an acquisition module and a processing module, the acquisition module is used for acquiring electric signal pulses of the ammeter, and the processing module is used for converting the acquired electric signal pulses into vibration data.

The iron core vibration digital acquisition equipment of the transformer has the technical effects that: the amplitude of the vibration of the iron core is converted into a laser reflection path length change value, the laser reflection path length change value is converted into the brightness change of laser receiving due to the attenuation of oil in the transformer to laser transmission, the vibration of the iron core is described by adopting the brightness change, and due to the fact that the recording frequency of an electric signal is higher, all the vibration can be recorded, and the problem that tiny vibration cannot be captured is avoided.

On the basis of the technical scheme, the iron core vibration digital acquisition equipment of the transformer can be improved as follows:

wherein, the included angle between the plane of the photosensitive resistor plate and the reflected laser beam of the reflective coating is 80-100 degrees.

The beneficial effects of adopting above-mentioned improvement scheme are: the included angle between the reflected laser and the photosensitive resistor plate is close to a right angle, and the reflected laser receiving device is beneficial to realizing more accurate reflected laser receiving.

Furthermore, the included angle between the plane of the photoresistor plate and the reflected laser beam of the reflective coating is a right angle, and the light-receiving surface of at least 1 photoresistor arranged on the photoresistor plate can cover the irradiation range of the reflected laser beam caused by vibration of the reflective coating.

Further, the incidence angle between the laser emitted by the laser emitter and the plane where the reflective coating is located is 160-175 degrees.

The beneficial effects of adopting above-mentioned improvement scheme are: the larger the incident angle is, the more concentrated the incident point of the reflected laser light on the photosensitive resistor plate is, and the less ampere meters can be used for receiving the reflected laser light.

Wherein the laser emitter emits blue laser.

The beneficial effects of adopting above-mentioned improvement scheme are: blue laser light is more attenuated by the oil, and the laser brightness variation caused by the variation of the laser path length is more obvious.

Further, the acquisition frequency of the signal pulses is at least 20MHZ.

The beneficial effects of adopting above-mentioned improvement scheme are: the high frequency pulse acquisition frequency can avoid missing small shocks.

Further, the processing module is configured to perform the following steps:

s10, carrying out noise reduction pretreatment on each acquired electric signal pulse to obtain pretreated signal pulses;

s20, obtaining the maximum value and the minimum value of the preprocessing signal pulse;

s30, according to the maximum amplitude of the transformer core, which is measured in advance, a mapping relation is established between the maximum wave crest and the maximum wave trough of the maximum amplitude of the core and the maximum value and the minimum value of all the pretreatment signals;

s40, converting all pretreatment signal pulses into an iron core vibration time sequence vector set according to the established mapping relation;

s50, outputting the iron core vibration time sequence vector set to a worker.

Further, the step of performing noise reduction pretreatment on each collected electric signal pulse specifically includes:

taking a plurality of electric signal pulses as an original signal;

filtering high-frequency noise pulses in the original signal by using a digital low-pass filter;

zero-phase digital filtering is carried out on the filtered original signal to obtain a filtered signal;

calculating the mean value and standard deviation of the filtered signals;

and carrying out mean variance normalization on the filtered signals to obtain preprocessed signals.

Further, the established mapping relationship is linear mapping.

Further, the step of converting all the preprocessed signal pulses into the time sequence vector set of the vibration of the core specifically includes:

extracting the amplitude value of the sampling point of each preprocessing signal pulse to form a signal vector;

mapping each signal vector to a corresponding iron core vibration vector according to the obtained mapping relation;

and combining all the iron core vibration vectors to form a time sequence matrix.

Compared with the prior art, the iron core vibration digital acquisition equipment of the transformer has the beneficial effects that: the vibration amplitude of the iron core is converted into the current of the electric signal, and small changes can not be missed due to the large change recording frequency of the electric signal, so that the device can capture the tiny vibration and ensure the integrity of the obtained vibration data.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art, so that in order to be able to distinguish the position change state of the iron core in the drawings, the corresponding drawings use color drawings.

Fig. 1 is a schematic structural diagram of a digital acquisition device for iron core vibration of a transformer;

FIG. 2 is a schematic structural view of a photo-resist plate;

FIG. 3 is a schematic diagram of vibration digitization acquisition;

in the drawings, the list of components represented by the various numbers is as follows:

11. a first inner wall; 12. a second inner wall; 21. a core; 22. a reflective coating; 31. a laser emitter; 32. a photosensitive resistor plate; 320. a substrate; 321. a photoresistor; 322. an ammeter.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

1-2, in this embodiment, the device includes a laser emitter 31, a photosensitive resistor plate 32, a reflective coating 22 and a control chip, where the reflective coating 22 is coated on the surface of the iron core 21 of the transformer, the laser emitter 31 is disposed on the surface of the first inner wall 11, the photosensitive resistor plate 32 is disposed on the surface of the second inner wall 12, the first inner wall 11 and the second inner wall 12 are two symmetrical inner walls in the transformer, the incident angle between the laser emitted by the laser emitter 31 and the plane of the reflective coating 22 is an obtuse angle, and the photosensitive resistor plate 32 is used to receive the laser reflected by the reflective coating 22 and convert the received laser into an electrical signal pulse; the photoresistor plate 32 comprises a substrate 320, the substrate 320 is fixedly arranged on the second inner wall 12, an ammeter 322 and at least 1 photoresistor 321 are arranged on the substrate 320, and when the number of the photoresistors 321 exceeds 1, the photoresistors 321 are closely distributed; the positive pole and the negative pole of at least 1 photoresistor 321 are connected respectively on the positive and negative input of ampere meter 322, and ampere meter 322 is connected with the control chip electricity, including collection module and processing module on the control chip, collection module is used for gathering the electrical signal pulse of ampere meter 322, and processing module is used for converting the electrical signal pulse of gathering into vibration data. The plane of the photo-resist plate 32 is at an angle of 80 deg. to 100 deg. to the reflected laser beam of the reflective coating 22. The plane of the photoresistor plate 32 is at right angles to the reflected laser beam of the reflective coating 22, and the light-receiving surface of at least 1 photoresistor 321 disposed on the photoresistor plate 32 can cover the irradiation range of the reflected laser beam caused by the vibration of the reflective coating 22. The incident angle of the laser light emitted from the laser emitter 31 to the plane of the reflective coating 22 is 160 deg. to 175 deg.. The acquisition frequency of the signal pulses is at least 20MHZ. The laser emitter 31 emits blue laser light. In fig. 2, the circuits represented by the different colors are not connected.

The processing module is used for executing the following steps:

s10, carrying out noise reduction pretreatment on each acquired electric signal pulse to obtain pretreated signal pulses;

s20, obtaining the maximum value and the minimum value of the preprocessing signal pulse;

s30, according to the maximum amplitude of the transformer core, which is measured in advance, a mapping relation is established between the maximum wave crest and the maximum wave trough of the maximum amplitude of the core and the maximum value and the minimum value of all the pretreatment signals;

s40, converting all pretreatment signal pulses into an iron core vibration time sequence vector set according to the established mapping relation;

s50, outputting the iron core vibration time sequence vector set to a worker.

Further, in the above technical solution, the step of performing noise reduction pretreatment on each collected electric signal pulse specifically includes:

taking a plurality of electric signal pulses as an original signal;

filtering high-frequency noise pulses in the original signal by using a digital low-pass filter;

zero-phase digital filtering is carried out on the filtered original signal to obtain a filtered signal;

calculating the mean value and standard deviation of the filtered signals;

and carrying out mean variance normalization on the filtered signals to obtain preprocessed signals.

Further, in the above technical solution, the established mapping relationship is a linear mapping.

Further, in the above technical solution, the step of converting all the preprocessed signal pulses into the core vibration timing vector set specifically includes:

extracting the amplitude value of the sampling point of each preprocessing signal pulse to form a signal vector;

mapping each signal vector to a corresponding iron core vibration vector according to the obtained mapping relation;

and combining all the iron core vibration vectors to form a time sequence matrix.

The following describes in detail some of the steps of the process module:

step S10 is to perform noise reduction preprocessing on each collected electric signal pulse to obtain preprocessed signal pulses. The specific implementation mode is as follows:

first, some variables and constants are defined:

x (n) -acquired original signal pulse, wherein n represents sampling point sequence number

y (n) -pre-processed signal pulses

N-signal pulse sampling point number

Impulse response of w (n) -designed digital low-pass filter

Length of M-filter

Then, noise reduction pretreatment is performed:

a digital low-pass filter w (n) is designed to eliminate high-frequency noise by measuring and empirically estimating the effective band range of the original signal x (n). The filter is designed by FIR (finite impulse response) with length M.

Zero-phase digital filtering is carried out on the original signal x (n) to obtain a filtered signal

Computing a filtered signalMean μ and standard deviation of (2)σ:

Carrying out mean variance normalization on the filtered signals to obtain preprocessed signals y (n):

the purpose of normalization is to make the signal have zero mean and unit variance, which is beneficial to the subsequent feature extraction and analysis.

The processing realizes noise reduction and normalized pretreatment of the original signal pulse, filters high-frequency noise, and improves the effective signal characteristics. The signal y (n) obtained after the pretreatment will enter the next step for maximum and minimum extraction.

Step S30 is to establish a mapping relation between the maximum peak and the maximum trough of the maximum amplitude of the iron core and the maximum value and the minimum value of all the pretreatment signals according to the maximum amplitude of the pre-measured transformer iron core. The specific implementation mode is as follows:

variables and constants are first defined:

x _max maximum value of the pre-processed signal pulse

x _min -minimum value of pre-processed signal pulses

y _max Maximum forward amplitude of the transformer core

y _min Maximum negative amplitude of the transformer core

k-mapping scaling factor

b-mapping offset

The following steps are then carried out:

when the transformer works normally, the vibration sensor is used for collecting the vibration signal of the iron core under the condition of maximum load, and the iron core is measuredMaximum forward amplitude y of (2) _max And maximum negative amplitude y _min 。

Global search is carried out on the preprocessed signal pulse to obtain the maximum value x of all the pulses _max And a minimum value x _min 。

Calculating a scaling factor k of the mapping:

calculating the offset b of the mapping:

b＝y _max -k·x _max

using the proportional relationship and the offset obtained above, a mapping relationship between the preprocessing signal x (n) and the core amplitude y (n) is established:

y(n)＝k·x(n)+bforn＝0,1,2,...,N-1

where N is the number of samples of the pre-processed signal pulse.

In this way, the maximum amplitude information of the iron core obtained by measurement is mapped into the amplitude range of the preprocessing signal, and the corresponding relation between the actual physical quantity and the signal quantity is realized.

The method establishes the proportional relation between the vibration amplitude of the transformer iron core and the amplitude of the preprocessing signal according to the maximum and minimum values by utilizing the thought of linear mapping, and provides a basis for the follow-up restoration of the actual iron core vibration according to the preprocessing signal.

Step S40 is to convert all the preprocessed signal pulses into a time sequence vector set of core vibration according to the established mapping relation.

The specific embodiment is as follows:

definition of variables

x (N) -nth pre-processing signal pulse, n=1, 2,..

y (n) -corresponding nth core vibration timing vector

The mapping scaling factor and offset determined in the k, b-S30 step

For each preprocessing signal pulse x (n), extracting the amplitude of a sampling point to form a vector:

where L is the number of samples per pulse.

According to the mapping relation obtained in the step S30, each preprocessing signal pulse vector is processedMapping to core vibration timing vector y (n):

the unfolding is as follows:

y(n,1)＝k*x(n,1)+b

y(n,2)＝k*x(n,2)+b

...

y(n,L)＝k*x(n,L)+b

all the vibration time sequence vectors of the iron coreIn combination, a core vibration timing vector set Y is formed:

and outputting the iron core vibration time sequence vector set Y, and completing conversion from the preprocessing signal to the iron core vibration.

In this way, according to the mapping relation established in S30, each preprocessing signal pulse can be converted to the corresponding iron core vibration time sequence, so as to realize the restoration from the acquisition signal to the actual iron core vibration.

As shown in fig. 3, the principle of the present invention is: the black iron core 21 represents the first position of the iron core 21, the red iron core 21 represents the second position of the iron core 21, and when vibrating, the iron core 21 is displaced from the first position to the second position to drive the reflective coating 22 to displace, and the incident angle of the laser beam emitted by the laser emitter 31 and the reflective coating 22 is an obtuse angle, so thatThe distance to the photosensitive resistor plate 32 after the laser light is reflected by the reflective coating 22 at different positions is different, such as L in the figure ₀ +L ₁ +L ₃ The laser path of the core 21 at the first position is denoted as a first path, L ₀ +L ₂ The laser path of the core 21 at the second position is denoted as a second path, which is obviously longer than the first path; since the transformer is filled with oil, the laser of the second path attenuates more, and the current of the electric signal pulse generated after reaching the photoresistor plate 32 is lower than that of the laser of the first path; therefore, the device can be utilized to convert the mechanical vibration of the iron core into an electric pulse signal, and further analyze and calculate the electric pulse signal to obtain the vibration data of the iron core. When the incident angle of the incident laser on the reflective coating 22 is larger, the difference between the first path and the second path is larger, so that the current difference of the obtained electric pulse signal is also larger, and the data range for describing vibration is larger, thereby playing a better role in describing vibration; on the other hand, H ₀ And H ₁ As the core vibration amplitude difference, this amplitude difference is significantly smaller than the difference between the first path and the second path, and therefore, the error can be reduced by calculating using the difference between the first path and the second path.

It should be noted that, the reflective coating, the laser emitter, the photoresistor and the ammeter do not need special models, and a worker can choose to use according to the installation condition of the equipment when using the ammeter.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims (10)

1. The iron core vibration digital acquisition equipment of the transformer is characterized by comprising a laser emitter, a photosensitive resistor plate, a reflective coating and a control chip, wherein the reflective coating is coated on the iron core surface of the transformer, the laser emitter is arranged on the first inner wall surface, the photosensitive resistor plate is arranged on the second inner wall surface, the first inner wall and the second inner wall are two symmetrical inner walls in the transformer, the incident angle between laser emitted by the laser emitter and the plane where the reflective coating is located is an obtuse angle, and the photosensitive resistor plate is used for receiving laser reflected by the reflective coating and converting the received laser into electric signal pulses; the photoresistor plate comprises a substrate, the substrate is fixedly arranged on the second inner wall, an ammeter and at least 1 photoresistor are arranged on the substrate, and when the number of the photoresistors exceeds 1, the photoresistors are closely distributed; the positive electrode and the negative electrode of the at least 1 photoresistor are respectively connected to the positive input end and the negative input end of the ammeter, the ammeter is electrically connected with the control chip, the control chip comprises an acquisition module and a processing module, the acquisition module is used for acquiring electric signal pulses of the ammeter, and the processing module is used for converting the acquired electric signal pulses into vibration data.

2. The digital acquisition device for iron core vibration of a transformer according to claim 1, wherein an included angle between a plane of the photosensitive resistor plate and a reflected laser beam of the reflective coating is 80-100 degrees.

3. The digital acquisition device for core vibration of a transformer according to claim 2, wherein an included angle between a plane of the photoresistor plate and a reflected laser beam of the reflective coating is a right angle, and a light-facing surface of at least 1 photoresistor arranged on the photoresistor plate can cover an irradiation range of the reflected laser beam caused by vibration of the reflective coating.

4. A transformer core vibration digital acquisition device according to claim 3, wherein the incident angle between the laser emitted by the laser emitter and the plane of the reflective coating is 160-175 °.

5. The digital acquisition device for core vibration of a transformer according to claim 1, wherein the laser transmitter emits blue laser light.

6. A transformer core vibration digitizing acquisition device according to any of claims 1 to 5, wherein the acquisition frequency of the signal pulses is at least 20MHZ.

7. The digitized acquisition device of core vibrations of a transformer of claim 6 wherein the processing module is configured to perform the steps of:

s10, carrying out noise reduction pretreatment on each acquired electric signal pulse to obtain pretreated signal pulses;

s20, obtaining the maximum value and the minimum value of the preprocessing signal pulse;

s30, according to the maximum amplitude of the transformer core, which is measured in advance, a mapping relation is established between the maximum wave crest and the maximum wave trough of the maximum amplitude of the core and the maximum value and the minimum value of all the pretreatment signals;

s40, converting all pretreatment signal pulses into an iron core vibration time sequence vector set according to the established mapping relation;

s50, outputting the iron core vibration time sequence vector set to a worker.

8. The digital acquisition device for core vibration of a transformer according to claim 7, wherein the step of performing noise reduction pretreatment on each acquired electric signal pulse comprises:

taking a plurality of electric signal pulses as an original signal;

filtering high-frequency noise pulses in the original signal by using a digital low-pass filter;

zero-phase digital filtering is carried out on the filtered original signal to obtain a filtered signal;

calculating the mean value and standard deviation of the filtered signals;

and carrying out mean variance normalization on the filtered signals to obtain preprocessed signals.

9. The digitized acquisition apparatus of claim 7 wherein the established mapping relationship is a linear mapping.

10. The digitized acquisition apparatus of core vibrations of a transformer of claim 7 wherein the step of converting all of the preprocessed signal pulses into a set of core vibration timing vectors comprises:

extracting the amplitude value of the sampling point of each preprocessing signal pulse to form a signal vector;

mapping each signal vector to a corresponding iron core vibration vector according to the obtained mapping relation;

and combining all the iron core vibration vectors to form a time sequence matrix.