CN113376486A - Cable end discharge fault positioning method and device - Google Patents
Cable end discharge fault positioning method and device Download PDFInfo
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- CN113376486A CN113376486A CN202110680880.1A CN202110680880A CN113376486A CN 113376486 A CN113376486 A CN 113376486A CN 202110680880 A CN202110680880 A CN 202110680880A CN 113376486 A CN113376486 A CN 113376486A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/088—Aspects of digital computing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/11—Locating faults in cables, transmission lines, or networks using pulse reflection methods
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Abstract
The application provides a method and a device for positioning a discharge fault of a cable end, wherein the method comprises the following steps: acquiring a positioning waveform and a calibration waveform of the tested cable by a traveling wave measurement method, wherein the calibration waveform is obtained by calibrating the tested cable by a calibrator; if the partial discharge fault is an end discharge fault, comparing the positioning waveform with the calibration waveform according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform to obtain the waveform similarity of the positioning waveform and the calibration waveform; and determining the end discharge fault position of the tested cable according to the waveform similarity and the relation between the similarity value interval and the end discharge fault position. This application is based on cable transmission's decay characteristic, will be surveyed the location waveform and the calibration waveform of cable and compare, confirm the similarity of location waveform and calibration waveform according to the comparative result to judge whether cable end discharge fault location is the near-end or the source end, improved cable end discharge fault location's precision.
Description
Technical Field
The application relates to the technical field of cable partial discharge detection, in particular to a method and a device for positioning discharge fault of a cable end.
Background
Crosslinked polyethylene (XLPE) cables are becoming the mainstream product in power cables due to their good electrical and mechanical physical properties. The XLPE cable has potential insulation defects for a variety of reasons, and if the defects cannot be found and eliminated in time, the XLPE cable poses a serious threat to the safe and stable operation of the power system. The oscillation wave partial discharge test system can position local defects of the cable and find defect positions in the cable system in time so as to eliminate hidden dangers in time.
The existing oscillatory wave positioning technology is mature in positioning of a cable intermediate joint and a cable middle part, but partial discharge generated at a starting end and a tail end can only be positioned into end discharge, so that the technical problem of low partial discharge fault positioning precision exists.
Disclosure of Invention
The application provides a cable end discharge fault positioning method and device, which are used for solving the technical problem of low partial discharge fault positioning precision of the existing oscillatory wave positioning technology.
The application provides a cable end discharge fault positioning method in a first aspect, which includes:
acquiring a positioning waveform and a calibration waveform of a tested cable by a travelling wave measurement method, wherein the calibration waveform is obtained by calibrating the tested cable by a calibrator;
the partial discharge fault of the tested cable is preliminarily judged according to the positioning waveform and the calibration waveform, if the partial discharge fault is an end discharge fault, the positioning waveform and the calibration waveform are compared according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform to obtain the waveform similarity of the positioning waveform and the calibration waveform;
and determining the end discharge fault position of the tested cable according to the waveform similarity and by combining the relationship between the similarity value interval and the end discharge fault position.
Preferably, the process of preliminarily determining the partial discharge fault of the measured cable according to the positioning waveform and the calibration waveform specifically includes:
according to the positioning waveform and the calibration waveform, a first time difference and a second time difference are calculated through a time difference calculation mode of incident waves and reflected waves, if the first time difference is equal to the second time difference, the partial discharge fault of the tested cable is judged to be an end discharge fault, the first time difference is the time difference of the incident waves and the reflected waves obtained based on the positioning waveform, and the second time difference is the time difference of the incident waves and the reflected waves obtained based on the calibration waveform.
Preferably, the waveform characteristics specifically include: amplitude ratio, pulse width, and degree of dispersion.
Preferably, the determining, according to the waveform similarity and in combination with a relationship between a similarity value interval and an end discharge fault position, an end discharge fault position of the measured cable specifically includes:
if the waveform similarity is smaller than a first similarity threshold value, judging that the end discharge fault position is close to the end of the oscillatory wave source;
and if the waveform similarity is greater than a second similarity threshold, determining that the end discharge fault position is an end far away from the oscillatory wave source, wherein the second similarity threshold is greater than or equal to the first similarity threshold.
Preferably, before comparing the positioning waveform with the calibration waveform according to the waveform characteristics of the positioning waveform and the waveness characteristics of the calibration waveform, the method further includes:
and proportionally adjusting the positioning waveform and the calibration waveform until the incident wave peak values of the positioning waveform and the calibration waveform are equal.
This application second aspect provides a cable end discharge fault positioner, includes:
the device comprises a waveform acquisition unit, a waveform analysis unit and a control unit, wherein the waveform acquisition unit is used for acquiring a positioning waveform and a calibration waveform of a tested cable by a traveling wave measurement method, and the calibration waveform is obtained by calibrating the tested cable by a calibrator;
the waveform comparison unit is used for preliminarily judging the partial discharge fault of the tested cable according to the positioning waveform and the calibration waveform, and comparing the positioning waveform with the calibration waveform according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform if the partial discharge fault is an end discharge fault to obtain the waveform similarity of the positioning waveform and the calibration waveform;
and the discharge fault positioning unit is used for determining the end discharge fault position of the tested cable according to the waveform similarity by combining the relationship between the similarity value interval and the end discharge fault position, and the similarity comparison result is the comparison result of the waveform similarity and a preset similarity threshold.
Preferably, the process of preliminarily determining the partial discharge fault of the measured cable according to the positioning waveform and the calibration waveform specifically includes:
according to the positioning waveform and the calibration waveform, a first time difference and a second time difference are calculated through a time difference calculation mode of incident waves and reflected waves, if the first time difference is equal to the second time difference, the partial discharge fault of the tested cable is judged to be an end discharge fault, the first time difference is the time difference of the incident waves and the reflected waves obtained based on the positioning waveform, and the second time difference is the time difference of the incident waves and the reflected waves obtained based on the calibration waveform.
Preferably, the waveform characteristics specifically include: amplitude ratio, pulse width, and degree of dispersion.
Preferably, the determining, according to the waveform similarity and in combination with a relationship between a similarity value interval and an end discharge fault position, an end discharge fault position of the measured cable specifically includes:
if the waveform similarity is smaller than a first similarity threshold value, judging that the end discharge fault position is close to the end of the oscillatory wave source;
and if the waveform similarity is greater than a second similarity threshold, determining that the end discharge fault position is an end far away from the oscillatory wave source, wherein the second similarity threshold is greater than or equal to the first similarity threshold.
Preferably, the waveform comparing unit is further configured to:
and proportionally adjusting the positioning waveform and the calibration waveform until the incident wave peak values of the positioning waveform and the calibration waveform are equal.
According to the technical scheme, the method has the following advantages:
the application provides a method and a device for positioning a discharge fault of a cable end, wherein the method comprises the following steps: acquiring a positioning waveform and a calibration waveform of a tested cable by a travelling wave measurement method, wherein the calibration waveform is obtained by calibrating the tested cable by a calibrator; the partial discharge fault of the tested cable is preliminarily judged according to the positioning waveform and the calibration waveform, if the partial discharge fault is an end discharge fault, the positioning waveform and the calibration waveform are compared according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform to obtain the waveform similarity of the positioning waveform and the calibration waveform; and determining the end discharge fault position of the tested cable according to the waveform similarity and by combining the relationship between the similarity value interval and the end discharge fault position.
This application is based on cable transmission's decay characteristic, will be surveyed the location waveform and the calibration waveform of cable and compare, confirm the similarity of location waveform and calibration waveform according to the comparative result to judge whether cable end discharge fault location is the near-end or the source end, improved cable end discharge fault location's precision.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic flow chart of a cable end discharge fault location method provided in the present application;
fig. 2 is a schematic structural diagram of a cable end discharge fault location device provided in the present application;
Detailed Description
The existing oscillatory wave positioning technology is mature in positioning of a cable middle joint and a cable middle part, but can only position partial discharge generated at a starting end and a tail end into end discharge, and the reason is that the existing oscillatory wave partial discharge positioning method mainly adopts a traveling wave method for positioning at present, defect positioning is carried out according to the time difference of incident waves and reflected waves of a partial discharge point, and if the cable end discharges, according to the traveling wave principle, the time difference of the incident waves and the reflected waves is equal no matter the defect is at a near end or a far end, and further the near end discharge or the far end discharge cannot be clearly positioned through the traveling wave method, so that the technical problem of low positioning accuracy of the existing partial discharge fault is caused.
The application provides a cable end discharge fault positioning method and device, which are used for solving the technical problem of low partial discharge fault positioning precision of the existing oscillatory wave positioning technology.
In order to make the objects, features and advantages of the present invention more apparent and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the embodiments described below are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
By means of intensive studies on the near-end discharge phenomenon and the far-end discharge phenomenon, the applicant found that for the near-end discharge, t1＝0，t22L/V; for far-end discharge, t1＝L/V，t23L/V. Wherein, L: the total length of the cable; v: wave speed, t, at which a partially discharged signal propagates in a cable1At the peak time point of the incident wave, t2The peak time point of the reflected wave.
From the above parameter differences, it can be seen that, although the time difference between the incident wave and the reflected wave is Δ t ═ t in both the near end and the far end2-t12L/V, however, the applicant found, based on intensive studies on the transmission characteristics of the cable, that the near end t is close to10, and there is equivalence in calibration with a calibration source, that is, the incident wave is substantially free of attenuation and dispersion. For far end t1Because of the low pass of the cable, the amplitude of the incident wave has larger attenuation after passing through the cable, the rising edge of the incident wave can be obviously slowed down, and the remote end fault can be realized in the same wayThe reflected wave experiences 3L/V, which is more attenuated than the near-end fault reflected wave 2L/V.
By waveform comparison, applicants have found that since the far-end attenuation is greater than the near-end attenuation, the near-end fault and calibration waveform rising edges will be steeper than the far-end fault rising edges, and the reflected waves will exhibit the same characteristics, while the near-end fault and calibration waveform will be narrower than the far-end fault pulse width. The near-end fault and calibration waveforms are more similar.
Referring to fig. 1, based on the research findings of the above applicant, a first embodiment of the present application provides a method for locating a discharge fault at a cable end, including:
102, preliminarily judging the partial discharge fault of the tested cable according to the positioning waveform and the calibration waveform, and if the partial discharge fault is an end discharge fault, comparing the positioning waveform with the calibration waveform according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform to obtain the waveform similarity of the positioning waveform and the calibration waveform.
And 103, determining the end discharge fault position of the tested cable according to the waveform similarity and the relation between the similarity value interval and the end discharge fault position.
It should be noted that, according to the method provided in the embodiment of the present application, first, a positioning waveform and a calibration waveform of a measured cable are acquired by a traveling wave measurement method, where the acquisition manner of the calibration waveform may refer to: according to the conventional oscillatory wave equipment connection surveyed cable, carry out the calibration with the calibrator, obtain the calibration waveform, the acquisition mode of location waveform can refer to: the cable is pressurized with an oscillating wave according to the standard, thereby obtaining a voltage waveform and a positioning waveform.
Comparing the positioning waveform with the calibration waveform, comparing whether the time difference between the incident wave and the reflected wave of the positioning waveform meets the end discharge condition, if so, indicating that the position of the cable generating the partial discharge fault is the end position, comparing the positioning waveform with the calibration waveform according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform to obtain the waveform similarity of the positioning waveform and the calibration waveform, and if the similarity of the positioning waveform and the calibration waveform is higher, indicating that the fault occurs at the near-end; on the contrary, if the difference between the incident wave and the reflected wave and the calibration waveform is large, the pulse width is wider than the calibration waveform, and the dispersion is more serious, it indicates that the partial discharge point comes from the far-end tip.
The above is a detailed description of a first embodiment of a cable end discharge fault location method provided by the present application, and the following is a detailed description of a second embodiment of the cable end discharge fault location method provided by the present application.
On the basis of the first embodiment, a second embodiment of the present application provides a cable termination discharge fault location method, including:
further, the process of preliminarily determining the partial discharge fault of the cable to be measured according to the positioning waveform and the calibration waveform in step 102 specifically includes:
and calculating a first time difference and a second time difference through a time difference calculation mode of incident waves and reflected waves according to the positioning waveforms and the calibration waveforms, if the first time difference is equal to the second time difference, judging that the partial discharge fault of the tested cable is an end discharge fault, wherein the first time difference is the time difference of the incident waves and the reflected waves obtained based on the positioning waveforms, and the second time difference is the time difference of the incident waves and the reflected waves obtained based on the calibration waveforms.
Further, the waveform characteristics specifically include: amplitude ratio, pulse width, and degree of dispersion. If the amplitude ratio difference between the positioning waveform and the calibration waveform is smaller, the pulse width difference is smaller, the dispersion degree is lower, the waveform similarity is higher, and otherwise, the waveform similarity is lower.
Further, according to the waveform similarity, the relation between the similarity value interval and the end discharge fault position is combined, and the determining of the end discharge fault position of the tested cable specifically comprises the following steps:
if the waveform similarity is smaller than a first similarity threshold, judging that the end discharge fault position is close to the end of the oscillatory wave source;
and if the waveform similarity is greater than a second similarity threshold, determining that the end discharge fault position is the end far away from the oscillatory wave source, wherein the second similarity threshold is greater than or equal to the first similarity threshold.
Further, before comparing the positioning waveform with the calibration waveform, according to the waveform characteristics of the positioning waveform and the waveness characteristics of the calibration waveform, the method further includes:
and adjusting the positioning waveform and the calibration waveform in proportion until the incident wave peak values of the positioning waveform and the calibration waveform are equal.
The above is a detailed description of the second embodiment of the cable end discharge fault location method provided by the present application, and the following is a detailed description of the first embodiment of the cable end discharge fault location device provided by the present application.
Referring to fig. 2, a third embodiment of the present application provides a cable termination discharge fault locating device, including:
the waveform acquiring unit 201 is configured to acquire a positioning waveform and a calibration waveform of the cable to be measured by a traveling wave measurement method, where the calibration waveform is obtained by calibrating the cable to be measured by a calibrator;
the waveform comparing unit 202 is configured to preliminarily determine a partial discharge fault of the measured cable according to the positioning waveform and the calibration waveform, and if the partial discharge fault is an end discharge fault, compare the positioning waveform with the calibration waveform according to a waveform characteristic of the positioning waveform and a wave characteristic of the calibration waveform to obtain a waveform similarity of the positioning waveform and the calibration waveform;
and the discharge fault positioning unit 203 is used for determining the end discharge fault position of the tested cable according to the waveform similarity by combining the relationship between the similarity value interval and the end discharge fault position, wherein the similarity comparison result is the comparison result of the waveform similarity and a preset similarity threshold.
Further, in the waveform comparing unit 202, the process of primarily determining the partial discharge fault of the measured cable according to the positioning waveform and the calibration waveform specifically includes:
and calculating a first time difference and a second time difference through a time difference calculation mode of incident waves and reflected waves according to the positioning waveforms and the calibration waveforms, if the first time difference is equal to the second time difference, judging that the partial discharge fault of the tested cable is an end discharge fault, wherein the first time difference is the time difference of the incident waves and the reflected waves obtained based on the positioning waveforms, and the second time difference is the time difference of the incident waves and the reflected waves obtained based on the calibration waveforms.
Further, the waveform characteristics specifically include: amplitude ratio, pulse width, and degree of dispersion.
Further, according to the waveform similarity, the relation between the similarity value interval and the end discharge fault position is combined, and the determining of the end discharge fault position of the tested cable specifically comprises the following steps:
if the waveform similarity is smaller than a first similarity threshold, judging that the end discharge fault position is close to the end of the oscillatory wave source;
and if the waveform similarity is greater than a second similarity threshold, determining that the end discharge fault position is the end far away from the oscillatory wave source, wherein the second similarity threshold is greater than or equal to the first similarity threshold.
Further, the waveform comparing unit 202 is further configured to:
and adjusting the positioning waveform and the calibration waveform in proportion until the incident wave peak values of the positioning waveform and the calibration waveform are equal.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The terms "first," "second," "third," "fourth," and the like in the description of the application and the above-described figures, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A cable end discharge fault positioning method is characterized by comprising the following steps:
acquiring a positioning waveform and a calibration waveform of a tested cable by a travelling wave measurement method, wherein the calibration waveform is obtained by calibrating the tested cable by a calibrator;
the partial discharge fault of the tested cable is preliminarily judged according to the positioning waveform and the calibration waveform, if the partial discharge fault is an end discharge fault, the positioning waveform and the calibration waveform are compared according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform to obtain the waveform similarity of the positioning waveform and the calibration waveform;
and determining the end discharge fault position of the tested cable according to the waveform similarity by combining the relation between the similarity value interval and the end discharge fault position, wherein the similarity comparison result is the comparison result of the waveform similarity and a preset similarity threshold.
2. The method for positioning the discharge fault at the end of the cable according to claim 1, wherein the process of preliminarily determining the partial discharge fault of the cable to be tested according to the positioning waveform and the calibration waveform specifically comprises:
according to the positioning waveform and the calibration waveform, a first time difference and a second time difference are calculated through a time difference calculation mode of incident waves and reflected waves, if the first time difference is equal to the second time difference, the partial discharge fault of the tested cable is judged to be an end discharge fault, the first time difference is the time difference of the incident waves and the reflected waves obtained based on the positioning waveform, and the second time difference is the time difference of the incident waves and the reflected waves obtained based on the calibration waveform.
3. The method for locating the discharge fault at the end of the cable according to claim 1, wherein the waveform characteristics specifically include: amplitude ratio, pulse width, and degree of dispersion.
4. The method for positioning the discharge fault at the end of the cable according to claim 1, wherein the determining the discharge fault position at the end of the cable to be tested according to the waveform similarity and the relationship between the similarity value interval and the discharge fault position at the end specifically comprises:
if the waveform similarity is smaller than a first similarity threshold value, judging that the end discharge fault position is close to the end of the oscillatory wave source;
and if the waveform similarity is greater than a second similarity threshold, determining that the end discharge fault position is an end far away from the oscillatory wave source, wherein the second similarity threshold is greater than or equal to the first similarity threshold.
5. The method for locating the discharge fault of the cable end according to claim 1, wherein before comparing the locating waveform with the calibration waveform according to the waveform characteristics of the locating waveform and the waveform characteristics of the calibration waveform, the method further comprises:
and proportionally adjusting the positioning waveform and the calibration waveform until the incident wave peak values of the positioning waveform and the calibration waveform are equal.
6. A cable termination discharge fault locating device, comprising:
the device comprises a waveform acquisition unit, a waveform analysis unit and a control unit, wherein the waveform acquisition unit is used for acquiring a positioning waveform and a calibration waveform of a tested cable by a traveling wave measurement method, and the calibration waveform is obtained by calibrating the tested cable by a calibrator;
the waveform comparison unit is used for preliminarily judging the partial discharge fault of the tested cable according to the positioning waveform and the calibration waveform, and comparing the positioning waveform with the calibration waveform according to the waveform characteristics of the positioning waveform and the wave characteristics of the calibration waveform if the partial discharge fault is an end discharge fault to obtain the waveform similarity of the positioning waveform and the calibration waveform;
and the discharge fault positioning unit is used for determining the end discharge fault position of the tested cable according to the waveform similarity by combining the relationship between the similarity value interval and the end discharge fault position, and the similarity comparison result is the comparison result of the waveform similarity and a preset similarity threshold.
7. The cable end discharge fault location device according to claim 6, wherein the process of preliminarily determining the partial discharge fault of the tested cable according to the location waveform and the calibration waveform specifically comprises:
according to the positioning waveform and the calibration waveform, a first time difference and a second time difference are calculated through a time difference calculation mode of incident waves and reflected waves, if the first time difference is equal to the second time difference, the partial discharge fault of the tested cable is judged to be an end discharge fault, the first time difference is the time difference of the incident waves and the reflected waves obtained based on the positioning waveform, and the second time difference is the time difference of the incident waves and the reflected waves obtained based on the calibration waveform.
8. The cable end discharge fault locating device according to claim 6, wherein the waveform characteristics specifically include: amplitude ratio, pulse width, and degree of dispersion.
9. The cable end discharge fault location device according to claim 6, wherein determining the end discharge fault location of the tested cable according to the waveform similarity and the relationship between the similarity value interval and the end discharge fault location specifically comprises:
if the waveform similarity is smaller than a first similarity threshold value, judging that the end discharge fault position is close to the end of the oscillatory wave source;
and if the waveform similarity is greater than a second similarity threshold, determining that the end discharge fault position is an end far away from the oscillatory wave source, wherein the second similarity threshold is greater than or equal to the first similarity threshold.
10. The cable termination discharge fault locating device of claim 6, wherein the waveform comparing unit is further configured to:
and proportionally adjusting the positioning waveform and the calibration waveform until the incident wave peak values of the positioning waveform and the calibration waveform are equal.
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