Background technology
Gas insulated combined electrical equipment (Gas Insulated Switchgear, below summary is for GIS) is because characteristics such as its insulativity height, compact conformation, floor area are little, unfailing performance height, in the generating plant of electric system and transformer station, is used widely.But in use can run into some problems, be main with Insulation Problems wherein.
GIS introduces defective easily in manufacturing and installation process;, metal tip too high like dust, electrically conductive particles, stress, interior dress are loosening etc., the increase of the As GIS operation time limit, and defective can develop seriously gradually; Under extraneous inducements such as superpotential or operating process, will cause puncture or flashover phenomenon.These insulation faults take place before, normal phenomenon with shelf depreciation.The appearance of shelf depreciation often explains that there is the defective of installation, manufacturing even design aspect in GIS.
Above-mentioned partial discharge phenomenon can excite the electromagnetic wave that reaches thousands of megahertzes (GHz); The inner shelf depreciation sustainable development of GIS causes Fault of Insulating Breakdown easily; Thereby power outage appears, and cause damage to national economy, just seem particularly important so the shelf depreciation of GIS monitored and locate.
The detection method for local discharge of existing GIS; Like the Chinese patent notification number is 100363747 " gas insulation combined electric device local discharge superhigh frequency detection apparatus and method ", discloses a kind ofly to utilize the method that ultrahigh frequency detects local discharge detects to GIS, though avoided the interference of corona discharge in the air; Detection efficiency is high; But the requirement to antenna performance and data sampling rate is very high, and degree of accuracy is not very high, in addition; This method only relies on the detection method of ultrahigh frequency that shelf depreciation is monitored, and comparatively accurate localization is not carried out in the position of shelf depreciation.
And for example the Chinese patent notification number is 100363748 " online detection and location device of local discharge of gas-insulator switchgear and localization method "; Though disclose localization method to the GIS shelf depreciation; But its method that still only relies on ultrahigh frequency to detect positions, and locatees accurate inadequately.And no matter above-mentioned patent and related art all exist the location accurate inadequately in varying degrees, obtain the accurate inadequately too drawback of characteristic of discharge signal, thus influence maintenance and the science analyzed.
In addition, acoustic emission also capable of using (Acoustic Emission, below summary is AE) is also referred to as the stress wave emission sometimes, and it often is applied in the detection to aspects such as the structural deformation of material and crack propagation.But,, can make that again detection efficiency is low, and influenced by the GIS proper vibration if utilize acoustic emission that the GIS shelf depreciation is detected.
In view of this, how a kind of method for detecting partial discharge of gas insulated switchgear is provided, reduces above-mentioned drawback and become the technical matters that industry needs to be resolved hurrily.
Summary of the invention
The technical matters that the present invention solved is to provide a kind of method for detecting partial discharge of gas insulated switchgear, to improve detection efficiency, obtains characteristic accurately, improves locating speed and accuracy.
For solving the problems of the technologies described above; The invention provides a kind of gas insulated combined electrical equipment (GIS) detection method for local discharge; It may further comprise the steps: at first in said gas insulated combined electrical equipment relevant position uhf sensor is set; The ultra-high frequency signal that said uhf sensor is monitored carries out spectrum analysis, after the overfrequency examination, confirms to detect frequency band; Then the ultra-high frequency signal in the said detection frequency band being carried out single-frequency follows the tracks of; When appearance is unusual in the single-frequency tracing process, measures the relevant ultrahigh frequency characteristic that unusual ultra-high frequency signal occurs, and carry out Primary Location, confirm a region of discharge according to the ultrahigh frequency characteristic; In said region of discharge, calibrate AE sensor is set then, and acoustic emission signal is monitored; Measure the relevant characteristics of Acoustic Emission data that monitor acoustic emission signal at last, the location of accomplishing point of discharge according to the characteristics of Acoustic Emission data.
Said GIS detection method for local discharge also is included in and carries out before single-frequency is followed the tracks of the gas componant in the said GIS being detected and analyzing, and disturbs to help getting rid of, and confirms to detect frequency band.
Said GIS detection method for local discharge also comprises: if in the single-frequency tracing process, do not occur unusual; Acoustic emission detection point then is set and carries out acoustic emission detection; Transfer acoustic emission signal to sub-audible sound; If sub-audible sound occurs unusual, then measure the relevant characteristics of Acoustic Emission data that monitor acoustic emission signal, accomplish location according to the characteristics of Acoustic Emission data to point of discharge.
Said GIS detection method for local discharge also comprises: behind the location of accomplishing point of discharge, comprehensively compare and analyze in conjunction with relevant ultrahigh frequency characteristic and characteristics of Acoustic Emission data, and set up the coherent detection database.
Carry out acoustic emission signal when monitoring coming examination signal point of maximum intensity through the position of moving calibrate AE sensor, and the signal point of maximum intensity being measured above-mentioned.And when the relevant ultrahigh frequency characteristic of unusual ultra-high frequency signal measure occurring, also comprise the situation of measuring applied voltage.
Wherein, it is the ultra-high frequency signal of selecting single-frequency that said single-frequency is followed the tracks of, and the amplitude of its signal is carried out Continuous Tracking; Said uhf sensor is to be located at the discontinuous place of said gas insulated combined electrical equipment outer cover metal body.
In addition, carrying out Primary Location is the mistiming according to time domain waveform in the ultrahigh frequency characteristic; And be the sound intensity according to each calibrate AE sensor position in the characteristics of Acoustic Emission data to the location of point of discharge.
Method for detecting partial discharge of gas insulated switchgear of the present invention; Be the method for comprehensive detection that detects the kneading acoustic emission detection through ultrahigh frequency, shelf depreciation in the GIS monitored and located, wherein; Carrying out the ultrahigh frequency detection method earlier monitors local discharge signal; And when monitoring discharge signal, it is carried out the measurement of ultrahigh frequency characteristic, and then Primary Location, confirm a region of discharge; Subsequently, utilize the acoustic emission detection method in above-mentioned region of discharge, to detect, thereby obtain characteristics of Acoustic Emission data and final confirming point of discharge.Said method is not only more effective to the GIS partial discharge monitoring, and the ultrahigh frequency characteristic that obtains and characteristics of Acoustic Emission data compare of analysis each other, so have more science, helps the scientific research to the GIS shelf depreciation; And after the Primary Location through the ultrahigh frequency characteristic; In the less region of discharge of scope, carry out the acoustic emission detection location; Not only efficiently solve the inefficient problem of acoustic emission detection, and make the location more accurately effectively, can also find the exact position of point of discharge sooner.
Embodiment
Below through preferable instantiation embodiment of the present invention is described, those skilled in the art can understand other advantages of the present invention and effect easily by the content that this instructions disclosed.The present invention also can implement or uses through other different instantiations, and each item details in this instructions also can be based on different viewpoints and application, carries out various modifications and change under the spirit of the present invention not deviating from.
Gas insulated combined electrical equipment described in the present invention (Gas Insulated Switchgear, below summary is GIS) detection method for local discharge can be applicable to the generating plant of electric system and the inner partial discharge monitoring of GIS, location and the research of transformer station.
Referring to Fig. 1, the method for detecting partial discharge of gas insulated switchgear flow process of a preferred embodiment of the present invention may further comprise the steps:
At first, execution in step S11 is provided with uhf sensor in said gas insulated combined electrical equipment relevant position; The ultra-high frequency signal that said uhf sensor is monitored carries out spectrum analysis; After the overfrequency examination, confirm to detect frequency band, need to prove, in principle; Said uhf sensor can be located at the discontinuous place of said GIS outer cover metal body; In present embodiment, for example be arranged at positions such as no metal flange disc insulator among the GIS, insulator plug hole, grounding switch place insulator, and the uhf sensor of selecting for use is an external, the detection frequency is 300MHz to 1.1GHz; And the shell of uhf sensor wherein five faces all has metallic shield, and only one side does not shield with directional couple uhf electromagnetic wave signal.
In addition, in present embodiment, carrying out spectrum analysis is to be realized by the corresponding frequency spectrum analyser; Start the full frequency band scanning of spectrum analyzer; Can measure all background scene frequencies that monitor by uhf sensor, help to get rid of the erroneous judgement that produces because of background interference, get rid of electromagnetic interference (EMI).And for detect frequency band confirm note also: for the ultrahigh frequency in-vivo measurement, frequency band is selected to depend primarily on the GIS cylinder internal diameter, is example with 110kV GIS, and general pipe diameter is 30cm, and detecting lower-frequency limit needs greater than 300MHz.For the ultrahigh frequency in-vitro measurements; Owing to can only on maskless insulator basin, measure; The thickness of insulator basin has determined the frequency band selection, also need consider the frequency band of external interference simultaneously, considers with sensitivity two aspects from anti-interference; When adopting in-vitro measurements, common extraneous background interference is in 250~750MHz scope.Therefore the frequency band range of uhf sensor should be chosen between 700~1300MHz when in vitro method is measured.Consider frequency selectivity and anti-interference factor, high-end frequency also should be higher, so survey frequency can be selected between 700~1500MHz.
In step S12, the gas componant in the said GIS is detected and analyzes in addition, help equally to get rid of and disturb, confirm to detect frequency band.
Then; Carry out step S13; Be to follow the tracks of carrying out single-frequency according to the ultra-high frequency signal in step S11 and the definite detection of the step S12 frequency band, it is the ultra-high frequency signal of selecting single-frequency that said single-frequency is followed the tracks of, and the signal amplitude of this frequency is carried out Continuous Tracking; Thereby avoid interference band fully, signal to noise ratio (S/N ratio) improves greatly.
Step S14 judges whether the ultra-high frequency signal of above-mentioned single-frequency tracking is unusual, judges promptly whether the ultra-high frequency signal amplitude of above-mentioned single-frequency occurs unusually.
If occur among the above-mentioned steps S14 then carrying out step S15 unusually, measure the relevant ultrahigh frequency characteristic that unusual ultra-high frequency signal occurs, and carry out Primary Location according to the ultrahigh frequency characteristic, confirm a region of discharge.Need to prove; Above-mentioned ultrahigh frequency characteristic for example comprises: Wave data, frequency spectrum data, phase data or the like; And can obtain by broadband high-speed oscillograph and spectrum analyzer, in addition, when measuring the relevant ultrahigh frequency characteristic that unusual ultra-high frequency signal occurs; Also comprise the situation of measuring applied voltage; Because the power of local discharge signal and characteristic and applied voltage have direct cause-effect relationship, the phase place of applied voltage is the important information of research discharge characteristic, therefore should guarantee as far as possible that voltage-phase is accurate.
In addition; The above-mentioned Primary Location of carrying out is to analyze according to the mistiming of time domain waveform in the said ultrahigh frequency characteristic to calculate and confirm; For example: two uhf sensors are set; And the high frequency response characteristic of these two uhf sensors, and the identical precondition of signal cable length under, the distance of establishing two uhf sensors is S, and discharge position is x to the distance of one of them uhf sensor; The mistiming that two sensors receives discharge signal is Δ t (can be learnt by waveform), and the velocity of propagation of uhf electromagnetic wave is c (3 * 10
8M/s), then discharge position can be calculated as follows: x=(c Δ t+s)/2; And according to mistiming of several pulses before the ultrahigh frequency original waveform, and consider inherent error, precision can reach 1m, wherein, requires oscillographic sampling rate can not be lower than 10
9Sa/s, bandwidth is not less than 1GHz.
Through the Primary Location of step S15, carry out step S17 then, in said region of discharge, calibrate AE sensor is set, and acoustic emission signal is monitored.Need to prove: in carrying out the acoustic emission detection process, (comprising monitoring and measurement) can be by calibrate AE sensor, external amplifier, main amplifier and parts such as wave detector, voice output, magnitude calculation and demonstration.Wherein, the resonance frequency of calibrate AE sensor is 30kHz, and survey frequency is 10kHz to 500kHz; And acoustic emission signal can be sent into the storage of broadband high-speed oscillograph, also can transfer sub-audible sound to, is convenient to the testing staff and judges whether sub-audible sound is unusual.
Then in step S18; Measurement monitors the relevant characteristics of Acoustic Emission data of acoustic emission signal; Accomplish the location of point of discharge according to the characteristics of Acoustic Emission data; And be the sound intensity to the location of point of discharge here according to each calibrate AE sensor position in the sofar characteristic; For example according to the intensity distributions of acoustic emission signal around the GIS shell, along the GIS enclosure axis to propagation condition, through the research of the attenuation of disc insulator, can know that the decay of acoustic emission signal is very fast, and can accomplish according to sound intensity contour map when carrying out static fixing; Acoustic emission signal when monitoring come examination signal point of maximum intensity through the position of moving calibrate AE sensor, and the signal point of maximum intensity is measured, and with intensity maximum point location, precision can reach 10cm above-mentioned carrying out.
If in step S14,, calibrate AE sensor is set and carries out acoustic emission detection if occur then carrying out step S16 unusually, transfer acoustic emission signal to sub-audible sound, judge whether sub-audible sound is unusual, if step S18 occurs then carrying out unusually.
At last, carry out step S19, behind the location of accomplishing, comprehensively compare and analyze in conjunction with relevant ultrahigh frequency characteristic and characteristics of Acoustic Emission data, and set up the coherent detection database point of discharge.For example: follow the tracks of collection of illustrative plates such as waveform, PHASE DISTRIBUTION figure, histogram with pulse train waveform, single pulse waveforms, unifrequency and show the GIS shelf depreciation; And these typical collection of illustrative plates and discharge characteristics, the analysis and the judgement that can be field actual measurement results provide reference and reference.In addition; In present embodiment; On the basis of the common discharge property defective of GIS that the above-mentioned detection database of research reacts; With the 110kV GIS six big types of discharging models that have been spaced apart fundamental construction, comprise that there is insulator, the nonmetal legacy of outer casing inner wall, high-pressure conductor metal tip, the suspended particle discharging model of flashover vestige on metallic particles, the metallic particles of outer casing inner wall, surface on the insulator.Through the weight and size, most advanced and sophisticated acutance, the kind of nonmetal legacy, the width of flashover vestige etc. that changes particle, can simulate different discharge severities.And, accumulated nearly thousand typical discharge data through a large amount of model tests of above-mentioned GIS shelf depreciation, the detection of dispatching from the factory, the on-the-spot detection.Wherein, the GIS equipment rated voltage that relates to can be from 110kV to 550kV, and that working condition comprises is in service, handing-over is withstand voltage, it is charged etc. to start.Therefore, the coherent detection database of above-mentioned foundation is owing to having more science, so help investigation and scientific research to the GIS shelf depreciation.
In sum; Method for detecting partial discharge of gas insulated switchgear of the present invention is not only more effective to the GIS partial discharge monitoring; And the ultrahigh frequency characteristic that obtains and characteristics of Acoustic Emission data compare of analysis each other; So have more science, help scientific research to the GIS shelf depreciation; And after the Primary Location through the ultrahigh frequency characteristic; In the less region of discharge of scope, carry out the acoustic emission detection location; Not only efficiently solve the inefficient problem of acoustic emission detection, and make the location more accurately effectively, and can find the exact position of point of discharge sooner.
The foregoing description is merely illustrative principle of the present invention and effect thereof, but not is used to limit the present invention.Any those skilled in the art all can be under spirit of the present invention and category, and the foregoing description is modified and changed.Therefore, rights protection scope of the present invention should be foundation with the scope of claims.