KR101410734B1 - Signal precessing device and method for elimination partial discharge noise using FFT - Google Patents

Abstract

The present invention relates to signal processing device and method for eliminating a partial discharge noise using fast Fourier transform (FFT), and more specifically, to signal processing device and method for eliminating a partial discharge noise using FFT in which only a specific region is selected from a frequency region of an ultrasonic signal using an FFT technology to extract only a wanted signal. After only a specific region required as an actual signal is selected and extracted from the frequency region of the ultrasonic signal measured from an object to be measured for the partial discharge by using the FFT technology, the extracted specific region is converted by A/D and then is transmitted to a next process, to optimize the sensitivity of the signal by eliminating the noise of the ultrasonic signal. Therefore, it is possible to improve the accuracy of the data determining the generation position of the partial discharge.

Description

[0001] The present invention relates to a partial discharge noise elimination signal processing apparatus and method using FFT,

The present invention relates to an apparatus and method for removing a partial discharge noise signal using an FFT, and more particularly, to an apparatus and method for removing a partial discharge noise by using an FFT To a partial discharge noise elimination signal processing apparatus and method.

2. Description of the Related Art Generally, a technique for estimating a partial discharge position of a power device is a very important technique for preventing a failure of the power device. In the related art, a method of using the attenuation of an electromagnetic wave discharge signal generated by a discharge And a method of using a time difference in which the electromagnetic wave discharge signal reaches the partial discharge sensor are used. However, only the types of defects of the electric power devices can be estimated, and more importantly, There are disadvantages.

In order to solve this disadvantage, a method of accurately detecting a partial discharge position by detecting an ultrasonic wave by using an ultrasonic sensor has been attempted in order to increase the measurement accuracy of a partial discharge using ultrasonic waves.

Hereinafter, a conventional partial discharge measuring method using ultrasonic waves will be briefly described with reference to FIG.

First, the ultrasonic sensor 10 senses an ultrasonic sound when a partial discharge such as a corona is generated in the partial discharge measurement object.

Then, the ultrasonic signal measured by the ultrasonic sensor 10 is amplified through the ultrasonic amplifier 11, and then filtered by the filtering unit 12. FIG.

Next, the amplified analog signal is converted into a digital signal through the A / D converter 13.

Finally, the digital data based on the digital signal is input to the signal processing unit of the subsequent processing unit 14, and then utilized as data for partial discharge positioning in the subsequent processor of the signal processing unit.

However, even if the ultrasound signal measured by the ultrasonic sensor is filtered, the ultrasound signal waveform (upper yellow and sky blue portions) and the frequency-converted signal waveform (lower yellow and purple portions) The signal inside the quadrangle corresponds to the actual signal and the remainder corresponds to the noise, and as a result, there is a disadvantage that it is insufficient as a signal for grasping the partial discharge position.

Accordingly, even if the filtered ultrasound signal is converted into a digital signal by the A / D converter, there is a disadvantage in that accuracy as data for grasping the location of occurrence of the partial discharge is lowered due to a large amount of noise as well as actual signals.

In addition, since the ultrasonic signal detected by the ultrasonic sensor includes a lot of noise generated from the amplifier or the power supply circuit, the sensitivity of the ultrasonic sensor can not be optimized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an ultrasonic diagnostic apparatus and a method of detecting a partial discharge using a Fast Fourier Transform (FFT) And then converted into A / D and transmitted as a subsequent process for grasping the partial discharge position, whereby the noise of the ultrasonic signal can be removed to optimize the sensitivity of the signal, thereby locating the generation position of the partial discharge And an object of the present invention is to provide a partial discharge noise elimination signal processing apparatus and method using an FFT that improves accuracy as data.

According to an aspect of the present invention, there is provided an ultrasonic diagnostic apparatus comprising: an ultrasonic sensor for measuring an ultrasonic sound when a partial discharge of a partial discharge measurement object is generated; An A / D converter for converting an ultrasonic signal from the ultrasonic sensor into a digital signal; A ring buffer unit for sequentially arranging the converted digital signals in a ring type memory area; A signal processing unit for performing an FFT on data signals in each memory space of the ring buffer unit; A peak detector for extracting and storing a peak voltage and a frequency from the FFT-processed signal in the signal processor; A data post processor for maintaining the peak voltage and the frequency output from the peak detector at a maximum value for a predetermined time and outputting the peak voltage and frequency; The FFT-based partial discharge noise elimination signal processing apparatus according to the present invention comprises:

In one embodiment of the present invention, the output part of the data post processing part is further connected to a tone generator for generating and outputting an audible frequency at a peak voltage and a frequency, and a D / A converter for outputting a peak voltage and a frequency as an analog signal .

In addition, a speaker including a headphone is connected to the tone generator, and a computer and a smart electronic device capable of displaying an analog-converted signal are connected to the D / A converter.

In one embodiment of the present invention, the ring buffer unit is characterized in that a plurality of memory spaces are arranged in a ring-type structure and are sequentially connected.

According to another aspect of the present invention, there is provided an ultrasonic diagnostic apparatus comprising: an ultrasonic sensor for measuring an ultrasonic sound when a partial discharge is generated from a partial discharge measurement object; Converting the measured ultrasound signal into a digital signal; Filling the converted digital signal into a ring type memory space of the ring buffer unit in order to prepare for FFT conversion; Converting a digital signal filled in a plurality of memory spaces of the ring buffer unit to FFT in a signal processing unit; Determining whether a voltage and a frequency obtained by FFT-transforming the digital signal are a peak voltage and a frequency corresponding to a specific region required as an actual signal in the frequency domain of the ultrasonic signal; A peak voltage and a peak frequency judged as actual signals are extracted and stored in a peak detecting section; Maintaining the peak voltage and the frequency output from the peak detecting unit at a maximum value for a predetermined time and outputting the peak voltage and frequency; A partial discharge noise elimination signal processing method using an FFT is provided.

In another embodiment of the present invention, every time a plurality of memory spaces of the ring buffer unit are arranged in a ring-type structure and the converted digital signals are sequentially filled in each memory space, FFT conversion is repeatedly performed by the signal processing unit .

In another embodiment of the present invention, the step of determining the peak voltage and the frequency comprises: sequentially performing FFT transform on the data filled in the memoring space of the ring buffer unit, wherein the voltage value of the data frequency (f) Determining whether the peak value is greater than a threshold peak value; Determining a frequency (f) voltage value and a frequency of an FFT conversion target as a peak voltage and a peak frequency if the voltage value of the frequency is larger than the threshold peak value; Is repeatedly performed.

According to another embodiment of the present invention, the peak voltage and frequency outputted from the data post processor 24 are output to a speaker by generating an audible frequency, and a peak voltage and frequency outputted from the data post processor 24 are converted into a D / Converter 26 into an analog signal, and then displaying the analog signal on a corresponding display of the computer and the smart electronic device.

Through the above-mentioned means for solving the problems, the present invention provides the following effects.

According to the present invention, by selecting only a specific region necessary as an actual signal in a frequency domain of an ultrasonic signal from an ultrasonic sensor by using an FFT technique, it is possible to extract the noise of the ultrasonic signal and optimize the sensitivity of the ultrasonic signal have.

That is, by acquiring only a specific region (actual signal portion) excluding noise, noise, and the like in the frequency domain of the ultrasonic signal, it is possible to obtain a signal obtained from an actual sensor, thereby optimizing the sensitivity of the ultrasonic sensor.

Further, since the extracted signal can be converted into a voice and a visual signal in the next process and recognized by a person, the accuracy of the partial discharge measurement location can be improved.

1 is a configuration diagram for a conventional partial discharge measuring method using ultrasonic waves,
2 is a waveform diagram showing an ultrasonic signal waveform and a frequency-converted signal waveform from an ultrasonic sensor,
FIG. 3 is a block diagram illustrating a partial discharge noise cancellation signal processing apparatus using an FFT according to the present invention.
4 is a partial discharge noise elimination signal processing using an FFT according to the present invention, which is a flowchart showing an FFT signal processing algorithm,
5 is a conceptual diagram illustrating a ring buffer memory structure of a partial discharge noise cancellation signal processing apparatus using an FFT according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention focuses on a point where only a desired signal can be extracted by selecting only a specific region (for example, 39 kHz to 40 kHz region) in the frequency region of the ultrasonic signal (upper yellow and sky blue portions) have.

That is, since the signal inside the red square in FIG. 2 corresponds to the actual signal and the remainder corresponds to the noise, the present invention can be applied to a specific region (actual signal inside the red square) in the frequency domain of the ultrasonic signal using the FFT technique, Only a necessary signal can be extracted as a signal.

3, the partial discharge noise elimination signal processing apparatus using the FFT of the present invention includes an ultrasonic sensor 10 for measuring an ultrasonic wave for partial discharge measurement with respect to a partial discharge measurement object, An A / D converter 20 for converting an ultrasonic signal from the ultrasonic sensor 10 into a digital signal, a ring buffer unit 21 for sequentially arranging the converted digital signals in a ring type memory area, A signal processor 22 for performing FFT on signals in the respective memory areas of the ring buffer unit 21 and a peak detector 22 for extracting and storing peak voltages and frequencies from signals subjected to FFT processing in the signal processor 22, A peak detector 23 and a data post processor 24 for maintaining the peak voltage and frequency output from the peak detector 23 at a maximum value for a predetermined time.

At this time, the signal processing unit 22 is implemented as a firmware and sequentially performs FFT transform of the digital signal output from the ring buffer unit. For example, the signal processing unit 22 performs 1024 point conversion and FFT conversion at a cycle of 197 Hz do.

In addition, the data post processing unit 24 processes the peak voltage and the frequency to maintain the peak value for 150 msec for an output to the D / A converter 26, for example.

The tone generator 25 and the D / A converter 26 are connected to the output of the data post processor 24 to convert the peak voltage and the frequency of the signal into a sound and a value, A speaker including a headphone is connected to the tone generator 25 to listen to a signal of a desired area. The D / A converter 26 is connected to a computer and a smart electronic device, Signal values are displayed.

At this time, the tone generator 25 generates and outputs an audible frequency in a range of, for example, 100 Hz to 4 kHz when the peak voltage value is equal to or higher than a threshold value using a timer in the microcontroller.

Hereinafter, a partial discharge noise cancellation signal processing method based on the above-described signal processing apparatus of the present invention will be described.

In order to achieve the characteristics of the ultrasonic sensor which reacts only at a specific frequency for the partial discharge measurement on the partial discharge measurement object based on the signal processing apparatus of the present invention as described above, the existing filtering process for the ultrasonic signal is performed by real- And can be displayed in the next process in the form of voice and time signals.

To this end, the ultrasonic sensor senses the ultrasonic sound when a partial discharge such as a corona is generated from a partial discharge measurement object (power receiving equipment used in industry and power system substation, power device such as high voltage switchboard, etc.).

Then, the ultrasound signal is converted into a digital signal by the A / D converter 20, and the converted digital signal is input to the ring buffer unit 21.

That is, the converted digital signals are sequentially arranged in the ring type memory area of the ring buffer unit 21 for FFT conversion preparation.

Next, the signal processing unit 22 sequentially FFT-converts the digital signals output from the ring buffer unit 21.

Hereinafter, the function of the ring buffer unit will be described with reference to FIG. 5, which shows an example of the memory structure of the ring buffer unit.

The memory space 27 of the ring buffer unit 21 is arranged in the ring type structure from 0 to 7 as shown in FIG. 5 and sequentially connected to the empty memory space 27 of 0 to 7, (Converted digital signal) sequentially.

When data is filled in all the memory spaces 27 from 0 to 7, one FFT by the signal processing unit 22 is executed.

After that, put the data in 0 again and perform the FFT in order of 1,2,3,4,5,6,7,0, then put the data in 1, FFT is performed in order of 0, 1, and then data is inserted into 2, and FFT is repeated in order of 3, 4, 5, 6, 7, 0,

In this way, the ring buffer unit 21 functions to sequentially execute the FFT algorithm for each data after sequentially inserting the data along the memory space 27 connected in a ring structure, and uses a predetermined memory It is not necessary to create or delete a memory, and thus it can be usefully used for high-speed processing for FFT conversion.

Hereinafter, a process of FFT-converting the data stored in the memory space of the ring buffer unit in the signal processor will be described with reference to FIG.

First, the FFT conversion for the data frame (1024 points) filled in the memoring space 27 of the ring buffer unit 21 is sequentially performed. If the voltage value of the start frequency f is larger than the threshold peak value .

As a result of the determination, if the voltage value of the start frequency is larger than the threshold peak value, the voltage value of the start frequency (f) is determined as the peak voltage and the start frequency (f) is determined as the peak frequency.

The peak voltage and the peak frequency thus determined are extracted and stored in the peak detector 23 and become a specific region required as an actual signal in the frequency domain of the ultrasonic signal.

On the other hand, if the voltage value of the start frequency f is smaller than the threshold peak value, a process of determining whether the voltage value of the start frequency f is greater than a threshold peak value from the next frequency f + 1 to the end frequency is sequentially performed . When the peak value is larger than the threshold peak value, the peak voltage and the peak frequency are extracted and stored in the peak detector 23.

Next, the data post processor 24 maintains the peak voltage and the frequency at the maximum value within the time period of 150 msec for output to the D / A converter 26, for example.

The peak voltage and frequency output from the data post processing unit 24 are input to the tone generator 25 and then output through the speaker including the headphone by making an audible frequency in the range of 100 Hz to 4 kHz, The skilled artisan can clearly recognize the size and type of the partial discharge as well as the position where the partial discharge is generated by the operator skilled in the art.

The peak voltage and the frequency output from the data post processing unit 24 are converted into analog signals in the D / A converter 26, and then displayed on the corresponding displays of the computer and the smart electronic device. Only the peak data within a necessary frequency range (for example, 39 kHz to 41 kHz) in the frequency domain of the noise canceled signal, that is, the ultrasonic signal, can be seen. Therefore, the position and the size and type of the partial discharge You will know.

Thus, by extracting only the frequency domain signals from the real-time ultrasound signals from the real-time ultrasound signals and converting them into A / D using the FFT technique, the process proceeds to the next step to remove noise from the ultrasound signals and optimize the sensitivity of the signals And the extracted signal can be converted into a voice and a visual signal in the next process and can be easily recognized by a person, so that the accuracy of the partial discharge measurement location can be improved.

10: Ultrasonic sensor
11: Ultrasonic amplifier
12:
13: A / D converter
14:
20: A / D converter
21: Ring buffer section
22: Signal processor
23:
24: Data post processing unit
25: tone generator
26: D / A converter
27: Memory space

Claims (9)

An ultrasonic sensor 10 for measuring an ultrasonic sound when a partial discharge of a partial discharge measuring object is generated;
An A / D converter 20 for converting an ultrasonic signal from the ultrasonic sensor 10 into a digital signal;
A ring buffer unit 21 for sequentially arranging the converted digital signals in a ring type memory area;
A signal processing section (22) for performing FFT on the data signal in each memory space (27) of the ring buffer section (21);
A peak detector 23 for extracting and storing a peak voltage and a frequency from the FFT-processed signal in the signal processor 22;
A data post processor (24) for maintaining the peak voltage and frequency output from the peak detector (23) at a maximum value for a predetermined time and outputting the peak voltage and frequency;
Wherein the partial discharge noise elimination signal processing unit comprises an FFT unit.
The method according to claim 1,
A tone generator 24 for generating and outputting an audible frequency at a peak voltage and a frequency and a D / A converter 26 for outputting a peak voltage and a frequency as an analog signal are further connected to the output part of the data post processing part 24 Wherein the partial discharge noise elimination signal processing unit comprises an FFT.
The method of claim 2,
A speaker including a headphone is connected to the tone generator 24, and a computer and a smart electronic device capable of displaying an analog-converted signal are connected to the D / A converter 26. The partial discharge noise Removed signal processing device.
The method according to claim 1,
Wherein the ring buffer unit (21) is arranged such that a plurality of memory spaces (27) are arranged in a ring-type structure and are sequentially connected to each other.
Measuring an ultrasonic sound when the partial discharge is generated from the partial discharge measurement object by the ultrasonic sensor 10;
Converting the measured ultrasound signal into a digital signal;
Filling the converted digital signal into the ring type memory space 27 of the ring buffer unit 21 in order to prepare for FFT conversion;
Converting the digital signals filled in the plurality of memory spaces 27 of the ring buffer unit 21 into FFTs by the signal processing unit 22;
Determining whether a voltage and a frequency obtained by FFT-transforming the digital signal are a peak voltage and a frequency corresponding to a specific region required as an actual signal in the frequency domain of the ultrasonic signal;
A peak voltage and a peak frequency judged as actual signals are extracted and stored in the peak detecting section 23;
Maintaining the peak voltage and the frequency output from the peak detector (23) at a maximum value for a predetermined time and outputting the peak voltage and frequency;
Wherein the partial discharge noise elimination signal processing method comprises the steps of:
The method of claim 5,
The FFT conversion is repeatedly performed by the signal processing unit 22 every time the converted digital signals are sequentially filled in each memory space in a state that a plurality of memory spaces of the ring buffer unit 21 are arranged in a ring type structure (Partial Discharge Noise Reduction Signal Processing Method Using FFT.
The method of claim 5,
Wherein determining the peak voltage and frequency comprises:
A step of sequentially performing FFT transform on the data filled in the memoring space 27 of the ring buffer unit 21 and determining whether the voltage value of the data frequency f to be FFT-transformed is larger than a threshold peak value and;
Determining a frequency (f) voltage value and a frequency of an FFT conversion target as a peak voltage and a peak frequency if the voltage value of the frequency is larger than the threshold peak value;
Wherein the partial discharge noise elimination signal processing method comprises the steps of:
The method of claim 5,
And outputting the peak voltage and the frequency to be output to the loudspeaker after the step of outputting the peak voltage and the frequency outputted from the peak detector 23 at a maximum value for a predetermined time and outputting the peak voltage and frequency. A Partial Discharge Noise Reduction Signal Processing Method Using FFT.
The method of claim 5,
After the step of outputting the peak voltage and the frequency outputted from the peak detecting unit 23 at a maximum value for a predetermined time and then outputting, the peak voltage and the frequency to be outputted are converted from the D / A converter 26 into an analog signal, And displaying on a corresponding display of the smart electronic device. ≪ Desc / Clms Page number 19 >

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