CN103344934A - Method and system for detecting and verifying partial discharge of power transformer through ultrasonic sensors - Google Patents

Abstract

The present invention provides a method and system for detecting and verifying a partial discharge ultrasonic sensor of a power transformer; the method includes steps A, performing longitudinal wave detection on the ultrasonic sensor; B, performing partial discharge on the power transformer with the ultrasonic sensor Detection; C. The ultrasonic sensor performs positioning detection on the partial discharge; the system includes an ultrasonic sensor longitudinal wave detection system, an ultrasonic sensor power transformer partial discharge detection system and an ultrasonic sensor power transformer partial discharge localization detection system. Compared with the prior art, the invention provides a method and system for detecting and verifying partial discharge ultrasonic sensors of power transformers, which realizes accurate and simple performance evaluation of different sensors for partial discharge and location detection of power transformers.

Description

Detection and verification method and system for partial discharge ultrasonic sensor of power transformer

technical field

The invention relates to a detection and verification method and system for an ultrasonic sensor, in particular to a detection and verification method and system for a partial discharge ultrasonic sensor of a power transformer.

Background technique

The power transformer is one of the important equipment in the power system, and its safe operation is of great significance; in the field operation, the partial discharge of the power transformer is one of the important reasons leading to the deterioration of the insulation of the power transformer. However, the accurate positioning of partial discharge sources inside large power transformers has always been a difficult problem in the field of high-voltage equipment insulation detection; various countries have carried out a lot of research work on the mechanism of partial discharge in transformers, and made great progress. Localization methods for partial discharge sources inside power transformers include:

Existing detection methods mainly use ultrasonic positioning method to detect partial discharge physical quantities to find out whether partial discharge has occurred inside the transformer; when partial discharge occurs inside the transformer, signals such as electromagnetic waves, discharge pulses, and ultrasonic waves will be generated, and ultrasonic waves will be generated in the transformer. Propagate in different media (oil paper, windings and partitions, etc.), and reach the ultrasonic sensor fixed on the wall of the transformer oil tank; use multiple ultrasonic sensors to measure the time delay of the signals measured by different sensors, and determine the position through the calculation of the positioning algorithm The location of the source. The ultrasonic signal generated by the partial discharge of power transformers is generally very weak. The higher the sensitivity of the ultrasonic sensor, the easier it is to detect the weak signal, and the signal-to-noise ratio will be improved accordingly. The ultrasonic signal is converted into a voltage signal.

The goal of transformer partial discharge ultrasonic sensor calibration is to obtain the response characteristics of the sensor, that is, to determine the transfer function of the sensor. Usually the exact expression of the transfer function is difficult to give, but in engineering applications, the response characteristics of the sensor will be drawn in the form of graphs, which is the common sensitivity curve. The use range of the sensor can be evaluated by the sensitivity curve of the sensor. Sensitivity curves are usually given as frequency versus output voltage under given conditions.

At present, there is no calibration standard for ultrasonic sensors for partial discharge localization of power transformers in China, so it is particularly important to provide a detection and calibration method and system for partial discharge ultrasonic sensors of power transformers.

Contents of the invention

In order to meet the needs of the prior art, the present invention provides a method for detecting and verifying a partial discharge ultrasonic sensor of a power transformer; the method includes the following steps:

A, carry out longitudinal wave detection to described ultrasonic sensor;

B. The ultrasonic sensor performs partial discharge detection on the power transformer;

C. The ultrasonic sensor performs location detection on the partial discharge.

Preferably, the ultrasonic sensor in the step A includes an ultrasonic sensor to be tested and a standard ultrasonic sensor; the transient recorder collects the ultrasonic sensor to be tested and the standard ultrasonic sensor respectively after measuring the waveform of the same longitudinal wave sound source The output voltage transient change value; the acoustic performance of the ultrasonic sensor to be tested is detected by the voltage transient change value;

Preferably, fast Fourier transform processing is performed on the voltage transient change value to obtain the complex-valued spectrum S(f _m ) of the standard ultrasonic sensor and the replicated spectrum U(f _m ) of the ultrasonic sensor to be tested; The amplitude and phase analysis of the value response D(f _m ) is used to verify the acoustic performance; the complex value response D(f _m ) of the ultrasonic sensor to be tested is calculated by formula (1):

$\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, S ₀ (f _m ) is the complex-valued response of the standard ultrasonic sensor, which is obtained from the first-level calibration results of the standard ultrasonic sensor; f _m is the frequency; m=0,1,2,...(n/2)-1 , n is the number of sampling points processed by the fast Fourier transform;

Preferably, the ultrasonic sensor in the step B includes the ultrasonic sensor to be tested and a standard ultrasonic sensor; the transient recorder respectively collects the measured ultrasonic sensor and the standard ultrasonic sensor to the same electrode partial discharge model The output voltage transient change value; verify the sensitivity of the ultrasonic sensor to be tested by the voltage transient change value; use an oscilloscope to perform partial discharge on the same electrode of the ultrasonic sensor to be tested and the standard ultrasonic sensor Output waveform verification after model measurement;

Preferably, fast Fourier transform processing is performed on the voltage transient change value to obtain the complex-valued spectrum S(f _m ) of the standard ultrasonic sensor and the replicated spectrum U(f _m ) of the ultrasonic sensor to be tested; The sensitivity is verified by magnitude and phase analysis of the value response D(f _m );

Preferably, the number of the ultrasonic sensors in the step C is N, and N is at least 2; the ultrasonic positioning monitoring system respectively monitors the positioning detection results of the ultrasonic sensors for the same electrode partial discharge model; the positioning detection The result is compared with the actual discharge position of the electrode partial discharge model to determine the sensitivity of the ultrasonic sensor; the actual discharge position is obtained by three-dimensional coordinate measurement;

Preferably, when the ultrasonic sensor is a UHF sensor, the number of the UHF sensors is M, and M is at least 2; the UHF positioning monitoring system separately monitors the positioning detection results of the same electrode partial discharge model by the UHF sensor; Comparing the location detection result with the actual discharge position of the electrode partial discharge model to determine the sensitivity of the UHF sensor; the actual discharge position is obtained through three-dimensional coordinate measurement.

In order to meet the needs of the prior art, the present invention further provides a detection and verification system for the partial discharge ultrasonic sensor of a power transformer; the detection and verification system includes an ultrasonic sensor longitudinal wave detection system, an ultrasonic sensor power transformer partial discharge detection system and an ultrasonic Sensor power transformer partial discharge location detection system;

The ultrasonic sensor longitudinal wave detection system includes ultrasonic sensors to be tested and standard ultrasonic sensors symmetrically arranged on both sides of the transformer oil tank; the ultrasonic source simulation device is arranged in the center of the transformer oil tank through the bottom bracket; The amplifier is connected with the oscilloscope; the ultrasonic sensor to be tested and the standard ultrasonic sensor are respectively connected with the computer through the transient recorder.

Preferably, the ultrasonic source simulating device is a glass capillary ultrasonic source simulating device; the glass capillary of the ultrasonic source simulating device is placed on the bottom bracket through a glass sheet; the diameter of the glass capillary is 0.2 mm; the loading screw vertically arranged above the glass capillary; the loading screw exerts pressure on the glass capillary through a glass rod;

After the loading screw exerts pressure on the glass capillary, the impact force when the glass capillary breaks is a step signal with a rise time of 0.1us; the value of the impact force passes through the piezoelectric ceramics of the loading screw and the Measured by an oscilloscope;

Preferably, the ultrasonic sensor power transformer partial discharge detection system includes the ultrasonic sensor to be tested and the standard ultrasonic sensor symmetrically arranged on both sides of the transformer oil tank; the electrode partial discharge model is arranged at any position of the transformer oil tank ; The two ends of the electrode partial discharge model are respectively connected to the high-voltage lead wire and ground of the non-partial discharge step-up transformer through a transformer bushing; the ultrasonic sensor to be measured and the standard ultrasonic sensor are respectively connected to the oscilloscope; The ultrasonic sensor to be tested and the standard ultrasonic sensor are respectively connected to the computer through the transient recorder;

Preferably, the electrode partial discharge model includes a needle-plate electrode model, a ball-plate electrode model, a suspension electrode model, a creeping electrode model, an air-gap electrode model, and a flat-plate electrode model; the electrode partial discharge models respectively realize needle-plate discharge in oil , Oil-paper insulation discharge, floating potential discharge in oil, surface discharge of insulating cardboard, air bubble discharge in oil and defect discharge of insulating cardboard;

Preferably, the ultrasonic sensor power transformer partial discharge localization detection system includes the electrode partial discharge model and the ultrasonic sensor to be tested arranged at any position inside the transformer oil tank; The monitoring system is connected; the number of the ultrasonic sensors to be tested is N, and N is at least 2;

The ultrasonic positioning monitoring system respectively monitors the positioning detection results of the ultrasonic sensor to be tested on the same electrode partial discharge model; compares the positioning detection results with the actual discharge position of the electrode partial discharge model to determine the The sensitivity of the ultrasonic sensor to be tested; the actual discharge position is obtained by three-dimensional coordinate measurement;

Preferably, when the ultrasonic sensor to be tested is a UHF sensor, the UHF sensor is connected to the UHF positioning monitoring system through a feeder; the number of the UHF sensors is M, and M is at least 2;

The UHF positioning monitoring system respectively monitors the positioning detection results of the same electrode partial discharge model by the UHF sensor; compares the positioning detection results with the actual discharge position of the electrode partial discharge model to judge the UHF sensor Sensitivity; the actual discharge position is obtained by three-dimensional coordinate measurement.

The beneficial effects of the present invention are:

1. In the technical solution of the present invention, an oscilloscope is used to respectively display the output voltage variation waveforms of the ultrasonic sensor to be tested and the standard ultrasonic sensor for the detection of the same longitudinal wave sound source waveform by the ultrasonic sensor when the longitudinal wave detection is performed on the ultrasonic sensor. Performance comparison and judgment are more intuitive and convenient;

2. In the technical solution of the present invention, when performing longitudinal wave detection on the ultrasonic sensor, the sensitivity or acoustic performance of the ultrasonic sensor to be tested can be verified by analyzing the amplitude and phase of the complex response D (f _m ) of the ultrasonic sensor to be tested. more precise;

3. In the technical solution of the present invention, an oscilloscope is used to respectively display the output voltage variation waveforms of the ultrasonic sensor to be tested and the standard ultrasonic sensor for the partial discharge model detection of the same motor when the ultrasonic sensor detects the partial discharge of the power transformer, and the sensitivity of the ultrasonic sensor to be tested is Comparison and judgment are more intuitive and convenient;

4. In the technical solution of the present invention, the ultrasonic source generated by the glass capillary ultrasonic source simulation device of the ultrasonic sensor longitudinal wave detection system has high repeatability and stable characteristics, which provides a guarantee for the acoustic performance verification of the ultrasonic sensor;

5. In the technical solution of the present invention, when the ultrasonic sensor detects the partial discharge of the power transformer, the sensitivity calibration of the ultrasonic sensor to be tested is made more accurate by analyzing the amplitude and phase of the complex value response D (f _m ) of the ultrasonic sensor to be tested ;

6. In the technical solution of the present invention, the electrode partial discharge model of the ultrasonic sensor power transformer partial discharge detection system can simulate needle plate discharge in oil, oil-paper insulation discharge, suspension potential discharge in oil, surface discharge of insulating cardboard, bubble discharge in oil and insulation Cardboard defect discharge provides an accurate test platform for comprehensive calibration of ultrasonic sensors;

7. In the technical solution of the present invention, the ultrasonic sensor power transformer partial discharge localization detection system can realize the performance verification detection between multiple different ultrasonic sensors; at the same time, it can also realize the performance verification between multiple different UHF sensors detection.

8. The method and system for detecting and verifying partial discharge ultrasonic sensors of power transformers provided by the present invention provides a performance comparison platform for sensors produced by different manufacturers; it realizes the accurate detection and positioning of partial discharge of power transformers by different sensors, Easy performance evaluation.

9. The detection and verification method and system of a partial discharge ultrasonic sensor of a power transformer provided by the present invention is aimed at the fact that there is no relevant standard for the performance detection and evaluation of the partial discharge ultrasonic sensor of a power transformer in China at present, and the formulation of industry standards in the future It has reference value.

10. The method and system for detecting and verifying partial discharge ultrasonic sensors of power transformers provided by the present invention are suitable for other occasions where ultrasonic sensors are used to detect partial discharges, such as partial discharge ultrasonic detection of gas-insulated combined electrical appliances (GIS), partial discharge of reactors, etc. Ultrasound testing, etc.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Figure 1 is: a structural diagram of a detection and verification system for a partial discharge ultrasonic sensor of a power transformer provided by the present invention;

Fig. 2 is: the structural diagram of the ultrasonic sensor longitudinal wave detection system in the embodiment of the present invention;

Fig. 3 is: the structural diagram of the ultrasonic source simulation device in the embodiment of the present invention;

Fig. 4 is: a structural diagram of a partial discharge detection system of an ultrasonic sensor power transformer in an embodiment of the present invention;

Fig. 5 is: the structural diagram of the electrode partial discharge model in the embodiment of the present invention;

Fig. 6 is a structural diagram of a partial discharge detection system of an ultrasonic sensor power transformer in an embodiment of the present invention;

Among them, 1: Oil tank; 2: Transformer oil; 3: Ultrasonic sensor to be tested; 4: Standard ultrasonic sensor; 5: Glass capillary ultrasonic source simulation device; 51: Loading screw; 52: Piezoelectric ceramics; 53: Glass rod; 54 : glass plate; 55: glass capillary; 6: preamplifier; 7: oscilloscope; 8: transient recorder; 9: computer; 10: electrode partial discharge model; 101: needle-plate electrode model; 102: ball-plate electrode model ;103: suspension electrode model; 104: surface electrode model; 105: air gap electrode model; 106: plate electrode model; 11: transformer bushing 1; 12: transformer bushing 2; 13: high voltage electrode; 14: insulating cardboard; 15: ground electrode; 16: suspended metal; 17: internal defect of insulating cardboard; 18: parallel gap of insulating cardboard; 19: ultrasonic sensor; 20: ultrasonic sensor positioning monitoring system; 21: UHF sensor; 22: UHF positioning monitoring system.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

The steps of a method for detecting and verifying a partial discharge ultrasonic sensor of a power transformer provided by the present invention are as follows: A. performing longitudinal wave detection on the ultrasonic sensor; B. performing partial discharge detection on the power transformer by the ultrasonic sensor; C. The ultrasonic sensor performs positioning detection on the partial discharge;

I: (1) When performing longitudinal wave detection on the ultrasonic sensor, the transient recorder separately collects the voltage transient change value output by the ultrasonic sensor to be tested and the standard ultrasonic sensor after measuring the waveform of the same longitudinal wave sound source;

(2) Perform fast Fourier transform processing on the voltage transient change value to obtain the amplitude spectrum diagram and phase spectrum diagram of the sensor to be tested and the amplitude spectrum diagram and phase spectrum diagram of the standard sensor respectively; Data analysis of the spectrogram to compare and judge the sensitivity or acoustic performance of the ultrasonic sensor to be tested;

The complex-valued spectrum S(f _m ) of the standard ultrasonic sensor and the replicated spectrum U(f _m ) of the ultrasonic sensor to be tested are:

$\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="i"\; filenames="HDA00003509168700012.png"\; state="\{\{state\}\}">i</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;mj</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

$\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\mathrm{<span\; class="notranslate">\; exp</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="i"\; filenames="HDA00003509168700012.png"\; state="\{\{state\}\}">i</figure-callout></span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;mj</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ;</span>$

Wherein, n is the number of sampling points processed by the fast Fourier transform;

j=0, 1, 2..., (n/2)-1; m=0, 1, 2..., (n/2)-1;

s _j is the jth sampling point in the standard ultrasonic sensor channel;

u _j is the jth sampling point in the channel of the ultrasonic sensor to be tested;

f _m is the mth frequency, in MHz;

The complex-valued response D(f _m ) of the ultrasonic sensor to be tested is:

Amplitude r _m = |D(f _m )|, phase of complex-valued response D(f _m ) of ultrasonic sensor to be tested

Among them, S ₀ (f _m ) is the complex-valued response of the standard ultrasonic sensor, which is obtained from the primary calibration result of the standard ultrasonic sensor;

I _z and R _z respectively represent the imaginary part and the real part of the complex number z;

The calibration amplitude W _m is usually expressed in dB as: W _m = 20log ₁₀ (r _m );

(3) By comparing and analyzing the amplitude and phase of the ultrasonic sensor to be tested and the standard ultrasonic sensor, the sensitivity or acoustic performance of the ultrasonic sensor to be tested can be accurately verified.

II: (1) When the ultrasonic sensor detects the partial discharge of the power transformer, the transient recorder respectively collects the voltage transient change value output by the ultrasonic sensor to be tested and the standard ultrasonic sensor after measuring the partial discharge model of the same electrode; through The voltage transient change value checks the sensitivity of the ultrasonic sensor to be tested; the output waveform after the measurement of the same electrode partial discharge model by the ultrasonic sensor to be tested and the standard ultrasonic sensor is checked by an oscilloscope;

和校准幅值W_m＝20log₁₀(r_m)的计算方法与对超声传感器进行纵波检测的方法相同；(2) Perform fast Fourier transform processing on the voltage transient change value to obtain the amplitude spectrum diagram and phase spectrum diagram of the sensor to be tested and the amplitude spectrum diagram and phase spectrum diagram of the standard sensor respectively; Spectrum diagrams are used for data analysis to compare and judge the sensitivity or acoustic performance of the ultrasonic sensor to be tested; the complex-valued spectrum S (f _m ) of the standard ultrasonic sensor, the replicated spectrum U (f _m ) of the ultrasonic sensor to be tested, and the complex-valued response of the ultrasonic sensor to be tested D(f _m ), amplitude r _m of D(f _m ) = |D(f _m )|, phase of D(f _m )

and the calculation method of the calibration amplitude W _m =20log ₁₀ (r _m ) is the same as the method for the longitudinal wave detection of the ultrasonic sensor;

(3) By comparing and analyzing the amplitude and phase of the ultrasonic sensor to be tested and the standard ultrasonic sensor, the sensitivity acoustics of the partial discharge detection of the power transformer of the ultrasonic sensor to be tested can be accurately verified.

III: When the ultrasonic sensor performs positioning detection on the partial discharge, the number of ultrasonic sensors is N, and N is at least 2; the ultrasonic positioning monitoring system separately monitors the positioning detection results of the ultrasonic sensors on the same electrode partial discharge model; the positioning detection results Compare with the actual discharge position of the electrode partial discharge model to judge the sensitivity of the ultrasonic sensor to be tested; the actual discharge position is obtained by three-dimensional coordinate measurement;

When the above-mentioned ultrasonic sensors are replaced by UHF sensors, the number of UHF sensors is M, and M is at least 2; the UHF positioning monitoring system monitors the positioning detection results of the same electrode partial discharge model by the UHF sensors respectively; the positioning detection results are compared with the electrode partial discharge model The actual discharge position is compared to judge the sensitivity of the ultrasonic sensor to be tested; the actual discharge position is obtained by three-dimensional coordinate measurement.

A power transformer partial discharge ultrasonic sensor detection and verification system provided by the present invention is shown in Figure 1. The detection and verification system includes an ultrasonic sensor longitudinal wave detection system, an ultrasonic sensor power transformer partial discharge detection system and an ultrasonic sensor power transformer local Discharge location detection system;

Fig. 2 shows the structural diagram of the ultrasonic sensor longitudinal wave detection system in the present embodiment; the ultrasonic sensor 3 to be tested and the standard ultrasonic sensor 4 are symmetrically arranged on both sides of the transformer oil tank 1; the glass capillary ultrasonic source simulation device 5 is arranged on the bottom bracket The center of the transformer oil tank 1; the glass capillary ultrasonic source simulation device 5 is connected to the oscilloscope 7 through the preamplifier 6; the ultrasonic sensor 3 to be tested and the standard ultrasonic sensor 4 are connected to the computer 9 through the transient recorder 8 respectively;

Fig. 3 shows the structural diagram of the ultrasonic source simulation device in the present embodiment; the ultrasonic source simulation device is a glass capillary ultrasonic source simulation device; the glass capillary 55 of the ultrasonic source simulation device is placed on the bottom support by a glass sheet 54; the glass capillary The diameter of 55 is 0.2mm; Loading screw 51 is vertically arranged above the glass capillary; Loading screw 51 applies pressure to glass capillary 55 through glass rod 53; After loading screw 51 applies pressure to glass capillary 55, the impact force when glass capillary 55 breaks is A step signal with a rise time of 0.1us; the value of the impact force is measured by loading the piezoelectric ceramic 52 (piezoelectric ceramic transducer, PZT) of the screw 51 and the oscilloscope 7;

Fig. 4 shows the structural diagram of the ultrasonic sensor power transformer partial discharge detection system in this embodiment; the ultrasonic sensor 3 to be tested and the standard ultrasonic sensor 4 are arranged symmetrically on both sides of the transformer oil tank 1; the electrode partial discharge model 10 is arranged on the transformer oil tank 1 Any position in the interior; one end of the electrode partial discharge model 10 is connected to the high-voltage lead wire of the non-partial discharge step-up transformer through the transformer bushing 1, and the other end is grounded through the transformer bushing 2; the ultrasonic sensor 3 to be tested and the standard ultrasonic sensor 4 are respectively connected to the The oscilloscope 7 is connected; the ultrasonic sensor 3 to be tested and the standard ultrasonic sensor 4 are respectively connected with the computer 9 through the transient recorder 8;

Fig. 5 shows the structural diagram of the electrode partial discharge model in the embodiment of the present invention; the electrode partial discharge model includes a pin plate electrode model, a ball plate electrode model, a suspension electrode model, a creeping electrode model, an air gap electrode model and a plate electrode model; The electrode partial discharge model realizes needle-plate discharge in oil, oil-paper insulation discharge, floating potential discharge in oil, surface discharge of insulating cardboard, air bubble discharge in oil and defect discharge of insulating cardboard;

Fig. 6 shows the structural diagram of the partial discharge localization detection system of the ultrasonic sensor power transformer in the embodiment of the present invention; Connect with the ultrasonic positioning monitoring system 20 through the feeder; the ultrasonic positioning monitoring system 20 monitors the localization detection results of the partial discharge of the same needle plate electrode model 101 by the ultrasonic sensor 19 respectively; Compare and judge the sensitivity of the ultrasonic sensor 19 one by one; wherein the actual discharge position is obtained by three-dimensional coordinate measurement;

When the ultrasonic sensor is replaced with a UHF sensor 21, the UHF sensor 21 is a plurality of UHF sensors from different manufacturers; the UHF sensor 21 is connected to the UHF positioning monitoring system 22 through a feeder; the UHF positioning monitoring system 22 monitors the UHF sensor 21 to the same The positioning detection result of the partial discharge of the needle plate electrode model 101; the positioning detection result is compared with the actual discharge position of the partial discharge of the needle plate electrode model, and the sensitivity of the UHF sensor 21 is judged one by one; wherein the actual discharge position is obtained by three-dimensional coordinate measurement .

Finally, it should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Claims (13)

1. a method for detecting and verifying a power transformer partial discharge ultrasonic sensor, is characterized in that, said method comprises the steps: A, carry out longitudinal wave detection to described ultrasonic sensor; B. The ultrasonic sensor performs partial discharge detection on the power transformer; C. The ultrasonic sensor performs location detection on the partial discharge. 2. the method for detecting and verifying of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 1, is characterized in that, described ultrasonic sensor in the described step A comprises ultrasonic sensor to be tested and standard ultrasonic sensor; Transient record The instrument collects the voltage transient change value output by the ultrasonic sensor to be tested and the standard ultrasonic sensor after measuring the waveform of the same longitudinal wave sound source; the acoustic performance of the ultrasonic sensor to be tested is detected by the voltage transient change value . 3. the method for detecting and verifying of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 2, it is characterized in that, carry out fast Fourier transform processing to described voltage transient change value, obtain standard ultrasonic sensor complex value spectrum S(f _m ) and the reproduction spectrum U(f _m ) of the ultrasonic sensor to be tested; the acoustic performance is verified by analyzing the amplitude and phase of the complex-valued response D(f _m ) of the ultrasonic sensor to be tested; The complex-valued response D (f _m ) of the ultrasonic sensor is calculated by formula (1): $\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ Among them, S ₀ (f _m ) is the complex-valued response of the standard ultrasonic sensor, which is obtained from the first-level calibration results of the standard ultrasonic sensor; f _m is the frequency; m=0,1,2,...(n/2)-1 , n is the number of sampling points processed by the fast Fourier transform. 4. the detection verification method of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 1, is characterized in that, described ultrasonic sensor in the described step B comprises ultrasonic sensor to be tested and standard ultrasonic sensor; Transient record The instrument collects the voltage transient change value output by the ultrasonic sensor to be tested and the standard ultrasonic sensor after measuring the same electrode partial discharge model; the sensitivity of the ultrasonic sensor to be tested is verified by the voltage transient change value and verifying the output waveforms of the same electrode partial discharge model measured by the ultrasonic sensor to be tested and the standard ultrasonic sensor by an oscilloscope. 5. the method for detecting and verifying of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 4, it is characterized in that, carry out fast Fourier transform processing to described voltage transient change value, obtain standard ultrasonic sensor complex value spectrum S(f _m ) and the reproduced spectrum U(f _m ) of the ultrasonic sensor under test; the sensitivity is verified by the amplitude and phase analysis of the complex-valued response D(f _m ) of the ultrasonic sensor under test. 6. The detection verification method of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 1, is characterized in that, the number of the described ultrasonic sensor in the described step C is N, and N is at least 2; The system respectively monitors the positioning detection results of the ultrasonic sensor on the same electrode partial discharge model; compares the positioning detection results with the actual discharge position of the electrode partial discharge model to determine the sensitivity of the ultrasonic sensor; the actual discharge The position is obtained by three-dimensional coordinate measurement. 7. the method for detecting and verifying of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 6, is characterized in that, when described ultrasonic sensor is UHF sensor, the number of described UHF sensor is M, and M is at least 2; The UHF positioning monitoring system respectively monitors the positioning detection results of the same described electrode partial discharge model by the UHF sensor; compares the positioning detection results with the actual discharge position of the electrode partial discharge model to determine the sensitivity of the UHF sensor ; The actual discharge position is obtained by three-dimensional coordinate measurement. 8. A detection and verification system for a partial discharge ultrasonic sensor of a power transformer, characterized in that the detection and verification system includes an ultrasonic sensor longitudinal wave detection system, an ultrasonic sensor power transformer partial discharge detection system and an ultrasonic sensor power transformer partial discharge location detection system; The ultrasonic sensor longitudinal wave detection system includes ultrasonic sensors to be tested and standard ultrasonic sensors symmetrically arranged on both sides of the transformer oil tank; the ultrasonic source simulation device is arranged in the center of the transformer oil tank through the bottom bracket; The amplifier is connected with the oscilloscope; the ultrasonic sensor to be tested and the standard ultrasonic sensor are respectively connected with the computer through the transient recorder. 9. The detection verification system of a kind of power transformer partial discharge ultrasonic sensor as claimed in claim 8, is characterized in that, described ultrasonic source simulation device is glass capillary ultrasonic source simulation device; The glass capillary of described ultrasonic source simulation device The glass sheet is placed on the bottom support; the diameter of the glass capillary is 0.2 mm; the loading screw is vertically arranged above the glass capillary; the loading screw applies pressure to the glass capillary through a glass rod; After the loading screw exerts pressure on the glass capillary, the impact force when the glass capillary breaks is a step signal with a rise time of 0.1us; the value of the impact force passes through the piezoelectric ceramics of the loading screw and the Oscilloscope measured. 10. The detection and verification system of a partial discharge ultrasonic sensor of a power transformer as claimed in claim 8, wherein the partial discharge detection system of the ultrasonic sensor power transformer includes the two symmetrically arranged on both sides of the transformer oil tank. The ultrasonic sensor to be tested and the standard ultrasonic sensor; the electrode partial discharge model is arranged at any position of the transformer oil tank; the two ends of the electrode partial discharge model are respectively connected to the high-voltage lead wire and the non-partial discharge step-up transformer through the transformer bushing The ultrasonic sensor to be tested and the standard ultrasonic sensor are respectively connected to the oscilloscope; the ultrasonic sensor to be tested and the standard ultrasonic sensor are respectively connected to the computer through the transient recorder. 11. The detection and verification system of a partial discharge ultrasonic sensor of a power transformer as claimed in claim 10, wherein the electrode partial discharge model includes a pin plate electrode model, a ball plate electrode model, a suspended electrode model, and a creeping electrode model. Model, air-gap electrode model and plate electrode model; the electrode partial discharge model realizes needle-plate discharge in oil, oil-paper insulation discharge, suspension potential discharge in oil, surface discharge of insulating cardboard, bubble discharge in oil and defect discharge of insulating cardboard. 12. The detection and verification system of a partial discharge ultrasonic sensor of a power transformer as claimed in claim 8 or 10, wherein the partial discharge detection system of the ultrasonic sensor power transformer includes a device installed at any position inside the transformer oil tank The electrode partial discharge model and the ultrasonic sensor to be tested; the ultrasonic sensor to be tested is connected to the ultrasonic positioning monitoring system through a feeder; the number of the ultrasonic sensors to be tested is N, and N is at least 2; The ultrasonic positioning monitoring system respectively monitors the positioning detection results of the ultrasonic sensor to be tested on the same electrode partial discharge model; compares the positioning detection results with the actual discharge position of the electrode partial discharge model to determine the The sensitivity of the ultrasonic sensor to be tested; the actual discharge position is obtained by three-dimensional coordinate measurement. 13. The detection and verification system of a partial discharge ultrasonic sensor of a power transformer as claimed in claim 12, wherein when the ultrasonic sensor to be tested is a UHF sensor, the UHF sensor is connected to the UHF positioning monitoring system through a feeder ; The number of UHF sensors is M, and M is at least 2; The UHF positioning monitoring system respectively monitors the positioning detection results of the same electrode partial discharge model by the UHF sensor; compares the positioning detection results with the actual discharge position of the electrode partial discharge model to judge the UHF sensor Sensitivity; the actual discharge position is obtained by three-dimensional coordinate measurement.

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