JP4594646B2 - Damage detection method for partial discharge and damage detection apparatus for partial discharge - Google Patents

Description

  The present invention detects an elastic wave generated by acoustic emission caused by partial discharge in an electric device such as a transformer, a capacitor, and a generator, and detects a damage amount due to partial discharge based on the detected elastic wave The present invention relates to a discharge damage amount detection method and a partial discharge damage amount detection apparatus.

Substation equipment, particularly transformers, is a source of energy for production equipment, so accidents and failures are directly related to production outages and delays. Factors that cause transformer degradation can be broadly divided into electrical factors, thermal factors, environmental factors, mechanical factors, scientific factors, and others. Among these factors, the causes of failure are thermal factors and mechanical factors in particular, and the insulation capacity decreases due to changes in the physical properties of the insulator due to thermal factors and mechanical factors. Partial discharge occurs, greatly reducing the life of the transformer.
Partial discharge occurs when the local electric field strength exceeds the dielectric strength of the dielectric, causing local ionization and breakdown, depending on the intensity, light, heat, sound (elastic wave), radio interference Accompanying the emission of radio waves.

Conventionally, transformer soundness diagnosis has been performed mainly by a method of analyzing the gas in the oil of the insulating oil and a method of measuring the corona discharge amount with an ultrasonic wave.
Patent Document 1 discloses an electrical insulation coil that detects an acoustic emission (AE) wave caused by a partial discharge generated from an electrical insulation coil, and simultaneously measures the effective value voltage and the maximum amplitude value of the detected and amplified AE signal. An insulation characteristic measurement method is disclosed.
Japanese Patent Laid-Open No. 7-218480

In the conventional transformer health diagnosis method described above, it is difficult to accurately grasp abnormalities due to partial discharge of the transformer at an early stage, and furthermore, oil analysis requires large-scale analysis equipment. There is a problem that abnormality due to discharge cannot be detected.
The present invention has been made in view of the above-described circumstances. In the first and second inventions, it is possible to accurately grasp an abnormality caused by partial discharge at an early stage, and no large-scale equipment is required. An object of the present invention is to provide a partial discharge damage detection method capable of detecting an abnormality caused by partial discharge on-site without stopping the equipment.
In the third and fourth inventions, it is possible to accurately grasp an abnormality caused by partial discharge at an early stage, a portion that can detect an abnormality caused by partial discharge on-site without requiring large-scale equipment and stopping the equipment. It is an object of the present invention to provide a discharge damage detection device.

  The inventor of the present invention applies a positive voltage to the test piece 22 of carbon steel S45C and a negative voltage to the probe 23 by the high voltage generator 20 using a test apparatus as shown in the explanatory diagram of FIG. Each was applied to generate a partial discharge. A sensor 24 which is a piezoelectric element was attached to the test piece 22 to detect an elastic wave generated by acoustic emission caused by partial discharge, and displayed and recorded on a display recording device 25 having an oscilloscope. Further, the discharge charge amount was detected by the current detected by the ammeter 21 connected between the test piece 22 and the high voltage generator 20 and recorded in the display recording device 25.

As a result of generating partial discharge by changing the test conditions in various ways, the test piece 22 has a cross section as shown in the explanatory diagram of FIG. 5B, and has a depth L and a maximum diameter W that differ depending on the test conditions. Various damaged parts due to partial discharge were formed.
As shown in the waveform diagram of FIG. 6, the elastic wave signal detected and amplified by the sensor 24 has a maximum amplitude near the rising edge and continues for a certain period of time. The area of the elastic wave signal that lasts for a certain period of time represents the magnitude of the energy of the elastic wave due to acoustic emission. Further, it has been found that the frequency component of the elastic wave signal that has continued for a certain period falls within the range of 20 kHz to 1 MHz as shown in the characteristic diagram of FIG.

As a result, it was found that the discharge charge amount (pico coulomb) and the acoustic wave energy magnitude (in dB) by acoustic emission show the relationship shown in the characteristic diagram of FIG.
Further, it has been found that the maximum amplitude (in dB) of the elastic wave by acoustic emission and the damage depth of the damaged portion show a relationship as shown in the characteristic diagram of FIG.
Further, it has been found that the magnitude of energy of elastic waves by acoustic emission (in dB) and the damaged volume (cubic millimeter) of the damaged portion show a relationship as shown in the characteristic diagram of FIG. 9B.

The partial discharge damage amount detection method according to the first aspect of the present invention detects an elastic wave generated by acoustic emission resulting from partial discharge in an electrical device, and detects the damage amount due to the partial discharge based on the detected elastic wave. A method for detecting the amount of damage in partial discharge, wherein a predetermined frequency band component of the detected elastic wave is discriminated, the maximum amplitude of the discriminated frequency band component is detected, and the maximum amplitude obtained in advance and the surface of the damaged portion due to the partial discharge The depth of damage from the surface of the damaged portion due to partial discharge is detected based on the relationship with the damage depth from the surface and the detected maximum amplitude.

  The partial discharge damage amount detection method according to the second aspect of the present invention detects an elastic wave generated by acoustic emission caused by partial discharge in an electric device, and detects the damage amount due to the partial discharge based on the detected elastic wave. A method for detecting the amount of damage of partial discharge, which discriminates a predetermined frequency band component of the detected elastic wave, calculates an integrated value for a predetermined time of the discriminated frequency band component, and calculates the integral value obtained in advance and partial discharge Based on the relationship with the damaged volume of the damaged portion and the calculated integral value, the damaged volume of the damaged portion due to the partial discharge is detected.

According to a third aspect of the present invention, there is provided a partial discharge damage amount detection device comprising a sensor for detecting an elastic wave generated by acoustic emission resulting from a partial discharge in an electrical device, and the partial discharge based on the elastic wave detected by the sensor. A partial discharge damage amount detection device for detecting a damage amount caused by a sensor, wherein a means for discriminating a predetermined frequency band component of an elastic wave detected by the sensor, and a maximum amplitude of the frequency band component discriminated by the means are detected. Based on the detection means, the relationship between the maximum amplitude obtained in advance and the damage depth from the surface of the damaged portion caused by partial discharge, and the maximum amplitude detected by the detection means , the damage depth from the surface of the damaged portion caused by partial discharge is calculated. And means for detecting.

In the partial discharge damage detection method according to the first invention and the partial discharge damage detection device according to the third invention, the sensor detects an elastic wave generated by acoustic emission caused by the partial discharge in the electrical equipment. The amount of damage due to partial discharge is detected based on the elastic wave detected by the sensor. The discriminating means discriminates a predetermined frequency band component of the elastic wave detected by the sensor, and the detecting means detects the maximum amplitude of the discriminated frequency band component. Based on the relationship between the maximum amplitude obtained in advance and the damage depth from the surface of the damaged part due to partial discharge, and the maximum amplitude detected by the detection means, the means for detecting detects the damage depth from the surface of the damaged part due to partial discharge. To detect.

  According to a fourth aspect of the present invention, there is provided a partial discharge damage amount detection apparatus comprising a sensor for detecting an elastic wave generated by acoustic emission resulting from a partial discharge in an electric device, and the partial discharge based on the elastic wave detected by the sensor. A damage amount detection device for partial discharge that detects a damage amount caused by the above-mentioned method, wherein a means for discriminating a predetermined frequency band component of the elastic wave detected by the sensor, and an integration for a predetermined time of the frequency band component discriminated by the means A means for calculating a value, a relationship between an integral value obtained in advance and a damaged volume of a damaged portion caused by partial discharge, and a means for detecting a damaged volume of a damaged portion caused by partial discharge based on the integrated value calculated by the calculating means It is characterized by providing.

  In the partial discharge damage amount detection method according to the second aspect of the invention and the partial discharge damage amount detection device according to the fourth aspect of the invention, the sensor detects an elastic wave generated by acoustic emission resulting from the partial discharge in the electrical equipment. The amount of damage due to partial discharge is detected based on the elastic wave detected by the sensor. The discriminating means discriminates a predetermined frequency band component of the elastic wave detected by the sensor, and the calculating means calculates an integrated value for a predetermined time of the discriminated frequency band component. The detecting means detects the damaged volume of the damaged portion caused by the partial discharge based on the relationship between the integral value obtained in advance and the damaged volume of the damaged portion caused by the partial discharge, and the integrated value calculated by the calculating means.

  According to the partial discharge damage amount detection method according to the first and second inventions, it is possible to accurately grasp an abnormality due to partial discharge at an early stage, without requiring large-scale equipment and without stopping the equipment. In addition, it is possible to realize a partial discharge damage detection method that can detect abnormalities due to partial discharge in the field.

  According to the partial discharge damage amount detection apparatus according to the third and fourth inventions, it is possible to accurately grasp an abnormality due to partial discharge at an early stage, without requiring large-scale equipment and without stopping the equipment. In addition, it is possible to realize a partial discharge damage amount detection device that can detect abnormalities due to partial discharge in the field.

Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing the main configuration of a first embodiment of a partial discharge damage amount detection method and partial discharge damage amount detection apparatus according to the present invention. This partial discharge damage detection apparatus includes an AE sensor 1 that is a piezoelectric element, a preamplifier 2 that amplifies an elastic wave signal detected by the AE sensor 1, and a bandpass filter that discriminates a predetermined frequency band of the amplified elastic wave signal. 3 and a maximum amplitude detector 4 for detecting the maximum amplitude of the discriminated elastic wave signal in the frequency band are connected in this order.

The detected maximum amplitude is given to the damage amount detection unit 5. The damage amount detection unit 5 shows the relationship between the maximum amplitude of the elastic wave and the damage depth of the damaged part, as shown in FIG. 9A, which is obtained in advance in the same transformer as the transformer to be detected. A table 9 is built in, and the damage depth of the damaged portion due to the partial discharge is detected with reference to the table 9 based on the given maximum amplitude. The table 9 may be obtained by a partial discharge test as shown in FIG. 5 because there is no great difference if the test conditions are the same.
The detected damage depth is displayed on the display unit 6 and recorded in the recording unit 8.

less than. The operation of the partial discharge damage amount detection apparatus having such a configuration will be described.
The AE sensor 1 is attached to the outer surface of a transformer or the like to be detected, and detects an elastic wave generated by acoustic emission (AE) caused by partial discharge. The elastic wave signal detected by the AE sensor 1 is amplified by the preamplifier 2 and then the frequency components of 20 kHz to 1 MHz are discriminated by the band pass filter 3.
The maximum amplitude of the elastic wave signal of the frequency component discriminated by the bandpass filter 3 is detected by the maximum amplitude detector 4, and the detected maximum amplitude is given to the damage amount detector 5.

The damage amount detection unit 5 refers to the table 9 based on the given maximum amplitude, and determines the damage depth of the damaged portion due to partial discharge from the relationship between the maximum amplitude of the elastic wave indicated by the table 9 and the damage depth of the damaged portion. To detect.
The recording unit 8 records the damage depth detected by the damage amount detection unit 5. At the time of inspection, the user can display the damage depth recorded by the recording unit 8 so far on the display unit 8 and use it as data when evaluating the amount of damage due to partial discharge.

(Embodiment 2)
FIG. 2 is a block diagram showing a main configuration of a second embodiment of the partial discharge damage detection method and partial discharge damage detection apparatus according to the present invention. In this partial discharge damage amount detection apparatus, the AE sensor 1, the preamplifier 2, the band-pass filter 3, and the energy calculation unit 7 are connected in this order. The energy calculation unit 7 integrates the elastic wave signal in the frequency band discriminated by the band pass filter 3 for a predetermined time from the rise until it attenuates and substantially disappears, and calculates the energy value of the elastic wave by acoustic emission.

The calculated energy value (integral value) of the elastic wave is given to the damage amount detection unit 5a. The damage amount detection unit 5a obtains the relationship between the magnitude of the energy of the elastic wave and the damaged volume of the damaged part as shown in FIG. 9B, which is obtained in advance in a transformer similar to the transformer to be detected. The table 9a shown is built in, and the damaged volume of the damaged part due to the partial discharge is detected with reference to the table 9a by the energy value (integrated value) of the given elastic wave. The table 9a may be obtained by a partial discharge test as shown in FIG. 5 because there is no great difference if the test conditions are the same.
The detected damaged volume is displayed on the display unit 6 and recorded in the recording unit 8. Other configurations are the same as the main configuration of the partial discharge damage amount detection apparatus described in the first embodiment, and therefore, the same reference numerals are given to the same portions and the description thereof is omitted.

less than. The operation of the partial discharge damage amount detection apparatus having such a configuration will be described.
The AE sensor 1 is attached to the outer surface of a transformer or the like to be detected, and detects an elastic wave generated by acoustic emission (AE) caused by partial discharge. The elastic wave signal detected by the AE sensor 1 is amplified by the preamplifier 2 and then the frequency components of 20 kHz to 1 MHz are discriminated by the band pass filter 3.
The elastic wave signal of the frequency component discriminated by the band-pass filter 3 is integrated for a predetermined time by the energy calculating unit 7 to calculate the energy value of the elastic wave by acoustic emission. The calculated energy value (integral value) of the elastic wave is given to the damage amount detection unit 5a.

The damage amount detection unit 5a refers to the table 9a based on the given energy value (integrated value) of the elastic wave, and determines the relationship between the energy value (integrated value) of the elastic wave indicated by the table 9a and the damaged volume of the damaged portion. Detecting the damage volume of the damaged part due to partial discharge.
The recording unit 8 records the damage volume detected by the damage amount detection unit 5. At the time of inspection, the user can display the damaged volume recorded by the recording unit 8 so far on the display unit 8 and use it as data when evaluating the amount of damage due to partial discharge.

(Embodiment 3)
FIG. 3 is a block diagram showing the main configuration of Embodiment 3 of the partial discharge damage detection method and partial discharge damage detection device according to the present invention. As shown in FIG. 4, this partial discharge damage amount detection device is provided with one AE sensor 1 a to 1 f as a piezoelectric element on each of six surfaces of a transformer Tr that is a detection target. The AE sensors are used in pairs of (1a-1b), (1c-1d), and (1e-1f), and each pair is provided on the opposite surface.

  Each acoustic wave signal by acoustic emission (AE) caused by the partial discharge detected by the AE sensors 1a to 1f is amplified by the preamplifiers 2a to 2f, and the amplified acoustic wave signals are respectively bandpass filters 3a to 3a. A predetermined frequency band is discriminated in 3 f, and each elastic wave signal in the discriminated frequency band is given to the damage position calculation unit 10. The damage position calculation unit 10 calculates the spatial position of the damaged part due to the partial discharge based on each given elastic wave signal, gives it to the damage amount detection unit 5b, and causes the recording unit 8 to record it. The spatial position recorded in the recording unit can be displayed on the display unit 6. The damage amount detection unit 5b has a built-in table 9b indicating the relationship between the spatial position, the maximum amplitude of the elastic wave, and the damage depth of the damaged portion, and detects the damage depth of the damaged portion by this table 9b.

  On the other hand, the elastic wave signal in the frequency band discriminated by the band pass filter 3a is also supplied to the maximum amplitude detecting unit 4, and the maximum amplitude detecting unit 4 detects the maximum amplitude of the elastic wave signal in the discriminated frequency band. To the damage amount detector 5b. Other configurations are the same as the main configuration of the partial discharge damage amount detection apparatus described in the first embodiment, and therefore, the same reference numerals are given to the same portions and the description thereof is omitted.

less than. The operation of the partial discharge damage amount detection apparatus having such a configuration will be described.
The AE sensors 1a to 1f detect elastic waves generated by acoustic emission (AE) caused by partial discharge. The elastic wave signals detected by the AE sensors 1a to 1f are amplified by the preamplifiers 2a to 2f, respectively, and then frequency components of 20 kHz to 1 MHz are discriminated by the bandpass filters 3a to 3f, respectively.
The maximum amplitude detection unit 4 detects the maximum amplitude of the frequency component of the elastic wave signal discriminated by the bandpass filter 3a, and the detected maximum amplitude is given to the damage amount detection unit 5b.

  On the other hand, the frequency component elastic wave signals discriminated by the bandpass filters 3 a to 3 f are respectively supplied to the damage position calculation unit 10. The damage position calculation unit 10 calculates the difference in time when the rising edge of the elastic wave signal is detected in each pair (1a-1b) (1c-1d) (1e-1f) of the AE sensor, and the elastic wave is a medium (if it is a transformer). Calculate the position of the damaged part between the AE sensors (the position of the plane perpendicular to the straight line connecting the AE sensors and including the damaged part) from the speed of propagating the insulating oil) and each position of the AE sensor. To do. Next, the intersection of the three planes where each position is calculated for each pair is calculated as the spatial position of the damaged portion, and this spatial position is given to the damage amount detection unit 5b and recorded in the recording unit 8. If the AE sensors 1a to 1f are attached so that the three planes from which the respective positions are calculated are orthogonal to each other, the calculation becomes simple and easy to understand.

At the time of inspection, the user causes the display unit 8 to display the damage depth and the spatial position of the damaged part that have been recorded by the recording unit 8 so far, and evaluate the amount of damage due to partial discharge, and also during maintenance. Can be used as data. The other operations are the same as those of the partial discharge damage amount detection apparatus described in the first embodiment, and thus the description thereof is omitted.
In the third embodiment, the damage depth of the damaged portion is detected from the maximum amplitude of the elastic wave signal, but the energy value of the elastic wave signal is provided by providing an energy calculating unit instead of the maximum amplitude detecting unit. Needless to say, it is possible to adopt a configuration in which the damaged volume of the damaged portion is detected from the (integrated value).

It is a block diagram which shows the principal part structure of embodiment of the damage amount detection method and partial discharge damage detection apparatus which concern on this invention. It is a block diagram which shows the principal part structure of embodiment of the damage amount detection method and partial discharge damage detection apparatus which concern on this invention. It is a block diagram which shows the principal part structure of embodiment of the damage amount detection method and partial discharge damage detection apparatus which concern on this invention. It is explanatory drawing which shows the example of the attachment position to the transformer of six AE sensors. It is explanatory drawing which shows the example of the test apparatus of partial discharge typically. It is a wave form diagram which shows the example of the detection signal of the elastic wave which generate | occur | produced by the acoustic emission resulting from a partial discharge. It is a characteristic view which shows the example of the frequency component of the detection signal of the elastic wave generated by the acoustic emission resulting from a partial discharge. It is a characteristic view which shows the example of the relationship between the amount of discharge electric charges, and the magnitude | size of the energy of the elastic wave by acoustic emission. It is a characteristic view which shows the example of the relationship between the maximum amplitude and the energy of an elastic wave by acoustic emission, and the damage amount of a damaged part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a-1f AE sensor 2,2a-2f Preamplifier 3,3a-3f Band pass filter 4 Maximum amplitude detection part 5,5a, 5b Damage amount detection part 6 Display part 7 Energy calculation part 8 Recording part 9, 9a, 9b Table 20 High voltage generator 21 Ammeter 22 Test piece 23 Probe 24 Sensor 25 Display recording device

Claims (4)

A partial discharge damage amount detection method for detecting an elastic wave generated by acoustic emission caused by a partial discharge in an electrical device, and detecting a damage amount due to the partial discharge based on the detected elastic wave,
Discriminated the predetermined frequency band component of the detected elastic wave, detected the maximum amplitude of the discriminated frequency band component, detected the relationship between the maximum amplitude obtained in advance and the damage depth from the surface of the damaged part due to partial discharge, and detected A damage detection method for partial discharge, characterized by detecting a damage depth from the surface of a damaged portion caused by partial discharge based on the maximum amplitude. A partial discharge damage amount detection method for detecting an elastic wave generated by acoustic emission caused by a partial discharge in an electrical device, and detecting a damage amount due to the partial discharge based on the detected elastic wave,
Discriminate the predetermined frequency band components of the detected elastic wave, calculate the integrated value of the discriminated frequency band components for a predetermined time, and calculate the relationship between the calculated integrated value and the damaged volume of the damaged part due to partial discharge, and the calculation A damage amount detection method for partial discharge, wherein a damage volume of a damaged portion due to partial discharge is detected based on the integrated value obtained. A partial discharge damage detection device that includes a sensor that detects acoustic waves generated by acoustic emission caused by partial discharge in an electrical device, and that detects damage due to partial discharge based on the elastic waves detected by the sensor. There,
Means for discriminating a predetermined frequency band component of the elastic wave detected by the sensor; detection means for detecting the maximum amplitude of the frequency band component discriminated by the means; and the surface of the damaged portion caused by the maximum amplitude and partial discharge obtained in advance. relationship between the damage depth from, and based on said maximum amplitude detected by the detecting means, wherein to partial discharge damage amount detection by comprising means for detecting a damage depth from the surface of the damaged part by partial discharge apparatus. A partial discharge damage detection device that includes a sensor that detects acoustic waves generated by acoustic emission caused by partial discharge in an electrical device, and that detects damage due to partial discharge based on the elastic waves detected by the sensor. There,
A means for discriminating a predetermined frequency band component of the elastic wave detected by the sensor; a calculating means for calculating an integral value for a predetermined time of the frequency band component discriminated by the means; an integral value obtained in advance and a partial discharge A partial discharge damage amount detection apparatus, comprising: means for detecting a damage volume of a damaged portion due to partial discharge based on a relationship with a damaged volume of a damaged portion and an integral value calculated by the calculation means.

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