CN110988523A - Method and device for detecting cumulative effect of winding deformation of power transformer - Google Patents

Abstract

The invention relates to a method for detecting the deformation accumulation effect of a power transformer winding, which comprises the following steps: collecting ultrasonic signals on the surface of a box body in the running process of a power transformer after short circuit impact; carrying out frequency analysis on the ultrasonic signal to obtain a frequency characteristic function of the ultrasonic signal; performing power spectrum estimation on the rate characteristic function to obtain the frequency with the maximum power; calculating the accumulated effect degree of the deformation of the power transformer winding to obtain a parameter of the accumulated effect of the deformation of the power transformer winding; and detecting the degree of the accumulated effect of the deformation of the power transformer winding. The invention also relates to a detection device comprising: the device comprises a signal acquisition module, a signal preprocessing module, a signal processing module and a result judgment module. The method is suitable for detecting the deformation degree of the power transformer winding without power outage, and provides an important basis for evaluating the health level of the power transformer after sudden short circuit impact.

Description

Method and device for detecting cumulative effect of winding deformation of power transformer

technical field

The invention belongs to the technical field of transformer live detection, and in particular relates to a method and a device for detecting the cumulative effect of winding deformation of a power transformer.

Background technique

With the continuous development of industry and economy, people's requirements for electric energy are getting higher and higher, and high-quality and reliable power supply constitutes the basis for the normal operation of modern society. As the key equipment of power transmission and distribution in the power system, power transformers are responsible for the important task of power transmission in the system, especially large-scale high-voltage power transformers are at the pivotal position of the system, and their operational reliability will also directly affect the safety of the power system. with stability. When a short-circuit fault occurs in the transformer, the current value flowing in the winding is relatively large, and the coil is subjected to a large electric force, which leads to the deformation and collapse of the coil, or the inter-turn short circuit caused by the damage of the insulation, the coil is burned, or Putting pressure on the inner coil may lead to bending or dynamic instability of the inner coil. When a short circuit occurs, the mechanical strength of the winding decreases along with the rise of the winding temperature. Even though this transient process is short, the transformer can suffer damage.

After years of transformer operation data analysis, it can be seen that the transformer winding deformation caused by short-circuit impact is one of the important reasons for the damage of the power transformer body. Each short-circuit impact will accumulate different degrees of deformation inside the transformer winding. Therefore, an accurate An efficient evaluation method for the cumulative effect of winding deformation of power transformers after short-circuit impact is of great significance to the safe and stable operation of power transformers.

At present, the main detection methods for judging the deformation of power transformer windings include short-circuit impedance measurement of power transformer windings and winding frequency response method. The related parameters of transformer windings after short-circuit impact are compared with the original data to judge the degree of deformation of power transformer windings. These methods all have the problem that they can only be carried out under the condition of power failure, and cannot detect the degree of winding deformation of the power transformer in the running state, and there are various constraints in practical application.

SUMMARY OF THE INVENTION

The invention is suitable for detecting the deformation degree of the winding of the power transformer without interruption, and provides an important basis for evaluating the health level of the power transformer after a sudden short-circuit impact.

Technical scheme of the present invention:

A method for detecting the cumulative effect of winding deformation of a power transformer, comprising:

Collect the ultrasonic signals on the surface of the box during the operation of the power transformer after being impacted by a short circuit;

Perform frequency analysis on the ultrasonic signal to obtain a frequency characteristic function of the ultrasonic signal;

Perform power spectrum estimation on the rate characteristic function to obtain the frequency with the maximum power;

Calculate the degree of cumulative effect of the winding deformation of the power transformer, and obtain the cumulative effect parameters of the winding deformation of the power transformer;

Detect the degree of cumulative effect of power transformer winding deformation.

Further, the ultrasonic signal acquisition process on the surface of the box body during the operation of the power transformer after being impacted by a short circuit includes:

An ultrasonic sensor is used to collect ultrasonic signals at a specific part of the box surface of the power transformer during operation, wherein the specific part is the surface position closest to the low-voltage winding in the power transformer box.

Further, the ultrasonic signal on the surface of the box body during the operation of the power transformer, the wavelet analysis is performed on the ultrasonic signal, including:

Discretization processing is performed on the ultrasonic signal, and then a specific filtering frequency domain wavelet analysis is performed on the ultrasonic signal to obtain a frequency domain characteristic function of the ultrasonic signal, wherein the specific filtering frequency domain is 20kHz-40kHz.

Further, wherein the ultrasonic signal is specifically filtered by frequency domain wavelet analysis to obtain a frequency domain characteristic function of the ultrasonic signal, including:

In the specific filtering frequency domain, the frequency domain characteristic function of the ultrasonic signal is calculated using the Mallat algorithm:

为尺度系数，

为小波系数，

为信号离散化采样的通过低通滤波器构造的尺度函数，

为信号通过高通滤波器构造的小波函数，J为小波变换级数，j、k为求和系数。

is the scale factor,

is the wavelet coefficient,

The scale function constructed by the low-pass filter sampled for the discretization of the signal,

is the wavelet function constructed by the signal passing through the high-pass filter, J is the wavelet transform series, and j and k are the summation coefficients.

Further, in the specific filtering frequency domain, power analysis is performed on the frequency domain characteristic function f(x):

s(x) is the signal strength amplitude corresponding to the frequency, and T is the signal acquisition time domain length;

In the specific filtering frequency domain, the maximum frequency of signal strength

_si is the amplitude of the signal strength corresponding to the corresponding frequency.

Further, the cumulative effect degree parameter λ=log(f _max /f _ini ) is calculated according to the frequency f _max of the maximum intensity of the ultrasonic signal, and the frequency f _ini of the maximum intensity of the original ultrasonic signal measured by the power transformer.

Further, according to the cumulative effect degree parameter λ, the absolute value |λ| of the cumulative effect degree parameter of the transformer winding deformation is calculated.

Further, judging the degree of cumulative effect of the power transformer includes the following steps:

Judging whether the absolute value of the cumulative effect degree parameter |λ| is in the interval [0, 0.005), if |λ| is in the interval [0, 0.005), it is determined that the power transformer does not have the cumulative effect of winding deformation;

Judging whether the absolute value of the cumulative effect degree parameter |λ| is in the range of [0.005, 0.01), if |λ| is in the range of [0.005, 0.01), it is judged that the power transformer has a slight cumulative effect of winding deformation;

Judging whether the absolute value of the cumulative effect degree parameter |λ| is in the interval [0.01, 0.1), if |λ| is in the interval [0.01, 0.1), it is determined that the power transformer has a general degree of cumulative effect of winding deformation;

It is judged whether the absolute value of the cumulative effect degree parameter |λ| is in the interval [0.1, +∞), if |λ| is in the interval [0.1, +∞), it is judged that the power transformer has a serious cumulative effect of winding deformation.

Further, the probe used by the ultrasonic sensor used for collecting ultrasonic waves on the surface of the transformer is a longitudinal wave ultrasonic probe.

Further, a detection device for the cumulative effect of winding deformation of a power transformer, comprising: a signal acquisition module, a signal preprocessing module, a signal processing module and a result judgment module;

Signal acquisition module: use ultrasonic sensors to collect ultrasonic signals on the surface of the box when the transformer is running;

Signal preprocessing module: including signal filtering module, signal amplification module and signal analog-to-digital converter;

Signal processing module: perform frequency analysis and power spectrum estimation on discretized signals, and calculate the cumulative effect parameters of power transformer winding deformation;

Result judgment module: According to the calculated cumulative effect parameters of the winding deformation of the power transformer, the degree of the cumulative effect of the winding deformation of the power transformer is judged.

Beneficial effects of the present invention:

The invention is suitable for detecting the deformation degree of the winding of the power transformer without interruption, and provides an important basis for evaluating the health level of the power transformer after a sudden short-circuit impact. The calculation method of the invention is simple, and the evaluation result is accurate according to the segmental judgment of the absolute value of the cumulative effect degree parameter.

Description of drawings

FIG. 1 is a schematic block diagram of the device of the present invention.

Detailed ways

The technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that, for the convenience of description, the dimensions of various parts shown in the accompanying drawings are not drawn in an actual proportional relationship. Techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the authorized description. In all examples shown and discussed herein, any specific value should be construed as illustrative only and not as limiting. Accordingly, other examples of exemplary embodiments may have different values. It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further discussion in subsequent figures.

In the description of this application, it should be understood that the orientations indicated by the orientation words such as "front, rear, top, bottom, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" etc. Or the positional relationship is usually based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and these orientations do not indicate or imply the indicated device or element unless otherwise stated. It must have a specific orientation or be constructed and operated in a specific orientation, so it cannot be construed as a limitation on the protection scope of the application; the orientation words "inside and outside" refer to the inside and outside relative to the contour of each component itself.

For ease of description, spatially relative terms, such as "on", "over", "on the surface", "above", etc., may be used herein to describe what is shown in the figures. The spatial positional relationship of one device or feature shown to other devices or features. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or features would then be oriented "below" or "over" the other devices or features under other devices or constructions". Thus, the exemplary term "above" can encompass both an orientation of "above" and "below." The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood to limit the scope of protection of this application.

The technical solutions and structures of the present invention will be described in further detail below with reference to the accompanying drawings.

In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are set forth in order to provide a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to illustrate the technical solutions of the present invention, the following specific embodiments are used for description.

Example 1

Embodiments of the present invention provide a method and device for detecting the cumulative effect of winding deformation of a power transformer. The detection method includes the following steps:

Step 101 , collect ultrasonic signals on the surface of the box during the operation of the transformer.

The longitudinal wave ultrasonic sensor is used to collect the ultrasonic signal on the surface of the box during the operation of the transformer in real time.

The ultrasonic sensor is placed on the surface of the power transformer near the low-voltage winding, and the effective operating frequency of the sensor should include 20kHz-40kHz.

In step 102, the collected ultrasonic signal is subjected to discretization processing.

The analog signal collected by the ultrasonic sensor is input into the ADC analog-to-digital converter after the band-pass filter and signal amplifier, and the continuously changing analog signal is converted into a discrete digital signal with a sampling frequency of 200kHz.

Step 103: Perform frequency analysis on the collected discretized ultrasonic signal.

Wavelet transform (WT) is a new transform analysis method. It inherits and develops the idea of localization of short-time Fourier transform, and at the same time overcomes the shortcomings of window size that does not change with frequency. The Time-Frequency window is an ideal tool for signal time-frequency analysis and processing. Its main feature is that it can fully highlight the characteristics of some aspects of the problem through transformation, can analyze the localization of temporal (spatial) frequencies, and gradually refine the signal (function) through scaling and translation operations. Time subdivision, frequency subdivision at low frequency, can automatically adapt to the requirements of time-frequency signal analysis, so that it can focus on any details of the signal, solve the difficult problem of Fourier transform, and become a major breakthrough in scientific methods since Fourier transform.

Mallat algorithm is an important part of wavelet theory, and it is a fast algorithm that can decompose and reconstruct a function by wavelet. In the derivation of the Mallat algorithm, it is assumed that the input sequence is infinitely long, but in practical applications it is often time-sharing sampling, that is, the input sequence is of finite length. Therefore, it is necessary to carry out boundary continuation of the original signal to reduce the boundary error. The solutions usually include zero-fill continuation and periodic continuation. The periodic extension method expands the original finite-length input sequence into a periodic sequence. Periodic continuation can be applied to any wavelet transform, but it may lead to discontinuity at the edge of the input sequence, making the high-frequency coefficients larger. After convolution, the continuation of this method is consistent with the length of the source signal.

Frequency analysis of discretized ultrasonic signals using Mallat algorithm,

为尺度系数，

为小波系数。in,

is the scale factor,

is the wavelet coefficient.

Step 104, perform power analysis on the frequency domain characteristic function f(x).

Signals are usually in the form of waves, such as electromagnetic waves, random vibrations, or sound waves. When the power spectral density of the wave is multiplied by an appropriate factor, the power carried by the wave per unit frequency is obtained, which is called the power spectral density of the signal.

In the specific filtering frequency domain 20-40kHz, perform power analysis on the frequency domain characteristic function f(x):

In the specific filtering frequency domain, the maximum frequency of signal strength

Step 105: Calculate the cumulative effect degree parameter according to the frequency of occurrence of the maximum intensity of the ultrasonic signal and the initial value.

The frequency of occurrence of the maximum intensity of the ultrasonic signal obtained by the current detection is f _max , and the frequency of occurrence of the maximum intensity of the original ultrasonic signal when the power transformer is factory-measured is f _ini , according to which the cumulative effect degree parameter is calculated

λ=log(f _max /f _ini ).

The degree of cumulative effect is represented by the absolute value of λ |λ|.

Step 106, judging whether the absolute value of the cumulative effect degree parameter |λ| is within the interval [0, 0.005).

If |λ| is in the range of [0, 0.005), it is judged that the power transformer does not have the cumulative effect of winding deformation.

Step 107, judging whether the absolute value of the cumulative effect degree parameter |λ| is within the interval of [0.005, 0.01).

If |λ| is in the range of [0.005, 0.01), it is judged that the power transformer has a slight cumulative effect of winding deformation.

Step 108, judging whether the absolute value of the cumulative effect degree parameter |λ| is within the interval of [0.01, 0.1).

If |λ| is in the interval of [0.01, 0.1), it is judged that the power transformer has a general degree of cumulative effect of winding deformation.

Step 109: Determine whether the absolute value of the cumulative effect degree parameter |λ| is within the interval [0.1, +∞).

If |λ| is in the range of [0.1, +∞), it is judged that the power transformer has a serious cumulative effect of winding deformation.

It should be understood that the size of the sequence numbers of the steps in the above embodiments does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

The method for detecting the cumulative effect of the winding deformation of a power transformer used in the embodiment of the present invention collects the ultrasonic signal on the surface of the box when the transformer is running, performs frequency analysis after discretization processing, and obtains the frequency of occurrence of the maximum intensity of the ultrasonic signal through power spectrum estimation. The frequency of occurrence of the maximum intensity of the ultrasonic signal and the frequency of occurrence of the maximum intensity of the original ultrasonic signal in the factory measurement of the power transformer are calculated to obtain the parameter of the cumulative effect of the winding deformation of the power transformer, and the cumulative effect of the deformation of the power transformer winding is judged.

The embodiment of the present invention also provides a detection device for the cumulative effect of the winding deformation of a power transformer, and the device includes:

The signal acquisition module 201 uses an ultrasonic sensor to collect ultrasonic signals on the surface of the box body when the transformer is running.

Ultrasonic sensors use longitudinal wave sensors, and the wave is the propagation of vibration, which propagates through the medium. In the same homogeneous medium, the propagation of vibration is a uniform linear motion, and this motion is characterized by the wave speed V. Transverse and longitudinal waves are two types of waves, and waves are the propagation of vibrations, propagating through a medium. Shear waves, also known as "concave and convex waves", are those in which the direction of vibration of the particle is perpendicular to the direction of propagation of the wave. A longitudinal wave is a wave in which the direction of vibration of the particle is parallel to the direction of propagation of the wave. Ultrasound is still a sound wave, which is a longitudinal wave propagation mode.

The ultrasonic sensor is placed on the surface of the power transformer near the low-voltage winding, and the effective operating frequency of the sensor should include 20kHz-40kHz.

The signal preprocessing module 202 performs pre-filtering and amplifying processing on the ultrasonic signal obtained by the sensor.

It includes a signal filtering module 2021 , a signal amplification module 2022 and a signal analog-to-digital converter 2023 .

The function of the signal filtering module 2021 is to filter the ultrasonic signal collected by the ultrasonic sensor, so that specific frequency components in the signal can pass through, and other frequency components can be greatly attenuated. Using this frequency selection function of the filter, the interference noise can be filtered out or the spectrum analysis can be performed to filter out the interference factors of the remaining frequency bands.

This module is a band-pass filter, which refers to a filter that can pass frequency components in a certain frequency range, but attenuate frequency components in other ranges to a very low level. The upper cutoff frequency of the filter is 40kHz, and the lower cutoff frequency is 20kHz.

The signal amplification module 2022 amplifies the power of the input ultrasonic signal, which can more accurately process and calculate the signal. It is composed of electronic tubes or transistors, power transformers and other electrical components. For linear amplifiers, the output is the reproduction and enhancement of the input signal. .

The signal analog-to-digital converter 2023 is used to convert the input continuous ultrasonic signal from an analog quantity to a discrete digital quantity.

An analog signal is continuous in the time domain, so it can be converted into a series of digital signals that are continuous in time. This requires defining a parameter to represent the rate at which the new digital signal is sampled from the analog signal. This rate is called the sample rate of the converter.

According to Shannon sampling rate, sampling is the transformation of a signal (ie, a continuous function in time or space) into a sequence of values (ie, a discrete function in time or space). After the discrete signal obtained by sampling is passed through the holder, a stepped signal is obtained, that is, it has the characteristics of a zero-order holder. If the signal is band-limited and the sampling frequency is higher than twice the highest frequency of the signal, then the original continuous signal can be completely reconstructed from the sampled samples

Therefore, in order to restore the analog signal without distortion, the sampling frequency should be no less than 2 times the highest frequency in the spectrum of the analog signal. In general practical applications, the sampling frequency is guaranteed to be 2.56 to 4 times the highest frequency of the signal, and the sampling frequency used in this embodiment is 200 kHz.

The signal processing module 203 : performs frequency analysis and power spectrum estimation on the discretized signal, and calculates the cumulative effect parameter of the winding deformation of the power transformer.

Frequency analysis of discretized ultrasonic signals using Mallat algorithm,

为尺度系数，

为小波系数。in,

is the scale factor,

is the wavelet coefficient.

In the specific filtering frequency domain 20-40kHz, perform power analysis on the frequency domain characteristic function f(x):

In the specific filtering frequency domain, the maximum frequency of signal strength

The frequency of occurrence of the maximum intensity of the ultrasonic signal obtained by the current detection is f _max , and the frequency of occurrence of the maximum intensity of the original ultrasonic signal when the power transformer is factory-measured is f _ini , according to which the cumulative effect degree parameter is calculated

λ=log(f _max /f _ini ).

The degree of cumulative effect is represented by the absolute value of λ |λ|.

Result judgment module 4: According to the calculated cumulative effect parameters of the winding deformation of the power transformer, judge the degree of the cumulative effect of the winding deformation of the power transformer.

It is judged whether the absolute value of the cumulative effect degree parameter |λ| is in the interval of [0, 0.005).

If |λ| is in the range of [0, 0.005), it is judged that the power transformer does not have the cumulative effect of winding deformation.

It is judged whether the absolute value of the cumulative effect degree parameter |λ| is in the interval of [0.005, 0.01).

If |λ| is in the range of [0.005, 0.01), it is judged that the power transformer has a slight cumulative effect of winding deformation.

It is judged whether the absolute value of the cumulative effect degree parameter |λ| is in the interval of [0.01, 0.1).

If |λ| is in the interval of [0.01, 0.1), it is judged that the power transformer has a general degree of cumulative effect of winding deformation.

It is judged whether the absolute value of the cumulative effect degree parameter |λ| is in the interval of [0.1, +∞).

If |λ| is in the range of [0.1, +∞), it is judged that the power transformer has a serious cumulative effect of winding deformation.

Claims (10)

1. a detection method for the cumulative effect of power transformer winding deformation, is characterized in that, it comprises: Collect the ultrasonic signals on the surface of the box during the operation of the power transformer after being impacted by a short circuit; Perform frequency analysis on the ultrasonic signal to obtain a frequency characteristic function of the ultrasonic signal; Perform power spectrum estimation on the frequency characteristic function to obtain the frequency with the maximum power; Calculate the degree of cumulative effect of the winding deformation of the power transformer, and obtain the cumulative effect parameters of the winding deformation of the power transformer; Detect the degree of cumulative effect of power transformer winding deformation. 2. The method for detecting the cumulative effect of winding deformation of a power transformer according to claim 1, wherein the ultrasonic signal collection process on the surface of the box during operation after the short-circuit impact of the power transformer, comprising: An ultrasonic sensor is used to collect ultrasonic signals of a specific part of the box surface of the power transformer during operation, wherein the specific part is the surface position of the power transformer box closest to the low-voltage winding. 3. The method for detecting the cumulative effect of a power transformer winding deformation according to claim 2, wherein the ultrasonic signal on the surface of the box during the operation of the power transformer is subjected to wavelet analysis to the ultrasonic signal, include: The ultrasonic signal is discretized, and then a specific filtering frequency domain wavelet analysis is performed on the ultrasonic signal to obtain a frequency domain characteristic function of the ultrasonic signal, wherein the specific filtering frequency domain is 20kHz-40kHz. 4. The method for detecting the cumulative effect of power transformer winding deformation according to claim 3, wherein the ultrasonic signal is analyzed by a specific filter frequency domain wavelet to obtain a frequency domain characteristic function of the ultrasonic signal, wherein ,include: In the specific filtering frequency domain, the frequency domain characteristic function of the ultrasonic signal is calculated using the Mallat algorithm:

is the scale factor,

is the wavelet coefficient,

The scale function constructed by the low-pass filter of the discretized samples of the signal,

is the wavelet function constructed by the signal passing through the high-pass filter, J is the wavelet transform series, and j and k are the summation coefficients. 5. The detection method for the cumulative effect of a power transformer winding deformation according to claim 4, wherein, in the specific filtering frequency domain, power analysis is performed on the frequency domain characteristic function f(x):

; In the specific filtering frequency domain, the maximum frequency of signal strength

;

Corresponding signal strength amplitude for the corresponding frequency. 6. The method for detecting the cumulative effect of the deformation of a power transformer winding according to claim 5, characterized in that, according to the frequency of occurrence of the maximum intensity of the ultrasonic signal

, and the frequency of occurrence of the maximum intensity of the original ultrasonic signal measured with the power transformer factory

, calculate the cumulative effect degree parameter

. 7. The method for detecting the cumulative effect of the winding deformation of a power transformer according to claim 6, characterized in that, according to the cumulative effect degree parameter

, calculate the absolute value of the parameter of the cumulative effect degree of the transformer winding deformation

. 8. The detection method of a power transformer winding deformation cumulative effect according to claim 7, characterized in that, judging the power transformer cumulative effect degree comprises the steps: Determine the absolute value of the cumulative effect degree parameter

Whether it is in the [0, 0.005) interval, such as

is located in the interval [0, 0.005), it is judged that the power transformer does not have the cumulative effect of winding deformation; Determine the absolute value of the cumulative effect degree parameter

Whether it is in the [0.005, 0.01) interval, such as

If it is in the range of [0.005, 0.01), it is judged that the power transformer has a slight cumulative effect of winding deformation; Determine the absolute value of the cumulative effect degree parameter

Whether it is in the [0.01, 0.1) interval, such as

If it is in the range of [0.01, 0.1), it is judged that the power transformer has a general degree of cumulative effect of winding deformation; Determine the absolute value of the cumulative effect degree parameter

Whether it is in the interval [0.1, +∞), such as

It is located in the [0.1, +∞) interval, it is judged that the power transformer has a serious cumulative effect of winding deformation. 9 . The method for detecting the cumulative effect of winding deformation of a power transformer according to claim 1 , wherein the probe used by the ultrasonic sensor used for collecting ultrasonic waves on the surface of the transformer is a longitudinal wave ultrasonic probe. 10 . 10. A detection device for the cumulative effect of winding deformation of a power transformer, characterized in that it comprises: a signal acquisition module, a signal preprocessing module, a signal processing module and a result judgment module; Signal acquisition module: use ultrasonic sensors to collect ultrasonic signals on the surface of the box when the transformer is running; Signal preprocessing module: including signal filtering module, signal amplification module and signal analog-to-digital converter; Signal processing module: perform frequency analysis and power spectrum estimation on discretized signals, and calculate the cumulative effect parameters of power transformer winding deformation; Result judgment module: According to the calculated cumulative effect parameters of the winding deformation of the power transformer, the degree of the cumulative effect of the winding deformation of the power transformer is judged.

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