CN112858845A - Partial discharge diagnosis method for gas insulated switchgear - Google Patents
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Abstract
The invention relates to a partial discharge diagnosis method for a gas insulated switchgear, which is based on an ultrasonic technology, detects a large amount of collected data on site, diagnoses and analyzes GIS abnormity, summarizes time domain and phase distribution characteristics of an ultrasonic signal of typical GIS partial discharge, and analyzes the difference of a partial discharge signal and a common interference signal in the time domain characteristics and the frequency domain distribution. The method can be conveniently implemented in GIS on-site partial discharge detection by utilizing an acoustoelectric combined positioning method, an ultrasonic time delay positioning method and an ultrasonic wavelet time-frequency positioning method, and the result shows that the method has high precision and accuracy of defect positioning, so that the method can be used for guiding monitoring diagnosis and daily maintenance and management of the GIS equipment of the hydropower station, avoiding equipment faults such as corrosion of insulating media and the like caused by corresponding physical phenomena such as electricity, light, chemistry and the like generated by partial discharge, improving the on-site application level of GIS ultrasonic partial discharge detection and ensuring safe and stable operation of the power station equipment.
Description
Technical Field
The invention relates to a partial discharge diagnosis method for a gas insulated switchgear, in particular to a partial discharge diagnosis method for a gas insulated switchgear based on ultrasonic diagnosis.
Background
Gas Insulated Switchgear (GIS) has the advantages of compact structure, reliable operation, small operation and maintenance workload, etc., is widely used in power plants, substations and switchyards, the number of installation intervals is continuously increased, and the GIS becomes mainstream switchgear in power systems of 110kV and above. Although GIS main loop equipment is sealed in the grounding metal shell, the running reliability is high, and the overhaul period is long, the existing operation and maintenance experience shows that the equipment defects and the fault occurrence rate still increase year by year along with the running time, and hidden dangers are brought to the safe running of the GIS and even the power grid.
According to the statistics of GIS defects and faults, the proportion of insulation defects and faults caused by the insulation defects exceeds 50%, wherein the higher the GIS voltage level is, the greater the threat of the insulation defects to the safe operation of equipment is. Insulation defects of the GIS and the development thereof often cause internal partial discharge. The partial discharge can generate corresponding physical phenomena such as electricity, light, chemistry and the like, further deterioration of insulation is caused by corrosion of an insulating medium, and finally equipment failure is caused to influence safe operation of a power system. Partial discharges can lead to a continuous drop in the level of insulation within the device and also be a sign of degradation of the insulation of the device. The GIS partial discharge is subjected to live detection and defect positioning, so that the internal defects of the equipment can be timely found and eliminated, and the safe and reliable operation of the power equipment and even a power system is guaranteed; therefore, the partial discharge detection of the GIS equipment is very important.
A plurality of physical phenomena excited by the partial discharge in the equipment can be used as characteristic quantities for GIS partial discharge detection and diagnosis. The ultrasonic detection method is characterized in that a sensor is tightly attached to the outer surface of a GIS metal shell, and whether partial discharge exists in the equipment or not is judged according to a detection signal of the sensor. Compared with the ultrahigh frequency detection method, the ultrasonic method is not influenced by factors such as position, structure and material, can acquire signals at each position of the GIS, and has been widely applied on site after years of laboratory research. However, different from laboratory research, there are many interference factors for GIS field ultrasonic partial discharge detection, including mechanical vibration, external corona, etc., and it is difficult to accurately diagnose whether there is an insulation defect inside the GIS only by comparing the detected waveform with a typical map, which may cause the defect to be missed or misjudged, and greatly affect the field application effect of the GIS ultrasonic partial discharge detection method.
If a GIS equipment partial discharge diagnosis mode and method with low cost, strong operability, rapidness and more accuracy can be provided, the problems can be solved, and the GIS equipment partial discharge diagnosis and positioning work can be rapidly, conveniently and more accurately realized.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides the method for diagnosing the partial discharge of the gas insulated switchgear based on ultrasonic diagnosis, which is applied to on-site detection and diagnosis, is convenient and reasonable, has more accurate positioning, short detection period, low manufacturing cost and strong operability.
The technical scheme adopted by the invention for solving the problems is as follows: the partial discharge diagnosis method of the gas insulated switchgear is characterized by comprising the following steps: the method comprises the following specific steps:
s1: determining GIS equipment of a tested hydropower station, and checking whether ultrasonic partial discharge detection and positioning system equipment and a sensing device normally operate or not;
s2: collecting partial discharge signals of the GIS equipment by using an ultrasonic partial discharge detection and positioning system; comparing and analyzing the acquired detection signals with background noise signals and typical ultrasonic partial discharge signals, selecting abnormal detection signals, screening, processing and analyzing data, and preliminarily determining whether partial discharge and partial discharge types exist;
s3: carrying out frequency spectrum analysis on the original ultrasonic signals, eliminating signals such as mechanical vibration or external corona and the like, and if the frequency spectrum analysis result is similar to the frequency spectrum distribution of typical ultrasonic partial discharge signals, diagnosing by using a positioning method;
s4: and finally, comprehensive positioning is selected, various external interferences are further eliminated, and the discharge defect is accurately positioned, so that correct diagnosis of GIS partial discharge is realized, and related suggestions are provided for operation and maintenance of GIS equipment according to the diagnosis result.
Preferably, in step S1 of the present invention: the ultrasonic partial discharge detection and positioning system is a system for detecting GIS partial discharge, and the detection of whether equipment and sensing devices of the ultrasonic partial discharge detection and positioning system operate normally comprises the steps of checking whether each sensor of the ultrasonic partial discharge detection and positioning system fails or not and judging whether the detection precision reaches the standard or not; the sensor performs partial discharge diagnosis.
Preferably, in step S2 of the present invention: the data screening, processing and analyzing are data elimination, comparison, processing and analysis;
preferably, in step S2 of the present invention: the data processing and analysis comprises elimination of interference caused by noise, comparison of detected data with typical ultrasonic partial discharge signals, and further positioning diagnosis when frequency spectrums are similar.
Preferably, in step S2 of the present invention: the data processing and analysis is to perfect a GIS ultrasonic partial discharge signal analysis method by comparing ultrasonic signal characteristics of point discharge, suspension potential discharge, insulation internal discharge and insulation surface discharge and combining means such as frequency spectrum analysis.
Preferably, oscillation pulses of insulation air gap discharge and creeping discharge in the GIS can appear in positive and negative half cycles of a power frequency period, and the GIS has very obvious signal identification on uniform period, large amplitude, long oscillation time of a single pulse, very obvious frequency correlation of 100Hz and very obvious phase aggregation; in addition, the point discharge of which the oscillation pulse usually only appears in a certain power frequency half cycle and the polarity is very obvious is identified.
Preferably, in step S3 of the present invention: the positioning method is based on abnormal signal positioning of an ultrasonic principle and analyzes time domain characteristics and spectrum characteristics of detection signals.
Preferably, the diagnostic method of the present invention, the ultrasonic partial discharge detection and positioning system used for the detection channel, comprises a four-channel high sampling rate oscilloscope, an ultrasonic sensor corresponding to each channel, and a preposed signal amplifier,
preferably, the sampling rate of the oscilloscope is 5GS/s, and the analog bandwidth is 1 GHz; the frequency response effective detection frequency band is 10-200kHz, the resonance frequency is 30kHz, and the maximum detection sensitivity exceeds 80 dB; the preamplifier matched with the sensor has very good environmental noise suppression capability and linear amplification level in a differential amplification mode, and the amplification factor is adjustable in three stages of 20-60 dB.
Preferably, in step S4 of the present invention: the comprehensive positioning comprises an acoustic-electric combined positioning method, an ultrasonic time delay positioning method and an ultrasonic wavelet time-frequency positioning method.
Compared with the prior art, the invention has the following advantages and effects: (1) the method for diagnosing the partial discharge of the Gas Insulated Switchgear (GIS) solves the problem of limitation caused by factors such as position, structure and material, and avoids the defects, omission or misjudgment caused by numerous interference factors. The convenience, the rapidity and the operability of the wind turbine generator power curve test are improved; (2) the test rapidity is greatly improved, and meanwhile, the positioning precision and the test accuracy are greatly improved; (3) the maintenance cost of the power plant is reduced, and the condition maintenance is facilitated; (4) technical guidance is provided for safe and healthy operation of the GIS, and the occurrence frequency of faults is reduced.
Drawings
FIG. 1 is a schematic flow chart of an embodiment of the present invention.
Fig. 2 shows the measurement points of the sensor for detecting partial discharge of the abnormal voltage transformer (PT) according to the embodiment of the present invention.
FIG. 3 shows ultrasonic and UHF signals triggered by internal defects of a Potential Transformer (PT) according to an embodiment of the present invention.
FIG. 4 shows ultrasonic signals of internal defects of a Potential Transformer (PT) collected at different measuring points according to an embodiment of the present invention.
Fig. 5 is a suspected abnormal lead through pipe L-shaped turning ultrasonic sensor arrangement according to an embodiment of the invention.
FIG. 6 is a wavelet time-frequency map of the ultrasonic measuring point 1 and the measuring point 2 according to the embodiment of the invention.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.
Referring to fig. 1-6, in order to better improve the diagnosis accuracy, the selection of the detected GIS follows the following principle: (1) the power station unit where the GIS to be tested is located is debugged; (2) and the equipment normally generates power and operates.
The partial discharge diagnosis method of the gas insulated switchgear is characterized by comprising the following steps: the method comprises the following specific steps:
s1 checks that the ultrasonic partial discharge detection and location system needs to verify proper operation and that the sensors are operating properly.
S2: collecting partial discharge signals of the GIS equipment by using an ultrasonic partial discharge detection and positioning system; and comparing and analyzing the acquired detection signals with background noise signals and typical ultrasonic partial discharge signals, selecting abnormal detection signals, screening, processing and analyzing data, and preliminarily determining whether partial discharge exists and the type of partial discharge.
After data acquisition is finished, data analysis is firstly carried out, and whether partial discharge exists in the GIS or not and the type of the partial discharge are preliminarily analyzed according to the signal characteristics and the detection part.
S3: and carrying out frequency spectrum analysis on the original ultrasonic signals, eliminating signals such as mechanical vibration or external corona and the like, and diagnosing by using a positioning method if the frequency spectrum analysis result is similar to the frequency spectrum distribution of the typical ultrasonic partial discharge signal.
The detection data spectrum analysis needs to eliminate external interference such as vibration, corona and the like, eliminate GIS internal discharge, and further adopt a comprehensive positioning method to carry out diagnosis if the internal discharge cannot be eliminated.
S4: and finally, a sound-electricity combined positioning method, an ultrasonic time delay positioning method and an ultrasonic wavelet time-frequency positioning method are selected for comprehensive positioning, various external interferences are further eliminated, and the discharge defect is accurately positioned, so that correct diagnosis of GIS partial discharge is realized, and related suggestions are provided for GIS equipment operation and maintenance according to the diagnosis result.
The first embodiment is as follows:
after detecting an abnormal signal, a B-phase air chamber of a 220kV GIS bus voltage transformer searches for the position of a discharge point by using an acoustoelectric joint positioning method, as shown in FIG. 2, the positions of an ultrahigh frequency measuring point and an ultrasonic measuring point are shown, and in order to eliminate space corona interference, an ultrahigh frequency background sensor is arranged near a detected air chamber to detect space corona. As shown in fig. 3, the ultrahigh frequency signals (channel 1 and channel 2) and the ultrasonic signals (channel 3) collected by the oscilloscope are shown, the ultrahigh frequency sensor and the ultrasonic sensor arranged both measure the ultrahigh frequency signals and the ultrasonic signals excited by the local discharge, while the background ultrahigh frequency sensor does not measure the space corona signals, and accordingly, it is determined that the abnormal signals originate from the inside of the device. The time axis of the oscilloscope is expanded to a level of mu s, and the time delay of the ultrasonic signal and the ultrahigh frequency signal can be read to be about 75 mu s. The time delay and the ultrasonic wave are in SF6The equivalent propagation velocity in the gas is multiplied by 140m/s, and the distance from the local discharge source to the ultrasonic measuring point 1 is calculated to be about 1cm, which indicates that the local discharge defect is at the position of the ultrasonic sensor 1 and is close to the outer wall of the device.
However, corona discharge of other devices of the transformer substation may also be measured by the ultrasonic sensor and the ultrahigh frequency sensor which are positioned in an acoustic-electric combined manner, and usually, the distance between the external corona discharge point and the sensor is relatively long. Therefore, when the acoustoelectric joint positioning method is used, special attention should be paid to whether the ultrahigh frequency background sensor for detecting space corona detects an abnormal discharge signal, once the background sensor is also triggered, comprehensive analysis should be performed on the basis of the acoustoelectric joint positioning in combination with other positioning methods, so as to ensure that a correct diagnosis result is obtained.
The ultrasonic time delay positioning method comprises the steps of arranging a plurality of ultrasonic sensors connected with oscilloscope detection channels at different positions of a GIS shell to receive signals when signals are acquired, triggering and acquiring signals of each channel by using an oscilloscope, reading time delay of the signals of each channel, and calculating to obtain a three-dimensional coordinate position of a partial discharge defect according to a formula (1), namely the three-dimensional coordinate position of the partial discharge defect
In the formula: c represents the signal propagation speed, and the medium speed of the ultrasonic signal in the GIS is about 140 m/s; Δ tij represents the time delay for the signal to reach sensor i and sensor j; (x)s，ys，zs) Three-dimensional position coordinates representing partial discharge defects, (x)i，yi，zi) And (x)j，yj，zj) Three-dimensional position coordinates of the sensor i and the sensor j are shown, and i, j are 1, 2, 3, and 4, respectively.
Because the GIS has a unique pipeline structure, the GIS can be regarded as a linear structure when a time delay positioning method is used, and positioning calculation is carried out in a one-dimensional or two-dimensional space by using a simplified method. Under an ideal condition, only 2 sensors arranged at different positions on the outer surface of the GIS shell are required to simultaneously receive ultrasonic signals, and after time delay of two-channel signals is read, the partial discharge defect position can be obtained by calculating according to the formula x being 0.5 (L-c delta t) delta t. The signal source position is judged by continuously adjusting the relative position of the sensor to change the signal arrival time delay, so that the complex calculation is avoided. In the field detection, one sensor is used as a central sensor and fixed at a certain detection position of the GIS, other sensors with adjustable positions are arranged around the central sensor, and if the signal of the central sensor always leads the other sensors, the position of the partial discharge defect close to the central sensor can be judged. And (3) detecting each GIS measuring point in sequence by adopting a sequential positioning method, so that whether the abnormal signal comes from the inside of the GIS or not can be determined, and the specific position of the partial discharge defect can be found.
FIG. 4 shows the ultrasonic signals of 3 detection channels triggered by PT internal defects collected by an oscilloscope. And (3) observing the waveforms of the measuring points, discharging at the same time, leading the signal of the ultrasonic measuring point 1 to the ultrasonic measuring point 2, leading the signal of the ultrasonic measuring point 2 to the ultrasonic measuring point 3, and under the condition that the propagation path is a straight line, the signal amplitude of the ultrasonic measuring point 1 is the largest, and the signal amplitude of the ultrasonic measuring point 3 is the smallest. According to the analysis, the PT internal defect is closest to the ultrasonic measuring point 1 and farthest to the ultrasonic measuring point 3, which is consistent with the sound and electricity combined positioning result.
During the propagation process of the ultrasonic signal, the attenuation of the high-frequency component of the ultrasonic signal is obvious along with the increase of the propagation distance. Therefore, on the basis of multi-channel signal time delay positioning, the attenuation condition of high-frequency components of signals of all channels can be directly observed by using a wavelet time-frequency analysis method, so that the distance between a signal source and sensors at different positions is further confirmed, and GIS partial discharge reliable positioning is realized. An ultrasonic sensor detects abnormal signals at the A-phase L-shaped turning position of a 220kV GIS lead through pipe, and signal source positioning is carried out through a wavelet time-frequency positioning method. FIG. 5 shows the arrangement of multiple points of the sensor, wherein the measuring points 1 and 2 are arranged from bottom to top, and FIGS. 1-5 show wavelet time-frequency maps of signals of the measuring points 1 and 2. As is clear from the figure, the ultrasonic signal is received by the measuring point 1 earlier than the measuring point 2, and the energy of the high-frequency part of the ultrasonic signal collected by the measuring point 1, which is 80kHz or more, is greater than that of the signal collected by the measuring point 2. According to the signal time delay and frequency spectrum comprehensive analysis of the measuring points 1 and 2, the abnormal signal source is closer to the measuring point 1.
The local discharge ultrasonic signals of various types of GIS acquired on site by adopting the method are analyzed, and the fact that the local discharge signals and interference signals such as mechanical vibration, space corona and the like have obvious difference on time domain characteristics and frequency domain distribution is found, so that the method is favorable for defect type identification. And an acoustoelectric combined positioning method, an ultrasonic time delay positioning method and an ultrasonic wavelet time-frequency positioning method are also applied to GIS partial discharge on-site detection, so that external interference signals are eliminated, the GIS internal partial discharge defect is accurately positioned, and accurate diagnosis is realized.
In the embodiment, a Gas Insulated Switchgear (GIS) partial discharge diagnosis method is utilized, GIS partial discharge can be diagnosed quickly, conveniently and accurately, the problems that the traditional ultrahigh frequency detection method is influenced by factors such as position, structure and material are solved, and the defect that whether insulation defects exist in the GIS or not are difficult to diagnose accurately due to numerous interference factors is avoided. The partial discharge pulse of the tested GIS is collected, data is screened, processed and analyzed, then the original ultrasonic signal is subjected to spectrum analysis, and after a fault signal is determined, a comprehensive positioning method is further used for positioning and diagnosing, so that correct diagnosis of partial discharge of the GIS can be more accurately performed. The embodiment can also conveniently provide suggestions for the healthy operation and maintenance of the GIS according to the result obtained by analyzing and calculating in the test process.
Compared with the traditional test method, the embodiment greatly improves the rapidity, the convenience and the accuracy, greatly reduces the dependence on the test environment, finds and processes faults in advance, reduces the equipment fault rate of a power plant, and greatly reduces the overhaul and maintenance cost.
In the embodiment, a portable ultrasonic partial discharge detection and positioning system is adopted for detection; the sensor is used for testing partial discharge.
The data screening, processing and analyzing of the embodiment comprises the steps of comparing and analyzing a detection signal with a background noise signal and a typical ultrasonic partial discharge signal, selecting the detection signal with abnormality, and preliminarily judging whether partial discharge exists in the GIS or not and judging the type of the partial discharge according to signal characteristics and detection positions.
The data screening of the embodiment is to perform spectrum analysis on the original ultrasonic signals and to remove signals such as mechanical vibration or external corona.
The positioning method of the embodiment is to diagnose by using a comprehensive positioning method combining an acoustoelectric combined positioning method, an ultrasonic time delay positioning method and an ultrasonic wavelet time-frequency positioning method under the condition that the frequency spectrum analysis result is similar to the frequency spectrum distribution of a typical ultrasonic partial discharge signal.
In the spectrum analysis of the embodiment, the fault type is determined by comparing the characteristics of insulation air gap discharge, point discharge and the like.
The ultrasonic signal judgment of the interference in the embodiment judges different signal types according to the frequency domain distribution map, the frequency distribution of the ultrasonic signal excited by partial discharge in the GIS is wide, and the upper limit of the frequency of the energy concentration part exceeds 100 kHz; the frequency distribution of the mechanical vibration signal is relatively narrow, and the upper frequency limit of the energy concentration portion is usually lower than 50 kHz.
The comprehensive positioning method diagnosis of the embodiment adopts the sound-electricity combined positioning method to carry out defect positioning, which is helpful to eliminate the common interference of mechanical vibration. When the sound-electricity combined positioning result is in doubt and the GIS basin-type insulator is completely shielded and cannot carry out ultrahigh frequency partial discharge detection, the method for positioning the partial discharge of the GIS with higher reliability by adopting the sound wave time delay positioning method is adopted, and the three-dimensional coordinate position of the partial discharge defect can be obtained by adopting a calculation formula; on the basis of multi-channel signal time delay positioning, a wavelet time-frequency analysis method is utilized to directly observe the attenuation of high-frequency components of signals of all channels, so that the distance between a signal source and sensors at different positions is further confirmed, and the GIS partial discharge reliable positioning is realized.
The ultrasonic partial discharge detection and positioning system for detecting the channels in the embodiment comprises 1 4-channel oscilloscope with a high sampling rate, an ultrasonic sensor corresponding to each channel and a preposed signal amplifier, wherein the sampling rate of the oscilloscope is 5GS/s, and the analog bandwidth is 1 GHz. The frequency response effective detection frequency band is 10-200kHz, the resonance frequency is 30kHz, and the maximum detection sensitivity exceeds 80 dB. The preamplifier matched with the sensor has very good environmental noise suppression capability and linear amplification level in a differential amplification mode, and the amplification factor is adjustable in three stages of 20-60 dB.
In the embodiment, the application of the sound-electricity combined positioning method, the ultrasonic time delay positioning method and the ultrasonic wavelet time-frequency positioning method in GIS partial discharge field detection is adopted, the GIS internal partial discharge defect is accurately positioned, and correct diagnosis of GIS partial discharge is realized.
And will be apparent to those skilled in the art from the foregoing description.
In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an illustration of the structure of the present invention. Equivalent or simple changes in the structure, characteristics and principles of the invention are included in the protection scope of the patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.
Claims (10)
1. A partial discharge diagnosis method for a gas insulated switchgear is characterized by comprising the following steps: the method comprises the following specific steps:
s1: determining GIS equipment of a tested hydropower station, and checking whether ultrasonic partial discharge detection and positioning system equipment and a sensing device normally operate or not;
s2: collecting partial discharge signals of the GIS equipment by using an ultrasonic partial discharge detection and positioning system; comparing and analyzing the acquired detection signals with background noise signals and typical ultrasonic partial discharge signals, selecting abnormal detection signals, screening, processing and analyzing data, and preliminarily determining whether partial discharge and partial discharge types exist;
s3: carrying out frequency spectrum analysis on the original ultrasonic signals, eliminating signals such as mechanical vibration or external corona and the like, and if the frequency spectrum analysis result is similar to the frequency spectrum distribution of typical ultrasonic partial discharge signals, diagnosing by using a positioning method;
s4: and finally, comprehensive positioning is selected, various external interferences are further eliminated, and the discharge defect is accurately positioned, so that correct diagnosis of GIS partial discharge is realized, and related suggestions are provided for operation and maintenance of GIS equipment according to the diagnosis result.
2. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: in step S1: the ultrasonic partial discharge detection and positioning system is a system for detecting GIS partial discharge, and the detection of whether equipment and sensing devices of the ultrasonic partial discharge detection and positioning system operate normally comprises the steps of checking whether each sensor of the ultrasonic partial discharge detection and positioning system fails or not and judging whether the detection precision reaches the standard or not; the sensor performs partial discharge diagnosis.
3. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: in step S2: the data screening, processing and analyzing are data elimination, comparison, processing and analysis.
4. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: in step S2: the data processing and analysis comprises elimination of interference caused by noise, comparison of detected data with typical ultrasonic partial discharge signals, and further positioning diagnosis when frequency spectrums are similar.
5. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: in step S2: the data processing and analysis is to perfect a GIS ultrasonic partial discharge signal analysis method by comparing ultrasonic signal characteristics of point discharge, suspension potential discharge, insulation internal discharge and insulation surface discharge and combining means such as frequency spectrum analysis.
6. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: oscillation pulses of insulation air gap discharge and creeping discharge in the GIS can appear in positive and negative half cycles of a power frequency period, and the oscillation pulses have the advantages of uniform period, large amplitude, long oscillation time of a single pulse, obvious 100Hz frequency correlation and obvious phase aggregation signal identification; in addition, the point discharge of which the oscillation pulse usually only appears in a certain power frequency half cycle and the polarity is very obvious is identified.
7. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: in step S3: the positioning method is based on abnormal signal positioning of an ultrasonic principle and analyzes time domain characteristics and spectrum characteristics of detection signals.
8. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: the diagnostic method and the ultrasonic partial discharge detection and positioning system used for detecting the channels comprise a four-channel high-sampling-rate oscilloscope, an ultrasonic sensor corresponding to each channel and a preposed signal amplifier.
9. The method for diagnosing partial discharge of a gas insulated switchgear according to claim 8, wherein: the sampling rate of the oscilloscope is 5GS/s, and the analog bandwidth is 1 GHz; the frequency response effective detection frequency band is 10-200kHz, the resonance frequency is 30kHz, and the maximum detection sensitivity exceeds 80 dB; the preamplifier matched with the sensor has very good environmental noise suppression capability and linear amplification level in a differential amplification mode, and the amplification factor is adjustable in three stages of 20-60 dB.
10. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, characterized in that: in step S4: the comprehensive positioning comprises an acoustic-electric combined positioning method, an ultrasonic time delay positioning method and an ultrasonic wavelet time-frequency positioning method.
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Cited By (5)
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| CN116223998A (en) * | 2023-05-08 | 2023-06-06 | 四川省菁蓉和欣科技有限公司 | Acoustic-electric combined positioning method for partial discharge inside large transformer |
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| CN113447777A (en) * | 2021-06-29 | 2021-09-28 | 国网湖北省电力有限公司宜昌供电公司 | Ultrasonic arrival time automatic acquisition method based on multiple criteria |
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| CN116223998A (en) * | 2023-05-08 | 2023-06-06 | 四川省菁蓉和欣科技有限公司 | Acoustic-electric combined positioning method for partial discharge inside large transformer |
| CN116223998B (en) * | 2023-05-08 | 2023-08-22 | 四川省菁蓉和欣科技有限公司 | Acoustic-electric combined positioning method for partial discharge inside large transformer |
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